Figure 1.

Weekly rates of hospitalization and rates of intensive care unit (ICU), mechanical ventilation (MV), and extracorporeal membrane oxygenation (ECMO) use among patients with influenza admitted to (A) hospital A, (B) hospital B, (C) hospital C, and (D) the combined three-hospital network of tertiary care hospitals during the 2013–2014 influenza season. Week numbers reflect Morbidity and Mortality Weekly Report (MMWR) numbering. Hospitalization rate is given as hospitalizations per week per 1,000 total admissions. ICU, mechanical ventilation, and ECMO rates are given as days of utilization per week per 1,000 total patient-days (influenza and noninfluenza patient-days).