PREOPERATIVE FASTING IN GENERAL ANAESTHESIA
Patients have historically being starved of solids and fluids for a period of time prior to having surgery under general anaesthesia .The main aim of preoperative fasting is to reduce the event sequence which could begin with regurgitation, aspiration followed by pulmonary damage, pneumonitis and /or death the incidence of which is low .The aspiration of the gastric contents may occur during induction of anaesthesia when the laryngeal and pharyngeal reflexes are diminished. (Brady et al 2010) Mendelson first described 66 cases of aspiration between 1932 and 1945 which lead to research into the causes and consequences of pulmonary aspiration. (Mendelson 1946)
Current preoperative fasting guidelines requires the patients to starve for 6 hours after solid food and 2 hours after clear fluids before induction of anaesthesia (ASA 1999) children should be starved for 6 hours after solid food and / or formula /cows milk, 4 hours after breast milk and 2 hours after clear fluids .Clear fluids is one through which newsprint can be read. Gastric emptying is impaired by trauma, labour and opoid analgesics. The 2 hour fasting period for fluids neither increases the residual gastric volume nor decreases the pH, which is determined by oral intake, gastric secretion and gastric emptying (Levy 2006) Levy goes further to stress that many comparisons of fasting intervals have proved that fasting intervals have proved that residual gastric volume is if anything decreased by shorter fasting intervals (Maltby J R 2006)
During the early years of anaesthesia patients were encouraged to take oral fluids but not food on the day of surgery (Lister J 1883)
In 1920 in Britain clear fluids in the form of china tea, hot glucose water or beef tea were given 3 hour before surgery (Buxton DW 1920)
Prolonged fasting is an inappropriate way to prepare for the stress of surgery prolonged fasting prior to surgery is detrimental for the patients...