CAEP/ACMU 2000 Scientific Abstracts: 18-21

CAEP Abstracts

CJEM 2001;2(3):169-187

018 Asthma Airway Management: The Prevalence of Ketamine Use as an Induction Agent for Rapid Sequence Intubation.
Worrall JC, Gurr DE, Walls RM, Pollack C. Brigham and Women's Hospital, Boston, Mass.

BACKGROUND: Intubation is sometimes required in severe, refractory cases of asthma. Rapid sequence intubation (RSI) is the airway management method of choice for patients with status asthmaticus in the emergency department. The Canadian Association of Emergency Physicians and many other experts recommend ketamine as the induction agent of choice because it has a rapid response time and is a good bronchodilator. OBJECTIVE: To determine the prevalence of ketamine use as an induction agent for RSI in the emergency department at teaching hospitals.
METHODS: Prospective observational study of 3,131 intubations recorded thus far in emergency departments at 22 teaching hospitals during the second phase (8/97­4/99) of the ongoing National Emergency Airway Registry (NEAR 97). Data included: method of airway management, indication, medications used, purpose of each.
RESULTS: Of the 3,131 intubations registered over this period, 99 listed "asthma" as an indication. Seventy-six of these patients were managed with RSI as the first choice of method. An additional three patients were managed with RSI after another method failed. Of these 79 patients, only two were intubated at institutions where ketamine was not available. One patient had a contraindication for ketamine (cerebrovascular accident). Twenty-eight of the remaining 76 patients (37%) were induced with ketamine (95% CI, 26% to 48%). CONCLUSIONS: We conclude that ketamine is not routinely used as an induction agent in the emergency intubation of patients in status asthmaticus.
Key words: intubation, rapid sequence induction, ketamine, asthma

019 The Epidemiology of Acute Asthma Presentations in Alberta.
Rowe BH, Yiannakoulias N, Voaklander D, Svenson L, Schopflocher D. University of Alberta and Alberta Health, Edmonton, Alta.

OBJECTIVES: Many asthmatic patients present to the emergency department (ED) and despite potentially serious consequences, much surveillance information is lost. This study examines the epidemiology of acute asthma presentations to the ED using a unique data set.
METHODS: All cases of acute asthma between the ages of 2­55 were eligible for inclusion. Data were derived from a cohort of all patients treated at Alberta EDs in 17 health regions over 1 year. Data were extracted from computerized abstracts coded similarly across all regional EDs using the Ambulatory Care Classification System (ACCS) database. Asthma was coded as 493.0­493.9 categories using ICD-9 coding by medical record nosologists in each hospital and represented the physician discharge diagnostic code. Descriptive statistics and age- and gender-adjusted presentation rates were calculated.
RESULTS: Acute asthma accounted for 35,743 (2.4%) of the more than 1.5 million annual visits to Alberta EDs. In addition, 40% of these patients required repeat ED visits for asthma in the same year. Males (18,209; 51%) and females were similarly represented, and patients <16 years old accounted for 17,752 (50%) of all cases. The highest proportion of visits (7,200; 20%) occurred in the 2­5 year age group. The adjusted ED presentation rates varied from 11/1000 ED visits (Capital Health) to 34/1000 ED visits (Lakeland). The lowest ED presentation rates occurred in the two largest urban areas (population >500,000). Most (32,414; 91%) patients were discharged from the ED, with little variation among age groups. However, 63 (<1%) were admitted to an ICU setting, and 2 died in the ED. CONCLUSIONS: Asthma is a common ED problem with marked variation among regions. These results demonstrate the utility of an the ACCS database, an ED population-based diagnostic registry. The registry functions as a surveillance and research tool to focus prospective disease-specific research. This tool has the potential to explore ecological factors associated with acute asthma.
Key words: asthma, epidemiology, registry, emergency department

020 A Description of Invasive Airway Management in a Major Canadian Emergency Medical Services System.
Richards CG, Petrie DA. Dalhousie University, Halifax, NS.

OBJECTIVES: To describe the effectiveness of EMS airway management and to identify cases of unsuccessful EMS intubation and describe how these cases were treated in the emergency department (ED).
METHODS: A retrospective review was undertaken of all adult patients requiring endotracheal intubation over a thirteen-month period (Jan. 1, 1999­Jan. 31, 2000) in a Canadian city with a population of greater than 350,000 people. The EMS quality audit (QA) database was reviewed for diagnosis, appropriateness of scene time, medications used, and number of attempts. For cases of unsuccessfully attempted EMS intubations in the final three months of the study, the patients' courses in the ED were reviewed using the National Emergency Airway Registry (NEAR) database in use at the hospital to track ED intubations. In these cases, additional data were gathered, including method and reason for intubation, and medications used.
RESULTS: EMS performed a total of 334 invasive airway management attempts on 256 adult patients (mean: 1.30 attempts/patient). The overall EMS successful intubation rate was 84.4%. Scene time was considered appropriate (that is, <15 minutes) in all cases. In the final three months of the study, at least half of the patients requiring ED intubation after an unsuccessful prehospital course were given neuromuscular blocking agents prior to successful intubation. CONCLUSIONS: Prehospital providers can intubate a high proportion of patients, but this rate can be improved. The use of pharmacologic adjuncts to facilitate the prehospital intubation of selected patients is a promising option that further evaluation.
Key words:emergency medical services, intubation

021 Can We Assess Asthma Severity Using Expiratory Capnography in a Pediatric Emergency Department?
Evered L, Ducharme F, Davis G, Pusic M. McGill University Health Centre, Montreal, Que.

OBJECTIVES: To determine the reproducibility and validity of expiratory capnography in the assessment of the severity of airway obstruction in asthmatic children.
METHODS: In a cross-sectional study of children presenting to the emergency department with acute asthma, 3 measurements were obtained at baseline: 1) respiratory resistance by forced oscillation (RFO); and 2) capnographs of 5 waveforms using a well-fitting mask and 3) capnographs of 5 waveforms using a mouth-piece. Reproducibility of the slopes of the alveolar plateau and Q angles was determined with the intra-class coefficient (ICC). The slope and the Q angle were correlated with airway resistance.
RESULTS: Twelve participants of mean age 9.8 years (range 7­14) had baseline resistance of 126% of predicted. The ICCs are reported in the table. Both the Q angle and the slope correlated poorly with RFO (Q angle: correlation coefficient (r) = 0.2; 95% Confidence Interval (CI): ­0.4, 0.7) (Slope: r = ­0.1; 95% CI: ­0.6, 0.5).
CONCLUSIONS: Despite high test-retest reproducibility, particularly using the mouthpiece, neither the Q angle nor slope were good indicators of the severity of airway obstruction, in this small sample of mild asthmatic children.
Key words: asthma, capnography