Changes in intraocular pressure during cardiopulmonary bypass.

PURPOSE: The aim of the present study was to investigate the changes in intraocular pressures (IOP) in patients who underwent pulsatile and non-pulsatile cardiopulmonary bypass (CPB).

METHODS: A total of 42 patients operated for elective coronary bypass surgery (CABG) on CPB were randomly allocated to pulsatile (Group P) and non-pulsatile (Group N) groups. Pulsatile flow was applied to Group P patients during crops-clamp period. The IOP measurements were made before and after the induction of anesthesia, before the onset of CPB, on the 5th, 15th, 30th, 45th, and 60th min of CPB, after CPB and at the end of the operation. The results of repetitive measurements were analyzed at different intervals and in two groups.

RESULTS: The second IOP measurements of right and left eyes displayed statistically significant decreases from the baseline level [11.9 ± 2.9 (p = 0.0001) and 12.5 ± 3.2 (p = 0.0001), respectively]. The significant decrease in the IOP values persisted in the repeated measurements except for the 5th min of CPB values [17.0 ± 3.5 (p = 0.346) and 16.7 ± 3.6 (p = 0.399)]. Comparison of two groups demonstrated significant differences at pre-CPB (right 12.8 ± 2.3 vs. 10.8 ± 2.4; p = 0.013 and left 13.3 ± 2.4 vs. 11.5 ± 2.5; p = 0.023), and 5th min of CPB measurements (right 18.5 ± 3.1 vs. 15.9 ± 3.4; p = 0.015; left 18.2 ± 3.0 vs. 15.7 ± 3.6; p = 0.019).

CONCLUSION: We noted a steady decrease in repeated IOP measurements except for the transient increase in CPB values on 5th min. The IOP values were higher in pulsatile CPB group in pre-CPB and 5th min of CPB measurements; however, the difference was not significant in the repeated measurements.