Airway Monitoring Principles Flashcards
Who is responsible for anaesthesia of a patient?
Veterinary Surgeon
Nurses help but not responsible
What are the aims of anaesthesia monitoring?
Maintain Tissue perfusion
Detect problems before they get out of control
Keep patient as close to physiological norms as possible
To prevent patient responding to surgery - nociception
Why do we use anaesthetic charts?
Legal clinical record
Used to spot trends
Able to detect worsening of subclinical disease
Useful handover tool if switching over
All patients are different - case by case basis
MUST RECORD WHAT IS NORMAL FOR PATIENT BEFORE ANAESTHESIA SO HANDOVER PERSON KNOWS
What is tissue perfusion?
Process in which an adequate supply of oxygenated blood and nutrients are delivered to tissues and waste products are removed
This allows normal metabolism
Why is tissue perfusion important?
Allows for normal metabolism
Improves patient outcome
Prevents worsening of subclinical disease
How does anaesthesia affect tissue perfusion?
Anaesthesia often decreases a patients ability to maintain sufficient tissue perfusion
Many anaesthetic drugs have negative effects:
Cardiac depression
Respiratory depression
Decreased homeostasis
For effective tissue perfusion you need a fully functioning cardiovascular-pulmonary system
How are kidneys affected by decreased tissue perfusion?
For kidney issues to show up in blood results there must be 65-70% kidney damage
Therefore we presume a patient is running on 30% kidney function
If we don’t do everything we can to maintain tissue perfusion, we risk pushing the 30% function down to reversible variation or irreversible damage
What factors affect tissue perfusion?
Factors affecting Blood Flow
Factors affecting Oxygen Levels
What causes reduced blood flow?
Low HR
Low BP
Haemorrhaging
Anaemia
What causes reduced Oxygen Levels
Low RR
Shallow breathing (hypoventilation)
Oxygen delivery (equipment failure)
Low HR
Pulmonary disease
Obese patients in dorsal recumbency
Reduces tidal volume
Causes high pressure on diaphragm
What are the three ‘Hypos’
Hypotension - Low blood pressure
Hypothermia - Low body temperature
Hypoventilation - Shallow breathing
Hypotension vs hypovolaemia
Hypotension - low blood pressure
Hypovolaemia - low blood volume (leads to hypotension)
What is cerebral depression?
Reduction in hindbrain function
Causes reduced heart and lung functions:
Blood pressure
Resp rate
Cardiac output
Heart rate
In anaesthesia we want to depress cerebral consciousness but maintain hindbrain function
It is important a patient doesn’t become too deep and cause hind brain depression
How can we establish depth of anaesthesia?
Jaw tone
Palpebral reflex
Eye position
Capnography
Other methods:
Respiration rate
Tidal volume
Heart rate
Blood pressure
Cardiac output
Jaw tone
Ideally relaxed/loose
Brachycephalic dogs often maintain some jaw tone
Ketamine increases muscle tone - unreliable assessment
