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Surgery Howard B. Seim III, DVM, DACVS College of Veterinary Medicine Colorado State University, Fort Collins Colorado Feeding Tube Placement Key Points
Table 5: Route of administration determines tube diameter tube diameter: 3-5 French
Table 6: Drugs used as appetite stimulants Diazepam: cats - 2 mg/kg orally or 0.1 - 0.5 mg/cat IV Diazepam: dogs-14 mg/kg orally or 0.1 - 0.2 mg/kg IV Oxazepam: cats - 2.5 mg/cat Cyproheptadine: 2 mg/cat PO As a general rule, the closer one comes to the oral route of food intake and digestion, the more efficient is the assimilation and digestion of nutrients and the greater the flexibility in formula composition. Conversely, the further aboral one gets, the less efficient is the assimilation and digestion of nutrients and greater care must be taken when choosing formula composition. Route of administration also dictates feeding tube diameter (Table 5); tube diameter in turn dictates usable feeding formulas due to varying formula viscosity and particulate matter size. The most common routes of administration for enteral hyperalimentation include oral, nasoesophageal/ nasogastric, pharyngostomy, esophagostomy, gastrostomy, gastroduodenostomy, and jejunostomy. Each route has its indications, contraindications, advantages, disadvantages, and complications. Oral As a general rule, oral feeding is the method of choice if adequate amounts of nutrients can be consumed to meet the patient's protein and calorie needs. Several techniques have been used to successfully coax an animal to eat. Sending the patient home, if the disease state permits and if owners are capable of managing the patient, may prove successful. Petting and vocal reassurance is also helpful in stimulating patients to eat, however it is very time consuming. Highly palatable foods or food coverings (e.g., gravy) may stimulate the appetite. Warming foods (i.e., microwave oven) will increase aroma and palatability. Supplementing potassium (1 - 2 mEq/kg orally), giving vitamin B-complex in maintenance fluids (may directly stimulate appetite), and feeding diets high in zinc (zinc deficiency may decrease sense of smell and taste) have all been recommended and may have a place in appetite stimulation. Drugs may be used successfully to stimulate appetite. A list of drugs and their recommended dosages are given in Table 6. Appetite stimulant drugs are generally not adequate in replacing a patients caloric needs, however they may provide the stimulus necessary for resumption of eating. Appetite stimulants are contraindicated in patients suffering from severe malnutrition. Nasoesophageal/nasogastric Nasoesophageal/ nasogastric intubation is an easy, effective, and efficient means of providing enteral nutritional support. The availability of small bore, soft polyvinyl and silastic feeding tubes (i.e., 3 - 5 French 36 inch, Argyl or National Catheter Company) and low viscosity, nutritionally complete liquid diet formulations (see Table 3), and patient tolerance of tube placement has made nasoesophageal/ nasogastric tube placement a popular avenue for feeding malnourished patients. Nasoesophageal/ nasogastric tube placement is indicated in any patient with protein-calorie malnutrition that will not undergo oral, pharyngeal, esophageal, gastric, or biliary tract surgery. technique: Local nasal anesthesia, sedation, or light general anesthesia may be necessary for placement of a nasoesophageal/ nasogastric tube in dogs and cats. In the majority of cases, topical anesthetic or light sedation is all that is necessary for proper tube placement. anesthesia - cat Place 0.5-1 ml of 0.5% proparacaine hydrochloride (topical local anesthetic) into the nasal cavity. Tilt the head up to encourage the local anesthetic to coat the nasal mucosa. Repeat application of local anesthetic to ensure adequate anesthesia of the nasal mucous membrane. If the patient will not tolerate nasal intubation (i.e., if excess stress is required to place the nasoesophageal/ nasogastric tube; particularly with debilitated cats), administer 1 to 2 mg/kg of ketamine intravenously to obtain light general anesthesia. anesthesia - dog Place 1 to 2 ml of 2% lidocaine into the nasal cavity and tilt the head upwards for several seconds. Repeat application of local anesthetic before attempting to pass the nasoesophageal/ nasogastric tube. If the patient does not tolerate passage of the tube, sedation or light general anesthesia may be required. tube placement Select an appropriate size feeding tube (Table 7). Table 7: Tube size Cats - any weight 5 French X 91 cm Dogs - 2 to 15 kg 5 French X 91 cm Dogs - >15 kg 8 French X 91 cm Estimate the length of tube to be placed in the esophagus or stomach by placing the tube from the nasal planum along the side of the patient to the 7 or 8 th intercostal space (i.e., nasoesophageal) or last rib (i.e., nasogastric). It is the authors recommendation that the feeding tube not pass through the lower esophageal sphincter, as this may result in sphincter incompetence and esophageal reflux of hydrochloric acid, causing esophagitis. Place a tape marker on the tube once the appropriate measurement has been taken. Lubricate the tip of the tube with 5% lidocaine viscous prior to passage. Hold the patients head in a normal functional position (i.e., avoid hyperflexion or hyperextension). tube placement - cat Place the tube in the ventrolateral aspect of the external nares and pass it in a caudoventral medial direction into the nasal cavity. The tube will generally "drop" into the oropharynx and stimulate a swallowing reflex. Pass the tube to the predetermined distance. tube placement - dog Identify the prominent alar fold, and direct the tube from a ventrolateral location in the external nares, to a caudoventral and medial direction as it enters the nasal cavity. When the tube is introduced 2 to 3 cm inside the nostril, feel it contact the median septum at the floor of the nasal cavity. At this moment, push the external nares dorsally to facilitate opening the ventral meatus, elevate the proximal end of the tube, and continue to advance the tube into the oropharynx and esophagus. confirming esophageal placement Confirm esophageal placement by injecting 3 to 5 ml of sterile saline through the tube and eliciting a cough or placing 6 - 12 ml of air and auscultating for borborygmus at the xiphoid. Placement can also be confirmed by taking an x-ray of the chest. If the patient requires general anesthesia, visually confirm tube placement in the esophagus. securing the tube to the patient - cat Once the clinician is satisfied that the tube is properly placed, it should be sutured to the nose and head to ensure it will not be removed by the patient. In the cat, it is important that the tube not exit laterally and come in contact with the whiskers. Place the tube directly over the dorsal aspect of the nose and forehead and secure it with an encircling suture and Chinese finger trap. An Elizabethan collar is placed postoperatively to prevent iatrogenic tube removal. securing the tube to the patient - dog In the dog, the tube is secured to the lateral aspect of the nose and dorsal nasal midline with an encircling suture and Chinese finger trap, or cyanoacrylate glue. An Elizabethan collar should be used immediately postoperatively and until it is determined if the patient will tolerate the presence of the tube. tube management Place a column of water in the tube and cap it when not in use; this prevents intake of air, reflux of esophageal contents, and occlusion of the tube by diet. Three and 5 French feeding tubes come with appropriate size caps. Nasoesophageal/ nasogastric tubes can be left in place for several weeks, are well tolerated, easily removed, the patient can drink and swallow around the tube, and repeated orogastric intubation is prevented. Esophagostomy indications: Esophagostomy tube feeding is indicated in anorexic patients with disorders of the oral cavity or pharynx, or anorexic patients with a functional gastrointestinal tract distal to the esophagus. contraindications: Esophagostomy tube placement is contraindicated in patients with a primary or secondary esophageal disorder (e.g., esophageal stricture, after esophageal foreign body removal or esophageal surgery, esophagitis, megaesophagus). advantages: Advantages of esophagostomy tube feeding include ease of tube placement, tubes are well tolerated by the patient, large bore feeding tubes can be used allowing use of blenderized diets, tube care and feeding is easily performed by the client, patients can eat and drink around the tube, and tube removal can be performed anytime after placement. Esophageal tube placement eliminates coughing, laryngospasm, or aspiration occasionally associated with pharyngostomy tubes. disadvantage: The major disadvantage of esophagostomy tube is the need for general anesthesia during placement. placement: 
Provide general anesthesia. Place the patient in right lateral recumbency with the left side uppermost. The tube can be placed on either the right or left side of the midcervical region, however the esophagus lies slightly left of midline making left sided placement more desirable. Aseptically prepare the lateral midcervical area from the angle of the mandible to the thoracic inlet. Slightly extend the neck and hold the mouth open with a mouth speculum. Premeasure and mark a 20 to 24 French polyvinyl chloride feeding tube from the level of the mid-cervical region (i.e., exit point of feeding tube) to the level of the seventh or eighth intercostal space; ensuring mid- to caudal esophageal placement. Enlarge the two lateral openings of the feeding tube to encourage smoother flow of blended diets (Figure 1). This technique requires the use of an Eld feeding tube placement device. Place the oblique tip of the instrument shaft through the oral cavity and into the esophagus to the level of the mid cervical region (i.e., equal distance between the angle of the mandible and thoracic inlet) and palpate the tip as it bulges the cervical skin. Make a small skin incision over the device tip. Activate the spring loaded instrument blade until it penetrates esophageal wall, cervical musculature, subcutaneous tissue and is visible through the skin incision (Figure 2). Carefully enlarge the incision in the subcutaneous tissue, cervical musculature and esophageal wall with the tip of a #15 scalpel blade to allow penetration of the instrument shaft. Place a 2-0 Nylon suture through the side holes of the feeding tube and through the hole in the instrument blade (Figure 3). Tighten the suture until the tip of the instrument blade and feeding tube tip are in close apposition (Figure 4). Retract the instrument blade into the instrument shaft so the feeding tube tip just enters the instrument shaft (i.e., deactivating the instrument blade. Place sterile water-soluble lubricant on the tube and instrument shaft. Retract the instrument and pull the feeding tube into the oral 
