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NIV in immunosuppressed patients - prevention of VAP?

Citation/s:
Gilles Hilbert, Didier Gruson et al: Noninvasive ventilation in immunosuppressed patients with pulmonary infiltrates, fever and acute respiratory failure. NEJM 2001;344:481-7
 

Lead author's name and fax: Gilles Hilbert, gilles.hilbert@chu-bordeaux.fr

Three Part Clinical Question: In immunosuppressed patients with respiratory failure, does the use of noninvasive ventilation reduce ventilator associated pneumonia when compared to standard treatment?
 

Search Terms: NIV, VAP

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

The Study Patients: Immunosuppressed patients admitted to a single ITU over a 20-month period with fever, acute respiratory failure and pulmonary infiltrates. Immunosuppression was defined as neutrophils< 1000 per cubic mm after chemo or BMT in haematological malignancy, drug induced immunosupression in transplant patients, a result of steroid or cytotoxic therapy, or AIDS. Eligible patients required a fever of >38.3, persistent pulmonary infiltrates on CXR, a deterioration of gas exchange, severe dyspnoea at rest, RR>30 and PaO2/FiO <200mmHg. Exclusions included recent failure of more than two organs, rapid deterioration in GCS (<8), haemodynamic instability (SBP <80mmHg or ischaemic ECG or significant arrhythmias), COPD,  hypercarbic (>55mmHg) acidosis (ph<7.35), uncorrected bleeding, tracheostomy.

Control group (N = 26; 26 analysed): Oxygen via venture mask to achieve O₂ sats >90%. Standard medical treatment.
 

Experimental group (N = 26; 26 analysed): The same treatment as the control group with the addition of periods of full face mask NIV. PS was adjusted to achieve a TV of 7-10ml/kg and RR</=25. FiO2 was adjusted to achieve O₂ sats>90%. Peep was increased by 2cm H₂O, to a maximum of 10cm, until the oxygen requirement was 65% or less. NIV periods were at least 45 mins alternated every 3 hours with spontaneous ventilation on oxygen. NIV resumed when O₂ sats fell to 85% or dyspnoea worsened as evident by a RR > 30.

 The Evidence:

Comments:

Do the methods allow accurate testing of the hypothesis? - The study was relatively small and there is no information as how they determined the size of the study. VAP was not an individual outcome measure and the study was probably not powered to detect a difference.
Do the statistical tests correctly test the results to allow differentiation of statistically significant results? - Yes
Are the conclusions valid in light of the results? – Yes, the concept that NIV reduces intubation and mortality in these patients is probably a valid conclusion.
Did results get omitted and why? No
Did they suggest areas of further research? No
Did they make recommendations based on the results and where they appropriate? They make statements but no recommendations.
Is the study relevant to my clinical practice? Yes, although a small group of patients in most ITUs, the results would be relevant. All ITU mortality occurred in intubated patients after the failure of NIV or standard therapy. Mortality after intubation was 83% in the NIV group and 90% in the control. All patients with a VAP diagnosis died.
What level of evidence does this study represent? Level 1⁺.
What grade of recommendation can I make on this result alone? B
What grade of recommendation can I make when this study is considered along with other available evidence? N/A – due to lack of other studies.
Should I change my practice because of these results? Yes - the potential benefit is great and the potential for harm low.
Should I audit my current practice because of these results? Yes – audit the management of these patients.

Appraised by: B Miles ,Stobhill Hospital, Glasgow; 20 May 2004
 

Email: barbara.miles.stob@northglasgow.scot.nhs.uk
 

Kill or Update By: June 2007

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