Gastric Ultrasound in Pediatric Trauma Patients

Overview

Gastric ultrasound has become increasingly utilized to examine volume and quality of gastric contents in the preoperative setting to guide anesthetic management and relay risk of aspiration in both adult and pediatric medicine. Gastric fluid volumes in trauma patients are thought to be elevated due to delayed gastric emptying in the setting of an over-attenuated sympathetic response to physical pain and stress, opioid analgesia, and other associated injuries (traumatic brain). However, there is a paucity of literature examining gastric fluid volumes (GFV), measured by gastric ultrasound, in the pediatric trauma population. The purpose of the study is to assess whether preoperative gastric ultrasound is an accurate method to identify pediatric trauma patients who have elevated GFV (\>0.8mL/kg) and high-risk gastric contents (solids, complex liquids, in addition to large volumes).

There is longstanding evidence that GFV are elevated in trauma patients for several physiologic reasons. This has been corroborated in both adult and pediatric studies, suggesting that trauma patients may be at higher risk for gastric aspiration compared to healthy controls, and that anesthetic management should reflect this elevated risk. This often implies tracheal intubation with or without a rapid sequence induction. However, performing rapid sequence induction to decrease aspiration risk increases the risk of desaturation, hypoxia, bradycardia, and hemodynamic instability, especially in small children who have reduced functional residual capacity and who are difficult to adequately preoxygenate. This has presented a question-mark for anesthesia providers caring for children with traumatic injuries, and variations in practice. Bricker and authors examined gastric fluid volumes by aspiration of gastric contents in 1989 in pediatric trauma patients, and found that nearly 50% had elevated gastric contents and were at risk for potential aspiration, though no aspiration events were captured. Likewise, Schurizek and authors looked a cohort of pediatric patients presenting for emergency surgery, which included trauma, and found the nearly 38% of children presenting to the OR who had adequately fasted had elevated gastric contents. A recent study using gastric ultrasound in children with proximal limb fractures found a similar rate of elevated gastric contents with 37% of children meeting criteria, and 24% of those showing evidence of solids/complex gastric fluid. Again, no aspiration events were captured. Thus, little is known to inform anesthesiologists about which risk factors contribute to high gastric volumes in pediatric trauma patients or how long these children may be considered at additional risk for aspiration. Aspiration is an extremely rare event, typically estimated between 1-5/10,000 anesthetics or 0.01%, and the sample size needed to power a study to capture reducing the risk of aspiration is not feasible. Thus, the investigators hope to characterize gastric contents/GFV using ultrasound in pediatric trauma patients presenting with a wide variety of traumatic injury and at varying times from injury (urgent/emergent surgery versus semi-urgent surgery), to identify potential risk factors and guide anesthetic management in this vulnerable population.