Intraocular pressure after cardiopulmonary bypass surgery.

The ocular effects of cardiopulmonary bypass surgery were prospectively studied in 46 patients. We examined preoperative and post-operative visual acuity, intraocular pressure, body weight, fluids infused during surgery, hematocrit, and cardiopulmonary bypass time. On the first postoperative day mean intraocular pressure increased 2.1 mm Hg (P = .003) from baseline preoperative levels. Over the first postoperative day intraocular pressure increased in 29 (63%) of the patients. Three patients (7%) had a greater than 10 mm Hg rise. The mean intraocular pressure returned to baseline by the third postoperative day. Patient weight increased from preoperative levels an average of 9.3 lbs (P less than .0001) on day 1 and 6.5 lbs on day 3. Mean hematocrit decreased 11.3% (P less than .0001) on day 1 from baseline and remained at that level through day 3. None of the patients complained of visual dysfunction during the course of this study and none showed more than a two-line decrease in near visual acuity. The increase in intraocular pressure did not correlate with the postoperative weight gain or hemodilution. However, the medications necessary after cardiac surgery may be a significant confounding variable. This study demonstrates that one cause of ocular problems from cardiopulmonary bypass surgery may be related to the dynamics of intraocular pressure.