ANEMIA INCREASES WORK OF BREATHING IN CHR ONIC LUNG-DISEASE

Background: Pulmonary diseases with marked disorders in gas exchange o r chronic overload of the respiratory pump needs increased ventilatory requirements. Additionally in these patients anemia may aggravate the ventilatory load. We thereby evaluated whether in these patients trea tment of anemia (red blood cell transfusion: RBCT) leads to an improve ment of the ventilatory load in comparison to the anemic patients with out pulmonary disease. Patients and Methods: We examined 21 patients w ith an anemia (Hb < 11 g%, 12 men). Fifteen patients had a pulmonary d isease (group A), 6 patients suffered from anemia without pulmonary di sease (group B). Subsequently within 8 hours the patients got 2 to 3 R BCT. We studied the patients on the day of admission and 24 to 36 hour s after transfusion. The patients kept bed rest for spontaneous breath ing 1 hour prior to the actual examination without supplemental oxygen . Hemoglobin, hematocrit, respiratory rate, respiratory minute volume and arterial blood gases were measured. On the following day we repeat ed the same procedures. Results and Conclusions: Anemia in patients wi th an increased ventilatory requirement causes an additional increase of work of breathing. In these patients - in contrast to patients with out compromised lungs - 2.2 red blood cell transfusions lead to an imp ressive reduction of VE labour 20%) and correspondingly also to a redu ction of WOB.