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Bovine Field Anesthesia

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Presentation on theme: "Bovine Field Anesthesia"— Presentation transcript:

1 Bovine Field Anesthesia
Kathy Whitman, DVM, MS Great Plains Veterinary Educational Center

2 Refer to… Dr. Hostetler ppts and documents on thumb drive
Veterinary Clinics of North America, Food Animal Practice 2008, 24:2-3 Merck Veterinary Manual Food Animal Surgery, J.L. Noordsy, 1994 Large Animal Urogenital Surgery, Wolfe and Moll, 1999 Plumb’s Veterinary Drug Handbook, 2005 2006b.pdf sth_lecture.swf

3 Common anesthesia/analgesia for common procedures
Reproductive Teaser bull, testicular, prolapses Abdominal C-section, DAs, toggles, rumenotomy, explores, hernias Mammary gland Obstructions, lacerations Head Dehorning, enucleation Feet Amputation, tenotomy

4 Goals Focused (local/regional) anesthesia Tranquilization/Sedation
Standing procedures Combination with other anesthetics Tranquilization/Sedation Recumbent anesthesia Duration needs to be considered Gas induction +/- recumbency Shorter acting-gas takes over

5 Local anesthetic drugs
2% Lidocaine or 2% mepivacaine (20mg/ml) 0.1ml epinephrine (5l/ml):20ml local increased potency and duration Risk of tissue necrosis and spinal cord ischemia-don’t use for epidurals Toxic dose is roughly 4.5-5mg/lb (~250 ml for 1000 lb cow) Xylazine can be used in combination with locals for epidural anesthesia 20 mg ml lidocaine for caudal epidural in adult cow Combo with opioids is an option, but rarely used Ethyl alcohol-permanent “salvage” block Any concerns??

6 Local Anesthesia Procedures
Ring/line blocks Castrations, laparotomy, toggle, dehorning, mammary, etc. Epidural Perineal procedures (caudal); abdominal (lumbar) Paravertebral Pudendal Peterson; retrobulbar; auricular palpebral Cornual Regional limb perfusions-Bier block

7 Line/Ring blocks For all line/ring blocks…
18g needle, 1-1.5”-length is determined by depth of your incision Place a leading bleb Can buffer with 1:9 bicarb:lidocaine Do not infuse directly over incision site Distortion Hemorrhaging Possible healing delay Versatile, simple, safe

8 Line (Regional) block-Inverted L
Laparotomies Same concept bilaterally Infuse as much as needed ml Paralumbar fossa Line just below transverse processes Line just behind last rib As long as your incision Deep enough to get through muscles-infuse as you pull out Block Incision Nerve pathways

9 Caudal epidural Perineal anesthesia Desensitizes tail
+/- reduced straining 1ml 2% lidocaine/200 lb to keep standing 18 g 1.5” needle Clip and clean area if possible “Pump” tail with one hand while palpating midline of coccygeal vertebra Large gap=needle placement On midline, vertical to space “Hanging drop” technique Administer if little resistance is met

10 Proximal Paravertebral
Surgical prep 1.5-2” lateral to midline 4-5” spinal needle, +/- stab incision Walk off transverse process cranially 10-15 ml lidocaine infused per site Expect scoliosis

11 Distal Paravertebral Surgical prep 1.5-2” lateral to midline
” hypodermic needle Direct needle dorsally over transverse process and liberally infuse, “fan” over process, then repeat ventrally without pulling out needle 20-30 ml lidocaine infused per transverse process Expect scoliosis

12 Internal pudendal Procedures similarly blocked by epidurals
Penile relaxation Clipped, scrubbed, superficial block 14g guide needle inserted in ischiorectal fossa 18g 4-5” spinal needle inserted and directed rectally to the nerve identified lying on the sacrosciatic ligament ml lidocaine

13 Head anesthesia-Cornual
Crest of frontal bone Cornual nerve 5-10 ml lidocaine SQ

14 Head anesthesia-Auriculopalpebral
Crest of frontal bone Auriculopalpebral nerve 5-10 ml lidocaine SQ

15 Head anesthesia-Retrobulbar
Surgical scrub (if enucleating) Mild sedation and proper head restraint Begin with ring block +/- auriculopalperbral block to desensitize eyelid +/- topical corneal anesthesia (proparicaine) 5” needle-14g catheter needle works well 2pt or 4pt placement 15 ml lidocaine per placement Use finger to deflect orbit, follow along the bone of the socket Upper eyelid Optic nerve Globe

16 Head anesthesia-Peterson block
More challenging? Safer? Direct an 18g 4-5” needle into the cranioventral aspect of the notch through 14g “cannula” Advance to the coronoid process Walk off the cranial aspect of the coronoid process Advance until bony contact, or conus of the eye is penetrated (“pops”) 20 ml lidocaine Coronoid process Zygomatic arch Supraorbital process

17 Foot anesthesia Can do similar to equine nerve blocks-just appreciate anatomical variations Ring block or specific nerve blocks may be useful when venous access is impaired Local infusion is more common-access to any venous structure should suffice 20 ml lidocaine via 20g needle or butterfly catheter Tourniquet provides hemostasis and can be left on for up to 1 hour Opportunity for permanent blocks?