cavity to its predetermined measurement (Figure 5). Remove the 2-0 Nylon suture to free the feeding tube from the instrument. Place a stylet through one of the side holes of the feeding tube and against its tip. Lubricate the feeding tube and advance it into the esophagus until the entire oral portion of the tube disappears (Figure 6). Gently retract the stylet from the oral cavity being careful to ensure its release from the feeding tube. Secure the tube to the cervical skin with a Chinese finger-trap suture of #1 
Novafil (Figure 7) . The exit point of the tube can be left exposed or bandaged. A column of water is placed in the tube and the exposed end capped with a 3 cc syringe; this prevents intake of air, reflux of esophageal contents, and occlusion of the tube by diet. Most patients tolerate the tube without the need of an Elizabethan collar (Figure 8). Esophagostomy tubes can be removed immediately after placement or left in place for several weeks to months. Care of the tube exit site may require periodic cleansing with an antiseptic solution. Tube removal is performed by cutting the finger trap suture and gently pulling the tube. No further exit wound care is necessary; the hole seals in one or two days and heals by 7 - 10 days. Complications: Complications associated with esophagostomy tube placement include early removal by the patient or vomiting the tube No significant long-term complications have been reported (e.g., esophagitis, esophageal stricture, esophageal diverticulum, or subcutaneous cervical cellulitis). Reflux esophagitis can occur from improper tube placement (i.e., through the lower esophageal sphincter) or esophageal irritation from the tube itself. Mid-esophageal placement of silicone rubber tubes greatly reduces the incidence of esophageal injury and eliminates reflux esophagitis. Pharyngostomy indications: Whenever it is necessary to provide nutritional supplementation to an anorexic patient (i.e., suffering protein-calorie malnutrition) or to patients that are unable or reluctant to ingest food orally (i.e., cleft palate, mandibular or maxillary fractures, oral neoplasia), a pharyngostomy tube should be considered. contraindications: Pharyngostomy tubes should not be used for nutritional management of patients with esophageal disorders (i.e., esophagitis, esophageal stricture, recent esophageal surgery, post esophageal foreign body removal, esophageal neoplasia). advantage: The major advantage of a pharyngostomy tube over a nasoesophageal/ nasogastric tube is tube diameter; pharyngostomy tubes are generally 20 to 24 French, thus accommodating a wider variety of diets. Pharyngostomy tubes are placed in the mid-esophagus; they should never be placed through the lower esophageal sphincter. Generally, if esophagostomy tube placement is possible, it is preferred over pharyngostomy as placement results in less complications. disadvantage: The disadvantage of pharyngostomy feeding is dysphagia or dyspnea due to improper placement. If the tube is place to close to the laryngeal apparatus irritation and mechanical obstruction can result in the above complications. placement: 
Provide general anesthesia. Position the patient in lateral recumbency, with the side receiving the pharyngostomy incision uppermost. Aseptically prepare a 4-cm-square area just caudal to the angle of the mandible. Hold the mouth open with a mouth speculum. Premeasure and mark a 20 to 24 French polyvinyl chloride feeding tube to the level of the seventh or eighth intercostal space; ensuring mid-esophageal placement. Place an index finger into the pharynx, near the base of the tongue (Figure 9). Palpate the epiglottis, thyroid gland, arytenoid cartilages, and hyoid apparatus. Flex the index finger toward the lateral aspect of the neck and identify the junction of the intrapharyngeal ostium and laryngopharynx; this is the proper location for pharyngostomy tube exit. Gently apply enough pressure to the lateral pharyngeal wall to create an externally visible bulge. A large, curved forceps can be substituted for the index finger to maintain the bulge. Make a 1 - 2 cm skin incision over the bulge and use a curved forceps to bluntly dissect subcutaneous tissue, pharyngeal muscle, and pharyngeal mucosa until the index finger or forceps becomes visible (Figure 10). With a curved forceps, grasp the tip of the pharyngostomy tube and pull the tip of the tube through the incision, into the oral cavity, and out of the mouth. Reinsert the tip of tube into the mouth and pass it into the mid-esophagus (i.e., pre-marked location on the feeding tube) A stylet is generally not necessary for placement in the esophagus. Secure the tube at its exit point with a Chinese finger trap technique (Figure 11) and to the patients neck to encourage the tube to remain at its dorsal aspect. Place a column of water in the tube and cap it with a 3 cc syringe when not in use; this prevents intake of air, reflux of esophageal contents, and occlusion of the tube by diet. When the tube is no longer required, cut the Chinese finger trap suture, pull the tube, and allow the pharyngeal wound heal by contraction and epithelialization. Complications: If the pharyngostomy tube is placed ventral and medial to the intrapharyngeal ostium and laryngopharynx, partial airway obstruction, coughing, and gagging may result. If the tube is improperly placed (i.e., through the lower esophageal sphincter), reflux esophagitis may occur. Vomiting the tube has also been reported. Gastrostomy indications: Tube gastrostomy is indicated in anorexic patients with a functional gastrointestinal tract distal to the esophagus or patients undergoing operations of the oral cavity, larynx, pharynx, or esophagus. contraindications: Gastrostomy tube placement is contraindicated in patients with primary gastric disease (e.g., gastritis, gastric ulceration, gastric neoplasia) or disorders causing vomiting. advantages: 
Advantages of gastrostomy tube feeding include ease of tube placement, patient tolerance, use of large bore feeding tubes, ease of tube care and feeding by the client, and oral feeding can commence while the tube is in place. disadvantages: Disadvantages include specialized equipment may be necessary (i.e., endoscope, special tube placement instruments), general anesthesia is required, feeding cannot be initiated the first 24 hours after tube placement, and depending upon placement technique tubes must remain in place for a minimum of 10 - 14 days before removal (i.e., to encourage adhesion formation between stomach and abdominal wall). Techniques for placement: Gastrostomy tubes can be placed percutaneously without the aid of an endoscope or feeding tube instrument, percutaneously with the aid of an endoscope or feeding tube instrument, or via laparotomy. Tubes placed percutaneously without the aid of an endoscope can be performed with or without gastropexy. Technique: percutaneous surgical placement with gastropexy 
General anesthesia and standard skin preparation of the left paralumbar fossa is performed. Instruct an unsterile assistant to pass a large bore stiff plastic stomach tube (e.g., as for decompressing patients with GDV) into the stomach. Palpate the left flank area until the bulging end of the stomach tube can be palpated and grasped. The tube should be grasped at a point 1 - 2 cm caudal to the last rib and 3 - 4 cm ventral to the transverse processes of lumbar vertebra 2, 3, and 4 (Figure 12). Hold the stomach tube in this position and make a 2 cm skin incision over the end of the tube. Bluntly dissect subcutaneous tissues and abdominal muscles to expose the wall of the stomach over the tube; take care not to enter the lumen of the stomach (Figure 13). Place a purse string suture full thickness in the stomach wall around the tube using 2-0 Maxon suture. Use a #11 scalpel blade to enter the stomach through the lumen of the stomach tube. Place a 20-24 French Foley catheter 3 - 4 cm into the lumen of the stomach tube. Place moderate traction on the purse string suture as the assistant slowly withdraws the stomach tube (Figure ) . Once the Foley catheter is out of the lumen of the stomach tube, inflate the bulb and place gentle traction on the catheter to bring it against the stomach wall. Tie the purse string suture snugly around the Foley catheter. Place three to four simple interrupted sutures of 2-0 Maxon from the stomach wall to the body wall to firmly pexy the stomach in place. Close subcutaneous tissues and skin around the exiting Foley catheter and secure the catheter to the skin with a Chinese finger trap suture of #1 Novafil (Figure ). advantages: Advantages of this technique include ease of tube placement, ease of finding the stomach in an anorectic patient, tube placement is quick, no special equipment (i.e.,. endoscope or feeding tube placement device) is needed to place the tube, surgical gastropexy ensures an immediate seal between the stomach wall and body wall, and confirmation of proper tube placement is performed during placement. Feeding tubes can be safely removed at any time after placement. This technique is the authors choice for placement of a gastrostomy feeding tube. Technique: percutaneous surgical placement without gastropexy Position and prepare the patient for aseptic surgery as described above. Prepare a 20 French Pezzar urinary catheter as follows: cut off and discard the dilated proximal end of the tube; cut off 1.5 cm of the remaining tube and set aside for use as an external flange; cut the remaining proximal end of the tube at a sharp angle. Cut a strand of #1 Braunamid suture