Chapter 86

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1466 PART 5 ■ Anesthetic, Surgical, and Interventional Procedures: Considerations TABLE 86-21. Typical Management of a Neonate Presenting With Omphalocele Symptoms Preoperative investigations Monitoring Suggested anesthetic and recommendations Recommended Examinations and Management 30–40% have congenital heart defects. Midline defects 1. Nearly all patients have paralytic ileus. Nasogastric tube allows decompression of stomach 2. Chest radiograph and echocardiography 3. Routine laboratory with special attention regarding electrolyte status 4. Make sure the patient is not hypovolemic 5. Blood type and compatibility test; Order 1 unit blood and 1 unit plasma 1. Routine monitoring healthy neonates 2. Invasive blood pressure monitoring and Foley catheterization 3. If available, monitor stomach or bladder pressure if primary closure of the defect is expected. Pressures 20 mmHg significantly reduce cardiac output and hepatic blood flow 205 1. No premedication, I.V. atropine (10 g/kg), preoxygenation 2. Aspirate nasogastric tube and perform a rapid sequence induction 3. Closure of a minor defect and creating a “tent” are usually uneventful; primary closure of a larger defect is accompanied by a number of problems 4. Maintenance depends on hemodynamic stability. Inhalational or opioid technique indicated. Pain relief can be provided with epidural which also provide abdominal wall muscle relaxation. Remember that high intra-abdominal pressure reduces clearance of local anesthetics. Lidocaine provides better muscle relaxation than bupivacaine and plasma levels are easier to monitor 5. Large insensible water loss (often in excess of 10 mL/kg/h). Volume replacement with albumin or plasma. Fluids must be warmed. Overhead or convective warming are needed 6. Despite adequate volume replacement hypotension may persists and dopamine infusion is often needed to achieve normal blood pressure and urine output (severe presentation) 7. Overenthusiastic attempts by the surgeon to close the defect inevitably cause a decrease in blood pressure and cardiac output and may interfere with ventilation. The surgeon must be alerted and use an alternative approach (Gortex patch, Silastic tent) 8. Postoperative ventilation support might be needed in the more severe presentation Intestinal Obstruction This is most commonly caused by single or multiple atresia of the small intestine. The symptoms present somewhat later than duodenal obstruction and an abdominal radiograph will show classic signs of mechanical ileus. If diagnosed properly patients rarely deteriorate regarding fluid and electrolyte balance to any significant degree. The main steps of anesthetic management are summarized in Table 86–24. Malrotation of the Gut In this condition, the mesentery of the gut has failed to develop in a normal way. Instead of attaining the normal broad base of the mesenterium, reaching from the ligament of Treiz to the right iliac fossa, rotation of the gut will be incomplete, leaving the gut sus - pended in a mesenterial base which is very narrow at the root of the superior mesenteric vessels. This sets the stage for the possibility of rotation of the gut around its own base with concomitant strangula - TABLE 86-22. Typical Management of a Neonate Presenting With Pyloric Stenosis Symptoms Preoperative investigations Monitoring Suggested anesthetic and recommendations Recommended Examinations and Management Forceful projectile vomiting after feeding. Look for signs of dehydration. Palpable olive-like resistance to the right in the epigastrium. Ultrasonographic examination will usually provide the final diagnosis 1. A nasogastric tube should be passed at the same time the diagnosis is made 2. Make sure signs of dehydration are not present. Check or inquire about urine output during the last couple of hours. Inspect the diaper 3. Routine laboratory with special attention regarding electrolyte and acid-base status. Sodium, potassium, and chloride values should be normal. Do not accept base excess values above 2 Routine monitoring 1. No premedication, I.V. atropine (10 g/kg), preoxygenation 2. Reduce stomach volume and content by aspirating the nasogastric tube 3. Rapid sequence induction. Maintenance with volatile agents. Relaxation indicated during pyloromyotomy to avoid duodenal tears 4. Infiltration of the wound edges with a long acting local anesthetic (bupivacaine or ropivacaine) will ensure high quality pain relief in the immediate postoperative period. Narcotics should not be used for risk of postoperative hypoventilation or apnea
