Response of cerebrospinal fluid pressure to continuous positive airway pressure in volunteers

The effect of a 10-min period of continuous positive airway pressure (CPAP) of 12 cm H2O on lumbar cerebrospinal fluid pressure (CSFP), cerebral perfusion pressure (CPP), central venous pressure (CVP), mean arterial pressure (MAP), heart rate (HR), and end-tidal carbon dioxide (ETCO2) was studied in eight volunteers. CSFP increased (7 +/- 4 control vs 11 +/- 4 mm Hg; P < 0.001; mean +/- SD) and CVP increased (2 +/- 2 control vs 5 +/- 3 mm Hg; P < 0.001; mean +/- SD) when CPAP of 12 cm H2O was applied. CPP decreased slightly during CPAP (79 +/- 13 vs 74 +/- 19 mm Hg; P < 0.05; mean +/- SD), whereas MAP, HR, and ETCO2 remained unchanged. The findings of our study suggest that changes in CSFP and CPP due to moderate levels of CPAP, although statistically significant, are probably of only minor clinical importance.