[Influence of pressure- and volume-controlled ventilation on pulse pressure variations: randomized study]. / Influence du mode de ventilation sur la variation respiratoire de la pression pulsée artérielle: étude randomisée.

OBJECTIVE: Pulse pressure variation (ΔPP) has been demonstrated to be an accurate dynamic parameter to predict fluid responsiveness. However, the impact of different ventilator modes on this parameter is unknown. We compared ΔPP values calculated alternatively during pressure- and volume-controlled ventilation. STUDY DESIGN: Double-blind randomized study, cross-over design. PATIENTS: Patients in intensive care unit after a cardiac surgery. METHOD: Patients were ventilated alternatively in both ventilator modes (according to the randomization): volume-controlled ventilation (VVC) and pressure-controlled ventilation (VPC). Other parameters of ventilation were identical. ΔPP values were calculated for each patient in both ventilator modes. RESULTS: Among the 26 patients analyzed, mean ΔPP value was de 14.0±7.3% in VVC and 11.8±6.2% in VPC (P<0,0001). On Bland-Altman representation, mean bias was +2.2±2.3% and inferior and superior limits of agreement were respectively -2.3 and 6.7%. Arterial blood pressure and central venous pressure were not modified. CONCLUSION: ΔPP values obtained with both ventilator modes were not interchangeable. On average, ΔPP decreases by more than two points in the passage VVC to VPC for a given patient, all others things being equal.