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Flashcards in TV4002 Deck (47)
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1

What are the common complications of anaesthesia?

  • Machine / circuit leaks
  • Rebreathing
  • Barotrauma
  • Hypo/hyperthermia

2

What is the cause, consequence, recognition and treatment for a machine leak?

Cause: faulty / damaged equipment, human error

Consequence: environmental pollution, ineffective delivery of fresh gas, inability to ventilate the patient adequately 

Recognition: reservoir bag doesn't stay fullm smell inhalant, hear hissing noise, inabiliy to ventilate the matient effectively, patient problems (inadequate depth, rebreathing)

Treatment: Regular maintenance of equipment, pressure checks, tape (temporary)

3

What is the cause, consequence, recognition and treatment for rebreathing?

Cause: increased dead space, CO2 allowed to accumulate

Consequence: hypercapnia, inadequate depth, hyperventilation, acidosis, sympathetic nervous stimulation 

Recognition: hyperventilation, brick red mm, mild hypertension, inadequate depth, hypoxia, ETCO>55mmHg, inspired CO2 >0mmHg (capnograph will not return to baseline)

Treatment: correct inciting cause, support ventilation IPPV, administer O2

4

What is the cause, consequence, recognition and treatment for barotrauma?

Cause: outflow obstruction (pop-off valve closed, O2 flush, overzealous IPPV, innappropriate inflation of ET tube cuff)

Consequence: gas accumulation, ventilatory impairment, death

Recognition: distended reservoir bag, apnoea, pallor, cyanosis, hypotension, subcutaneous emphysaema

Treatment: relieve outflow obstruction, supplement O2, relieve pneumothorax via thoracocentesis, support circulatory function (IC fluids +/- positive inotropes)

5

What is the cause, consequence, recognition and treatment for hypothermia?

Cause: body temp below 37oC

Consequence: progressive decline in cardiovascular, renal and liver function, impaired coagulation, changes in acid-base

Recognition: rectal or oesophageal temperature probe, 

Treatment: prevent heat loss, passive and active thermal support

6

What is the cause, consequence, regonition and treatment for hyperthermia?

Cause: overheating (drug reaction / malignent hyperthermia)

Consequence: increased metabolism, denaturation of proteins

Recognition: rectal or oesophageal temperature probe

Treatment: cool environment, fan, alcohol / water application, cool IV fluids

7

What are the four components of barotrauma?

  1. Barotrauma - high pressure
  2. Volutrauma - overextension of alveolar regions due to high volume 
  3. Atelectrauma - continuous alveolar collapse and opening, shear force injury
  4. Biotrauma - mechincal stimulation of alveoli releases inflammatory mediators

8

What are the causes of and treatments for bradycardia?

  • too deep - reduce depth
  • drug effect (alpha 2, opioid, propofol)
  • hypothermia - warm the patient
  • vagal stimulaion (GI tract, etc) - atropine
  • hyperkalaemia
  • hypertension - deepen anaesthesia + analgaesia
  • increased ICP - IPPV, mannitol / furosemide
  • Late stage hypoxamia

 

9

What are the causes of and treatments for tachycardia? 

  • Light anaesthesia - increase depth
  • Strong stimulation (sympathetic reflex)
  • Drugs (atropine, ketamine) - wait to wear off
  • Hypercapnia - IPPV oxygen
  • Hypovolaemia / hypertension - fluid therappy + positive inotrope
  • Hyperthermia - cool the patient
  • Early stage hypoxaemia - IPPV oxygen

10

What are the causes of and treatments for arrhythmias?

  • inadequate anaesthetic depth - deepen
  • arrythmogenic drug (medetomidine)
  • hypercapnia - IPPV
  • hypoxaemia - IPPV
  • hypovolaemia / hypotension - fluid therapy
  • hypothermia - warm patient
  • acid-base / elecrolyte imbalance - correct imbalance
  • myocardial disease / injury

11

What are the causes and consequences of hypotension?

Cause: anaesthesia induced CV depression, excessive anaesthetic depth, hypovolaemia, intraoperative haemorrhage, arrhythmia, organ manipulation, IPPV

Consequence: arrhythmias, acute renal failure, post-anaesthetic myopathy, blindness, gut-barrier failure, sepsis, death

12

What are the clinical signs of blood loss?

