Equine Health Update EHU Vol 19 Issue 3 - Page 26

EQUINE | Proceedings Medicine And Ultrasonography: All The Omnicompetent Surgeon Needs To Know By Bruce Bladon Debatably, the great advances in recent years in colic surgery have been in diagnosis and in intensive medi- cal care. Critically, there has been no progress in the management of one of the most important complica- tions, post operative ileus. This lecture will try to provide a practical guide to what actually works in critical care, what the internal medicine specialists might term an idi- ots guide. Ultrasonography Like so much veterinary imaging, abdominal ultraso- nography has become more practical as the necessary equipment has become more mobile and more afford- able. We still regularly use the Micromaxx scanners (BCF) with a 2 – 3.5MHz probe. It is not possible to get reasonable abdominal images with a standard “preg- nancy” 5MHz scanner, but machines capable of imaging the wing of the ilium and pelvis can produce quite rea- sonable images. Deep penetration of 20 – 25cm is nec- essary when trying to image the nephrosplenic space in large horses (if you want to image the nephrosplenic space they are always large horses). Otherwise penetra- tion of 15cm is usually adequate. Skin contact is ideally achieved by clipping and applying coupling gel. This is simply not practical in colic cases – clipping all the hair off the abdomen of a hairy pony who has been rolling around in mud for half the night is a big job, likely to take half an hour, and sending home a smart dressage horses looking like a chessboard sim- ply because they had some tummy ache is also unlikely to increase your client base. Soaking the hair with alco- hol will provide enough of a surfactant effect to enable reasonable ultrasonographic contact in most circum- 26 stances. Surgical spirit is harmful to ultrasound probes and causes lens delamination. Iso-propyl alcohol is less corrosive to the probe and is more or less “safe”. Plastic sleeves are now widely available for probes and will pre- vent any corrosion from the alcohol. The key with ultrasound examination of colic is to ap- preciate that it is a low yield procedure, similar to other investigations of the colic case. Ultrasound examination will not provide a detailed diagnosis in all cases. How- ever, with practice ultrasound examination is quick, in- expensive and provides more information than a rectal examination, and for a different part of the abdomen. It is our practice, when we admit a colic, to place the horse in stocks, to take a blood sample, to do a rectal examina- tion after treatment with Buscopan® and / or sedative, and to perform abdominal ultrasonography. We have a single fee to include all these investigations, “Assess Colic at Donnington Grove Veterinary Surgery”. The technique of abdominal ultrasonography is to soak the left flank in isopropyl alcohol and examine this quick- ly. This is generally unrewarding due to the spleen oc- cupying the entire flank. Through the 17th inter-costal space, using a dorso-ventral orientation, the kidney can usually be visualised deep to the spleen. Obliteration of this view by gas filled gut may indicate nephrosplenic entrapment. However this finding is not definitive and many false positives occur. Equally false negatives are possible if the gut is non distended and hence echolu- cent, though this is less usual in our experience. The stomach can be imaged in many cases, on the left side, ventrally and cranially. The stomach typically has a two layer wall, formed by the omentum. It is normal to see the stomach back to T 12 or 13, but further caudal than this suggests distension. Ventrally one of the commonest findings is ۋB\[X[\H\X[HYX[]ۛHB(\]Z[HX[\]H8(