OSCE 2026

DRUGS (co and bp caclulations)

CO = hr x sv

BP = CO x svr

drugs that lower hr will lower bp as a side effect

drugs that lower bp will increase hr to compensate

Acepromazine

• Premed, a1 phenothiazine tranquiliser, no analgesia, non-reversible

• lasts 6-8hrs

• Sedative, vasodilation and hypotension

• NOT in boxers, stallions

Àlfaxan

• Neurosteriod, gaba agonist, no analgesia

• Induction, respiratory depression/apnoea

Atipamezole

• a2 antagonist, medetomidine reversal

Atropine

• anticholinergic, increases hr primarily and increases bp also as a side effect

• ONLY IN EMERGENCIES

Butorphanol

• partial mu antagonist, kappa agonist, sedation, mild pain relief (blocks receptor so can’t give good pain relief but kappa gives some pain relief)

• use for scale and polish, imaging, scopes, bandage changes, ear flush - ANYTHING NON-PAINFUL

Diazepam

• benzodiazepine, induction combo, flumazenil reversal

• muscle relaxant during seizures

Dopamine

• catecholamine, increases map - IF SEVERE HYPOTENSION

Fentanyl

• Pure mu agonist, CRI, naloxone reversal

• IV duration is 20 mins, fentanyl patch onset in 12hrs, lasts 3 days.

Glycopyrrolate

• Anticholinergic, increase hr, lasts longer but takes longer to work

• older patients and longer procedures

Lignocaine

• local, anti-arrhythmic for vps (ventricular premature contractions) - leading to vtac

Medetomidine

• atipamezole is the reversal

• alpha-2 adrenergic agonist, sedative and analgesic

Phase 1: vasoconstriction —> hypertension —> reflex bradycardia

Phase 2: Vasodilation —> hypotension —> still bradycardia

Meloxicam

• NSAID, after procedure to control pain relief, not in kidney issues or dehydration

Methadone

• pure mu, bradycardia

Naloxone

• Opioid reversal

Propofol

• Induction, respiratory depression and cardiac depression

Rebreathing Anaesthetic Machine Check

1. Attach hoses (02, and scavenge)

2. Turn scavenge on and 02 flush

3. Turn 02 on full then drop of 2L/in and do seal check

4. Vaporiser on 0 and do seal check

5. o2 and vaporiser off

6. Check iso and turn dial all the way

7. Check soda lime

8. Attach fresh gas hose to common gas outlet

9. Attach rebreathing circuit and bag

10. Check circuit for leaks - inflate to 20cm/H20

11. Empty bag until wrinkles - squeeze and observe one-way valves

12. Open spill valve and squeeze bag

Non-rebreathing Anaesthetic Machine Check

1. Attach hoses (02 and scavenge)

2. Turn scavenge on and 02 flush

3. Flowmeter on full then back to 2L/min and seal check

4. Vaporiser on 0 and seal check

5. 02 and vaporiser off

6. check iso and rotate vaporiser dial all the way

7. attach non-rebreathing circuit including bag (to common gas outlet and scavenge hose to spill valve)

8. perform a leak test filling bag to 20cm H20

9. open spill valve and squeeze bag

Catheter Placement Explain

Radiography - Lateral Thorax

Radiography - VD Thorax

Radiography - Lateral Abdomen

Radiography - VD Abdomen

PALACE

• Positioning

• anatomy

• label

• artefacts

• collimation

• exposure

X-ray principles

• 3 interactions with matter (penetration - black, absorption - white, scatter - degrades image quality - AVOID USING GRID)

• 3 exposure factors:

kvp: QUALITY - kilovoltage peak/pentration power - contrast

mA: QUANTITY (want large)

time: mAs (want shortest time) - density

Grids: increase quality and decrease scattered radiation - between patient and image receptor - when body area >10cm (in a bucky - remove grid lines)

Radiography PPE requirements

• we are allowed 20mcv/yr, normally only 1msv/yr

• ALARA: as low as reasonably achievable

• we must have a licence

• 4 pillars of radiation safety - distance, time, shielding, common sense

lead gowns, thyroid collars, lead gloves, hand/arm shields, lead glasses

reduce exposure: out of room, PPE, restraint, distance, collimate (lower beam size), exposure approp