to the length of the prepared feeding tube. Pass either a stiff, large bore stomach tube or feeding tube placement device from the oral cavity into the stomach. Palpate the tube bulging against the left body wall and direct it 1 - 2 cm caudal to the last rib and 2 - 3 cm ventral to the transverse processes of lumbar vertebrae 2 and 3. If a large bore stomach tube is being used, pass an 18 gauge hypodermic needle through the abdominal skin and into the lumen of the stomach tube. Place a strand of #1 Braunamid suture through the needle, into the stomach tube, and out through the mouth. Remove the stomach tube. If a feeding tube placement device is being used (see esophagostomy tube placement in this chapter), pass it into the stomach and direct it 1 - 2 cm caudal to the last rib and 2 - 3 cm ventral to the transverse processes of lumbar vertebrae 2 and 3. Activate the device and thread the #1 Braunamid suture through the hole in the instrument blade. Retract the blade into the instrument shaft and remove the instrument. In each technique (i.e., stiff stomach tube or feeding tube placement device), a strand of #1 Braunamid suture is entering the stomach through the left flank and exiting through the oral cavity. Thread the end of the suture exiting the oral cavity through the narrow end of an 18 gauge sovereign catheter and tie it to the proximal end of the prepared Pezzar urinary catheter (i.e., feeding tube). Pull the Pezzar catheter tightly into the flange of the sovereign catheter and apply lubricant to the sovereign catheter. Pull the #1 Braunamid suture exiting the left flank until the sovereign catheter tip exits the skin. Enlarge the skin incision 3 - 4 mm allowing easy delivery of the Pezzar catheter. Pull the catheter until the mushroom tip is snugly against the body wall; ensuring a seal between the stomach wall and body wall. Secure the catheter to the skin with a Chinese finger-trap suture using #1 Novafil. advantages: Advantages of this technique are no special instrumentation is required for placement and it is easy to perform. disadvantages: Disadvantages include the stomach is not pexied to the body wall (i.e., removal prior to 10 - 14 days could result in peritonitis) and confirmation of tube placement can only be performed endoscopically. Technique: percutaneous endoscopic placement without gastropexy Percutaneous endoscopic tube placement without gastropexy is performed as described for percutaneous surgical placement without gastropexy with the exception that the #1 Braunamid suture is placed from the left flank out through the oral cavity with the aid of an endoscope. Pass the endoscope into the stomach and insufflate its lumen with air. Make a 1mm skin incision in the left flank 1 - 2 cm caudal to the last rib and 2 - 3 cm ventral to the transverse processes of lumbar vertebrae 2 or 3. Pass an 18 gauge hypodermic needle through the skin incision and into the stomach lumen. Pass a strand of #1 Braunamid suture through the needle, into the stomach, retrieve it endoscopically, and bring it out through the mouth. Once the strand of suture is entering the left flank and exiting the oral cavity, place the feeding tube as described for percutaneous surgical placement without gastropexy. advantage: The advantage of endoscopic placement is direct visualization of tube placement throughout placement. disadvantage: The disadvantage is inability to perform surgical gastropexy to ensure an early and permanent seal between the stomach wall and body wall; tubes cannot be removed prior to 14 days after placement. Technique: laparotomy placement From a ventral midline laparotomy approach, bring the distal end a 20 French Foley or Pezzar catheter (i.e., bulb or mushroom tip) into the abdominal cavity through a stab incision in the left body wall. Exteriorize the ventral surface of the stomach, place a purse string suture in the body of the stomach, and make a stab incision in the center of the purse string suture with a #11 scalpel blade. Place the distal end of the feeding catheter in the lumen of the stomach and tighten the purse string suture around the catheter. Inflate the bulb (i.e., Foley) with saline and place gentle traction on the catheter to bring the body of the stomach in close apposition to the left body wall. Pexy the stomach wall to the abdominal wall with four 2-0 Maxon sutures. Secure the feeding tube to the skin with a Chinese finger-trap suture of #1 Novafil. Close the abdomen routinely. advantages: The advantage of gastrostomy tube placement via laparotomy is the ability to suture the stomach wall the the abdominal wall creating a early permanant gastropexy. disadvantages: The major disadvantage is performing a laparotomy to place the tube. This technique is generally performed when exploratory laparotomy is required for diagnosis or treatment of the patients primary disorder. Complications: The most severe complication of gastrostomy tube placement is early removal with leakage of gastric contents into the abdominal cavity and subsequent generalized peritonitis. This complication can be prevented by choosing a technique that results in an early permanent pexy of stomach to body wall (i.e., percutaneous surgical placement with gastropexy or via laparotomy). Other complications include vomiting and peristomal infection. Percutaneous gastroduodenostomy indications: Percutaneous gastroduodenostomy is indicated in patients with severe gastroesophageal reflux, swallowing disorders, aspiration pneumonia, or persistent vomiting of gastric origin. technique: Place a percutaneous gastrostomy feeding tube as described above. Use a Pezzar catheter feeding tube and remove the dome shaped tip of the mushroom end prior to placement. Tie a strand of 2-0 silk suture to the tip of an 8 - 10 French diameter, 60 to 110 cm, styleted duodenal feeding tube. Pass the duodenal tube through the gastrostomy tube and into the stomach. Visualize the duodenal tube endoscopically and grasp the silk suture with biopsy forceps. Gently retract the biopsy forceps into the endoscope port to pull the catheter tip against the endoscope. Reposition the dog in left lateral recumbancy, pass the endoscope through the pylorus and into the duodenum, advance the biopsy forceps to their full length, and release the catheter. Replace the biopsy forceps in the biopsy port and slowly remove the endoscope. Secure the duodenal feeding tube to the gastrostomy tube by seating the flanged end of the duodenal tube in the gastrostomy tube, and slowly remove the duodenal tube stylet. advantage: The advantage of this technique is placement of an enteral feeding tube without the need of laparotomy. disadvantage: Disadvantages include difficulty placing the tube in the duodenum, placement is difficult in patients less than 18 kg, migration of the tube from the duodenum, mechanical obstruction of the tube (i.e., kinking), specialized instrumentation necessary for placement, and radiographic assessment is necessary for tube placement confirmation. This technique is technically demanding and is recommended only for experienced endoscopists. Jejunostomy indications: Jejunostomy feeding is indicated in any patient undergoing oral, pharyngeal, esophageal, gastric, pancreatic, duodenal, or biliary tract surgery in which the intestinal tract distal to the surgical site is functional. Surgical patients with a neurologic status that may prevent postoperative feeding may also be considered. Immediate feeding of a highly digestible, low bulk diet in patients undergoing colonic surgery can be accomplished using a jejunostomy tube. Patients with preexisting protein-calorie malnutrition that must undergo major abdominal surgery are considered candidates for early enteral hyperalimentation via jejunostomy. Preferred technique placement: 
A celiotomy incision is required for placement of a jejunostomy feeding tube. A 5 French diameter, 91 cm (36 inch) infant feeding tube is recommended. Bring the distal tip of the feeding tube into the abdominal cavity through a 2-3 mm stab incision on the right or left body wall using a #11 scalpel blade. Select a segment of proximal jejunum, identify the normal direction of flow of ingesta (i.e. oral to aboral), and insure the selected segment can easily be mobilized to the feeding tube entrance location on the body wall. Make a 1-1.5 cm linear incision through the seromuscular layers of the antimesenteric border of the selected jejunal segment. Use a 10 gauge hypodermic needle or the point of a #11 scalpel blade and enter the lumen of the jejunum at the most aboral end of the incision. Place the distal end of the feeding tube through the incision and pass 25 - 30 cm (10 to 12 inches) of the tube aborally in the lumen of the jejunum. Lay the exiting portion of the tube in the 1 - 1.5 cm seromuscular incision and suture the tube in this "tunnel" by inverting the seromuscular layer over the tube with three or four interrupted Cushing sutures of 4-0 Maxon (Figure 7) . Pexy the tube exit site of the jejunum to the exit site at the body wall with four to five simple interrupted sutures of 4-0 Maxon (Figure 8). Omentum may be interposed between the jejunum and body wall. Insertion of an enterostomy feeding tube requires 10-15 minutes to perform. Secure the exiting feeding tube to abdominal skin using a Chinese finger-trap of 2-0 Novafil. The feeding tube exit point should be incorporated into a body bandage to prevent premature removal by the patient, technical staff, or client Patients with enterostomy feeding tubes can be feed immediately postoperatively. A column of water should be kept in the tube between feedings. Alternate technique: 
From a laparotomy approach, pass a 10-gauge needle through the abdominal wall from peritoneum to skin. Introduce the feeding tube into the abdominal cavity through the needle; remove the needle leaving the feeding tube with its hub outside the abdominal cavity (Figure 8). Now introduce the needle at an acute angle into the lumen of the jejunum and exit at an oblique angle; creating a seromuscular tunnel (Figure 10). Introduce the catheter into the beveled end of the needle then remove the needle leaving the catheter in the lumen of the jejunum. Thread the catheter into the lumen of the jejunum as previously described, suture the jejunum to the body wall, and secure the catheter to the skin with a Chinese finger trap friction suture (Figure 6). If the seromuscular tunnel is inadequate, create a 1.5 - 2 cm serosal tunnel using 1-2 Cushing sutures prior to pexy (Figure 11). Alternate technique: 
