Week 11

Question 1

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.

1. Where is epidural analgesia inserted? (3 marks)

Answer 1

It is inserted into the space between the dura matter and the ligamentum flavum, at the spinal levels C7-T10

Question 2

2. What drugs are commonly used for epidural analgesia? (3 marks)

Answer 2

Lignocaine
Prilocaine
Mepivacaine
Bupivacaine
fentanyl

Question 3

3. What are common adverse effects of epidural analgesia? (3 marks)

Answer 3

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

Question 4

4. What specific observations would you undertake while the epidural analgesia is in progress? (3 marks)

Answer 4

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.

Question 5

5. What potential complications may arise from epidural analgesia? (3 marks)

Answer 5

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

Question 6

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

Answer 6

b. Generalised CNS depression affects all body function

Question 7

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

Answer 7

a. Temperature sensation, touch sensation, proprioception and skeletal muscle tone

Question 8

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

Answer 8

b. Should be done promptly to prevent increased pain and the need for larger doses

Question 9

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

Answer 9

a. They are anxiolytic at doses much lower than those needed for sedation or hypnosis

Question 10

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

Answer 10

a. Facilitate endotracheal intubation
b. Facilitate mechanical ventilation
c. Prevent injury during electroconvulsive therapy

Question 11

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

Answer 11

c. Is broken down by acetylcholinesterase that is found in the plasma

Question 12

1. Describe the anatomical basis and function of the blood-brain barrier and its clinical implications for drug therapy.

Answer 12

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)

Question 13

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.

Answer 13

Convulsions
headache
nausea and vomiting
kidney or liver toxicity
malignant hyperthermia
hypersensitivity reactions

Question 14

3. What special precautions may need to be taken when administering either general or local anaesthetics to the following groups of patients;

Children

Answer 14

• 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

Question 15

3. What special precautions may need to be taken when administering either general or local anaesthetics to the following groups of patients;

Elderly –

Answer 15

• decline in organ function,
• prolonged drug effects are seen in the elderly.
• drug drug interactions
• drug induced confusion

Question 16

3. What special precautions may need to be taken when administering either general or local anaesthetics to the following groups of patients;

Pregnancy and Childbirth –

Answer 16

• 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

Question 17

3. What special precautions may need to be taken when administering either general or local anaesthetics to the following groups of patients;

Obesity –

Answer 17

• 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

Question 18

3. What special precautions may need to be taken when administering either general or local anaesthetics to the following groups of patients;

Smoking -

Answer 18

• 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

Question 19

3. What special precautions may need to be taken when administering either general or local anaesthetics to the following groups of patients;

Alcohol intake -

Answer 19

• 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

Question 20

4. Inhalation anaesthetics are gases or volatile liquids that can be administered by inhalation when mixed with oxygen. List the characteristics of inhalation anaesthetics.

Answer 20

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

Question 21

5. 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

Answer 21

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.

Question 22

5. 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

Answer 22

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.

Question 23

6. 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;

Answer 23

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

Question 24

Describe the mechanism of action of the two types of neuromuscular blocking drugs.

Answer 24

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.

Question 25

7. Medication may be administered to the eye using a variety of formulations. Explain the difference between eye-drops, eye ointments or gels and eye-lotions and appropriate uses for each.
8. • Eye drop:

Answer 25

• Formulated in aqueous or oily solution.
• Quick absorption and effect – brief duration of action.
• Systemic effects are possible after absorption without the drug having passed through the liver.
• Oily drops are less common as they may interfere with vision but provide longer retention time on cornea and more stable than aqueous drops.
infections and dry eye

Question 26

7. Medication may be administered to the eye using a variety of formulations. Explain the difference between eye-drops, eye ointments or gels and eye-lotions and appropriate uses for each. #
8. • Eye ointment:

Answer 26

• Semisolid preparations intended for topical application to the skin or mucous membrane.
• More stable than aqueous solutions
• Less absorption of the drug into the lacrimal ducts.
• They are safer for home use with potent drugs
• Allows for longer retention time on conjunctival surface.
use for antiviral drugs when treating shingles

Question 27

7. Medication may be administered to the eye using a variety of formulations. Explain the difference between eye-drops, eye ointments or gels and eye-lotions and appropriate uses for each.

Eye lotion:

Answer 27

• Irrigating solutions are used to wash foreign materials from the eyes.
• Sterile
• Used if eyes splashed with lime
also used during intraocular surgery

Question 28

. Discuss the mechanism of action and indications for the following optic medication. Give an example of a commonly used agent from each class.
Mydriatics –

Answer 28

are drugs that causes pupil dilation (mydriasis). Used to facilitate examination of the peripheral lens and retina in the diagnosis of ophtamolic disorder. Eg: ATROPINE

Question 29

. Discuss the mechanism of action and indications for the following optic medication. Give an example of a commonly used agent from each class.
Anticholinergics –

Answer 29

agents reversibly block ACHm receptors on iris sphincter muscle and ciliary muscle, producing mydriasis and cyclopegia, ( paralysis of cilliary muscle).eg: ATROPINE
They are indicated to relieve ocular pain by relaxing inflamed intraocular muscle in inflammations. Such as uveitis and cheratitis.

Question 30

. Discuss the mechanism of action and indications for the following optic medication. Give an example of a commonly used agent from each class.

Sympathomimetics –

Answer 30

mimic or potentiate alpha receptor-mediated action of noradrenaline on the dilator muscle of the iris resulting in mydrasis, vasoconstriction and decreased congestion of conjuctival blood vessels . Used to treat wide angle glaucoma. PHENYLEPHRINE

Question 31

. Discuss the mechanism of action and indications for the following optic medication. Give an example of a commonly used agent from each class.

Cycloplegics agents –

Answer 31

drugs that paralyse cilliary muscle causing loss of accommodation, invariably accompanied by mydrasis. ATROPINE used
• To prevent accommodation during refraction
• Pain relief in iridocyclitis
• Induce chemical occlusion for treatment for amblyopia

Question 32

. Discuss the mechanism of action and indications for the following optic medication. Give an example of a commonly used agent from each class.

Miotic agents –

Answer 32

Are drugs that constrict the pupil – cause miosis. The clinical uses are to treat glaucoma and also have been used to reverse mydriatic effects. Likely to cause blurring of vision and spasm of accommodation. PILOCARPINE

Question 33

. Discuss the mechanism of action and indications for the following optic medication. Give an example of a commonly used agent from each class.

Muscarinic agonists –

Answer 33

stimulate muscarinic receptors in the circular muscle of the iris, causing contraction and thus pupil constriction. It is used for rapid miosis (contriction of the pupil) during surgery PILOCARPINE

Question 34

. Discuss the mechanism of action and indications for the following optic medication. Give an example of a commonly used agent from each class.

Ocular decongestants :

Answer 34

Vasoconstrictors, decongestant effects in the eye, they reduce hyperaemia and fluid exudation, therefore they reduce reddening and sign of inflammation. PHENYLEPHRINE