Setting up the ventilator

Published Date: 19th July 2016

Publication Authors: , McBeath K,

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Background

We aimed to see if patients were being set up on the ventilator appropriately, with a tailored ventilation strategy including evidence based tidal volumes.

Methods

A quality improvement project of patients receiving mechanical ventilation (MV) on the ICU over a 6 month period. Patients admitted for organ donation and those ventilated for less than 1 hour were excluded. Using patient records, the following information was recorded on all eligible patients; ideal body weight (IBW) calculation from ulnar length, ventilator mode, tidal volume, positive end expiratory pressure (PEEP) and ventilator rate all at 1 hour of initition of MV. The primary outcome measure was ‘yes’ or ‘no’ as to whether the patient had at least 2 of these parameters changed from the default settings by 1 hour. This was agreed to represent some form of tailored ventilation strategy. The default settings on the unit ventilators are as follows: pressure-regulated volume control (PRVC), 500mls tidal volume, 5cmH20 PEEP, rate 15/min.

Results

One hundred and seventy six (176) patients were eligible for data collection. Of these 10 were excluded.Of the 166 included patients, 30% (n=49) had not had at least 2 settings modified on the ventilator by 1 hour (figure 1). Furthermore 27% (n=45) were still receiving the default 500mls tidal volume at 1 hour (figure 2). We also found that only 32% of patients being ventilated had ideal body weights calculated in the notes (n=53). From those who did, we calculated an average IBW of 64.7kg, which equates to recommended(1) tidal volume of 388mls (6mls/kg). The largest patient who had a calculation had an IBW of 82kg (equating to 492mls tidal volume).

Conclusion(s)

Given the large number of patients remained on largely default settings and those still receiving 500mls tidal volume after 1 hour of ventilation, we conclude that too often patients on the unit aren't receiving a tailored, evidence based(1) ventilation strategy. Furthermore, given that the recommended tidal volume for the average patient in our study was 388mls, and for the largest was 492mls, we conclude that the default setting of 500mls is too high, and recommend this be reduced accordingly to comply with the evidence

 

Keough, J; McBeath, K; Sim, K. (2013).  Setting up the ventilator: Don't default! A quality improvement project looking at initial ventilation on the intensive care unit . European Journal of Anaesthesiology. 30 (Suppl 51), 182

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