Introduction & Pre-anaesthetic Assessment Flashcards
Apnoea
no airflow for >10 sec
anoxia
absence of oxygen
hypoxia
not enough oxygen content in the tissues
hypoxaemia
not enough oxygen content of the blood
how long does it take for hypoxaemia to affect the brain during anaesthesia? What does it do?
After about 10 mins it can lead to brain injury and cause serious complications
hypercapnia (hypercarbia)
circulating CO2 levels are above reference range so that it causes negative effects
hyperventilation
needs: abnormal RR w/ normal tidal vol, high RR w/ high tidal vol, or normal RR w/ high tidal vol
removal of CO2 faster than the body can produce –> leads to too low of CO2
Low CO2 leads to
vasoconstriction in the brain & brain injury
Hypoventilation
if ventilation is not efficient enough (CO2 accumulates in circulation because lungs are not removing it sufficiently
Will lead to accumulation of CO2 –> when measured, use arterial CO2 by blood gas analysis or measure PPCO2
Increase –> cardiac arrest, etc
Tachypnoea
rapid breathing
bradypnoea
slower than normal breathing
tachycardia
heart beats faster than normal
bradycardia
heart beats slower than normal
hypotension
lower than normal BP
hypertension
higher than normal BP
hypothermia
lower than normal body temp
hyperthermia
higher than normal body temp
tranquiliser
drug used to reduce tension or anxiety
sedative
drug for calming & sleep-inducing effect
anxiolytic
drug used to reduce anxiety
hypnotic
drug used to induce sleep
dissociative anaesthesia
drugs used to distort perceptions of sight & sound & produce feelings of detachment/dissociation from the environment & self
neuroleptanalgesia
combo of potent sedative analgesic & tranquiliser
analgesic
drug used to relieve pain
analeptic
drug that stimulates the CNS
What is the definition of general anaesthesia?
state of unconsciousness produced by controlled, reversible intoxication of the CNS
What are the 3 reasons we use anaesthesia?
- to prevent suffering while doing invasive procedures
- to prevent operator risk
- to fulfill legal requirements
What are the 3 main things done as pre-anaesthetic assessment & screening?
- take a detailed history
- physical/clinical exam
- tests
What are the 4 reasons to assess patients pre-anaesthesia?
- to determine the extent of clinical dz
- to detect subclinical dz
- to assign an ASA category of physical status
- to reduce anaesthetic & surgical morbidity & mortality
What are some signs in the history that may impact your pre-anaesthesia assessment?
- nature & duration of illness & txt received
- exercise intolerance not related to musculoskeletal issues/injuries
- cough
- dyspnoea
- recent trauma
- syncope
- appetite
- time of last meal
- PU/PD
- V/D
- previous anaesthetic Hx
- other: pregnancy, behaviour, seizures, etc
What are some physical exam features that affect anaesthesia that are non-specific to the body systems?
demeanour of the patient
assessment of ‘real’ age (may differ from chronological age)
BCS out of 9
Breed (brachycephalics? sighthound?)
Hydration status
body temp
weight
What physical exam features might you find abnormal in the cardiovascular system that may impact anaesthesia?
- HR, rhythm, murmurs
- femoral pulses
- apex beat/thrills
- mm colour/CRT
When examining the respiratory system prior to anaesthesia, what are you specifically examining?
- observations of the thx
- comparing each side of thx
- count RR
- respiratory pattern
- auscultate both sides of thx
- tracheal ‘pinch’
- mm colour
What other body systems may be impact anaesthesia assessment?
- GI & urinary systems & abdominal palpation
- skin
- neurological system
For a young, non-pediatric, healthy patient (ASA 1 or 2) undergoing a routine Sx, is there a need for extra screening past a thorough clinical exam?
- “Routine haematological and biochemical profiles are unnecessary (and constitute an extra expense) in apparently fit, healthy animals” (1998)
- Additional screening detected changes of little clinical relevance (2008)
What haematology/biochemistry is necessary for patients undergoing major Sx & trauma P’s or pediatric P’s (<6 mos old)?
minimum of:
- PCV, Hgb
- total plasma protein, albumin
- urea & creatinine (+-) iPO4
- ALT, AP (+- bile acids)
- USG & dipsticks
What haematology/biochemistry is necessary in sick patients with an ASA score of 3 or higher?
Full haematology
biochemistry (renal & hepatic incl clotting, electrolytes)
Urinalysis
if there is a suspected disease, you have to test for…
the suspected dz
young animals, diabetics, insulinoma, septic patients require what blood test?
BG q 30-60 minutes
if you have a patient with vomiting & diarrhea, what bloods need monitoring?
electrolytes (K, Na, Cl)
USG
if you have a doberman or doberman cross, what blood tests do you specifically need to consider prior to anaesthesia?
BMBT
von Willebrand factor
What patients may require thoracic radiographs prior to anaesthesia?
- significant cardiac dz
- respiratory dz
- RTA/trauma P
- tumours (esp mammary, splenic, bone)
What patients may require ECG prior to anaesthesia?
- significant cardiac dz, murmur, arrhythmias except sinus
- breeds susc to DCM (Great Dane, St. Bernard, Irish Wolfhound, Newfoundland, Dobermans)
- Cats w/ hyperthyroidism (HCM)
- splenic tumours
- if pulse deficit detected
- sick sinus syndrome in mini schnauzers
- diseases leading to arrhythmias (Hyperkalaemia, GDV, splenic tumour, post-traumatic myocarditis)
When assigning ASA scoring, how do you note that it is an emergency patient?
Assign an E next to the score
What patient gets an ASA 1?
normal, healthy P w/ no discernible organic disease scheduled for an elective procedure
What patient gets an ASA 2?
mild, systemic dz, which does not limit activities
What patient gets an ASA 3?
moderate to severe systemic dz that limits activities but is NOT a constant threat to life
What patient gets an ASA 4?
severe systemic dz that is a constant threat to life
What patient gets an ASA 5?
moribund p, not expected to survive without the operation
