Prevalence and sensitivity of MET-criteria in a Scandinavian University Hospital

doi:10.1016/j.resuscitation.2005.11.011

Resuscitation

Volume 70, Issue 1, July 2006, Pages 66-73

https://doi.org/10.1016/j.resuscitation.2005.11.011 Get rights and content

Summary

Objective

To make a preliminary estimation of the workload for a medical emergency team (MET) in a Scandinavian University Hospital by recording prevalent physiological data on all adult patients and to see if the patients with deviating physiology (i.e. fulfilling the study criteria, in essence a set of simplified MET-criteria) had an elevated mortality. We also tested sensitivity and specificity by altering the cut-off levels of the calling criteria.

Design

Cross sectional prevalence study.

Setting

University hospital in the capital of Sweden.

Patients

Adult patients treated in the general wards of the hospital. Patients from psychiatric wards and intensive care units were excluded from the study.

Interventions

None.

Measurements and main results

4.5% of the scored patients fulfilled the study criteria. These patients had a 30-day mortality of 25% (confidence interval 12.7–41.2) as compared to 3.5% (2.4–5) for the patients not fulfilling the study criteria.

Extended criteria revealed 18 deaths within 30 days, 8 more deaths than the original study criteria. However, 123 patients – equalling 13.8% of the cohort (CI 11.6–16.2) – fulfilled these criteria as compared to the 40 patients fulfilling the original study criteria. Thus, the 30-day mortality of the patients with positive extended criteria totalled 14.6% (CI 8.9–22.1).

Restricted criteria showed a mere 20 patients (2.2%; CI 1.4–3.5) and only 4 deaths, making 30-day mortality 20% (CI 5.7–43.7); thus, sensitivity was actually lower using restricted criteria.

Conclusions

Even these modified – and simplified – MET-criteria proved to be able to single out patients with elevated mortality as compared to the rest of the hospital population. Extending the criteria significantly lowered sensitivity and would extend the MET-workload enormously. Restricting the criteria led to missed mortalities where intervention could be beneficial. The results suggest that a routine use of simple physiological tests can be of help in the identification of patients at risk.

Introduction

There is a trend towards shortened hospital length of stay in Sweden.¹ At the same time an aging population is offered very advanced care. This has resulted in larger numbers of older patients with a higher illness severity in the general wards of the hospital.

Studies have shown that adverse outcomes (AOs) are common among hospitalised patients2, 3 and antecedents to hospital deaths have been described in detail by Hillman et al.4, 5 and Kause et al.⁶ Whilst survival to hospital discharge in patients with in-hospital cardiac arrests has remained stable at between 14.7% and 16.7% for 30 years⁷ several studies of in-hospital cardiac arrests have shown that signs of clinical and physiological instability may often precede the arrest.8, 9, 10 Furthermore, other investigations have demonstrated suboptimal care of hospitalised patients before their admission to the intensive care unit (ICU), and the high mortality of these patients.11, 12, 13

The inference that lack of appropriate monitoring, skills and expertise in the general ward may lead to serious and potentially preventable complications such as cardiac arrest for the at-risk patient have prompted interventional programmes in several hospitals. The tools used in order to identify medical patients at risk of (catastrophic) deterioration differ between countries. In Australia the so called medical emergency teams (MET) use the criteria of the same name14, 15 whilst most centres in the UK prefer the Modified Early Warning Score (MEWS) as an adjunct to their critical care outreach service.16, 17 Recently a study from the University of Pittsburgh (USA) detailed data on their MET scoring system and its efficacy.¹⁸

During the planning phase before launching a medical emergency team in a Scandinavian University Hospital we needed to evaluate the criteria for MET-calls in our hospital setting. We wanted to estimate the workload of the team as measured by the prevalence of patients with deteriorating physiology. Our hypothesis was that the criteria for initiation of MET call would detect patients with increased risk of AOs and, consequently, higher mortality. Secondly, we attempted to test the accuracy of the criteria.

