Pulse pressure variation predicts fluid responsiveness in elderly patients after coronary artery bypass graft surgery.

OBJECTIVE

To assess the ability of pulse pressure variation to predict fluid responsiveness in mechanically ventilated elderly patients after coronary artery bypass graft surgery.

DESIGN

A prospective, interventional study.

SETTING

An academic, tertiary referral hospital.

PARTICIPANTS

Sixty patients >70 years old and mechanically ventilated after coronary artery bypass graft surgery.

INTERVENTIONS

Intravascular volume expansion using 6% hydroxyethyl starch solution, 7 mL/kg over 20 minutes.

MEASUREMENTS AND MAIN RESULTS

Heart rate, arterial blood pressure, pulse pressure variation, central venous pressure, pulmonary artery occlusion pressure, and stroke volume index were measured immediately before and after volume expansion. Fluid responsiveness was defined as an increase in stroke volume index ≥ 15% after volume expansion. Forty-one patients were fluid responders and 19 patients were nonresponders. In contrast to central venous pressure or pulmonary artery occlusion pressure, pulse pressure variation was higher in the responders than in the nonresponders (22 ± 6% v 9.3 ± 3%, p = 0.001) and correlated with the percent changes in the stroke volume index after volume expansion (r = 0.47, p = 0.001). The area under the receiver operating characteristic curve for pulse pressure variation was 0.85 (95% confidence interval 0.75-0.94). The threshold value of 11.5% allowed the discrimination between responders and nonresponders with a sensitivity of 80% and a specificity of 74%.

CONCLUSIONS

Pulse pressure variation is a reliable predictor of fluid responsiveness in mechanically ventilated elderly patients after coronary artery bypass graft surgery.