title: Nontraumatic out-of-hospital hypotension predicts inhospital mortality.
abstract: OBJECTIVE
  Out-of-hospital hypotension may signify need for intensive resuscitation and rapid diagnosis on emergency department (ED) arrival. We hypothesized that nontraumatic out-of-hospital hypotension confers risk of inhospital mortality.
  
  
  METHODS
  This was a multicenter study of ambulance-transported, nontrauma, non-cardiopulmonary resuscitation patients conducted at 2 venues: (1) a cross-sectional risk assessment study of high-priority medical transports at a US metropolitan county; and (2) a Canadian prospective multicenter cohort study of patients with respiratory distress. Data at both venues were extracted from prospectively recorded, standardized run sheets by either a physician or a paramedic. Data extraction and analysis at each venue were conducted independently. Exposures to hypotension were defined as age older than 17 years old, systolic blood pressure less than 100 mm Hg during transport, and 1 or more of 10 predefined symptoms of circulatory insufficiency. Nonexposures to hypotension had the same definition as exposures, except the systolic blood pressure had to be more than 100 mm Hg during the entire out-of-hospital transport. The main outcome variable was inhospital mortality.
  
  
  RESULTS
  At venue 1, of 3,128 transports, 395 (13%) exposures and 395 nonexposures were identified. Inhospital mortality of exposures was 26% versus 8% for nonexposures (adjusted odds ratio [OR] 4.6; 95% confidence interval [CI] 2.0 to 5.9). At venue 2, of 7,679 transports, 532 exposures (7%) and 7,147 nonexposures were identified. Out-of-hospital exposure to hypotension conferred a mortality rate of 32% versus 11% for nonexposures (OR 3.0; 95% CI 2.4 to 3.7), representing a sensitivity of 18% and a specificity of 95%.
  
  
  CONCLUSIONS
  The inhospital mortality rate after out-of-hospital, nontraumatic hypotension is high and reproducible. Future research should focus on ED clinical protocols to ensure appropriate resuscitation and investigation of etiology of out-of-hospital hypotension.
authors.affiliation: Department of Emergency Medicine, Carolinas Medical Center, Charlotte, NC, USA.
authors.forename: Alan E
authors.initials: AE
authors.lastname: Jones
authors.forename: Ian G
authors.initials: IG
authors.lastname: Stiell
authors.forename: Lisa P
authors.initials: LP
authors.lastname: Nesbitt
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Spaite
authors.forename: Nael
authors.initials: N
authors.lastname: Hasan
authors.forename: Brian A
authors.initials: BA
authors.lastname: Watts
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Kline
mesh_terms: D000368:Aged; D000552:Ambulances / Q000706:statistics & numerical data*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D042241:Early Diagnosis; D004632:Emergency Medical Services / Q000458:organization & administration / Q000706:statistics & numerical data*; D004636:Emergency Service, Hospital / Q000458:organization & administration*; D005260:Female; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007022:Hypotension / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy; D007362:Intensive Care Units / Q000458:organization & administration; D008020:Life Support Care / Q000458:organization & administration / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009657:North Carolina; D009864:Ontario; D010360:Patient Transfer / Q000458:organization & administration; D011446:Prospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D015996:Survival Rate; D014187:Transportation of Patients / Q000458:organization & administration