In a double-blind trial the effects of a single dose of doxapram (1–1.5 mg/kg) on the postoperative arterial oxygen tension of patients who had undergone surgical fixation of a fractured neck of femur was measured. In contrast to other reports of the effect of a single dose of doxapram, there was no improvement in arterial oxygen tension with respect to the control group. It is reasoned that doxapram may exert its effect by increasing the functional residual capacity in the immediate postoperative period. The central analeptic properties of doxapram may be grossly underestimated.
The widely held assumption that patients with a fractured neck of femur are significantly hypoxic pre-operatively is questioned.