A 10 gauge needle is introduced into the antimesenteric border of the jejunal wall. The needle is inserted between the seromuscular and submucosal layers of the jejunal wall for a distance of 1.5 - 2 cm (Figure 12). Needle placement in cats and small dogs may be difficult due to their relatively thin bowel wall; for this reason, the author does not recommend this technique in cats and small dogs. Once a 3 - 4 cm tunnel is created, the needle is directed into the lumen and a 5 French, 36 inch silastic or polyurethane catheter is passed through the needle. The needle is removed leaving a 3 - 4 cm seromuscular tunnel (Figure 13). The catheter is exteriorized through a separate stab incision in the body wall and secured to the skin with a Chinese finger trap suture (Figure 6). The jejunum is attached to the body wall with three to four simple interrupted sutures of 3-0 or 4-0 Maxon (Figure 8). Complications Complications include premature removal, tube induced jejunal perforation, peritoneal leakage, and subcutaneous leakage. Tube induced jejunal perforation is prevented by using soft rubber tubes designed for enterostomy feeding; not high density polyethylene plastic tubes. Peritoneal leakage is prevented by paying close attention to include a 360 jejunal-abdominal wall pexy. Subcutaneous leakage is prevented by securely fixing the tube to skin. Questions
Table 1: Formulas used to calculate basal and maintenance energy requirements for dogs and cats* Calculate basal energy requirement (BER) Animals less than 2 kg body weight: 70 x body weight (kg) 0.75 = BER (kcal/day) Animals more than 2 kg body weight: 30 x body weight (kg) + 70 = BER (kcal/day) Calculate maintenance energy requirement (MER)
Factor chosen X BER = MER Calculate volume of formula required (See Table 2 and 3 for formula composition) MER ÷ kcal/ml = mls of formula per day Calculate protein requirement
Protein requirement chosen (g/100kcal) X MER (100 kcal/day) = Protein requirement (g/day) Calculate needed protein supplementation if required Protein content (g/ml) X mls of formula per day = protein provided (g/day) Protein requirement (g/day) - protein provided (g/day) = supplemental protein required (g/day) Supplemental protein required (g/day) ÷ 0.76 g protein/g of ProMod = g of ProMod per day *Data in Table 2 and 3 should be used when calculating energy requirements Table 2a: Blenderized homemade diets for dogs and cats Liquid diet for dogs and cats Ingredients: Nutrient Availability: 1.0 kcal/ml Liquid diets for cats Ingredients: Nutrient availability: 1.1 kcal/ml 3 ounces egg yolk, strained baby food 3 ounces water, 1 tsp cooking oil, 1 tablespoon corn syrup Nutrient availability 1.5 kcal/ml Table 2b: Blenderized prescription diets for dogs and cats and their composition
1/2 can is equal to 224 grams º3/4 cup is equal to 170 ml §1 - 1/4 cup is equal to 284 ml Preparation technique: Ingredients: mix the appropriate quantity of each ingredient (see Table 2b) Preparation: blend at high speed for 60 seconds strain twice through kitchen strainer (1 mm mesh) Advantages: provides all required nutrients, low cost, protein content, branched chain amino acid content, normal stool consistency, manageable viscosity for 8 French catheter or larger Disadvantages: cannot be used if feeding tube has a smaller than 8 French lumen diameter Table 3a: Commercially available polymeric diets and their composition*
Table 3b: Commercially available monomeric diets and their composition*
*These figures should be used for energy requirement calculations in Table 1. Nutritional Management
Key Points
Malnutrition is defined as the progressive loss of lean body mass and adipose tissue due to inadequate intake of or increased demand for protein and calories. Hyperalimentation is the administration of adequate supplies of nutrients to patients with malnutrition or those suspected of developing malnutrition. Enteral hyperalimentation is the provision of nutrients via a functional gastrointestinal tract. Parenteral hyperalimentation (i.e. total parenteral nutrition - TPN) is the provision of nutrients intravenously. Nasoesophageal tube feeding is performed by placing a tube through the nares and into the mid-esophagus. A nasogastric tube enters the stomach. A pharyngostomy tube is placed through an incision in the pharynx and into the midesophagus. An esophagostomy tube is placed through an incision in the left or right midcervical region and enters the midesophagus. A gastrostomy tube is placed through an incision in the left flank and enters the lumen of the stomach. Gastrostomy tubes are placed percutaneously with or without an endoscope or surgically via laparotomy. A gastroduodenostomy tube is inserted through the lumen of a previously placed gastrostomy tube and endoscopically directed into the duodenum. A jejunostomy (i.e., enterostomy) tube is placed via laparotomy. The tube is placed through an incision in the body wall and enters the lumen of the jejunum. General considerations and clinically relevant pathophysiology The possible consequences of patients with malnutrition include organ and muscle atrophy, impaired immunocompetence, ineffective wound healing, anemia, hypoproteinemia, decreased resistance to infection, and death. It is apparent from these complicating factors that patients with malnutrition should have some form of nutrient supplementation during the specific treatment of their underlying disorder. Etiology A variety of disorders may result in malnutrition including starvation, anorexia, malabsorption, severe trauma, surgical stress, sepsis, large surface area burns, and various types of malignancies. In addition, surgical procedures and postsurgical complications, as well as being unable to take nutrients orally in the immediate postoperative period (5 to 7 days), create an increased metabolic demand for protein and calories. Diagnosis Clinical Presentation Signalment - There is no age, sex, or breed predisposition for patients with malnutrition. It is commonly seen in animals with severe illness (i.e., 25 - 65% incidence in veterinary practice). History - Diagnosis of malnutrition can be accomplished by a history of 3 or more of the following criteria: 1) weight loss of greater than 10% normal body weight, 2) anorexia or hyporexia (i.e., suboptimal intake of nutrients) for greater than 5 days or an expected decrease in nutrient intake of greater than 5 days, 3) increase nutrient loss (i.e., vomiting, diarrhea, severe wounds/burns), 4) increased nutrient needs (i.e., trauma, surgery, infection, burns, or fever), 5) history of chronic illness, or 6) serum albumin concentration less than or equal to 2.5 g/dl. Physical Examination Physical examination may reveal poor hair coat, pressure sores or nonhealing wounds, tissue wasting, skeletal muscle atrophy, and emaciation. Additional physical findings will vary depending upon the specific cause of malnutrition. Radiography Thoracic and abdominal radiographs of malnourished patients are generally nonspecific. Occasionally, imaging techniques reveal an underlying cause for the patients hyporexia, anorexia, or emaciation (e.g., intestinal obstruction, abdominal mass, thoracic mass) Laboratory Findings Biochemical changes in patient's with malnutrition may include, hypoproteinemia/ hypoalbuminemia, anemia, hypoglycemia/ hyperglycemia, and hyperlipidemia. Other changes may be related to the specific underlying cause of the malnutrition. Treatment Objectives for treatment of malnourished patients include: 1) identify the cause of malnutrition, 2) treat the cause, and 3) provide complete nutrient supplementation. Objectives for preventing malnutrition in hospitalized patients include: 1) predict patient susceptibility for developing malnutrition (e.g., prolonged postoperative anorexia, early stages of a potentially chronic disorder) and, 2) begin nutrient supplementation before nutrient depletion can occur. Specific treatment is dependent upon the patients calculated energy needs, diet chosen, and route of administration selected (i.e., enteral vs parenteral). Calculate Energy Requirement A patient's basal energy requirement (BER) is calculated based on body weight; maintenance energy requirement (MER) is calculated based on BER and the number and severity of clinical problems (i.e., cage rest, postsurgical, trauma, cancer, sepsis, or major burn). These calculations are performed using specific patient data and formulas in Table 1. Enteral Diets The ideal enteral diet should be well tolerated, readily digested and absorbed, contain essential nutrients, be readily available and inexpensive, have a long shelf life, and be easy to use. Generally, diets should be isotonic (i.e., approximately 300 mOsm/L), have a caloric density of approximately 1.0 kcal/ml, include fiber at 1.0 - 1.5 g/100 kcal, provide approximately 16% of total calories as protein (i.e., protein content of at least 4.0 g/100 kcal), and provide approximately 30% of calories as fat. Polymeric diets Table 4 Nutrient profile:
