Donald L. Rucknagel

Incentive Spirometry to Prevent Acute Pulmonary Complications in Sickle Cell Diseases

BACKGROUNDnThis study was designed to determine the incidence of thoracic bone infarction in patients with sickle cell diseases who were hospitalized with acute chest or back pain above the diaphragm and to test the hypothesis that incentive spirometry can decrease the incidence of atelectasis and pulmonary infiltrates.nnnMETHODSnWe conducted a prospective, randomized trial in 29 patients between 8 and 21 years of age with sickle cell diseases who had 38 episodes of acute chest or back pain above the diaphragm and were hospitalized. Each episode of pain was considered to be an independent event. At each hospitalization, patients with normal or unchanged chest radiographs on admission were randomly assigned to treatment with spirometry or to a control nonspirometry group. Each patient in the spirometry group took 10 maximal inspirations using an incentive spirometer every two hours between 8 a.m. and 10 p.m. and while awake during the night until the chest pain subsided. A second radiograph was obtained three or more days after admission, or sooner if clinically necessary, to determine the incidence of pulmonary complications. Bone scanning was performed no sooner than two days after hospital admission to determine the incidence of thoracic bone infarction.nnnRESULTSnThe incidence of thoracic bone infarction was 39.5 percent (15 of 38 hospitalizations). Pulmonary complications (atelectasis or infiltrates) developed during only 1 of 19 hospitalizations of patients assigned to the spirometry group, as compared with 8 of 19 hospitalizations of patients in the nonspirometry group (P = 0.019). Among patients with thoracic bone infarction, no pulmonary complications developed in those assigned to the spirometry group during a total of seven hospitalizations, whereas they developed during five of eight hospitalizations in the nonspirometry group (P = 0.025).nnnCONCLUSIONSnThoracic bone infarction is common in patients with sickle cell diseases who are hospitalized with acute chest pain. Incentive spirometry can prevent the pulmonary complications (atelectasis and infiltrates) associated with the acute chest syndrome in patients with sickle cell diseases who are hospitalized with chest or back pain above the diaphragm.

Time-dependent changes in the density and hemoglobin F content of biotin-labeled sickle cells.

Sickle red blood cells (RBC) are subject to a number of important cellular changes and selection pressures. In this study, we validated a biotin RBC label by comparison to the standard 51Cr label, and used it to study changes that occur in sickle cells as they age. Sickle RBC had a much shorter lifespan than normal RBC, but the two labels gave equivalent results for each cell type. A variable number of sickle, but not normal, RBC disappeared from the circulation during the first few hours after reinfusion. The number of biotinylated sickle reticulocytes was decreased by 50% after 24 h and 75% after 48 h, with a gradual decrease in the amount of reticulum per cell. The labeled sickle cells exhibited major density increases during the first 4-6 d after reinfusion, with smaller changes thereafter. A small population of very light, labeled sickle RBC was essentially constant in number after the first few days. Fetal hemoglobin (HbF) content was determined in isolated biotinylated sickle RBC after reinfusion, allowing an estimate of lifespan for RBC containing HbF (F cells) and non-F cells. The lifespan of sickle biotinylated RBC lacking HbF was estimated to be approximately 2 wk, whereas F cells survived 6-8 wk.

The Role of RIB Infarcts in the Acute Chest Syndrome of Sickle Cell Diseases

The acute chest syndrome is a generic term for pulmonary complications of sickle cell diseases with heterogeneous etiologies that include pneumonia, vaso-occlusion of pulmonary arterioles, rib infarction, and fat embolism syndrome. My review summarizes these etiologies, the evidence, and pathophysiology supporting the hypothesis that infarction of segments of ribs by the same vaso-occlusive process responsible for the acute episodes of pain (characteristic of the sickle cell diseases) is often involved in the acute chest structure. Inflammation associated with the infarct then causes splinting, hypoventilation, and hypoxia and further vaso-occlusion. The relationship with adult respiratory distress syndrome and fat embolism is also discussed. Use of the incentive spirometer combined with effective analgesia when chest pain is present is advocated for prevention of the pulmonary infiltrates. Newer understanding of the role of nitric oxide in regulating oxygen transport and its relationship to blood transfusions used in therapy of the acute chest syndrome are discussed.

Pre- and post-stroke MRI and neuropsychological studies in sickle cell disease: A case study

The case of a patient with sickle cell disease is presented in which neuropsychological and magnetic resonance imaging studies were completed prior to and after a right hemispheric stroke. The contribution of a new MR perfusion technique in understanding the neurological complications in this patient is discussed. This case illustrates the complex pathophysiology of neuropsychological deficits in SCD and underscores the need to develop models that better reflect this complexity.