Monitoring Flashcards
Why do we monitor anaesthesia?
Prevent patient nociception to surgical stimulation
To detect abnormalities before they become complications
Maintain tissue perfusion and oxygenation to improve patient outcome and prevent worsening of disease
What do these symbols represent on an anaesthesia chart?
What are the causes of decreased tissue perfusion during anaesthesia?
Decreased blood flow:
- Decreased BP
- Decreased HR
- Haemorrhaging
-Anaemia
Decreased oxygen and nutrients:
- Decreased RR
- Equipment failure
- Decreased HR
- Lung pathologies
- Obesity
What 3 problems always occur (to a certain extent) in anaesthesia?
Hypotension
hypothermia
Hypoventilatino
How can depth of anaesthesia be determined?
Checking jaw tone (solid - light anaesthesia) (brachy breeds often maintain jaw tone)
Positive palpebral reflex = too light
Eye position (rostrally rotated eye = ideal)
capnography
HR
RR
BP
When can eye position not be used to assess depth of anaesthesia?
Ketamine use increases muscle tone so eyes may not rotate
Assess the depth of anaesthesia in this eye
Central eye:
- dilated pupils = too much CNS depression
OR
normal or constricted pupils = potentially too light for surgery
What methods are there to check temp in surgery?
Rectal thermometer
Oesophageal temperature probe
How can cardiovascular system be assessed during surgery?
Heart rate and rhythm
mm colour
CRT
bleeding
BP
haemoglobin oxygen saturation
arrythmias.
What equipment can be used to monitor the cardiovascular system during surgery?
Bp monitors
pulse oximeters
ECG
Stethoscopes
Oesophageal stethoscope
Feeling a pulse to detect deficits
What are the different sites of pulse palpations?
Sublingual (ventral aspect of the tongue)
Mandibular
Digital metacarpal
Digital metatarsal
Dorsal pedal (usually palpable over the dorsum of the metatarsal area)
Femoral (medial aspect of the femur)
Coccygeal artery on the ventral surface of the tail
What does bluish/purple MM mean?
cyanosis - low O2 saturation, severe hypoxaemia
What methods of measuring blood pressure can be used during surgery?
Doppler
Oscillometric
What MAP (mean arterial pressure) is needed to properly perfuse the heart, brain and kidneys?
60mmHg (systolic >90mmHg)
An MAP of <60mmHg for over 30 mins can lead to:
Renal failure.
Delayed recovery
Neuromuscular complications
Decreased hepatic metabolism of drugs
CNS abnormalities such as blindness.
What does pulse oximetry tell us?
Sp02 =% of haemoglobin that is saturated with oxygen (healthy patient should be >95%)
Detects hypoxaemia
Measures pulse rate
Displays a photoplethysmographic (PPG) waveform (“pleth” for short)
What the possible places a pulse oximetry probe can be placed?
Tongue
Nose
Lip
Pinna
Toe web
Flank
Tail
Achilles tendon
Rectum
Vulva
Penis
What are the benefits of pulse oximetry?
Inexpensive.
Non invasive
Well tolerated
Continuous
Automatic
Portable
Audible
User friendly
What are the limitations of pulse oximetry?
Can give inaccurate readings with:
-Vasoconstriction (alpha 2 agonists, hypothermia, shock)
- Hypoperfusion
- Movement
- Hypothermia
- Bright overhead lights
- Smoke inhalation (abnormal haemoglobin)
- Pigmented skin
- Anaemia
- Shock.
Why is it important to use a pulse oximeter with blood pressure monitoring?
A patient may not be hypoxaemic (pulse ox reading less < 95%) but may be hypoxic
How can the respiratory system be monitored?
Respiratory rate, rhythm and effort:
- lungs sounds
- visibly breathing
- capnographs
What equipment can be used to monitor the respiratory system?
Assess adequacy of respiration (EtC02 (end tidal carbon dioxide))
Check or estimate blood gases (O2
and CO2)
What can capnographs be used for in assessing respiratory function?
Monitoring of ventilation in spontaneously breathing anaesthetised patients
Monitoring of patients undergoing mechanical or manual ventilation
Monitoring of patients undergoing CPR
Monitoring of ventilation in intubated coma patients
Confirmation of endotracheal tube placement
Confirmation of naso-oesophageal feeding tube placement
What are the 3 levels of info do we get from capnographs?
Metabolism
Perfusion
Ventilation
Level 1:
- Breathing or not
- Respiratory rate.
Level 2:
- Expired and inspired CO2 levels.
- understand the state of the patient’s respiration i.e. normocapnic, hypocapnic or hypercapnic.
Level 3:
- Waveform profile
What are the normal EtCO2 ranges for cats and dogs?
Dogs - 35-45 mmHg
Cats - 28-45mmHg
What is the main cause of hypocapnia?
Hyperventilation => CO2 is exhaled faster than it is produced
What is the main cause of hypercapnia?
Hypoventilaion => CO2 being exhaled slower than it is being produced
What is EtCO2?
end tidal CO2
Label the diagram
What can blood gas analysis measure?
PaCO2 (partial pressure of carbon dioxide in the blood)
PaO2 (partial pressure of oxygen in the blood)
Blood pH
Electrolytes
Lactate
Others
Label this diagram
Label this diagram
BP readings - oscillometric
Label this diagram
Temp
Why do we assess EtCO2?
