ARTICLE |
a Clinical Quality Safety Unit
d Intensive Care Unit
f Department of Neonatology, Royal Children's Hospital, Melbourne, Australia
b School of Nursing
e Department of Paediatrics, University of Melbourne, Melbourne, Australia
c Murdoch Children's Research Institute, Parkville, Victoria, Australia
| ABSTRACT |
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PATIENTS AND METHODS. We conducted an audit of prospectively collected medical emergency team forms and a retrospective review of medical charts during an 18-month period at a tertiary pediatric hospital in Australia. Critical events were defined as cardiac arrest, endotracheal intubation on the ward, reversal of analgesia or sedation, fluid resuscitation at
40 mL/kg, hyponatremia (serum sodium level of
125 mmol/L), hypernatremia (serum sodium level of
155 mmol/L), hypoglycemia (glucose level of
2 mmol/L), or severe metabolic acidosis (pH
7.1).
RESULTS. A total of 172 children had 225 medical emergency team calls (10.6 calls per 1000 hospital admissions and 2.0 calls per 1000 patient-days). Forty-two percent of calls were for infants <1 year old. Preexisting chronic disease was common, with 20% having a chronic underlying neurologic disorder. Forty-four percent of the children were postoperative. The mortality rate of the 172 children was 7.6% in the hospital and 13.4% within 1 year. Thirty-three children had a critical event, with reversal of analgesia being the most common event (n = 11). Postoperative children were more frequently seen in the critical-event group (64% vs 40%). Hospital and 1-year mortality rates were higher for children who had a critical event (16.1% vs 22.6%, respectively) than those who did not (5.7% vs 11.3%).
CONCLUSIONS. Chronic and complex illnesses were prevalent among children provided with urgent medical assistance from the medical emergency team in a tertiary hospital. Children in the postoperative phase were overrepresented among those with a critical event. A critical event significantly increased the risk of hospital mortality. Greater knowledge of high-risk groups is required to further improve outcomes for hospitalized children.
Key Words: critical illness child cardiopulmonary resuscitation medical emergency team mortality morbidity
Abbreviations: MET—medical emergency team CI—confidence interval
It is well recognized that, although deaths and adverse events that occur in hospitals are sometimes unavoidable, many can be prevented.1–4 The implementation of medical emergency teams (METs), rapid response teams, or outreach teams in hospitals is a strategy to improve the identification and prompt management of seriously ill patients before a major deterioration occurs. There is some evidence that these early intervention systems may reduce mortality and morbidity in adult settings,5–9 although the only cluster-randomized, controlled trial reported to date evaluating the MET system failed to demonstrate any significant reductions in a combined measure of cardiac arrest, unexpected deaths, and unexpected admissions to an ICU.10
Despite the increasing adoption of early intervention systems for hospitalized children,11 there is a lack of evidence to guide the system development. The first evaluation of the implementation of a pediatric MET service in our institution demonstrated an overall reduction in cardiac arrest from 0.19 per 1000 to 0.11 per 1000 admissions (risk ratio: 1.71; 95% confidence interval [CI]: 0.59–5.01) and unexpected hospital deaths from 0.12 per 1000.00 to 0.06 per 1000.00 admissions (risk ratio: 2.22 [95% CI: 0.50–9.87]), although these differences were not significant.12 This study also highlighted the relatively low incidence of cardiac arrest in hospitalized children compared with adults. More recently, Brilli et al,13 from a large pediatric teaching hospital in the United States, demonstrated a significant reduction in the combined measure of respiratory and cardiac arrests with the introduction of an MET service. There are also other critical events, where earlier recognition and/or intervention could potentially reduce the severity of illness and improve outcomes for hospitalized children. Such critical events include the provision of intubation, reversal of analgesia or sedation, and severe electrolyte or metabolic complications.
