title: Effects of iced and room temperature injectate on cardiac output measurements in critically ill patients with low and high cardiac outputs.
abstract: OBJECTIVE
  To determine the effect of injectate temperature (iced or room temperature) on cardiac output values in critically ill adults with low and high cardiac outputs.
  
  
  METHODS
  Quasi-experimental.
  
  
  METHODS
  Two multidisciplinary intensive care units in two large, metropolitan, private, nonprofit hospitals in Texas.
  
  
  METHODS
  A convenience sample of 21 critically ill men and women who averaged 61 years of age (range 31 to 82 years) and whose most recent cardiac output measured with room temperature injectate was low (< or = 3.5 L/min) or high (> or = 8.0 L/min).
  
  
  METHODS
  Iced injectate and room temperature injectate (randomly ordered) were used to measure cardiac output in each subject.
  
  
  METHODS
  Cardiac output value with iced injectate versus cardiac output value with room temperature injectate.
  
  
  RESULTS
  We found significant differences between cardiac output measurements with room temperature and those with iced injectate in eleven critically ill patients with low cardiac outputs (< or = 3.5 L/min) and in ten critically ill patients with high cardiac outputs (> or = 8.0 L/min). In the low cardiac output group, cardiac outputs using room temperature injectate averaged 0.37 L/min (range 0.1 to 1.10 L/min) higher than cardiac outputs using iced injectate (p = 0.001). In the high cardiac output group, measurements with room temperature injectate averaged 1.17 L/min L/min (range 0.3 to 3.0 L/min) higher than cardiac outputs with iced injectate (p = 0.005). Percent differences between room temperature and iced injectate values averaged 13% (range 3% to 27%) in patients with low cardiac outputs and 11% (range 3% to 29%) in patients with high cardiac outputs. Seven (77%) of the patients in the low cardiac output group and four (40%) of the patients in the high cardiac group had a 10% or greater difference--which many clinicians describe as a clinically significant difference--between room temperature and iced injectate cardiac output values.
  
  
  CONCLUSIONS
  Although research is clearly needed to substantiate these findings, we suggest that nurses use iced injectate in patients with low and high cardiac outputs (< or = 3.5 L/min or > or = 8.0 L/min) to ensure accurate measurement of cardiac output.
authors.affiliation: Saint Joseph Hospital, Fort Worth, Texas.
authors.forename: D C
authors.initials: DC
authors.lastname: Wallace
authors.forename: E H
authors.initials: EH
authors.lastname: Winslow
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002302:Cardiac Output; D015400:Clinical Nursing Research; D016638:Critical Illness; D003936:Diagnosis, Computer-Assisted; D005260:Female; D006801:Humans; D007267:Injections / Q000451:nursing / Q000592:standards*; D008297:Male; D008875:Middle Aged; D013696:Temperature; D013815:Thermodilution / Q000379:methods / Q000451:nursing / Q000592:standards*