Six year audit of cardiac arrests and medical emergency team calls in an Australian outer metropolitan teaching hospitalBMJ 2007; 335 doi: https://doi.org/10.1136/bmj.39385.534236.47 (Published 06 December 2007) Cite this as: BMJ 2007;335:1210
- Michael Buist, intensive care director 1,
- Julia Harrison, staff specialist1,
- Ellie Abaloz, nurse unit manager 1,
- Susan Van Dyke, quality manager
- Correspondence to: M Buist
- Accepted 10 October 2007
Problem In-hospital cardiac arrest often represents failure of optimal clinical care. The use of medical emergency teams to prevent such events is controversial. In-hospital cardiac arrests have been reduced in several single centre historical control studies, but the only randomised prospective study showed no such benefit. In our hospital an important problem was failure to call the medical emergency team or cardiac arrest team when, before in-hospital cardiac arrest, patients had fulfilled the criteria for calling the team.
Design Single centre, prospective audit of cardiac arrests and data on use of the medical emergency team during 2000 to 2005.
Setting 400 bed general outer suburban metropolitan teaching hospital.
Strategies for change Three initiatives in the hospital to improve use of the medical emergency team: orientation programme for first year doctors, professional development course for medical registrars, and the evolving role of liaison intensive care unit nurses.
Key measures for improvement Incidence of cardiac arrests.
Effects of the change Incidence of cardiac arrests decreased 24% per year, from 2.4/1000 admissions in 2000 to 0.66/1000 admissions in 2005.
Lessons learnt Medical emergency teams can be efficacious when supported with a multidisciplinary, multifaceted education system for clinical staff.
In our hospital, the occurrence of cardiac arrest often indicates delayed or suboptimal clinical management of the patient.1 The outcome from in-hospital cardiac arrest is universally poor,23456 and regardless of outcome the patient’s clinical experience is often catastrophic. Our hospital implemented a medical emergency team in 1996, and within three years the incidence of cardiac arrests (adjusted for case mix) dropped by 50%.7 Three other studies have since reported similar findings,8910 but they have been criticised because they used a historical control, before-after methodology.11 12
Recently in the MERIT study, a large randomised prospective study of medical emergency team implementation,13 a composite outcome of cardiac arrest, unexpected death, and unplanned admission to the intensive care unit was not significantly reduced (5.86 v 5.31, P=0.64). However, in both the intervention and control hospitals the overall calls for an emergency team increased(3.1 v 8.7 calls per 1000 admissions, P=0.0001). Both control and intervention hospitals had a reduction in cardiac arrests (2.08 v 1.47, P=0.003) and unexpected deaths (1.63 v 1.11,P=0.01). The MERIT authors listed several reasons to explain the findings: the intervention was ineffective; the medical emergency team was effective but was poorly implemented in the intervention hospitals; the study’s time frame of 12 months was too short for effective implementation; clinical cross contamination between the two groups; the study was underpowered; the study was impossible to blind; the study could not control for overall system-wide improvement; and in the control hospitals the cardiac arrest team often functioned as a de facto medical emergency team.
Despite the results of the MERIT study, more and more hospitals have set up medical emergency or rapid response teams. In 2005, the US Institute for Healthcare Improvement made hospital implementation of rapid response teams one of six platforms for nationwide roll-out as part of their campaign to save 100 000 lives from adverse events in hospital (www.ihi.org/IHI/Programs/Campaign). In Australia, the Quality Council has largely replicated this initiative for roll-out in 50 hospitals throughout the country under the Safer Systems Saving Lives Campaign (www.health.vic.gov.au/sssl). In June 2005, although the MERIT study had just been published, the first consensus conference on medical emergency teams found that hospitals should implement such systems.14 Furthermore, none of the hospitals randomised to using medical emergency teams in the MERIT study has subsequently abandoned their use (K Hillman, personal communication 2006).
In the MERIT study, table 2 gives a clue to the discrepancy in results between the single centre studies using historical controls78910 and the MERIT study.13 In a large number of instances where the composite outcome occurred, although the patient had had the criteria for calling the medical emergency team, for whatever reason the staff did not call the team. In intervention hospitals, the medical emergency team was not called before cardiac arrest in 30% of instances when patients had the calling criteria for more than 15 minutes before the arrest occurred. The team was not called in half the incidents leading to unplanned admission to the intensive care unit or unexpected death in hospital. The MERIT study could not measure the effectiveness of the medical emergency team because the randomised intervention was often not received by the patient.
