The predictive value of airway occlusion pressure at 100 msec (P0.1) on successful weaning from mechanical ventilation: A systematic review and meta-analysis.

PURPOSE: The predictive value of airway occlusion pressure at 100 milliseconds (P0.1) on weaning outcome has been controversial. We performed a meta-analysis to investigate the predictive value of P0.1 on successful weaning from mechanical ventilation. MATERIALS AND METHODS: We searched MEDLINE, Cochrane Central Register of Controlled Trials, and EMBASE, and two authors independently screened articles. The pooled sensitivity, specificity and the summary receiver operating characteristic (sROC) curve were estimated. Diagnostic odds ratio (DOR) was calculated using meta-regression analysis. RESULTS: We included 12 prospective observational studies (n = 1089 patients). Analyses of sROC curves showed the area under the curve of 0.81 (95% confidence interval (CI): 0.77 to 0.84) for P0.1. The pooled sensitivity and specificity were 86% (95% CI, 72 to 94%) and 58% (95% CI, 37% to 76%) with substantial heterogeneity respectively. DOR was 20.09 (p = 0.019, 95%CI: 1.63-247.15). After filling the missing data using the trim-and-fill method to adjust publication bias, DOR was 36.23 (p = 0.002, 95%CI: 3.56-372.41). CONCLUSION: This meta-analysis suggests that P0.1 is a useful tool to predict successful weaning. To determine clinical utility, a large prospective study investigating the sensitivity and specificity of P0.1 on weaning outcomes from mechanical ventilation is warranted.

Go with the flow-clinical importance of flow curves during mechanical ventilation: A narrative review.

Most clinicians pay attention to tidal volume and airway pressures and their curves during mechanical ventilation. On the other hand, inspiratory-expiratory flow curves also provide a plethora of information, but much less attention is paid to them. Flow curves chronologically show the velocity and direction of inspiration and expiration and are influenced by the respiratory mechanics, the patient's effort, and the mode of ventilation and its settings. When the ventilator setting does not synchronize with the patient's respiratory pattern, the patient can easily have worsening breathing effort, patient-ventilator asynchrony, which can lead to prolonged ventilator support or lung injury. The information provided by the flow curves during mechanical ventilation, such as respiratory mechanics, the patient's effort, and patient-ventilator interactions, are very helpful when adjusting the ventilator setting. If clinicians can monitor and assess the flow curves information appropriately, it can be a useful diagnostic and therapeutic tool at the bedside. There may be association between inspiratory effort and flow, and this may further guide us, especially in the weaning process and when patients are not synchronizing with the ventilator. In this review, we try to gather information about "flow" that is scattered around in the literature and textbooks in one place. We will summarize the different flow waveforms utilized in commonly used ventilator modes with their advantages and disadvantages, information gained by the flow curves (i.e., flow-time, flow-volume, and flow-pressure), how to detect and manage asynchronies, and some ideas for future uses. Flow waveforms shapes and patterns are very beneficial for the management of patients undergoing mechanical ventilatory support. Attention to those waveforms can potentially improve patient outcomes. Clinicians should be familiar with this information and how to act upon them.