Rapid response calls are fewer in the middle of the night, mortality spikes at 7 AM

That means rapid response systems save lives, right?

No, not in my reading of the study. Here’s a summary of the findings:

Objectives: Decreased staffing at nighttime is associated with worse outcomes in hospitalized patients. Rapid response teams were developed to decrease preventable harm by providing additional critical care resources to patients with clinical deterioration. We sought to determine whether rapid response team call frequency suffers from decreased utilization at night and how this is associated with patient outcomes.

Design: Retrospective analysis of a prospectively collected registry database.

Setting: National registry database of inpatient rapid response team calls.

Patients: Index rapid response team calls occurring on the general wards in the American Heart Association Get With The Guidelines-Medical Emergency Team database between 2005 and 2015 were analyzed.

Interventions: None.

Measurements and Main Results: The primary outcome was inhospital mortality. Patient and event characteristics between the hours with the highest and lowest mortality were compared, and multivariable models adjusting for patient characteristics were fit. A total of 282,710 rapid response team calls from 274 hospitals were included. The lowest frequency of calls occurred in the consecutive 1 AM to 6:59 AM period, with 266 of 274 (97%) hospitals having lower than expected call volumes during those hours. Mortality was highest during the 7 AM hour and lowest during the noon hour (18.8% vs 13.8%; adjusted odds ratio, 1.41 [1.31-1.52]; p less than 0.001). Compared with calls at the noon hour, those during the 7 AM hour had more deranged vital signs, were more likely to have a respiratory trigger, and were more likely to have greater than two simultaneous triggers.

Conclusions: Rapid response team activation is less frequent during the early morning and is followed by a spike in mortality in the 7 AM hour. These findings suggest that failure to rescue deteriorating patients is more common overnight. Strategies aimed at improving rapid response team utilization during these vulnerable hours may improve patient outcomes.

I have no data but my strong subjective impression is that this diurnal pattern existed long before anybody thought up the idea of rapid response teams. Hospital resources are slim at night and are most readily available mid day. 7 AM is shift change in most hospitals. There are a lot of confounders here.