title: Variability in surgical caseload and access to intensive care services.
abstract: BACKGROUND
  Variability in the demand for any service is a significant barrier to efficient distribution of limited resources. In health care, demand is often highly variable and access may be limited when peaks cannot be accommodated in a downsized care delivery system. Intensive care units may frequently present bottlenecks to patient flow, and saturation of these services limits a hospital's responsiveness to new emergencies.
  
  
  METHODS
  Over a 1-yr period, information was collected prospectively on all requests for admission to the intensive care unit of a large, urban children's hospital. Data included the nature of each request, as well as each patient's final disposition. The daily variability of requests was then analyzed and related to the unit's ability to accommodate new admissions.
  
  
  RESULTS
  Day-to-day demand for intensive care services was extremely variable. This variability was particularly high among patients undergoing scheduled surgical procedures, with variability of scheduled admissions exceeding that of emergencies. Peaks of demand were associated with diversion of patients both within the hospital (to off-service care sites) and to other institutions (ambulance diversions). Although emergency requests for admission outnumbered scheduled requests, diversion from the intensive care unit was better correlated with scheduled caseload (r = 0.542, P < 0.001) than with unscheduled volume (r = 0.255, P < 0.001). During the busiest periods, nearly 70% of all diversions were associated with variability in the scheduled caseload.
  
  
  CONCLUSIONS
  Variability in scheduled surgical caseload represents a potentially reducible source of stress on intensive care units in hospitals and throughout the healthcare delivery system generally. When uncontrolled, variability limits access to care and impairs overall responsiveness to emergencies.
authors.affiliation: Department of Anesthesia and the Multidisciplinary Intensive Care Unit, Children's Hospital Boston and Harvard Medical School, Massachusetts 02115, USA. mcmanus@tch.harvard.edu
authors.forename: Michael L
authors.initials: ML
authors.lastname: McManus
authors.forename: Michael C
authors.initials: MC
authors.lastname: Long
authors.forename: Abbot
authors.initials: A
authors.lastname: Cooper
authors.forename: James
authors.initials: J
authors.lastname: Mandell
authors.forename: Donald M
authors.initials: DM
authors.lastname: Berwick
authors.forename: Marcello
authors.initials: M
authors.lastname: Pagano
authors.forename: Eugene
authors.initials: E
authors.lastname: Litvak
mesh_terms: D001071:Appointments and Schedules; D003422:Critical Care / Q000458:organization & administration* / Q000706:statistics & numerical data; D004632:Emergency Medical Services; D006297:Health Services Accessibility; D006301:Health Services Needs and Demand; D006776:Hospitals, Pediatric; D007362:Intensive Care Units / Q000458:organization & administration* / Q000706:statistics & numerical data; D013514:Surgical Procedures, Operative / Q000706:statistics & numerical data*