Mechanical Ventilation During Resuscitation: How Manual Chest Compressions Affect a Ventilator's Function

Guidelines for resuscitation recommend positive-pressure ventilation with a fixed ventilation rate as provided by an automated transport ventilator during cardiopulmonary resuscitation (CPR) with a secured airway. We investigated the influence of manual chest compressions (CC) on the accuracy of ventilator presets and the quality of CC with intermittent positive-pressure ventilation (IPPV), bilevel ventilation (BiLevel), and the novel ventilation mode chest compression synchronized ventilation (CCSV) in a simulation model. Ninety paramedics performed continuous CC for 2 min on a modified advanced life support mannequin with a realistic lung model. IPPV, BiLevel, and CCSV were applied in a randomized order. CCSV is a novel type of pressure-controlled ventilation with short insufflations synchronized with CC, which are stopped before decompression begins. The ventilator presets (tolerance range) were IPPV Vt = 450 (400-500) ml, PEEP = 0 hPa, f = 10/min; BiLevel Pinsp = 19 (17.1-20.9) hPa, PEEP = 5 hPa, f = 10/min; CCSV Pinsp = 60 (54-66) hPa, PEEP = 0 hPa, Tinsp = 205 ms, f = CC rate. Preset values were compared with the measured results. Values were defined as correct within a tolerance range. Quality of CC was evaluated using ERC guidelines (depth > 50 mm, CC rate 100-120/min). Median (25th/75th percentiles) IPPV V (t) = 399 (386/411) ml, BiLevel Pinsp = 22.0 (19.7/25.6) hPa, and CCSV Pinsp = 55.2 (52.6/56.7) hPa. 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. CC depth: IPPV 56 (48/63) mm, BiLevel 57 (48/63) mm, CCSV 60 (52/67) mm; CC rate: IPPV 117 (105/124)/min, BiLevel 116 (107/123)/min, CCSV 117 (107/125)/min. When compared to IPPV and BiLevel, CCSV works best with preset values, without exceeding the upper pressure preset during simulated CPR. Quality of CC is not negatively affected by any of the ventilation patterns.