Monomeric diets Monomeric diets are generally composed of crystalline amino acids as the protein source, glucose and oligosaccharides as the carbohydrate source, and safflower oil as the essential fatty acid source, generally have a twice normal osmolality, can be used in patients with primary gastrointestinal disorders (i.e., short bowel syndrome, inflammatory bowel disease, pancreatic exocrine insufficiency), and are expensive to use. The most commonly used commercially available monomeric diet is Vivonex HN; its composition is listed in Table 3. blenderized diets The most cost-effective, well-balanced diets for enteral administration are those blenderized from prescription pet food or homemade diets. Caloric density and protein content vary with the diet chosen. Examples of blenderized diets and their composition are given in Table 2. Blenderized diets can reach a consistency capable of passing through a size 8 French diameter tube or larger. Use of a commercially available liquid diet is recommended when feeding through smaller diameter tubes (i.e., size 3- to 5-French diameter). commercial diets Commercial polymeric diets are available with a variety of osmolalities, caloric densities, and compositions. Examples of commonly used commercial polymeric diets and their compositions are listed in Table 3. These formulas are indicated for malnourished patients with intact digestive and absorptive function or suspected food allergy. In addition, commercial formulas should be used in patients that must be fed through small diameter tubes (i.e., nasoesophageal, nasogastric, gastroduodenostomy, and jejunostomy feeding tubes). Parenteral Diets Diets available for total parenteral nutrition (TPN) should have a composition that meets the protein, carbohydrate, and fat maintenance requirements of dogs and cats (Table 1). The patient's caloric needs are calculated as described in Table 1. Parenteral formulations are generally designed specifically for each patient, however most solutions have the nutrient profile listed in Table 4. The formulation for central venous delivery is generally 8.5% amino acids with electrolytes (protein source), 10 to 20% lipids (fat source), and 50% dextrose (carbohydrate source). B-complex vitamins should be added at 1 - 2 ml per liter. Total Parenteral Hyperalimentation advantages: It has been well established that total parenteral nutrition (TPN) can adequately supply protein and calories to achieve nitrogen balance, accelerate wound healing, and improve patient recovery from severe protein calorie malnutrition in dogs and cats. disadvantages: However, this technique is fraught with many problems, including catheter management (i.e., sterile placement, maintaining sterility of catheter entrance, routine changing of infusion sets), expensive equipment (i.e., infusion pump), expensive feeding formulas, technical problems (i.e., constant patient monitoring during administration, diet preparation and storage), and sepsis. Also, it has recently been shown that if the gastrointestinal tract is not adequately stimulated by direct contact of nutrients or indirectly by hormonal or neurovascular mechanisms, atrophic changes in the intestine and pancreas will occur. Moreover, intestinal mucosal compromise will predispose to bacterial translocation into the portal circulation leading to possibly sepsis. These problems make total parenteral hyperalimentation an impractical, less desirable procedure than enteral hyperalimentation. indications: TPN is indicated in patients with an inability to absorb enterally administered nutrients (i.e., massive small bowel resection, impaired small intestinal motility or absorption, severe diarrhea, and intractable vomiting), severe prolonged pancreatitis, and severe malnutrition in the face of a nonfunctional gastrointestinal tract. technique: Tranquilize or anesthetize the patient and insert 16 gauge X 18-cm single lumen silicone elastomer catheter in the right or left external jugular vein. Position the catheter tip in the cranial vena cava and create a subcutaneous tunnel such that the catheter hub emerges on the dorsum of the neck. Anchor the catheter to the vein, subcutaneous tissue along the tunnel, and skin at the exit point with 4-0 or 5-0 nonabsorbable monofilament suture. Attach an extension set to the catheter hub and bandage the catheter in place with sterile gauze, conforming gauze, and self adherent wrap. Flush the catheter with 0.9% sterile saline to which 1 IU/ml of heparin was added. Begin administration of the predetermined nutrient formulation based upon calculations described above and in Tables 1 and 4 using an infusion pump. As a general rule, administer 50% of the calculated nutrient requirements the first day and 100% the second day. Evaluate serum electrolytes, glucose, total protein, serum lipids, PCV, and BUN daily. Measure body weight and temperature twice daily. Remove the neck bandage every 2 days and clean the catheter entrance site with povidone iodine solution, change the extension and administration sets, and apply a new bandage. complications: Complications associated with TPN include catheter kinking and displacement, phlebitis and thrombosis, sepsis, hyperglycemia, hyperlipidemia, azotemia, and electrolyte imbalances. Enteral Hyperalimentation advantages: Enteral hyperalimentation is a practical, safe, easy, economic, physiologic, and well-tolerated technique with minimal morbidity; however, it requires a functional gastrointestinal tract. It is the preferred method to efficiently achieve nitrogen balance and accelerate wound healing. Simply put, "If the gut works, use it." indications: Enteral hyperalimentation is indicated in any animal with overt or impending protein-calorie malnutritio, in which the gastrointestinal tract is functional. Examples include patients in a hypermetabolic state (e.g., severe burn, sepsis, postsurgical stress, trauma, cancer); patients with chronic anorexia/malnutrition, as evidenced by > 10% loss of normal body weight and hypoalbuminemia; postoperative patients in whom 5 to 7 days of anorexia is anticipated (e.g., oral, pharyngeal, esophagogastric, duodenal, pancreatic, or biliary tract surgery); postoperative cancer patients, particularly if chemotherapy is instituted; and patients with a mental status that prevents adequate self-feeding (e.g., head trauma, brain surgery). In virtually any situation in which the clinician has diagnosed protein-calorie malnutrition or can predict its occurrence, enteral hyperalimentation should be considered. contraindications: Enteral hyperalimentation may be contraindicated in several situations. It has been suggested that infusion of nutrients into the duodenum and jejunum acts as a direct stimulus to pancreatic exocrine function. This fact may preclude the use of enteral hyperalimentation in the initial management in patients with pancreatitis. In addition, patients with adynamic ileus, small bowel obstruction, severe intrinsic small bowel disease (e.g., inflammatory bowel disease, diffuse intestinal lymphosarcoma), persistent vomiting or diarrhea, or severe malabsorption should have nutrients delivered by routes other than the gastrointestinal tract. Feeding Methods determine caloric needs determine rate and volume Once the number of calories needed to meet the patient's total caloric requirement has been calculated (see Tables 1,2, and 3), the rate and volume of feeding is determined. Rate and volume are generally based on the route of administration (e.g., oral, nasogastric/ nasoesophageal, esophagostomy, pharyngostomy, gastrostomy, or jejunostomy). Feeding into the stomach When feeding directly into the stomach (i.e., oral, nasogastric/ nasoesophageal, esophagostomy, pharyngostomy, or gastrostomy), the quantity of diet fed is determined by the patient's stomach capacity. In normal dogs and cats, stomach capacity is approximately 80 cc of fluid per kg of body weight. However, anorexic patients can accommodate only 30 to 40 cc of fluid or liquid diet per kg of body weight when feeding begins. A gradual increase in volume over a two to three day period will generally allow the stomach to accommodate larger volumes of nutrients. A minimum of three feedings daily should be used, however if vomiting and abdominal distention occur, the volume should be reduced and the number of feedings per day increased. Feeding into the small intestine When feeding into the small intestine (i.e., gastroduodenostomy or jejunostomy), rate and volume of diet must be carefully regulated to avoid overdistension. Each patient is unique in the amount of fluid the small intestine will accommodate; therefore, a guideline for feeding via jejunostomy tube is outlined below:
Signs suggestive of overfeeding are vomiting, diarrhea, abdominal distention, and cramping (i.e., abdominal pain). Diluting diet concentration and decreasing the rate and volume of administration generally solve these complications. General complications of tube feeding: Three types of complications can occur during the course of enteral hyperalimentation: mechanical, gastrointestinal, and metabolic. Mechanical complications include inadvertent tube placement in the trachea (i.e., nasogastric/ nasoesophageal, esophagostomy, pharyngostomy) or peritoneal cavity (i.e., gastrostomy, gastroduodenostomy, jejunostomy), gut perforation by the feeding tube (i.e., gastroduodenostomy, jejunostomy), regurgitating or vomiting the tube (i.e., nasogastric, esophagostomy, pharyngostomy), esophageal irritation (i.e., nasogastric/ nasoesophageal, esophagostomy, pharyngostomy), infection at the tube exit site, occlusion with diet, or tube removal by the patient. Inadvertent placement of feeding tubes in the trachea or peritoneal cavity can be prevented by careful attention during tube placement. A small amount of sterile aqueous contrast material should be injected through the feeding tube and an x-ray taken if there is any question of tube location. The possibility of gut perforation can be virtually eliminated by the use of small bore silastic or soft rubber gastroduodenostomy and jejunostomy feeding tubes. Premature tube removal by the patient can be prevented by use of an adequate mechanical restraint device (i.e., bandaging and Elizabethan collar) and secure attachment of the tube to its exit site (i.e., Chinese finger-trap suture technique). Patient tolerance has been enhanced by the use of appropriate size soft rubber feeding tubes. Esophagitis secondary to nasogastric/ nasoesophageal, esophagostomy, and pharyngostomy tube placement has been reported; however, the use of silastic or soft rubber (i.e., polyvinyl) feeding tubes prevents esophageal irritation. Also, midesophageal placement effectively eliminates reflux esophagitis. Infection at the tube exit can be prevented by proper tube management. The area should be kept clean and covered with a bandage. Care should be taken when feeding the patient to keep diet formula from contaminating the exit site. Rhinitis secondary to nasogastric/ nasoesophageal tube placement can be prevented by use of small bore soft rubber feeding tubes. Small and large diameter feeding tubes may become occluded with diet. This problem is best prevented by using a commercial liquid diet rather than a blenderized diet in small bore feeding tubes (i.e., 3 - 5 French). Taking