Dopamine and intraocular pressure in critically ill patients

Background: A recently released dopamine-1 receptor agonist, fenoldopam, increases intraocular pressure (IOP) in both healthy volunteers and patients with chronic ocular hypertension. Dopamine, a potent agonist at both dopamine-1 and -2 receptors, is frequently infused in critically ill patients for its inotropic, renal vasodilatory, and natriuretic effects. The authors hypothesized that low doses of dopamine would significantly increase IOP. Methods: Patients in the intensive care unit who were currently receiving dopamine infusions of less than 5 μg · kg^-1 · min^-1 were studied. After local ocular anesthesia was obtained, baseline IOP was measured in each eye with a hand-held tonometer. IOP was then determined after dopamine was discontinued. Results: Twenty-three patients received a mean dopamine infusion of 2.6 ± 0.2 μg · kg^-1 · min^-1. Twelve of the 23 patients were receiving mechanical ventilation during the study. Mean IOPs in nonventilated patients (n = 11) off dopamine were 13.1 ± 0.9 mmHg (left eye) and 12.6 ± 0.9 mmHg (right eye). Mean IOPs for the same patients receiving dopamine were significantly higher at 16.1 ± 0.9 mmHg (left eye) and 15.9 ± 1.1 mmHg (right eye). Mean IOPs in intubated patients (n = 12) off dopamine were 12.3 ± 0.7 mmHg (left eye) and 12.5 ± 1.2 mmHg (right eye). Mean IOPs for the same patients while receiving dopamine were significantly higher in intubated patients at 17.8 ± 1.3 mmHg (left eye) and 17.3 ± 1.3 mmHg (right eye). The average mean elevation in IOP in patients while receiving dopamine was significantly higher in intubated patients as compared with nonintubated patients (5.2 ± 0.9 mmHg vs. 3.1 ± 0.6 mmHg). Conclusions: Commonly used doses of dopamine are associated with increased IOP in critically ill patients. Although normal patients should be able to tolerate this elevation safely for several weeks, there may be a potential risk in patients with preexisting glaucomatous nerve damage or ocular hypertension, especially if they are sedated and mechanically ventilated.