Abstract & Commentary
Medical Emergency Team Calls in the Radiology Department
By David J. Pierson, MD, Editor, Professor Emeritus, Pulmonary and Critical Care Medicine, University of Washington, Seattle, is Editor for Critical Care Alert.
Synopsis: This study of potentially life-threatening changes in patient condition during trips to the radiology department of a large academic medical center found that such events occurred about once a week, involved both ward and ICU patients who had comorbidities and high overall mortality, and were often unanticipated by vital sign changes or other recognized warnings.
Source: Ott LK, et al. Medical emergency team calls in the radiology department: Patient characteristics and outcomes. BMJ Qual Saf 2012; 21:509-518.
Ott and colleagues at the University of Pittsburgh reviewed all medical-emergency team (MET) calls to the radiology department involving adult inpatients during a 2-year period. They sought to identify the characteristics of the patients involved, and to find any relationships between these characteristics and patient outcomes. Activation of the hospital's well-established MET system occurs when patients experience deterioration in respiratory, cardiovascular, or neurological status, or develop other predefined alterations in symptoms, signs, or interventions, using standardized criteria. MET calls originating during transport to or from the radiology department were not considered in the study. The authors recorded the timing and circumstances of each MET call, the patient's origin (e.g., ward or ICU), demographic and diagnostic data, the Charlson Comorbidity Index, plus vital signs and level of care needs in the 12 hours prior to the call. In addition, the level of care given in the radiology department was sought from the electronic medical record, as was information on the level of care required following the call and whether the patient died in the hospital after the event.
During the 2-year study period, there were 111 MET calls to the radiology department. Patients were sent for CT (44%), MRI (22%), interventional radiology (15%), and other imaging. Calls happened more frequently on days near the middle of the week and during the hours from 8 a.m. to noon, although they also occurred at other times. Almost half (43%) of the MET calls occurred on the patients' first day in the hospital. Forty percent of the patients came to the radiology department from an ICU, and 60% from the wards. Fifteen percent were mechanically ventilated, 12% were on an oxygen facemask, and 38% had nasal oxygen, while only 35% of the patients arrived in radiology on no respiratory support. After the MET call, most patients (78/111, 70%) required a higher level of care than before, including 38 of the 67 non-ICU patients; 26% of those not on mechanical ventilation before the call required it afterwards.
Patients generating MET calls in the radiology department tended to be middle-aged, and there was no gender difference. They were evenly distributed across diagnostic categories, and tended to have comorbidities (renal 61%, cerebrovascular 28%, diabetes 22%, myocardial infarction 21%, cardiopulmonary disease 20%), with a mean Charlson Comorbidity Index of 4. During the 12 hours preceding the MET call, 16% had reached or exceeded the institution's MET vital sign threshold. More than half of the patients received continuous monitoring while in the radiology department.
Twenty-five percent of patients who experienced a MET call in the radiology department died. Mortality was higher among ICU-originating patients than in those coming from the ward (57% vs 43%; P = 0.03). Aside from this, the only association with a fatal outcome following the MET call was for having received inotropic medications and/or fluid resuscitation in the 12 hours prior to the call (39% vs 17% of the patients who died; P = 0.02).
This study is helpful in that it provides a systematic look at a large consecutive series of patients in a tertiary referral center for whom the MET system was activated while they were in the radiology department for imaging or procedures. Intensivists and other hospital clinicians dread the "stat" page to the radiology department, and they know that the acute patient deterioration that triggers such calls occurs not infrequently. A hope in conducting a study like this is that patterns and predispositions can be identified that will permit effective preventive measures to be implemented. However, Ott et al had no such good fortune. In documenting the wide variety of patient characteristics and clinical factors present in this series, the authors are careful to point out that nothing can be concluded about causation or specific measures to take in the future. Nonetheless, they have better described a clinical scenario that is both frequent and associated with high patient mortality. One may hope that future studies can identify ways in which the incidence of radiology department MET calls can be reduced and their outcomes improved.
As pointed out in the accompanying editorial by Staples and Redelmeier,1 there are a number of possible explanations for acute patient deterioration in the radiology department. Of these, the two most likely are, first, that seriously ill patients are likely to need complex studies requiring imaging, and are also predisposed to complications associated with both intrahospital transport and the performance of the procedures. Imaging procedures may be ordered because of patient deterioration or suspicion of a new medical process, settings in which adverse events may be particularly likely. And, second, caring for a complicated, potentially unstable patient during transport and imaging-related interventions presents major challenges, including the following:
- The procedure and associated waiting can take considerable time.
- The patient must be moved, positioned, and otherwise physically manipulated.
- The administration of various contrast agents and sedatives may be required.
- Lines may come out, infusions may be interrupted, and scheduled medication doses may be missed.
- Physicians and other caregivers may be distracted by aspects of the procedure.
- Patients may experience anxiety, agitation, claustrophobia, or other distress.
Although the present study does not tell us how to prevent MET calls to the radiology department or how to improve outcomes when they occur, it casts light on an important problem affecting all who work in the ICU.
- Staples JA, Redelmeier DA. Medical emergencies in medical imaging. BMJ Qual Saf 2012;21:446-447.