  • pale mm
  • prolonged CRT
  • hypotension
  • apparent increase in anaesthetic depth

13

How can you determine how much blood loss has occurred?

Calculate:

  • each gauze swab holds 5-10ml of blood
  • lap sponges hod 50-100ml of blood

14

What causes a flatline capnograph and how do you treat it?

  • Caused by complete airway obstruction
  • Treatment:
    • check that curcuit is still connected
    • extend the head and neck to relieve kinks
    • adjust ET tube cuff
    • suction the ET tube
    • provide supplemental O2
    • extubate and reintubate with new ET tube if needed

15

What causes rebreathing in each type of system?

Both: increase in death space

Non-rebreathing: Inadequate flow rate

Rebreathing: exhausted CO2 adsorbent, malfunctioning one-way valve

16

What are the five reasons for hypoxaemia?

  1. Low inspired O2
  2. Hypoventilation
  3. Diffusion impairment
  4. V/Q mismatch
  5. Shunt

17

What are the four resona for hypoxia?

 

(inadequate oxygen reaching the tissues)

  1. hypoxaemia
  2. reduced delivery capacity of O2
  3. circulatory problem
  4. cytotoxic / histotoxic (cell utilization of O2 inhibited)

18

How does small animal anaesthesia differ from the horse?

  • ETCO2 can be significantly different from PaCO2 due to large dead space 
  • PaO2 may be lower than expected with 100% oxygen due to presence of large shunt
  • Min MAP required >70mmHg to perfuse compartmented and compressed muscles
  • Eye signs are less reliable in horses - muscle tone of the neck may be a good indication

19

What are anaesthetic risk factors that create a  'compromised' patient?

  • perioperative health status
  • increasing age
  • weight extremes
  • procedural urgency

 

The very young, old, sick or injured

20

How does acidosis affect the activity of thiopentone?

Acidosis increases unionised thiopentone passing through the cell membrane and reduces the protein bound fraction, thus increasing the active component of thiopentone

21

What diagnostic methods can be used to determine lung injury?

  • Radiography
  • Auscultation
  • Thoracocentesis

22

Why is stabilisation of a compromised patient important before anaesthesia?

  • cannot tolerate anaesthesia well, very high risk
    • hypovolaemia
    • acid-base imbalances
    • thoracic injuries
    • pain!
  • stabilisation will improve vital organ function

23

What are the key factors for a sucessful outcome of anaesthetic of the compromised patient?

  • Prepare and anticipate complications
  • Monitor and support patient through the anaesthetic and post-operative period
  • Early detection of abnormalities
  • Pain free
  • Well managed vital organs

24

What is the definition of paediatric?

Less than 12 weeks of age

25

What is the definition of geriatric?

Last 20-25% of expected natural lifespan 

Animals >7 years old at JCU

26

What are the important physiological characteristics of the paediatric CNS?

  • highly permeable BBB
  • immature sympathetic nervous system - reduced ability to increase myocardial contractility and reduced vascular tone
  • immature baroreceptor reflex
  • fully developed pain perception

27

What are the important physiological characteristics of the paediatric cardiovascular system?

  • generally lower BP, SV and perivascular resistance
  • minimum cardiac reserve 
  • CO can only be increased by rapid HR 
  • therefore, unable to compensate for significant fluid loss

28

What are the important physiological characteristics of the paediatric respiratory system?

  • high metabolic rate - high oxygen demand - high RR
  • weak chest muscles, higher airway resistance - ventilation is less efficient
  • high risk of hypoxaemia and rebreathing

29

What are the important characteristics of the paediatric hepatic system?

  • Immature at birth
  • Minimum glucose storage and regulation
  • Slower metabolism
  • Reduced production of protein
  • Matures 8-12wks
  • Puppies: Elevated ALP and GGT
  • Kittens: Elevated ALT

30

What are the important physiological characteristics of the paediatric renal system?

  • immature at birth
  • GFR and tubular excretion increases with age
  • low BUN and creatinine
  • less able to concentrate urine
  • mature 8-12 wks
  • cannot compensate for hypovolaemia / overhydration

31

What are the important characteristics of paediatric body composition?