An understanding of the nature of illness and identification of MET outcomes is vital for further improving standards of practice and the delivery of quality care to seriously ill children. The purpose of this study was to describe the clinical profile of the children referred to the MET system during an 18-month period at a pediatric referral hospital. The aims of the study were to describe (1) characteristics of hospitalized children who require a MET call, (2) reasons for the MET call, (3) incidence of critical events associated with the MET call, (4) outcomes of these children, and (5) a comparison of characteristics and outcomes of children who had a critical event with those who had an MET call and did not have a critical event.
| MATERIALS AND METHODS |
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5 million people. All of the medical and surgical services are provided in the 250-bed hospital, including, trauma, cardiac surgery, extracorporeal membrane oxygenation, organ transplantation, and an emergency retrieval service. The hospital admits
33 000 patients each year, of whom
18 000 stay longer than 24 hours. Approximately 1400 patients are admitted to the ICU each year. There is a separate NICU, but no high-dependency unit.
Details of MET Service and Calling Criteria
The MET service is available 24 hours per day, 7 days per week. The MET was implemented at the Royal Children's Hospital in September 2002 and replaced the conventional "cardiac arrest team" that had operated previously for the management of cardiorespiratory arrest on the wards. The team is composed of an ICU doctor, ICU nurse, emergency department doctor, and a hospital medical registrar, who respond immediately to assess a child who is, or is at risk of becoming, seriously ill. A list of criteria is displayed prominently in posters on the wards to guide clinical staff regarding when to call MET. The criteria, which have been reported elsewhere,12 are based on abnormal, age-related changes in heart rate, respiratory rate, and blood pressure; decreased oxygen saturation; and signs of increasing respiratory distress and altered neurologic status. In addition, there is a general category of "doctor or nurse worried about a child's clinical state."
Methods of Data Collection
A retrospective audit was conducted of the data-collection forms designed for MET (prospectively collected) and the medical charts of all of the inpatients who had an MET call during an 18-month period (December 2002 to June 2004). This period was chosen because it coincided with the introduction of the MET service, after a 3-month transitional period. The study included patients who were the subject of our previous report describing the impact of the MET after its first year of operation.12 The records of all of the MET calls were maintained by using a modified Utstein format, a standardized method for recording and reporting pediatric cardiac arrest.14 MET data-collection forms were completed by the nursing or medical staff attending the MET call and later collected by 1 investigator (Ms Kinney). Information was collected from the data sheets and from the patients medical charts and included patient demographics, diagnoses and comorbidities, the main reason for the MET call, location, day of week and time of call, hospital stay characteristics (previous surgery, previous ICU admission, and length of stay in ICU and/or hospital), and patient outcomes, including survival to hospital discharge and 1 year post-MET intervention. Information on the number and details of hospital and ICU admissions was obtained from the hospital and ICU electronic databases. Hospital admissions, patient-days, and hospital mortality are related to the number of admissions that were >24 hours. Knowledge of the child's death was contingent on the child having died in the hospital or death being reported to the hospital, so it is possible that some cases were missed.
The study was approved as a clinical audit by the chair of the Royal Children's Hospital Ethics in Human Research Committee and registered at the human research ethics committee at the University of Melbourne.
Data Analysis and Statistical Methods
A standardized system of coding diagnoses and reasons for admission to ICUs in Australia and New Zealand was used to classify patient diagnoses and comorbidities.15 From a choice of 370 codes, each MET call was coded according to principal diagnosis (ie, the main diagnosis responsible for the MET call), principal underlying diagnosis, and
5 associated diagnoses. For example, a child with cerebral palsy and pneumonia is classified with a principal diagnosis of "pneumonia" and an underlying diagnosis of "encephalopathy, chronic static (eg, cerebral palsy)." The child may also have associated diagnoses, such as scoliosis or seizures. Associated diagnoses also included postprocedural or operative diagnoses, which were used to code surgical procedures that occurred during the current hospital admission but before the MET call. An infant with bronchiolitis and no other underlying diagnoses is classified with "bronchiolitis" as both the principal diagnosis and underlying diagnosis. Information was also collected with respect to critical events precipitating or occurring during the MET. Definitions of the critical events are provided in Table 1. They exclude critical events occurring in the operating theaters or recovery room, eliminating events that related to the conditions of surgery and anesthesia.
