What the Anesthesiologist Should Know before the Operative Procedure
Extrahepatic biliary atresia is a progressive congenital condition that occurs as a result of an obliterative inflammatory process of unknown etiology. It is characterized by cholestasis and hepatic fibrosis and leads to cirrhosis, portal hypertension, and synthetic liver failure.
The Kasai portoenterostomy bypass is a surgical procedure performed on infants with biliary atresia. It aims to restore extrahepatic bile flow, and if successful it can lead to a 10-year survival of the native liver in about 50% of patients. Surgery involves bypassing the blocked extrahepatic bile ducts by attaching a jejunal Roux-en-Y loop to the internal hepatic ducts. In some cases the Kasai procedure may be curative; however, in most cases it is palliative, and definitive surgery for these patients would involve a liver transplant.
1. What is the urgency of the surgery?
What is the risk of delay in order to obtain additional preoperative information?
The Kasai should be performed before 12 weeks of age. Any delay is usually due to a late diagnosis rather than for medical reasons. Serious comorbidities requiring intervention before surgery are relatively rare. The clinical condition of the patient worsens over time, leading to portal hypertension and impairment of synthetic liver function.
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The Kasai may still be attempted in patients who present late. These patients will likely exhibit failure to thrive and ascites. Hypoalbuminemia, portal hypertension, coagulopathy, and anemia should be treated prior to surgery. These patients have a poorer outcome.
2. Preoperative evaluation
Cardiac abnormalities and the complications of biliary atresia should be looked for. Complications include cholangitis, ascites, hypoalbuminemia, portal hypertension, coagulopathy, anemia of chronic disease, and, rarely, hepatorenal syndrome, where there is progressive renal failure in a patient with cirrhosis of the liver.
Significant ascites may require drainage prior to anesthesia to avoid respiratory embarrassment on induction. Coagulopathy and anemia should be corrected preoperatively.
3. What are the implications of co-existing disease on perioperative care?
Twenty percent of cases of biliary atresia are associated with additional abnormalities, including heterotaxy syndrome. A left-sided SVC or bilateral SVCs may affect central line insertion. Other abnormalities include polysplenia with functional asplenia, and portal vein and gastrointestinal abnormalities, which are not usually of concern to the anesthetist. Some patients do have coexisitng congenital cardiac disease, which should be assessed and treated according to severity. A pediatric cardiologist should be consulted in the case of recognized congenital cardiac disease for assessment and management.
b. Cardiovascular system:
N/A
c. Pulmonary:
N/A
d. Renal-GI:
N/A
e. Neurologic:
N/A
f. Endocrine:
N/A
g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (e.g., musculoskeletal in orthopedic procedures, hematologic in a cancer patient)
N/A
4. What are the patient's medications and how should they be managed in the perioperative period?
Uncomplicated patients are given vitamin K preoperatively. Patients with cholangitis will be on antibiotics, usually trimethoprim, and perhaps steroids. Patients with portal hypertension may be on beta-blockers, octreotide, or somatostatin. Patients with growth failure may be on nasogastric feeds and fat-soluble vitamins.
h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?
N/A
i. What should be recommended with regard to continuation of medications taken chronically?
Patients should continue to take medications until the time of surgery. Patients on high doses of steroids may need perioperative steroids to overcome blunting of their endogenous response to the stress of major surgery. This should be done in consultation with the surgeon and a pediatric endocrinologist.
j. How to modify care for patients with known allergies
Allergy is unusual in this age group.
k. Latex allergy – If the patient has a sensitivity to latex (e.g., rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.
N/A
l. Does the patient have any antibiotic allergies – Common antibiotic allergies and alternative antibiotics
Allergy is unusual in this age group.
m. Does the patient have a history of allergy to anesthesia?
Malignant hyperthermia (MH)
Documented: Avoid all trigger agents such as succinylcholine and inhalational agents. Follow a proposed general anesthetic plan: total intravenous anesthesia with propofol ± opioid infusion ± nitrous oxide. Ensure an MH cart is available [MH protocol].
