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Clinical monitoring of cardiac output assessed by transoesophageal echocardiography in anaesthetised dogs: a comparison with the thermodilution technique
- Mantovani, Matheus M., Fantoni, Denise T., Gimenes, André M., de Castro, Jacqueline R., Flor, Patrícia B., Ida, Keila K., Schwartz, Denise S.
- BMC veterinary research 2017 v.13 no.1 pp. 325
- acepromazine, anesthesia, atropine, cardiac output, dogs, echocardiography, fentanyl, hypotension, isoflurane, monitoring, patients, risk, surgery, veterinary clinics
- BACKGROUND: Cardiac output (CO) is an important haemodynamic parameter to monitor in patients during surgery. However, the majority of the techniques for measuring CO have a limited application in veterinary practice due to their invasive approach and associated complexity and risks. Transoesophageal echocardiography (TEE) is a technique used to monitor cardiac function in human patients during surgical procedures and allows CO to be measured non-invasively. This prospective clinical study aimed to compare the transoesophageal echocardiography using a transgastric view of the left ventricular outflow tract (LVOT) and the thermodilution (TD) technique for the assessment of CO during mean arterial pressure of 65–80 mmHg (normotension) and <65 mmHg (hypotension) in dogs undergoing elective surgery. Eight dogs were pre-medicated with acepromazine (0.05 mg/kg, IM), tramadol (4 mg/kg, IM) and atropine (0.03 mg/kg, IM), followed by anaesthetic induction with propofol (3–5 mg/kg IV) and maintenance with isoflurane associated with a continuous infusion rate of fentanyl (bolus of 3 μg/kg followed by 0.3 μg/kg/min). The CO was measured by TEE (COTEE) and TD (COTD) at the end of expiration during normotension and hypotension (induced by isoflurane). RESULTS: There was a strong positive correlation between COTEE and COTD (r = 0.925; P < 0.0001). The bias between COTD and COTEE was 0.14 ± 0.29 L/min (limits of agreement, −0.44 to 0.72 L/min). The percentage error of CO measured by the two methods was 12.32%. In addition, a strong positive correlation was found between COTEE and COTD during normotension (r = 0.995; P < 0.0001) and hypotension (r = 0.78; P = 0.0223). CONCLUSIONS: The results of this study indicated that the transgastric view of the LVOT by TEE was a minimally invasive alternative to clinically monitoring CO in dogs during anaesthesia. However, during hypotension, the CO obtained by TEE was less reliable, although still acceptable.