Prehospital treatment with continuous positive airway pressure in patients with acute respiratory failure: a regional observational study

Abstract

BackgroundPatients with acute respiratory failure are at risk of deterioration during prehospital transport. Ventilatory support with continuous positive airway pressure (CPAP) can be initiated in the prehospital setting. The objective of the study is to evaluate adherence to treatment and effectiveness of CPAP as an addition to standard care.MethodsIn North Denmark Region, patients with acute respiratory failure, whom paramedics assessed as suffering from acute cardiopulmonary oedema, acute exacerbation of chronic obstructive pulmonary disease or asthma were treated with CPAP using 100 % O2 from 1 March 2014 to 3 May 2015. Adherence to treatment was evaluated by number of adverse events and discontinuation of treatment. Intensive care admissions and mortality were reported in this cohort. Effectiveness was evaluated by changes in peripheral oxygen saturation (SpO2) and respiratory rate during transport and compared to a historical control (non-CPAP) group treated with standard care only. Values were compared by hypothesis testing and linear modelling of SpO2 on arrival at scene and ΔSpO2 stratified according to treatment group.ResultsIn fourteen months, 171 patients were treated with CPAP (mean treatment time 35 ± 18 min). Adverse events were reported in 15 patients (9 %), hereof six discontinued CPAP due to hypotension, nausea or worsening dyspnoea. One serious adverse event was reported, a suspected pneumothorax treated adequately by an anaesthesiologist called from a mobile emergency care unit. Among CPAP patients, 45 (27 %) were admitted to an intensive care unit and 24 (14 %) died before hospital discharge. The non-CPAP group consisted of 739 patients. From arrival at scene to arrival at hospital, CPAP patients had a larger increase in SpO2 than non-CPAP patients (87 to 96 % versus 92 to 96 %, p < 0.01) and a larger decrease in respiratory rate (32 to 25 versus 28 to 24 breaths/min, p < 0.01). In a linear model, CPAP was superior to non-CPAP in patients with initial SpO2 ≤90 % (p < 0.05). One CPAP patient (0.6 %) and eight non-CPAP patients (1.1 %) were intubated in the prehospital setting.DiscussionThe study design reflects the daily prehospital working environment including long transport timesand paramedics educated in treating symptoms of acute respiratory failure, rather than treating one specific diagnosis. The study population was included consecutively and few patients were lost to follow-up. However, the study was too small to allow assessment of any effect of prehospital CPAP on mortality, nor could the effectiveness in specific disease conditions be examined.ConclusionsIn an emergency medical service including physician backup, adherence to CPAP treatment administered by paramedics was high and treatment was effective in patients with acute respiratory failure.

Association of Prehospital Oxygen Saturation to Inspired Oxygen Ratio With 1-, 2-, and 7-Day Mortality

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Characteristics and outcomes of patients with dyspnoea as the main symptom, assessed by prehospital emergency nurses- a retrospective observational study

“…This requires advanced knowledge from the PENs who is caring for patients with dyspnoea, as abnormal vital parameters may be a sign of a number of different serious conditions; both cardiogenic, pulmonary and other aetiologies of acute respiratory failure. This highlights the importance of early recognition of the patients condition and directed treatment already at an early stage by EMS, as it might be crucial for the final outcome [ 33 – 35 ]. It has previously been reported that acute ill patients (including those with dyspnoea) admitted thorough ED [ 36 ] with abnormal vital parameters, have an increased risk of death.…”

Pre-hospital continuous positive airway pressure after blast lung injury and hypovolaemic shock: a modelling study

“…The application of pre-hospital CPAP for the emergency treatment of acute respiratory failure (ARF) is increasingly used by emergency medical services. 1 In non-traumatic ARF, prehospital application CPAP via a tight-fitting mask reduces ventilatory frequency and the need for subsequent intubation. 2e4 Additionally, porcine data suggest the potential for decreased mortality, decreased pulmonary oedema, and increased arterial oxygen saturation after toxic lung injury when ambient-air CPAP is administered shortly after injury.…”