Effects of atracurium on intraocular pressure, eye position, and blood pressure in eucapnic and hypocapnic isoflurane-anesthetized dogs.

OBJECTIVE

To determine effects of atracurium on intraocular pressure (IOP), eye position, and arterial blood pressure in eucapnic and hypocapnic dogs anesthetized with isoflurane.

ANIMALS

16 dogs.

PROCEDURE

Ventilation during anesthesia was controlled to maintain Paco2 at 38 to 44 mm Hg in group- I dogs (n = 8) and 26 to 32 mm Hg in group-II dogs (8). Baseline measurements for IOP, systolic, diastolic, and mean arterial blood pressure, central venous pressure (CVP), and heart rate (HR) were recorded. Responses to peroneal nerve stimulation were monitored by use of a force-displacement transducer. Atracurium (0.2 mg/kg) was administered i.v. and measurements were repeated at 1, 2, 3, and 5 minutes and at 5-minute intervals thereafter for 60 minutes.

RESULTS

Atracurium did not affect IOP, HR, or CVP Group II had higher CVP than group I, but IOP was not different. There was no immediate effect of atracurium on arterial blood pressure. Arterial blood pressure increased gradually over time in both groups. Thirty seconds after administration of atracurium, the eye rotated from a ventromedial position to a central position and remained centrally positioned until 100% recovery of a train-of-four twitch response. The time to 100% recovery was 53.1 +/- 5.3 minutes for group I and 46.3 +/- 9.2 minutes for group II.

CONCLUSIONS AND CLINICAL RELEVANCE

Atracurium did not affect IOP or arterial blood pressure in isoflurane-anesthetized dogs. Hyperventilation did not affect IOP or the duration of effect of atracurium.