Kopra Jukka, Litonius Erik, Pekkarinen Pirkka T, Laitinen Merja, Heinonen Juho A, Fontanelli Luca, Skrifvars Markus B
Department of Emergency Care and Services, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
Division of Anaesthesiology, Department of Anaesthesiology, Intensive Care and Pain Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
Intensive Care Med Exp. 2024 Apr 12;12(1):36. doi: 10.1186/s40635-024-00620-z.
In refractory out-of-hospital cardiac arrest, the patient is commonly transported to hospital with mechanical continuous chest compressions (CCC). Limited data are available on the optimal ventilation strategy. Accordingly, we compared arterial oxygenation and haemodynamics during manual asynchronous continuous ventilation and compressions with a 30:2 compression-to-ventilation ratio together with the use of 10 cmHO positive end-expiratory pressure (PEEP).
Intubated and anaesthetized landrace pigs with electrically induced ventricular fibrillation were left untreated for 5 min (n = 31, weight ca. 55 kg), after which they were randomized to either the CCC group or the 30:2 group with the the LUCAS® 2 piston device and bag-valve ventilation with 100% oxygen targeting a tidal volume of 8 ml/kg with a PEEP of 10 cmHO for 35 min. Arterial blood samples were analysed every 5 min, vital signs, near-infrared spectroscopy and electrical impedance tomography (EIT) were measured continuously, and post-mortem CT scans of the lungs were obtained.
The arterial blood values (median + interquartile range) at the 30-min time point were as follows: PaO: 180 (86-302) mmHg for the 30:2 group; 70 (49-358) mmHg for the CCC group; PaCO: 41 (29-53) mmHg for the 30:2 group; 44 (21-67) mmHg for the CCC group; and lactate: 12.8 (10.4-15.5) mmol/l for the 30:2 group; 14.7 (11.8-16.1) mmol/l for the CCC group. The differences were not statistically significant. In linear mixed models, there were no significant differences between the groups. The mean arterial pressures from the femoral artery, end-tidal CO, distributions of ventilation from EIT and mean aeration of lung tissue in post-mortem CTs were similar between the groups. Eight pneumothoraces occurred in the CCC group and 2 in the 30:2 group, a statistically significant difference (p = 0.04).
The 30:2 and CCC protocols with a PEEP of 10 cmHO resulted in similar gas exchange and vital sign outcomes in an experimental model of prolonged cardiac arrest with mechanical compressions, but the CCC protocol resulted in more post-mortem pneumothoraces.
在难治性院外心脏骤停中，患者通常在机械持续胸外按压（CCC）下被转运至医院。关于最佳通气策略的可用数据有限。因此，我们比较了在采用30:2的按压与通气比进行手动非同步持续通气和按压，并使用10cmH₂O呼气末正压（PEEP）时的动脉氧合和血流动力学情况。
将经气管插管并麻醉的长白猪电诱导室颤后不进行处理5分钟（n = 31，体重约55kg），之后将它们随机分为CCC组或30:2组，分别使用LUCAS® 2活塞装置和球囊面罩以100%氧气进行通气，目标潮气量为8ml/kg，PEEP为10cmH₂O，持续35分钟。每5分钟分析一次动脉血样本，持续测量生命体征、近红外光谱和电阻抗断层扫描（EIT），并在死后进行肺部CT扫描。
30分钟时间点的动脉血值（中位数+四分位间距）如下：30:2组的动脉血氧分压（PaO₂）为180（86 - 302）mmHg；CCC组为70（49 - 358）mmHg；30:2组的动脉血二氧化碳分压（PaCO₂）为41（29 - 53）mmHg；CCC组为44（21 - 67）mmHg；30:2组的乳酸为12.8（10.4 - 15.5）mmol/L；CCC组为14.7（11.8 - 16.1）mmol/L。差异无统计学意义。在线性混合模型中，两组之间无显著差异。两组之间股动脉平均动脉压、呼气末二氧化碳分压、EIT通气分布以及死后CT中肺组织平均通气情况相似。CCC组发生8例气胸，30:2组发生2例，差异有统计学意义（p = 0.04）。
在机械按压的长时间心脏骤停实验模型中，采用10cmH₂O PEEP的30:2方案和CCC方案导致相似的气体交换和生命体征结果，但CCC方案导致更多的死后气胸。
