of patients considered to be at risk: pH < 2.5 and volume > 25 mL in the two groups were similar (38.3% vs 38.5%). In the elective group, there were significant correlations between gastric pH and fasting time, and between gastric volume and serum gastrin and glucose concentration. In the intrapartum group, there was a weak correlation between gastric pH and volume and preoperative anxiety and glucose concentration.There were different risk factors of acid aspiration syndrome between elective and intrapartum Cesarean deliveries, in spite of a similar overall risk of this complication. Therefore, prophylaxis for acid aspiration should be considered in each patient according to the risk factors in elective and intrapartum cases.
Internal or external diameter?To the Editor: We read with interest the report by Dillier et al. 1 on a case of laryngeal damage in an infant caused by a too large and inappropriately designed cuffed tracheal tube.We also found a difference of 2 mm in external diameter between two tracheal tubes (produced by Rush and Mallinkrodt respectively) having the same internal diameter (5 mm; Figure).Interestingly, the American Society for Testing and Materials standards for tracheal tubes contain certain requirements for tracheal tubes (i.e., internal diame-CORRESPONDENCE