care to flush diet out of the tube when feeding is complete and capping the tube to maintain a column of water will help prevent gastrointestinal reflux and tube occlusion. If a tube becomes occluded, the use of a carbonated liquid (i.e., sparkling water, cola) can be infused into the tube. It is felt that the effervescence of the liquid will help encourage removal of clogged material. If this is unsuccessful, tube replacement may be necessary. Gastrointestinal complications include vomiting, cramping, abdominal distention, and diarrhea. The most common causes are feeding too rapidly, feeding too large a volume, and feeding diets with high osmolality. Treatment is directed at decreasing the rate and volume fed or diluting the diet to a more acceptable osmolality. Metabolic complications: Hyperglycemia secondary to rapid absorption of glucose is the most common metabolic complication; however, it rarely occurs in veterinary patients. Insulin may be used to control hyperglycemia. Dosage rates are: Dog - 0.5 to 1 IU/kg NPH insulin subcutaneously Cat - 0.25 IU/kg NPH insulin subcutaneously Hypophosphatemia may develop subsequent to enteral alimentation in severely debilitated cats. Signs associated with hypophosphatemia include hemolytic anemia and neurologic signs. The cause is hypothesized that cats in a state of chronic malnutrition are phosphorus depleted despite normal serum phosphorus levels. Feeding via enteral alimentation stimulates insulin secretion and intracellular phosphorus and glucose for glycolysis. Phosphorylation of ADP to ATP results in further phosphorus depletion resulting in hypophosphatemia. Phosphorus levels should be monitored in cats requiring alimentation. In most instances, complications can be prevented by proper tube placement technique, use of appropriate diameter soft rubber feeding tubes, use of proper diets, carefully calculated feeding schedules, and proper tube management during and between feedings. Questions
Split-shot wound management Key Points
Applied Anatomy: Skin is made up of several layers that collectively form a complex organ system. Skin is not capable of regeneration. One method of getting 'more' skin for wound coverage is encouraging local skin to undergo intussusceptive growth. This can be accomplished by applying tension to local skin around the wound. If tension is constant, skin layers will accommodate the increase tension by becoming thinner thus allowing the skin to 'streach'. Anesthesia: Patients undergoing split-shot wound management should be placed under general anesthesia. Technique: Positioning: Patients are positioned with the wounded area uppermost. Patient preparation: Wounds identified for split-shot wound management should be treated as an open wound until there is evidence of a healthy granulation tissue bed. Routine aseptic preparation of the local skin is performed. Special instruments and suture: Metalic split-shot (i.e., other than lead) can be purchased at any local sporting goods or fishing store. Split-shots are placed in a cold sterilization media for an appropriate time period and thoroughly rinsed prior to use. Monofilament nonabsorbable suture with a swaged-on taper needle, size 00 to #1 depending upon location and size of wound is recommended. A sterile rubber bumper is fashioned from a feeding tube or catheter. Split-shot technique: The wound and surrounding skin are prepared for aseptic surgery. Two bumpers are created by cutting one 1/2 inch piece off the flanged end of a 20 French feeding tube or catheter. This segment of tube is then split in two. An appropriate size monofilament nonabsorbable suture is selected. The skin edges are gently undermined being careful not to trim the wound edge. The swaged-on needle is placed through the rubber bumper and enters the wound at the commisure. The wound edges are then sutured using a simple continuous pattern. Care is taken to engage the needle in the tough collagen laden subcutaneous tissue. Patients with thin subcutaneous tissue (i.e., cats, small dogs, areas of thin skin) may require penetration of skin instead of subcutaneous tissue. Once the entire length of the wound has been sutured, the suture is passed out through the skin of the remaining commisure of the wound. Knots are not tied in either end of the suture. Gentle traction is placed on the exiting ends of the suture until mild tension is placed on the wound edges and local skin. A split-shot is placed on each end of the exiting suture against the bumper. The split-shot is then gently but firmly clamped against the suture; this maintains tension on the skin edges and local skin. The wound is bandaged, an Elizabethan collar placed, and the patient confined to a cage. Each day the bandage is removed, the ends of the suture gently pulled and a split-shot is placed between the bumper and the original split-shot. Daily tension is performed without the need for general anesthesia or sedation. Skin may be responsive to tension for 7 to 10 days. When the wound is closed to your satisfaction, the suture and bumpers are removed. The remaining wound is bandaged only if it requires further protection. Tie-over bandage Key Points
Wound Management: The area should be clipped and cleaned as soon as possible to provide a clean environment beneath the bandages that will eventually be applied. Sterile, water soluble gel placed on the wound is a convenient means of temporary wound protection. Dried blood and debris should be removed from the surrounding skin with antiseptic soap, using care to avoid contact between the soap and exposed tissues which can result in lipolysis and tissue damage. The primary goal of wound management is to decrease bacterial numbers and debris and enhance the animal's defense mechanisms (i.e., debridement). Gross particulate matter, hair, etc. should be removed manually from the wound. Lavage is beneficial in further decreasing infection-promoting debris and bacteria. Saline is indisputably the ideal lavage solution, although dilute chlorhexidine (0.05 to 0.005%), or povidone-iodine (0.01%) may be used. The effectiveness of lavage is dependent upon volume and pressure. Studies have shown that high pressure (25-60 psi) is superior to low pressure (0.5-5.0 psi) when wounds are only lavaged one time. Medium pressure, which has also been shown to be beneficial can be generated using an 18 gauge needle and large syringe (35-60 ml). Surgical debridement of necrotic-appearing tissue and embedded foreign material limits nutrients for bacterial growth and enhances the animal's local defense mechanisms. Open Wound Management: Open wound management allows optimal drainage and daily inspection, debridement and lavage of tissues. Following surgical excision of necrotic tissue, etc., continued mechanical debridement can be performed using an adherent dressing (wet-to-dry, dry-to-dry, or wet-to-wet). Wide-mesh gauze sponges are ideal for adherent bandages. The type of dressing used depends on wound conditions. Wet-to-dry dressings can be used for wounds with necrotic tissue, foreign matter and viscous exudate. The wet dressing dilutes the exudate and allows absorption. As the dressing dries, necrotic tissues adhere to the gauze and are removed with the bandage. Dry-to-dry dressings have similar indications as wet-to-dry except without the presence of viscous exudate. Wet-to-wet dressings are indicated when viscous exudate is present without necrotic tissues. The contact adherent layer should be covered by an absorbent outer layer. Once necrotic tissues have been removed and granulation tissue begins to form, adherent gauze should be replaced with nonadherent pads (telfa). Second Intention Healing: Second intention healing occurs by formation of granulation tissue, wound contraction and epithelialization. The advantages of this process are drainage remains optimal, wound infections are rare and the time and expense of surgery is avoided. However, second intention healing may cause disfigurement or loss of function due to wound contracture, and the epithelium formed may be easily disrupted. Tie-Over Bandage: Indications: Large surface area wounds (i.e., abdomen, thorax, back, neck) or wounds in 'difficult-to-bandage' areas (i.e., tail, perineum, head, paraprepucial,proximal extremeties) may not be amenable to routine bandaging techniques. These areas generally lend themselves nicely to placement of a tie-over-bandage. Technique: The wound bed is prepared as described above. Several # 0 or #1 monofilament nonabsorbablesuture loops are placed in the skin on the periphery of the wound. Loop sutures are generally placed 360o around the wound and spaced 2 or 3 cm apart. Appropriate wound covering materials are placed in the wound bed (i.e., wet to dry, gauze, telfa, etc) and a sterile laparotomy pad placed on top to provide protection to the wound.Several lengths of 1/4 inch or 1/2 inch umbilical tape are passed through the loops of suture, over the laparotomy pad and through the suture loop on the opposite side of the wound. The umbilical tape passes over the wound mutiple times to hold the laparotomy pad in place (an therefore the wound covering materials). Enough traction is placed on the suture loops to place mild tension on the skin edges of the healing wound. This bandage is easily removed and replaced for ease of bandage change. Management of Cystic and Urethral Calculi in Cats
Key Points
