and hematologist. Potential sickle cell–related complications include acute chest syndrome, pain episodes, hyperhemolytic crisis, aplastic crisis, alloimmunization with delayed transfusion reactions, and infections. The outcome of children with SCD requiring a surgical procedure is improved by careful attention to the cardiorespiratory, hemodynamic, hydration, infectious, neurologic, and nutritional status of the child.93,98-100 If possible, procedures should be performed when the child is in his or her usual state of health with regard to the SCD. Attention should be directed toward chronic manifestations of disease because predictors of a poor postoperative outcome include increased age, recent exacerbations of the disease, and preexisting infection and pregnancy.101 Particular attention should be directed toward any recent history of acute chest syndrome, pneumonia, wheezing, and alloimmunization. Special efforts must be made to avoid perioperative hypoxia, hypothermia, acidosis, and dehydration because any of these events can result in serious morbidity. Many centers perform preoperative transfusions with the aim of reducing the complications of surgery and anesthesia.102 The largest study to examine the role of transfusion in the preoperative management of sickle cell anemia was a randomized study that compared exchange transfusion (with a goal of achieving an Hb value of > 10 g/dL and Hb S value of < 30%) versus simple transfusion (to achieve an Hb value of > 10 g/dL).94,102 This study concluded that not only was simple transfusion as effective as exchange transfusion in preventing perioperative complications but it also provided a significantly lower rate of transfusionrelated complications.94 The question of which procedures are safe to perform in children with SCD without preoperative transfusion remains controversial because there is a lack of randomized controlled trials to answer this question. However, simple transfusion to increase the Hb level to 10 g/dL for major procedures and blood replacement for both profound anemia of less than 5 g/dL and intraoperative hemorrhage appear appropriate. 103 Several studies suggest that minor procedures can possibly be safely undertaken without transfusion. 93,102,104 Alloimmunization can be minimized by giving antigen-matched blood (matched for K, C, E, S, Fy, and Jk antigens).100 Regardless of transfusion status, strong multidisciplinary collaboration is vital throughout the perioperative period. Intraoperative Management Anesthetic considerations are based more on the type of surgical procedure planned than on the presence of SCD because no single anesthetic technique has been shown to be the gold standard. However, regional anesthetic techniques may allow for opioid sparing in the postoperative period.101 The goals of anesthetic management are to avoid factors that predispose the patient to sickling (e.g., hypoxemia, hypothermia, dehydration, and acidosis). Careful monitoring for hypoxia, hypothermia, acidosis, and dehydration is essential. Monitoring should include arterial blood gases, digital oxygen saturation, end-tidal carbon dioxide, temperature, electrocardiogram, blood pressure, and urine output.101,105 Postoperative Management As with the preoperative and intraoperative periods, it is essential to prevent hypothermia, hypoxia, and hypotension throughout the postoperative period. Before extubation, the patient should be awake and oxygenating well. Once extubated, the patient must be carefully monitored with a digital oxygen saturation monitor and the pulmonary status critically assessed on a continuing basis. Continuous pulse oximetry should be provided in the early postoperative period. Assessment of fluid status should continue until the patient has resumed adequate oral intake and is able to maintain hydration without intravenous supplementation. All patients should receive incentive spirometry, as well as adequate hydration and oxygenation. Appropriate levels of analgesia (preferably by a continuous intravenous line and patient-controlled analgesia, if appropriate) should be provided so the patient is comfortable enough to cooperate with ambulation and maintain pulmonary toilet without oversedation. Experienced respiratory therapists should administer a vigorous program for pulmonary toilet. The patient must be monitored closely for the occurrence of pulmonary edema or atelectasis that can progress to acute chest syndrome.106 SPECIFIC SURGICAL CONDITIONS Adenotonsillectomy Adenotonsillectomy is a fairly common procedure in children with SCD. Adenotonsillary hypertrophy, which may be associated with early functional hyposplenism and obstructive sleep apnea secondary to enlarged adenoids, occurs somewhat frequently.93,107,108 As with other types of surgery, preoperative transfusions should be performed before surgery.109 Clinicians should be aware that postoperative complications may be greater if obstructive sleep apnea is present and that a younger age may influence the likelihood of postoperative complications.93,110 Cholelithiasis and Cholecystectomy Abdominal operations such as cholecystectomy and splenectomy are the most frequent type of surgery performed in patients with SCD.93,103 At present, no clear consensus exists regarding the appropriate therapy for SCD children who have cholelithiasis. The reported prevalence of cholelithiasis varies from 4% to 55%.111,112 This wide variation is dependent on the ages of the study population and the diagnostic modalities used.113 We routinely screen symptomatic children with ultrasonography and laboratory studies (e.g., total and direct bilirubin, serum glutamicoxaloacetic transaminase, serum glutamate-pyruvate
Posted on: Thu, 20 Mar 2014 04:26:42 +0000
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