How heart ultrasound changes anesthesia plans for cats

Abstract

OBJECTIVE: To assess the impact of preanaesthetic echocardiography on the subsequent intended anaesthetic management plan in cats with incidental clinical findings that may indicate cardiac disease. STUDY DESIGN: Clinical study involving cats undergoing echocardiography and subsequent anaesthesia. ANIMALS: A total of 40 client-owned cats. METHODS: Echocardiography was performed in conscious cats and the information was used to plan anaesthesia or sedation. An information sheet including relevant history, temperament, body condition score, clinical examination findings, current medication and results of any relevant tests such as haematology, biochemistry or Doppler blood pressure measurement was sent to three specialist anaesthetists and virtual case management plans were designed for each cat in two steps: step 1) anaesthetists were unaware of echocardiography results; and step 2) anaesthetists were aware of echocardiography results. In the second step the anaesthetists documented any changes to their original management plan, as either 'step-up' or 'step-down'. RESULTS: Of the 40 cats, 26 had murmurs, four had a gallop rhythm, four had both findings and six had other findings. Pathology of potential haemodynamic significance was found on echocardiography in 23 cats, 17 of which anaesthetists had correctly identified as having disease before echocardiography. A proportion of cats with murmurs were subsequently deemed to have no significant pathology after echocardiography. Echocardiography findings in these cases were: dynamic left ventricular outflow tract obstruction (DLVOTO) without hypertrophy; DLVOTO without hypertrophy + dynamic right ventricular outflow tract obstruction (DRVOTO); DRVOTO; valvular dysplasia; normal. In a median of 26/40 (range 16-38) of cases, the anaesthetic plan was changed after provision of further information; in 15/40 (8-20) cases, this was a 'step-up' in care and in eight/40 (6-23) it was a 'step-down' in care. In cases with atrial enlargement (left atrium to aortic ratio of >1.6) and deemed at risk of cardiac failure, alpha-2 agonist use changed considerably with availability of echocardiography findings. CONCLUSION: and clinical relevance Where there are abnormal cardiac findings on clinical examination in cats, echocardiography is required to accurately assess anaesthetic risk . The availability of echocardiographic information positively influences anaesthetic management.