bovine surgical procedures key terms: casting, cosmetic dehorning, hemostasis, horn button, myiasis,...
TRANSCRIPT
Bovine Surgical ProceduresKey Terms: Casting, Cosmetic
Dehorning, Hemostasis, Horn Button, Myiasis, Scur, Supernumerary teats,
tipping
Chapter 12
Objectives
• differences between standing surgical procedures vs. general anesthesia procedures.
• Prepare a patient for surgery. • Assist and/or perform induction and maintenance of
anesthesia. • Provide anesthetic monitoring. • Manage the patient during recovery and immediate
postoperative periods. • Understand the basic risks and possible complications
associated with anesthesia and surgery, and implement preventive measures when indicated.
Bovine Surgery
Chapter 12: Bovine Surgery
• Valuable animals– High producing dairy
female– Registered breeding
stock– Pet animals
Jan 2010: A two-year-old Aberdeen-Angus bull has been sold to an American buyer for what is believed to be a UK record price of 75,000gns
Bovine Surgery
• Standing– Lacerations/ punctures– Castration, c-section– LDA/ RDA– Enucelation, dehorning– Distal limb injuries
• General anesthesia• Heavy sedation and
casting– Limbs and feet
After opening the sterile pack of surgical supplies and draping the cow, the patient is ready for a standing cesarean section via the left flank
Utrecht (1975)
LDA
• Rumen– inspection, palpation– auscult – frequency &
character• Ping (fluid-gas)
– Abomasum: LDA– Rumen: normal unless
otherwise (palpate for rumen)
– 1-3/minute• 1º rumen/reticulum• 2º rumen only
Preparation for Bovine Surgery
• Facility: clean, dry and draft free• Sedation/ tranquilizers– Depress GI motility > bloat/ ruminal tympany– Regurgitation
• Withdraw food: 12 – 24 hours• Withdrawal water: 6 hours
• Local anesthesia/ blocks: in addition to sedatives– L Block, paravertebral block, cornual nerve block, IV
regional analgesia, caudal epidural analgesia
Preparation for Bovine Surgery
• Local Block Drugs– Lidocaine (cheapest and safest)• lidocaine toxicity: muscular tremors, severe
depression, hypotension , occasionally convulsions• Toxic dosage: > 13cc of 2% lidocaine per 100 lb or > = 13 mg/kg
– mepivacaine, bupivacaine– Withdrawal time
L Block
• Used for standing flank laparotomies• Most common• Procedure– Complete surgical prep.– Place anesthetic in an inverted L configuration using a
18 × 1 1/2- to 3-in needle.– Anesthetic is placed: SQ, muscular layers– Amounts of anesthetic: 60 – 100 ml of 2% lidocaine
for adult cattle– Allow 10 to 15 minutes to take effect.
Paravertebral Block
• Use– To create a large flank anesthetic zone• Skin to peritoneum
– Blocks T13, L1, and L2
• Prep – Surgical prep
• Procedure – Two approaches: Dorsal and lateral
Paravertebral Block (cont’d)
• Dorsal approach/ Farquason or Cambridge method/ proximal paravertebral method– Near the intervertebral foramina– A 16- or 18-gauge needle, 3 to 6 inches in length
• A 18- or 20-gauge for smaller ruminants – Or placement of a 14-gauge × 1-in needle first and then insert an 18-
gauge needle through the 14-gauge needle
– Place 20 ml per injection site • Use 2 to 5 ml for sheep and goats
– Block: skin to the peritoneum, including the longissimus muscle– Can create a temporary curvature of the spine (scoliosis, because of
blocking lingissimus m.) , making it difficult to close the incision
Paravertebral Block (cont’d)
• Lateral approach/ distal paravertebral method/ Magda or Cornell method– Near the tips of the transverse processes of the
lumbar vertebrae– A 18-gague × 1 1/2- to 3-in needle • 20-22 gauge × 1 for sheep and goats
– Use 10 to 20 ml per injection site • Use 2 to 4 ml for sheep and goats
Paravertebral Block (cont’d)
Cornual Nerve Block
• Use – Desensitization of the horn and horn base
• Preparation– Surgical preparation
• Procedure
– Cattle – Goats
Cornual nerve: blocked halfway between the lateral horn base and the lateral canthus of the eye, horn is continuous with frontal sinus
Cornual Nerve Block (cont’d)
• Single nerve• Amount and depth– Calves: 3 to 5 ml, 1 cm– Adults: 5 to 10 ml, 2.5 cm (large adults)
• A 18- to 20-gauge × 1 to 1 1/2-in needle• Well developed horns in adults: 2nd injection
on base of horn and caudal aspect under the skin
Intravenous Regional Analgesia (Bier Block) • IV analgesia is considered superior to local nerve blocks/ ring
blocks for most surgical procedures of the distal extremities.
• Preparation – Surgical preparation
• Procedure – Restrain, sedate, and cast.– Apply tourniquet: Padding should be in place underneath.
• Cotton/ foam padding• For feet procedures, place at midcarpus or midtarsus.• For proximal procedures, place just proximal to carpus or tarsus.
