Anaesthetics Flashcards
What is pre oxygenation?
Patients breathe 100% oxygen for several minutes to give them a reserve of oxygen for intubation
What premedication is given?
Benzodiazepines to relax muscles, reduce anxiety and cause amnesia
Opiates to reduce pain and reduce the hypertensive response to the laryngoscope
Alpha-2-adrenergic agonists (e.g. clonidine) to help with sedation and pain
What is RSI?
Rapid sequence induction/intubation
What is the triad of general anaesthesia?
Hypnosis
Muscle relaxation
Analgesia
What are examples of intravenous hypnotic agents?
Propofol
Ketamine
Thiopental sodium
Etomidate
What are examples of inhaled hypnotic agents?
Sevoflurane
Desflurane
Isoflurane
Nitrous oxide
What does volatile agents mean?
They are liquid at room temp and so need to be vaporised into a gas to be inhaled
Sevoflurane, desflurane and isoflurane are examples
What are the two categories of muscle relaxants?
Depolarising (e.g. suxamethonium)
Non-depolarising (e.g. rocuronium and atracurium)
What can reverse the effects of the neuromuscular blocking medications?
Cholinesterase inhibitors (e.g. neostigmine)
Sugammadex - specifically to reverse non-depolarising muscle relaxants
What opiates are commonly used in anaesthetics?
Fentanyl
Alfentanil
Remifentanil
Morphine
When are antiemetics given?
At the end of the procedure to prevent post-op nausea and vomiting
What are common antiemetics given?
Ondansetron - avoid in long QT
Dexamethasone - caution in diabetic or immnocompromised
Cyclizine - caution with heart failure or elderly
What needs to happen in emergence?
Muscle relaxant needs to have worn off before patient regains consciousness
Use nerve stimulator to test - train of four stimulation - needs to remain strong response for all four otherwise it has not fully worn off
Can use medication to reverse effects
What is malignant hyperthermia
Rare but potentially fatal hyper metabolic response to anaesthesia
Risk is mainly with volatile anaesthetics and suxamethonium
Often genetic, in an autosomal dominant pattern
What are the features of malignant hyperthermia
Increased body temp
Increased CO2 production
Tachycardia
Muscle rigidity
Acidosis
Hyperkalaemia
What is malignant hyperthermia treated with?
Dantrolene - interferes with the movement of calcium ions
What is an arterial line used for?
Accurately monitoring blood pressure and for ABG monitoring
NEVER for medication
When are central lines used?
Giving medications that are too irritating for peripheral cannula: e.g. inotropes, amiodarone, fluids with a high potassium concentration
Taking blood samples
What is a PICC line?
Peripherally inserted central catheter
Low risk of infection
What is a Hickman line?
Tunnelled central venous catheter
Enters the skin on the chest, through the subcutaneous tissue into the subclavian or jugular vein
Cuff that surrounds the Cather near skin insertion, promoting adhesion.
More permanent and reduced risk of infection
What are pulmonary artery catheters used for?
Specialist cardia centres for close monitoring of cardiac function and response to treatment
To measure pulmonary artery pressure
What is a Portacath?
Small camber under the skin used to access the device.
Most long term
What are the key side effects of NSAIDs?
Gastritis with dyspepsia
Stomach ulcers
Exacerbation of asthma
Hypertension
Renal impairment
CVS disease
Opioids for breakthrough pain should be what fraction of background dose?
1/6
Why is nutritional support so important for patients in ICU?
Their bodies are in hyper metabolic states, at high risk of malnutrition
Why does TPN have to be given through a central line rather than peripherally?
It is very irritant to veins and can cause thrombophlebitis
What are some complications of intensive care?
Ventilator can cause lung injury or pneumonia
Catheter can cause UTI
Central venous catheters can cause bloodstream infections
Stress-related mucosal disease (erosion of the upper GI tract)
Delirium
VTE
Critical illness myopathy
Critical illness neuropathy
What is something that reduces risk of ventilator induced pneumonia?
Elevation of bed to 30 degrees
Reduces risk of aspiration of secretions from stomach
Regular mouth care
What is a way to reduce risk of venous catheter related bloodstream infections?
Antibiotic impregnated or silver impregnated catheters
What is the pathophysiology of stress-related mucosal disease?
Impaired blood flow
Can be prevented by NG feeding early just to keep stomach active
What is a medication used in ICU to sedate agitated patients?
Dexmedetomidine
What is an important cause of critical illness myopathy?
Corticosteroids or muscle relaxants
What is key in reducing the risk of critical illness polyneuropathy?
Good glycemic control
What does raised bicarbonate on an ABG indicate?
That the patient chronically retains CO2
Apart from an anxiety attack, what is the other common cause of respiratory alkalosis?
PE
What causes metabolic alkalosis?
Loss of hydrogen ions
GI vomiting
Kidneys - usually due to increased activity of aldosterone (e.g. Conn’s, liver cirrhosis, heart failure loop diuretics, thiazide diuretics)