In our hospital the vital importance of ensuring that patients with calling criteria are actually responded to arose largely through the unexpected in-hospital death of a previously well 47 year old man after a thoracotomy in 2001. The family asked the coroner to investigate why a medical emergency team call was not put into place when blood pressure fell and remained low, and also what criteria or symptoms would instigate the medical emergency team process. Part of the cause of death, the coronial inquiry found, was the failure to call the medical emergency team during the 14 hours immediately after the operation, when the patient was tachycardic and hypotensive.15 We recognised that despite our best efforts at hospital-wide education about and implementation of the medical emergency team, patients could die in our hospital because of delayed resuscitation.
Analysis of this death showed a typical example of a clinical futile cycle (fig1)⇓ in which a lot of clinical activity is directed at the patient, but little of this activity relieves the dire circumstances. The bedside nurses did recognise and document the abnormal observations, they did contact the on-call second year doctor, the doctor did attend promptly, and the doctor did recognise that the patient was hypovolaemic and start resuscitation. The junior doctor did discuss the case with the on-call registrar. The nursing staff and the junior doctor were satisfied that the appropriate actions were being taken and that there was no need to call the medical emergency team or other senior assistance.
We identified several important barriers to staff calling for higher order assistance. Firstly, nursing staff were still reluctant to breech the traditional hierarchical referral model of care, even though they knew the patient fulfilled the calling criteria. The junior doctor had responded promptly and started treatment, and also communicated with the registrar, so the nurses were reassured that the situation was in hand. Secondly, over the 14 hour postoperative period, the four different junior doctors who had responsibility for the patient all identified that they were concerned about the patient’s condition, but rather than call the medical emergency team (though they knew that this patient fulfilled the criteria) they all opted to hand the problem either to the next shift or up the hierarchy to the registrar. Finally, although the patient’s physiological variables were abnormal, all staff commented that he looked “too well” to call for the medical emergency team.
This case highlighted that having a medical emergency team based in the intensive care unit, along with telling ward staff about the team and in-service education, was not sufficient. Our two main problems were that ward nurses needed more support for appropriate use of the medical emergency team in our hospital, and that junior medical staff could not consistently recognise and manage appropriately patients who were clinically unstable.16
In our single centre, prospective audit of cardiac arrest in hospital and use of the medical emergency team data, the attending staff collected information from all hospital cardiac arrest calls and medical emergency team calls in 2000-5, making a standardised paper record at the time of the event. The patient’s age and sex, reason for call, treatments given, and outcome were then entered into the intensive care unit’s audit database. Hospital data were downloaded from the hospital’s patient administration system.
If a member of staff assessed a patient and then called a cardiac arrest, this was documented as a cardiac arrest. We feel that this definition is valid in a hospital system, where less critical situations can be responded to by a medical emergency team. The table⇓ gives the incidence of invalid cardiac arrest calls as assessed by the team at the time of the event.
Dandenong Hospital, a 400 bed outer metropolitan teaching hospital, provides comprehensive clinical service (except cardiac and neurosurgery) to a population of 500 000. In 2005 it had 35 644 admissions and more than 50 000 attendances at the emergency department. The intensive care unit was rebuilt from a seven bed to a 14 bed facility in June 2005. With the increased capacity it has about 1000 admissions a year.
Strategies for change
The medical emergency team consists of a senior intensive care nurse (either the nurse in charge or a bedside nurse), one of two intensive care registrars (variable seniority from postgraduate year 3 to preconsultant), and a ward medical registrar (typically postgraduate year 3 or 4). Airway equipment, resuscitation drugs, and fluids are taken in a single roller bag. Resuscitation equipment on the ward has been minimised to basic airway and oxygen devices. The criteria or triggers for calling the team (box 1) are practical, simple, and—most importantly—easy to memorise. Recent studies provide more accurate sensitivity and specificity for various triggers.17 18
Box 1 Criteria or triggers for calling the medical emergency team
Respiratory rate >30 breaths per minute
Respiratory rate <6 breaths per minute
Oxygen saturation <90% on oxygen
Blood pressure <90 mm Hg despite treatment
Pulse rate >130 beats per minute
Decreased level of consciousness
Need of treatment and prompt help
The criteria for cardiac arrest calls are that the patient is unconscious and without a palpable pulse. The cardiac arrest team consists of the medical emergency team plus an anaesthetic registrar and a senior coronary care nurse. In our audit, if a medical emergency team call progresses to a cardiac arrest call, either before the team arrives or at the bedside, the event is classified as a cardiac arrest.
