Cardiovascular and respiratory alterations in dogs during cervical myelography using ioversol

Abstract

Subarachnoid infusion of most contrast mediums and the steps involved in performing a cervical myelography have adverse affects that can discourage its use in the radiographic diagnosis of spinal cord diseases. Thus, the cardiovascular and respiratory alterations associated with neck flexion, subarachnoid puncture, and cerebrospinal fluid drainage during subarachnoid infusion of ioversol (320mgI/mL) in dogs under general anesthesia using isoflurane were evaluated. The dogs received subarachnoid infusion of autologous cerebrospinal fluid kept at 38°C -control group (GC); ioversol 0.3mL/kg at 25°C (GI25) and ioversol 0.3mL/kg heated to 38°C (GI38). Each dog had its heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), respiratory rate (RR), oxyhemoglobin saturation (SaO 2 ) and electrocardiography readings (PR and QT intervals) recorded. Group comparisons showed no statistical difference regarding neck positioning, subarachnoid puncture, and subarachnoid infusion of contrast medium on HR, RR and SaO 2 , cardiac rhythm or conduction. However, isoflurane significantly increased PR and QT intervals. Based on these findings, it is concluded that the steps involved in cervical myelography and the use of ioversol 320mgI/mL at 0.3mL/kg (25ºC and 38ºC) during cervical myelography did not result in relevant cardiovascular and respiratory alterations, except for an elevation in arterial pressure after injection of ioversol.Keywords: dog, myelography, optiray 320, cardiac arrhythmia, arterial pressure mielografia, optiray 320, arritmia cardíaca, pressão arterial RESUMO Os efeitos adversos provocados pela infusão subaracnoidea de meios de contraste e da mielografia cervical podem desencorajar sua aplicação como alternativa para o diagnóstico radiológico de doenças da medula espinhal. Assim, avaliaram-se os efeitos cardiovascular e respiratório dos procedimentos técnicos necessários à mielografia cervical e da infusão subaracnoidea do ioversol -320mgI/mL -em cães anestesiados com isofluorano. Foi realizada infusão do líquido cefalorraquidiano autólogo mantido a 38°C -grupo-controle (GC); infusão do ioversol 0,3mL/kg a 25°C (GI25); e infusão do ioversol 0,3mL/kg aquecido a 38°C (GI38). Estudaram-se: pressões arteriais sistólica (PAS) e diastólica (PAD), frequências cardíaca (FC) e respiratória (FR), saturação de oxi-hemoglobina (SaO 2 ) e medidas eletrocardiográficas (intervalos PR e QT