Olof Wall1, Lars Ehrenberg2, Eva Joelsson-Alm3, Johan Mårtensson4, Rinaldo Bellomo5, Christer Svensén3, Maria Cronhjort3. 1. Department of Clinical Science and Education, Karolinska Institutet, Södersjukhuset, Stockholm, Sweden. olof.wall@sll.se. 2. Department of Anaesthesiology and Intensive Care, Södersjukhuset, Stockholm, Sweden. 3. Department of Clinical Science and Education, Karolinska Institutet, Södersjukhuset, Stockholm, Sweden. 4. Department of Physiology and Pharmacology, Section of Anaesthesia and Intensive Care Medicine, Karolinska Institutet, Stockholm, Sweden. 5. Department of Intensive Care, Austin Hospital, Melbourne, Vic, Australia.
Abstract
OBJECTIVE: To test the hypothesis that changes in cardiac index and mean arterial pressure (MAP) during and after a fluid bolus (FB) are altered by fluid temperature. DESIGN: Randomised, controlled, crossover trial. SETTING: Research laboratory at Swedish teaching hospital. PARTICIPANTS: Twenty-one healthy adult volunteers. INTERVENTIONS: Subjects were randomly allocated to 500 mL of Ringer's acetate at room temperature (22°C; cold) or body temperature (38°C; warm). MAIN OUTCOME MEASURES: For 2 hours after starting the FB, we measured cardiac index, MAP, systolic blood pressure, diastolic blood pressure and pulse rate (PR) continuously. We recorded temperature and O2 saturation every 5 minutes during infusion and every 15 minutes thereafter. In a second session, volunteers crossed over. RESULTS: During the first 15 minutes, mean cardiac index increased more with warm FB (0.09 L/min/m2 [95% CI, 0.06-0.11] v 0.03 L/min/m2 [95% CI, 0.01-0.06]; P < 0.001). This effect was mediated by a significant difference in mean PR (+0.80 beats/min [95% CI, 0.47-1.13] v -1.33 beats/ min [95% CI, -1.66 to -1.01]; P < 0.010). In contrast, MAP increased more with cold FB (4.02 mmHg [95% CI, 3.63-4.41] v 0.60 mmHg [95% CI, 0.26-0.95]; P < 0.001). Cardiac index and MAP returned to baseline after a median of 45.3 min (interquartile range [IQR], 10.7-60.7 min) and 27.7 min (IQR, 5.3-105.0 min), respectively, after cold FB, and by 15.8 min (IQR, 3.8-64.3 min) and 22.7 min (IQR, 3.3-105.0 min), respectively, after warm FB. CONCLUSION: Intravenous FB at body temperature leads to a greater increase in cardiac index compared with room temperature, while the reverse applies to MAP. These findings imply that in healthy volunteers, when a room temperature FB is given, the temperature of the fluid rather than its volume accounts for most of the MAP increase. TRIAL REGISTRATION: EudraCT no. 2016-002548-18 and Clinicaltrials.gov NCT03209271.
RCT Entities:
OBJECTIVE: To test the hypothesis that changes in cardiac index and mean arterial pressure (MAP) during and after a fluid bolus (FB) are altered by fluid temperature. DESIGN: Randomised, controlled, crossover trial. SETTING: Research laboratory at Swedish teaching hospital. PARTICIPANTS: Twenty-one healthy adult volunteers. INTERVENTIONS: Subjects were randomly allocated to 500 mL of Ringer's acetate at room temperature (22°C; cold) or body temperature (38°C; warm). MAIN OUTCOME MEASURES: For 2 hours after starting the FB, we measured cardiac index, MAP, systolic blood pressure, diastolic blood pressure and pulse rate (PR) continuously. We recorded temperature and O2 saturation every 5 minutes during infusion and every 15 minutes thereafter. In a second session, volunteers crossed over. RESULTS: During the first 15 minutes, mean cardiac index increased more with warm FB (0.09 L/min/m2 [95% CI, 0.06-0.11] v 0.03 L/min/m2 [95% CI, 0.01-0.06]; P < 0.001). This effect was mediated by a significant difference in mean PR (+0.80 beats/min [95% CI, 0.47-1.13] v -1.33 beats/ min [95% CI, -1.66 to -1.01]; P < 0.010). In contrast, MAP increased more with cold FB (4.02 mmHg [95% CI, 3.63-4.41] v 0.60 mmHg [95% CI, 0.26-0.95]; P < 0.001). Cardiac index and MAP returned to baseline after a median of 45.3 min (interquartile range [IQR], 10.7-60.7 min) and 27.7 min (IQR, 5.3-105.0 min), respectively, after cold FB, and by 15.8 min (IQR, 3.8-64.3 min) and 22.7 min (IQR, 3.3-105.0 min), respectively, after warm FB. CONCLUSION: Intravenous FB at body temperature leads to a greater increase in cardiac index compared with room temperature, while the reverse applies to MAP. These findings imply that in healthy volunteers, when a room temperature FB is given, the temperature of the fluid rather than its volume accounts for most of the MAP increase. TRIAL REGISTRATION: EudraCT no. 2016-002548-18 and Clinicaltrials.gov NCT03209271.