Week 11 Flashcards
(34 cards)
Mr G is a 75-year-old man who has returned to the ward from the operating theatre following prostatectomy. On return, he has an epidural infusion for analgesia.
- Where is epidural analgesia inserted? (3 marks)
It is inserted into the space between the dura matter and the ligamentum flavum, at the spinal levels C7-T10
- What drugs are commonly used for epidural analgesia? (3 marks)
Lignocaine Prilocaine Mepivacaine Bupivacaine fentanyl
- What are common adverse effects of epidural analgesia? (3 marks)
Local complications at the site of injection- inflammation, haematoma, nerve injury, abscess formation, necrosis
Psychogenic reactions – hyperventilation, vasovagal syncope
Systemic effects of the vasoconstrictor – Sympathetic or central stimulation
Local effects of the vasoconstrictor – ischemia, necrosis, gangrene
Epidural – headache, hypotension, infections, nueropathies, paraesthesias and autonomic dysfunction
Allergies – rash, bronchospasm, anaphylaxis
Systemic effects – numbness of tongue, CNS stimulation
- What specific observations would you undertake while the epidural analgesia is in progress? (3 marks)
The epidural can affect sensory, motor and autonomic nerves, and observations should therefore include: date and time of observation; respiratory rate; oxygen saturations; pulse; urine output; itching; pain; sedation and nausea score; sensory level; motor block; blood pressure.
The epidural site should be checked daily for signs of infection, leakage or tenderness.
- Given the loss of sensation resulting from epidural analgesia, pressure area care must be rigorous, and micturation should be encouraged.
- What potential complications may arise from epidural analgesia? (3 marks)
Motor Loss - Gross motor weakness may be indicative of an epidural haematoma
Headache - Accidental dural puncture
Catheter misplaced into a vein - Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can cause seizures or cardiac arrest
Epidural abscess formation - Infection risk increases with the duration catheters are left in place
Bladder distention - The sensation of needing to urinate is often significantly diminished or even abolished after administration of epidural local anaesthetics
While a person is receiving a general anaesthetic, he or she must be continually monitored because:
a. The person has no pain sensation
b. Generalised CNS depression affects all body function
c. The person cannot move
d. The person cannot communicate
b. Generalised CNS depression affects all body function
Local anaesthetics are used to block feeling in specific body areas. If given in increasing concentrations, local anaesthetics can cause loss, in order, of the following:
a. Temperature sensation, touch sensation, proprioception and skeletal muscle tone
b. Touch sensation, skeletal muscle tone, temperature sensation and proprioception
c. Proprioception, skeletal muscle tone, touch sensation and temperature sensation
d. Skeletal muscle tone, touch sensation, temperature sensation and proprioception
a. Temperature sensation, touch sensation, proprioception and skeletal muscle tone
Proper administration of an ordered narcotic:
a. Can lead to addiction
b. Should be done promptly to prevent increased pain and the need for larger doses
c. Would include holding the drug as long as possible until the person really needs it
d. Should rely on the person’s request for medication
b. Should be done promptly to prevent increased pain and the need for larger doses
The benzodiazepines are the most frequently used anxiolytic drugs because:
a. They are anxiolytic at doses much lower than those needed for sedation or hypnosis
b. They can be stimulating
c. They are more likely to cause physical dependence than older anxiolytic drugs
d. They do not affect the neurotransmitters
a. They are anxiolytic at doses much lower than those needed for sedation or hypnosis
The nurse or midwife would expect administration of a NMJ blocker as the drug of choice to accomplish which of the following
a. Facilitate endotracheal intubation
b. Facilitate mechanical ventilation
c. Prevent injury during electroconvulsive therapy
d. Relieve pain during labour and birth
e. Treat myasthenia gravis
f. Treat a person with a history of malignant hyperthermia
a. Facilitate endotracheal intubation
b. Facilitate mechanical ventilation
c. Prevent injury during electroconvulsive therapy
Suxamethonium has a more rapid onset of action and a shorter duration of activity than the non-depolarising NMJ blockers because it:
a. Does not bind well to receptor sites
b. Rapidly crosses the blood-brain barrier and is lost
c. Is broken down by acetylcholinesterase that is found in the plasma
d. Is very unstable
c. Is broken down by acetylcholinesterase that is found in the plasma
- Describe the anatomical basis and function of the blood-brain barrier and its clinical implications for drug therapy.
Anatomy :the barrier is made of a layer of endothelial cells covered by a fatty sheath of glial cell joined by continuous tight intercellular junctions.
The blood-brain barrier clinical implications: allows only lipid soluble drugs (eg: anaesthetic and barbiturates)
While each medication used in General Anaesthesia (GA) has its own unique adverse reactions, describe those adverse reactions that are common to all Gas as they depress the cardiovascular and respiratory systems and reflexes.
