To develop an operational definition and a parsimonious list of postulated determinants for urban emergency department (ED) overcrowding.

A panel was formed from clinical and administrative experts in pre-hospital, ED and hospital domains. Key studies and reports were reviewed in advance by panel members, an experienced health services researcher facilitated the panel’s discussions, and a formal content analysis of audiotaped recordings was conducted.

The panel considered community, patient, ED and hospital determinants of overcrowding. Of 46 factors postulated in the literature, 21 were not retained by the experts as potentially important determinants of overcrowding. Factors not retained included access to primary care services and seasonal influenza outbreaks. Key determinants retained included admitted patients awaiting beds and patient characteristics. Ambulance diversion was considered to be an appropriate operational definition and proxy measure of ED overcrowding.

These results help to clarify the conceptual framework around ED overcrowding, and may provide a guide for future research. The relative importance of the determinants must be assessed by prospective studies.

Aeromedical transport in northern areas may be associated with hypothermia. The objective of this study was to determine whether significant hypothermia (core temperature <35ºC) occurs in severely injured or ill intubated patients during transport by rotary wing aircraft.

In this prospective cohort study, all intubated patients over 16 years of age who were transported by rotary wing aircraft from rural hospitals or trauma scenes in northern Alberta to regional hospitals in Edmonton were eligible for study. Esophageal thermometers were used to measure core temperature at 10-minute intervals during transport.

Of 133 potentially eligible patients, 116 were enrolled; 69 (59%) had esophageal thermometers inserted, and 47 (41%) had other temperature measurements. Severe hypothermia occurred in only 1% to 2% of cases, but 28% to 39% of patients met criteria for mild hypothermia prior to transport. Core temperatures did not fall during transport, despite the fact that warming techniques were documented in only 38% of cases.

During brief (<225 km) rotary wing aeromedical transport of severely injured or ill patients, significant hypothermia is uncommon and body temperature is generally well maintained with the use of simple passive measures. These findings do not justify recommendations for more aggressive core temperature monitoring during this type of aeromedical transport.

In 2000 the Ontario Minister of Health and Long-Term Care announced a universal influenza immunization program for Ontario, Canada. The 2 objectives of this $38-million program were to decrease seasonal impact of influenza on emergency department (ED) visits and to decrease the number and severity of influenza cases. This paper examines the correlation between population influenza rates and ED visits in 5 tertiary care hospitals in Ontario over a 5-year period (1996–2001).

In this retrospective, observational study, we determined the total number of ED visits during the study period, by month, at 5 tertiary care hospitals in 3 Ontario cities Kingston, London and Ottawa). Detailed ED diagnoses were captured for Kingston, and provincial and national population-based influenza rates were obtained from Health Canada for the 5-year study period. Correlation and regression analyses were used to determine the relationship of influenza rates and ED volumes. “Influenza season” is defined in this study as November 1st to March 31st of each year.

There was no significant correlation between influenza rates and ED volumes, with Pearson correlation coefficients (r) of 0.22 (p = 0.72), 0.33 (p = 0.59) and 0.27 (p = 0.66) at the Kingston, London and Ottawa study sites, respectively. Data from the Kingston hospitals showed that, during influenza season, acute respiratory diagnoses accounted for only 4.4% of ED visits and influenza for only 0.34% of visits. Multiple linear regression analysis showed that the ED diagnosis of influenza was not significantly related to ED volume. During the influenza season after the universal immunization campaign, ED visits increased at all sites.

Based on this study, a universal influenza immunization campaign is unlikely to affect ED volume.