Norwegian Index for Emergency Medical Assistance. Studies on the Use and Precision of the Emergency Medical Dispatch Guidelines in Norway
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The main aim of this thesis was to initiate a validation process of the Norwegian Index for Emergency Medical Assistance (Index). Before we could do that, however, we had to explore to which extent the Index actually is used by the Norwegian emergency medical communication centres (EMCCs).
The Index is the emergency medical dispatch guidelines used by operators at EMCC when they receive and handle calls at the emergency medical line. In Norway, 113 is the specific toll-free line for medical emergencies. The Index was developed in 1994, and is now available in the 3rd edition (2009). All EMCCs and a majority of the local emergency medical communication centres (LEMCs) in Norway claim to use the Index upon receipt of 113 calls. In 2010, knowledge on the epidemiology of 113 calls was non-existing.
Criteria-based dispatch guidelines are designed to be used in close cooperation with experienced health educated EMCC operators, and the operators are intended to bring their knowledge, experience and skill into the assessment process. This has complicated past research, as it is difficult to determine whether the determined criteria code or dispatched response is due to the guidelines themselves, the operator’s own assessment or a combination of both. In addition, the Index is still paper-based, so that its use remains unable to track.
After the initial mapping of the place, situation and the patient’s vital functions found on the start page, the rest of the Index criteria cards are symptom-based. This makes it challenging to compare specific Index criteria codes with specific discharge diagnoses from hospitals, as a measure on Index validity. Criteria card “27 Altered levels of consciousness – paralysis”, specifically the criteria codes A. 27.03–06, was considered comparable to the diagnosis of stroke, including intracerebral haemorrhage, acute ischemic stroke and transient ischemic attack.
The objectives of the individual studies were to gain more knowledge about:
- The 113 epidemiology in Norway
- Use of the Index by the EMCCs
- The Index’s validity in identification and prediction of stroke
Study 1 was a cross-sectional survey of all 113-enquiries to the 19 EMCCs during a 72-hour period in August 2011. The final material consisted of 2 298 printouts from the electronic EMCC records, Emergency medical information system (AMIS), and contained information about time, caller, patient, Index criteria code, response and resources allocation. The national mean 113 contact rate was 56/1 000 population per year, but the variation among the different EMCCs was from 33 to 114. The acute contact rate was 21/1 000 per year, with a variation of 5 to 31. Urgency distribution showed 37% acute, 34% urgent and 27% non-urgent contacts. The most frequently used Index criteria card was “06 Unclear problem”, which was used in 20% of the contacts, with a variation of 10 to 42% among the EMCCs.
Study 2 was a national questionnaire study to all EMCC operators, to explore selfreported use of the Index. The questionnaire contained questions about use of the Index, education, EMCC experience, and training in, and repetition on the use of the Index at their workplace. Response rate was 63.4%, and the typical operator among the respondents was a female registered nurse with six years of EMCC experience, who worked in rotation with either the emergency department or ambulance. Mean self-reported use of the Index was calculated to be 3.95, corresponding to the response format 4 = “often, > 75%”. Rotation with ambulance reduced use of the Index, while experienced focus on use of the Index at workplace increased the use. The operators checked whether the patient was conscious or not in 93% of the calls, but claimed to use the start page in only 47%. Availability of the electronic AMIS was the most frequent stated reason for not using the start page or the Index as a whole.
Study 3 was a review of the audio logs from the same time period as Study 1, to assess use of the Index in an objective manner, and then see if the guideline adherence affected the emergency medical dispatch (EMD) response interval. Seven EMCCs participated, with a total of 299 randomized calls, 174 acute and 125 urgent. The EMCC selection was strategic, based on variation in size, geographical location, various health trusts, and the EMCCs’ mean self-reported use of the Index from Study 2. The listening form measured whether and how fast the operator got various indicators on use of the Index confirmed. The indicators “location”, “consciousness” and “criteria compliance” were combined in an overall guideline adherence variable, where 0 indicated no guideline adherence and 3 the maximum guideline adherence. Mean guideline adherence was 2.41, equivalent to 80% of the maximum score. EMD response interval increased with decreased guideline adherence score.
Study 4 was a retrospective registry study comparing patients with EMCC stroke suspect criteria codes and patients with hospital stroke diagnoses. The material consisted of AMIS-printouts from Bergen EMCC, and patient data from Haukeland University Hospital, Haraldsplass Diaconal Hospital and Voss Hospital. Less than half of the confirmed stroke patients’ initial EMCC contact was via 113 line, 52% of the patients were in contact with the primary health care services first. By combining patient data from the stroke database at Haukeland University Hospital and the 113- data from Bergen EMCC, we calculated sensitivity for stroke identification at EMCC contact of 57.9%, specificity of 99.1%, positive predictive value (PPV) of 45.7% and negative predictive value (NPV) of 99.4%. Stroke patients whom initial EMCC contact was via the 113 line had a higher proportion of acute responses and stroke suspect criteria codes. Although the majority of stroke patients who came in contact with the EMCC via primary health care services did not receive stroke suspect criteria codes, 85% of these calls had free-text notes addressing stroke suspicion.
- The national mean 113 contact rate was 56/1 000 a year, but the individual contact rates for the different EMCCs varied between 33 and 114. The urgency distribution was 37% acute, 34% urgent and 27% non-urgent contacts. Index criteria card “06 Unclear problem” was the most frequently used, used in between 10 and 42% of the contacts among the different EMCCs.
- Self-reported use of the Index by the operators was > 75%. Working in rotation, with shifts at both the EMCC and the ambulance service, was associated with reduced use of the Index, while focus on use of the Index at the EMCC increased use. AMIS was the most frequent stated reason for not using the Index.
- Measured mean guideline adherence was 80% of the maximum score. Low guideline adherence score correlated with longer EMD response interval.
- The Index’s ability to identify or predict stroke patients is modest, with a sensitivity of 57.9%, specificity of 99.1%, PPV of 45.7% and NPV of 99.4%. More than half of the stroke patients initially contacted primary health care services instead of 113.