This column reviews the results of three papers that systematically evaluated literature to determine the value of non-invasive positive pressure ventilation (NIPPV) such as continuous positive airway pressure (CPAP) and bi-level positive airway pressure (Bi-PAP).
1. Williams T, Finn J, Perkins GD, et al. Prehospital continuous positive airway pressure for acute respiratory failure: A systematic review and meta-analysis. Prehosp Emerg Care. 2013;17(2):261–273.
2. Vital FMR, Ladeira MT, Atallah ÁN. Non-invasive positive pressure ventilation (CPAP or bilevel NIPPV) for cardiogenic pulmonary oedema. Cochrane Database Syst Rev. 2013;5: CD005351.
3. Williams B, Boyle M, Robertson N, et al. When pressure is positive: A literature review of the prehospital use of continuous positive airway pressure. Prehosp Disaster Med. 2013;28(1):52–60.
The EMS Science
1. Five studies (1,002 patients)—three randomized controlled trials, a nonrandomized comparative study and a retrospective comparative study using chart review—met the selection criteria. Forty-seven percent of the patients were allocated to the CPAP group. Baseline characteristics were similar between groups. The pooled estimates demonstrated significantly fewer intubations and lower mortality in the CPAP group.
2. Compared with standard medical care, NIPPV significantly reduced hospital mortality and endotracheal intubation. There was no difference found in hospital length of stay with NIPPV; however, intensive care unit stay was reduced by one day. Compared with standard medical care, significant increases in the incidence of acute myocardial infarction with NIPPV during its application or after were not observed. Fewer adverse events with NIPPV use were identified (in particular progressive respiratory distress and neurological failure [coma]) when compared with standard medical care.
3. The literature search located 1,253 articles, 12 of which met the inclusion criteria. The majority of studies found that the use of CPAP therapy in the prehospital environment is associated with reduced short-term mortality as well as reduced rates of endotracheal intubation.
Doc Keith Wesley Comments:
These three papers represent the current state of the science as it relates to NIPPV, of which CPAP is a form. Anyone wanting to save the time of reviewing hundreds of papers on the subject simply needs to review these three.
Although there’s some overlap of reviewed studies, there are unique differences. All three came to the same conclusion: There’s convincing evidence CPAP significantly decreases the need for intubation and increases the survival rate from respiratory failure.
Additionally, they each support the value of CPAP for all causes of respiratory failure including chronic obstructive pulmonary disease (COPD) and pulmonary edema. And finally, none of them found any evidence CPAP is harmful.
With such overwhelming evidence to support a specific medical therapy, why has CPAP not become the standard of EMS care for all levels?
If there were a medical therapy that doubled the survival from cardiac arrest, the AHA and every other professional organization would be demanding state and nation-wide legislation mandating its use. Perhaps we need to take the same approach to respiratory failure and celebrate our successes like we do with cardiac arrest.
Maybe we need to examine the admissions of every congestive heart failure patient and count the millions of healthcare dollars saved by the reduction of ICU days.
Perhaps we simply need to get our act together and petition every potential organization that has a stake in the outcomes of these patients to formally endorse prehospital CPAP and develop evidence-based protocols for its use.
Medic Karen Wesley Comments:
After all these years, I think I could give Doc’s “CPAP for Everyone” lecture. Not because I have heard it so often, but because of my experience with CPAP in the prehospital setting.
The studies in this column all clearly indicate the value of CPAP in the outcome of our patients. So I have to wonder, why—with surmounting evidence—is this procedure not used? Many states have approved CPAP, but a lack of “buy in” at the local level continues.
Our scope of practice at all levels must remain fluid to meet the needs of the patients we care for. Is it service directors or, worse yet, medical directors who are stonewalling this procedure for their patients?
In reviewing the newest CPAP devices, I see all kinds of very affordable and reliable models. Cost cannot be used as an excuse.
If it’s a case of providers “not knowing what they don’t know,” it’s time the medical directors and service directors educate their services to a procedure that really can make a difference.