Support and Monitoring the Anaesthetised Patient Flashcards
1
Q
Not 6 things which should be recorded in the monitoring record (legal document)?
A
- Fill in details before you start
- Record exact mg of drugs given
- Assess risk for patient
- Record as many parameters as possible
- Note events occurring
- Assess recovery and analgesia
2
Q
What are the two reasons we support our patients?
A
- influence of outcome
2. ethical considerations - they are relying on us
3
Q
Name 10 things we should be monitoring as part of basic anaesthesia monitoring?
A
- muscle relaxation
- neck muscle tone (especially horses)
- eye rotation
- pupil changes
- jaw tone (different for each patient)
- Whisker/ pedal reflex
- Anal tone (reliable in horses)
- Mucous membrane colour
- CRT
- Toe-web/ core temperature
4
Q
Name 4 things you would monitor with pulmonary monitoring?
A
- breathing rate, rhythm, nature and effort
- observe bag and chest excursions
- ventilometer or respirometer if available
- mm colour
5
Q
what can be used to show if ventilation is within acceptable limits?
A
Spirometry
6
Q
What is the normal minute volume?
A
100-300mg/ml/kg
7
Q
What is the normal tidal volume?
A
7-10ml/kg
8
Q
What two methods are superior for assessing function of respiratory system?
A
Blood gas analysis and capnography
9
Q
What is the dead space?
A
This is the amount of space that is not involved in the exchange of gases.
10
Q
Delivery of oxygen means what?
A
How much oxygen is being delivered to the tissues by how much blood pressure
11
Q
How do you work out CaO2?
A
SaO2 x Hb x 1.34 + (0.003 x PaO2)
12
Q
Name 4 things that we can measure to get an idea of the delivery of oxygen?
A
- CaCo2
- MAP
- Respiratory
- Cardiovascular
13
Q
3 methods to measure respiration?
A
- oesophageal stethoscope
- capnograph
- pulse oximeter
14
Q
Name 3 methods to measure cardiovascular?
A
- ECG
- Blood pressure
- Pulse
15
Q
What is Heffner’s constant?
A
It is 1.34 and is the number of molecules attached to haemoglobin.
16
Q
Name 2 limitations to pulse oximetry?
A
- low heart rates/ extremely high heart rates- not picked up
- probe design.
17
Q
What is a massive advantage of pulse oximetry?
A
Early warning - cyanosis is a crude estimation
18
Q
What happens to the blood pH if there is less oxygen?
A
decreases
19
Q
What should PaO2 at normal room saturation?
A
100
20
Q
What can PaO2 go up to one 100% oxygen?
A
500
21
Q
If the patient is going blue from cyanosis, what does this mean?
A
The patient is very de-saturated.
22
Q
How does pulse oximetry work?
A
Probe (transmitter and reciever or IR and red light), transilluminates a pulsatile arteriolar bed.
computer analysis absorption of light.
23
Q
What happens if the oxyhaemaglobin or haemaglobin are not carrying oxygen?
A
There is more red light and IR absorption.
24
Q
What is methaemaglobin?
A
Cannot bind oxygen therefore more red light absorption.
25
What is the reading on a pulse oximeter telling us?
The ratio of haemaglobin and % oxygen saturation.
26
How is the haemoglobin saturation SPO2% (from pulse oximeter) related to the PaO2 of the blood?
Oxygen content is dependent on both PaO2 and SPO2.
Oxygen content = SPO2 x Hb x 1.34 + (0.003 x Pa03)
27
On an oxygen-haemaglobin dissociation curve, what does a shift to the right represent?
A decreased affinity for oxygen to bind to haemaglobin.
28
Name three factors which decrease an oxygen's affinity for haemoglobin?
1. decreased pH
2. increased DPG (moves O2 from red blood cells to tissues)
3. increased temp
29
Name three factors which will increase oxygen's affinity for Hb?
1. increased pH
2. Decreased DHP
3. Decreased temp
30
Name 4 things that blood gas analysis can monitor?
