Brett Patterson

Accuracy of emergency medical dispatchers’ subjective ability to identify when higher dispatch levels are warranted over a Medical Priority Dispatch System automated protocol’s recommended coding based on paramedic outcome data

Objectives: To establish the accuracy of the emergency medical dispatcher’s (EMD’s) decisions to override the automated Medical Priority Dispatch System (MPDS) logic-based response code recommendations based on at-scene paramedic-applied transport acuity determinations (blue-in) and cardiac arrest (CA) findings. Methods: A retrospective study of a 1 year dataset from the London Ambulance Service (LAS) National Health Service (NHS) Trust was undertaken. We compared all LAS “bluing in” frequency (BIQ) and cardiac arrest quotient (CAQ) outcomes of the incidents automatically recommended and accepted as CHARLIE-level codes, to those receiving EMD DELTA-overrides from the auto-recommended CHARLIE-level. We also compared the recommended DELTA-level outcomes to those in the higher ECHO-override cases. Results: There was no significant association between outcome (CA/Blue-in) and the determinant codes (DELTA-override and CHARLIE-level) for both CA (odds ratio (OR) 0, 95% confidence interval (CI) 0 to 41.14; p = 1.000) and Blue-in categories (OR 0.89, 95% CI 0.34 to 2.33; p = 1.000). Similar patterns were observed between outcome and all DELTA-level and ECHO-override codes for both CA (OR 0, 95% CI 0 to 70.05; p = 1.000) and Blue-in categories (OR 1.17, 95% CI 0 to 7.12; p = 0.597). Conclusion: This study contradicts the belief that EMDs can accurately perceive when a patient or situation requires more resources than the MPDS’s structured interrogation process logically indicates. This further strengthens the concept that automated, protocol-based call taking is more accurate and consistent than the subjective, anecdotal or experience-based determinations made by individual EMDs.

Ability of the medical priority dispatch system protocol to predict the acuity of "unknown problem" dispatch response levels.

Objective. To determine if Medical Priority Dispatch Systems (MPDSs) Protocol 32–Unknown Problem interrogation-based differential dispatch coding distinguishes the acuity of patients as found at the scene by responders, when little (if any) clinical information is known. Methods. “Unknown problem” situations (i.e., all cases not fitting into any other chief complaint group) constitute 5–8% of all calls to dispatch centers. From the total patient encounters (n = 599,107) in the aggregate data of one year (September 2005 to August 2006), we examined 3,947 (0.7%) encounters initially coded as “unknown problem” by the London Ambulance Service Communications Center for the scene presence of cardiac arrest (CA) andparamedic-determined high-acuity (blue-in [BI]/“lights andsiren”) findings. Odds ratios (ORs) with 95% confidence intervals (95% CIs) andp-values were used to assess the degree of associations between determinant codes andcase outcomes (i.e., CA/BI). Results. Statistically significant association between clinical dispatch determinant codes andcase outcomes was observed in the “life status questionable” (LSQ; DELTA-1 [D-1]) andthe “standing, sitting, moving, or talking” (BRAVO-1 [B-1]) code pair for the CA outcome (OR [95% CI]: 0.11 [0, 0.63], p = 0.005) andfor the BI outcome (OR [95% CI]: 0.47 [0.28, 0.77], p = 0.003). The LSQ andall three code pairs (i.e., B-1; “community alarm notifications” [B-2]; and“unknown status” [B-3]) also demonstrated significant associations both with the CA outcome (OR [95% CI]: 0.43 [0.23, 0.81], p = 0.010) andwith the BI outcome (OR [95% CI]: 0.74 [0.56, 0.97], p = 0.033). All the determinant code levels yielded significant association between BI andCA cases. Conclusion. This dispatch protocol for unknown problems successfully differentiates dispatch coding of low-acuity andnon-CA patients only when specific situational information such as the patients standing, sitting, moving, or talking can be determined during the interrogation process. Also, emergency medical dispatcher (EMD) reliance on caller-volunteered information to identify predefined critical situations does not appear to add to the protocols ability to differentiate high-acuity andCA patients. LSQ proved to be a better predictor of both CA andBI outcomes, when compared with the BRAVO-level determinant codes within the “unknown problem” chief complaint. The B-3 (completely unknown) determinant code is a better predictor of severe outcomes than nearly all of the clinically similar BRAVO determinant codes in the entire MPDS protocol. Hence, the B-3 coding should be considered—in terms of its predictability for severe outcome—as falling somewhere between a typical DELTA anda typical BRAVO determinant code.

