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Pressure record analysis method parameters during weaning success and failure from mechanical ventilation in
Yuankai Zhou1, Shengjun Liu1, Liangyu Mi1
1Department of Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.
Background:
Pressure recording analytical method (PRAM) parameters, derived from arterial pressure waveform analysis, provide continuous and minimally invasive assessment of cardiovascular function. This study examines the changes in PRAM parameters during the spontaneous breathing trial (SBT) in patients undergoing prolonged mechanical ventilation (PMV, defined as >24 hours) after cardiac surgery and explores their potential to predict the outcomes of SBT.
Methods:
In this prospective observational study, 58 adult patients requiring PMV (>24 h) after cardiac surgery underwent a single 60-min SBT. PRAM variables and systemic hemodynamics were recorded immediately before and throughout the trial.
Results:
Fifteen patients (25.9%) failed weaning. Generalised estimating equations revealed a significant group × time interaction for cardiac cycle efficiency (CCE) (P<0.001). In the success group, CCE changes over time were not significant, whereas in the failure group, CCE decreased significantly from pressure support ventilation (PSV) to SBT-last minute (-0.011±0.170 to -0.118±0.226, P=0.007 with Bonferroni correction). A significant interaction was also found for the maximal slope of systolic upstroke (dp/dt) (P=0.02), with dp/dt significantly decreasing at SBT-last minute in the failure group. Receiver-operating-characteristic analysis indicated moderate discrimination for CCEPSV [the area under the curve (AUC) =0.6752, 95% confidence interval (CI): 0.5345-0.8159; P=0.045]. Patients in the low-CCE quartile experienced a 40% failure rate and longer intensive care unit (ICU) stay {6 [3-7] vs. 4 [3-5] days; P=0.02} compared with the high-CCE quartile, in which no failures occurred.
Conclusions:
This study indicates that CCE and dp/dt exhibit different trends during successful and failed SBTs in prolonged ventilated patients after cardiac surgery. CCE measured during SBT and its dynamic decline show promise as indicators of weaning outcome, but these findings are preliminary. Consequently, future well-powered prospective studies incorporating multivariate adjustment are warranted to determine whether real-time CCE monitoring can serve as a reliable tool for guiding weaning and extubation decisions.
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