Background and importance 

No large randomised controlled trial has assessed the potential benefits on neurologic outcomes of prehospital sodium bicarbonate administration in patients with nontraumatic out-of-hospital cardiac arrest (OHCA).

Objective 

To obtain information of assistance in designing a randomised controlled trial of bicarbonate therapy after OHCA in specific patient subgroups.

Design 

We conducted two, separate, simultaneous, retrospective studies of two distinct, unlinked datasets.

Setting and participants 

One dataset was a French nationwide population-based registry (RéAC Registry, French dataset) and the other was a randomised controlled trial comparing continuous to interrupted chest compressions in North America (ROC-CCC trial, North-American dataset).

Intervention 

We investigated whether prehospital bicarbonate administration was associated with better neurologic outcomes.

Outcome measures and analyses 

The main outcome measure was the functional outcome at hospital discharge. To adjust for potential confounders, we conducted a nested propensity-score-matched analysis with inverse probability-of-treatment weighting.

Main results 

In the French dataset, of the 54 807 patients, 1234 (2.2%) received sodium bicarbonate and 450 were matched. After propensity-score matching, sodium bicarbonate was not associated with a higher likelihood of favourable functional outcomes on day 30 [adjusted odds ratio (aOR), 0.912; 95% confidence interval (95%CI), 0.501–1.655]. In the North-American dataset, of the 23 711 included patients, 4902 (20.6%) received sodium bicarbonate and 1238 were matched. After propensity-score matching, sodium bicarbonate was associated with a lower likelihood of favourable functional outcomes at hospital discharge (aOR, 0.45; 95% CI, 0.34–0.58).

Conclusion 

In patients with OHCA, prehospital sodium bicarbonate administration was not associated with neurologic outcomes in a French dataset and was associated with worse neurologic outcomes in a North-American dataset. Given the considerable variability in sodium bicarbonate use by different prehospital care systems and the potential resuscitation-time bias in the present study, a large randomised clinical trial targeting specific patient subgroups may be needed to determine whether sodium bicarbonate has a role in the prehospital management of prolonged OHCA.

中文翻译：

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碳酸氢钠对院外心脏骤停患者功能结果的影响：对法国和北美数据集的事后分析

背景和重要性 

没有大型随机对照试验评估了院前给予碳酸氢钠对非创伤性院外心脏骤停 (OHCA) 患者神经系统结局的潜在益处。

客观的 

获得帮助设计在特定患者亚组中进行 OHCA 后碳酸氢盐治疗的随机对照试验的信息。

设计 

我们对两个不同的、未链接的数据集进行了两项独立、同时的回顾性研究。

设置和参与者 

一个数据集是法国全国范围内的基于人群的登记处（RéAC Registry，法国数据集），另一个是比较北美连续胸外按压与间断胸外按压的随机对照试验（ROC-CCC 试验，北美数据集）。

干涉 

我们调查了院前碳酸氢盐给药是否与更好的神经系统结局相关。

结果测量和分析 

主要结局指标是出院时的功能结局。为了调整潜在的混杂因素，我们进行了嵌套的倾向得分匹配分析，采用逆治疗概率加权。

主要结果 

在法国数据集中，54807 名患者中，1234 名（2.2%）接受了碳酸氢钠治疗，450 名匹配。在倾向得分匹配后，碳酸氢钠与第 30 天获得良好功能结果的可能性更高无关[调整优势比 (aOR)，0.912；95% 置信区间 (95%CI), 0.501–1.655]。在北美数据集中，纳入的 23711 名患者中，4902 名（20.6%）接受了碳酸氢钠治疗，1238 名匹配。倾向评分匹配后，碳酸氢钠与出院时获得良好功能结果的可能性较低相关（aOR，0.45；95% CI，0.34-0.58）。

结论 

在 OHCA 患者中，院前碳酸氢钠给药与法国数据集中的神经系统结果无关，而在北美数据集中与更差的神经系统结果相关。鉴于不同院前护理系统使用碳酸氢钠的差异很大，以及本研究中潜在的复苏时间偏差，可能需要针对特定​​患者亚组进行大型随机临床试验，以确定碳酸氢钠是否在院前管理中发挥作用。 OHCA 延长。