Circadian pattern of intubation rates in ED patients with congestive heart failure.

PURPOSE

A previous study showed that pulmonary edema patients presenting between noon and 4 pm have the highest rates of myocardial infarction and death. We hypothesized that the highest intubation rates would also occur at these times.

BASIC PROCEDURES

We performed a retrospective cohort study of consecutive patients seen by emergency department physicians in 15 hospital emergency departments (1996-2003).

MAIN FINDINGS

Of 3.6 million visits in the database, 39,795 (1.1%) patients had congestive heart failure. We found statistically significant circadian variations in intubation rates. Patients arriving between midnight and 4 am had the highest intubation rates (4.1%), and those arriving between noon and 4 pm had the lowest (1.2%) (difference, 2.9%; 95% confidence interval, 2.4%-3.4%; P < .0001).

CONCLUSION

We found significant circadian variation in intubation rates, with a marked increase around midnight. Pathological mechanisms causing patients with congestive heart failure to require intubation may differ from those resulting in myocardial infarction or death.