A pilot study of the epidemiology and associations of pulse pressure variation among non-cardiac surgery critically ill patients.

BACKGROUND

A pulse pressure variation (PPV) ≥ 13% of mean arterial pressure (MAP) is an accepted marker of a fluid-responsive state. However, there is no study of its epidemiology and associations among non-cardiac critically ill patients.

OBJECTIVES

To conduct a pilot study of the epidemiology and associations of a PPV ≥ 13% among non-cardiac critically ill patients.

DESIGN

Prospective observational study.

SETTING

Intensive care unit of a university hospital.

PATIENTS

Cohort of 37 sedated critically ill patients undergoing mandatory ventilation.

MAIN OUTCOME MEASURES

PPV values, tidal volume and peak airway pressure, MAP, heart rate (HR) and central venous pressure (CVP) collected every 15 minutes; fluid balance collected hourly; correlation between PPV and these variables.

RESULTS

450 PPV measurements were collated. The PPV value was ≥ 13% in 86 (19%) measurements and was observed in two consecutive measurements in 68 (15%) of cases. On multivariable analysis, mean PPV was significantly correlated with CVP (P=0.04), HR (P<0.001) and peak airway pressure (P=0.001), but not fluid balance (P=0.3).

CONCLUSIONS

Among non-cardiac surgery mechanically ventilated patients, a PPV in the fluid-responsive range was present in one-fifth of measurements and showed logical correlations with relevant haemodynamic and mechanical ventilation-related variables. Our results provide a rationale for a more comprehensive evaluation of PPV measurement in suitable critically ill patients.