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Positive end-expiratory pressure increases intraocular pressure in cats
U R Nimmagadda1, N J Joseph, M R Salem
1Department of Anesthesiology, Illinois Masonic Medical Center, Chicago 60657.
Critical Care Medicine
|June 1, 1991
Summary
Positive end-expiratory pressure (PEEP) significantly increased intraocular pressure in cats. This suggests higher PEEP levels may be detrimental for patients with elevated intraocular pressure.
Area of Science:
- Veterinary Anesthesia
- Ophthalmology
- Respiratory Physiology
Background:
- Positive end-expiratory pressure (PEEP) is used in mechanical ventilation.
- The effect of PEEP on intraocular pressure (IOP) is not fully understood.
- Understanding IOP changes during PEEP is crucial for patient management.
Purpose of the Study:
- To investigate the impact of varying PEEP levels on IOP in cats.
- To assess the relationship between PEEP, central venous pressure (CVP), and cerebrospinal fluid (CSF) pressure.
Main Methods:
- Anesthetized cats were mechanically ventilated at different PEEP levels (0, 5, 10, 15 cm H2O).
- Continuous measurements of IOP, heart rate (HR), mean arterial pressure (MAP), CVP, and CSF pressure were recorded.
- PEEP levels were applied in a random order.
Main Results:
- Intraocular pressure significantly increased at 10 cm H2O (20 mm Hg) and 15 cm H2O (21 mm Hg) PEEP compared to baseline (17 mm Hg).
- CVP and CSF pressure also increased significantly in parallel with IOP at all tested PEEP levels.
- No significant changes were observed in pHa, Paco2, HR, MAP, hematocrit, or temperature.
Conclusions:
- Elevated PEEP levels can lead to a significant increase in intraocular pressure in cats.
- These findings suggest that similar effects may occur in humans.
- Higher PEEP levels could be undesirable in patients with pre-existing ocular hypertension.