title: Use of lithium dilution and pulse contour analysis cardiac output determination in anaesthetized horses: a clinical evaluation.
abstract: OBJECTIVE
  To assess the suitability of a human algorithm for calculation of continuous cardiac output from the arterial pulse waveform, in anaesthetized horses.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  Twenty-four clinical cases undergoing anaesthesia for various conditions.
  
  
  METHODS
  Cardiac output (Qt), measured by lithium dilution (QtLiDCO), was compared with a preceding, calibrated Qt measured from the pulse waveform (QtPulse). These comparisons were repeated every 20-30 minutes. Positive inotropes or vasopressors were administered when clinically indicated. Cardiac indices from 30.7 to 114.9 mL kg(-1) minute(-1) were recorded. Unusually shaped QtLiDCO curves were rejected and the measurement was repeated immediately.
  
  
  RESULTS
  Eighty-nine comparisons were made between QtLiDCO and QtPulse. The bias between the mean (+/-SD) of the two methods (QtLiDCO - QtPulse) was -0.07 L minute(-1)(+/-3.08) (0.24 +/- 6.48 mL kg(-1) minute(-1)). The limits of agreement were -12.72 and 13.2 mL kg(-1) minute(-1) (Bland & Altman 1986; Mantha et al. 2000). Linear regression analysis demonstrated a correlation coefficient (r2) of 0.89. Cardiac output in individual patients varied from 49.1 to 183% of the initial measurement at the time of calibration. Linear regression of log-transformed Qt variation for each method found a mean difference of 9% with limits of agreement of -4.1 to 22.1%.
  
  
  CONCLUSIONS
  This method of pulse contour analysis is a relatively noninvasive and reliable way of monitoring continuous Qt in the horse under anaesthesia. The ability to easily monitor Qt might decrease morbidity and mortality in the anaesthetized horse.
authors: Equine Referral Hospital, Royal Veterinary College, Hertfordshire, UK.
authors: Gayle D
authors: GD
authors: Hallowell
authors: Kevin T T
authors: KT
authors: Corley
mesh_terms: D000768:Anesthesia, General / Q000662:veterinary*; D000818:Animals; D002302:Cardiac Output / Q000502:physiology*; D006736:Horses / Q000502:physiology / Q000601:surgery*; D007201:Indicator Dilution Techniques / Q000662:veterinary; D018021:Lithium Chloride; D016343:Monitoring, Intraoperative / Q000379:methods / Q000662:veterinary*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011674:Pulse
chemical_list: D018021:Lithium Chloride