INTRAOCULAR-PRESSURE DURING MECHANICAL VENTILATION WITH DIFFERENT LEVELS OF POSITIVE END-EXPIRATORY PRESSURE

Objective: To determine the effect of positive end-expiratory pressure (PEEP) on intraocular pressure. Design: Prospective, controlled, long itudinal, dual center study. In one group, patients served as their ow n control. In the second group, isolated determinations of intraocular pressure were made in mechanically ventilated patients receiving PEEP . Setting: Adult intensive care units of two university hospitals. Pat ients: Intraocular pressures were measured serially in eight patients during the recovery phase of different clinical conditions and in 22 p atients receiving mechanical ventilation with PEEP greater-than-or-equ al-to 10 cm H2O for >24 hrs. Interventions: Group A) In eight patients , a PEEP dose-response curve was established (PEEP 0,5,10,15, and 0 cm H2O every 15 mins). Intraocular pressures were measured at the end of each period. Group B) In 22 patients, measurement of intraocular pres sures were done while the patients received mechanical ventilation wit h PEEP greater-than-or-equal-to 10 cm H2O for at least >24 hrs. Measur ements and Main Results: In both groups, there was a positive correlat ion between the PEEP level and the central venous pressure (p < .05 in group A, and p < .03 in group B). No relationships between intraocula r pressure and PEEP or central venous pressure were observed. However, there was a correlation between intraocular pressure and length of PE EP therapy (p < .03). We found ocular hypertension in only one patient (right eye intraocular pressure = 26 mm Hg; left eye intraocular pres sure = 24 mm Hg). Conclusions: Short-term therapy with PEEP of less-th an-or-equal-to 15 cm H2O does not present a clinically important signi ficant risk for intraocular pressure increase in a population with nor mal basal ocular tonometry. During prolonged mechanical ventilation wi th PEEP, increments in intraocular pressure may occur, but these incre ments appear to not be of a clinically relevant magnitude.