PURPOSE: Acute chest syndrome in Sickle Cell Disease (SCD)is associated with pulmonary hypertension. Red cell/exchange transfusion may reduce pulmonary pressures. We sought to determine the hemodynamic changes which occur during treatment of acute respiratory failure in SCD patients.
METHODS: Pulmonary hemodynamics and other laboratory data were reviewed in 12 adult SCD patients admitted to the medical intensive care unit (ICU) and who had varying degrees of respiratory insufficiency. Pulmonary hemodynamics were obtained by Swan-Ganz catheterization at baseline (when catheter was first inserted) and one and two days thereafter. Management was supportive and also directed at the underlying condition. All but one patient, who had multiple RBC alloantibodies, were transfused and/or exchange transfused.
RESULTS: Their mean age was 36 years (range 18 –56 y), 8 of them (67%) were male, and all but one (92%) had the Hb SS genotype. Their mean Po2/fio2 ratio was 253 ± 85 SD (range 123 –400). Their ICU admission diagnoses included acute chest syndrome/pneumonia, sepsis, metabolic acidosis, and pulmonary hypertension. The table shows that the Po2/fio2 ratios remained unchanged for 2 days even though most patients eventually recovered. Hemodynamic improvement was suggested by a lowering of the pulmonary pressures and central venous pressure (CVP), but these differences were statistically significant only for the pulmonary arterial systolic (PAs) and CVP values. Three patients died while in ICU (25%), the remaining patients improved and were discharged from the hospital.
CONCLUSION: Lowering of pulmonary pressures (including wedge pressures) and CVP occurred in association with transfusion-related hematocrit increases. This is consistent also with the improved vascular flow that is expected when the proportion of sickling RBCs in circulation is reduced by the transfused RBCs.
CLINICAL IMPLICATIONS: Hemodynamic monitoring during the acute chest syndrome, not previously described, shows that a fall in CVP followed by a reduction in pulmonary arterial systolic pressure occur early in treatment. A larger cohort may help to determine whether these parameters are markers of outcome in acute respiratory insufficiency in the sickle cell patient.
DISCLOSURE: Reverly John, None.