Background 

COBRA was developed as a decision rule to predict which patients visiting the emergency department (ED) following intentional drug overdose will not require intensive care unit (ICU) interventions. COBRA uses parameters from five vital systems (cardiac conduction, oxygenation, blood pressure, respiration, and awareness) that are readily available in the ED. COBRA recommends against ICU admission when all these parameters are normal.

Objective 

The primary aim of this study was to determine the negative predictive value (NPV) of COBRA in predicting ICU interventions. Secondary outcomes were the sensitivity, specificity and positive predictive value (PPV), and the observation time required for a reliable prediction.

Design 

Observational cohort study.

Settings and participants 

Patients with a reported intentional overdose with drugs having potential acute effects on neurological, circulatory or ventilatory function were included, and data necessary to complete the decision rule was collected. The attending physician in the ED made the actual admission decision, on the basis of clinical judgement. COBRA was measured 0, 3 and 6 h after arrival at the ED.

Outcome measures 

Need for ICU interventions (treatment of convulsion; defibrillation; mechanical or noninvasive ventilation; intravenous administration of vasopressive agents, antiarrhythmics, atropine, calcium, magnesium or sedation; continuous hemofiltration or administration of antagonist/antidote and fluid resuscitation).

Main results 

Of 230 new cases (144 unique patients), 59 were immediately referred to the psychiatric services and/or sent home by the attending physician, 27 went to a regular ward, and 144 were admitted to the ICU. Of these 144 cases, 40 required one or more ICU interventions. By the time the first parameters were collected, the NPV of COBRA was 95.6%. After 3 h of observation, NPV was 100%, while sensitivity, specificity and PPV were 100, 61.1 and 35.1%, respectively. None of these values improved by prolonging the observation time to 6 h.

Conclusion 

In patients with a reported intentional overdose with drugs having potential acute effects on neurological, circulatory or ventilatory function, the COBRA decision rule showed good performances in predicting the need for intensive care interventions, with a NPV of 100% after 3 h of observation.

中文翻译：

---

COBRA 的性能，一种预测故意药物过量需要重症监护干预的决策规则

背景 

COBRA 是作为一种决策规则开发的，用于预测哪些患者在故意用药过量后去急诊室 (ED) 不需要重症监护室 (ICU) 干预。COBRA 使用来自五个重要系统（心脏传导、氧合、血压、呼吸和意识）的参数，这些参数在 ED 中很容易获得。当所有这些参数都正常时，COBRA 建议不要入住 ICU。

客观的 

本研究的主要目的是确定 COBRA 在预测 ICU 干预中的阴性预测值 (NPV)。次要结果是敏感性、特异性和阳性预测值 (PPV)，以及可靠预测所需的观察时间。

设计 

观察性队列研究。

设置和参与者 

报告了故意过量服用对神经、循环或通气功能有潜在急性影响的药物的患者，并收集了完成决策规则所需的数据。急诊科的主治医师根据临床判断做出实际的入院决定。在到达急诊室后 0、3 和 6 小时测量 COBRA。

结果措施 

需要 ICU 干预（抽搐治疗；除颤；机械或无创通气；静脉内给予血管加压药、抗心律失常药、阿托品、钙、镁或镇静剂；持续血液滤过或给予拮抗剂/解毒剂和液体复苏）。

主要结果 

在 230 名新病例（144 名独特患者）中，59 人立即转诊至精神科和/或由主治医师送回家，27 人进入普通病房，144 人被送入 ICU。在这 144 例病例中，40 例需要一次或多次 ICU 干预。到收集第一个参数时，COBRA 的 NPV 为 95.6%。观察 3 h 后，NPV 为 100%，而敏感性、特异性和 PPV 分别为 100、61.1 和 35.1%。将观察时间延长至 6 小时后，这些值均未得到改善。

结论 

在报告故意过量服用对神经、循环或通气功能具有潜在急性影响的药物的患者中，COBRA 决策规则在预测需要重症监护干预方面表现出良好的性能，观察 3 小时后 NPV 为 100%。