The Changing Epidemiology of Mechanical Ventilation: A Population-Based Study

Abstract

The number of critical care beds in the United States has been increasing considerably, but it is unclear how these additional beds have been used. Mechanical ventilation for acute respiratory failure almost always demands ICU care and is likely to be a reliable indicator of critical care resource requirements on a population level. The objective of this study was to measure changes in the yearly incidence of mechanical ventilation in a statewide population. The North Carolina Hospital Discharge Database contains data on all discharges from nonfederal, nonpsychiatric hospitals in North Carolina. Authors extracted data on adult patients with International Classification of Diseases, 9th Revision, Clinical Modification procedure codes for mechanical ventilation from 1996 to 2002. The incidence of mechanical ventilation for adults grew from 284/100 000 population in 1996 to 314/100 000 in 2002, an increase of 11% ( P < .05). While patients aged >64 had the highest age-specific incidence of mechanical ventilation each year, the greatest increase in incidence occurred in younger age groups (19% increase for age 18-64 vs 4% increase for age >64). The mean Charlson score increased from 1.76 ± 1.73 to 1.89 ± 1.86 ( P < .001). Renal disease became more prevalent among patients requiring mechanical ventilation (17% of patients in 1996 vs 24% in 2002). Hospital charges adjusted for the medical consumer price index increased by 12%. The proportion of patients discharged to home declined from 45.4% to 34.4%, and discharges to nursing homes grew from 7.3% to 10.7%. The incidence of mechanical ventilation is increasing, and the increase is associated with a higher burden of comorbidities and fewer discharges to home.