Machbarkeitsstudie zum Einsatz des Vygon Boussignac CPAP im Rettungsdienst

Non-invasive ventilation (NIV) is a standard in-house treatment option for acute respiratory failure in emergency rooms and intensive care situations. With NIV, the patient's spontaneous breathing is supported through the application of external pressure, while the patient is usually conscious. Continuous positive airway pressure (CPAP) is one of the forms of NIV, where a constant stream of compressed air or oxygen is delivered to the patient's airways via a tube and tight fitting facial mask. A major advantage of NIV is prevention of anaesthesia and endotracheal intubation which has specific associated complications, especially in prehospital setting. Earlier studies were already able to demonstrate the benefits of NIV for the patients, especially if treatment is commenced early. It has also already been proven that CPAP can be used successfully in a prehospital setting, even by paramedical staff. Nevertheless, the treatment still has not seen widespread use in the German emergency medical service. It seems plausible that high costs and space requirements for modern emergency respirators are the main reasons for situation. In Giessen and Marburg-Biedenkopf, two counties in Hessen in central Germany, the Flow-CPAP System ‘Vygon Boussignac CPAP' is part of the equipment on all emergency physician chase cars as of 2006. Use of CPAP on patients with acute respiratory failure is primarily decided by the emergency physician. Though physicians were instructed, during introductions of the system, to use it on all patients with acute cardiogenic pulmonary edema and oxygen saturation (SpO2) below 90% if no contraindications were present. Until October 2009 207 preclinical treatments with Flow-CPAP had been recorded in an online database. The primary objective of this study was to show feasibility of the preclinical use of Vygon Boussignac CPAP. Therefore a five-point scale ranging from zero (therapy attempt aborted) to four (best efficiency and safety) was created. Grade zero and one (SpO2 improved by no more than 10%, inefficient) were summarised as ‘not feasible', while grades two, three and four meant ‘feasible'. The graduation was based on the decision to abort or continue therapy, change in SpO2 and state of consciousnes recorded using the Glasgow Coma Scale (GCS), heart rate, breathing rate and systolic blood pressure under continued therapy. Secondary endpoints were complications and undesired changes under preclinical CPAP treatment. Failed therapy attempts were also investigated for reasons leading to the abort. Each recorded parameter was also analysed in its progression during treatment. Feasibility was defined as >50% of therapy attempts in grades two, three and four. Results showed 70.1% within this range, so the therapy was confirmed to be feasible. In detail 11.7% were rated grade zero (therapy aborted), 18.3% grade one (no increase of SpO2 >10%), 13.7% grade two, 37.1% grade three and 16,8% grade four. An additional 2.5% of all therapy attempts showed to be feasible, but could not be classified further due to incomplete recording of data. Complication rate in feasible therapy attempts was only at 8.3%, whereby the reason for undesired changes may be attributed more likely to medication used i.e. analgosedatives, than the use of CPAP therapy itself. Therapy with Vygon Boussignac CPAP showed to be feasible and relatively safe in preclinical conditions. Benefit of treatment showed itself, among other things, in the development of SpO2. In 162 of the 163 patients with complete documentation an increase of up to 45% and 14% median was recorded. A very significant reduction in heartrate, breathingrate and systolic blood pressure during CPAP treatment was also noted. GCS scoring also showed a marked improvement. Though it has to be noted, that most patients had the highest possible scoring already pre-treatment, therefore recorded changes were infrequent. Randomized controlled multicenter studies are still to come to prove or disprove superiority of preclinical therapy with CPAP in patients with acute respiratory failure vs. the standard treatment with oxygen insufflation only or immediate endotracheal intubation. Also, long-term effects of both therapy options and the occurrence of complications in comparison are possible targets of future studies.