DOI: 10.1093/bjs/znad258.366 ISSN:

819 ELLIPSE: Electrical Impedance Analysis in Patients Undergoing Emergency Abdominal Surgery

R Aftab, L Matthews, S Wooton, M Edwards
  • Surgery



An ageing population represents greater operative risk; therefore, preoperative risk stratification is required to allow patients to make an informed decision. One method of risk stratification is bioelectrical impedance analysis (BIA) which can provide information such as muscle and fat mass, providing a proxy for patient metabolic health.


Metabolic health is intrinsically linked to outcomes following surgery. We hypothesised that BIA is a feasible method of assessing patients undergoing emergency abdominal surgery and predicting postoperative outcomes.


A BIA analyser was used to measure patients body composition. All adult patients who met the National Emergency Laparotomy Audit (NELA) inclusion criteria were prospectively recruited and followed up until 30 days postoperatively. These patients had serial BIA measurements and compared with a healthy population. The phase angle (PA) is a raw variable which can be standardised to a healthy reference population and matched for age and gender. In summary, a higher phase angle is associated with improved outcomes.


31 patients were recruited and BIA analysis in patients undergoing emergency abdominal surgery was feasible. Patients with a phase angle lower than the reference population had a greater incidence of complications (p = 0.03) and had more severe complications (p = 0.023). Furthermore, the same patients also had a significantly higher NELA morbidity percentage (p = 0.022).


Our study shows that conducting BIA analysis in patients undergoing emergency abdominal surgery is feasible. The presence and severity of complications correlates with the phase angle. This represents a successful proof of concept study of BIA to predict postoperative outcomes.

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