Gastric Ultrasound in ED Procedural Sedation: A Game-Changer for Aspiration Risk Assessment?
Dr Himanshu Gul Mirani (Emergency Medicine Consultant),
Mr Prabhjeet Singh (Orthopaedics Registrar)
Case Presentation:
A 38-year-old male patient presented with a closed trimalleolar ankle fracture with dislocation and threatened skin. Given the risk of skin necrosis, joint reduction was deemed an emergency procedure. However, the patient had consumed a toast approximately an hour before assessment in the resuscitation room. Gastric ultrasound revealed solid contents in the stomach with no evidence of liquid content (thus not amenable for aspiration via NG).
Current RCEM guidelines do not require fasting before procedural sedation. However, the presence of solid gastric contents warranted caution. Intubation was deemed unnecessary, as definitive surgery was unlikely before the next day. Immediate extubation in the ED post- reduction still carried an aspiration risk, while prolonged ventilation would impose an unwarranted burden on critical care resources. Administering general anaesthesia was therefore not considered a prudent option.
An initial attempt at reduction with Entonox was unsuccessful. After obtaining informed consent, procedural sedation with ketofol (a combination of ketamine and propofol) was administered. The reduction was then successfully performed, and a cast was applied.
Gastric Ultrasound in ED Procedural Sedation: A Game-Changer for Aspiration Risk Assessment?
Management and Outcome:
This case underscores the value of gastric ultrasound in assessing aspiration risk beyond standard fasting times. Fasting duration alone is an unreliable indicator, as multiple factors influence gastric emptying, including medications such as glucagon-like peptide-1 (GLP-1) receptor agonist, which are increasingly being used for weight management, opiates etc. Additionally, patient-reported fasting times, the nature of ingestions and the respective quantities may be inaccurate. These can significantly impact gastric fullness assessment.
Gastric ultrasound provides real-time assessment of gastric volume and content, also allowing clinicians to determine whether NG tube aspiration could be beneficial. When liquid contents are identified, nasogastric aspiration may be an option in the arsenal to reduce gastric volume and mitigate aspiration risk. However, in this case, since only solid content was visualized and no liquid was present, NG aspiration was not considered.
By measuring the cross-sectional area of the antrum and applying validated equations, estimated gastric volume can be calculated. Aspiration risk is generally considered low when gastric volume is less than 1.5 mL/kg.
Key Learnings and Points:
This case highlights the potential role of gastric ultrasound in guiding procedural sedation decisions in the ED. Beyond determining fasting status, gastric ultrasound can identify patients who may benefit from NG aspiration to further reduce aspiration risk. Future research should focus on validating its routine use to optimize patient safety while minimizing unnecessary delays in emergency interventions.