Einfluss der manuellen Thoraxkompression auf Beatmungsparameter der maschinellen Ventilation bei der kardiopulmonalen Reanimation im Simulationsmodell

The guidelines of the European Resuscitation Council (ERC) recommend positive- pressure ventilation with a tidal volume of 6–7 ml/kg body weight and a fixed ventilation rate of 10/min as provided by an automated transport ventilator during Cardiopulmonary Resuscitation (CPR) with a secured airway. Nevertheless, evidence for a particular ventilation pattern or a specific ventilation strategy is still limited. This dissertation adresses the influence of manual Chest Compressions (CC) on the accuracy of ventilator presets (tidal volume, Vt and inspiratory pressure, Pinsp) of the three ventilation patterns Intermittent Positive Pressure Ventilation (IPPV), BiLevel-Ventilation (BiLevel) and Chest Compression Synchronised Ventilation (CCSV) in a simulation model. Further information on the feasibility of the mentioned ventilation patterns during CPR should be collected and thus their significance assessed. After approval by the Ethics Committee of the Faculty of Medicine of the Philipps- University of Marburg (reference number: study 36/14), 90 paramedics performed continuous manual CC for two minutes on a modified Advanced Life Support (ALS)-mannequin with a realistic lung model. The three different ventilation patterns IPPV, BiLevel and CCSV were applied for 30 s each in a randomised order. CCSV is a novel, pressure-controlled ventilation mode, in which the insufflation is synchronised with the compression phase. This synchronisation is also dependent on a rapid increase of the airway pressure (25–375 mbar/s) above a predefined pressure level (0.9–3.7 mbar above Positive Endexpiratory Pressure, PEEP) following an expiratory phase of a specific duration (200–340 ms). The ventilator presets (tolerance range) were: IPPV Vt = 450 ml (400–500 ml), PEEP = 0 mbar, f = 10/min; BiLevel Pinsp = 19 mbar (17.1–20.9 mbar), PEEP = 5 mbar, f = 10/min; CCSV: Pinsp = 60 mbar (56–66 mbar), PEEP = 0 mbar, Tinsp = 205 ms, f = CC rate. Pressure-flow curves were recorded and the preset values were compared with the measured results. Values were defined as correct within tolerance range and analysed with Wilcoxon-Matched-Pairs-Test, results are presented below as median (25/75 % per- centiles). The tidal volume (Vt) during ventilation with IPPV was 399 ml (386/411 ml), the inspiration pressure (Pinsp) during ventilation with BiLevel was 22.0 mbar (19.7/25.6 mbar) and during ventilation with CCSV 55.2 mbar (52.6/56.7 mbar). Relative frequency of delivering correct ventilation parameters according to ventilation mode: IPPV = 40 % (0/100 %) vs. BiLevel = 20 % (0/100%), p = 0.37 and vs. CCSV = 71 % (50/83 %), p < 0.02. Pinsp was too high in BiLevel = 80 % (0/100 %) vs. CCSV = 0 % (0/0%), p < 0.001. This thesis shows that ventilation patterns during simulated CPR differ significantly regarding the accuracy of delivering preset ventilation parameters (Vt and Pinsp). CCSV complies best with preset values compared to IPPV and BiLevel ventilation without exceeding the upper pressure preset. During ventilation with IPPV measured tidal volumes did not reach ventilators volume presets. During ventilation with BiLevel measured inspiratory pressures exceeded tolerance range. This dissertation thus complements the limited data on ventilation parameters during CPR and demonstrates that CCSV might be most suitable for ventilation during cardiac arrest.