Intravenous Regional Analgesia• Procedure– Inject IV into any large superficial vein.– Dorsal metatarsal/ metacarpal vein– Plantar/ palmar MT/MC vein
– Cattle: 18- to 20 G– Small ruminants: 22- to 25 G– Use 10 to 30 ml: 2% lidocaine/ mepivacaine– Wait for 10 to 15 minutes.– Do not leave tourniquet in place for longer than 2 hours.– Slowly release tourniquet: anesthetic wear off 5 to 10 min.
Caudal Epidural Analgesia• Common in obstetrics and prolapses: uterus, vaginal, rectum• Blocks: anus, perineum, vulva, caudal vagina,caudal aspects -
thighs• Preparation
– Surgical preparation• Procedure
– Placement on the dorsal aspect of the tail base at the first intercoccygeal space; the sacrococcygeal space is less common
– Palpate tail up and down for proper placement.– A 18 × 1 1/2-in needle at a 45-degree angle.– Use 1 ml/100kg: 2% lidocaine, mepivacaine, xylazine– Allow 10 to 20 minutes for effect; lasts 1 to 2 hours.
CAUTION: can cause HL ataxia with too much anesthetic
Cranial epidural: L-S space are not common: difficult to perform, posterior paralysis “splay legs”
• For prolonged anesthesia: small diameter epidural catheter• DA: kinking catheter/ plugged with tissue/ fibrin
General Anesthesia• Anesthetic risks: uneventful
recoveries– Prone to regurgitation
• Aesthetic drugs relax smooth muscle
• Aspiration pneumonia• Withdraw food and
water• Cuffed ET tube• Quick intubation• Don’t roll ruminants
Preputial surgery: http://www.drostproject.org/en_bovrep/12-56/itemtop15.html
General Anesthesia (cont’d)
General Anesthesia• Anesthetic risks
– Prone to distention of the rumen (bloat)• Fast• Have equipment ready in case
you have to treat
– Prone to hypoventilation• Fast• Appropriate anesthetic depth
– Compartment syndrome• Myopathy, neuropathy• Padded stall
• Uneventful recoveries
General Anesthesia (cont’d)
• Preanesthetic preparation– Preanesthetic evaluation: PE– Preanesthetic drugs • Acepromazine : Phenothiazine derivative. Calms animal–Prolonged penile relaxation–2 -4 hrs. tranquilization (not great tranquilizer)–Don’t use in dehydrated patients: hypotension
General Anesthesia (cont’d)
• Preanesthetic preparation – Xylazine: use 20 mg/ml; alpha2 agonist• Dosage: 0.05 – 0.1 mg/kg IV; 0.1 – 0.5 mg/kg IM• Very sensitize: 1/10 dose; Hereford/ Brahman • Effects: bloat, bradycardia, resp. depression,
hyperglycemia (osmotic diuresis); uterine contractions (premature labor); transmammary transmission• Reversal: Yohimbine, Tolazoline
General Anesthesia (cont’d)
• Preanesthetic preparation– Detomidine/ Medetomidine: alpha 2 agonists• Reversal: atipemazole
– Anticholinergics: atropine, glycopyrrolate• Antisialogues• Reduce incidence of bloat
General Anesthesia (cont’d)
• Induction Drugs: – Inhalant gases (< 150 lb. face mask: halothane: 3-4%;
isoflurane: 4-6%; sevoflurane: 4-6%)– Thiobarbiturates: not is < 3 months, crosses placenta– Ketamine: combo with xylazine or acepromazine– Guaifenesin: combo as muscle relaxant; not > 5%:
hemolysis; triple drip: xylazine/guaf/ketamine bit has cardio and resp .challenges
– Telazol: tiletamine – zolazepam; calves and small ruminants
– Propofol: anesthesia for 10 minutes
General Anesthesia (cont’d)
After induction than pass et TUBE•Direct visualization: laryngoscope, sternal recumbency: stylet•Palpation of epiglottis
KNOW table 12 -1 and 12 -2
DON’T USE Nitrous oxide
General Anesthesia (cont’d)• Maintenance of anesthesia
– Short: injectable drugs/ inhalants and long procedures > 60 mins. : general anesthesia• Depth
– Ocular reflex: corneal reflex has to be present and palpebral reflex is delayed
– Eyeball position» Light: ventromedial» Deep: central
– Pupil size: mydriasis: overdose of inhalant
– Muscle movement: none when scalpel is used
• Monitoring of anesthesia– Ventilation
» RR and tidal volume (depth): 20-40 / min.
» Mm color» Blood gas monitor
– Circulation» Pulse strength: coccygeal,
median, auricular, femoral» Mm» CRT» HR: 60-120 bpm
– BP: MAP > 70 mm Hg if less than 60 hypotension
– Monitor temp.
General Anesthesia (cont’d)
• Fluids– IV fluids : LRS: 5-10
ml/kg/hr.; neonates may need dextrose
– Oxygen supplementation• Recovery: usually eventful– Start with 100% oxygen– Sternal recumbency– Remove tube after
swallowing reflex with partial cuffed ET tube
References
• K Holtgrew-Bohling , Large Animal Clinical Procedures for Veterinary Technicians, 2nd Edition, Mosby, 2012, ISBN: 97803223077323
• http://www.drostproject.org/• http://www.cvmbs.colostate.edu/clinsci/
callan/bovine.htm• http://www.farad.org/index.asp• http://informedfarmers.com/control-and-
prevention/