1. pH
2. HCo3
3. PCo2
4. Po2
31
Which is the most accurate device for measuring oxygen content and what is a good alternative?
Blood gas analysis is the most accurate, however capnograph is a good alternative (PaCo2)
32
Why is pulse oximetry, especially in anaemic patients?
Because, whilst the Hb content of 15g/dL and PCV 45%, cyanosis might start to manifest at about SaO285% with no other clinical signs.
HOWEVER in an anaemic patients, Hb 9g/dL and PCV of 27%, cyanosis might not manifest until about SaO2 73% therefore this is dangerous!
Need pulse oximetry to pick up desaturation early.
33
Which three stages will require supportive oxygenation?
1. during ALL anaesthetics (even if just IV)
2. pre-induction e.g. masks
3. Recovery (high risk surgery)
34
Name three methods to increase Fraction of Inspired Oxygen (FIO%)?
1. Intranasal
2. Intratracheal (post-op horse)
3. Tracheostomy (emergency)
35
Which sites should you use to monitor pulse rates?
Peripheral pulse - early warning.
36
Name 5 sites where you can monitor pulse rates?
1. femoral artery
2. dorsal metatarsal artery
3. lingual artery
4. Auricular
5. compare the femoral and dorsal metatarsal
37
With hypotension, which pulse disappears?
Dorsal metatarsal
38
Which is not a good artery in terms of monitoring subtle changes?
Femoral, therefore good comparison.
39
Name two further arteries which can be monitored in a horse and dogs?
Facial artery in horses and lingual artery in dogs.
40
name 4 methods of arterial blood pressure monitoring?
1. Non-invasive blood pressure monitoring (NIBP) e.g. sphyngmomanometry, Oscillometric
2. Doppler
3. Invasive blood pressure monitoring
4. Finger on pulse (DO NOT DO THIS - systolic 90-150 feels the same)
41
How does doppler work?
Piezoelectric crystal placed over artery (clip fur off, use gel)
42
Where is the cuff placed in relation to the doppler probe?
Proximal
43
Which pressure does doppler measure?
Systolic pressure only.
44
How do you use Doppler?
Inflate the cuff until there is no longer any sound and then deflate and when you can hear sound again, that is the systolic pressure.
45
In what species is oscillometry unreliable?
Dogs and cats
46
why is oscillometry not used very much?
It is expensive and other methods are more accurate
47
Name two advantages of oscillometry?
Can cope with high HR and poor perfusion.
48
What does oscillometry measure?
systolic,mean and diastolic pressures.
49
Name a method of invasive blood pressure monitoring?
1. artery cannulation
50
Which three arteries can be used for artery cannulation?
1. auricular
2. dorsal pedal
3. facial arteries.
51
What does artery cannulation measure?
systolic, mean and diastolic blood pressures.
52
What must you do if you leave in an artery cannulation for blood pressure monitoring?
Label it and not inject any other drugs!
53
What should the artery cannula be like and why?
Narrow and non-compliant to amplify the signal.
54
How can we monitor CVP (central venous pressure)?
Long jugular catheter
55
What does CVP indicate?
The filling of the heart
56
What is CVP affected by?
Contractility and circulating blood volume.
57
When is CVP usefu?
When using fluid therapy
58
what does an increased CVP mean?
failing heart or volume overload
59
what does a decreased CVP mean?
haemorrhage, blood pooling or inadequate fluid therapy.
60
How do we record CVP?
As a trace.
61
Normal manometer reading of dog?
0-10cm
62
Normal manometer reading of cat?
0-5cm
63
How to we monitor heart rhythm?
Continuous ECG
64
Why is ECG often distorted?
Due to patient position
65
Which triangle is normally upside down because of this?
Einhoven's triangle.
66
Name another more advanced monitoring method of cardiac output?
Flow parameter.
67
What does flow parameter tell us?
Indicator of perfusion rather than pressure.
68
What is cardiac output?
Stroke volume x Heart rate
69
What could you use to measure cardiac output?
Inject lithium on venous side and measure on arterial side
70
What is a good measure of anaesthesia and what does it measure?
