Assessment of risk factors related to the acid aspiration syndrome in pediatric patients - pH and residual volume

Abstract

Fifty-one ASA physical status I children ages 3-17 years were randomly chosen for this study. Group I (n=16) consisted of children anesthetized for the first time; all were inpatients. Group II (n=16) consisted of pediatric outpatients anesthetized for the first time. Group III (n=19) consisted of children who had been hospitalized and anesthetized on multiple occasions; all of this group were plastic surgical patients at least one year post-acute burn injury. No patient had a known history of ulcer disease or was taking a medication that would interfere with gastric emptying. The level of anxiety prior to induction was assessed by a physician not involved in the study. Each patient was scored as either anxious or comfortable. Fifty of 51 pediatric patients between the ages of 3 and 17 years had a gastric pH of 2.5 or less; one had a pH of 2.6. There was no significant difference in age or weight between any two groups. The mean age was 10.2 years and the mode 8 years. There was no difference in the degree of anxiety among Groups I to III. There was no statistical difference in gastric volume or pH comparing inpatients to outpatients, or multi-anesthetized to single anesthetized patients. There was no difference in gastric volume comparing the anxious to the comfortable patient; however, comfortable patients had a significantly greater acid content (pH 1.38 ± 0.05 vs 1.6 ± 0.06; P<0.005). The range of gastric volume was quite large, from 0.11 ml/kg to 4.72 ml/kg. The overall mean gastric residual for all patients was 0.78 ± 0.1 ml/kg with a pH of 1.45 ± 0.03. The results are discussed.