An observational study of noninvasive positive pressure ventilation in an out-of-hospital setting

Prehospital Noninvasive Ventilation: An NAEMSP Position Statement and Resource Document

Noninvasive ventilation (NIV), including bilevel positive airway pressure and continuous positive airway pressure, is a safe and important therapeutic option in the management of prehospital respiratory distress. NAEMSP recommends:NIV should be used in the management of prehospital patients with respiratory failure, such as those with chronic obstructive pulmonary disease, asthma, and pulmonary edema.NIV is a safe intervention for use by Emergency Medical Technicians.Medical directors must assure adequate training in NIV, including appropriate patient selection, NIV system operation, administration of adjunctive medications, and assessment of clinical response.Medical directors must implement quality assessment and improvement programs to assure optimal application of and outcomes from NIV.Novel NIV methods such as high-flow nasal cannula and helmet ventilation may have a role in prehospital care.

Management of respiratory distress following prehospital implementation of noninvasive ventilation in a physician-staffed emergency medical service: a single-center retrospective study

BACKGROUND

Noninvasive ventilation (NIV) is recognized as first line ventilatory support for the management of acute pulmonary edema (APE) and chronic obstructive pulmonary disease (COPD) exacerbations. We aimed to study the prehospital management of patients in acute respiratory distress with an indication for NIV and whether they received it or not.

METHODS

This retrospective study included patients ≥18 years old who were cared for acute respiratory distress in a prehospital setting. Indications for NIV were oxygen saturation (SpO₂) <90% and/or respiratory rate (RR) >25/min with a presumptive diagnosis of APE or COPD exacerbation. Study population characteristics, initial and at hospital vital signs, presumptive and definitive diagnosis were analyzed. For patients who received NIV, dyspnea level was evaluated with a dyspnea verbal ordinal scale (D-VOS, 0-10) and arterial blood gas (ABG) values were obtained at hospital arrival.

RESULTS

Among the 187 consecutive patients included in the study, most (n = 105, 56%) had experienced APE or COPD exacerbation, and 56 (30%) received NIV. In comparison with patients without NIV, those treated with NIV had a higher initial RR (35 ± 8/min vs 29 ± 10/min, p < 0.0001) and a lower SpO₂ (79 ± 10 vs 88 ± 11, p < 0.0001). The level of dyspnea was significantly reduced for patients treated with NIV (on-scene D-VOS 8.4 ± 1.7 vs 4.4 ± 1.8 at admission, p < 0.0001). Among the 131 patients not treated with NIV, 41 (31%) had an indication. In the latter group, initial SpO₂ was 80 ± 10% in the NIV group versus 86 ± 11% in the non-NIV group (p = 0.0006). NIV was interrupted in 9 (16%) patients due to either discomfort (n = 5), technical problem (n = 2), persistent desaturation (n = 1), or vomiting (n = 1).

CONCLUSIONS

The results of this study contribute to a better understanding of the prehospital management of patients who present with acute respiratory distress and an indication for NIV. NIV was started on clinically more severe patients, even if predefined criteria to start NIV were present. NIV allows to improve vital signs and D-VOS in those patients. A prospective study could further elucidate why patients with a suspected diagnosis of APE and COPD are not treated with NIV, as well as the clinical impact of the different strategies.

TRIAL REGISTRATION

The study was approved by our institutional ethical committee ( CER-VD 2020-01363 ).

Outcomes of Patients Treated with Prehospital Noninvasive Ventilation: Observational Retrospective Multicenter Study in the Northern French Alps

Noninvasive ventilation (NIV) improves the outcome of acute cardiogenic pulmonary edema (AcPE) and acute exacerbation of chronic obstructive pulmonary disease (aeCOPD) but is not recommended in pneumonia. The aim of this study was to assess the appropriateness of the use of NIV in a prehospital setting, where etiological diagnostics rely mainly on clinical examination. This observational multicenter retrospective study included all the patients treated with NIV by three mobile medical emergency teams in 2015. Prehospital diagnoses and hospital diagnoses were extracted from the medical charts. The appropriateness of NIV was determined by matching the hospital diagnosis to the current guidelines. Among the 14,067 patients screened, 172 (1.2%) were treated with NIV. The more frequent prehospital diagnoses were AcPE (n = 102, 59%), acute respiratory failure of undetermined cause (n = 46, 28%) and aeCOPD (n = 17, 10%). An accurate prehospital diagnosis was more frequent for AcPE (83/88, 94%) than for aeCOPD (14/32, 44%; p < 0.01). Only two of the 25 (8%) pneumonia cases were diagnosed during prehospital management. Prehospital NIV was inappropriate for 32 (21%) patients. Patients with inappropriate NIV had a higher rate of in-hospital intubation than patients with appropriate NIV (38% vs. 8%; p < 0.001). This high frequency of inappropriate NIV could be reduced by an improvement in the prehospital detection of aeCOPD and pneumonia.

