Surgeon-performed bedside ultrasound to assess volume status: a feasibility study

Rapid assessment of volume status in children is often difficult. The purpose of this study was to evaluate the feasibility of surgeon-performed ultrasound to assess volume status in patients with hypertrophic pyloric stenosis.

Ultrasounds were performed on admission and before operation. The diameters of the inferior vena cava (IVC) and aorta (Ao) were measured and IVC/Ao ratios were calculated. Electrolytes were measured on admission and repeated if warranted. Logistic regression was used to associate the clinical outcome, defined as CO2 ≤30 mEq/L, with IVC/Ao ratios. Predictive capacity was estimated from the logistic regression for IVC/Ao ratios. Linear regression was used to estimate associations between CO2 values and IVC/Ao ratios.

Thirty-one patients were enrolled. The IVC/Ao ratio is highly associated with actual CO2 values (P < 0.001) and the clinical outcome (P = 0.004). For every 0.05 unit increase in IVC/Ao ratio, predicted CO2 decreased 1.1 units. For every 0.05 unit increase in the IVC/Ao ratio, the odds of having a CO2 ≤30 mEq/L increased 48% [OR = 1.48, 95% CI (1.13,1.94)]. Predictive capacity is maximized at an IVC/Ao ratio of 0.75 as 83.9 % of subjects were correctly classified and specificity and PPV = 100%.

Surgeon-performed ultrasound to determine IVC/Ao ratio is feasible. An IVC/Ao ratio of 0.75 predicted adequate resuscitation.