CATARACT SURGERY;

EFFECTS OF SPONTANEOUS VERSUS CONTROLLED VENTILATION ON INTRAOCULAR PRESSURE DURING GENERAL ANAESTHESIA

Abstract

Objective: To compare the effects of spontaneous versus controlled ventilation on Intraocular
Pressure (IOP) with concomitant haemodynamic changes during cataract extraction and intraocular (IOL) implant
surgery under anaesthesia. Design: Comparative study. Place and Duration of Study: The study was conducted at
department of Anesthesiology Combined Military Hospital Jhelum Cantt from Jan 2005 to Oct 2005. Subjects and
Methods: 40 ASA I and II patients of both sexes aged 40-68 years, undergoing surgical cataract extraction were
studies. In 20 patients ventilation was controlled while the other 20 patients breathed spontaneously during surgery.
IOP was measured preoperatively in non-operated eye.Results: Intraocular pressure (IOP) decreased below the base
line after induction of anaesthesia but it markedly increased after intubation in both group. During operation IOP
decreased more in controlled ventilation group than spontaneous ventilation group. At the end of surgery before
extubation, IOP increased in both groups with a greater rise in spontaneous ventilation group and extubation was
followed by a further rise in IOP in both groups. Heart rate (HR) and arterial blood pressure (BP) changes followed
almost the same pattern as IOP. Conclusion: General anaesthetics decrease IOP in general. Laryngoscopy and
intubation are anaesthesia-related events, which cause rise in IOP. In appropriate patients, general anaesthesia with
controlled ventilation is an acceptable technique for intraocular surgery offering advantages in terms of intraocular
pressure and cardiovascular stability compared to spontaneous ventilation.