Effect of a Medical Priority Dispatch System key question addition in the seizure/convulsion/fitting protocol to improve recognition of ineffective (agonal) breathing.

OBJECTIVE: To investigate the impact of a new assessment question in the Medical Priority Dispatch System (MPDS) seizure protocol on the ability of the Emergency Medical Dispatchers (EMDs) to identify the presence of agonal or ineffective breathing. METHODS: A retrospective comparative study was conducted using two datasets-each representing two versions of the MPDS protocols (version 10.4 and version 11.2) at the London Ambulance Service (LAS). The "before" dataset (April 2004 to March 2005, version 10.4) did not have a specific assessment Key Question to identify the presence of irregular/agonal breathing. The question was added in the "after" dataset (April 2005 to March 2006, version 11.2). The datasets comprised the number of patients, calls, responses, incidents, and outcome (i.e., cardiac arrest [CA] and blue-in [BI]) parameters categorized using MPDS determinant codes. A distribution of these parameters was stratified by protocol version. Two-by-two contingency tables to determine association between ("before" and "after") protocols and CA outcome were generated. The likelihood of classifying CA outcome under the "Not fitting now and breathing regularly (verified)"-protocol 12 ALPHA-level 1 (12-A-1) and combined DELTA descriptor codes, was established. Odds ratios (OR) and p-values at significance level of 0.05 cut-off were used to determine any significant associations. RESULTS: For both datasets, the percentage of the emergency parameters increased with increasing determinant level from ALPHA to DELTA. The percentage of CA outcome in the 12-A-1 descriptor code in protocol version 11.2 was lower than that in version 10.4 (0.18% vs. 0.24%). Within protocol version 11.2, CA outcome was twice more likely in the combined DELTA descriptor codes when compared to other protocol 12 descriptor codes (OR(95%CI): 2.10(1.30, 1.40), p=0.002). CONCLUSIONS: The addition of the new assessment question for "breathing regularly" to the dispatch question sequence in the MPDS seizure protocol provides a valuable tool for identifying true cardiac arrest patients. Most of these cases appeared to be specifically captured by the new code 12 DELTA-level 3 (12-D-3): "Irregular Breathing".

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 System's (MPDS's) 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) and paramedic-determined high-acuity (blue-in [BI]/"lights and siren") findings. Odds ratios (ORs) with 95% confidence intervals (95% CIs) and p-values were used to assess the degree of associations between determinant codes and case outcomes (i.e., CA/BI). RESULTS: Statistically significant association between clinical dispatch determinant codes and case outcomes was observed in the "life status questionable" (LSQ; DELTA-1 [D-1]) and the "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) and for the BI outcome (OR [95% CI]: 0.47 [0.28, 0.77], p=0.003). The LSQ and all 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) and with 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 and CA cases. CONCLUSION: This dispatch protocol for unknown problems successfully differentiates dispatch coding of low-acuity and non-CA patients only when specific situational information such as the patient's 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 protocol's ability to differentiate high-acuity and CA patients. LSQ proved to be a better predictor of both CA and BI 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 and a 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 System's (MPDS) priority levels, and its more specific clinical determinant codes. METHODS: A retrospective descriptive study was done on a one year's 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 Fisher's 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.

Profile of emergency medical dispatch calls for breathing problems within the medical priority dispatch system protocol.

INTRODUCTION: A common chief complaint to emergency dispatch communication centers worldwide is "breathing problems". The chief complaint of breathing problems represents a wide spectrum of underlying diseases, patient conditions, and onset types. The current debate is on the potential ability of a dispatch protocol to safely and with high specificity, differentiate patients with minor or non-critical conditions from those conditions that pose risk to the patient and require advanced life support evaluation and care. This issue also has extended into the paramedic prehospital evaluation realm. OBJECTIVE: The objective of this study was to describe the distribution of Medical Priority Dispatch System (MPDS) codes representing the spectrum of clinical descriptions within the breathing problems chief complaint and their associated outcomes, at the scene and during transport, as determined by [UK] paramedics. METHODS: A retrospective, one-year study (September 2005 to August 2006) of a de-identified aggregate dataset from the London Ambulance Service (LAS) Trust was evaluated. A profile of the distribution of calls, incidents, patients, and outcomes (cardiac arrest [CA] and blue-in [BI] high acuity i.e., patients transported with lights and siren based on paramedic protocol) for the breathing problems chief complaint was evaluated. Odds ratios and 95% confidence intervals (CI) were used to quantify associations between the MPDS priority level's concurrent asthmatic conditions and outcomes. Two-sided Fisher's exact p-values were obtained to determine statistically significant associations, at a level of0.05. RESULTS: Sixteen percent (95,848/599,093) of all the patients were classified under the breathing problems chief complaint. Of these 95,848 patients, 367 (0.38%) were CA outcomes, and 7.82% (n = 7,493) were BI outcomes.The Cardiac Arrest Quotient (i.e., the number of CA cases as a percentage of the number of patients) for the ECHO priority level was 46 times higher than was that of non-ECHO priority levels: DELTA and CHARLIE (17.05% vs. 0.37%). Asthmatics were associated with CA outcome (OR(95%CI): 0.60(0.47,0.77), p <0.001), but not with BI outcome. CONCLUSIONS: The MPDS coding yielded a richer mix of severe outcomes in the higher priority levels.The Severe Respiratory Distress coding had the greatest number of patients and severe outcomes. Future studies that help refine the Severe Respiratory Distress code in the MPDS by more specific subgroups of patients would be beneficial.

Cardiac arrest predictability in seizure patients based on emergency medical dispatcher identification of previous seizure or epilepsy history.

OBJECTIVE: To determine predictability of at-scene cardiac arrest from a dispatch determined patient history of seizure or epilepsy ("E" history). DESIGN AND METHODS: A retrospective study of a 1 year dataset from the London Ambulance Service (LAS) National Health Service (NHS) Trust was undertaken. Each of the nine determinant codes on the Medical Priority Dispatch System (MPDS) seizure protocol [Heward A, Damiani M, Hartley-Sharpe C. Does the use of the Advanced Medical Priority Dispatch System affect cardiac arrest detection? Emerg Med J 2004;21:115-8.] was examined for the addition of the "E" suffix finding. The cardiac arrest predictability of cases with reported "E" history was compared to those without using a protocol process to detect the infrequent but predictable presence of seizures caused by anoxic cardiac arrest. RESULTS: Only protocol codes 12-A-1, 12-D-2, 12-D-3, and 12-D-4 demonstrated significant associations between outcomes and determinant codes (p=0.016, 0.007, <0.001, and 0.048, respectively). These codes showed reduced risk of predicting CA with the "E" suffix protocol determinant codes (RD (95% CI): -0.0025 (-0.0044, -0.0005), chi-square p=0.009; RD (95% CI): -0.0024 (-0.0042, -0.0005), p=0.005; RD (95% CI): -0.020 (-0.029, -0.011), p<0.001; RD (95% CI): -0.01 (-0.017, -0.005), and p=0.034, respectively). CONCLUSIONS: Knowing whether a seizure patient is an epileptic or has had previous seizures is of clinical value and relevant to dispatch. By improving the discernment of the seizure protocol regarding seizure associated with anoxic cardiac arrest predictability, this information may now be applied at the response level as well as to emergency medical dispatcher's (EMD) decisions to stay on the telephone to enhance the monitoring of these patients.

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.