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2 analyses. Continuous, nonparametric variables were compared with the Mann-Whitney test. Statistical analyses were performed by using the statistical package Stata 9.2 (Stata Corp, College Station, TX). P values of <.05 were accepted as statistically significant. | RESULTS |
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Patient Demographics
Forty-eight percent of children were boys (n = 109). The median age was 15.1 months (interquartile range: 4.2–77.9 months). Forty-three percent of calls were for infants <1 year old, whereas during this same period infants composed 14% of all of the admissions to the hospital. Twenty-nine percent of the children were between 1 and 5 years old, 11% were between 5 and 12 years old, and 17% were >12 years old. The median weight was 10 kg (interquartile range: 5.3–23.0 kg).
Clinical Characteristics
The 10 most frequent principal diagnoses that were considered directly responsible for the MET call are outlined in Fig 2. Respiratory failure was the most frequent reason for an MET call. The 10 most frequent principal underlying diagnoses are summarized in Fig 3, along with the number in a postoperative phase. Many of the children had chronic health problems, with 20% having a chronic encephalopathy as the principal underlying diagnosis. Nearly half (49%) of the children had
2 other coexisting diseases.
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Thirty-six percent of children (n = 80) had a previous admission to the ICU, and the MET call occurred within 24 hours of discharge from the ICU for 29% of these children (n = 23). Twenty percent of children (n = 44) had a previous MET call during their hospital stay, and 32% of these occurred within 24 hours of the most recent MET call (n = 14). Of the 44 children who had a previous MET call, 59% (n = 26) were transferred to ICU, 68% (n = 30) were postoperative, and 73% (n = 32) had a previous admission to ICU.
Forty-nine percent (n = 110) of the children who had a MET call were transferred to the ICU. Another 18 had a later unexpected admission (within 24 hours) to the ICU. During the same study period, there were 448 nonelective admissions to the ICU from the wards (ie, excludes elective or nonelective admissions from the operating theater, emergency department, or via the neonatal or pediatric emergency transfer service). Therefore, 25% of the unplanned admissions to ICU from the ward occurred via the MET system. For those patients transferred via MET to the ICU, the median length of stay in the ICU was 2.3 days (interquartile range: 0.8–5.3 days).
Hospital length of stay ranged from 1.0 to 360.0 days, with a median of 16.0 days (interquartile range: 7.0–39.0 days). This compares with an average length of stay of 5.1 days for patients admitted to the hospital for >24 hours during the same time period.
Mortality
Because there were children who had multiple MET calls during the study period, the mortality data are derived from a total of 172 individual children. Additional details of the deaths are provided in Fig 1. Although there were only 2 unexpected deaths within 24 hours of the MET call, 13 of the children did not survive to hospital discharge. The total number of admissions was 181, giving a hospital mortality rate of 7.18%. In contrast, the hospital mortality rate was 0.54% (n = 114) of the 20 979 admissions that did not have a MET call (risk ratio: 13.21 [95% CI: 7.58–23.02]; P = .00). It is not known how many of the deaths in this latter group were unexpected.
