Management of severe adult respiratory failure: evidence-based?

Introduction

The management of severe respiratory failure (SRF) remains a challenging problem. With the availability of many options with variable results, the management of patients with SRF is likely to vary between different ICUs and these practices may not necessarily be evidence-based. In this study we aimed to define the respiratory and the general management of the patients with SRF, and to identify the treatment practices that are evidence-based in the surveyed ICUs in the UK.

Methods

This study is a questionnaire survey of the ICUs that were participating or were willing to participate in CESAR http://www.cesar-trial.org, an ongoing randomised controlled trial (RCT) comparing ECMO with conventional intensive care for SRF. Although participating ICUs are free to use any modality of treatment at their discretion, the CESAR trial recommends a low tidal volume ventilation strategy according to the ARDS Network group. The collaborators of all 87 participating ICUs (out of a total of 262 ICUs in the United Kingdom) were requested to complete a postal questionnaire between February 2002 and May 2004. The response rate was 100%. A literature search for RCTs and meta-analyses of RCTs was performed to identify practices studied in this survey that were proved to improve survival in patients with SRF.

Results

The practices in the surveyed ICUs are shown below, with the percentages of the ICUs in parentheses. Practices that were proven to improve survival by at least one RCT are highlighted with an asterisk.

• Preferred mode of ventilation: pressure controlled (82%), PRVC (6%), volume controlled (7%), HFOV (5%).

• PEEP strategy: above lower inflection point (28%), best PEEP against SPO₂ (61%), other (e.g. empirical high PEEP 10–15, Best PEEP against SPO₂ and tidal volumes) (11%).

• Peak plateau pressure limitation: <30* (48%), >30 (37%).

• Practice of ARDS network group approach* (ventilation with low tidal volumes) (69%).

• Use of nitric oxide (10%); prone ventilation (91%).

• Timing of tracheotomy: within 48 hours (16)*, within 7 days (51%); percutaneous* (95%), surgical (3%).

• Routine cardiac output monitoring (63%): PA catheter (38%), oesophageal monitor (44%), other (18%); resuscitation fluid: colloids (82%).

• Target Hb: 7–9 gm*% (69%), 9–10 (14%) >10 gm% (17%).

Conclusion

Although there are variations of practices in the management of adult patients with SRF, most of the ICUs evaluated in this survey are following evidence-based practices. This should improve the survival of patients managed conventionally in the CESAR trial compared with historical results.