Use of pressure muscle index to guide pressure support ventilation setting: a study protocol and statistical plan for a prospective randomised controlled proof-of-concept trial.

Introduction: Although pressure support ventilation is one of the most commonly used assisted ventilation modes in intensive care units, there is still a lack of precise strategies for setting pressure support. By performing an end-inspiratory airway occlusion, the difference between the peak and plateau airway pressure, which is defined as pressure muscle index (PMI), can be easily measured on the ventilator screen. Previous studies have shown that PMI is accurate in detecting high and low inspiratory effort. No study has been conducted to investigate the use of PMI as an indicator for setting inspiratory pressure support.

Method And Analysis: This is a study protocol for a prospective, single-centre, randomised controlled, pilot trial. Sixty participants undergoing pressure support ventilation will be randomly assigned in a 1:1 ratio to the control group or intervention group, with pressure support adjusted according to standard care or guided by the PMI strategy for 48 hours, respectively. The feasibility of the PMI-guided strategy will be evaluated. The primary endpoint is the proportion of inspiratory effort measurements within a well-accepted 'normal' range, which is predefined as oesophageal pressure-time product per minute between 50 and 200 cmHO⋅s/min, for each patient during 48 hours of pressure support adjustment.

Ethics And Dissemination: The study protocol has been approved by Beijing Tiantan Hospital (KY2023-005-02). The data generated in the present study will be available from the corresponding author on reasonable request. The results of the trial will be submitted to international peer-reviewed journals.

Trial Registration Number: NCT05963737; ClinicalTrials.org.