Characterization of the mechanical ventilator adjustment process

Introduction

The aim of the present study was to gain insight into the mechanical ventilator adjustment process, particularly events that prompt clinicians to adjust the ventilator, the indications, considerations, and methods used to assess the successfulness of the adjustment episode.

Methods

A prospective, observational, noninterventional study was conducted in a 24-bed adult, medical and surgical intensive care unit at a regional hospital. Patient demographics, ventilator adjustment episodes, and clinical decisions related to these adjustments were collected. Clinicians were asked to complete a ventilator flowsheet before and after any ventilator adjustment episode. Simultaneously, they were asked to complete an open-ended questionnaire related to the process of ventilator adjustment episode.

Results

A total of 168 ventilator adjustment episodes derived from 26 mechanically ventilated patients were evaluated. Among these episodes, the ventilator mode was adjusted 33 times (20%), the minute volume 37 times (22%), the positive end-expiratory pressure 19 times (11%), the pressure support 21 times (12%), and the fraction of inspired oxygen 61 times (36%). Triggers which stimulate the process of mechanical ventilator adjustment were categorized into: routine ventilator checks (35%), routine arterial blood gases (ABG) (20%), weaning trials (13%), and calls from nurses (9%). The most common indications to adjust the ventilator were hyperoxygenation (28%) and weaning trials (26%). Peripheral oxygen saturation, ABG, and level of consciousness were the most common considered variables during the process of ventilator adjustment. In 42% of the total adjustment episodes, clinicians did not consider any technical, physiological or psychological variable while they adjusted ventilator parameters. Clinicians based their decisions to adjust ventilator settings on clinical experience (72%), trial and error (15%), protocols (11%), and scientific equations Clinicians assessed their decisions via ABG results (47%), peripheral oxygen saturation (23%), and general patient assessment (9%).

Conclusion

The process of ventilator adjustment is mainly stimulated by routine ventilator checks and ABG. ABG and weaning trials are the most common indications. Most ventilator adjustment decisions are based on clinical experience, evaluated via ABG and peripheral oxygen saturation.