Even though the outcome of children who sustain a cardiac arrest is generally described as dismal, the survival rates from in-hospital cardiac arrest have increased from 9% to 27% in the past 30 years.1,2 However, 43% of those who do survive will have neurological deficits after the arrest.3
Survival of cardiac arrest is influenced by several features, such as time to initiation of first chest compression, first defibrillation, initial rhythm, and postarrest care, with the time to recognition of the cardiac arrest being one of the most important determinants.4 It has been emphasized that the early initiation of high-quality basic life support (BLS) within the first minutes is essential for survival and contributes to a better outcome compared with a delayed start.5–7 For every minute that passes, survival from cardiac arrest decreases by 5.5% to 10% if no adequate cardiopulmonary resuscitation (CPR) is provided.8–10 Despite the importance of the first responders’ interventions, several publications have shown that the initiation of BLS and the quality of actions are often inadequate.11–15
In a hospital, critically ill patients who are at risk for cardiovascular deterioration and thereby ultimately at risk to suffer from cardiac arrest do receive electronic monitoring to promote early recognition of deterioration of their vital signs and immediate response in cardiac arrest.16 However, data suggest that the presence of monitoring confers no additional advantage in adult patients compared with medically witnessed cardiac arrest.4 Furthermore, the presence of a rhythm in the electrocardiography is often falsely equated to cardiac output, which does not apply to pulseless electrical activity (PEA), a common pediatric cardiac arrest rhythm.1 This fallacy could thereby lead to a delayed recognition of cardiac arrest. Adverse outcome for the child in cardiac arrest could be the consequence.
Little is known about how the presence of cardiorespiratory monitoring can influence the first responders’ action in regard to a pediatric cardiac arrest. Therefore, the primary aim of this study was to compare (1) the time to initiation of first chest compression in monitored versus nonmonitored, simulated pediatric cardiac arrest. In addition, we wanted to assess (2) the type and frequency of resuscitation errors defined as deviations from the European Resuscitation Council Guidelines 2010, (3) the subjective performance rating of the participants, and (4) whether monitoring was helpful or distracting. We hypothesized that by misinterpreting the electrocardiograph tracing in simulated pediatric cardiac arrest with PEA, the presence of cardiorespiratory monitoring delays initiation of chest compression, increases deviations of BLS protocols, and subjectively impairs resuscitation performance.
This study was designed as a prospective, single-center, randomized, controlled trial, and it was conducted between April 2013 and February 2014 at the Medical University of Vienna, Austria. After obtaining institutional research ethics board approval (1976/2012) and individual written informed consent, 60 anesthesia or pediatric residents who were frequently involved in the care of critically ill children participated in this trial. They were randomly assigned to either the intervention (monitoring) group or the control (nonmonitoring) group. Before starting the assessment, all participants attended a standardized pediatric BLS and advanced life support refresher course that was 180 minutes in duration. In this course, the European Resuscitation Council Guidelines published in 2010 were theoretically and practically taught to ensure a homogenous level of knowledge and skill.17 The same 5 experienced simulation instructors held these courses in pairs emphasizing the high-quality BLS and the early recognition of the cardiac arrest as recommended by the European Resuscitation Council. In a trainee-to-instructor ratio of 3 to 6 participants per 2 trainers, all participants practiced on the same simulation manikin and were familiarized to the simulation setting.
Each participant was instructed to be the physician responsible for a pediatric patient and that a nurse would be available to help upon request. The nurse was a member of the simulation team and was instructed to be generally helpful but to act on participants’ commands only. Each participant participated in the evaluation phase only once.
In both groups, standardized case briefing was performed outside the simulation room by reading the scenario outline. The scenarios consisted of a 6-month-old boy who was admitted to the hospital because of vomiting, diarrhea, and fever for 3 days. In both scenarios, the participants were given detailed information about the situation, the case history, and the patient’s age and weight by one of the course leaders. The participant was told that he or she would be the doctor in charge for the day and should take a look at the patient who had become abnormally quiet. The introduction had to be repeated by the participant before the assessment.