Capnography - measures Co2.
71
What is the pattern on a capnograph?
Increase (inhalation), decrease (expiration) pattern
72
Name three things carbon dioxide is measured by?
Infrared, Ramen scatter, mass spectroscopy
73
What is end tidal carbon dioxide?
4.8-5.7% (36-43mmHg)
74
What is the assumption of capnography?
Alveolar carbon dioxide approximates arterial carbon dioxide.
75
Name some reasons for increased carbon dioxide?
Rebreathing, exhaustion of soda lime, changes to depth, changes to dead space, hypoventilation, pyrexia, increased carbon dioxide production
76
Name 6 reasons why there might be a decrease in co2?
THIS IS WORRYING!
1. disconnection (check circuit)
2. Mis-intubation
3. circulatory failure
4. Hypotension
5. cardiac arrest
6. Hyperventilation
77
What does an obstruction look like on a capnograph?
The peaks get smaller and smaller. Could be something like mucus in the tube.
78
What else can we do to measure carbon dioxide?
Take blood samples to measure blood gases. can be arterial or venous.
79
What does cardiac oscillations mean on capnograph?
Means the heart is beating against the lungs and is pushing the co2 out of the lungs
80
what does curare cleft mean on capnography?
This means there is a blockade- maybe anaesthesia too light?
81
what does buckling ventilator mean on capnography?
this means the animal is taking small little gasps.
82
Why do we need to monitor temperature?
because anaesthetised patients cannot regulate their own temperature.
83
Two ways of measuring temperature?
Rectal thermometer or an oesopharyngeal thermoprobe?
84
Name 9 ways to increase an animals temperature under anaesthetic?
1. bubble wrap
2. socks
3. hot water beds
4. lams
5. low flow anaesthesia
6. warm theatre
7. heated pads
8. blankets
9. thermovents/ HME
85
What does hypothermia lead to? 6 things?
1. prolonged recovery
2. decreased circulation
3. decreased metabolism
4. decreased mentation
5. increased pain and analgesia needed
6. increased oxygen demand on recovery e.g. shaking
86
what is the problem with dosing cold patients?
cold patients need less anaesthetic therefore more likely to overdose them.
87
8 reasons temperature falls during anaesthesia?
1. reduced shivering
2. vasodilation -isoflurane
3. reset thermoneutral point
4. behaviour modification
5. open body cavity
6. cold gases
7. dry gases
8. wetting and prep e.g. alcohol
88
Which breathing system supports core temperature?
Circle system (rebreathing)
89
Think of another way temperature could be supported? what does it have to be?
Support of renal function
5x maintenance fluid.
90
What should be the fluid rate for supporting renal function in dogs?
10ml/kg/hour (less for cats)
91
Two ways in which we can monitor collection of fluid?
estimated 1-2ml/kg/hour
measure by volume *collection systems e.g. urinary catheter) and also specific gravity
92
What is a method of monitoring anaesthesia in referral practices?
Neurmuscular blockage (NMBD)
93
What are the three types of peripheral nerve stimulators that we would use to check the blockage?
1. TOF - train of four
2. DBS - deep brain stimulation
3. tetanic stimulation
94
in what kind of surgery would this be used?
ocular surgery, thoracic and facilitating IPPV.
95
Name 5 further laboratory tests which could be used to monitor anaesthetic?
1. PCV and TPP
2. Hb
3. Platelets and coagulation
4. Albumin
5. Lactate
96
How does gastric tonometry work?
Looks at the pressure of the stomach. The higher the pressure, the greater the sympathetic tone therefore adjust the plane of anaesthesia so that it is lower.
97
What are the 4 aspects of minimal support
1. baseline monitoring (oesophageal stethoscope, finger on pulse, ventilation rate and monitoring record
2. fluids and IV access
3. Oxygen
4. Analgesia
98
Where possible, what is beneficial to add to this list?
1. pulse oximetry
2. capnography
3. Temperature
99
Which is the most effective mode of monitoring?
Capnography