Critical Events
Critical events associated with the MET calls are outlined in Table 3 and have been identified as potentially life-threatening situations that occur just before or during the MET call. Critical events composed 14.7% of all of the MET calls; 33 occurring in 31 children. The most common critical event involved the administration of naloxone, an opioid antagonist, used to reverse the effects of opioid toxicity. This was administered during 11 MET calls (10 children), and 1 of these children was also intubated. All but 1 child was receiving opioids during the postoperative period. The provision of intubation was the next most frequent critical event. Four children were intubated for cardiac failure, and the other 5 were intubated for hypovolemic shock, septic shock, respiratory failure, increased intracranial pressure, and seizures. There were 7 cardiac arrests recorded. One child with bacterial endocarditis arrested twice with sudden cardiac dysrhythmia and died after the second cardiac arrest. The other reasons for cardiac arrest were cerebral hemorrhage, pulmonary hypertensive crisis, respiratory arrest for a child with cerebral palsy postorthopedic surgery, bradycardia that developed during the intubation of an infant with a chylothorax, and a vagal-mediated bradycardia that was associated with the insertion of a nasogastric tube. The 2 children with hyponatremia were being treated for cancer, and both of the MET calls were made for prolonged seizures.
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| DISCUSSION |
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Forty-two percent of patients in the MET system were <1 year of age. This finding is similar to studies of in-hospital pediatric cardiac arrest, where 50% to 61% of children were noted to be <1 year of age.16–18 It indicates the vulnerability of this age group, who may warrant closer observation and monitoring.
Chronic and complex illnesses were common features among children in the MET system. Approximately 20% had a chronic underlying neurologic disorder, with the most frequent principal underlying diagnosis being cerebral palsy. It is known that children with severe cerebral palsy have a reduced life span.19,20 A common cause of death is pneumonia,20 and pneumonia or respiratory failure was found to be a frequent reason for a MET call among this group of patients. Preexisting chronic diseases are also prevalent in children who have a cardiac arrest, with 1 study reporting 71% of children who needed resuscitation, having a chronic disease on admission.17
Approximately 10% of the MET calls were made for children shortly after ICU discharge. There was no attempt to ascertain whether there were shortcomings in the ICU discharge process. Many of the MET calls were for children during the postoperative phase, and, likewise, any deficiencies in the ICU referral process or discharge process from the postoperative recovery room were not determined. For those children in the postoperative phase,
50% of the MET calls occurred within 3 days of the surgery, highlighting the importance of close monitoring during this time. Some of these children may benefit from a higher level of care than can be provided on the ward. Our hospital does not have a high-dependency unit. The MET system has also been shown to be effective in reducing mortality and morbidity among adult patients undergoing major surgery.21
Comparison With Other Studies
Most studies of MET systems have been conducted in adults, making a comparison of characteristics and outcomes difficult. Furthermore, it is not always clear whether the number of hospital admissions used for determining the MET call rate excludes day stay patients. The rate of MET calls in our institution, 10.6 per 1000 admissions is similar to the 8.7 per 1000 admissions reported in the multicenter study of Australian hospitals.10 However, the MET call rate of 2.0 per 1000 patient-days is
7 times greater (0.3 per 1000 patient-days) than that reported from a pediatric hospital in the United States after their first year of MET implementation13 and similar to 3.1 per 1000 patient-days after the implementation of a nurse-led rapid response team in another pediatric hospital in the United States.22 Hospitals that have had a MET service established for a longer period of time have reported higher rates of MET calls. A large tertiary hospital in the United States reports a rate of 25.8 per 1000 admissions after
7 years of operation,8 and the rate of MET calls rose to
33.0 per 1000 admissions after 4 years in an Australian teaching hospital.23
Respiratory compromise (66%) was the most common reason for a MET call to be made, and cardiovascular changes (13%) were the least frequent. Respiratory concerns were also common reasons for activating the MET or rapid response team in 2 other pediatric studies.13,22 In comparison, a study of 713 MET calls in an adult hospital demonstrated that the 3 most frequent reasons for calling the MET were an altered conscious state (22%), hypotension (20%), and tachypnea (15%).24 Another study of 400 MET calls in an adult teaching hospital demonstrated that hypoxia (41%) was the most common reason to initiate an MET call, followed by hypotension (28%) and a change in conscious state (23%).25 These differences are not surprising, because respiratory problems are known to be common in children, and hypotension is regarded as a late sign of shock.26 There were only 2 children who required extensive fluid resuscitation during the MET call and no cases of severe metabolic acidosis, suggesting that shock had rarely progressed to an extreme status before the MET call in the cohort described here.
