Lynn Lawrence A, Curry J Paul
Department of Anesthesiology and Perioperative Care, Hoag Memorial Hospital Presbyterian, Newport Beach, CA 92658 USA.
Patient Saf Surg. 2011 Feb 11;5(1):3. doi: 10.1186/1754-9493-5-3.
Respiratory alarm monitoring and rapid response team alerts on hospital general floors are based on detection of simple numeric threshold breaches. Although some uncontrolled observation trials in select patient populations have been encouraging, randomized controlled trials suggest that this simplistic approach may not reduce the unexpected death rate in this complex environment. The purpose of this review is to examine the history and scientific basis for threshold alarms and to compare thresholds with the actual pathophysiologic patterns of evolving death which must be timely detected.
The Pubmed database was searched for articles relating to methods for triggering rapid response teams and respiratory alarms and these were contrasted with the fundamental timed pathophysiologic patterns of death which evolve due to sepsis, congestive heart failure, pulmonary embolism, hypoventilation, narcotic overdose, and sleep apnea.
In contrast to the simplicity of the numeric threshold breach method of generating alerts, the actual patterns of evolving death are complex and do not share common features until near death. On hospital general floors, unexpected clinical instability leading to death often progresses along three distinct patterns which can be designated as Types I, II and III. Type I is a pattern comprised of hyperventilation compensated respiratory failure typical of congestive heart failure and sepsis. Here, early hyperventilation and respiratory alkalosis can conceal the onset of instability. Type II is the pattern of classic CO2 narcosis. Type III occurs only during sleep and is a pattern of ventilation and SPO2 cycling caused by instability of ventilation and/or upper airway control followed by precipitous and fatal oxygen desaturation if arousal failure is induced by narcotics and/or sedation.
The traditional threshold breach method of detecting instability on hospital wards was not scientifically derived; explaining the failure of threshold based monitoring and rapid response team activation in randomized trials. Furthermore, the thresholds themselves are arbitrary and capricious. There are three common fundamental pathophysiologic patterns of unexpected hospital death. These patterns are too complex for early detection by any unifying numeric threshold. New methods and technologies which detect and identify the actual patterns of evolving death should be investigated.
医院普通病房的呼吸警报监测和快速反应团队警报是基于检测简单的数值阈值突破。尽管在特定患者群体中进行的一些非对照观察性试验令人鼓舞，但随机对照试验表明，这种简单的方法可能无法降低这种复杂环境中的意外死亡率。本综述的目的是研究阈值警报的历史和科学依据，并将阈值与必须及时检测到的不断演变的死亡实际病理生理模式进行比较。
在PubMed数据库中搜索与触发快速反应团队和呼吸警报的方法相关的文章，并将这些文章与因败血症、充血性心力衰竭、肺栓塞、通气不足、麻醉剂过量和睡眠呼吸暂停而演变的基本定时病理生理死亡模式进行对比。
与生成警报的数值阈值突破方法的简单性形成对比的是，不断演变的死亡实际模式很复杂，直到接近死亡时才具有共同特征。在医院普通病房，导致死亡的意外临床不稳定通常沿着三种不同的模式发展，可指定为I型、II型和III型。I型是由充血性心力衰竭和败血症典型的过度通气代偿性呼吸衰竭组成的模式。在这里，早期过度通气和呼吸性碱中毒可以掩盖不稳定的发作。II型是经典的二氧化碳麻醉模式。III型仅在睡眠期间发生，是由通气和/或上呼吸道控制不稳定引起的通气和血氧饱和度循环模式，如果麻醉剂和/或镇静导致唤醒失败，则随后会出现急剧且致命的氧饱和度下降。
医院病房中检测不稳定的传统阈值突破方法并非基于科学推导；这解释了在随机试验中基于阈值的监测和快速反应团队激活失败的原因。此外，阈值本身是任意且多变的。医院意外死亡有三种常见的基本病理生理模式。这些模式过于复杂，无法通过任何统一的数值阈值进行早期检测。应研究检测和识别不断演变的死亡实际模式的新方法和技术。
