Effect of Sedation on Contrast‐enhanced Ultrasonography of the Spleen in Healthy Dogs

Abstract

Contrast-enhanced ultrasound of the spleen enables the dynamic assessment of the perfusion of this organ, however, both subjective and quantitative evaluation can be strongly influenced by sedative agent administration. The purpose of this prospective, experimental study was to test effects of two sedative agents on splenic perfusion during contrast-enhanced ultrasound of the spleen in a sample of healthy dogs. Contrast-enhanced ultrasound of the spleen was repeated in six healthy Beagles following a cross-over study design comparing three protocols: awake, butorphanol 0.2 mg/Kg intramuscular (IM), and dexmedetomidine 500 μg/m(2) IM. After intravenous injection of a phospholipid stabilized sulfur hexafluoride microbubble solution (SonoVue®, Bracco Imaging, Milano, Italy), the enhancement intensity and perfusion pattern of the splenic parenchyma were assessed and perfusion parameters were calculated. Normal spleen was slightly heterogeneous in the early phase, but the parenchyma was homogeneous at a later phase. Sedation with butorphanol did not modify perfusion of the spleen. Dexmedetomidine significantly reduced splenic enhancement, providing diffuse parenchymal hypoechogenicity during the entire examination. Measured parameters were significantly modified, with increased arrival time (AT; (< 0.0001) and time to peak (TTP; P < 0.0001), and decreased peak intensity (PI; P = 0.0108), wash-in (P = 0.0014), and area under the curve (AUC; P = 0.0421). Findings supported the use of butorphanol and contraindicated the use of dexmedetomidine as sedatives for splenic contrast ultrasound procedures in dogs. Short-term and diffuse heterogeneity of the spleen in the early venous phase was determined to be a normal finding.

Contrast‐enhanced ultrasonography characteristics of intrathoracic mass lesions in 36 dogs and 24 cats

“…Cats had a significantly earlier absolute TTE (mean 5.7 s) than dogs (mean 10.5 s). The values in dogs were slightly higher than previously reported in sedated canine patients . Rossi et al.…”

“…Rossi et al. published an arrival time of contrast in the spleen of 8.77 ± 1.16 s in non‐sedated dogs and 7.6 ± 1.16 s in butorphanol‐sedated dogs . Reasons for the difference are unclear due to the different study designs and amount of sedation.…”

“…Most of the patients were sedated with a small dose of butorphanol. The influence of anesthesia on CEUS has been studied and reports have shown that certain anesthetics have a significant influence on contrast enhancement in dogs and cats . TTE was reportedly delayed in anesthetized cats and dogs, and anesthesia may increase heterogeneity in the spleen of cats .…”

“…The influence of anesthesia on CEUS has been studied and reports have shown that certain anesthetics have a significant influence on contrast enhancement in dogs and cats . TTE was reportedly delayed in anesthetized cats and dogs, and anesthesia may increase heterogeneity in the spleen of cats . Butorphanol sedation and propofol anaesthesia have been found to not influence blood volume or CEUS parameters …”

Effect of sedation with butorphanol on variables pertaining to the ophthalmic examination in dogs

“…The authors used this knowledge and their combined experience to choose an in‐between dose of 0.2 mg/kg of butorphanol for the current study. The studied dose was injected intramuscularly because this mode of administration is easier to use in uncooperative patients than the intravenous injection, and because intramuscular injection of 0.2 mg/kg butorphanol has been previously reported to be suitable for abdominal ultrasonography in dogs which also requires adequate sedation . Although none of the dogs included in the study showed signs of aggression, all were excitable dogs in the company of human beings and their excitement was visibly reduced in 21 of them after treatment.…”