Adherence with low tidal volume ventilation in ICU.

Abstract

Background

Mechanical ventilation is a commonly employed therapy in the ICU. There is evidence that the tidal volume delivered each “breath” should be less than 8ml/kg of ideal body weight (IBW) to prevent lung injury.

Objectives/Aims

To determine how often patients in BHS ICU are exposed to tidal volumes of > 8ml/kg IBW.

Method

We recorded the tidal volumes each hour for up to the first 48 hours of mechanical ventilation in patients ventilated in our ICU over a six month period from May 1st 2019 to October 31st 2019. IBW was estimated from measurement of the patient’s demispan (half their arm span) using validated equations. We then determined the percentage of time that patients were exposed to tidal volumes of > 8ml/kg IBW in their first 48 hours of ventilation.

Results

Over the audit period we collected data on 28 episodes of mechanical ventilation from 26 patients. In every episode the patient was exposed to tidal volumes of > 8ml/kg IBW for at least one hour, and in 22 out of 28 episodes the patient was exposed to tidal volumes of > 10ml/kg IBW for at least one hour. Moreover, in 14 out of 28 episodes the patient was exposed to tidal volumes of >8ml/kg BW for more than 50% of the audited ventilation period. Finally, in 4 out of 28 episodes the patient was exposed to tidal volumes of > 10ml/kg PBW for more than 50% of the audited ventilation period.

Implications/Outcomes for Planned Research Project

This audit forms the first phase of study aiming to determine if routine measurement of demispan in ventilated patients improves adherence with low tidal volume ventilation. The results of this audit demonstrate that there is a clear need for improvement in the delivery of mechanical ventilation within BHS ICU.

Final Thoughts

Poor adherence to low tidal volume ventilation has been shown to be a problem within several Victorian ICUs and may be a problem worldwide. Our study will hopefully demonstrate a strategy to improve low tidal volume ventilation that may be helpful in our ICU and others.