  • 80% water (compared to 60% in adults)
  • small fat store
  • PCV declines from birth (50%) to 29 days old (30%) and then increases up to 6months
  • High distribution of cardiac output to vessel rich tissue (heart and brain)

32

What are the important physiological characteristics of the geriatric CNS?

  • decrease in cerebral perfusion, Oconsumption and brain weight
  • decrease in neurotransmitters
  • change in pharmacokinetics
  • reduction in MAC
  • increased sensitivity to drugs

33

What are the important physiological characteristics of the generiatric cardiovascular system?

  • decrease in blood volume, blood pressure, cariac output and baroreceptor activity
  • increase in circulation time and vagal tone
  • thickened / calcified vessel walls 
  • decreased ability to autoregulate blood flow and less cardiac reserve

34

What are the important physiologic characteristics of the geriatric respiratory system?

  • decreased lung capacity, O2 consumption and O2 diffusion capacity
  • rigid thoracic wall with low cmpliance lung and weaker repiratory muscles
  • less efficient ventilation 
  • loss of protective airway reflexes

35

What are the important physiological characteristics of the geriatric hepatorenal system?

  • reduction in liver mass - reduced function
  • decreased renal and hepatic blood flow - loss of nephrons and impaired distal tubular function
  • reduced ability to cope with hypovolaemia / overhydration 

 

36

At what age does a puppy / kitten attain adult organ function?

12 weeks

37

What are the fasting recommendations for paediatric patients?

milk - 30 minutes

solids - 2-3 hours

38

What are the fasting recomendations for geriatric patients?

Fast overnight but allow free access to water

39

What are the important physiological characteristics of the prenant patient cardiovascular system?

  • CO increases 30-40% (due to HR) = to meet O2 demand from placenta and foetus(es)
  • Blood volume increases - RBCs increase - low PCV and TPP
  • Therefore, stress for pregnancy may predispose pre-existing cardiac disease to cardiac failure
  • Maintain CV function!

40

What are the important physiological characteristics of the prenant patient respiratory system?

  • O2 requirement increases by 20-25%
  • Increased VM from both VT and RR
  • Reduced lung volume and FRC due to pregnant uterus - predisposed to hypoxaemia and faster change in depth
  • Increased VM - reduced PaCO2
    • Vasoconstriction
    • Left shift oxyhaemoglobin dissociation curve: less effective unloading of oxygen to the foetus
  • Pre-oxygenate!

41

What are the important physiological characteristics of the prenant patient CNS?

  • Increased venous volume in epidural space - reduced volume
  • Reduction in MAC up to 40%, increases sensitivity of injectable drugs and local anaesthetics: due to progesterone +/- endogenous opioid
  • Low dose! Dose to effect!

42

What are the important physiological characteristics of the prenant patient GI and hepatorenal systems?

  • Reduced GI motility, gastric emptying and lower oesophageal sphincter tone
  • Fasting? 56% of maternal deaths following caesarean section due to pneumonia
  • Increased ALP, AST, ALT and LDH
  • Increased renal blood flow: reduction in BUN and Creatinine
  • Quick induction and secure the airway!

43

What are the important physiological characteristics of the pregnant patient's placenta?

  • Uterine blood flow is not “auto-regulated” = it is dependent on the uterine arterial to venous pressure gradient and uterine vascular resistance
  • Therefore, maternal hypotension, hypovolaemia or fear and/or pain will impair placental perfusion and such it is very important to maintain maternal blood pressure and oxygenation

44

What can you give a neonate at caeserian if opioids were given to the mother as premediation?

Drop of naloxone under the tongue

45

WHat can you give to neonates at caeserean if benzodiazapam was given to the mother as part of premed / induction?

Flumazenil

46

What is your anaesthetic protocol for caeserean section in small animals?

  • General anaesthetic
  • IV injectable induction (propofol/alfaxolone)
  • Maintain on isoflurane/sevoflurane
    • Assisted ventilation or IPPV
    • Light plane of anaesthesia until delivery
    • Close monitoring

47

How can you detect pain in cats and dogs?

  • abnormal behaviour 
  • physiological change: HR, RR
  • pain scale and scoring systems