On entering the simulation room, time measurement started, and the participant encountered the child showing no signs of life, no respiratory movements, and no palpable pulses. In both groups, a peripherally inserted IV access was present at the back of the manikin’s hand. In the monitoring group, the simulator was connected to a monitor showing PEA (sinus rhythm at a rate of 100 bpm but no detectable peripheral oxygen saturation or arterial blood pressure). The PEA triggered a manufacturer preset visual and audio alarm on the monitor, which was not altered by the investigators. In the nonmonitoring group, no monitoring was attached.
Regardless of measures taken, the patient remained in cardiac arrest for the duration of the assessment. After performing 1 minute of chest compressions or when 5 minutes without chest compressions had passed, a code team arrived and took over the patient management, thereby ending the scenario.
SimBaby (Laerdal, Stavanger, Norway) was used as the standard simulation manikin in the refresher course and the assessment scenario. The simulation manikin was placed in a standard pediatric patient bed in a simulation room, and it was operated by an experienced simulation specialist from a separate room. The setup of the simulated environment was the same in both scenarios, and it resembled local standards. The simulated environment was labeled as a general pediatric ward in the nonmonitoring group and a room in an intermediate care ward in the monitoring group. Time measurement started immediately after the participant entered the simulation room. Each scenario was videotaped to allow exact time measurement and analysis of actions. Technical skill performance was measured by a task-specific checklist, which was an internally validated and adapted version of the European Resuscitation Council’s Paediatric BLS Checklist.18
On completion of the scenario, all participants were given a questionnaire and asked to rate their confidence and overall performance on a Likert-like scale ranging from 1 “very good” to 5 “very bad,” and the participants were also asked to rate the perceived realism of the scenario (1 = “very unrealistic,” 5 = “neutral,” and 9 = “very realistic”). They were also asked whether they would suggest further training concerning monitoring errors (yes/no).
Participants in the monitoring group were asked whether they found the monitoring helpful or distracting (1 = “very helpful,” 3 = “neutral,” and 5 = “very distracting”). To maximize the learning effect, all participants received a standardized verbal debriefing after the assessment scenario.
Computer block randomization was performed using the algorithm provided at www.randomization.com (accessed February 12, 2013) before the beginning of the scenario. To ensure even allocation to both groups, blocks of 6 participants were predefined. Sealed and numbered opaque envelopes, containing the random allocation, were opened immediately before the assessment scenario. Demographic data including age, sex, specialty, level of training, previous pediatric resuscitation experience, and regular training were collected.
The sample size was calculated based on the unpublished results and data from Lubrano et al.19 Aiming for a P < 0.05 and power of 95%, a sample size of 54 participants was calculated to detect a clinically important difference of 10 seconds. A SD of ±10 seconds in the 2 groups was expected. To account for any dropouts, 60 participants were studied.
The time to initiation of first chest compression in monitored versus nonmonitored, simulated pediatric cardiac arrest was defined as the primary outcome variable. Other data type and frequency of resuscitation errors, time to initiation of other resuscitation measures, and the subjective performance rating of the participants and whether monitoring was helpful or distracting were defined as secondary, hypothesis-generating outcome variables.
Data analysis was conducted using Microsoft Excel (version 14.3.2, Microsoft Corporation, Redmond, WA), IBM SPSS Statistics (version 22, IBM Corporation, Armonk, NY), and Prism 5 for Mac OS X (version 5.0a, GraphPad Software Inc., La Jolla, CA) for statistical analysis. Statistical analyses of the data were performed using χ2 tests and Student t tests. To account for participants who did not perform chest compressions or secondary resuscitation tasks within 300 seconds, a Kaplan-Meier analysis including log-rank test was performed. Mean and SD of time to event data was calculated without participants who did not perform the task within 300 seconds. Because it is a common practice, results of Likert-like scales were treated as interval measures and thereby analyzed using parametric tests.20,21 A P value <0.05 was considered to represent statistical significance.
Sixty residents were allocated to either the monitoring group (n = 30) or the nonmonitoring (n = 30) group. All residents completed the scenario as intended, and no protocol violations occurred. The distribution of participants was equal in both groups regarding age, sex, level of training, working experience, previous pediatric resuscitations, and any previous resuscitation courses that also covered pediatric basic and advanced life support (Table 1).