Pre-hospital non-invasive ventilation for acute respiratory failure: a systematic review and cost-effectiveness evaluation

BACKGROUND

Non-invasive ventilation (NIV), in the form of continuous positive airway pressure (CPAP) or bilevel inspiratory positive airway pressure (BiPAP), is used in hospital to treat patients with acute respiratory failure. Pre-hospital NIV may be more effective than in-hospital NIV but requires additional ambulance service resources.

OBJECTIVES

We aimed to determine the clinical effectiveness and cost-effectiveness of pre-hospital NIV compared with usual care for adults presenting to the emergency services with acute respiratory failure and to identify priorities for future research.

DATA SOURCES

Fourteen electronic databases and research registers (including MEDLINE In-Process & Other Non-Indexed Citations, MEDLINE, EMBASE, and Cumulative Index to Nursing and Allied Health Literature) were searched from inception to August 2013, supplemented by hand-searching reference lists and contacting experts in the field.

REVIEW METHODS

We included all randomised or quasi-randomised controlled trials of pre-hospital NIV in patients with acute respiratory failure. Methodological quality was assessed according to established criteria. An aggregate data network meta-analysis (NMA) of mortality and intubation was used to jointly estimate intervention effects relative to usual care. A NMA, using individual patient-level data (IPD) and aggregate data where IPD were not available, was carried out to assess whether or not covariates were treatment effect modifiers. A de novo economic model was developed to explore the costs and health outcomes when pre-hospital NIV (specifically CPAP provided by paramedics) and standard care (in-hospital NIV) were applied to a hypothetical cohort of patients with acute respiratory failure.

RESULTS

The literature searches identified 2284 citations. Of the 10 studies that met the inclusion criteria, eight were randomised controlled trials and two were quasi-randomised trials (six CPAP; four BiPAP; sample sizes 23-207 participants). IPD were available from seven trials (650 patients). The aggregate data NMA suggested that CPAP was the most effective treatment in terms of mortality (probability = 0.989) and intubation rate (probability = 0.639), and reduced both mortality [odds ratio (OR) 0.41, 95% credible interval (CrI) 0.20 to 0.77] and intubation rate (OR 0.32, 95% CrI 0.17 to 0.62) compared with standard care. The effect of BiPAP on mortality (OR 1.94, 95% CrI 0.65 to 6.14) and intubation rate (OR 0.40, 95% CrI 0.14 to 1.16) compared with standard care was uncertain. The combined IPD and aggregate data NMA suggested that sex was a statistically significant treatment effect modifier for mortality. The economic analysis showed that pre-hospital CPAP was more effective and more expensive than standard care, with an incremental cost-effectiveness ratio of £20,514 per quality-adjusted life-year (QALY) and a 49.5% probability of being cost-effective at the £20,000-per-QALY threshold. Variation in the incidence of eligible patients had a marked impact on cost-effectiveness and the expected value of sample information for a future randomised trial.

LIMITATIONS

The meta-analysis lacked power to detect potentially important differences in outcome (particularly for BiPAP), the intervention was not always compared with the best alternative care (in-hospital NIV) in the primary studies and findings may not be generalisable.

CONCLUSIONS

Pre-hospital CPAP can reduce mortality and intubation rates, but cost-effectiveness is uncertain and the value of further randomised evaluation depends on the incidence of suitable patients. A feasibility study is required to determine if a large pragmatic trial of clinical effectiveness and cost-effectiveness is appropriate.

STUDY REGISTRATION

The study is registered as PROSPERO CRD42012002933.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Effectiveness and safety of a prehospital program of continuous positive airway pressure (CPAP) in an urban setting

BACKGROUND

Continuous positive airway pressure (CPAP) is commonly used in the treatment of acute cardiogenic pulmonary edema (ACPE) and acute exacerbations of chronic obstructive pulmonary disease (AECOPD). In-hospital evidence is robust: CPAP has been shown to improve respiratory status and to reduce intubation rates. There is less evidence on prehospital CPAP, although the emergency medical services (EMS) adoption of this modality is increasing. The objectives of this study were to 1) measure the effectiveness of prehospital CPAP on morbidity, mortality, and transport times; and 2) audit the selection of patients by medics for appropriateness and safety.

