Page 1305 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

912 PART 7: Hematologic and Oncologic Disorders

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The volume of blood acutely sequestered from the circulation can cause PERIOPERATIVE MANAGEMENT
severe anemia and life-threatening hypotension. Because most patients Patients with sickle cell disease have a high risk of perioperative
with sickle cell anemia have splenic atrophy by age 10 years due to complications, with 10% to 50% developing a VOC or ACS postop-
gradual microinfarction, splenic sequestration occurs only in those eratively. Careful preoperative anesthesiology consultation should be
patients with significant residual splenic parenchyma, namely young undertaken. Many sickle cell centers have traditionally performed serial
children with sickle cell anemia and individuals at all ages with less transfusion or exchange transfusion preoperatively with a goal of prevent-
severe sickling syndromes, such as hemoglobin SC disease and hemo- ing postoperative complications by reducing the hemoglobin S fraction
globin S-β -thalassemia. Splenic sequestration when acute and severe to less than 30%, with a final total hemoglobin level of at least 10 g/dL.
+
should be treated with rapid red cell transfusion, analogous to the treat- A randomized study by Vichinsky et al showed that preoperative simple
ment of acute severe traumatic blood loss. Overtransfusion should be transfusion with a goal of raising the total hemoglobin concentration to
avoided because, during resolution, sequestered red cells can be abruptly 10 g/dL, without a specific goal for hemoglobin S percentage, has similar
released, potentially causing hyperviscosity. When splenic sequestration efficacy. However, this study included predominantly patients with less
syndrome occurs in adolescents or adults with hemoglobin SC disease, invasive surgical procedures, such as tympanostomy tube placement
it may be associated with acute splenic infarction. This clinically impres- or laparoscopic cholecystectomy. Some centers still prefer to perform
sive syndrome can present with very high-grade fever, extraordinary exchange transfusion before major surgery in patients with sickle cell
splenic pain and tenderness, and enormous splenomegaly. Sonography disease, although many transfuse less aggressively. A careful risk-benefit
or computed tomography may depict inhomogeneity representative of evaluation must be applied to each case, especially in patients with a
hemorrhagic infarction, which should be differentiated from possible history of red blood cell alloimmunization.
splenic abscess. Patients with acute splenic infarction can be managed Supportive care should include careful attention to avoiding dehydra-
medically with transfusions and supportive care. 45 tion, overhydration, deoxygenation, vascular stasis, low temperature,
Recurrence of splenic sequestration or infarction indicates a risk of acidosis or infection. The operating room should be kept warm, and
multiple future recurrences, and some have recommended splenec- warming devices should be used for the patient. Oxygenation status
tomy. If this is done, it should probably be done electively after medical should be closely monitored intraoperatively and postoperatively, and
management and clinical resolution of the acute episode to minimize incentive spirometry should be prescribed postoperatively. The literature
operative risk. regarding perioperative management of patients with sickle cell disease
■ PRIAPISM has been reviewed in more detail by Marchant and Walker. 49

Priapism refers to pathologically prolonged erection of the penis, which TREATMENTS
46
is often extremely painful. Although its pathophysiologic mechanism
remains to be elucidated, it seems likely that penile venous outflow ■ OXYGEN AND FLUIDS
is obstructed by sickled erythrocytes, compounded by disordered
vasomotor function in penile blood vessels. Case reports of many Because hypoxemia and dehydration can trigger sickling, it is important
therapeutic approaches have been proposed based on experience in to prevent these from developing. Contrary to traditional teaching in
limited numbers of patients, but these have rarely proved to be of many medical training programs, there is no indication of benefit from
benefit in larger clinical experiences. The most widely recommended aggressive hydration in patients who are not dehydrated or from oxygen
acute treatment for severe episodes is exchange transfusion, although therapy in the absence of hypoxemia. Excessive fluid resuscitation may
evidence of its efficacy is limited. Therapies of questionable value have even compromise some older patients who have some degree of conges-
included adrenergic agonists, nitrates, and a surgical approach known tive heart failure or renal insufficiency.
relatively large single-institution study involving percutaneous drain- ■ ANALGESICS
as a Winter shunt. Only one therapy has shown some benefit in a
age and irrigation of the corpus cavernosum initiated within 3 hours At times, acetaminophen can suffice for mild pain. More severe pain
of onset. Although the grade of evidence remains only moderate, the often requires addition of an oral opioid analgesic such as codeine,
47
urology community has recognized the importance of promoting early hydromorphone, morphine, or oxycodone; morphine and oxycodone are
penile aspiration in cases of severe acute priapism. One very interesting, available as short-acting or sustained-release preparations (Table 96-9).
counterintuitive approach has been reported. Sildenafil, normally used Severe pain episodes are best treated with intravenous opioids, usually
clinically to treat erectile dysfunction, given in single 50-mg doses as morphine or hydromorphone, with considerable added convenience to
needed, rapidly relieved several episodes of priapism in three patients patient and clinician when administered via a patient-controlled analge-
with sickle cell disease. Because of the possibility that this drug might sia pump (Table 96-10). Patients with severe pain may also benefit from
48
also be capable of inducing priapism, its use cannot be recommended the parenteral nonsteroidal anti-inflammatory drug ketorolac, although
until further research is conducted. questions have been raised about potential impairment of renal blood

TABLE 96-9 Parenteral Analgesics Commonly Used in Painful Crisis of Sickle Cell Disease a
Class Agent Adult Dose Pediatric Dose Notes
NSAID Ketorolac 30 mg IV q 6 h 0.5 mg/kg IV q 6 h After 3 days, change to oral ibuprofen due to risk of gastrointestinal bleeding;
omit in patients with known pulmonary hypertension; risk of kidney dysfunction
Opioid Morphine 5-20 mg IV q 3 h 0.1-0.2 mg/kg IV q 3-6 h Usually use morphine as opioid except in cases of previous morphine
intolerance
Hydromorphone 1-4 mg IV q 3-6 h 0.015-0.03 mg/kg IV q 3-6 h
a Most patients will require midrange doses. Use a lower dose range in elderly or debilitated patients or consider an upper dose range in opioid-tolerant patients. Highly tolerant patients at times may require even
larger doses than the ranges listed. The use of meperidine is generally discouraged, due to seizures occasionally seen as a complication of its use. Most patients can obtain satisfactory analgesia with morphine or
hydromorphone. Opioid-induced side effects often require medical management (see text).
IV, intravenously; NSAID, nonsteroidal anti-inflammatory drug.

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