Anaesthetics Flashcards
What are the two types of anaesthesia?
General anaesthesia – making the patient unconscious
Regional anaesthesia – blocking feeling to an isolated area of the body (e.g., a limb)
What is malignant hyperthermia?
A severe reaction to certain drugs used for anesthesia.
Symptoms -
Increased body temperature (hyperthermia)
Increased carbon dioxide production
Tachycardia
Muscle rigidity
Acidosis
Hyperkalaemia
What is the treatment of malignant hyperthermia?
Dantrolene
What is the triad of general anesthesia and give examples?
Analgesia - Fentanyl
Muscle Relaxants - Rocuronium bromide, Suxamethonium chloride
Hypnosis - Ketamine, Propofol
In an emergency scenario, where detailed pre-planning is not possible, which procedure is used to gain quick and safe control over the airway via intubation?
Rapid Sequence induction
It is also used in non-emergency situations where the airway needs to be secured quickly to avoid aspiration, such as in patients with gastro-oesophageal reflux or pregnancy.
Which common condition can lead to gastrointestinal bleeding in critically unwell patients in ICU?
Stress related mucosal disease
What do inotropes do?
Increase cardiac contractility
What do vasopressors do?
Increase vasoconstriction
What is the APACHE score used for?
To predict mortality at the time of admission to ITU
What is FiO2?
The fraction of inspired O2
This means the concentration of oxygen in the gas that is being inhaled
Where is the anaesthetic agent injected to achieve spinal anaesthesia?
Into the cerebrospinal fluid in the subarachnoid space
Which other term can be used to describe a spinal anaesthesia / spinal block?
Central neuraxial anaesthesia
What type of catheter is a Swan-Ganz catheter?
Pulmonary Artery Catheter
Inserted into the pulmonary artery used to measure pressure in the right atrium
Which inhaled medication is most commonly used to maintain general anaesthesia?
Sevoflurane
Where are the most common sites for insertion of a central venous catheter?
Internal Jugular Vein
Subclavian Vein
Femoral Vein
What are the two main methods for reducing the risk of venous thromboembolism (VTE) in critically unwell patients?
LMWH ( Enoxaparin )
Intermittent Pneumatic Compression devices
Which intravenous medication is most commonly used to induce general anaesthesia?
Propofol
What adverse effect can epidural anaesthesia have on labour and delivery?
Increased second stage ( Second stage describes the period of time from when the cervix is fully dilated to when the baby is born )
Increased likelihood of instrumental delivery ( Forceps / Ventouse )
Which term refers to the amount that the heart muscle is stretched when filled with blood just before a contraction?
Preload
Where is the anaesthetic agent injected to achieve epidural anaesthesia?
Into the epidural space , layer before dura mater
Which term describes anaesthetic agents that are liquid at room temperature and need to be vaporised into a gas to be inhaled? (1)
What device is used for this purpose? (1)
Volatile
Vaporiser
Which medication is used to reverse the effects of opioids in life-threatening overdose?
Naloxone
What does the term cardiac output refer to?
What is the formula for cardiac output?
The volume of blood pumped out by the heart per minute
CO = SV x HR
Which class of drug is typically used as premedication to relax the muscles and reduce anxiety before a general anaesthetic?
Give an example of this class of drug?
Benzodiazepines
Midazolam , Lorazepam
What methods/masks can be used to deliver different concentrations of oxygen without adding or controlling the pressure?
Nasal cannula
Simple face mask
Venturi mask
Non-rebreather mask
What is the Fio2 and maximum flow rate of a nasal cannula?
24 – 30% O2 (maximum flow rate of 4L/min)
Nasal cannulae (NC) are used for mild hypoxia, typically in non-acute situations.
What is the Fio2 and flow rate of a Simple face mask?
The mask delivers 30 – 40% O2 (flow rate 5-10 L/min)
Simple face masks (also called Hudson masks) are typically used to treat mild to moderate hypoxia.
What is the Fio2 and flow rate of a Non-rebreather mask?
This mask delivers approximately 70% O2 when used with a 15L oxygen flow rate.
Used for significant hypoxia. Non-rebreather masks can deliver high FiO2 concentrations as the oxygen is inhaled from both the reservoir bag as well as the direct oxygen source.
