A COMPARATIVE-STUDY OF THE EFFECTS OF ALMITRINE BISMESYLATE AND LATERAL POSITION DURING UNILATERAL BACTERIAL PNEUMONIA WITH SEVERE HYPOXEMIA

The management of patients with unilateral pneumonia and severe hypoxemia often represents a therapeutic challenge. Mechanical ventilation with the diseased lung uppermost may improve gas exchange, but it is not devoid of adverse effects. No hemodynamic measurements have been reported in patients ventilated in this manner; therefore, whether or not the improvement in Pa(O2) is counterbalanced by hemodynamic deterioration remains unknown. Almitrine bismesylate is a drug that seems able to improve gas exchange in patients with chronic obstructive pulmonary disease or the adult respiratory distress syndrome. The increase in Pa(O2) after its administration has been attributed to an improvement in ventilation perfusion relationships. Its use has never been reported during unilateral pneumonia with severe hypoxemia. We therefore compared its effects with those of lateral position in eight consecutive mechanically ventilated patients with unilateral pneumonia. Blood gas and hemodynamic measurements were performed both at maintenance Fl(O2) and at an Fl(O2) of 1.0. Almitrine (1 mg/kg over 1 h) had no effect on Pa(O2) under either Fl(O2) condition. Cardiac output remained unchanged, but mean pulmonary artery pressure increased from 22.5 +/- 1.2 to 26.5 +/- 1.3 mm Hg (p < 0.02). By contrast, lateral position had striking effects on Pa(O2), which increased from 100 +/- 14 mm Hg in supine position to 156 +/- 23 mm Hg (p < 0.01) when the abnormal lung was placed uppermost at maintenance Fl(O2) and from 207 +/- 21 (supine) to 300 +/- 28 mm Hg (lateral) (p < 0.01) at Fl(O2) 1.0. Arterial and mixed venous oxygen content were also increased (from 14.0 +/- 0.64 to 14.6 +/- 0.74 ml% [p < 0.01] and from 9.87 +/- 0.69 to 10.53 +/- 0.72 ml% [p < 0.05], respectively). No significant change in hemodynamic parameters was observed. In conclusion, almitrine had no beneficial effects on either gas exchange or hemodynamics, whereas lateral positioning markedly improved gas exchange without inducing any deleterious hemodynamic effects, thus potentially allowing a reduction in Fl(O2).