Anaesthesia Complications (Risk factors (Signalment; age, species, breed,…
Inhibition of thermoregulatory centre by pharmacological agents. Interthreshold range (where body does not initiate thermoregulatory mechanisms) increased from +/- 0.2 degrees to +/- 4 degrees.
Impaired CVS function relating to reduced CO from bradycardia and vasodilation
Heat losses from intubation, open wounds, extremities
Inhibition of thermoregulatory behaviours to maintain body temperature such as shivering and curling into a ball.
Blood loss, wound flushing
High SA:V ratio in small animals increases rate of heat loss
Wrapping of extremities with bubble wrap or foil
Heat pad or hot water bottles
Warm ambient temperature
Premedications: ACP, opioids, a2
Induction agents: propofol, alfax, thiopentone
Maintenance agents and volatile GA
Obstruction from blood, mucus, kinked ET tube, laryngospasm (cats)
Recumbency, atelectstasis, heavy/distended abdominal viscera, thoracic trauma, pleural space disease, deep chested animals
Venous admixture - blood passing from right hand side of circulation (blue blood) to the left (red) without being oxygenated. Due to anatomical shunts, diffusion defects, V/Q mismatch, atelectasis, compression of lungs by abdominal viscera, recumbency etc.
Abnormal breathing patterns
Progressively deeper, and sometimes faster, breathing followed by a gradual decrease that results in a temporary stop in breathing (apnoea).
Deep, gasping inspiration with a pause at full inspiration followed by a brief, insufficient release.
Gasping, laboured breathing, accompanied by strange vocalizations and myoclonus
IPPV (intermittent positive pressure ventilation)
Look at HR and BP and treat underlying cause
Change position on table to allow better lung perfusion
Reduce isoflurane if animal is deep enough
Turn up oxygen
Check isoflurane, anaesthetic machine, hoses, valves, soda lime, ET tube (check not in bronchus)
Check pulse, BP
Check for aspiration of GIT contents
Check ET tube placement and fit
Vasodilation fom ACP, alfax, iso
Bradycardia from a2, opioids, iso, alfax
Reduced contractility from isoflurane
Reduced baroreceptor sesnitivity from Iso, Alfax
Position, abdoinal distension
CVS disease - reduced contractility, arrhythmias, bradycardia
Is animal too deep?
Turn down isoflurane
IV morphine for balanced anaesthesia
Increase vasoconstriction with B1 agonist such as phenylephrine, noradrenaline or dopamine.
Use positive inotrope (B1 agonist) to increase contractility such as dopamine or dobutamine
Give fluid bolus 10mL/kg over 10 min
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Check monitoring equipment to ensure reading is accurate
Signalment; age, species, breed, genetics
Surgeon skill, fatigue and efficiency
Current disease & medications
Lack of pre-anaesthetic examination
Length of procedure