In the monitoring group, the time to chest compression was significantly longer than in the nonmonitoring group (91 ± 36 seconds vs 71 ± 26 seconds, hazard ratio, 0.26; 95% confidence interval [CI], 0.14–0.49, P < 0.001). More details are presented in Figure 1. Times to other steps of the algorithm did differ in time to “open the airway,” time to “look, listen and feel,” time to “rescue breath,” and time to “check for signs of circulation.” Details are provided in Table 2 and Figure 2. Participants most frequently missed the following steps: open the airway (14 in the monitoring group and 8 in the nonmonitoring group), look-listen-feel (6 in the monitoring group and 1 in the nonmonitoring group), and check for signs of circulation (13 in the monitoring group and 6 in the nonmonitoring group). In the nonmonitoring group, participants showed better adherence to the 2010 European Resuscitation Council Guidelines with 4 vs 13 participants missing >1 step of the algorithm (Table 3).
In the monitoring group, there were 6 participants who did not start chest compressions within 5 minutes. Instead of initiating BLS measures, these participants made multiple attempts to measure the blood pressure (n = 6) and palpate the pulse (n = 5), reapply the monitoring equipment (n = 6), start mouth-to-mouth or bag-valve mask ventilation (n = 4), administer IV fluids (n = 4), and apply oxygen masks (n = 2) and defibrillator pads (n = 1), and 1 participant intubated the child. Overall, participants who previously attended pediatric resuscitation courses (n = 30) did not initiate chest compressions earlier (77 ± 24 seconds vs 86 ± 41 seconds, hazard ratio, 1.62; 95% CI, 0.91–2.87, P = 0.10).
The subjective ratings of the participants’ overall performance (1 = very good and 5 = very bad) were better in the nonmonitoring group than in the monitoring group (3.0 ± 0.6 monitoring vs 2.5 ± 0.8 nonmonitoring; P = 0.004; 95% CI, 0.2–0.9). Participants in the nonmonitoring group also felt more confident in the scenario (2.9 ± 1.0 monitoring vs 2.5 ± 0.8 nonmonitoring; P = 0.07; 95% CI, 0.0–0.9). The question whether the attached monitoring was helpful or distracting (1 = very helpful and 5 = very distracting) was rated 2.7 in the monitoring group.
This study demonstrates that attached cardiorespiratory monitoring and misinterpreting the monitoring results significantly delay the start of CPR in simulated pediatric cardiac arrest. Furthermore, misinterpreting the monitoring results also negatively impacts adherence to resuscitation guidelines. Of greatest concern, 20% of the participants in the monitoring group did not start chest compressions within 5 minutes of simulated PEA arrest.
There are multiple trials that highlight the necessity to commence high-quality CPR promptly after the onset of cardiac arrest.5,6,11,12,15,22 Delay in providing chest compressions is associated with a decreased chance to achieve return of spontaneous circulation and poor neurologic outcome. Cooper and Cade5 demonstrated that initiation of BLS within 3 minutes of cardiac arrest was associated with a 25% increase in survival compared with a delayed start. Herlitz et al.6 reported that among patients who received CPR within 1 minute after collapse, survival to discharge was even twice that of patients in whom CPR was started later. In our study, the average time to first chest compression was more than 1 minute in the nonmonitoring group, and more than 1.5 minutes in the monitoring group. These findings are in agreement with the previous results reported in pediatric mock codes.11 However, although these mock codes were unannounced and resuscitation attempts were mostly initiated by nursing staff, physicians in our trial received special training and were prepared to perform CPR. However, both groups required >1 minute to initiate chest compressions, highlighting the importance of improving the timeliness of therapeutic response in pediatric cardiac arrests. Most strikingly, the presence of cardiorespiratory monitoring caused a further delay or even prevented the initiation of chest compressions and assessment as well as management of the airway.
