Respiratory therapists (RTs) must understand the variables that may cause gastric inflation during bag-valvemask and mouth-to-mouth ventilation. Given the clinical responsibility RTs assume in providing ventilation with a bag-valve-mask during resuscitation of cardiac arrest victims and prior to emergent tracheal intubation, they should lead the way in minimizing gastric inflation. The article in this month's issue of RESPIRATORY CARE by Dr Fitz-Clarke 1 provides a predictive model that explains the factors that determine whether gastric inflation may occur. Health care professionals should be aware of the mouth pressure that will open the lower esophageal sphincter and how it may be affected during resuscitation, depending on degree of hypoxia, lung volume, diaphragmatic mechanics, abdominal pressure, and gastric distention. 1,2 The combination of these physical and anatomical variables and ventilatory techniques during bag-valve-mask and mouth-to-mouth ventilation determines upper airway pressure and therefore gas distribution between the lungs and stomach. 2-4 An early study on gastric inflation was conducted by Ruben et al in 1961, 3 who studied the minimum pressure needed to inflate the stomach in 20 anesthetized subjects prior to surgery, both before and after intubation. They reported that, with the head in the normal position, pressures Ͻ 15 cm H 2 O rarely produced insufflation of the stomach, while pressures Ն 25 cm H 2 O did in most subjects. 3 In an unprotected airway, distribution of ventilation volume between the lungs, esophagus, and stomach depends mainly on patient variables such as lower esophageal pressure (LESP), mouth pressure, airway resistance, and respiratory system compliance (C RS). Gastric inflation may contribute to gastric regurgitation with resultant aspiration, which was observed in 12% of subjects resuscitated for cardiac arrest where a bag-valvemask was used to provide ventilatory support. 5 The objective of the predictive model presented by Dr Fitz-Clarke aimed to improve the understanding of the optimal bag-valve-mask and mouth-to-mouth ventilation