The Medical Priority Dispatch System's ability to predict cardiac arrest outcomes and high acuity pre-hospital alerts in chest pain patients presenting to 9-9-9

OBJECTIVE To establish emergency medical dispatcher (EMD) predictability of cardiac arrest (CA) and high acuity (blue in - BI) outcomes in chest pain patients by using the Medical Priority Dispatch Systems (MPDS) priority levels, and its more specific clinical determinant codes. METHODS A retrospective descriptive study was done on a one years worth of aggregate 999 call data comprising number of patients, calls, incidences, and outcomes (as determined by paramedics) obtained from the London Ambulance Service (LAS). We used Fishers exact test to establish and quantify associations (through odds ratios, 95% CI and p-values) between MPDS priority levels and patient outcomes, stratifying by various pairing of MPDS priority level determinant codes. RESULTS 11.4% of the total calls were classified under the chest pain protocol (MPDS protocol 10). Of all the CA cases (n=3377), 3.1% (n=106) were classified under the chest pain protocol. MPDS priority levels were significantly associated with CA patient outcome (p=0.030) and BI patient outcome (p<0.001). Only the advanced life support response-levels CHARLIE/DELTA pairing was significantly associated with CA outcome (p=0.010) with CA outcome nearly twice more likely in the combined DELTA-priority level codes. ALPHA/CHARLIE and ALPHA/DELTA-level pairings were significantly associated with BI outcome (p<0.001 each), with increased odds of BI outcome in the CHARLIE and DELTA-priority levels. Clinically, the DELTA-level 4 code demonstrated reduced odds of CA and BI outcome when paired with CHARLIE-level patients, than the other DELTA-level patients. CONCLUSIONS Significant associations existed between patient outcomes, as measured in this study, and the MPDS (UKE version) Protocol 10 (Chest Pain) priority levels and specific determinant codes. The (UKE version) DELTA-level 4 determinant code does not belong in the DELTA-priority level, and should be moved to the CHARLE-level, or eliminated altogether--to bring this protocol version in line with other international versions of the MPDS.

The accuracy of emergency medical dispatcher-assisted layperson-caller pulse check using the medical priority dispatch system protocol.

INTRODUCTION Knowing the pulse rate of a patient in a medical emergency can help to determine patient acuity and the level of medical care required. Little evidence exists regarding the ability of a 911 layperson-caller to accurately determine a conscious patients pulse rate. Hypothesis The hypothesis of this study was that, when instructed by a trained emergency medical dispatcher (EMD) using the scripted Medical Priority Dispatch System (MPDS) protocol Pulse Check Diagnostic Tool (PCDxT), a layperson-caller can detect a carotid pulse and accurately determine the pulse rate in a conscious person. METHODS This non-randomized and non-controlled prospective study was conducted at three different public locations in the state of Utah (USA). A healthy, mock patients pulse rate was obtained using an electrocardiogram (ECG) monitor. Layperson-callers, in turn, initiated a simulated 911 phone call to an EMD call-taker who provided instructions for determining the pulse rate of the patient. Layperson accuracy was assessed using correlations between the layperson-callers finding and the ECG reading. RESULTS Two hundred sixty-eight layperson-callers participated; 248 (92.5%) found the pulse of the mock patient. There was a high correlation between pulse rates obtained using the ECG monitor and those found by the layperson-callers, overall (94.6%, P < .001), and by site, gender, and age. CONCLUSIONS Layperson-callers, when provided with expert, scripted instructions by a trained 911 dispatcher over the phone, can accurately determine the pulse rate of a conscious and healthy person. Improvements to the 911 instructions may further increase layperson accuracy.

