Clinical paperEffect of a Medical Priority Dispatch System key question addition in the seizure/convulsion/fitting protocol to improve recognition of ineffective (agonal) breathing☆
Introduction
The grand mal seizure (or convulsion, fit) has long been a common but problematic condition reported to emergency communication centers.1 Its often dramatic presentation can surprise onlookers and impact the ability of emergency callers to precisely report surrounding symptoms, concurrent conditions, history, and the changing nature of variously encountered seizure types, specifically generalized convulsions.2 A patient having a major seizure usually traverses a predictable course of events: prodrome (at times), onset of the event, followed by a tonic (tetanic) phase of muscle tightening and rigidity, replaced by a clonic phase of mild twitching to strong jerking movements, which then usually fade to a secretory phase of hypersalivating and drooling. The recovery (post-ictal) phase is a predictably welcome event but, unfortunately, some patients do not recover at all. The cause of their event, in these cases, is not specifically a brain or metabolic disorder (such as epilepsy) but an anoxic event coinciding with a cardiac arrest or other sudden non-perfusing heart rhythm. The frequency of anoxic seizures within the entirety of seizure events reported to emergency communication centers is currently not known. What is known is that they can be confused for the more common variety of convulsions that eventually result in an automatic recovery of central and bodily functions – to a patient's obvious detriment – since EMS response may be downgraded in both time-priority and resources dispatched, when the Emergency Medical Dispatcher (EMD) suspects a common, non-life-threatening seizure condition. Emergency Medical Dispatchers must be armed with the correct information to make the best, most accurate, response decisions for such patients.
All changes to the Medical Priority Dispatch System (MPDS) are approved by the International Academies of Emergency Dispatch (IAED) Council of Standards. The decision of the Council to add the intervention question to address the issues stated above was hotly debated. Much of the discussion centered around the best way to ascertain effective breathing over the phone. The scripting “Is s/he breathing normally?” was entertained but was ultimately felt to be too subjective when interpreted by lay callers. The scripted question “Is s/he breathing regularly?” initially received only mixed reviews from the Council, as there were isolated anecdotal reports that this question may be ambiguous, and not well understood by the callers. “Breathing regularly” has at least two basic interpretational meanings: uniform periodicity and/or unlabored breathing (like “normal”). Each subcategory of definition could contribute to the effectiveness of a caller's ability to identify what is sought by the use of the word “regularly”.
This study examines the impact of a recent modification to the protocols used by the EMD to assess seizure patients.
Section snippets
The protocols
The International Academy of Emergency Medical Dispatch (IAEMD) maintains the Medical Priority Dispatch System Protocol in use in over 2900 communication centers. The protocol includes “Key Questions”, designed to elicit from callers specific patient conditions that result in a dispatch triage classification, or “determinant code” (Table 1). Each determinant code fits into a “priority level” (ALPHA, BRAVO, CHARLIE, and DELTA) that purports the urgency and relative acuity of the patient. An
Hypothesis
The use of a new assessment key question in the seizure protocol (MPDS version 11.2) significantly improves the ability of the EMD to identify the presence of agonal or ineffective breathing, and correctly categorize those symptoms in the high-acuity (DELTA level) patient code.
Methods
The IAEMD utilizes a unified protocol model in which all MPDS users employ the same protocol—with only language and approved limited cultural variations. MPDS version changes are introduced systematically, with training updates and protocol software upgrades provided to users in advance of on-line implementation. London Ambulance Service (LAS) which is regarded as the largest emergency medical communication center in the world, processed 1.1 million calls for medical assistance in 2005 using
Results
Overall, the percentage of patients, calls, incidents, responses, and patient BI and CA outcomes increased with increasing determinant code level, i.e., from ALPHA to DELTA, in each protocol (Table 2). The percentage of CA outcome in the 12-A-1 descriptor code in protocol version 11.2 was lower than in version 10.4 (0.18% vs. 0.24%) (Table 3). However, the percentage of CA outcome was higher in the protocol version 11.2 than in protocol version 10.4 (0.38% vs. 0.29%), for the combined
Discussion
This “before” and “after” study data demonstrates that the desired effect of the isolated key question addition to version 11.2 of the protocol was successful, resulting in the additional capture of 22 CA patients in the new 12-D-3 “Irregular Breathing” determinant code. While some of these patients might have otherwise been categorized in another DELTA code, the comparison of distributions in Table 1 shows similar CA numbers in all other determinant codes with the exception of this new code
Limitations
Dispatch protocol studies must establish that what was studied was the result of a protocol's scripted design and not the collective amalgamation of what the corps of calltakers’ subjective or arbitrary decision making ultimately produces.11 The truest method of assuring this is audio call review of each case with only compliant cases as an inclusion requirement. In numerically large call studies, this may not be practical, and in our case we used the overall proven high compliance level method
Conclusion
In a small number of cases, cardiac arrests actually present as recovering seizure patients to the EMD using the established (but less recent) MPDS protocol questions. Adding a new intervention question regarding “breathing regularly” to the dispatch question sequence in the MPDS seizure protocol provides a valuable tool for identifying true cardiac arrest cases. These findings suggest that some cases that would have been classified in the 12-A-1 descriptor code in the old protocol version
Conflict of interest
JC is the CEO and Medical Director of the Research and Standards Division of Priority Dispatch Corp. and a member of the Council of Standards, Board of Certification, and Board of Trustees of the International Academies of Emergency Dispatch. He is the inventor of the Medical Priority Dispatch Protocol and Quality Assurance System studied herein. BP is Academics and Standards Editor for the IAEMD and Chair of the IAEMD Council of Research. CO is a medical informatics researcher and
Acknowledgments
We wish to thank the London Ambulance Service Trust – its Emergency Operations (Communication) Center, The Quality Assurance Unit, corps of 360 Advanced EMDs, and Mr. Mike Damiani Management Information Analyst, and provided the call data for this study. Also the Department of Medical Informatics, University of Utah, who have allowed one of the authors (C. Olola) to work with the IAEMD Academics & Standards Division on developing more structured and valid dispatch research. Sincere thanks to
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A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2008.06.006.