METHODS

We conducted a before-and-after study from August 1 to October 31 in 2010 and 2011, before and after the implementation of prehospital CPAP in a city of one million people with large rural areas. Medics were trained to apply CPAP to patients with respiratory distress and a presumed diagnosis of ACPE or AECOPD. Charts were selected using the search criteria of the chief complaint of shortness of breath, emergent transport to hospital, and any patients receiving CPAP in the field. Data extracted from ambulance call reports and hospital records were analysed with appropriate univariate statistics.

RESULTS

A total of 373 patients enrolled (186 pre-non-invasive ventilation [NIV] and 187 post-NIV), mean age 71.5 years, female 51.4%, and final diagnoses of ACPE 18.9%, AECOPD 21.9%. In the post group of 84 patients meeting NIV criteria, 41.6% received NIV; and of 102 patients not meeting the criteria, 5.2% received NIV. There were 12 minor adverse events in 36 applications (33.3%) as per protocol. Comparing post versus pre, there were higher rates of emergency department (ED) NIV (20.0% v. 13.4%, p<0.0001) and higher overall mortality (18.8% v. 14.9%, p<0.0001). There were no differences in ED intubation (2.1% v. 2.3%, p<0.001) and length of stay (6.8 v. 8.7 days, p=0.24).

CONCLUSION

Despite the robust in-hospital data supporting its use, we could not find benefit from CPAP in our prehospital setting with respect to morbidity, mortality, and length of stay. EMS must exercise caution in making the decision to invest in the equipment and training required to implement prehospital CPAP.

The impact of prehospital continuous positive airway pressure on the rate of intubation and mortality from acute out-of-hospital respiratory emergencies

BACKGROUND

Previous studies have demonstrated decreased rates of intubation and mortality with prehospital use of continuous positive airway pressure (CPAP). We sought to validate these findings in a larger observational study.

METHODS

We conducted a before and after observational study of consecutive patients transported by emergency medical services (EMS) during the 12 months before and the 12 months following implementation of a prehospital CPAP protocol for acute respiratory distress. Included were all patients transported by EMS meeting preestablished criteria indicative of acute respiratory distress and CPAP use (patient's problem specified as cardiac, respiratory distress, respiratory disease, or congestive heart failure [CHF]; age ≥ 12 years; chest sounds documented as wheezes or rales; Glascow Coma Scale [GCS] ≥ 11; respiratory rate ≥ 24 breaths per minute; systolic blood pressure ≥ 90 mmHg; and oxygen saturation < 90%). Data were abstracted from ambulance call reports (ACRs) and hospital records. All cases in which "do not resuscitate" (DNR) was documented on the patient chart or ACR or whose in-hospital outcome (death or discharge) was unknown were excluded.

RESULTS

In all, 442 patients met the above criteria. The mean (SD) age was 73.0 (13.9) years, and 51.5% were women. In-hospital mortality rates did not differ for these patients: 17/228 (7.5%) in the before group and 17/214 (7.9%) in the after group (p = 0.85). In-hospital intubation rates were similar for both groups (12.7 vs. 14.5%, p = 0.59). An analysis of the subgroup that had a hospital diagnosis of chronic obstructive pulmonary disease (COPD), CHF, or pulmonary edema (n = 273) showed mortality was somewhat lower in the before group (3/138, 2.2%) than in the after group (8/135, 5.9%) (p = 0.13). In-hospital intubation rates were also similar for both groups in this subgroup analysis (11.6 vs. 9.6%, p = 0.61).

CONCLUSION

In contrast to previous studies, we were unable to demonstrate a decrease in intubation or mortality related to the use of prehospital CPAP. Our findings may be specific to our EMS system but suggest that further large-scale, randomized, controlled trials may be warranted to firmly establish the benefit of prehospital CPAP.

Prehospital continuous positive airway pressure for acute respiratory failure: a systematic review and meta-analysis

INTRODUCTION

Acute respiratory failure (ARF) is a common problem encountered by emergency medical services and is associated with significant morbidity, mortality, and health care costs. Continuous positive airway pressure (CPAP) is an integral part of the hospital treatment of acute ARF, predominantly because of congestive heart failure. Intuitively, better patient outcomes may be achieved when CPAP is applied early in the prehospital setting, but there are few outcome studies to validate its use in this setting.

OBJECTIVE

This systematic review and meta-analysis aimed to examine the effectiveness of CPAP in the prehospital setting for patients with ARF.

