Abnormalities of pulmonary artery wedge pressures in sleep-induced apnea

Six patients with sleep apnea syndrome were studied with continuous hemodynamic monitoring during sleep. Sleep apnea had been previously documented with an average number of apneas per hour of sleep ranging from 23 to 93 ((mean 63). There was significant decrease in heart rate during sleep (82 +/- 5 to 69 +/- 6, P less than 0.01). There was a significant rise in systemic blood pressure (103 +/- 2 mn Hg to 116 +/- 6 mm Hg, P less than 0.05) and pulmonary artery pressure (20 +/- 1 mm Hg to 32 +/- 5 mm Hg) during sleep. In addition, pulmonary artery wedge pressure increased (12 +/- 2 mm Hg to 20 +/- 3 mm Hg, P less than 0.05) during sleep and 5 of the 6 patients developed an abnormal pulmonary wedge pressure. There was a significant decrease in PO2 during sleep (71 +/- 3 mm Hg to 49 +/- 2 mm Hg, P less than 0.005). These findings suggest that increases in pulmonary wedge pressures may be contributing to increase in pulmonary artery pressures in these patients during sleep.