Population:
The medical (or combined medical/surgical) ICUs of six TIBDN hospitals will be selected to participate in this surveillance, representing community and academic hospitals (3 teaching hospitals. In hospitals with more than one intensive care unit, eligible ICUs will be those that admit patients from the community with acute respiratory illness (ie. surgical ICUs such as cardiovascular, neurosurgical will be excluded).
Procedures:
Influenza season will be defined by TIBDN as beginning on the Monday after the first week during which more than 5% of tests submitted to the Ontario public health laboratory for viral testing are positive for influenza. It will be defined as ending after 15 weeks, or when the proportion of tests positive for influenza has been below 5% for two consecutive weeks (whichever is longer).
During the influenza season, ICU physicians will request nasopharyngeal swabs for influenza testing for all admissions to the ICU who may have influenza: this will include patients with sepsis, pneumonia, exacerbations of chronic lung disease, and any other patients who, in the judgement of the attending physician, may have influenza. This will include patients admitted from the community, and those transferred from other units within the hospital, or other hospitals. Rapid testing, viral culture, and PCR will be performed on all specimens. Every effort will be made to have rapid testing available in <12 hours, and PCR results in less than 24 hrs (PCR on specimens obtained on Friday and Saturday may have a longer turn around time). Positive results will be telephoned to the ICU.
TIBDN study staff will visit each ICU every 24-72 hours, and record the number of admissions, the number tested for influenza, and the admitting diagnosis of all patients. Staff will also be available pre-season to assist in training staff in how to obtain NP swabs if necessary, will ensure that the appropriate swabs, viral transport media and requisitions are available, and will facilitate specimen transport to the laboratory when needed.
Any patients who have any positive test for influenza will be enrolled in the study (as per usual TIBDN surveillance, currently on-going. Demographic, medical and outcome data will be collected by chart review, and patient and physician interview.
At the end of the season, total patient days, and patient days for patients with a positive test for influenza will be recorded.