METHODS

A literature review of bibliographic databases and secondary sources was conducted and potential papers were assessed by two independent reviewers. Included studies were those that compared CPAP therapy (and usual care) with no CPAP for ARF in the prehospital setting. Studies of other methods of noninvasive ventilation were not included. Methodologic quality was assessed using guidelines from the Cochrane Collaboration. Outcomes included the number of intubations, mortality, physiologic parameters, and dyspnea score. Forrest plots were constructed to estimate the pooled effect of CPAP on outcomes.

RESULTS

Five studies (1,002 patients) met the selection criteria--three randomized controlled trials (RCTs), a nonrandomized comparative study, and a retrospective comparative study using chart review. 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 (odds ratio [OR] 0.31; 95% confidence interval [CI] 0.19-0.51) and lower mortality (OR 0.41; 95% CI 0.19-0.87) in the CPAP group.

CONCLUSION

The studies included in this review showed a reduction in the number of intubations and mortality in patients with ARF who received CPAP in the prehospital setting. The results may not be applicable to other health care contexts because of the inherent differences in the organization and staffing of the EMS systems. Information from large RCTs on the efficacy of CPAP initiated early in the prehospital setting is critical to establishing the evidence base underpinning this therapy before ambulance services incorporate CPAP as routine clinical practice.

When Pressure is Positive: A Literature Review of the Prehospital Use of Continuous Positive Airway Pressure

Background

Heart failure poses a significant burden of disease, resulting in 2,658 Australian deaths in 2008, and listed as an associated cause of death in a further 14,466 cases. Common in the hospital setting, continuous positive airway pressure (CPAP) therapy is a non-invasive ventilation technique used to prevent airway collapse and manage acute pulmonary edema (APO). In the hospital setting, CPAP has been known to decrease the need for endotracheal intubation in patients with APO. Therefore the objective of this literature review was to identify the effectiveness of CPAP therapy in the prehospital environment.

Methods

A review of selected electronic medical databases (Cochrane, Medline, EMBASE, and CINAHL) was conducted from their commencement date through the end of May 2012. Inclusion criterion was any study type reporting the use of CPAP therapy in the prehospital environment, specifically in the treatment of heart failure and acute pulmonary edema. References of relevant articles were also reviewed.

Results

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. Continuous positive airway pressure therapy was also shown to improve patient vital signs during prehospital transport and reduce myocardial damage.

Discussion

The studies conducted of prehospital use of CPAP to manage APO have all demonstrated improvement in patient outcomes in the short term.

Conclusion

Available evidence suggests that the use of CPAP therapy in the prehospital environment may be beneficial to patients with acute pulmonary edema as it can potentially decrease the need for endotracheal intubation, improve vital signs during transport to hospital, and improve short-term mortality.

WilliamsB, BoyleM, RobertsonN, GiddingsC. When pressure is positive: a literature review of the prehospital use of continuous positive airway pressure. Prehosp Disaster Med.2013;28(1):1-10.

Noninvasive positive pressure ventilation: resource document for the National Association of EMS Physicians position statement

The National Association of EMS Physicians (NAEMSP) believes that noninvasive positive pressure ventilation (NIPPV) is an important treatment modality for the prehospital management of acute dyspnea. This document serves as a resource to the NAEMSP position on prehospital NIPPV.

Prehospital noninvasive ventilation can help in management of patients with limitations of life-sustaining treatments

OBJECTIVE

To evaluate the possible place of noninvasive positive pressure ventilation (NPPV) as a reversible and adjustable option offering the possibility of sustaining life until the hospital stay for patients with advanced life-support limitations and life-threatening respiratory distress in the prehospital setting.

METHODS

Patients managed by a physician-staffed Emergency Medical Service unit were retrospectively included if they met the three inclusion criteria: a respiratory failure with oxygen saturation (pulse oximetry) less than 90% (or respiratory exhaustion) under oxygen 15 l/min and a do-not-intubate discussion (according to the physician on-scene) and impossibility of conducting the discussion of withholding advanced life support on-scene.

RESULTS

Twelve patients were included. NPPV was a continuous positive airway pressure for eight patients and a bilevel positive airway pressure given by a ventilator for four patients. All the patients improved from respiratory point of view; respiratory rate decreased from 34 + or - 13 to 27 + or - 10 (P = 0.009) and pulse oximetry increased from 86 + or - 5 to 94 + or - 3% (P<0.01). NPPV was stopped in one case because of discomfort and worsening of consciousness, despite improved respiratory status.

CONCLUSION

This pilot series is promising and suggests that it could be a good option in case of limitations of life-sustaining treatments in the prehospital setting. A large controlled multicenter study, evaluating the use of NPPV in this context, would be very valuable.