Section snippets

Hospital

The Karolinska University Hospital Solna is a teaching hospital in Stockholm, a city with a population of over 1 million. The hospital receives more than 74,000 acute admissions per year. It is the only hospital in the region with neurosurgical and cardio thoracic surgical units and serves as the trauma referral centre of the greater Stockholm area (1.8 × 10⁶ inhabitants). There is a specialized Department of General Oncology (Radiumhemmet), treating most of the malignant diseases in the area.

Results

Table 4 shows demographic data and mortality rate of the 1097 patients treated at the wards during the two study periods. The distribution of the cohort into the five separate categories mentioned in ‘Methods’ section is shown in Figure 1.

The patients fulfilling the study criteria had an almost 10-fold mortality rate during the first 30 days compared to the patients not fulfilling the criteria. This difference is statistically significant, with a p < 0.0001. However, the difference in mortality

Discussion

In this hospital-based cross sectional study, we observed that patients fulfilling the study criteria had a higher mortality compared to the hospital population that did not. The true workload of the future MET was difficult to gauge as we used only the prevalence of the patients fulfilling the modified criteria as a proxy for the workload. No measurements regarding time for interventions were done and, as discussed below, we could not include patients fulfilling the “worried”-criteria.

Conclusions

Even these modified – and simplified – MET-criteria proved to be able to single out patients with elevated mortality as compared to the rest of the hospital population. Extending the criteria significantly lowered sensitivity and would extend the MET-workload enormously. In contrast, restricting the criteria led to missed mortalities where one can assume that intervention could be beneficial. The results seem to suggest that routine use of simple physiological tests can help us identify

Financial disclosure/conflict of interest statement

This work has been supported by the Department of Anaesthesiology and Intensive Care at the Karolinska University Hospital Solna, Stockholm, Sweden.

No conflicts of interest for any of the authors exist.

Acknowledgements

The authors wish to thank Katarina Karlsson, Rolf Söderlund and Eva-Maria Wallin from the Central Intensive Care Unit and all the teachers and students from The Red Cross Nursing School for their help with this study.