Convulsions headache nausea and vomiting kidney or liver toxicity malignant hyperthermia hypersensitivity reactions
- What special precautions may need to be taken when administering either general or local anaesthetics to the following groups of patients;
Children
- upper airway obstruction risk
- careful monitoring due to immature systems and risk of adverse effects
- careful calculations
- more sensitive to non-depolarising muscle relaxant agents
- What special precautions may need to be taken when administering either general or local anaesthetics to the following groups of patients;
Elderly –
- decline in organ function,
- prolonged drug effects are seen in the elderly.
- drug drug interactions
- drug induced confusion
- What special precautions may need to be taken when administering either general or local anaesthetics to the following groups of patients;
Pregnancy and Childbirth –
- CNS-active drugs are lipid soluble, they are likely to cross the placenta and reach significant levels in the fetal blood stream.
- opioids can lead to respiratory depression in neonate
- What special precautions may need to be taken when administering either general or local anaesthetics to the following groups of patients;
Obesity –
- predisposition to hypertension, diabetes, respiratory system problems,
-the depth of anaesthesia and muscle relaxation may be a problem.
do not use highly fat soluble agents ie methoxyflurane
- What special precautions may need to be taken when administering either general or local anaesthetics to the following groups of patients;
Smoking -
- smokers are at risk of coronary heart disease, peripherial vascular disease and compromised lung function,
- postoperative complications are six times greater than non smokers patients.
- smoking increases patients sensitivity to muscle relaxants
- What special precautions may need to be taken when administering either general or local anaesthetics to the following groups of patients;
Alcohol intake -
- may have associated disease states - liver dysfunction, pancreatitis, gastritis and oesophageal varices
- anaethetic requirements may be increased because of the increase of liver drug metabolising enzymes present
- monitored for withdrawral symptoms
- Inhalation anaesthetics are gases or volatile liquids that can be administered by inhalation when mixed with oxygen. List the characteristics of inhalation anaesthetics.
Complete anaesthetics – can abolish superficial and deep reflexes
Provide controllable anaesthesia – depth of anaesthesia can be easily changed
Lung function is critical – route of administration and excretions is via the airways
Good anaesthetics but not usually analgesic properties – used with an adjunct analgesic
Rapid recovery – excreted in expired air
Allergic reactions uncommon
- The alternative to inhaled anaesthetics is the use of intravenous anaesthetics to induce and maintain general anaesthesia. In the table below list the advantages of intravenous anaesthesia
Advantages rapidly unconsciousness are readily controllable Have amnesic effects Reduce the amount of inhalation agents required Allow prompt recovery with minimal doses Are simple to administer and have pleasant induction Do not pose hazard or fire or explosion.
- The alternative to inhaled anaesthetics is the use of intravenous anaesthetics to induce and maintain general anaesthesia. In the table below list the disadvantages of intravenous anaesthesia
Disadvantages
Have minimal muscle relaxation and analgesic effect.
Are subject to renal metabolism and renal excretion
Commonly cause hypertension reaction(to drug or vehicle)
Cause tissues irritation if drug or vehicle infiltrates tissues or if arterial injections occur.
Cause hypotension, laryngospasm and respiratory failure after overdosage or prolong administration.
- Local anaesthesia (LA) refers to the direct administration of an agent to tissues to induce the absence of pain sensation in that part of the body. There are multiple techniques by which Las can be administered. Briefly discuss the key uses of each method;
Topical or Surface Anaesthesia – are used to relieve pain and itching caused by conditions such as sunburn or other minor burns, insect bites or stings, poison ivy, poison oak, poison sumac, and minor cuts and scratches.
Infiltration Anaesthesia – it is produced by injecting dilute solutions (0,1%) of the agent into the skin and then subcutaneously into the region to be anaesthetised. skin carcinoma removals, plastic surgery
Nerve Block Anaesthesia – The LA is injected into the vicinity of a nerve trunk and inhibits the conduction of impulses to and from the area supplied by the nerve.
• Peripheral nerve block – motor and sensory block
• Used for foot/hand surgery
Epidural (Extradural) Anaesthesia – is an injection of LA into the epidural space, which is situated between the dura matter and the ligamnetum flavum at spinal cord level C7-T10. Used in cesarean sections or in labour
Spinal (subarachnoid) Anaesthesia -
LA injected into the CSF into the subarachnoid space, below the level of termination of the spinal cord. (L3-4 or L4-5)
• Effects lower part of spinal cord and nerve roots
• Allows for surgery without general anaesthetic
lower limb surgeries on older patients or those at risk of GA
Describe the mechanism of action of the two types of neuromuscular blocking drugs.
non-depolarising neuromuscular blockers -
hey act by competitively blocking the binding of ACh to its receptors, and in some cases, they also directly block the ionotropic activity of the ACh receptors.
Depolarising neuromuscular blockers
These agents act by depolarizing the plasma membrane of the skeletal muscle fiber. This persistent depolarization makes the muscle fiber resistant to further stimulation by ACh.
