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Pulmonary artery catheter versus central venous catheter in early acute lung injury (ALI)

Citation/s: The National Heart, Lung and Blood Institute Acute Respiratory Distress Syndrome (ARDS) Clinical Trials Network. Pulmonary-Artery versus Central Venous Catheter to Guide Treatment of Acute Lung Injury. NEJM 2006; 354:2213-2224

Lead author: AP Wheeler

Three-part clinical question: In patients with acute lung injury for less than 48 hours does pulmonary artery catheter guided therapy improve mortality when compared to CVC guided therapy.

Search Terms: ALI, ARDS, Therapy

The Study: Non-blinded concealed randomised controlled trial with intention-to-treat.

The Study Patients: Patients with ALI (PaO₂/FiO₂ <300mmHg) for 48 hours or less. The patients were all being artificially ventilated through a tracheal tube. Thirty five% of these patients met the criteria for shock.

Control group (N = 488; 487 analysed): (N= 488, 487 analysed): Standardised management protocol, with haemodynamic data being derived from a central venous catheter.

Experimental group (N = 513; 513 analysed): (N=513, 513 analysed): Standardised management protocol with haemodynamic data being derived from a pulmonary artery catheter, otherwise management strategy the same as the control group.

The Evidence:

Comments:

1) Do the methods allow the adequate testing of the hypothesis? Generally yes, but the study compared two methods of gathering physiological data. Not all available data was used in the PAC group as CVP and clinical examination findings were not used. Mixed venous oxygen saturations were also not measured, the ability to measure this is a possible advantage of the PAC. The method is weak to determine the likelihood of complications related to catheter insertion, as patients who already had a CVC in situ who were allocated to the CVC limb did not have any complications related to it's insertion recorded from the time of first insertion. Patients who had a PAC in situ at time of enrolment were excluded from the trial. It is possible these patients in whom a PAC is rapidly inserted are those show benefit the most.

2) Do the statistical tests correctly test the results to allow differentiation of statistically significant result? Yes

3) Are conclusions valid in light of results? Yes, the conclusions are that 60 day mortality and numbers of ventilator free days at 28 days are similar in both groups.

4) Did results get omitted, and why? No

5) Did they suggest areas of further research? Yes they recommended similar research in other patient groups including patients with heart failure, trauma and post-operative patients.

6) Did they make recommendations based on results and were they appropriate? Yes. They suggest that in patients with ALI for less than 48 hours, a PAC shows no benefit and is associated with a higher risk of harm. This is appropriate.

7) Is this study relevant to my clinical practice- Yes, this trial was carried out in patients with ALI and ARDS using international criteria and thus would seem a similar patient group to the patients treated in Scotland with ALI.

8) What level of evidence does this study represent? 1⁺

9) What grade of recommendation can I make on this result alone? B

10) What grade of recommendation can I make when this study is considered along with
other available evidence? A

11) Should I change my practice because of these results? This study demonstrates that PAC insertion in patients with ALI is not associated with improved outcome and is associated with excessive harm. If you use a PAC in these patients you should consider changing your practice.

12) Should I audit my current practice because of these results? Yes, the study suggests that whilst PACs do not give any benefit, they may give an increased complication rate. Complications secondary to insertion of PACs should be audited.

Appraised by: Peter Hersey, Aberdeen Royal Infirmary, Aberdeen, Scotland, AB25 2ZH; 18 August 2006
Email: phersey@nhs.net

Kill or Update By: 1st September 2009

Reviewed and edited by CC & BC

Citation: EBM Critical Appraisals. Scottish Intensive Care Society EBM Group. 2006. Hersey P. The National Heart, Lung and Blood Institute Acute Respiratory Distress Syndrome (ARDS) Clinical Trials Network. Pulmonary-Artery versus Central Venous Catheter to Guide Treatment of Acute Lung Injury. NEJM 2006; 354:2213-2224

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