Diagnosis Clinical presentation: Signalment: There is no age, sex or breed predisposition. History: Patients generally present with a history of urinary obstruction and/or signs of urinary tract infection. Common complaints include difficulty urinating, straining to urinate, hematuria, blood tinged urine in the litter pan, and/or a distended abdomen. Patients that present several days after complete obstruction may have a distended and painful abdomen and a history of anuria. These patients may be so compromised that they present in shock. Clinical signs: The most frequently reported clinical signs in patients with cystic and urethral calculi include unproductive straining to urinate, blood tinged urine seen in the litter pan, hematuria, and/or polakiuria. Severity of clinical signs may vary with the degree of urethral obstruction and duration of obstruction prior to presentation. Patients with complete obstruction for several days may show signs of post-renal azotemia (i.e., severe depression, recumbant, shocky). Physical examination: Abdominal palpation may reveal a full urinary bladder; occasionally, calculi within the bladder may be palpable. Patients with severe clinical signs (i. e., presented several days after complete obstruction) may show azotemia, shock, and/or severe depression. Abdominal palpation generally reveals a large, turgid urinary bladder and may result in discomfort to the patient. Laboratory findings: Results of a complete blood count and serum chemistry profile are generally normal in patients presenting acutely; urinalysis may show evidence of urinary tract infection and and/or crystalluria. Patients presenting after several days of complete obstruction may have significant changes in their biochemical profile including increased BUN, increased creatine, metabolic acidosis, and severe electrolyte abnormalities. Urine is generally grossly hemorrhagic and urinalysis may show signs of urinary tract infection and crystaluria. Radiography: Survey radiographs may show presence of radiodense calculi in the urethra and/or urinary bladder as well as a distended urinary bladder. Occasionally, radiolucent calculi occur and can only be visualized using retrograde contrast cystourethrography. Careful evaluation of the kidneys and ureters should be done to rule out renal and ureteral calculi. Ultrasonographic examination of the bladder, ureters, and kidneys may be helpful in diagnosis of cystic, ureteral, or renal calculi. Differential diagnosis: Any disorder causing urinary obstruction, including urethral neoplasia, granulomatous urethritis, urethral stricture, and urethral trauma. Definitive diagnosis is based on clinical signs, inability to pass a catheter, and evidence of calculi on survey or contrast radiographs. Medical Management: Immediate care: In animals with complete obstruction of a duration long enough to cause azotemia, temporary urinary diversion is provided by performing a prepubic cystostomy (see technique described below) or frequent cystocentesis (i.e, tid to qid). Azotemia is treated with crystalloid IV therapy prior to calculus removal. Calculus removal: Retrograde hydropulsion: This technique should result in a 80-85% success rate of retropulsing urethral calculi into the urinary bladder! Thoroughly mix 20 cc of sterile saline and 5 cc of Surgilube or KY Jelly in a 35 cc syringe and attach the syringe to a 3.5 - 5.0 French soft rubber catheter. Anesthetize the animal, extrude the penis and pass the lubricated urinary catheter in the urethra, up to and against the calculus. Place a dry gauze sponge around the extruded tip of the penis and occlude the penis around the catheter by squeezing it with thumb and finger. Using a back and forth action on the catheter, simultaneously inject the saline/lubricant mix under extreme pressure. a) During injection, the calculi and urethra are lubricated by the saline/lubricant mix while the viscosity of the mixture (i.e., KY jelly and saline) encourages the calculus to dislodge and become retropulsed into the urinary bladder. b) This technique is attempted, and generally successful, regardless of how many stones are in the urethra and no matter where they are lodged. If the above technique fails, use a stiffer catheter (i.e., open or closed ended Tom cat catheter) and repeat the above maneuvers. Use care when manipulating the catheter against the stone. Surgical Treatment: The objective of surgical treatment is to remove all retropulsed calculi from the urinary bladder and any remaining urethral calculi that were unable to be retropulsed. Bladder calculi are removed via cystotomy , urethral calculi are removed via urethrotomy, and patients that are frequent stone formers may benefit form a permanent urethrostomy to allow continual passage of small urethral calculi. Preoperative management: Patients that present acutely can be anesthetized immediately and retropulsion attempted (see above described technique). If urinary tract infection is suspected, preoperative treatment with antibiotics may be instituted. Patients that present after several days of complete obstruction should be treated medically until the azotemia resolves, blood gas abnormalities resolve, and electrolytes return to normal. The patients electrocardiogram should be monitered if hyperkalemia is present preoperatively. Medical treatment may consist of intravenous fluids, systemic antibiotics, continuous ECG monitoring, and bladder decompression. Bladder decompression may be accomplished via multiple cystocentesis (i.e., tid or qid), or placement of a antepubic cystostomy tube (described in detail below). Anesthesia: Routine general anesthesia is performed in patients that present acutely without signs of azotemia. Azotemic, shocky patients with moderate to severe biochemical abnormalities should be treated as described above until these abnormalities return to normal. Surgical anatomy: The male feline penile urethra consists of urethral mucosa (i.e., urothelium) surrounded by corpus cavernosum urethra, which is in turn surrounded by tunica albuginea. Because of the fluid filled corpus cavernosum urethra (blood) and the tough fibrous connective tissue tunica albuginea, the urethra can withstand tremendous pressure (e.g., as with aggressive retropulsion) without the fear of urethral rupture. The urinary bladder consists of the following layers; serosa, muscular, submucosa and mucosa. The bladder is lined with transitional epithelium. Positioning: Patients are positioned in dorsal recumbancy for retropulsion, cystostomy tube placement, and cystotomy. Surgical technique: The surgical techniques vary depending upon the procedure chosen, and are described in detail below: Retropulsion: The technique for retropulsion of urethral calculi is described above in medical management. Percutaneous cystostomy tube placement: Occasionally, it may be necessary to perform a percutaneous antepubic cystostomy to decompress the urinary bladder whilst treating a severely azotemic patient until they become a better anesthetic and surgical risk. The patient is sedated and placed in dorsal recumbancy. A 3-4cm incision is centered between the umbilicus and pubis. Subcutaneous tissues are disected to expose the ventral midline (i.e., linea alba). A 2-3 cm incision is made in the linea alba and the bladder wall located. A 12 - 14 French Foley catheter is advanced through a skin incision 2-3 cm lateral to the abdominal incision, tunneled in the subcutaneous tissue and brought into the abdominal cavity at a location just lateral to the midline abdominal incision. A pursestring suture is placed in the bladder wall at the proposed site of Foley catheter placement with 3-0 monofilament absorbable suture. A 1cm incision is made into the bladder lumen and the Foley catheter advanced. The pursestring suture is carefully tightened to create a water-tight seal, but not to tight as to create bladder wall necrosis. The bladder wall is pexied to the abdominal wall at the point of entry of the Foley catheter with 3-0 monofilament absorbable suture in a simple interrupted pattern. The abdominal wall is closed in a routine fashion. The cystostomy catheter is held in place with a chinese finger trap friction suture technique using #1 monofilament nonabsorbable suture and attached to a closed collection system to avoid urinary tract infection. The cystostomy tube remains in place until the patient is ready for definitive surgical treatment. Urethrostomy: Urethrostomy is generally performed in patients that are recurrent stone formers. It provides a permanent opening that is large enough to accommodate passage of most urethral calculi/crystals and mucoid debris. Perineal urethrostomy is the location of choice for urethrostomy in cats. It is a convienent location for surgical manipulation, the urethral diameter will accommodate passage of most urethral calculi, and there is less urine scald postoperatively. Prior to surgery a urethral catheter is passed, if possible. After a routine castration, the subcutaneous tissues are dissected to expose penile urethra. The penile urethra is disected free from surrounding connective tissue. The ventral attachment of the pelvic urethral to the pubis (i.e., ishiocavernosus m.) is identified and transected. The penile urethra is freed from its connective tissue attachments to the pelvic floor using blunt digital disceciton. The retractor penis muscle is identified on the dorsal aspect of the penis, disected from its attachment on the penis and used to develop a dorsal plane of disection to separate the pelvic urethra from its dorsal connective tissue attachments. Once the urethra is disected enough to visualize the dorsolaterally located bulbourethral glands, penile disection can stop. The penis is catheterized and the urethral orifice identified. An incision is made from the penile urethra to the pelvic urethral to the level of the bulbourethral glands. The urethral orifice at the level of the bulbourethral glands is generally large enough diameter to accept the flange of a tomcat catheter. After incision of the urethra, the glistening urethral mucosa is identified. 