EQUINE | Proceedings
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 medical care . Critically , there has been no progress in the management of one of the most important complications , 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 idiots guide .
Ultrasonography
Like so much veterinary imaging , abdominal ultrasonography has become more practical as the necessary equipment has become more mobile and more affordable . 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 “ pregnancy ” 5MHz scanner , but machines capable of imaging the wing of the ilium and pelvis can produce quite reasonable images . Deep penetration of 20 – 25cm is necessary when trying to image the nephrosplenic space in large horses ( if you want to image the nephrosplenic space they are always large horses ). Otherwise penetration 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 simply because they had some tummy ache is also unlikely to increase your client base . Soaking the hair with alcohol will provide enough of a surfactant effect to enable reasonable ultrasonographic contact in most circumstances . 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 prevent any corrosion from the alcohol .
The key with ultrasound examination of colic is to appreciate 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 . However , with practice ultrasound examination is quick , inexpensive 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 examination 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 quickly . This is generally unrewarding due to the spleen occupying 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 echolucent , 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 colon . The gas and echogenic ingesta usually means that only the
26 • Equine Health Update •