6. Monitoring Anaesthesia Flashcards
Why do we monitor patients?
Monitoring is key to improve patient safety and allow early detection of any individual adverse reactions during general anaesthesia
Monitoring records are legal documents and should not be altered or falsified (fitness to practice)
Monitoring includes the patient, but also includes the equipment that is being used during the procedures
What senses can we use to monitor patients?
Sight- MM colour, surgical site, eye position and pupil size, movement
touch- pulse, CRT, corneal reflex, skin temp, muscle relaxation
hearing- abnormal noise, cardiac auscultation, pulmonary auscultation
What is ‘capnometry’?
the measurement and numerical display of the CO2 concentration in the respiratory gas during the whole respiratory cycle (inspiration and expiration)
What is a ‘capnogram’?
the continuous graphical display of the measurements which produces typical curves
What is ‘capnography’?
the technique (instrument) used
What would you hope to see during a capnogram?
The PECO2 (expiration)level should be between 35 and 45 mmHg - for all species, conscious animals
The PiCO2(inhalation) level, should be at or very close to Zero
Why is a decrease in CO2 during a capnogram concerning?
CO2 is the stimulus to breathe, if it dips there is a problem
- cardiovascular collapse, patient disconnection of breathing system, pulmonary embolism
What is a pulse oximetry?
Device that allows non-invasive measurements of the saturation of haemoglobin with oxygen (SPO2)- clips to the tongue or prepuce
Computer analyses the total absorption of the light and detects the pulsating component of the absorption that originates from arterial blood in the tissue
What do wee monitor when looking at blood pressure?
Diastolic, Systolic and the mean
Which systems do we monitor when looking at the regulation of arterial blood pressure?
- Nervous (impulses from periphery)
- Renal (ECF and renin volume)
- Endocrine
- Local (vaso constricors/dialtors)
What non-invasive methods are there for taking blood pressure in small animals?
- Oscillometric – automated
- Doppler – manual
Both methods are based on the occlusion of blood flow to an extremity by the inflation of a cuff and detection of blood flow during deflation
What are the normal arterial blood pressure values in dogs?
- Systolic- 90-140
- Diastolic- 50-80mmHg
- Mean arterial pressure (MAP)- 60-100mmHg
(Williamson and Leone 2012)
What are the normal arterial blood pressure values in cats?
- Systolic- 80-140mmHg
- Diastolic- 55-75mmHg
- MAP- 60-100mmHg
What is direct arterial BP?
typically done in equine or high risk SA patients- putting a catheter in a peripheral artery which is connected to a pressure transducer
shows a continuous reading of BP and shows the pressure waveform
What is blood gas analysis?
Taking arterial blood to measure blood pH, PP of O2 and CO2, plasma bicarbonate, base excess
Requires automated equipment although handheld is becoming more common
why is blood gas analysis useful?
- Management of critically ill patients
- Management of patients with ventilatory problems
- Management of equine patients in equine hospitals
- Allows specific management of patients
What is electrocardiography?
Three electrode system usually used in veterinary medicine
In the dog and cat normally placed on the left and right forelimbs and the left hindlimb
Provides information limited to electrical activity of the heart
Does not provide any information on haemodynamic function
Allows quick diagnosis of arrhythmias and the type of cardiac arrest
Which respiratory monitors can we use?
Respiratory rate counters (most common) , Airway Pressure Gauges, Spirometers
Why is monitoring temperature important?
Important to detect hypothermia, which can lead to:
- Reduced cellular metabolism
- Decreased anaesthetic requirements (overdose)
- Delayed recovery
- Bradycardia
- Increased morbidity
How do you monitor the depth of anaesthesia?
- Eye position – central vs rotated
- Palpebral reflex – + vs -
- Jaw tonicity – + vs -
Movement – possible vs absent - Cornea – moist vs dry
- HR and RR
- Response to surgical stimulation