For decades, monitoring has been propagated as a tool to increase patient safety and outcome by reducing the time interval between the onset and recognition of clinical deterioration.23,24 Brady et al.4 found that patients suffering from a witnessed and/or monitored cardiac arrest have a significantly higher survival rate with favorable neurologic function compared with those who are neither monitored nor witnessed. However, in this adult CPR trial, monitoring conferred a significant difference in survival only for the first 24 hours. After 24 hours, monitoring did not significantly improve long-term survival compared with witnessed-only cardiac arrest.4 It seems that it is not the monitoring per se that confers survival benefit, but rather survival depends on whether the cardiac arrest is medically detected soon after onset, thereby emphasizing the timely initiation of chest compressions. In our trial, participants in the monitoring group conducted multiple attempts to reevaluate blood pressure and reinstall monitoring tools (e.g., pulse oximetry) in PEA instead of initiating CPR. These data are in agreement with recent clinical findings, where 7 of 15 monitored pediatric patients in cardiac arrest with clinical signs of a pulseless state were classified as “always with a pulse.”25 These findings could be part of the explanation of why monitoring per se does not improve outcome in cardiac arrest. Cardiorespiratory monitoring in PEA arrest seems to be misleading in some cases and therefore delays necessary measures. Thereby, it could ultimately negatively impact outcome. The reason why these misinterpretations occur and consequently lead to decision errors remains unclear. One potential explanation could be that the electrocardiographic morphology in PEA arrests can mimic a rhythm that generates cardiac output.26
In the monitoring group, participants also showed a higher rate of deviations from the 2010 resuscitation guidelines. Several investigations demonstrate that the adherence to the CPR guidelines is often insufficient and that deviations from current treatment algorithms are associated with lower survival rates.10,27–32 Again, the misinterpretation of a regular rhythm on the monitor could have prevented a standardized approach that was performed by most participants of the nonmonitoring group. To guarantee high quality of care in critical situations, it seems to be essential to account for special situations like PEA arrest in monitored children. This should be considered when designing a life support curriculum for professional helpers. It is vital to address the fallacy that a regular monitoring rhythm is always associated with cardiac output and to underline the need to assess the patient for valid signs of circulation. Thereby, cognitive bias that might lead to potential fatal decisions in such patients may be reduced.
Monitoring reduced subjective performance rating and confidence in performing BLS. The conflict between the regular heart rhythm on the monitor and the lack of vital signs could be a cause for this phenomenon. Although the clinical impact of reduced confidence in health care professionals is unknown, findings from lay persons demonstrated that a lack of confidence inhibits CPR commencement and performance.33 Interestingly, the presence of cardiovascular monitoring was rated to be only minimally distracting. However, all participants were very accustomed to monitored patient care, which could have biased this rating.
This trial has some limitations. It was conducted as a single-center manikin-based simulation study among anesthesia and pediatric residents. This study was not designed to assess the quality of chest compressions or clinical outcome in real pediatric patients. However, our results are in agreement with other manikin- and patient-based trials that showed a significant delay in the initiation of BLS measures in cardiac arrest situations.11–15 Although the high-fidelity patient simulator manikin we used resembled many aspects of an actual, approximately 6-month-old baby, it has limitations regarding realism. The manikin’s muscle tone, skin color, and ability to move do not reflect the attributes of a real child. This fact potentially impacted the results by impairing an initial clinical impression. However, the same manikin was used in both study groups, and subjective realism was rated to be high (median 8 of maximum 10 points in both groups). Most of the participants were anesthesia residents, whereas the scenario was based on a normal ward or intermediate care ward setting. Because the ward setting might be unfamiliar to some anesthesia providers, reduced situational awareness might have impaired the early recognition of cardiac arrest. However, all participants of this trial were involved in the acute management of pediatric emergencies because they were members of the hospital medical emergency team on a regular basis and were responsible for the care of children in a pediatric anesthesia-led intermediate care ward.
