INTRA OCULAR PRESSURE

EFFECTS OF LARYNGEAL MASK AIRWAY AND TRACHEAL INTUBATION DURING CATARACT SURGERY UNDER GENERAL ANAESTHESIA

Abstract

Objective: To compare the effects of Laryngeal Mask Airway (LMA) and tracheal
intubation on Intra Ocular Pressure (IOP) with concomitant haemodynamic changes during cataract extraction
and intra ocular lens (IOL) implant surgery under general anaesthesia. Design: Comparative study. Place and
Duration of Study: The study was conducted at department of Anaesthesiology Combined Military Hospital
Jhelum from April 2003 to December 2003. Subjects and Methods: 40 ASA I and II patients of both sexes
aged 40-68 years, undergoing surgical cataract extraction were studied. 20 patients were intubated endotrachealy
while LMA was inserted in other 20 patients. Ventilation was controlled in both groups. IOP was measured
preoperatively in non-operated eye. Results: Intra ocular pressure (IOP) decreased below the base line after
induction of anaesthesia but it markedly increased after intubation in tracheal tube (TT) group whilst there was
less increase in LMA group. During operation IOP decreased to near pre-induction value in both groups. At
the end of surgery, before extubation . IOP increased significantly in TT group with a small rise in LMA group
and extubation was followed by a further rise in IOP in TT group. while removal of LMA was not accompanied
by increase in IOP. Heart rate (HR) and arterial blood pressure (BP) changes followed the same pattern as IOP.
Conclusion: General anaesthetics decrease IOP in general. Laryngoscopy and intubation are anaesthesiarelated
events, which cause rise in IOP. In appropriate patients LMA is an acceptable technique for intra ocular
surgery offering advantages in terms of intra ocular pressure and cardiovascular stability compared to tracheal
intubation.