Comparison between two methods for cardiac output measurement in propofol-anesthetized dogs: thermodilution and Doppler.
OBJECTIVE
To compare cardiac output (CO) measured by Doppler echocardiography and thermodilution techniques in spontaneously breathing dogs during continuous infusion of propofol. To do so, CO was obtained using the thermodilution method (CO(TD)) and Doppler evaluation of pulmonary flow (CO(DP)) and aortic flow (CO(DA)).


METHODS
Prospective cohort study.


METHODS
Eight adult dogs weighing 8.3 +/- 2.0 kg.


METHODS
Propofol was used for induction (7.5 +/- 1.9 mg kg(-1) IV) followed by a continuous rate infusion at 0.7 mg kg(-1) minute(-1). The animals were positioned in left lateral recumbency on an echocardiography table that allowed for positioning of the transducer at the 3rd and 5th intercostal spaces of the left hemithorax for Doppler evaluation of pulmonary and aortic valves, respectively. CO(DP) and CO(DA) were calculated from pulmonary and aortic velocity spectra, respectively. A pulmonary artery catheter was inserted via the jugular vein and positioned inside the lumen of the pulmonary artery in order to evaluate CO(TD). The first measurement of CO(TD), CO(DP) and CO(DA) was performed 30 minutes after beginning continuous infusion (T0) and then at 15-minute intervals (T15, T30, T45 and T60). Numeric data were submitted to two-way anova for repeated measurements, Pearson's correlation coefficient and Bland & Altman analysis. Data are presented as mean +/- SD.


RESULTS
At T0, CO(TD) was lower than CO(DA). CO(DA) was higher than CO(TD) and CO(DP) at T30, T45 and T60. The difference between the CO(TD) and CO(DP), when all data were included, was -0.04 +/- 0.22 L minute(-1) and Pearson's correlation coefficient (r) was 0.86. The difference between the CO(TD) and CO(DA) was -0.87 +/- 0.54 L minute(-1) and r = 0.69. For CO(TD) and CO(DP), the difference was -0.82 +/- 0.59 L minute(-1) and r = 0.61.


CONCLUSIONS
Doppler evaluation of pulmonary flow was a clinically acceptable method for assessing the CO in propofol-anesthetized dogs.
Lopes
Patricia Cristina Ferro
PC
Department of Veterinary Medicine and Surgery, Veterinary Surgery Postgraduate Program, College of Agricultural and Veterinary Sciences, Universidade Estadual Paulista, Jaboticabal, São Paulo, Brazil.
Sousa
Marlos Gonçalves
MG
Camacho
Aparecido Antonio
AA
Carareto
Roberta
R
Nishimori
Celina T D
CT
Santos
Paulo S P
PS
Nunes
Newton
N
D000771:Anesthesia, Intravenous / Q000662:veterinary; D018686:Anesthetics, Intravenous; D000818:Animals; D001011:Aorta / Q000000981:diagnostic imaging; D002302:Cardiac Output / Q000502:physiology*; D004285:Dogs / Q000502:physiology*; D015150:Echocardiography, Doppler / Q000662:veterinary*; D005260:Female; D008297:Male; D015742:Propofol; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D013815:Thermodilution / Q000662:veterinary*
D018686:Anesthetics, Intravenous; D015742:Propofol