Managing complications of anaesthesia Flashcards
What are the most common complications during anaesthesia?
- Insufficient depth
- Hypotension
- Hypertension
- Bradycardia
- Tachycardia
- Apnoea
- Hypoxaemia
- Hypothermia
- Bad or prolonged recovery
What are some troubleshooting steps for insufficient depth of anaesthesia?
- Vaporiser setting too low
- Leaking of anaesthetic agent
- Increased cardiac output
- Premedication wearing off
What should be done if a patient is connected to a rebreathing circuit and insufficient depth is observed?
Inject a small dose of induction agent and turn up the vaporizer and fresh gas flow.
How is insufficient depth o anaesthesia managed when the patient is on a non rebreathing circuit
Turn the vaporiser up and if the respiratory rate as increased, also turn up the FGF
What are the main causes of hypotension during anaesthesia?
- Vasodilation
- Hypovolaemia or bleeding
- Decreased cardiac contractility
- Cardiac arrhythmias
- Bradycardia
What are cause and signs signs of vasodilation related hypotension?
- Drugs (inhalant, propofol, acepromazine)
- Histamine release
- Sepsis
- Red mucous membrane
- CRF <= 1
- Low blood pressure
What is the treatment for vasodilation-induced hypotension?
- Start surgery
- Decrease inhalant concentration
- Administer fluids (2-5 ml/kg/h)
- +/- Vasopressors
What is the total blood volume for dogs and cats?
- Dog: 80-90 ml/kg
- Cat: 60-70 ml/kg
When and what treatment is commonly administered for bloodloss during surgery
Crystalloids for <10% loss
Colloids for ~20% loss
Blood transfusion for >20% loss
What are key points to remember about how intraoperative haemorrhage effects the patient
Anaesthesia can blunt tachycardia
Immediate haematocrit may not reflect true blood loss
Anaesthetic requirements decrease
Cardiac/anemic patients tolerate blood loss poorly
What can cause decreased cardiac contractility during anaesthesia
cardiac disease
Anaesthetic drugs (inhalants, alpha2 agonists, propofol, alfaxalone)
How is reduced cardiac contractiliy during anaesthesia managed
Decrease anaesthetic depth
Inotropes (dobutamine, dopamine)
Fluids + inotropes if hypovolaemia present
What are possible causes of hypertension during anaesthesia?
- Light anaesthesia
- Pain
- Hypoxaemia
- Hypercapnia
- Metabolic acidosis
- Cardiovascular disease
- Severe hypoglycaemia
How might hypertension under anaesthesia be managed
Treat underlying cause
Increase vaporizer setting
Beta blockers
Acepromazine
What are the possible causes of bradycardia during anaesthesia?
- Vagal stimulation
- Hypothermia
- Deep anaesthesia
- Hypertension
- Hyperkalemia
- Severe hypoxia
- Severe hypoglycaemia
- Severe acidosis
- Drugs (methadone, fentanyl)
What is the treatment for bradycardia?
Depends on the cause; necessary if cardiac output is compromised or arrhythmias are present.
ie glycopyrolate or atropine if you this its causing hypotension
What are possible causes of tachycardia during anaesthesia?
- Light anaesthesia
- Pain
- Hypercapnia
- Hypoxia
- Hypotension
- Hyperthermia
- Hypokalemia
- Hypoglycaemia
- Drugs (terbutaline)
What can cause apnoea during anaesthesia?
- Drugs
- Hypocapnia
- Pain
- Deep anaesthesia
- Cardiac arrest
What is the definition of hypoxia?
SPO2 < 90% = PaO2 < 60 mmHg.
What are causes of hypoxia in an anaethetised patient
- Mechanical obstruction
- Fault in oxygen delivery
- Cardiac failure
- Respiratory failure
How can hypothermia occur during anaesthesia?
CNS depression (thermoregulatory center)
Vasodilation
Heat loss by conduction, convection, evaporation, radiation eg cold table, fluids scrubs etc
Exposure to cold gases and open surgical fields
What are the consequences of hypothermia during anaesthesia?
- Decreased metabolism
- Prolonged recovery
- Decreased heart rate, respiratory rate, and blood pressure
- Anaesthetic overdose
- Acidosis and electrolyte imbalance
- Arrhythmias and coagulation problems below 30°C
- Possible death from respiratory and/or cardiac arrest
What are the methods to prevent hypothermia during anaesthesia?
- Keep warm from the beginning
- Minimize time between induction and procedure
- Use heat pads, infrared lamps, electric blankets
- Use rebreathing systems
- Lowest fresh gas flows possible
- Use HME devices
- Cover extremities with bubble wrap
- Use warm saline at the end of laparotomy
- Decrease dose of acepromazine in susceptible animals
What should be monitored throughout procedures lasting longer than 20 minutes?
Temperature.
