Continuous positive airway pressure and noninvasive ventilation in prehospital treatment of patients with acute respiratory failure: a systematic review of controlled studies.

Continuous positive airway pressure (CPAP) and noninvasive ventilation (NIV) are frequently used inhospital for treating respiratory failure, especially in treatment of acute cardiogenic pulmonary edema and exacerbation of chronic obstructive pulmonary disease. Early initiation of treatment is important for success and introduction already in the prehospital setting may be beneficial. Our goal was to assess the evidence for an effect of prehospital CPAP or NIV as a supplement to standard medical treatment alone on the following outcome measures; mortality, hospital length of stay, intensive care unit length of stay, and intubation rate. We undertook a systematic review based on a search in the three databases: PubMed, EMBASE, and Cochrane. We included 12 studies in our review, but only four of these were of acceptable size and quality to conclude on our endpoints of interest. All four studies examine prehospital CPAP. Of these, only one small, randomized controlled trial shows a reduced mortality rate and a reduced intubation rate with supplemental CPAP. The other three studies have neutral findings, but in two of these a trend toward lower intubation rate is found. The effect of supplemental NIV has only been evaluated in smaller studies with insufficient power to conclude on our endpoints. None of these studies have shown an effect on neither mortality nor intubation rate, but two small, randomized controlled trials show a reduction in intensive care unit length of stay and a trend toward lower intubation rate. The risk of both type two errors and publication bias is evident, and the findings are not consistent enough to make solid conclusion on supplemental prehospital NIV. Large, randomized controlled trials regarding the effect of NIV and CPAP as supplement to standard medical treatment alone, in the prehospital setting, are needed.

A systematic review of controlled studies: do physicians increase survival with prehospital treatment?

BACKGROUND: The scientific evidence of a beneficial effect of physicians in prehospital treatment is scarce. The objective of this systematic review of controlled studies was to examine whether physicians, as opposed to paramedical personnel, increase patient survival in prehospital treatment and if so, to identify the patient groups that gain benefit. METHODS: A systematic review of studies published in the databases PubMed, EMBASE and Cochrane from January 1, 1990 to November 24, 2008. Controlled studies comparing patient survival with prehospital physician treatment vs. treatment by paramedical personnel in trauma patients or patients with any acute illness were included. RESULTS: We identified 1.359 studies of which 26 met our inclusion criteria. In nine of 19 studies including between 25 and 14.702 trauma patients in the intervention group, physician treatment increased survival compared to paramedical treatment. In four of five studies including between nine and 85 patients with out of hospital cardiac arrest, physician treatment increased survival. Only two studies including 211 and 2.869 patients examined unselected, broader patient groups. Overall, they demonstrated no survival difference between physician and paramedical treatment but one found increased survival with physician treatment in subgroups of patients with acute myocardial infarction and respiratory diseases. CONCLUSION: Our systematic review revealed only few controlled studies of variable quality and strength examining survival with prehospital physician treatment. Increased survival with physician treatment was found in trauma and, based on more limited evidence, cardiac arrest. Indications of increased survival were found in respiratory diseases and acute myocardial infarction. Many conditions seen in the prehospital setting remain unexamined.