Kaufmann Thomas, Castela Forte José, Hiemstra Bart, Wiering Marco A, Grzegorczyk Marco, Epema Anne H, van der Horst Iwan C C
Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands.
Department of Critical Care, University Medical Center Groningen, University of Groningen, Groningen, Netherlands.
JMIR Med Inform. 2019 Oct 30;7(4):e15358. doi: 10.2196/15358.
Hemodynamic assessment of critically ill patients is a challenging endeavor, and advanced monitoring techniques are often required to guide treatment choices. Given the technical complexity and occasional unavailability of these techniques, estimation of cardiac function based on clinical examination is valuable for critical care physicians to diagnose circulatory shock. Yet, the lack of knowledge on how to best conduct and teach the clinical examination to estimate cardiac function has reduced its accuracy to almost that of "flipping a coin."
The aim of this study was to investigate the decision-making process underlying estimates of cardiac function of patients acutely admitted to the intensive care unit (ICU) based on current standardized clinical examination using Bayesian methods.
Patient data were collected as part of the Simple Intensive Care Studies-I (SICS-I) prospective cohort study. All adult patients consecutively admitted to the ICU with an expected stay longer than 24 hours were included, for whom clinical examination was conducted and cardiac function was estimated. Using these data, first, the probabilistic dependencies between the examiners' estimates and the set of clinically measured variables upon which these rely were analyzed using a Bayesian network. Second, the accuracy of cardiac function estimates was assessed by comparison to the cardiac index values measured by critical care ultrasonography.
A total of 1075 patients were included, of which 783 patients had validated cardiac index measurements. A Bayesian network analysis identified two clinical variables upon which cardiac function estimate is conditionally dependent, namely, noradrenaline administration and presence of delayed capillary refill time or mottling. When the patient received noradrenaline, the probability of cardiac function being estimated as reasonable or good P(E) was lower, irrespective of whether the patient was mechanically ventilated (P[E|ventilation, noradrenaline]=0.63, P[E|ventilation, no noradrenaline]=0.91, P[E|no ventilation, noradrenaline]=0.67, P[E|no ventilation, no noradrenaline]=0.93). The same trend was found for capillary refill time or mottling. Sensitivity of estimating a low cardiac index was 26% and 39% and specificity was 83% and 74% for students and physicians, respectively. Positive and negative likelihood ratios were 1.53 (95% CI 1.19-1.97) and 0.87 (95% CI 0.80-0.95), respectively, overall.
The conditional dependencies between clinical variables and the cardiac function estimates resulted in a network consistent with known physiological relations. Conditional probability queries allow for multiple clinical scenarios to be recreated, which provide insight into the possible thought process underlying the examiners' cardiac function estimates. This information can help develop interactive digital training tools for students and physicians and contribute toward the goal of further improving the diagnostic accuracy of clinical examination in ICU patients.
ClinicalTrials.gov NCT02912624; https://clinicaltrials.gov/ct2/show/NCT02912624.
对危重症患者进行血流动力学评估是一项具有挑战性的工作，通常需要先进的监测技术来指导治疗决策。鉴于这些技术的技术复杂性以及偶尔无法使用的情况，基于临床检查来评估心功能对于重症监护医生诊断循环性休克很有价值。然而，对于如何最好地进行和教授临床检查以评估心功能缺乏了解，这使得其准确性几乎降低到了“抛硬币”的水平。
本研究旨在使用贝叶斯方法，基于当前标准化临床检查，调查重症监护病房（ICU）急性收治患者心功能评估背后的决策过程。
作为简单重症监护研究-I（SICS-I）前瞻性队列研究的一部分收集患者数据。纳入所有连续入住ICU且预期住院时间超过24小时的成年患者，对其进行临床检查并评估心功能。利用这些数据，首先，使用贝叶斯网络分析检查者评估与这些评估所依赖的一组临床测量变量之间的概率依赖性。其次，通过与重症监护超声测量的心脏指数值进行比较，评估心功能评估的准确性。
共纳入1075例患者，其中783例患者有经过验证的心脏指数测量值。贝叶斯网络分析确定了心功能评估有条件依赖的两个临床变量，即去甲肾上腺素的使用以及存在毛细血管再充盈时间延迟或皮肤花斑。当患者接受去甲肾上腺素治疗时，心功能被评估为正常或良好的概率P（E）较低，无论患者是否接受机械通气（P[E|通气，去甲肾上腺素]=0.63，P[E|通气，未用去甲肾上腺素]=0.91，P[E|未通气，去甲肾上腺素]=0.67，P[E|未通气，未用去甲肾上腺素]=0.93）。毛细血管再充盈时间或皮肤花斑也呈现相同趋势。学生和医生估计低心脏指数的敏感性分别为26%和39%，特异性分别为�3%和74%。总体而言，阳性和阴性似然比分别为1.53（95%CI 1.19-1.97）和0.87（95%CI 0.80-0.95）。
临床变量与心功能评估之间的条件依赖性导致了一个与已知生理关系一致的网络。条件概率查询允许重现多种临床场景，这有助于深入了解检查者心功能评估背后可能的思维过程。这些信息有助于为学生和医生开发交互式数字培训工具，并有助于实现进一步提高ICU患者临床检查诊断准确性的目标。
ClinicalTrials.gov NCT02912624；https://clinicaltrials.gov/ct2/show/NCT02912624
