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Early use of non-invasive ventilation reduces mortality and further ventilatory interventions

 

In COPD patients, with acute exacerbations associated with mild - moderate respiratory acidosis NIV on the respiratory ward reduces mortality (NNT 10) and the need for intubation (NNT 8).

 

Level of Evidence: 1+(well conducted RCT with a low risk of Bias)

 

Citation/s: Plant PK. Owen JL. Elliott MW. Early use of non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease on general respiratory wards: a multicentre randomised controlled trial. Lancet. 2000 355(9219):1931-5.

Lead author's name and fax: Plant PK St James University Hospital, Leeds.

 

Three-part Clinical Question: In patients with acute exacerbations of COPD, does non-invasive ventilation on a general ward improve mortality?


Search Terms: non-invasive ventilation AND Exacerbation COPD. RCTs

 

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


The Study Patients: Acute exacerbation of COPD (respiratory rate>23, pH 7.25 -7.35 and PCO2 >6kPa) and GCS >/= 8/15. Absence of pneumothorax. Within 12 hours of admission.


Control group (N = 118; 118 analysed): Controlled oxygen to maintain SpO2 85-90%, nebulised salbutamol 5mg 4hourly, nebulised ipratopium 500microgram 6hourly, prednisolone 30mg daily for at least 5 days and an antibiotic. Aminophylline and doxapram permitted.


Experimental group (N = 118; 118 analysed): Same medications as control group plus.... Bilevel assist mode ventilator - Expiratory pressure set at 4cmH2O and inspiratory pressure set at 10cmH2O and increased by 5cmH2o to 20cmH2O or maximum tolerated for 1 hour. Oxygen entrained to keep SpO2 85 - 90%. Duration = as much as possible on day 1, 16hours on day 2, 12 hours on day 3 and discontinued on day 4

 

The Evidence:

 

Outcome

Time to Outcome

CER

EER

RRR

ARR

NNT

Mortality

in hospital

0.203

0.102

50%

0.101

10

95% Confidence Intervals:

5% to 94%

0.010 to 0.192

5 to 98

Need for intubation

In hoppital

0.271

0.153

44%

0.118

8

95% Confidence Intervals:

5% to 82%

0.015 to 0.221

5 to 68

 

 

EBM Comments:

 

1) Do the methods allow accurate testing of the hypothesis? Yes
2) Do the statistical tests correctly test the results to allow differentiation of statistically significant results? Yes
3) Are conclusions valid in light of the results? Yes
4) Did results get omitted, and why? No
5) Did they suggest areas of further research? No
6) Did they make any recommendations based on the results and were they appropriate? That NIV was feasible and effective in the respiratory ward setting but there must be rapid access to invasive ventilation for those patients who fail NIV.
7) Is the study relevant to my clinical practice? Yes – Although this study was based on ward patients many hospitals do not offer non-invasive ventilation outside of the intensive unit. Much of the work load of these units could be avoided by expanding the use of non-invasive ventilation and its early application to patients with COPD exacerbations having pH 7.25 - 7.35.
For every 10 patients receiving NIV one life will be saved and for every 8 an intubation will be avoided. This is somewhat less than in the Brochard (NEJM 1995) paper but still very significant.
8) What level of evidence does this study represent? Level 1+
9) What grade of recommendation can I make on this result alone? Grade B

10) What grade of recommendation can I make when this study is considered along with other available evidence? Grade A
11) Should I change my practice because of these results? Depends upon what you are doing now.Interestingly the intervention only added an extra 26mins of nursing time to the first 8 hours of admission and no difference after that. The length of hospital stay did not alter between the two groups.
There was a high degree of acceptance of NIV by the patients - established (i.e. > 1 hour usage) in 93% and a median time of 8 hours usage in the first 24 hours.
12) Should I audit my current practice because of these results? Yes – all Intubated patients due to exacerbation of COPD should be audited as to their ‘pre’ ICU care.

 

 

Appraised by: Ewan Jack University department of anaesthesia Glasgow Royal Infirmary 0141 211 4625; 15 November 2004


Email: ewanwendy@supanet.com

 

Edited by CC & SJM


Kill or Update By: Dec 2010

 

Citation: EBM Critical Appraisals. Scottish Intensive Care Society EBM Group. Jack E. 2005. : Plant PK. Owen JL. Elliott MW. Early use of non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease on general respiratory wards: a multicentre randomised controlled trial. Lancet. 2000 355(9219):1931-5.
 

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