Our observational study showed that a significant portion of patients with evident signs of acute cardiogenic pulmonary edema within the prehospital setting did not receive BCPAP according to protocol. Only a minority of eligible patients received the BCPAP treatment from the EMS personnel. Moreover, only in 16 per cent of cases that did not receive BCPAP was a documented reason found. No complications were reported pertaining to the use of the facial mask.
The benefits of CPAP treatment for ACPE are well established in the emergency eepartment and ICU, showing significant improvement of vital parameters and reduction in endotracheal intubations, ICU/CCU admissions and mortality .
The Boussignac CPAP system is a compact and easy to use system, the feasibility and effectiveness of which within the prehospital setting have been shown in several studies [2–4]. Several studies reported that early treatment of ACPE using BCPAP reduced the number of endotracheal intubations and decreased ICU, CCU and hospital lengths of stay [5, 9–13].
Even though this study did not focus on evaluating outcome parameters of the BCPAP, we present these parameters in Table 2. There are insufficient data in this study to report difference in outcome. It is unclear if the outcomes observed reflect efficacy of the BCPAP versus no BCPAP, as the study did not aim to establish improvement in outcome. However, future studies in our population should be designed to assess whether outcome differences exist.
The EMS organisations in The Hague region implemented the BCPAP system in their standard protocol for treatment of ACPE. This observational study evaluated the use, effects and complications of BCPAP treatment by EMS personnel.
It is well known that ACPE is difficult to diagnose. Generally, differentiation between clinical signs of COPD and ACPE is considered to be difficult. When clinical signs were not obvious upon admission, the diagnosis ACPE was often supported by ancillary tests. However, we chose to exclusively include patients on clinical grounds, without benefit of chest radiography or laboratory results, to simulate diagnostic conditions in the field. Some studies suggested that diagnosis of ACPE in the prehospital setting is too difficult for EMS paramedics. Templier et al. studied the identification of ACPE by trained emergency nurses and physicians. The results show that nurses can recognise ACPE equally well as physicians, who correctly diagnosed ACPE in 77% of cases .
It is unclear why a significant portion of cases did not receive BCPAP treatment according to protocol in our study. A documented reason for not complying with the protocol was only given in 16 per cent of cases. Since the study period was shortly after the introduction, it is tempting to suggest that EMS personnel were not familiar with the treatment, or used the mask for the more severely hypoxic patients, as the median pulse oximetry in the BCPAP group was significantly lower. This could mean that a more intensive training programme is warranted to increase the use of BCPAP. EMS personnel also claimed that the mask caused discomfort for the patient and inconvenience when administering glyceryl trinitrate sublingually, as the mask has a tight fit. Regarding the mask causing discomfort, EMS paramedics affirm experiencing fewer problems when they made an effort to prepare and coach the patient to leave the mask in place. In some cases application was not possible as described in the results, but no complications were noted during treatment with the Boussignac mask.
The present study has several limitations. Firstly, data were collected retrospectively. Through stated criteria of inclusion, based on established criteria, we ensured an accurate selection of patients . Secondly, we compared patient characteristics of cases that were actually treated in conformity with the BCPAP protocol and cases that did not receive BCPAP treatment. The factors contributing to the decision to treat patients using BCPAP are largely unknown. Therefore, we cannot exclude ascertainment biases in this analysis. Thirdly, the study contains a limited number of patients.