Preoperative fasting and plasma glucose levels in children

Implementing fasting guidelines has been a major challenge in paediatric anaesthetic practice. Unforeseen rescheduling of cases lead on to almost inevitable prolonged preoperative fasting periods. This study evaluated the correlation between fasting duration and fasting plasma glucose, and the clinical utility of signs of hypoglycemia in 56 unpremedicated children aged 0.17 to 13 years (median = 4 years) and weighing 4 to 40 kgs (median = 10.50kgs). The median (range) fasting plasma glucose was 80mgdl^-1 (54-200mgdl^-1) following a fast of 12 hours (6-19 hours). The correlation between the two was not significant (correlation coefficient r = -0.163; P = 0.230) except in the age group of 2-6 years (r = -0.505; P = 0.027). The incidence of hypoglycemia (plasma glucose <60mgdl^-1) was 3.6%. Clinical signs of hypoglycemia were found to be unreliable in diagnosing hypoglycemia (false positive rate = 66.66%). Thus long duration of preoperative fasting, though not to be recommended, may be well tolerated by older children.