TABLE 86-23. Typical Management of a Neonate Presenting With Duodenal Atresia Symptoms Preoperative investigations Monitoring Suggested anesthetic and recommendations CHAPTER 86 ■ Management of the Neonate: Anesthetic Considerations 1467 Recommended Examinations and Management Classic signs of intestinal obstruction. An abdominal radiograph is usually diagnostic due to the presence of the “double bubble” signs, which consists of two large air-filled structures (stomach and proximal duodenum separated by the pylorus) in the epigastric region 1. Check the presence of a nasogastric tube 2. Make sure signs of dehydration are not present 3. Routine laboratory (electrolyte and acid-base status) 4. Blood type and compatibility test and order 1 unit blood 1. Routine monitoring 2. Invasive blood pressure monitoring 1. No premedication, I.V. atropine (10 g/kg), preoxygenation 2. Try to empty the stomach by aspirating the nasogastric tube 3. Rapid sequence induction 4. Since the patient will be subjected to fairly extensive upper abdominal surgery a continuous epidural block supplemented by a light volatile agent maintenance anesthetic is often a good choice 5. Central venous catheter placement might be mandatory, not for anesthetic purposes but for postoperative total parenteral nutrition since enteral nutrition will usually be delayed tion of the mesenteric vessels. This will lead to an ischemic paralysis of the gut which does not have to have any mechanical obstructive component associated. If prolonged the gut ischemia will cause a combined situation of ileus, hypovole mia, and sepsis/ endotoxemia from translocation of intestinal bacteria. Thus, these patients will often present in an unstable state. However, this represents one of the very few real emergen cies within neonatal surgery, since failure to treat this condition rapidly can cause severe harm to the patient. Either necrosis of almost the entire small intestine will occur and leave the patient and the family with the lifelong problems associated with the short bowel syndrome or the condition might become fatal or require a very long period of intensive care due to overwhelming sepsis/endotoxemia. The emergency nature of this condition cannot be overemphasized and stabilization of the circulation, correction of fluid and electrolyte deficits and other necessary measures needs to be performed simultaneously with starting and maintainin the anesthetic! The main steps of anesthetic management are listed in Table 86–25. Anal Atresia This malformation should be identified as part of the routine examination of each newborn baby. The atresia can be classified as low, intermediate, or high. If an adequate fistula (most often rectovaginal fistula in females) is not present the baby will need some surgical intervention to allow reasonable drainage of the gastrointestinal tract. In the case of a low, membranous atresia definitive correction is possible but in the case of a higher atresia final repair will be deferred until later, and drainage will be accomplished by the formation of a colostomy. Since diagnosis is usually made early, the neonate will almost always be in good clinical condition for the anesthesia. TABLE 86-24. Typical Management of a Neonate Presenting With Intestinal Obstruction Symptoms Preoperative investigations Monitoring Suggested anesthetic and recommendations Recommended Examinations and Management Classic signs of intestinal obstruction. An abdominal radiograph is usually diagnostic showing traditional signs of mechanical obstruction 1. Check the presence of a nasogastric tube 2. Make sure signs of dehydration are not present 3. Routine laboratory with special attention regarding electrolyte and acid-base status 4. Blood type and compatibility test and order 1 unit blood 1. Routine monitoring. Invasive blood pressure monitoring when indicated 1. No premedication, I.V. atropine (10 g/kg), preoxygenation 2. Try to empty the stomach by aspirating the nasogastric tube 3. Rapid sequence induction 4. Since the patient will be subjected to extensive upper abdominal surgery a continuous epidural block supplemented by a light volatile agent maintenance anesthetic is a good choice 5. Contrary to duodenal atresia the surgical procedure will most often involve resection of the bowel. Due to third spacing within the mesenterium volume replacement with 5% albumin or plasma is usually required to maintain adequate intravascular volume 6. As with duodenal atresia, a central venous catheter might be mandatory for postoperative nutritional purposes (parenteral nutrition)
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Chapter 86

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