Complications in Anaesthesia Flashcards
List of minor complications in anaesthesia?
- Airway injuries
- Eye injuries: corneal ulceration if eyes not taped closed
- Positional injuries: nerve damage over bony prominences
- Regional anaesthesia complications: epidural abscess, meningitis, epidural haematomoa, nerve injuries, post-spinal headache
- Central venous cannulation complications
- PONV
- Awareness
- Mild Hypothermia
What are the complications of central venous cannulation?
Early:
Technical: pnuemothorax, haemothorax, nerve damage
Dysrhythmias from guide wire
Air embolism
Late:
Infection: sepsis or endocarditis
Thrombosis
Tamponade
What factors need to be considered for PONV?
- Patient factors: children, females, non-smoker, hx motion sickness, previous PONV, obesity
- Anaesthetic factors: prolonged pre-op starvation, hypotension (epidurals, spinals), emetic drugs (opiates, etomidate, ketamine, N20, volatiles)
- Surgical factors: eye and ear surgery, intra-abdominal surgery
- Post-op factors: pain, opiates, hypotension, forcing oral fluids too soon post-op
Prevention of PONV?
Avoid emetic drugs
Regional anaesthesia is an option
TIVA with propofol (intrinsic anti-emetic properties)
Administration of anti-emetic drugs in theatre for high risk PONV patients
Keep patient well hydrated with IV fluids
Anti-emetic drug examples?
Droperidol
Prochlorperazine
Ondansetron
Dexamethasone/betamethasone
List the major/life-threatening complications in anesthesia?
- Endotrachial intubation failure
- Aspiration
- Respiratory complications (laryngospasms, bronchospasm, obstruction, post-op respiratory depression, pneumothorax)
- Cardiovascular complications (hypotension, hypertension, dysrhythmias, cardiac arrest, MI)
- Equipment failure
- Anaphylaxis
- Pharmacogenetic diseases (malignant hyperthermia, halothane hepatitis, scoline apnoea, porphyria)
Clinical presentation of anaphylaxis?
Triad of skin reactions, respiratory and cardiac effects
Skin = wheal and flare, urticaria
Resp = angio-oedema, bronchospasm, hypoxia
CVS = hypotension, tachycardia, cardiovascular collapse
What drugs are most likely to cause anaphylaxis in anaesthesia?
Antibiotics
Muscle relaxants
Definition of malignant hyperthermia?
A rare inherited syndrome
Characterised by life-threatening acute hypermetabolic state
Triggered by exposure to a triggering agent
What are the triggering agents for malignant hyperthermia in anaesthesia?
All volatile vapours
Suxamethonium
Pathophysiology of MH?
Caused by a defect in a receptor in the sarcoplasmic reticulum
Ryanodine receptor - a calcium channel receptor
Oce the receptor is exposed to the trigger agent, the receptor stays open and floods the cell with calcium
Resultant persistant contractile state
Hyperthermia >38, is a late stage of MH
Clinical features of MH?
Tachycardia Tachypnoea (if breathing spontaneously) Increased O2 consumption Eventually cyanosis Hypercapnia Masseter muscle spasm Whole body skeletal muscle rigidity Dysrhymias Cardiovascular collapse Metabolic and respiratory acidosis Hyperkalaemia Hyperthermia Myoglobinuria Untreated, will progress to ARF, heptic failure, coagulopathy, cerebral oedema and death
Management protocol for MH?
Discontinue triggering agent
Call for help
Hyperventilate with 100% 02 at high flows
Mix DANTROLENE SODIUM with sterile water, administer 2,5 mg/kg IV ASAP
Institute cooling measures
Treat associated complications (i.e. dysrhythmia)
Administer additional dantrolene doses as needed
Transfer to ICU
MH-safe anaesthesia?
Avoid GA if possible and use regional technique
If GA needed: Patient should be first on the list Use machine with no vapourisers on it Machine should be flushed with high flow O2 for 20 minutes prior to use Propofol TIVA technique Non-deopolarising muscle relaxants Know location of dantrolene
Risk factors for Halothane hepatits?
Repeat exposure to halothane within 6 months Middle age Females Obesity Existing hepatic disease