How do you fit a non-rebreather mask?
For the mask to work effectively, the reservoir bag needs to be filled before the mask is fitted to the patient. To fill the reservoir bag, obstruct the valve with your finger until the bag is filled with oxygen.
What are Venturi masks used for?
Venturi masks are designed to deliver constant FiO2 regardless of the patient’s respiratory rate and flow pattern (i.e. a fixed-performance device).
They are used to deliver oxygen to patients with chronic obstructive pulmonary disease (COPD) due to the risk of type 2 respiratory failure.
The green venturi mask MUST be on a flow rate of 12-15L to work
Which term describes the situation where pain is experienced with sensory inputs that do not normally cause pain (e.g., light touch)?
Allodynia
What is the first-line medication for managing trigeminal neuralgia?
Carbamazepine
Which term refers to the resistance that the heart must overcome to eject blood from the left ventricle, through the aortic valve and into the aorta?
Afterload
What are the two groups of nerve fibres that transmit pain? (2)
Which of these is myelinated? (1)
Which has a larger diameter? (1)
C Fibres and A-delta fibres
A-fibres and myelinated and have a larger diameter
Which term refers to pain and restriction when opening the jaw?
Trismus
What is the most extreme form of respiratory support, where respiratory failure is not adequately managed by intubation and ventilation?
Extracorporeal Membrane Oxgenation
How is the size of an oropharyngeal (Guedel) airway measured to ensure the correct size for the patient?
From the centre of the mouth to the angle of the jaw
An oropharyngeal airway (also known as an oral airway, OPA or Guedel pattern airway) is a medical device called an airway adjunct used in airway management to maintain or open a patient’s airway. It does this by preventing the tongue from covering the epiglottis, which could prevent the person from breathing.
Which term refers to the resistance in the systemic circulation that the heart must overcome to pump blood around the body?
Systemic Vascular Resistance
What are the two categories of muscle relaxants that may be used during a general anaesthetic? (2)
Give examples of each. (2)
Depolarising - Suxamethonium Chloride
Non-depolarising - Rocuronium Bromide
What is the method of action of Ondansetron?
Which kind of patients should it be avoided in?
5HT3 Receptor Antagonist
Those at risk of a prolonged QT Interval
What type of line is inserted into a peripheral vein and fed through the venous system until the tip is in a central vein (the vena cava)?
Peripherally Inserted Venous Catheter ( PICC Line)
What is the difference between CPAP and non-invasive ventilation (or BiPAP)?
CPAP provides continuous positive pressure through the mask and into the airway, which helps to keep the airway open -> Type 1 Respiratory Failure
BiPAP/NIV provides both high and low pressure to aid inhalation and exhalation ( Ventilation ) -> Type 2 Respiratory Failure
What is the name of the extra hole on the side of the tip of an endotracheal tube that gas can flow through should the main opening become occluded?
Murphy’s Eye
How is the size of a nasopharyngeal airway measured to ensure the correct size for the patient?
From the nostril to the tragus of the ear
When would you use a nasopharyngeal airway instead of a oropharyngeal airway?
In a deeply unresponsive/unconscious patient, an oropharyngeal airway is safe to use because the gag reflex will be depressed. Another advantage of the nasopharyngeal airway is that it can be used in patients with mouth trauma, where an oropharyngeal airway cannot or should not be used.
Give an example of an alpha-2-adrenergic agonist that may be used as premedication before a general anaesthetic to reduce pain?
Clonidine
What is sugammadex used for?
To reverse the effects of nondepolarizing muscle relaxants e.g Rocuronium
How long should patients not have clear fluids before surgery?
2 hours of no clear fluids (fully “nil by mouth”)
Why must patients be NBM during the surgery?
The purpose of fasting is to make sure they have an empty stomach, to reduce the risk of the stomach contents refluxing into the oropharynx (throat), then being aspirated into the trachea (airway). Gastric contents in the lungs creates an aggressive inflammatory response, causing pneumonitis (inflammation of the lung tissue).
It protects the airway
What are the types of airways ?
Laryngeal Mask ( LMA )
Nasopharyngeal airway
Orophayngeal airway
Endotracheal intubation (ETA) - Protection against aspiration and gastric insufflation. More effective ventilation and oxygenation. Facilitation of suctioning.