18 Mammary anesthesia Ring blocks are most common Clip and scrub
Sedation advisable Short, fine needles for lidocaine infusion Enough lidocaine to make a bleb Infusion into streak canal if mucosal desensitization is required Gland cistern Teat cistern Streak canal and sphincter

19 Indications for chemical restraint
Standing sedation/tranquilization Recumbency Intractable cattle Standing procedures Euthanasia Facilities may dictate Safety Invasive surgery Ventral c-section, penile translocation, terminal procedure Duration of surgery Flexibility to use gas Safety of patient and surgeons Uncooperative patient Poor handling facilities

20 Routes of administration for chemical restraint
IV Jugular Tail Auricular Milk vein-caution Cephalic IM/SQ BQA-neck administration Delayed onset/Longer duration of action Safety

21 Sedative drug options and doses (mg/100lb)
Xylazine 100mg/ml: IV; IM ( ml/100lb IV; ml/100lb IM) 1/10 equine dose, for reference Acepromazine 10mg/ml: IV, IM, orally ( ml/100lb) Combinations Xylazine+ace: reduce both doses, can combine in same syringe Xylazine+Butorphanol: add up to 2.25mg/100lb (~0.2 ml/100lb) Standing Ket-stun IV Butorphanol 10mg/ml ( ml/100lb) Xylazine ( ml/100lb) Ketamine 100mg/ml ( ml/100lb) Standing Ket-stun IM/SQ ( technique) – for 1000lb cow (SQ preferred to minimize recumbency) 5 mg Butorphanol (0.5ml) 10 mg Xylazine (0.1ml) 20 mg Ketamine (0.2ml)

22 Injectable drugs and doses (mg/100lb) to achieve recumbency
Xylazine: ( ml/100lb; 3ml for 1000lb cow is generally sufficient) Xylazine+Ketamine IV administration: 2.25 mg (0.2ml/100lb) xylazine first, 180 mg (1.8ml/100lb) ketamine after marked sedation or recumbency is achieved IM administration: mg ( ml/100lb) xylazine mg (1.8ml/100lb) ketamine (can be combined in same syringe) Ket-stun IM/SQ 1.15 mg (0.15ml/100lb) 2.25 mg (0.02ml/100lb) 4.5 mg (0.045ml/100lb) Recumbent Ket-stun IV mg ( ml/100lb) Butorphanol mg ( ml/100lb) Xylazine mg ( ml/100lb) Ketamine BXK Stock solution Mix 100mg xylazine (1ml) + 10mg Butorphanol (1ml) into bottle of unconstituted ketamine (1000mg) 1ml/45lb IM

23 Reversal drugs Alpha 2 antagonists
Yohimbine-traditional, not for use in food animals, effectiveness? Tolazoline 100mg/ml-labeled for horses, ELDU in cattle 80mg-200mg/100lbs ( ml/100lbs) Slow IV administration Lower end for reversal, higher end for emergency

24 Analgesics No longer an option
Make it a part of your protocol and work in the cost Anesthetic drugs may/may not be sufficient Xylazine and ketamine have some/acepromazine NONE Consider premed with antibiotics and anesthetics Reduce wind-up, reduce anesthetic dose, lengthen anesthesia

25 Analgesic drug options/dosages (mg/100lb)
Flunixin 50mg/ml: mg IV ( ml/100lb) Meloxicam 15mg tabs: 45mg PO (3 tabs/100lb) Butorphanol: 2.25 IV(0.2ml/100lb, have not used over 2ml) Good when combined with other sedatives/anesthetics Appetite stimulant Margin of safety Local anesthetic: Lidocaine can provide short duration analgesia Carbocaine for longer duration, still short lived

26 Areas of concern…. Legality of drugs Drug safety
ELDU AMDUCA/FARAD Drug safety Bloat and regurgitation if recumbent Lethal dose of lidocaine Alpha 2 sensitivity Analgesic toxicity Emergency preparedness Orogastric tube on hand Endotracheal tube on hand Alpha-2 antagonist drawn up From 1997; From 2003 Tolazoline , IV


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