Intra-operative complications Flashcards
Why do complications occur?
Patient factors e.g. species, breed, weight, age
Anaesthetic factors
Procedure factors
What are the 5 common intra-operative complications?
Hypotension Hypothermia Hypoventilation (hypercapnia, hypoxia) Bradycardia Tachycardia
Blood pressure = _ x _ ?
Cardiac output x systemic vascular resistance
Cardiac output = _ x_ ?
Heart rate x stroke volume
Mean arterial pressure must be more than what value to maintain vital organ perfusion?
60mmHg
What are some causes of hypotension?
Reduced CO –> reduced stroke volume, reduced heart rate
Reduced systemic vascular resistance
What can cause a reduced stroke volume?
Hypovolaemia - dehydration
Reduced venous return - dorsal recumbency
Disease - pericardial effusion
What can cause a reduced heart rate?
Drugs
Disease - 3rd degree AV block
What can cause a reduced systemic vascular resistance?
Vasodilation
- Drugs
- Disease: SIRS
How do you go about treating hypotension - in order?
- Check the cuff of the limb and repeat the reading
- Check the plane of anaesthesia and reduce
- Treat HR if it is low using atropine
- Give fluid therapy: crystalloids
- Drugs: vasopressors, positive inotropes
Is hypothermia worse in small or large patients?
Small - larger SA:vol so more likely to lose heat quickly
A body tempo below what is classed as hypothermia?
37 degrees
What are some causes of hypothermia?
- increased heat loss
- reduced heat protection
- abolished behavioural responses
- alterations in hypothalamic function
What can cause increased heat loss during surgery?
- Evaporation from body surfaces (hair clipped, cleaning fluids applied)
- Evaporation from open body cavities
How can hypothermia be prevented?
o Blankets o Bubble wrap o Warm air o Heated mats o Heat and moisture exchanger (HME)
What are some of the main consequence of hypothermia on the body?
- Arrhythmias
- Coagulopathies
- Reduced immune function
- Reduced drug metabolism
- Shivering increases oxygen demand
What are the 2 main consequences of hypoventilation?
Hypercapnia
Hypoxaemia
What is hypercapnia?
Increased level of CO2 in the blood
What are the 2 methods of diagnosing hypercapnia?
Sampling arterial blood
Capnograph
What are the two main causes of hypercapnia?
- Hypoventilation
- Breathing systems inadequate
How can hypercapnia be treated?
- Increase minute ventilation - RR x Tidal volume
- Lighten plane of anaesthesia
- Mechanical ventilation
What are the main causes of hypoxaemia?
- Inadequate oxygen delivery
- Profound hypoventilation
- Impaired gas exchange
- Airway obstruction
What are the 3 main causes of bradycardia?
- Increased parasympathetic system activation e.g. opioids, alpha 2
- Hypothermia
- Disease
Why is bradycardia more of a concern in neonates?
They cannot increase their SV to compensate for the decreased heart rate
What are the main causes of tachycardia?
Pain - increased sympathetic tone
Hypovolaemia
Hyperthermia
Hypercapnia
What causes cardiac dysfunction?
Tachycardia leads to the heart muscle needing more oxygen, but it doesn’t receive it
