A Clinical Study of Intraocular Pressure Changes With Vecuronium Bromide and Pancuronium Bromide

Abstract

BACKGROUND: The maintenance of intraocular pressure forms the mainstay of anesthetic management of intraocular surgery. It is desirable to achieve a normal or reduced intraocular pressure before the eye is opened to avoid expulsive hemorrhage and ocular disruption at the time of incision. Therefore the ideal anesthetic technique for intraocular surgery should produce a moderate reduction in intraocular pressure, or maintain intraocular pressure at near normal values and avoid marked fluctuations during surgery (George et al, 1979). The use of suxamethonium is associated with significant rise in intraocular pressure with a peak increase between 2 and 4 minutes following administration and return to base line value after 6 minutes. The outcome of eye surgery, particularly when there is globe injury depends to a large extent on good control of intraocular pressure not only during maintenance, but also at induction of anesthesia. This is usually achieved by use of non-depolarizing muscle relaxant. Pancuronium when used in relatively larger doses is known to have a faster onset of action and also the block may be prolonged. Vecuronium is intermediate acting and free of cardiovascular and other side effects even when used in larger doses. AIMS AND OBJECTIVES: To study the effect of vecuronium bromide an intermediate acting nondepolarising muscle relaxant on intraocular pressure compared with pancuronium bromide, a long acting nondepolarising muscle relaxant. MATERIALS AND METHODS: Study Design: Comparative randomized study. Sample Size: 60 adult patients between 16-60 years subjected for elective nonophthalmological surgical procedure. Sampling Method: Randomized double blind study. Study groups: Group I: 30 patients received pancuronium bromide 0.08 mg/Kg of body weight. Group II: 30 patients received vecuronium bromide 0.1 mg/Kg of body weight. RESULTS: The total number of patients studied is 60. 30 patients in Group I and 30 patients in Group II. I.O.P Changes: Fall of intraocular pressure in all 30 patients is seen in Group 2. Pulse rate changes: The mean resting pulse rate was 81±6.7 in Group I and 81±6 in Group II. After administration of pancuronium pulse rate was 22.22% more than resting value but after administration of vecuronium there was no change in pulse rate. The pulse rate gradually came down but remained 8.64% more than resting value 10 minutes following intubation in Group I when as it remained 2.47% more than the resting value in Group II. Systolic Blood Pressure Changes: In Group I the mean systolic blood pressure fell by 1.66% and in group II by 1.65% below the resting value. Diastolic Blood Pressure Changes: In Group I on induction with thiopentone, the mean diastolic blood pressure fell by 1.23% below the resting value and in group II by 1.65% below the resting value. CONCLUSION: Hence it is further concluded that pancuronium bromide is the relaxant of choice in patients for ocular surgery where there is need for prolonged anesthesia or when hypotension is undesirable and vecuronium bromide is go...