The utility of limited trans-thoracic echocardiography in the stratification of pulse pressure variation: A feasibility study in major open abdominal surgery

BACKGROUND AND AIM: Limitation in use of pulse pressure variation (PPV) in predicting fluid responsiveness (FR) in hypotensive patients is encountered when values are in the “gray zone” (8–13%). Dynamic arterial elastance (E(adyn)= PPV/SVV) can be used in such situations to predict arterial pressure response to volume expansion (VE). In our study, we used respiratory variation of ascending aorta velocity time integral (AoVTI) calculated from suprasternal window as a surrogate of stroke volume variation (SVV). Fluids/vasopressors were administered to hypotensive patients intraoperatively based on value of E(adyn). Aim was to assess feasibility and utility of suprasternal echocardiography in the above-mentioned subset of patients. MATERIALS AND METHODS: Hemodynamic data were monitored and respiratory variation in AoVTI was recorded using suprasternal echocardiography at all time points when patients developed hypotension (systolic blood pressure <90 mm Hg/<20% of baseline for 5 min) and at randomly selected time intervals when hemodynamic stability was maintained. VE with 250 ml of Ringer lactate (RL) was done in hypotensive patients with PPV value of 8–13% and E(adyn)>0.9. Increase of >15% in AoVTI after VE defined “fluid responsiveness.” RESULTS: Twenty-eight patients were enrolled, but three were excluded in view of left ventricular systolic dysfunction detected during preinduction echocardiography. Hemodynamic and echocardiographic data were recorded at 538 observation points in 25 adults. Hypotension occurred in 247 data sets, and in 168 data sets, value of PPV was 8–13%. VE was carried out in only those 131 data sets in which the value of E(adyn) was >0.9. Area under the curve (AUC) for VE as an intervention in the indeterminate (PPV 8–13%) group was 0.574 (0.49–0.68, 95% CI, P < 0.049), and in the observation set with PPV >13, the AUC value was 0.7 (0.59–0.98, 95% CI, P < 0.01). CONCLUSIONS: Echocardiography using the suprasternal window in the operating room during abdominal surgery is feasible, but the utility of E(adyn) in stratification of patients with PPV 8–13% is inconclusive.