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During the study period, 4522 patients were included in the final analysis. Cardiovascular and respiratory changes were more common causes of nighttime activation, whereas neurological and laboratory changes were more common during the daytime. The in-hospital mortality rate was 23.9% (1081/4522). Nighttime RRT calls were not associated with worse outcomes than daytime calls. However, a decrease in the number of calls was observed during nursing handover periods (7:00, 13:00 and 19:00). Two time periods were associated with increased adjusted odds for mortality: 12:00–13:00 (adjusted OR 2.277; 95% CI 1.392–3.725) and 19:00–20:00 (adjusted OR 1.873; CI 1.873; 95% 1.099–3.190).
We found that nighttime RRT calls were not associated with worse outcomes than daytime RRT calls. However, a decrease in the number of calls and higher mortality was observed during nursing handover periods.
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This was a retrospective observational study of adult patients admitted through the ED at Karolinska University Hospital 1 January to 31 October 2015.
The cohort included 25,646 ED admissions, frequency of DNACPR decisions was 11% during hospitalisation. Patients with DNACPR decisions were older, with an overall higher burden of chronic comorbidities, unstable triage scoring, hospital mortality and one-year mortality compared to those without. For patients with DNACPR decisions, 63% survived to discharge and one-year mortality was 77%. Age and comorbidities for patients with DNACPR decisions were similar regardless of hospital mortality, those who died showed signs of more severe acute illness on ED arrival. Change in CPR status during hospitalisation was 5% and upon subsequent admission 14%. For patients discharged with DNACPR decisions, reversal of DNACPR status upon subsequent admission was 32%, with uncertainty as to whether this reversal was active or a consequence of a lack of consideration.
For a mixed population of adults admitted through the ED, frequency of DNACPR decisions was 11%. Two-thirds of patients with DNACPR decisions were discharged, but one-year mortality was high. For patients discharged with DNACPR decisions, reversal of DNACPR status was substantial and this should merit further attention.
Non-invasive continuous haemodynamic monitoring and response to intervention in haemodynamically unstable patients during rapid response team review
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During rapid response team (RRT) management of haemodynamic instability (HI), continuous non-invasive haemodynamic monitoring may provide supplemental physiological information.
To continuously and non-invasively obtain the cardiac index (CI) and mean arterial pressure (MAP) in patients with HI at baseline and during RRT management using the ClearSight™ device.
We performed a prospective observational study in adult patients managed by the RRT for tachycardia or hypotension or both. We assessed changes from baseline in heart rate (HR), MAP, CI, stroke volume index (SVI) and systemic vascular resistance index (SVRI) (i) at 5-minutely intervals up to 20 min, and (ii) over the entire 20-min period. We analysed patients by RRT trigger (tachycardia/hypotension) and intervention (fluid bolus therapy [FBT]/ no FBT).
We successfully recorded the CI in 47 of 50 (94%) patients. RRT reviews triggered by hypotension rather than tachycardia had a lower baseline HR (−45.4 bpm, p = <0.0001), MAP (−16.1 mmHg, p = 0.0007) and CI (1.0 L/min/m², p = 0.0025). Compared to baseline, in the tachycardia group, there was a small increase in MAP overall and at the 15–20 min time-block from 83.2 mmHg to 87.1 mmHg (+3.9 mmHg, p = 0.0066) and 85.5 mmHg (+2.3 mmHg, p = 0.0061), respectively. In those who received FBT, there was a statistically significant increase in MAP overall and at the 15–20 min time-block compared to baseline, from 70.1 mmHg to 73.5 mmHg (+3.4 mmHg, p = 0.0036) and 74.3 mmHg (+4.2 mmHg, p = 0.0037), respectively. However, there were no statistically significant changes in mean HR, CI, SVI, or SVRI when comparing baseline to the entire 20-min period or 5-min time-blocks within any group.
Continuous non-invasive measurement of haemodynamics during RRT management for HI was possible for 20 min. Patients with hypotension rather than tachycardia had lower baseline HR, MAP and CI values. There was a statistically significant but small increase in MAP at the 15–20 min time-block and overall, for both the tachycardia and FBT groups.
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The NEWS can be a probable proxy for estimating physiological reserve capacity since high NEWS is associated to high change of death in case of an IHCA. This information can be used when discussing prognosis with patients and relatives. But even more importantly, it stresses the need for better preventive strategies in IHCAs.
- •
  Strengths include the complete information about the outcome, i.e. 30-day survival or not due to Swedish Personal Identification Numbers and registries.
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  Another strength is the collection of exposure data, NEWSs, was based on a strict a priori determined protocol, including only data documented in the medical record and therefore known to the staff before the IHCA.
- •
  Limitations include the use of only documented vital signs, i.e. those taken but not documented, as well as the fact that information on interventions performed but not documented in the medical file are missing.
- •
  A potential limitation is the lack of a control group with equally abnormal vital signs but no IHCA; such information would have answered the question how predictive the NEWS is for an IHCA but this is out of the scope of this study regardless.
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^☆: A Spanish translated version of the Summary of this article appears as Appendix in the online version at doi:10.1016/j.resuscitation.2005.11.011.

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Clinical paperPrevalence and sensitivity of MET-criteria in a Scandinavian University Hospital☆

Summary

Objective

Design

Setting

Patients

Interventions

Measurements and main results

Conclusions

Introduction

Section snippets

Hospital

Results

Discussion

Conclusions

Financial disclosure/conflict of interest statement

Acknowledgements

Resuscitation

Chest

Resuscitation

Resuscitation

In-patient diseases in Sweden 1987–2001

The National Board of Health and Welfare

Incidence of adverse events and negligence in hospitalized patients. Results of the Harvard Medical Practice Study I

N Engl J Med

The quality in Australian Health Care Study

Med J Aust

Duration of life-threatening antecedents prior to intensive care admission

Intensive Care Med

Antecedents to hospital deaths

Intern Med J

In-hospital cardiopulmonary resuscitation. Survival in 1 hospital and literature review

Medicine (Baltimore)

Recognising clinical instability in hospital patients before cardiac arrest or unplanned admission to intensive care. A pilot study in a tertiary-care hospital

Med J Aust

Developing strategies to prevent in-hospital cardiac arrest: analyzing responses of physicians and nurses in the hours before the event

Crit Care Med

Confidential inquiry into quality of care before admission to intensive care

BMJ

Clinical paper
Prevalence and sensitivity of MET-criteria in a Scandinavian University Hospital☆