Orientation programme for interns
All first year doctors participate in a one week orientation course in which one of the authors (MB or JH) has since 2000 given a lecture on the academic, practical, clinical, and medicolegal aspects of the management of medical emergencies and the importance of the medical emergency team. Since 2002 the case discussed above has been presented, including insights we gained from our discussions with the family, the root cause analysis, and the coronial inquiry.
Professional development programme for medical registrars
The six day course for medical registrars, started in 2004, aims to develop communication, teamwork, and leadership skills (www.southernhealth.org.au/simcentre). Thirteen hours of this programme are devoted to medical emergency team training: the technical and non-technical skills necessary for the successful management of medical emergencies. Registrars learn and practise a generic systematic approach to ward emergencies (box 2) individually and then as part of a realistic team in a high fidelity simulator along with intensive care and ward nursing staff; interactive lectures cover practical aspects of common emergencies; and the programme includes paper based scenarios and advanced life support workshops. Principles of crisis resource management (box 3) are used to explore and develop non-technical skills. The programme is modeled on Gaba’s description of aviation crew resource management training, in which facilitated video-cued team debriefing follows each scenario.19
Box 2 Systematic approach to clinically unstable patients on the ward
Start by stabilising the patient
Formulate a plan
Communicate the plan
Carry out timely review
Box 3 Key points of crew resource management
Know your environment
Anticipate and plan
Call for help early enough
Take a leadership role
Allocate attention wisely
Distribute the workload
Intensive care liaison nurses
The role of intensive care liaison nurse evolved out of the leaving intensive care non-stressfully and collaboratively programme, which was developed in 2000 in response to actual and perceived needs of patients and their families and the staff at Dandenong Hospital.20 Modelled on work by Russell,9 21 22 it establishes a continuum of care to reduce the patient’s and family’s anxiety during transition to the wards, combining this with a coordinated approach to planning discharge from the intensive care unit. The programme’s objective was expanded to include participation in the medical emergency team service, resulting in the role of liaison nurse.
Clinical expertise, open communication, cooperative interdisciplinary working relationships, and knowledge sharing are integral to the role of intensive care liaison nurse. This nursecan refer patients when the staff is unsure of whether to call the medical emergency team and is responsible for the coordinated care of all patients with tracheostomy tubes.
The liaison nurse follows up 90% of patients discharged from intensive care; half require multiple visits, until physiological variables are stable and psychosocial needs have been dealt with. Although readmission rates have remained consistent, the process of readmission has become better managed.
Key measures for improvement
We assessed the effects of the orientation and professional development programmes, and the evolving role of the liaison nurse, on the incidence of in-hospital cardiac arrests, and monitored the participation of medical registrars in professional development.
Effects of the change
In 2000 we had 2.4 in-hospital cardiac arrests per 1000 hospital admissions; six years later this had decreased to 0.66 cardiac arrests per 1000 admissions (table⇑). The number of medical emergency team calls increased by 46%, from 213 in 2000 to 311 in 2005 (fig 2)⇓. Over the six year audit period the in-hospital cardiac arrests reduced by 24% a year (95% confidence interval 19% to 29%, P<0.001). A Poisson regression model shows an estimated rate of decline of 0.76 (0.71 to 0.82) per year (P<0.001).
Since 2005, 53 medical registrars have completed the professional development programme. The proportion of medical registrars covering medical emergency team calls at Dandenong Hospital who have participated in the programme increased from 48% in 2004 to 76% in 2005. Although objective measures of improved resuscitation outcomes as a result of training are difficult to find, the courses have been enthusiastically received and feedback has been positive. About six weeks after the course, 12 out of 13 registrars reported they had used the knowledge they had gained from the training.
