To Compare Effect of Sevoflurane Versus Desflurane on the Return of Swallowing Reflexes in the Elderly

This is a prospective, double-blind, randomized controlled trial by single operator. American Society of Anaesthesiologists' classification of physical status I-II male and female patients aged 60-85 year scheduled to have general anesthesia for surgical procedures were recruited. Patients recruited will be given 20mls of water to swallow in the upright position prior to surgery after obtaining informed consent. All patients enrolled are judged to have adequate swallowing if no coughing or drooling occurred after the water passed into the mouth, and no water remained in the oropharynx upon subsequent visual inspection.

The anaesthetist in charge of the patients enrolled in the study will be given a sealed envelope containing the name of the randomised gas to be used for the patient. At the end of surgery, an observer who is blinded to the anaesthethic allocation will record the relevant data. The blinded observer determined the time to first appropriate response to command (asking the patient to 'open his/her eyes' or squeezing the observer's hand, state his/her name or state date of birth) every 30s after discontinuation of anesthetic administration and removal of LMA. Exactly 5 minutes after appropriate verbal response, patient was asked to swallow 20mls of water in a 30 degree upright position. Successful swallowing is defined as ingestion of the 20mls of water without coughing or drooling. If swallowing was successful, the study was concluded. If it was unsuccessful, the patient was asked to swallow at 5, 10, 15, 20, 25 and 30 minutes, with termination of participation after successful swallowing. A stopwatch will be used to time the duration to recovery.

A study sample size of 60 is selected, with a power of 0.80 taken as the standard of adequacy. A p-value of < 0.05 is taken as the criteria for the test result to be statistically significant and data will be analyzed.