title: Comparison of pulmonary artery and transpulmonary thermodilution cardiac output measurements in unsedated newborn calves.
abstract: OBJECTIVE
  To compare the agreement, repeatability and trending ability of transpulmonary thermodilution (TPTD) and pulmonary artery thermodilution (PATD) cardiac output (Q˙t) measurements in unsedated newborn calves.
  
  
  METHODS
  Prospective experimental trial.
  
  
  METHODS
  Eight newborn calves weighing a median (range) of 53 (46-59) kg.
  
  
  METHODS
  Pulmonary and femoral artery thermodilution catheters were placed under local anaesthesia. A total of 382 PATD and TPTD Q˙t measurements were performed simultaneously. Cardiac output was influenced by intravenous doxapram and theophylline in a randomized crossover fashion. Bland-Altman analysis for multiple comparisons, concordance and polar plots were used to assess TPTD against PATD.
  
  
  RESULTS
  Median (range) cardiac index values measured with PATD and TPTD were 197 mL kg(-1) minute(-1) (74-335 mL kg(-1) minute(-1)) and 196 mL kg(-1) minute(-1) (59-395 mL kg(-1) minute(-1)), respec-tively. A small mean bias of -3 mL kg(-1) minute(-1) with limits of agreement (LOA) of -64 to 58 mL kg(-1) minute(-1) and a percentage error of 31% were found. Eighty-two mean values were calculated. This reduced the LOA to -50 to 41 mL kg(-1) minute(-1) with a similar small bias and a percentage error of 23%. Mean TPTD tracked changes in Q˙t compared with mean PATD with 90% concordance, a mean polar angle of 6° and radial LOA of 43°, indicating marginal trending ability. Keeping the femoral artery catheter patent and obtaining acceptable measurements were very challenging because the calves were not used to being restrained. Calf movement had less influence on PATD.
  
  
  CONCLUSIONS
  We recommend that PATD remains the reference method to measure Q˙t in unsedated newborn calves. However, the robust results of the evaluation of the less invasive TPTD technique warrants further evaluation taking into account the difficulties reported in this study.
authors.affiliation: Section of Anaesthesiology, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Annette P N
authors.initials: AP
authors.lastname: Kutter
authors.affiliation: Section of Anaesthesiology, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Rahel S
authors.initials: RS
authors.lastname: Jud Schefer
authors.affiliation: Clinic of Reproductive Medicine, Department of Food Animals, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Bircher
authors.affiliation: Clinic of Reproductive Medicine, Department of Food Animals, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Uli
authors.initials: U
authors.lastname: Bleul
authors.affiliation: Section of Anaesthesiology, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Regula
authors.initials: R
authors.lastname: Bettschart-Wolfensberger
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D002302:Cardiac Output / Q000187:drug effects / Q000502:physiology*; D002417:Cattle / Q000502:physiology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D018592:Cross-Over Studies; D004315:Doxapram / Q000494:pharmacology; D005260:Female; D005263:Femoral Artery / Q000502:physiology; D008297:Male; D011651:Pulmonary Artery / Q000502:physiology*; D013806:Theophylline / Q000494:pharmacology; D013815:Thermodilution / Q000379:methods / Q000662:veterinary*; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D000697:Central Nervous System Stimulants; D014665:Vasodilator Agents; D004315:Doxapram; D013806:Theophylline
keywords: calves; cardiac output; monitoring; pulmonary artery thermodilution; transpulmonary thermodilution