A Randomised Controlled Trial on Haemodynamic and Intraocular Pressure Changes: A Comparison between Classic Laryngeal Mask Airway and Endotracheal Intubation UC01-UC04
Dr. Julie C R Misquith,
303, Embassy Court Apartments, New Balmatta Road, Mangalore-575001, Karnataka, India.
Introduction: Laryngeal Mask Airway (LMA) and endotracheal intubation are two methods of securing airway. Insertion of airway devices causes haemodynamic and Intraocular Pressure (IOP) changes. In the present study, authors compared the two devices and the changes they cause. The mechanism of IOP rise is secondary to increased sympathetic activity. In addition, adrenergic stimulation can also produce an acute increase in IOP, by increasing the resistance to the outflow of aqueous humour in trabecular meshwork between anterior chamber and Schlemn’s canal.
Aim: To compare the effects of LMA placement and endotracheal intubation on haemodynamics and IOP.
Materials and Methods: Sixty patients of American Statistical Association (ASA) Status 1 or 2 undergoing general anaesthesia were included in study. They were divided into two groups, Group 1 in which classic LMA was used and Group 2, in which endotracheal tube was used. All patients were given general anaesthesia following preoxygenation. Pre-airway manipulation haemodynamics and IOP were measured followed by measurement at one, two, three minutes post airway manipulation. The change in heart rate, systolic pressure, diastolic pressure, mean pressure and IOP was calculated by subtracting the actual values from those obtained post-induction. After the surgery, when the patient was fully awake trachea was extubated or LMA was removed whichever the case may be.
Results: The change in haemodynamic variables at one, two, three minutes in the intubation group was more and was statistically significant. The maximum change in haemodynamics occurred at one minute after airway manipulation. Though there was an increase in IOP in both groups, this was comparable and hence statistically not significant. The IOP in both the groups remained within the normal range even after airway manipulation.
Conclusion: In a patient who can tolerate the transient haemodynamic change an endotracheal intubation should not be a contraindication when minimal changes in IOP do not matter much.