Our audit data show that with appropriate ongoing educational support a medical emergency team system can significantly reduce the incidence of cardiac arrests. The major limitation of this audit is that we have not measured other factors that may have influenced this decline in the incidence of cardiac arrests. Firstly, all oureducational initiatives emphasise making appropriate “not for resuscitation” orders, and the decreased incidence of cardiac arrests could simply reflect this change in practice. Secondly, the number of hospital admissionshas increased over the audit period, which will influence the denominator used for incidence of cardiac arrests. Unlike in our previous study7 we have not performed a case mix analysis, as the service delivery model of our hospital has been unchanged. Finally, we have been unable to obtain similar audit data from comparable hospitals in the region to determine if the decline in cardiac arrests reflects a general change in in-hospital mortality. The latest Australian census indicates a decline in deaths from cardiac causes in the wider community.23 Notwithstanding these limitations, this audit indicates that with an appropriate education programme and leadership initiatives, such as our registrar course and liaison programme the incidence of an important adverse event like cardiac arrest can be decreased. We have used a multifaceted approach rather than a single initiative.
Discussion of the benefits or otherwise of the medical emergency team needs to consider the discrepancy between the data presented in this and previous single centre studies78910 and the data from the MERIT study.13 Were an intervention like the medical emergency team to be considered like a drug or other therapeutic intervention, the difference in level of evidence between a multicentre randomised controlled trial and a single institution study with a historical control would be important. However, the medical emergency team intervention is not like a drug or therapeutic intervention. Firstly, before 2005 no standard definition of a medical emergency team existed: different types of teams are found in different hospitals.14 Comparing the efficacy of such teams in different hospitals is always going to be complicated by differences in composition of the team and type of hospital.
Secondly, in our experience,the hospital staff’s acceptance of medical emergency team concepts is just as important as the actual actions of the team. The main hurdle in our experience is the creation of a supportive environment for general ward nurses to call the team and that provides support for junior medical officers. The intensive care liaison nurse programme has been invaluable in bringing together the general ward patient and the medical emergency team. The intern orientation programme and the medical registrar programme have over the years brought about a culture of strong clinical care, patient safety, and the use of the medical emergency team. Cluster randomisation in the MERIT trial accounted only for hospital size, teaching status, and location, not for liaison nurses and medical education orientation programmes. It would be impossible to randomise for the countless other cultural factors that could determine efficacy in a hospital—support from senior medical staff, positive attitude of the team, administrative support for the process, backup for the intensive care unit, etc.
We have strong support from our senior medical staff support for the medical emergency team. At the same time that we set up the team in this hospital we introduced it in the two local private hospitals where several of our senior medical staff also practised. In private hospitals the consultant was typically the only port of call for the bedside nursing staff when a patient became unstable, but often the responsible consultant could not be contacted. Now, with the medical emergency team (intensive care nurse, hospital nurse coordinator, and an intensive care or emergency department doctor) the patients are reviewed and managed as emergencies until the responsible consultant can attend.
Thirdly, the Hawthorne effect is important: it drives the efficacy of the medical emergency team. In our experience the medical emergency team’s performance is determined by timely feedback to all team members: audit of activity and feedback of missed call opportunities, particularly where poor patient outcomes resulted, to general ward staff both medical and nursing. It has taken us a decade to get the results that are presented in this report. It is hardly surprising that a study like the MERIT study, which had only a four month implementation phase followed by a six month study period, did not show any significant differences.
Our last six years’ experience with the medical emergency team shows a continued sustained decline in in-hospital cardiac arrests. The team’s actual intervention is only one aspect of this: educational initiatives have created a culture and permanent Hawthorne effect to drive these outcomes.
These data are clearly hypothesis generating. Our future work includes analyses of the medical emergency team’s activities and “not for resuscitation” orders, and of a system of electronic graded escalated alerts, which may allow for real time verification of various triggers for these alerts in different populations of patients and tracking of clinical actions.
Contributors: MB has overseen the implementation and development of the medical emergency team, the intern orientation programme, and components of the registrar professional development programme and prepared the manuscript. JH wrote and designed the registrar professional development course. EA developed the nurse liaison programme. SVD designed, developed, and maintained the audit system and database. All authors have contributed to this manuscript and have approved the final version.MB is guarantor.
Funding: No additional funding.
Competing interests: None declared.
Ethical approval: Not required
Provenance and peer review: Not commissioned; externally peer reviewed.