The cardiac rhythm in the monitoring group did show the morphology of a normal sinus rhythm with a mid-range heart rate. Although PEA is a common initial rhythm in pediatric cardiac arrest, there is hardly any literature available that describes the typical morphology and rate in infants. Even though, in our clinical experience, a PEA with a normal heart rate and morphology of a sinus rhythm is not extremely rare, this specific monitoring pattern might easily be misinterpreted as output-generating rhythm. Another, more obvious PEA morphology, i.e., sinus bradycardia, tachycardia, agonal rhythm, or a shockable rhythm might have resulted in different findings. Furthermore, test situations, such as simulation or mock codes, can substantially impact the participants’ behavior. Therefore, the observed behavior could differ from real-life situations. Knowledge at the end of the refresher course was not assessed. However, because there was no correlation between previous formal BLS trainings and the initiation of chest compressions, differences in BLS knowledge seem to be of minor importance as an explanation for the delayed start of sufficient BLS measures.
Cardiorespiratory monitoring and cognitive bias that lead to misinterpretation of monitoring readings, especially PEA, can significantly delay or even prevent the initiation of essential BLS measures in a simulated pediatric cardiac arrest. In addition, misinterpretation of monitoring in simulated pediatric cardiac arrest can be associated with an increase in deviations from current resuscitation guidelines. The rapid initiation of high-quality BLS has a direct clinical correlation to neurologic outcome and survival in children. Data from this trial may serve as a surrogate for clinical practice. Therefore, these results should directly impact recommendations for future life support training.
Name: Elisabeth Hörner, MD.
Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.
Conflicts of Interest: Elisabeth Hörner is a member and instructor of the Paediatric Working Group of the Austrian Resuscitation Council, the national division of the European Resuscitation Council. However, she was not inappropriately influenced by financial or personal relationships with other people or organizations including employment, consultancies, stock ownership, honoraria, paid expert testimony, patent applications/registrations, and grants or other funding.
Attestation: Elisabeth Hörner has seen the original study data, reviewed the analysis of the data, approved the final manuscript, and is the author responsible for archiving the study files.
Name: Karl Schebesta, MD.
Contribution: This author helped design the study, conduct the study, analyze the data, write the manuscript, contributed equally as first author, and is the co-principal investigator.
Conflicts of Interest: Karl Schebesta is a member and instructor of the Paediatric Working Group of the Austrian Resuscitation Council, the national division of the European Resuscitation Council. However, he was not inappropriately influenced by financial or personal relationships with other people or organizations including employment, consultancies, stock ownership, honoraria, paid expert testimony, patent applications/registrations, and grants or other funding.
Attestation: Karl Schebesta has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.
Name: Michael Hüpfl, MD.
Contribution: This author helped conduct the study and write the manuscript.
Conflicts of Interest: Michael Hüpfl is a member and instructor of the Paediatric Working Group of the Austrian Resuscitation Council, the national division of the European Resuscitation Council. However, he was not inappropriately influenced by financial or personal relationships with other people or organizations including employment, consultancies, stock ownership, honoraria, paid expert testimony, patent applications/registrations, and grants or other funding.
Attestation: Michael Hüpfl has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.
Name: Oliver Kimberger, MD, MSc.
Contribution: This author helped design the study, analyze the data, and write the manuscript.
Conflicts of Interest: Oliver Kimberger declares no conflicts of interest.
Attestation: Oliver Kimberger has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.
Name: Bernhard Rössler, MD, MIH.
Contribution: This author helped conduct the study and write the manuscript.
Conflicts of Interest: Bernhard Rössler is a member and instructor of the Paediatric Working Group of the Austrian Resuscitation Council, the national division of the European Resuscitation Council. However, he was not inappropriately influenced by financial or personal relationships with other people or organizations including employment, consultancies, stock ownership, honoraria, paid expert testimony, patent applications/registrations, and grants or other funding.
Attestation: Bernhard Rössler has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.
This manuscript was handled by: James A. DiNardo, MD.
We thank all participants of this trial for their time and express our gratitude to Dr. Gundula Reichel from the Department of Anesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Austria, and Dr. René Schmutz from the Department of Emergency Medicine, Wilhelminenspital der Stadt Wien, Vienna, Austria, for their on-going support and their comments that greatly improved the study execution. We also like to express our gratitude to the Department of Pediatrics, Medical University of Vienna, Austria, for their support and provision of their equipment and facilities.
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