Effects of induced relative hypoxia during the postoperative period of abdominal oncologic surgery, on hemoglobin and reticulocyte levels: a prospective, randomized controlled clinical trial
© Khalife et al.; licensee BioMed Central Ltd. 2012
Published: 20 March 2012
Anemia is a frequent complication in oncologic patients. Erythropoietin (EPO) stimulating agents are known as alternatives to transfusion. However, they expose patients to thrombosis and are expensive. Recently, a new phenomenon, the normobaric oxygen paradox (NOP), has been described. In brief, transient hyperoxia followed by a prolonged return to normoxia acts as an effective trigger for EPO production. The mechanism depends on free oxygen radicals and on reduced glutathione (GSH) availabilities. Also, N-acetylcystein (NAC) is known to regenerate the stock of GSH. Very few clinical trials have investigated this phenomenon . The goal of this study was to test the NOP theory on the evolution of hemoglobin and reticulocytes in patients receiving intermittent oxygen with or without NAC compared to a control group.
This prospective, randomized study included 78 patients (three groups). The first group (G1; n = 26) received 60% FiO2 for 2 consecutive hours on the first, third, and fifth days postoperatively. The second group (G2; n = 26) in addition to oxygen received NAC 200 mg/day for 5 days. The third group (G3; n = 26) was the control group which did not receive any oxygen variation. On postoperative day 6, hemoglobin, hematocrit and reticulocytes were measured and compared to the baseline values. A total of five patients (three in G1 and two in G2) were excluded for discontinuing oxygen and/or early discharge from hospital.
Induced relative hypoxia seems to be an effective stimulus for reticulocyte synthesis. However, further investigations are needed to confirm these findings and their impact on hemoglobin.
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