Comparison of noninvasive cardiac output measured by use of partial carbon dioxide rebreathing or the lithium dilution method in anesthetized foals.
OBJECTIVE
To compare cardiac output (CO) measured by use of the partial carbon dioxide rebreathing method (NICO) or lithium dilution method (LiDCO) in anesthetized foals.


METHODS
Data reported in 2 other studies for 18 neonatal foals that weighed 32 to 61 kg.


METHODS
Foals were anesthetized and instrumented to measure direct blood pressure, heart rate, arterial blood gases, end-tidal isoflurane and carbon dioxide concentrations, and CO. Various COs were achieved by administration of dobutamine, norepinephrine, vasopressin, phenylephrine, and isoflurane to allow comparisons between LiDCO and NICO methods. Measurements were obtained in duplicate or triplicate. We allowed 2 minutes between measurements for LiDCO and 3 minutes for NICO after achieving a stable hemodynamic plane for at least 10 to 15 minutes at each CO.


RESULTS
217 comparisons were made. Correlation (r = 0.77) was good between the 2 methods for all determinations. Mean +/- SD measurements of cardiac index for all comparisons with the LiDCO and NICO methods were 138 +/- 62 mL/kg/min (range, 40 to 381 mL/kg/min) and 154 +/- 55 mL/kg/min (range, 54 to 358 mL/kg/min), respectively. Mean difference (bias) between LiDCO and NICO measurements was -17.3 mL/kg/min with a precision (1.96 x SD) of 114 mL/kg/min (range, -131.3 to 96.7). Mean of the differences of LiDCO and NICO measurements was 4.37 + (0.87 x NICO value).


CONCLUSIONS
The NICO method is a viable, noninvasive method for determination of CO in neonatal foals with normal respiratory function. It compares well with the more invasive LiDCO method.
Valverde
Alexander
A
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
Giguère
Steeve
S
Morey
Timothy E
TE
Sanchez
L Chris
LC
Shih
Andre
A
D000758:Anesthesia / Q000662:veterinary*; D000818:Animals; D000831:Animals, Newborn; D002245:Carbon Dioxide / Q000378:metabolism*; D002302:Cardiac Output / Q000502:physiology*; D005260:Female; D006334:Heart Function Tests / Q000379:methods / Q000662:veterinary*; D006736:Horses / Q000502:physiology*; D007201:Indicator Dilution Techniques / Q000662:veterinary*; D008094:Lithium / Q000097:blood*; D008297:Male; D015203:Reproducibility of Results; D012119:Respiration
D002245:Carbon Dioxide; D008094:Lithium