CAEP/ACMU 2000 Scientific Abstracts: 37-39

CAEP Abstracts

CJEM 2001;2(3):169-187

037 The Vertical Access Interval: A Prospective Observational Comparison of the Impact of this Interval on the Emergency Medical Service Response Time for High-Rise Buildings vs. Houses.
Angelini MP, Peerbaye Y, Burgess R, Schwartz B, Morrison LJ. Division of Prehospital Care, Sunnybrook & Women's Health Sciences Centre, University of Toronto, Toronto Ambulance Service, Toronto, Ont.

OBJECTIVE: To compare the time interval between ambulance arrival at the scene to paramedic arrival at the patient ("vertical response" time) between high-rise buildings and houses; To define the barriers encountered by paramedics in responding to emergency calls in high-rise apartment buildings.
METHODS: A pilot study (42 cases) completed in December 1999 had promising results. This larger study was prospective, single blinded, and observational. An independent third-party observer collected time intervals on emergency medical service (EMS) calls. Potential barriers impeding EMS access to patients were recorded. RESULTS: The median vertical response interval for 118 calls was 96.5 seconds (interquartile range, 49.25 to 150.0 seconds) and represented 24% of the total EMS response time. Vertical response time for emergency calls originating from apartment buildings (n = 40) were significantly prolonged in comparison to those from houses (n = 24) (median 142.5 sec vs. 68 sec, p < 0.05). The median vertical response interval for apartment buildings where EMS calls originated <2 floors above ground was 131 sec (96­185 sec). The most common barriers encountered were the need for an entry code to enter the building (25/40, 62.5%) and the elevator was too small to fit stretcher in prone position (19/40, 47.5%). In potentially life-threatening calls (delta priority), median vertical response interval times in apartment buildings (n = 20) were significantly longer than in houses (n = 13) (127 sec vs. 63 sec, p < 0.05). CONCLUSIONS: The vertical response interval represented a significant component of the total EMS response time and was longer for calls originating in apartment buildings. The increased response time due to vertical access significantly prolonged the time to treatment in the highest priority calls where delay has been shown to effect outcome.
Key words: emergency medical services, response time

038 Conditions Under Which EMS Crews Do Not Resuscitate Out-of-Hospital Cardiac Arrest Victims.
Nagendran J, Yoon PW, Steiner IP. University of Alberta, Edmonton, Alta.

OBJECTIVES: TMuch of the research on out-of-hospital cardiac arrest (OHCA) victims focuses on the patient population that received resuscitative efforts. The objective of this study was to determine the circumstances under which Emergency Medical Service (EMS) crews elected not to initiate resuscitative efforts.
METHODS: Over a 12-month period, EMS records of all OHCA victims were examined. Analysis and comparison were performed on the resuscitation and the non-resuscitation (NR) groups. The study area was a large Canadian city (population: 800,000) with a single, centralized EMS system which permits declaration of death in the field and respects standardized do-not-resuscitate (DNR) orders. RESULTS: Of the 792 OHCA cases studied, no resuscitative efforts were documented on 371 (46%) patients for whom an ambulance was initially dispatched. For the NR group, the initial event was less often witnessed (6% vs. 53%; p < 0.05) and bystander CPR was less often provided (4% vs. 44%; p < 0.05) to victims. The average age of the NR group was 61 years and the male-to-female ratio was 1.8:1; this was not significantly different from the resuscitation group profile (mean age 59 years and male-to-female ratio of 2.2:1). Cardiac monitors were applied to 95 (26%) NR patients, and the most common rhythm was asystole (98%). Documented reasons for NR status were rigor mortis in 244 cases (66%), lividity in 184 (50%), and signs of decomposition in 16 (4%). Only 17 (5%) patients had a DNR order. 45 NR patients (12.1%) had no cardiac monitor applied and no documentation of rigor mortis, lividity, or decomposition. CONCLUSIONS: A large proportion of OHCA patients in this urban centre do not undergo resuscitative interventions. The probability of falling into this group of patients is increased when the initial event is not witnessed and if bystander CPR is not provided. The application of a cardiac monitor was not consistent for all OHCA patients. Further research in this area would be enhanced with the use of standardized protocols for the reporting of OHCA victims.
Key words: emergency medical services, resuscitation

039 Cost-Effective Adenosine Dosing in the Emergency Department.
Sedran RJ, Abu-Laban RB. Vancouver General Hospital, Vancouver, BC.

OBJECTIVES: Current guidelines for the treatment of PSVT with adenosine call for a 6-mg IV dose followed by 12 mg if required. Frequently 6 mg is ineffective thus many patients receive a total of 18 mg. As there is no safety benefit from a lower starting dose, this calls into question the cost-effectiveness of the sequential dosing strategy. We sought to determine whether a single 12-mg dose in ED patients with PSVT would result in cost savings. A threshold minimum of 50% conversion with 6 mg was established a priori as the point at which cost would favor current guidelines.
METHODS: The charts for all ED patients at a tertiary hospital coded with a discharge diagnosis of atrial dysrhythmia from June 1997 to June 1999 were retrospectively reviewed using explicit criteria. Information was collected on demographics, case specifics, adenosine dosing and conversion success. The results were analyzed using Stata (Version 5.0, Macintosh).
RESULTS: 251 charts were reviewed and 85 cases of PSVT were identified, 51 of which received adenosine: 27 patients converted with 6 mg (52.9%; 95% CI, 38.5%­67.1%) and an additional 12 patients converted with 12 mg (23.5%; 95% CI, 12.8%­37.5%). In total, 39 patients converted from PSVT with adenosine (76.5%; 95% CI, 62.5%­87.2%).
CONCLUSIONS: The results marginally favor maintaining the current sequential 6-mg/12-mg adenosine dosing strategy. Sample size projections indicate that a study of up to 1,200 cases could be required to narrow the confidence intervals sufficiently to be certain which side of the 50% threshold the 6-mg conversion rate from adenosine actually lies.
Key words: supraventricular tachycardia, adenosine