Local anesthetics/muscle relaxants
Recall that local anesthetics belong to two chemical classes (amides and esters). If a true allergy is present, it is most likely due to an ester class local anesthetic. Indeed, even in this rare situation the allergy may be from a local anesthetic metabolite such as para-amino-benzoic acid (PABA) or a preservative. If a true allergy is suspected, either a local anesthetic from another chemical class should be used or local anesthetic use should be withheld.
5. What laboratory tests should be obtained and has everything been reviewed?
Common laboratory normal values will be same for all procedures, with a difference by age and gender.
Full blood count: Exclude anemia, thrombocytopenia, and infection.
Electrolytes: Exclude significant abnormalities in a fasting infant.
Coagulation panel: Exclude coagulopathy from hepatic failure, as well as from an undiagnosed inherited coagulopathy.
Imaging: Chest x-ray and echocardiogram to exclude congenital cardiac disease.
Liver function panel: Assess severity of liver dysfunction if present.
Glucose: Exclude hypoglycemia in fasting patient with impaired liver function.
Red blood cells less than 5 days old to avoid storage lesion, and clotting products should be available for transfusion.
Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?
The procedure is performed under general anesthesia combined with either intravenous or regional analgesia. There are no data to support one technique over the other.
a. Regional anesthesia
Regional analgesia is performed after induction of general anesthesia.
Epidural analgesia is safe and effective and is used in some centers, unless contraindicated by coagulopathy, local or systemic infection, or lack of consent by parents or surgeon. Catheter placement at the thoracic level in infants can be achieved by advancing the catheter tip via the caudal or lumbar areas, or by primary placement at the thoracic level. Caudal epidurals may be less safe than site specific epidurals, as epidural veins may be enlarged in patients with portal hypertension.
Epidurograms, ultrasound, and electrical stimulation have all be used to verify catheter position in an attempt to ensure optimal epidural analgesia. The wound is usually around the T7-8 dermatomes, and so epidural tip placement should be at this level. Clearance of local anesthetic in the first 6 months of life is lower than in adults. Plasma bupivacaine levels increase over time in infants with continuous epidural infusions. Ropivacaine levels are stable or decrease over time. Therefore, ropivacaine is recommended and the duration of infusion should be limited to avoid accumulation and toxicity. Perioperative coagulopathy is rare, but confirmation or a normal coagulation profile prior to placement and removal is prudent.
b. General anesthesia
The usual issues of anesthetizing a small infant need to be considered: secure airway, neonatal ventilation strategies, difficult intravenous access and invasive monitoring, hypothermia, and hypoglycemia. Access to the patient during surgery is limited, and surgery may need to be temporarily halted during resuscitation or an emergency to allow management by the anesthetist. Avoidance of ketamine and midazolam is reasonable in view of their possible effects on cognitive development.
Intubation with atracurium or cisatracurium is the norm. A cuffed endotracheal tube may be better as retraction on the diaphragm can be significant, and ventilatory pressures may need to be high. Routine monitoring may be supplemented with intra-arterial blood pressure measurement and central venous pressure monitoring, which should be achieved via the jugular veins, rather than the femoral route. This is due to the fact that the IVC may become occluded during retraction of the liver. Analgesia can be achieved with morphine (100 to 200 mcg/kg) or fentanyl (3 to 5 mcg/kg) as required.
6. What is the author's preferred method of anesthesia technique and why?
The authors prefer to use general anesthesia and intravenous analgesia so as to avoid the potential problems associated with an epidural catheter in a coagulopathic patient. Postoperative coagulopathy is rare; however, the peak incidence is around postoperative day three when the epidural catheter is usually due to be removed. Patients are anesthetized and intubated. Large-bore intravenous access in the upper limbs is required, as despite the usual requirements for fluid, blood, and clotting products being low, they can be significant. We use an arterial line routinely. Central venous access via the SVC is placed to allow the infusion of vasopressors. Severe retraction and delivery of the liver for surgical access occludes the IVC and impedes venous return by up to two-thirds. This can be managed using vasopressors rather than volume to avoid liver capsule distention, which risks rupture and hemorrhage and avoids fluid overload postoperatively.
