• 
• 

Three Part Question

In [non-obese patients presenting with severe hypoxia], should [Non-invasive Ventilation] be [routinely used as the first-line method of pre-oxygenation before intubation in order to prevent desaturation]?

Clinical Scenario

A non-obese 68-year-old man is brought to the emergency department by his family with a history of progressive dyspnea over the last week; he has both a productive cough and a fever. He’s very confused and non-combative. His initial saturation is 84% with a reservoir oxygen mask; he is tachypneic with a respiratory rate of 35. You decide to intubate this patient and you need to optimize his saturation before induction. One of your colleagues suggests that you should try Continuous Positive Airway Pressure (CPAP) prior to intubating him. You have not yet used this technique in similar situation. You wonder if CPAP should be used as a means of optimizing oxygenation in non-obese patients with hypoxia before intubation.

Search Strategy

Search conducted on October 26th, 2013
A. The website BestBet.org was searched. No Best-Bet was found on this topic.
B. The website cochrane.org was searched. No review article was found.

C. MEDLINE (PubMed)
1) “noninvasive positive pressure ventilation”[MeSH term] OR “non-invasive positive pressure ventilation” OR “non invasive positive pressure ventilation” OR “noninvasive ventilation” OR “non-invasive ventilation” OR “non invasive ventilation” OR “bipap” OR “cpap” OR “nippv” OR “nppv” OR “peep valve” OR “continuous positive airway pressure” = 14887
2) “pre-oxygenation”[MeSH term] OR “preoxygenation” = 448
3) 1 AND 2 = 32
4) Filters: Humans, English or French = 22
5) Filters: Meta-analysis, RCT, systematic reviews = 8
6) Following an abstract review, 1 articles were selected. The other 6 articles either proved irrelevant to the subject or involved obese patients.


D. EMBASE
1) ((pre-oxygenation OR preoxygenation) AND (nppv OR continuous positive airway pressure OR noninvasive positive pressure ventilation OR non-invasive positive pressure ventilation OR non invasive positive pressure ventilation OR noninvasive ventilation OR non-invasive ventilation OR bipap OR nippv OR peep valve OR non invasive ventilation OR cpap)) = 88
1) Limits: Humans, French or English = 61
2) Limits: RCT, meta-analysis, systematic review = 16 articles were screened for relevance
3) Following an abstract review, 1 article was selected. The other 15 articles were either already found in pubmed, irrelevant to the subject or were involving obese patients.

Search Outcome

2 articles had relevancy to the question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Baillard et al. 2006 France	53 hypoxemic, critically ill patients requiring orotracheal intubation Obese patients were not excluded, however, mean body mass index was calculated at 25 kg/m2	RCT prospective from 2004 to 2005 in two hospitals Patients were randomized to NIV or BVM for their pre-oxygenation	Mean drop in SpO2 during ETI	During intubation lower SpO2 was observed in control group	•Small number of patients •Not blinded •Small spectrum of disease (acute respiratory failure only)
			SpO2 at the end of 3-min pre-oxygenation	At the end of pre-oxygenation, SpO2 was higher in the NIV group
			SpO2 5-min after intubation	Five minutes after intubation, SpO2 was better in NIV group
Herriger et al. 2004 Switzerland	40 ASA I-II elective operative patients Body mass index > 25 kg/m2 were excluded	Single center RCT Patients were randomized to CPAP or spontaneous ventilation at zero pressure	Duration of apnea until SpO2 reached 90 %	Non-hypoxic apnea duration was longer in the PEEP group compared to ZEEP group	•Small number of patients •Single center study •Not blinded •Study performed on healthy patients •CPAP applied during pre-oxygenation/PEEP applied during initial phase of artificial ventilation in group intervention vs. nothing for the control group.

Comment(s)

Data supporting the use of non-invasive ventilation as a method of pre-oxygenation in a non-obese patient presenting with a hypoxia and needing intubation in the Emergency Department are limited. Only one of the 3 studies found included hypoxemic patients and none were conducted on emergency department patients. In those studies involving small number of patients, CPAP as pre-oxygenation method seemed to be safe, simple to use and ensured better SpO2 and PaO2 values during tracheal intubation as compared with the usual pre-oxygenation method.

Clinical Bottom Line

Non-Invasive Ventilation (applied during 3 min before ETI) may be considered as a method of pre-oxygenation in non-obese patients presenting with a hypoxia and needing intubation in the Emergency Department in order to prevent desaturation. However, further studies are needed to confirm the benefits of NIV use for pre-oxygenation in selected patients and potential benefits on morbidity/mortality.

References

1. Baillard, C., et al. (2006) Noninvasive ventilation improves preoxygenation before intubation of hypoxic patients." Am J Respir Crit Care Med 174(2): 171-177
2. Herriger, A., et al. (2004) The effect of positive airway pressure during pre-oxygenation and induction of anaesthesia upon duration of non-hypoxic apnoea Anaesthesia 59(3): 243-247.