Page 1306 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 96: Sickle Cell Disease 913

transfusion. As such, the intensivist must be well versed in the indications,
TABLE 96-10 Approaches for Patient-Controlled Analgesia a
complications, and pitfalls of transfusion therapy in this population.
Adult Dose Pediatric Dose Patients with sickle cell disease have severe chronic anemia, and they
Agent Continuous Demand Continuous Demand generally tolerate transient episodes of at least a 20% decrease in their
baseline hemoglobin level quite well, if the reticulocyte count remains
Morphine 1-2 mg/h 1-2 mg 0.01-0.03 mg/kg 0.01-0.03 mg/kg high. Knowledge of a given patient’s baseline parameters can help to
per hour
determine the need for transfusion for exacerbation of anemia. The
Hydromorphone 0.2-1 mg/h 0.2-1 mg 0.003-0.005 mg/kg 0.003-0.005 mg/kg most severe and life-threatening anemia and reticulocytopenia occurs
per hour during aplastic crisis resulting from infection with the parvovirus B19,
a In adults and children, common parameters include 6- to 10-minute lockout, limited to five demand otherwise known as erythema infectiosum, fifth disease, or slapped-
doses per hour. Meperidine should never be administered by continuous infusion. Most patients will cheek disease. Life-threatening anemia and hypovolemia due to splenic
require midrange doses. Use a lower dose range in elderly or debilitated patients or consider an upper sequestration are other such indications, discussed in more detail below.
dose range in highly opioid-tolerant patients. Highly tolerant patients at times may require even larger There are several important transfusion issues unique to patients
doses than the ranges listed. Opioid-induced side effects often require medical management (see text). with sickle cell disease to consider. First, transfused red cells should be
negative by Sickledex or another rapid screening test to exclude blood
flow. Ketorolac also presents a risk of gastrointestinal hemorrhage, from sickle trait donors. Second, the detailed red cell phenotype should
particularly if used for 5 days or longer. We recommend that nonste- be ascertained in the blood bank, particularly for patients who will be
roidal anti-inflammatory agents be withheld in patients with sickle cell chronically transfused, such as children with a new stroke. This permits
disease with pulmonary hypertension or serum creatinine level above more directed management of alloimmunization to red cell antigens,
0.8 mg/dL. Clinicians should consider the baseline narcotics the patient although the actual approach is controversial. The rate of alloimmuniza-
is using for determining an adequate dose of narcotics. Opioid toler- tion to red cell antigens in patients with sickle cell disease is 18% to 36%,
ance due to previous chronic or frequent opioid administration may be most often involving the D, C, and E antigens in the Rh system and less
an indication for much larger doses of opioids for acute pain control. often the Kell, Kidd, and Duffy blood groups. This is attributable in large
Elderly or debilitated patients may require smaller doses of opioids to part to discrepancy in allele frequency between these patients of African
reduce toxicity. Opioid therapy may result in constipation, nausea, or descent and the blood pool from donors of mostly European descent.
pruritus. A laxative such as Senokot should be administered prophy- One workshop report has recommended the use of red cell units pro-
lactically. Nausea may be treated with diphenhydramine, hydroxyzine, phylactically matched to prevent sensitization to the Rh antigens D,
51
promethazine, ondansetron, or dolasetron. Pruritus may be treated with C, and E and the Kell antigen K. However, others have advocated
diphenhydramine or hydroxyzine. Very severe pruritus may respond to matching these antigens only after the patient has become immunized
52
naloxone 0.25 µg/kg per hour as a continuous intravenous infusion. This to antigens. The high rate of alloimmunization in patients with sickle
small dose can block opioid receptors associated with pruritus without cell disease promotes a higher incidence (3%) of delayed hemolytic
blocking those associated with analgesia. Detailed recommendations for transfusion reactions. These are defined as premature clearance of trans-
analgesia in patients with sickle cell disease have been published. 50 fused red cells, usually several days after transfusion. In some cases, the
hemoglobin level may decrease to below the pretransfusion level, with
■ INCENTIVE SPIROMETRY the immune reaction to transfused cells apparently generalizing to also
Bedrest during a pain crisis may lead to pulmonary atelectasis. This can involve the patient’s own red cells, a phenomenon that has been called
“bystander hemolysis.”
trigger ACS (see below). Bedside incentive spirometry during pain crisis Because of this complication, it is critical to obtain a transfusion
has been shown to prevent the development of pulmonary infiltrates. antibody history from blood banks where a patient was previously trans-
■ TRANSFUSION fused. Over several months, alloantibody titers to red blood cell antigens
may become undetectable on a routine type and cross-match but remain
Although there is probably no indication for treatment of the acute pain capable of mediating a transfusion reaction. The resulting delayed trans-
crisis, most other acute serious complications of sickle cell disease can fusion reaction in an acutely ill hospitalized patient can be catastrophic,
be stabilized through the use of transfusions to diminish the percentage with hemoglobin levels decreasing to 2 to 3 g/dL.
of circulating hemoglobin S. Table 96-11 lists indications for transfusion Simple transfusion is sufficient for correcting severe anemia, but
therapy. It is clear from reviewing this list that almost any sickle cell anemia exchange transfusion can more rapidly dilute sickle hemoglobin to less
patient who requires an ICU visit is likely to require a simple or exchange than 40% of circulating hemoglobin, which is desirable in acute life-
threatening sickle cell complications, in particular stroke, ACS, and mul-
tiorgan failure syndrome. Exchange transfusion may be accomplished
TABLE 96-11 Acute Indications for Transfusion in Patients With Sickle Cell Disease rapidly and isovolumetrically by erythrocytapheresis, when this pro-
Indication Transfusion Form cedure is available (Table 96-12). This requires upper extremity veins
sufficient for two large-bore needles, placement of a Quinton or similar
Severe anemia associated with high output cardiac failure, dyspnea, Simple apheresis, or hemodialysis venous catheter in a central vein (femoral,
postural hypotension, angina, or cerebral dysfunction internal jugular, or subclavian). Alternatively, manual exchange transfu-
Sudden reduction in hemoglobin concentration (splenic or hepatic Simple sion may be performed by using one of several protocols, with a goal of
sequestration, aplastic crisis) replacing 70% of the sickle red cell mass with transfused red cells. One
Acute or suspected stroke Exchange simplified approach for adults is presented in Table 96-12. Another
approach useful in children and adults is to exchange the red cell mass
Multiorgan failure syndrome Exchange twice, as calculated below:
Acute chest syndrome with severe hypoxia Exchange
2 × (patient hematocrit, decimal, not %)
Acute chest syndrome with acute anemia Simple × (patient weight in kg) × (70 mL/kg)
Preoperative preparation, hemoglobin SS Simple volume transfused = average hematocrit of transfused
Preoperative preparation, hemoglobin SC, major surgery Partial exchange packed red bloodcells, usually 0.55
Acute severe priapism Exchange This volume may be transfused while whole blood is being withdrawn
SC, hemoglobin sickle cell disease; SS, homozygous sickle cell disease. from a high-flow site, often an arterial or central venous line. The

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