The use of vasopressors also allows the maintenance of adeuate perfusion pressures so as to allow for longer periods of hepatic retraction by the surgeon, and hence a potentially shorter operating time. Clear communication with the surgeon is important as sometimes it is necessary for the liver to be placed in its usual position for a period of time to overcome the hemodynamic consequences of liver retraction.
Prophylactic antibiotics used are cephalosporins and metronidazole. Gentamicin may also be required.
The Kasai is usually an open operation with a large subcostal incision, which usually takes between 2 and 4 hours. The laparoscopic approach is losing favor, as inadequate surgical exposure leads to poorer results. Robotic assisted laparoscopy has been used in an attempt to overcome this shortcoming; however, robotic surgery in babies is still an experimental technique. While surgeons adapt to robotic surgery, long operating time is a problem, prolonged CO2 pneumoperitoneum causes impaired ventilation, impaired venous return from the lower body with subsequent decreased cardiac output, lower body edema, and increased CO2 absorption requiring greater ventilation. The use of the robot also requires advanced planning so that rapid access to the patient is possible in an emergency, as the robot severely limits access to the patient during surgery.
A common intraoperative complication is hypotension, which can be treated with adequate filling volume and noradrenaline. Albumin 4% is often used as an intravenous volume expander to reduce free water infusion, which may lead to fluid overload post operatively; however, there are no data to support the use of colloid over crystalloid. Third space fluid losses can be significant and judicious fluid replacement is needed. Heat loss is managed by a warm operating theater, placing the baby on a convection blanket, and the surgeons irrigating with warm fluids. Small babies are at risk of hypoglycemia, so a 10% dextrose infusion is used on a separate line. Blood loss and coagulopathy are relatively rare problems; however, the anesthetist needs to anticipate these early so as not to get behind in red cell and clotting factor replacement. Last, air emboli can occur as the IVC and hepatic veins are elevated above the level of the atria during exteriorization.
a. Neurologic:
N/A
b. If the patient is intubated, are there any special criteria for extubation?
N/A
c. Postoperative management
Most patients are extubated and managed on the surgical ward after they are deemed stable in recovery. Red cells and clotting products are given as required. The peak coagulopathy is usually on postoperative day three. In the case of massive transfusion or other unanticipated complication, the patient is transferred to the intensive care unit intubated for warming and invasive pressure monitoring.
Third spacing can be significant. Fluid output is monitored and replaced with normal saline and 4% albumin in a 1:1 ratio. Serum electrolytes should be examined daily until the patient is off intravenous fluids and taking feeds.
Nasogastric drainage continues until bowel activity has resumed.
The hospital pain management service supervises an intravenous opioid infusion or an epidural infusion of local anesthetic.
Postoperative complications include ascending cholangitis, portal hypertension and varices, hepatic fibrosis, and hepatic failure.
What's the Evidence?
Benno, M. “Survival with the native liver after laparoscopic versus conventional Kasai portoenterostomy in infants with biliary atresia”. Ann Surg. 2011. pp. 253(The open Kasai gives superior results compared to the laparoscopic Kasai, probably due to reduced surgical exposure of the plate and anastomosis.)
Green, D, Howard, E, Davenport, M. “Anaesthesia, perioperative management and outcome of correction of extrahepatic biliary atresia in the infant: a review of 50 cases in the King's College Hospital series”. Paediatr Anaesth. vol. 10. 2000. pp. 581-9.
Mariano, E, Furukawa, L, Woo, R. “Anesthetic concerns for robotic-assisted laparoscopy in an infant”. Anesth Analg. vol. 99. 2004. pp. 1665-7.
Seefelder, C, Lillehei, C. “Epidural analgesia for patients undergoing hepatic portoenterostomy (Kasai procedure)”. Paediatr Anaesth. vol. 12. 2002. pp. 192-5.
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