5-0 nonabsorbable monofilament suture with a swaged on cutting or taper-cut needle is recommended by the author. The first urethrostomy suture is placed at at the dorsal aspect of the urethrotomy incision on the right or left side at a 45o angle to include urethral mucosa and skin (suture split thickness of skin). The suture is tied leaving the end without the needle 3-4 cm long to act as a stay suture. The second suture is placed oposite the first suture and tied as described for the first. A third urethrostomy suture is placed directly on the dorsal midline to hold the dorsal margin of urethral mucosa to skin. Alternating sutures from dorsal to ventral are placed until approximately one half of the penile urethra has been sutured to skin. The remainder of the penis is amputated and the subcutanious tissue and skin are closed routinely. Fine ophthalmic instruments make tissue handling and suturing easier. Use of a magnifying loupe (about 2x) and head lamp light source enhances visualization of the urethral mucosa and facilitates accurate suturing. It is critical that the surgeon recognize glistening urethral mucosa and suture it to skin. This will decrease (or eliminate) the chance of urethral stricture. It has been shown that a continuous suture pattern incorporating the urethral mucosa and tunica albuginea (i.e., squeezes the cavernous tissue) results in less postoperative hemorrhage. Cystotomy: After successful retropulsion of urethral calculi into the bladder, the catheter used to retropulse calculi is passed into the urethra and bladder, and left in place. The catheter exiting the penis is cut. Leaving a catheter indwelled in the urethra ensures that remaining cystic calculi will not roll back into the urethra during patient transfer to the surgery suite and during patient prep. The patient is place in dorsal recumbancy with the hind legs tied gently cranially. Just prior to aseptic preparation of the abdomen a soft, 5-8 French red rubber catheter or feeding tube is placed into the prepuce and a prepucal douche is performed with 120 cc of a 0.01% solution of betadine. This aseptically prepares the penis and prepuce so they can remain in the surgical field throughout the cystotomy procedure. A caudal midline incision is made from umbilicus to pubis. The bladder is exteriorized and examined. Stay sutures of 3-0 suture are placed in the apex and neck of the bladder. A scalpel blade is used to penetrate the ventral aspect of the bladder and enter the lumen. The ventral cystotomy incision is extended with metzenbaum scissors. The bladder should be opened from apex to neck to allow proper visualization of bladder mucosa and calculi. Stay sutures are placed on each side of the incision at its midpoint to facilitate visualization of the bladder interior. Large hemostats are placed on the stay sutures to help retract the bladder margins. A cystotomy spoon is used to scoop the bladder neck for calculi. This is performed several times. When no more calculi can be removed with the spoon, digital palpation of the bladder neck is performed to identify presence of further calculi. If further calculi are palpated further attempts are made to retrieve the calculi. Once no more calculi can be spooned or palpated, the indwelling urethral catheter placed after retropulsion is removed. Next, a 3.5 - 5 French urethral catheter is placed in the penile urethra (i.e., retrograde). A dry sponge is used to grasp the extruded penis to create a water tight seal around the catheter. A 35cc syringe filled with sterile saline is injected through the catheter under moderate pressure. The stay sutures on the bladder incision are retracted to enable visualization of the bladder lumen during lavage. Suction or intermittent spooning is performed during lavage in an attempt to identify and remove any remaining stones. After several lavages and negative results in obtaining stones, the catheter is placed from the bladder to the bladder neck and pelvic urethra (i.e., normograde). Lavage is once again performed in an attempt to identify and remove any remaining stones. After several lavages and negative results, the catheter is advanced until it can be seen coming out of the penile urethra. The catheter is run back and forth in the urethra several times to ensure that there are no remaining calculi (i.e., gritty feeling while passing the catheter). Finally, a piece of bladder mucosa is excised for culture and susceptability testing. The interior of the bladder is examined for urachael diverticulm, masses, etc. and biopsied as necessary. The bladder wall is closed with 3-0 or 4-0 absorbable monofilament suture material using a swaged on taper or taper-cut needle in a simple continuous or simple interrupted appositional suture pattern. Only one layer closure is necessary. Abdominal closure is routine. Suture material/special instruments: Urinary catheters of various sizes, Foley catheter, head lamp light source, 2X loupes, ophthalmic instruments, 4-0 or 5-0 monofilament nonabsorbable suture material. Postoperative Care And Assessment: Postoperative care varies depending upon procedure performed: Percutaneous cystostomy tube: It is important to keep the percutaneous cystostomy tube attached to a closed collection device. The tube can be connected to a sterile collection bag via a sterile intravenous catheter connection set. An elizabethan collar may be necessary in some patients to prevent iatrogenic removal of the cystostomy catheter. Careful management is important to control catheter related urinary tract infection. Perineal Urethrostomy: An Elizabethan collar should be considered, especially in patients that may be prone to self-mutilation. Patients should be kept quiet and away from other animals. Prognosis The prognosis for surgical management of urethral and cystic calculi is dependant upon preoperative management of azotemic patients prior to anesthesia, success of retropulsion of urethral stones into the urinary bladder, care in removing all stones via cystotomy, and care of ensuring urethral mucosa to skin apposition during urethrostomy. Patients that have successful retropulsion of urethral calculi and do not require urethrostomy have a excellent prognosis. If careful attention is paid during cystotomy to ensure that no calculi are left behind (see discussion on cystotomy technique), the prognosis for cure is excellent. Long term prognosis is dependant on evaluaiton of calculus composition, dietary management, management of urinary tract infection, and attention to urine pH. Patients that have an elective perineal urethrostomy have a favorable prognosis if attention is paid to proper surgical technique (i.e., urethral mucosa is sutured to skin). Occasionally, chronic stone forming patients will form a calculus that is to large to pass through the urethrostomy stoma. Retropulsion of Urethral Calculi in the Dog
Introduction Uroliths are defined as calculi lodged in the urethra causing partial or complete obstruction and urethritis. Uroliths may be caused by infection, diet, or they may be metabolic. Generally, small cystic calculi migrate to the neck of the bladder during micturition and pass into the urethra. In the male, urethral calculi most commonly lodge caudal to the os penis. In the female, calculi may lodge at any location along the length of the urethra. Urethral obstruction is more common in the male than female. Clinical Signs Clinical signs include stranguria, hematuria, pollakiuria, and occasionally blood dripping from the prepuce. Patients with complete urinary obstruction may present with a painful, distended abdomen, anuria, and azotemia. The severity of signs is often dependent upon degree and duration of urethral obstruction. Diagnosis Diagnosis is generally based on suspicious clinical signs, inability to pass a catheter into the urinary bladder, and survey radiography or positive contrast retrograde urethro cystography revealing a urethral obstruction. Differential Diagnosis Diagnostic differentials include neoplasia, urethral stricture, urethritis (e.g., granulomatous), and urethral trauma Treatment Immediate care is dependant upon patient presentation and severity and duration of urinary obstruction. In animals with complete obstruction of a duration long enough to cause azotemia, temporary urinary diversion is provided by either passing a urinary catheter alongside the calculus, performing a prepubic cystostomy, or frequent cystocenteses. Treatment of azotemia with crystalloid IV therapy is performed prior to calculus removal. Retrograde Hydropulsion Removal of the urethral calculus/calculi is performed using the following technique. Following the outlined steps below will result in greater than 95% success in retrograding a severely lodged urethral calculus into the urinary bladder: A. Thoroughly mix 45 cc of sterile saline and 15 cc of Surgilube in a 60 cc syringe and attach to the largest high density polyethylene urinary catheter that will pass through the os penis (5 to 8 French). B. Anesthetize the animal, extrude the penis and pass the catheter up to and against the calculus. Place a gauze sponge around the tip of the penis and occlude the penis around the catheter by squeezing it with thumb and finger. C. Using a back and forth action on the catheter, simultaneously inject the saline/lubricant mix under pressure. a) The calculi and urethra are lubricated and the viscosity of the mix encourages the calculus to dislodge and flush into the bladder. b) This technique is attempted regardless of how many stones are in the urethra. D. If the above technique fails, place a finger in the rectum, palpate the urethra, and occlude its lumen, repeat step 3 above and when maximum pressure is exerted on the urethra by the saline/lubricant mix, suddenly release digital urethral occlusion allowing lodged calculi to flush into the bladder. E. Indwell a urethral catheter in the urethra prior to transporting the patient to surgery to ensure that cystic calculi do not migrate back into the prostatic and pelvic urethra. F. A ventral midline celiotomy and cystotomy are then performed to remove all calculi. Urethrotomy (an incision over the calculi) may be performed to remove calculi that cannot be retropulsed. It is usually performed in the prescrotal or perineal region. Urethrostomy (a permanent opening to allow calculi to pass) may be indicated in animals that are chronic recurrent calculi formers (e.g., urate calculi in Dalmatians). Scrotal urethrostomy is the technique of choice. Patient Monitoring Patients requiring a cystotomy only can be expected to pass small quantities of blood and blood clots for 2 - 3 days postoperatively. Animals presenting with complete urinary obstruction and postrenal azotemia are continued on crystalloid IV therapy until serum urea nitrogen and creatinine return to normal. Patients requiring a urethrotomy or urethrostomy may hemorrhage from the urethral stoma and is the most common immediate postsurgical complication. It generally occurs 4 - 5 days postoperatively, but occasionally will last up to 2 weeks. Mild dripping is managed with cage rest and tranquilizers to decrease blood pressure. Moderate hemorrhage is manages by mild pressure with a cold compress placed directly over the urethrostomy site. In most cases it is necessary to apply an Elizabethan collar to prevent self-mutilation. |
