Thermodilution right ventricular ejection fraction measurements: room temperature versus cold temperature injectate.
OBJECTIVE
To compare thermodilution right ventricular ejection fraction measurements using 10 mL room temperature injectate vs. 10 mL cold temperature injectate.


METHODS
Prospective, clinical study.


METHODS
Adult surgical intensive care unit (ICU) in a university hospital.


METHODS
Sixty adult surgical ICU patients requiring hemodynamic monitoring by a pulmonary artery catheter.


METHODS
Patients were in a supine position with the bed flat during thermodilution measurements. Four 10 mL room temperature injections were alternated with four 10 mL cold temperature injections.


RESULTS
One hundred eleven paired thermodilution right ventricular ejection fraction measurements were made in patients during a "steady state." There were no restrictions regarding body temperature, cardiac index, heart rate or rhythm. Injectate temperature was measured by an in-line temperature probe. Injections were synchronized with end-expiration of mechanical ventilator breaths. The first injection was deleted from each temperature group. Reproducibility of individual right ventricular ejection fraction measurements was assessed by calculating the mean variation of triplicate measurements in each temperature group. Mean values of room temperature measurements were compared with cold temperature measurements by Student's t-test. Linear regression analysis, bias, and precision were also calculated. There was no significant difference (p = .752) between mean right ventricular ejection fraction measurements determined with room temperature (23.9 +/- 1 degrees C) vs. cold temperature (8.0 +/- 1.1 degrees C) injectate. There was a high degree of correlation between measurements (r2 = .876, p < .001). The bias of room temperature measurements compared with cold temperature was -0.39% and the precision was +/- 3.3%. The mean variation between individual measurements in all room temperature and cold temperature right ventricular ejection fraction measurements was 9.7% and 8.0%, respectively. There was no significant difference and there was a high degree of correlation in mean right ventricular ejection fraction measurements when data were grouped according to body temperature, heart rate, cardiac index, right ventricular ejection fraction, central venous pressure, pulmonary vascular resistance index, right ventricular end-diastolic volume index, or right ventricular stroke work index.


CONCLUSIONS
The results suggest that room temperature injectate may be used for right ventricular ejection fraction measurements in critically ill adult surgical patients. Utilizing room temperature injectate for right ventricular ejection fraction measurements may save time and costs in the critical care unit.
Surgical Critical Care Service, Vanderbilt University, Nashville, TN 37232-2100.
K
K
Safcsak
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LD
Nelson
D000328:Adult; D000368:Aged; D003080:Cold Temperature; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D013318:Stroke Volume; D013696:Temperature; D013815:Thermodilution / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D016278:Ventricular Function, Right