Comparison of cardiac output measurements using transpulmonary thermodilution and conventional thermodilution techniques in anaesthetized dogs with fluid overload

Objective: To evaluate the agreement between cardiac output (CO) values obtained using a transpulmonary thermodilution technique (TPTDCO) and conventional thermodilution technique (TDCO) in anaesthetized dogs with fluid overload. Study design: Prospective experimental study. Animals: Six healthy Beagle dogs aged 7-8years. Methods: Dogs were anaesthetized with sevoflurane in oxygen, and catheters were inserted for TPTDCO and TDCO measurement. After instrumentation, baseline CO was measured using each technique at a central venous pressure (CVP) of 3-7mmHg. Dogs were subsequently administered lactated Ringer's solution and 6% hydroxyethyl starch to induce fluid overload. CO measurements were obtained using each technique at CVP values of 8-12mmHg, 13-17mmHg, 18-22mmHg and 23-27mmHg. Agreements between CO measurements obtained with the respective techniques were analysed using Dunnett's test, Pearson's correlation coefficient and Bland-Altman analysis. Results: Thirty pairs of CO values were obtained, ranging from 1.45Lminute(-1) to 4.69Lminute(-1) for TPTDCO and from 1.30Lminute(-1) to 4.61Lminute(-1) for TDCO. TPTDCO and TDCO values correlated strongly (r(2)=0.915, p<0.001). The bias and mean relative bias between TPTDCO and TDCO were 0.260.30Lminute(-1) (limits of agreement -0.29 to 0.81Lminute(-1)) and 9.7%, respectively. Conclusions and clinical relevance: TPTDCO and TDCO measurements obtained in anaesthetized dogs during fluid overload exhibited good agreement. Accordingly, transpulmonary thermodilution provides an accurate measurement of CO in dogs with fluid overload

Effects of gel pad thickness on skin stiffness evaluation by ultrasonographic strain elastography in normal dogs

Gel pads are commonly used for skin ultrasound examination; however, the effect of their thickness on the measured values is unknown. We investigated the effect of pad thickness on skin stiffness measurement in healthy dogs. The skin stiffness of the dorsal neck was measured using a durometer. Ultrasonographic strain elastography was performed with 5-, 10-, and 20-mm-thick pads. Among the strain ratios, muscle/skin (5 mm) showed a significantly positive correlation with skin stiffness. In the strain histogram, AREA (20 mm), CONTRAST (20 mm), MEAN (5, 20 mm), and STANDARD DEVIATION (20 mm) were significantly correlated with skin stiffness. In conclusion, the thickness of the gel pad affects the measurements during skin ultrasonographic strain elastography

Cardiovascular effects of total intravenous anesthesia using ketamine-medetomidine-propofol (KMP-TIVA) in horses undergoing surgery

Cardiovascular effects of total intravenous anesthesia using ketamine-medetomidine-propofol drug combination (KMP-TIVA) were determined in 5 Thoroughbred horses undergoing surgery. The horses were anesthetized with intravenous administration (IV) of ketamine (2.5 mg/kg) and midazolam (0.04 mg/kg) following premedication with medetomidne (5 µg/kg, IV) and artificially ventilated. Surgical anesthesia was maintained by controlling propofol infusion rate (initially 0.20 mg/kg/min following an IV loading dose of 0.5 mg/kg) and constant rate infusions of ketamine (1 mg/kg/hr) and medetomidine (1.25 µg/kg/hr). The horses were anesthetized for 175 ± 14 min (range from 160 to 197 min). Propofol infusion rates ranged from 0.13 to 0.17 mg/kg/min, and plasma concentration (Cpl) of propofol ranged from 11.4 to 13.3 µg/ml during surgery. Cardiovascular measurements during surgery remained within clinically acceptable ranges in the horses (heart rate: 33 to 37 beats/min, mean arterial blood pressure: 111 to 119 mmHg, cardiac index: 48 to 53 ml/kg/min, stroke volume: 650 to 800 ml/beat and systemic vascular resistance: 311 to 398 dynes/sec/cm5). The propofol Cpl declined rapidly after the cessation of propofol infusion and was significantly lower at 10 min (4.5 ± 1.5 µg/ml), extubation (4.0 ± 1.2 µg/ml) and standing (2.4 ± 0.9 µg/ml) compared with the Cpl at the end of propofol administration (11.4 ± 2.7 µg/ml). All the horses recovered uneventfully and stood at 74 ± 28 min after the cessation of anesthesia. KMP-TIVA provided satisfactory quality and control of anesthesia with minimum cardiovascular depression in horses undergoing surgery