First of all, we would like to convey our appreciation to Dr. Cook-Sather and Dr. Salem for their scientific and detailed responses to our Letter to the Editor.1 

As Dr. Cook-Sather rightly pointed out, although studies have been conducted, and scientific data accumulated before establishing the guidelines for fasting periods, there is very limited data to definitively support a 4-h versus  a 6-h fasting period. We are of the opinion that the presence of guidelines for two different fasting times could prove problematic. After encountering this case, we changed our fasting time policy from 4 h for formula milk to 6 h, as we thought that it provided a greater safety margin for the risk of aspiration while not causing any serious disadvantage to the patients and their parents.

Dr. Salem commented that despite an adequate fasting period, infants, owing to their anatomical and physiologic differences from adults, are predisposed to regurgitation of gastric contents. Hence, they should be treated as potential risks for regurgitation and all precautionary measures to minimize this risk should be undertaken. We are in complete concurrence with this opinion.

Finally, although established guidelines cannot guarantee safety, we believe that our case report contributes to further elucidating the practical implications of these guidelines, making the induction of anesthesia even safer by further reducing the risk of regurgitation and aspiration.

* University of the Ryukyus, Okinawa, Japan.

Kawabata T, Tokumine J, Nakamura S, Sugahara K: Unanticipated vomiting and pulmonary aspiration at anesthesia induction in a formula-fed 4 month old infant. Anesthesiology 2004; 100:1330–1