Clinical Research Directory

The Million Anesthesia Cases Study (MACS) - a Cohort Study of Preoperative Fasting and Perioperative Outcomes

Perioperative fasting has historically been viewed as a low-risk intervention. However, preliminary data indicate that perioperative loss of nutrition and fluids is likely harmful. This study intends to characterize perioperative fasting practices and their potential effects on clinical outcomes through possible effects on patient well-being (anxiety, hunger, thirst), physiology (hypovolemia, hypotension), perioperative aspiration, etc. The research team hypothesized that in addition to known adverse effects on patients' well-being, prolonged preoperative fasting adversely affects circulating blood volume-related (hypotension, decreased urine output etc.) and glucose metabolism-related (e.g., hypo/hyperglycemia) perioperative physiology. The investigators will also test for an association between the duration of preoperative fasting and the risk of perioperative pulmonary aspiration. Additional knowledge on the potential adverse effects of preoperative fasting will inform preoperative fasting policies and research interventions that are relevant to hundreds of millions of patients subjected to preoperative/preprocedural fasting worldwide each year.

Sonographic Assessment of Cricoid Pressure

Examining the effectiveness of cricoid pressure using ultrasound imaging. Pulmonary aspiration of gastric contents during tracheal intubation, although rare in pediatrics, is a potentially catastrophic complication of anesthesia. Cricoid pressure is applied during rapid sequence induction to occlude the esophagus and prevent aspiration of gastric contents. Accumulating evidence in adults suggests that cricoid pressure often is not effective, either because the esophagus normally lies lateral to the cricoid cartilage, or because downward pressure on the cricoid cartilage laterally displaces (rather than compresses) the esophagus. The investigator proposes to examine the effectiveness of cricoid pressure in children in the peri-operative setting using non-invasive ultrasound imaging. Using this approach, the investigator will investigate the normal anatomical relationship of the esophagus and the cricoid cartilage, as well as how cricoid pressures influences this relationship. Further, the investigator will examine whether alternatives to downward cricoid pressure, such as laterally directed pressure, are more effective at occluding the esophagus.