Strengths and Limitations
To our knowledge, we report the first detailed analysis of a group of hospitalized children who were provided with a MET intervention while they were inpatients in a pediatric tertiary referral center. Unique to our study of a MET system, we have also identified outcomes other than cardiac or respiratory arrest, unplanned admissions to ICU, and unexpected death from which to gain a better understanding of patient deterioration in the pediatric setting. The critical events were identified because they were either related to a higher risk of mortality or ongoing morbidity or the severity of illness indicated that avoidable clinical deterioration may have occurred. The proportion of children who were in a postoperative phase was significantly greater for children who had a critical event than those that did not. Hospital mortality was higher for children who had a critical event compared with those who did not have a critical event, but the difference was only just statistically significant (P = .046).
There are several limitations to our study. The data are now 3 years old and reflect the initial introduction of the MET service. It was an observational study, and we did not seek to evaluate the effectiveness of the MET system. We did not attempt to evaluate those children who did not receive a MET review but may have fulfilled the MET criteria and/or those who were admitted to the ICU. It is possible that some children may have suffered a critical event and were not the subject of a MET call (eg, reversal of analgesia), although it is very unlikely that a child suffered a cardiac arrest or was intubated without the involvement of the MET. The study was a retrospective review of the MET data records and patient medical charts, and MET data sheets may have been missed if staff did not complete the documentation at the time of the MET call. Finally, the study was conducted in a single pediatric tertiary institution; therefore, the findings may not apply to other hospitals.
Implications of Findings
Since the findings of this audit, there have been a number of quality improvement changes made that may further benefit this group of children. These include changes to the standard naloxone orders and the frequency of the pain service rounds, the introduction of an ICU liaison nurse position,27 and recommendations for preventing hyponatremia.28 Future research could investigate whether such critical events could be potentially prevented by an earlier MET call or other changes to hospital processes.13,29
Only 25% of unplanned admissions from the wards to ICU occurred via the MET system. Although the majority of unplanned ICU admissions occurred after the "less urgent" review process of direct consultation with ICU staff, it may also reflect a relative underuse of the MET service. A survey of medical and nursing staff would assist in identifying any barriers to using the MET service. One study, in a hospital where the MET service had been in operation for many years, found that the majority of nurses would still call the covering doctor for a sick patient before seeking the MET.30
Finally, there has been little investigation of pediatric scoring systems31,32 or the MET criteria to help identify seriously ill children in the hospital wards. The ability of the MET criteria to identify children who have critical events could also be examined in future studies.
| CONCLUSIONS |
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1 in 7 calls: ICU admission in 50% and hospital mortality in 8%. The children for whom MET calls were made were frequently <1 year of age, were in the first 3 postoperative days, and had an underlying chronic neurologic disorder. Children who had critical events had higher hospital mortality and were more likely to be postoperative than the children who did not have a critical event. This study provides important baseline data to assist the research efforts to identify and improve the management of seriously ill children on the wards.
| ACKNOWLEDGMENTS |
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We thank the nursing and medical staff who completed the MET forms.
| FOOTNOTES |
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Address correspondence to Sharon Kinney, RN, MN, Clinical Quality Safety Unit, Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052, Australia. E-mail: sharon.kinney{at}rch.org.au
The authors have indicated they have no financial relationships relevant to this article to disclose.
| What's Known on This Subject Early intervention systems, such as a MET, are strategies for improving the identification and prompt management of seriously ill patients before a major deterioration occurs. Such systems seem to reduce hospital mortality and morbidity rates.
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| What This Study Adds Hospitalized children provided with a MET intervention were frequently <1 year of age, postoperative, and with a chronic illness. A high-risk subgroup of children experiencing a critical event was associated with an increased risk of hospital mortality.
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| REFERENCES |
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