Use of the product of driving pressure and respiratory rate for predicting failure of weaning from mechanical ventilator in medical patients

Abstract

Background: Respiratory workload increment in the process of mechanical ventilation withdrawal is critical for the determination of weaning outcome. Pressure, tidal volume (Vt) and respiratory rate (RR) are considered as patient’s respiratory power, albeit being affected by excessive respiratory load. We aimed to evaluate the performance of driving pressure (DP)×RR to predict the outcome of weaning.Methods: Plateau pressure (Pplat) and positive end-expiratory pressure tot (PEEPtot) were measured during mechanical ventilation, viz., (1) brief deep sedation, (2) on volume support ventilation of MV with Vt 6 ml/kg and a PEEP of 0 cm H2O, (3) Pplat and PEEPtot were measured by holding breath for 2s after inhalation and exhalation, respectively. The DP was determined as Pplat minus PEEPtot. The highest RR was recorded within 3 min during spontaneous-breathing trial (SBT). Patients that were able to tolerate SBT for 1 h were extubated.Results: Out of the 61 patients studied, 22 failed weaning. During the withdrawal of ventilation, DP×RR was 134.2±33.2 cmH2O·breaths/min and 238.5±61.7 cmH2O·breaths/min (P=0.00), DP was 7.9±1.6 cmH2O and 9.7±2.3 cmH2O (P=0.00), in the “success” and “failure” groups, respectively. The DP×RR index greater than 170 cmH2O·breaths/min had a sensitivity of 95.5% and a specificity of 89.7%, while DP index greater than 8.1 cmH2O had 81.8% sensitivity and 64.1% specificity to predict weaning failure.Conclusions: Measurement of DP×RR during withdrawal of ventilation may help predict weaning outcome. Noticeably, high DP×RR increased the likelihood of weaning failure.