Effect of Sevoflurane Anesthesia and Blood Donation on the Sonographic Appearance of the Spleen in 60 Healthy Cats

Abstract

The aims of this prospective study were to describe the normal sonographic size and appearance of the feline spleen, and to test effects of sevoflurane anesthesia and blood collection on sonographic characteristics. Sonographic evaluations were performed in 60 healthy blood donor cats prior to anesthesia and blood collection (baseline), after anesthesia induction, after completion of blood collection while under anesthesia, and 7-10 days after blood collection. Transverse sonographic images of the splenic mid-body were made. Splenic height, width, cross-sectional area, echogenicity relative to the left renal cortex, and echotexture were recorded. Height, width, and cross-sectional area were compared across time periods using linear-mixed effects models. Holm's method was applied to adjust for multiplicity and control the overall Type 1 error rate at α = 0.05. Normal transverse sonographic splenic measurements (mean ± standard deviation) at baseline were: height 8.2 ± 1.4 mm; width 26.7 ± 4.4 mm; and CSA 1.6 ± 0.5 cm(2) . While there were statistically significant differences in splenic height, width, and cross-sectional area after sevoflurane anesthesia and/or blood collection, differences were of low magnitude. The spleen was diffusely homogenous and subjectively isoechoic or mildly hyperechoic relative to the left renal cortex. In 77% of castrated male cats, the spleen was isoechoic to the left renal cortex. We conclude that sevoflurane anesthesia and blood donation do not subjectively alter splenic dimensions, echogenicity and echotexture in normal cats.

Administration of certain sedative drugs is associated with variation in sonographic and radiographic splenic size in healthy cats

“…Static ultrasound images of the spleen in the transverse plane were acquired at the level of the splenic head, body, and tail. Transducer angle was adjusted until the overall measurements were the smallest to avoid overestimation due to obliquity, as demonstrated in previous studies . Static images in the longitudinal plane were acquired at the level of the splenic body, with the major hilar vessels visible at the visceral surface.…”

“…Splenomegaly is a nonspecific finding in cats that can represent numerous regenerative, neoplastic, and inflammatory conditions . Reported causes of splenomegaly in cats include round cell neoplasia, extramedullary hematopoiesis, lymphoid hyperplasia, epithelial neoplasia, mesenchymal neoplasia, histiocytic sarcoma, myeloproliferative disease, pyogranulomatous inflammation, eosinophilic syndrome, and granulomatous splenitis .…”

“…Reported causes of splenomegaly in cats include round cell neoplasia, extramedullary hematopoiesis, lymphoid hyperplasia, epithelial neoplasia, mesenchymal neoplasia, histiocytic sarcoma, myeloproliferative disease, pyogranulomatous inflammation, eosinophilic syndrome, and granulomatous splenitis . Radiographic and sonographic evaluation of the spleen in cats often requires the administration of sedative drugs, which has anecdotally been associated with splenomegaly . Based on our review of the literature, only one abstract has been published that has evaluated the effects of sedation, in particular acepromazine, on splenic size .…”

“…In this abstract, the administration of intramuscular acepromazine to five young cats was associated with increased splenic size and a decrease in hematocrit . A recent study evaluated the effect of sevoflurane anesthesia and blood donation on the sonographic appearance of the spleen in healthy cats, showing significant differences in size after sevoflurane anesthesia and blood collection . A study performed in healthy cheetahs showed that splenic thickness was greater when the propofol‐fluothane combination was used compared to the medetomidine‐ketamine and alphaxalone‐alphadolone combinations for general anesthesia .…”

Ultrasonographic Appearance of Histoplasmosis Identified in the Spleen in 15 Cats

“…This mottled appearance was not apparent on images of less than 9 MHz and is also not uniquely different from that reported in normal cats. The normal spleen is typically homogeneous with a subtle mottled or heterogeneous appearance in higher resolution imaging . Much less common was the finding of discrete nodules, which was seen in only one of 15 cases.…”