Minimally Invasive Determination of Cardiac Output by Transthoracic Bioimpedance, Partial Carbon Dioxide Rebreathing, and Transesophageal Doppler Echocardiography in Beagle Dogs

Abstract

ABSTRACT. Minimally invasive cardiac output was determined using transthoracic bioimpedance (BICO), partial carbon dioxide rebreathing (NICO) and transesophageal Doppler echocardiography (TEECO) and compared to thermodilution (TDCO) in 6 beagle dogs. The dogs were 2 years old, weigh between 9.1-13.0 kg and were anesthetized with nitrous oxide-oxygen-sevoflurane. All dogs were administered a neuromuscular blocking drug and artificially ventilated during anesthesia. Thirty paired measurements of TDCO and each noninvasive method were collected during low, intermediate, and high values of cardiac output achieved by varying the depth of anesthesia and the administration of dobutamine. Cardiac output values ranged from 1.10-2.50 L/min for BICO compared to 0.81-4.88 L/min for TDCO; 0.70-2.60 L/min for NICO compared to 0.89-4.45 L/min for TDCO; and 0.59-4.37 L/min for TEECO compared to 0.57-4.15 L/min for TDCO. The limits of agreement and percentage error were -0.58 ± 1.56 L/min and ± 75.4% for BICO, -1.04 ± 1.08 L/min and ± 56.0% for NICO, and 0.03 ± 0.26 L/min and ± 12.3% for TEECO compared to TDCO. In conclusion, TEECO provided the best agreement to TDCO in sevoflurane anesthetized beagle dogs. KEY WORDS: beagle dog, cardiac output, minimally invasive measurement.

Cardiovascular Effects of Tramadol in Dogs Anesthetized with Sevoflurane

“…Cardiac output (CO) was determined by thermodilution method [31]. A volume of 3 ml of iced 5% dextrose (Terumo) was injected into the right atrium through the thermodilution catheter.…”

Cardiac index by thermodilution or transthoracic echocardiography in dogs at different hemodynamic states

“…This fact becomes even more important when the efficiency of transesophageal echocardiography is compared transthoracic echocardiography (YAMASHITA et al, 2007) due to the proximity and definition of the cardiac structures analyzed. In this study the evaluator was a cardiologist blinded to TD values to try to reduce the error.…”

Cardiac Output Monitoring

“…1 The NICO monitor may not provide an accurate determination of cardiac output in smaller dogs. 2 The size of the rebreathing circuit also limits the use of the device in dogs and cats.…”

“…In studies involving anesthetized dogs, results using this method are mixed compared with results using thermodilution. 2,7 The utility of this method is also somewhat limited in small animal practice because of equipment limitations, the time required to obtain acceptable studies, patient tolerance of the probe, and the need for highly trained personnel to be on hand to make the measurements. However, it does hold promise in limited applications (e.g., evaluation and monitoring of anesthetized patients).…”

“…The cardiac index is expressed in liters per minute per square meters (L/min/m 2 ). 2 The term combined cardiac output is used to describe the total volume of blood ejected into the systemic circulation over time when both the right and left ventricles can directly transfer blood to the arterial tree (e.g., fetal circulation, right-to-left patent ductus arteriosus).…”