Mechanical Power in Predicting Weaning Outcome in Critically Ill Mechanically Ventilated Patients

INTRODUCTION: Mechanical ventilation in the ICU is vital, but prolonged use or premature weaning can lead to poor outcomes. Predicting weaning failure is crucial, given its association with ventilator-associated pneumonia, longer hospital stays, and higher mortality. Traditional evaluation methods like Rapid shallow breathing index(RSBI) and Spontaneous Breathing Trial(SBT) have limitations, with 3-19% of SBT-passed patients facing re-intubation due to inaccuracies(1). The shortcomings lie in the SBT's inability to precisely reflect airway and lung function, coupled with the subjective assessment of respiratory muscle endurance. There's a pressing need for more accurate and objective weaning assessment approaches to enhance outcomes and optimize ICU care. Objectives:To validate a Mechanical power oriented model of weaning failure in mechanically ventilated patients. MATERIALS AND METHODS: A Prospective, Obeservational study was done in Department of CCM at IGIMS, Patna. Patients above 18 yrs. and those mechanically ventilated >24hours were include. Confirmed neuromuscular disease and death prior to weaning were excluded. Data regarding demographics, co-morbidity, addiction, clinical history, and more was collected and analysed. The focus is on respiratory mechanics parameters within 24 hours before the first SBT. Parameters include tidal volume (VT), respiratory rate (RR), peak inspiratory pressure (Ppeak), plateau pressure (Pplat), positive end-expiratory pressure (PEEP), and minute ventilation (MV). The RSBI was noted before the first SBT. Vital parameters and laboratory investigations were noted. Mechanical power (MP) was calculated using Gattinoni's simplified equation. RESULTS: The results of our study showed that compared with the weaning failure group, the C(dyn) of the patients in the weaning success group was higher, while the MP, PEEP, Ppeak value was lower. Although value of MP not statistically significant (p =0.327)in success group but like previous studies cutoff of <15.0 had high likelyhood of success. DISCUSSION: MP is a unifying concept proposed by Gattinoni in the context of acute respiratory distress syndrome. MP integrates multiple factors of mechanical ventilation, like tidal volume, PEEP, Pplat, Ppeak, and respiratory rate and the total energy delivered by the ventilator to the lung parenchyma can be calculated from a combination of the these parameters. Consequently, MP could be a predictor to guide weaning from ventilation. In our study we analyzed the respiratory mechanics indexes of mechanically ventilated patients before weaning, and evaluated the relationship between MP, C(dyn)-MP, and weaning outcomes respectively, to further optimize the weaning decision.Conclusion: MP includes multiple factors related to respiratory load, such as resistance, driving pressure, lung compliance and PEEP. we found that MP before SBT (<15) had more chances of weaning success.