Cases studies/specific conditions Flashcards
List the airway abnormalities that may be present in a brachycephalic dog
- stenotic nares
- elongated soft palate
- everted laryngeal saccules
- laryngeal collapse
- hypoplastic trachea
list other (non airway) structural/functional abnormalities that may be present in the brachy dog
- Obesity –> decr. FRC
- Hiatal hernia (risk) dt low lower oesophageal sphincter tone
- Cor pulmonale
- Eyes - exophthalmus –> corneal ulcers
- GIT ulcers
- Inc. vagal tone –> bradycardia
- Chronic hypercapnia leading to reliance on O2 levels to drive ventilation (may not breathe on 100% O2)
- Increased RBC count
- Increased risk of regurg
considering brachy abnormalities - outline aspects of preparation that will be essential to reduce complications in these patients
- Hypoxaemia –> pre-ox
- Hyperthermia –> cool and let settle
- Risk regurgitation –> antiemetics (maropitant, metoclopramide) + PPI (omeprazole) +/- erythromycin + late extubation (and prep. for reintubation/suction)
- Hypoventilation –> prepare to mechanically/manually ventilate
- Exophthalmus –> lube + positioning
- Hypoplastic trachea –> 5 ETT sizes
- GIT ulcers high risk –> no NSAIDs
- Obesity –> lean dosing/TV if mechanically ventilating
what are the advantages and disadvantages of premeding w/ a tranquiliser (ACP) in brachys
- Advantages: calm induction and recovery —> minimising agitation and assoc. increased RE, dynamic airway collapse can be minimised
- Disadvantages: heavy sedation may lead to recumbency, relaxation of URT muscles and increased risk of obstruction, reduce lower oesophageal sphincter tone and increase risk of regurg.
pros and cons of opioid premed in brachys
- Pros:
- analgesia, assist w/ calm controlled recovery
- anti-tussive (butorphanol) - Cons:
- at high doses risk of bradycardia + resp depression
- panting (methadone)
- risk of vom (morphine)
advantages and disadv. of propofol induction of brachys
- Advantage:
- short acting agent that can be titrated to effect
- mostly smooth, rapid and complete recoveries - Disadvantage:
- apnoea and hypotension if given too quickly
- short DOA - not MAC sparing for long
pros and cons of alfaxalone to induce brachy
- Advantage:
- short acting agent that can be titrated to effect
- mostly smooth, rapid and complete recoveries - Disadvantages:
- apnoea and hypotension if given too quickly
- some evidence of agitate recoveries in lightly sedated dogs
outline warming considerations in brachys
- prevent hypothermia
*care not to overheat; panting can lead to airway irritation and dynamic airway collapse in post-op period
what two opioids DOA is extended in patients with renal disease?
morphine and pethidine because their active metabolites rely on renal excretion
how does feline CKD affect Ketamine?
- cats rely on renal excretion of ketamine –> DOA of ketamine is prolonged
- ketamine can induce catecholamine release through stim. of SNS –> may lead to changes in renal vascular resistance and possible affect GFR
benefits of dopamine use in kidney disease patients
low dose 1-3ug/kg/min targets dopamine receptors
- cardiac receptor affects to maintain MAP
+/- renal effects: renal arteridilation + inc. renal blood flow
how may mannitol support the renal system?
- induces osmotic diuresis (Caution - make sure hydrated)
- causes renal arteriole dilation
- scavenges oxygen free radicals
why is the use of alpha-2 agonists controversial in animals with renal disease?
- may decrease renal blood flow (+ in combo w/ propofol) but GFR is still maintained
- wide BP variation and dec. CO –> use cautiously
considerations for patient w/ DCM
- Increased afterload may lead to regurgitation through incompetent valves: avoid XS vasoconstriction (stress/pain/ketamine/medetomidine)
- Pain will increase cardiac work - opioids important - start at lower end to avoid XS bradycardia
- Avoid Bradycardia: bradycardia increases filling time and thus LV end-diastolic V, this can lead to chamber dilation and worsening of the valvular regurgitation. Avoid medetomidine and high doses of opioids.
- Small decreases in afterload via vasodilation can help forward flow: acepromazine, isoflurane
considerations for patient with aortic stenosis
- Avoid drugs that decrease HR
- medetomidine best avoided; however when tranq. required to prevent stress - use small doses
- opioids essential for pain management - but minimise bradycardia w/ lower doses, short acting CRIs (fentanyl, remifentanil) or glycopyrrolate to offset decrease in HR assoc. w/ opioids - Unable to adjust stroke volume in presence of relative of absolute stenosis
- avoid long acting vasodilators (ACP)
- ensure normovol
- use MAC sparing to decrease inhalant dose - Avoid inc. in HR and SVR
- ketamine and medetomidine are best avoided. (low dose)