Past, Present, and Future of Emergency Dispatch Research: A Systematic Literature Review

Abstract previously published in Annals of Emergency Dispatch and Response.

Poster 042. Response Level Determinants Derived from 9-1-1 Callers Versus On-Scene Paramedics

Hypothesis: Response determinant level selection by properly trained emergency medical dispatchers after 9-1-1, second-party caller interrogation, are accurate as compared to response determinants derived from the same interrogation sequence of the first-arriving paramedic after personal patient contact. Methods: Certified emergency medical dispatchers used the Advanced Medical Priority Dispatch SystemTM to interrogate 9-1-1 callers and assign response determinants to 9-1-1 calls received. The first-arriving paramedics then were interrogated retrospectively using the same interrogation sequence. Field providers were blinded to the response determinants selected by the dispatchers and responded with lights and sirens to all calls. Real-time quality control audits were performed on all interrogations to ensure protocol compliance. The response determinants selected by the original dispatchers then were compared to determinants derived from interrogation of the on-scene paramedics. Results: Results are illustrated below:

EMERGENCY MEDICAL DISPATCHERS' ABILITY TO DETERMINE OBVIOUS OR EXPECTED DEATH OUTCOMES USING A MEDICAL PRIORITY DISPATCH PROTOCOL.

Abstract previously published in Annals of Emergency Dispatch and Response

Outcome accuracy of the Emergency Medical Dispatcher's initial selection of a diabetic problems protocol.

INTRODUCTION Diabetes mellitus, although a chronic disease, also can cause acute, sudden symptoms requiring emergency intervention. In these cases, Emergency Medical Dispatchers (EMDs) must identify true diabetic complaints in order to determine the correct care. In 911 systems utilizing the Medical Priority Dispatch System (MPDS), International Academies of Emergency Dispatch-certified EMDs determine a patients chief complaint by matching the callers response to an initial pre-scripted question to one of 37 possible chief complaints protocols. The ability of EMDs to identify true diabetic-triggered events reported through 911 has not been studied. OBJECTIVE The primary objective of this study was to determine the percentage of EMD-recorded patient cases (using the Diabetic Problems protocol in the MPDS) that were confirmed by either attending paramedics or the hospital as experiencing a diabetic-triggered event. METHODS This was a retrospective study involving six hospitals, one fire department, and one ambulance service in Salt Lake City, Utah USA. Dispatch data for one year recorded under the Diabetic Problems protocol, along with the associated paramedic and hospital outcome data, were reviewed/analyzed. The outcome measures were: the percentage of cases that had diabetic history, percentage of EMD-identified diabetic problems cases that were confirmed by Emergency Medical Services (EMS) and/or hospital records as true diabetic-triggered events, and percentage of EMD-identified diabetic patients who also had other medical conditions. A diabetic-triggered event was defined as one in which the patients emergency was directly caused by diabetes or its medical management. Descriptive statistics were used for categorical measures and parametric statistical methods assessed the differences between study groups, for continuous measures. RESULTS Three-hundred ninety-three patient cases were assigned to the Diabetic Problems Chief Complaint protocol. Of the 367 (93.4%) patients who had a documented history of diabetes, 279 (76%) were determined to have had a diabetic-triggered event. However, only 12 (3.6%) initially assigned to this protocol did not have a confirmed history of diabetes. CONCLUSIONS Using the MPDS to select the Diabetic Problems Chief Complaint protocol, the EMDs correctly identified a true diabetic-triggered event the majority of the time. However, many patients had other medical conditions, which complicated the initial classification of true diabetic-triggered events. Future studies should examine the associations between the five specific Diabetic Problems Chief Complaint protocol determinant codes (triage priority levels) and severity measures, eg, blood sugar level and Glasgow Coma Score.