BackgroundCardiac 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).ResultsThere 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).ConclusionsThe 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.
The aim of this paper was to compare the incidence of anesthetic complications in diabetic and nondiabetic dogs subjected to phacoemulsification. In total, 30 male and female dogs of different breeds were used. The dogs were distributed into two groups: diabetic (DG) (n=15) and control (CG) (n=15). The animals were premedicated with acepromazine (0.03mg/kg) and meperidine (4mg/kg), intramuscularly. After 20 minutes, anesthesia was induced with propofol (2 to 5mg/kg) and maintained with isoflurane. The animals were monitored and the heart rate, respiratory rate, peripheral oxyhemoglobin saturation, end tidal carbon dioxide tension, inspired and expired isoflurane fraction, and invasive arterial pressure were recorded at 10 minute intervals during the surgical procedure. Arterial hemogasometry was performed after anesthetic induction (T0) and at the end of the surgical procedure. Diabetic patients (DG 10±2 years) were older than non-diabetic group (CG 6±2 years). The expired isoflurane fraction after induction was 30% higher in the control group (CG 1.3±0.3%, DG 1.0±0.2%) (p<0.01). The most common anesthetic complication was hypotension. In total, 80% of the diabetic animals (n=12) exhibited mean arterial pressure (MAP) lower than 60mmHg (54±9.6mmHg) after anesthetic induction, and 83% of the hypotensive dogs (n=10) required vasoactive drugs to treat hypotension. Regarding hemodynamic changes, diabetic patients subjected to general anesthesia were more likely to exhibit hypotension which may be due to the response of older animals to the drugs used; however, this change deserves further investigation.
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