Patient Safety Tip of the Week

November 11, 2014

Early Detection of Clinical Deterioration



In our July 15, 2014 Patient Safety Tip of the Week “Barriers to Success of Early Warning Systems” we again lamented the fact that early warning systems (EWS) to detect clinical deterioration of patients earlier have yet largely failed to live up to their promise. While the logic behind such scoring systems seems well-founded there has been a paucity of high-level evidence that such systems lead to substantial improvement in patient outcomes. Because of that and other factors, hospitals in the US have been very reluctant to adopt early warning scores into routine practice even as hospitals in the UK have been mandated to adopt such systems.


In that column we discussed an excellent study in the nursing literature (Watson 2014) that provided great insight into the barriers that impact implementation of an early warning system. Some of those barriers included:

1)      Delays in charting vital signs

2)      Poor consistency between charted vital signs and those used in the early warning systems (EWS)

3)      Multi-tasking by RN’s

4)      Recording vital signs first on paper, later entering into the computer

5)      Lack of computer availability or functionality

6)      Excess log-on times

7)      Preference for not charting in front of patient/family

8)      Lack of incorporating the RN’s impression of the patient status into the EWS

9)      General perception by RN’s that the EWS was no better at predicting deterioration than their own clinical impression


Watson and colleagues suggested changes to the physical environment and improved technology interfaces to support real-time data entry as ways to improve usefulness of the EWS:

1)      Bedside computer access or use of smartphones or tablets for documentation

2)      Have EMR’s automatically populate VS into the early warning score tool

3)      Re-examination of RN and non-RN tasks, perhaps returning VS assessment to RN’s so that data collection and documentation would be integrated

4)      Add RN concerns or family concerns to the criteria for the score


Now a new study that included many of those recommended practices into an EWS implementation has documented substantial improvement in mortality (Schmidt 2014). They implemented at two general hospitals in England an electronic physiological surveillance system (EPSS) which uses wireless handheld computing devices to replace a paper-based vital sign charting and clinical escalation system. After implementation of the system crude mortality for 56 diagnostic groups fell from 7.75% to 6.42% in one hospital and from 7.57% to 6.15% at the second hospital. They conclude that using technology specifically designed to improve the accuracy, reliability and availability of patients’ vital signs and early warning scores allows early recognition of and response to patient deterioration, resulting in improved mortality rates


In our February 22, 2011 Patient Safety Tip of the Week “Rethinking Alarms” we highlighted a paper by Lynn and Curry (Lynn 2011) that described 3 patterns of unexpected in-hospital deaths and discussed the problems with threshold-based alarms (almost all currently used alarm systems use threshold-based principles) in detecting early deterioration. Indeed, they posit that threshold-based alarms themselves often cause us to miss signs of early deterioration and make a case for implementation of “smart” alarms that integrate clinical data from multiple sources. The core concept of early warning systems, of course, is that using multiple factors should facilitate identification of clinical deterioration rather than just using a single factor.


In a very thoughtful commentary on the Schmidt study, David Bates and Eyal Zimlichman (Bates 2014) note the confluence of four major trends that should help overcome the barriers noted above. They note that the near-universal use of electronic medical records, better physiological sensors, background analytics, and mobile technology should facilitate earlier detection of clinical deterioration. They note that the Schmidt study still relied on intermittent vital sign measurement rather than using more continuous physiological measurements. So the potential to further improve this system is even greater. They do, however, note that the danger of alert fatigue might raise its ugly head and recommend caution and the need to address the false positive issue. They also acknowledge the importance of recognizing sociotechnical factors that might undermine such systems.


Hospitals have more and more adopted use of “middleware” and alerts delivered via mobile technologies to direct conditions needing attention to the healthcare workers who should provide that attention. That obviously is the wave of the future. It minimizes the “noise” of alerts and alarms going to everybody and gets them to the staff accountable for responses. But even then issues may arise. In our February 4, 2014 Patient Safety Tip of the Week “But What If the Battery Runs Low?” we noted a scenario where a patient event triggers an alarm that is sent to the primary nurse expected to respond but the battery in her cell phone has failed and she never receives the alert. Fortunately, the escalation procedure built into your system sends the alert to a secondary nurse who responds to the patient and no harm comes to the patient. Technological advances solve multiple problems but may introduce new potential problems as well.


In a related issue, early warning systems (EWS), of course, are intimately tied to rapid response teams (RRT’s) and rapid response systems (RRS’s). Like the evidence base for EWS, the evidence base for the success of RRT’s and RRS’s in improving patient outcomes has been mixed at best. The Medical Journal of Australia has just indicated it will be doing a series of articles exploring how RRS’s have changed approaches to patient safety, influenced end-of-life care, and the changing nature of cardiopulmonary arrest teams (Hillman 2014). One issue that has always popped up regarding both RRT’s and cardiopulmonary arrest teams is whether adverse events occur in other locations when team members have to abandon those locations to respond to the emergencies elsewhere. A new study answers that question (Concord MET Study 2014). The bad news is that disruptions of normal care routines and inconvenience to staff do occur in such situations. The good news is that it is very rare for adverse events or patient harm to come about because of those events.


Hopefully the new work by Schmidt and colleagues will rekindle interest in both early warning systems (EWS) and rapid response systems (RRS). As we have mentioned in several of our own columns on rapid response teams, the problem is not with the response teams. Rather it is with our poor recognition of early clinical deterioration.



Some of our other columns on MEWS or recognition of clinical deterioration:




Our other columns on rapid response teams:








Watson A, Skipper C, Steury R, et al. Inpatient Nursing Care and Early Warning Scores: A Workflow Mismatch. J Nurs Care Qual 2014; 29(3): 215-222



Schmidt PE, Meredith P, Prytherch DR, et al. Impact of introducing an electronic physiological surveillance system on hospital mortality. BMJ Qual Saf 2014; Published Online First: 23 September 2014



Lynn LA, Curry JP. Patterns of unexpected in-hospital deaths: a root cause analysis. Patient Safety in Surgery 2011, 5:3 (11 February 2011)



Bates DW, Zimlichman E. Finding patients before they crash: the next major opportunity to improve patient safety. BMJ Qual Saf 2014; Published Online First: 23 September 201



Hillman KM, Chen J, Jones D. Rapid response systems. Med J Aust 2014; 201 (9): 519-521



The Concord Medical Emergency Team (MET) Incidents Study Investigators. Incidents resulting from staff leaving normal duties to attend medical emergency team calls. Med J Australia 2014; 201: 528-531






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