monitoring anaesthesia Flashcards
(22 cards)
What are common anaesthetic complications?
- Hypoventilation and Hypoxaemia
- Hypotension / hypertension
- Hypothermia / hyperthermia
- ↓ tissue perfusion
- ↓ CO
- Prolonged / difficult recoveries
- Myopathies / neuropathies
- Others / unknown + unexplainable
- Death
These complications can occur in both healthy and unhealthy patients.
Why is it important to monitor a patient during anaesthesia?
- Ensure still alive
- Patient safety and wellbeing + Personnel safety
- Adequate anaesthesia depth for procedure
- Pre-empt problems
- Identify trends
- Administer other drugs
- Complications can occur in healthy patients
- Individuals respond differently to anaesthesia
- Anaesthetic document = legal document
Monitoring allows for early intervention and reduced complications.
What are the goals of monitoring during anaesthesia?
- Maintain physiological processes as normal as possible
- Early identification of problems
- Monitoring BOTH physiological parameters and depth of anaesthetic
This is crucial to ensure the safety and effectiveness of the surgical procedure.
When should monitoring begin and end?
From start to finish; physical exam to discharge
Particular care should be taken during high-risk times like induction and recovery.
What systems should be monitored during anaesthesia?
- Cardiovascular system
- Respiratory system
- Temperature
- CNS
- Reactions to drugs/agents
- Link to other systems and organ function
Each parameter provides important insights into the patient’s condition.
What parameters are monitored in the cardiovascular system?
- HR
- BP
- Cardiac Rhythm – ECG
- Pulse – quality + amplitude
- CO and venous pressure (CVP)
These parameters are critical for assessing tissue oxygen delivery and overall cardiovascular health.
How is heart rate (HR) significant in monitoring?
- Major determinant of CO
- Affects BP
- Influenced by species, size, and environment
CO is calculated as CO = HR x SV.
What does blood pressure (BP) measure?
Arterial hydrostatic pressure compared to atmospheric pressure
BP is affected by CO, peripheral resistance, arterial blood volume, and arterial compliance.
What is systemic vascular resistance determined by?
- Viscosity
- Vessel length
- Vessel radius
Afterload is the pressure the heart needs to exert to eject blood during contraction.
Define systolic arterial pressure (SAP).
Pressure in arteries during systole; highest pressure of cardiac cycle
Normal systolic pressures for dogs and cats are approximately 90-160 mmHg.
What is diastolic arterial pressure (DAP)?
Pressure in arteries when the heart is relaxed; lowest pressure of cardiac cycle
Normal diastolic pressures for dogs and cats are approximately 55-90 mmHg.
How is mean arterial pressure (MAP) approximated?
MAP = DAP + 1/3 (SAP-DAP)
MAP is crucial for assessing vital organ perfusion.
What is respiration?
Process of gas exchange
It involves both internal respiration (cellular) and external respiration (atmospheric).
What factors contribute to hypothermia during anaesthesia?
- Inhibition of thermoregulation
- Cold tables
- Clipped areas
- Open skin/abdomen
Anaesthetic drugs can inhibit vasodilation and shivering, leading to hypothermia.
What are the effects of severe hypothermia?
- Impaired cardiovascular function
- Bradycardia
- Hypoventilation
- Decreased metabolism
- Poor recovery
- Increased O2 demand
- Decreased immune function
- Coagulation / haemostatic abnormalities
Severe hypothermia is defined as a body temperature below 34°C.
What is the role of the central nervous system (CNS) in anaesthesia?
Anaesthesia depresses the CNS, affecting the level of consciousness
Monitoring changes in reflexes, muscle tone, respiration, and eye position is crucial.
What are the levels of monitoring during anaesthesia?
- Level 1: Manual and observational monitoring
- Level 2 and 3: Devices used (HR monitors, pulse ox, BP monitors, etc.)
Levels 2 and 3 employ various devices for continuous monitoring.
What is pulse oximetry?
Non-invasive method of measuring haemoglobin O2 saturation
It is considered the 5th vital sign and provides immediate monitoring of O2 saturation.
How does Doppler NIBP work?
Uses ultrasound waves to detect the frequency difference of moving blood cells
It provides an audible sound of blood flow based on the reflected signal.
What are the stages of anaesthesia?
- Stage 1: Awake
- Stage 2: Involuntary excitement
- Stage 3: Surgical anaesthesia (4 planes)
- Stage 4: Overdose
Each stage has distinct physiological and neurological characteristics.
What is the acceptable heart rate (HR) and respiratory rate (RR) for a patient under anaesthesia?
Varies by patient
Understanding these values is crucial for identifying complications.
What should be recorded during anaesthesia monitoring?
- Continuous monitoring
- Measurements every 5 minutes
- Document occurrences
- Legal documentation
This documentation is essential for clinical records and historical reference.