Surgical Prep

clipping margins and positioning

prep stages and techniques

necessary instruments/equipment

Spey Margin: cranial diaphragm, mid pelvis caudally, 10-20cm laterally depending on dog size --> Rochester Carmalts to crush pedicles

Castrate: cranial prepuce, above/below scrotum (don’t clip), 10cm laterally 

40 clipper blade, 10 for tick clip (not close to skin)

 

Prep: aqueous chlorhex 1:1 5 mins general scrub, concentric circles methylated spirits spin until no longer pink or stars on uneven surgical field (to remove oils from skin), chlorhex and alcohol spray in theatre

Gowning and gloving Explain

ET tube cuff inflation

only inflate cuff while giving breaths

give breaths below 20cm H20

intubate with left hand and hold laryngoscope with right hand

Injection Sites (SQ and IM)

on neck, tent skin and insert needle and draw back

IM: epaxial muscles (cranial margin: last rib, caudal margin: ilium wings, medial margin: spinal ridge, distal lateral: transverse process of lumbar vertebrae - 90 degree angle and rest wrist!!!!

Fluid Rate Calculations

5ml/kg/hr surgical

2-3ml/kg/hr maintenance

Admission Procedures for Surgical Patients

Patient Admit:

• Eaten? 9pm night before

• Current meds

• When last on heat

• CPR status

• Confirm details and procedure

 

Patient Discharge:

• Visual: Clipping sites, tattoo

• May not eat much post-op and lethargic

• Cone and reduced activity 14days

• Incision site and wound care

• Sutures out 10-14days

Cleaning and Maintenance of Surgical Instruments

Preparing and Sterilising Surgical Packs

Clipper Care and Maintenance

Rebreathing 02 Flow Rates

Preox; 200mls/kg/min

Induction: 100mls/kg/min

Maintenance: 50mls/kg/min

Breathing Bag Size

5-6 x bw x 10-20 TIDAL VOLUME

ECG Trace

P: atrium contract / depolarising

QRS: ventricular contract / depolarising

T: refilling/ repolarising

ECG: only tells us heart is working - not that its doing well

ETC02 Trace

- top = expiratory pause, bottom - inspiratory pause - inspired CO2 = 0

Hypercapnia: breathe for patient = temporary fix

1. Check patient depth - too deep - central eyes, no jaw tone, no palpebral reflex - not exhaling enough - hypoventilation

 

Too light: central, palpebral, jaw tone, Hyperventilation = hypercapnic

Good plane: ventromedial, no blink or jaw tone

Patient Parameters

80-140 small dog

60-120 large dog

140-200 cat

10-20 rr

100-120 systolic

60-80 MAP

60-80 diastolic

35-55 asleep ETCO2

96+ SPO2

37.5-39 temp

Anaesthetic Problem Solving: Hypotension (MAP 45) and Bradycardia (37)

1. Check patient - too deep = lighten up

2. Atropine - hr too low, if was in 50s use glyco - takes a  few mins

ANTICOLINGERIC

Anaesthetic Problem Solving: Bradycardia but MAP 85

• DON’T DO ANYTHING, MAP good so still perfusing

Anaesthetic Problem Solving: Hypotensive, hr 88

Check depth: if good depth —>

• Fluid bolus: 10ml/kg twice for dog, 5ml/kg twice for cat - over 10-15 mins - won’t work if normovolaemic - only diluting blood volume - increasing volume, ONLY WORK IF LOSING FLUID- replenishing volume

• Increase contractility - dopamine

• (DEPTH - FLUIDS - DOPAMINE)

Anaesthetic Problem Solving: Hypertensive (MAP: 108), Bradycardic (35)

Okay as this is expected

Phase 1: must reverse first before anticholinergic - otherwise too much pressure on heart (vasoconstricted), can give anticholinergic in phase 2 - vasodilation

Reverse with atipamezole - open up the blood vessels, dropping the MAP and allowing the heart rate to safely rise on its own.

*won't get bradycardia if not vasoconstriction 

So if get high hr can assume no vasoconstriction and hypotension is occurring