10. Which of the following should be avoided for pain control in malignant conditions?
A
RemifentanilB
FentanylC
PethidineD
CodeineE
Methadone.11. Which of the following is not an alternative strategy for the treatment of chronic pain?
A
TamoxifenB
RadiotherapyC
CorticosteroidsD
AntidepressantsE
Tramadol.Answers: Multiple choice questions
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The anaesthetic triad
1. C
The anaesthetic triad consists of unconsciousness, pain relief and muscle relaxation in varying degrees for all procedures. Amnesia may occur but it is not actually sought. It is an interesting debating point as to whether it would be reasonable to offer amnesia without the other components since some may believe that it does not matter what the patient experiences as long as they do not remember it.
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Laryngeal mask airway
2. B
An unprotected airway with risk of aspiration is the main problem of the LMA over an
endotracheal tube. Unreliable placement and tube obstruction should be no different if both are used correctly.
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Correct placement of an endotracheal tube
3. D
Unrecognised incorrect placement of an endotracheal tube can have disastrous consequences, and often a failure to accept the possibility that the tube is not in the trachea is a cause of delay. It has now become a standard within Western practice to verify correct tube placement by seeing a trace on the capnograph – carbon dioxide monitor. Unfortunately, being able to hear breath sounds,
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seeing the chest moving and actually visualizing the tube going through the vocal cords with a Mackintosh laryngoscope are not sufficiently reliable.
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Suxamethonium (succinylcholine)
4. E
Suxamethonium is a short-acting muscle relaxant of the depolarising class. Its use is associated with muscle fasciculations shortly before relaxation occurs. Muscle tone returns after 3–4 min in most cases. Suxamethonium is metabolised by pseudocholinesterase and its effect is prolonged in those with an inherited or acquired deficiency in this enzyme. Examples of acquired deficiency include pregnancy and liver diseases. Patients would not complain of being paralysed for a long time because it would be necessary to keep them anaesthetised until normal muscle power has returned. Diplopia can occur with any muscle relaxant because of the sensitivity of the orbital muscles of the eye. Patients who have had suxamethonium are unlikely to complain of diplopia, however, because they will still be anaesthetised when the effect of suxamethonium has worn off.
Suxamethonium is a known trigger for malignant hyperpyrexia which can be associated with an increase in body temperature, but again the patient would not complain of this. Interestingly, other drugs used during anaesthesia can also increase body temperature, most importantly atropine. A surprisingly large number of patients do complain of generalized muscle aches and pains, usually in the postural muscles and most often in young and fit males. This is thought to be related to the muscle fasciculations.
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Lidocaine vs bupivacaine
5. E
Lidocaine and bupivacaine are both local anaesthetics used for local infiltration, field blocks and spinal and epidural blocks. Bupivacaine should not be used for IV regional anaesthesia (Bier’s block). Bupivacaine is considerably more cardiotoxic than other local anaesthetics.
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Bier’s block
6. A
Although other local anaesthetics can be used for Bier’s block, prilocaine is advocated as the safest and best agent to use. As stated above, bupivacaine should not be used.
7. E
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Assessment of pain
8. B
Although all the other answers are features of inadequate pain relief, they are subjective measures. The best way of assessing the adequacy of pain relief is to ask the patient about the quality of pain relief, or, more formally, to ask them to complete an analogue score where a mark is placed on a 10 cm line, with ‘no pain’ at one end and ‘the worst pain ever’ at the other.
9. C
Too much pain relief, usually associated with opioid use, will result in hypercarbia, slow respiratory rate, often with large tidal volumes, and a depression of conscious level.
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Chronic pain control
10. A
Remifentanil is an ultra-short-acting opioid which is often used as part of a total intravenous anaesthetic (TIVA) regimen. It is very short-acting and is not used in chronic pain circles. Any of the other agents could be used and are often used in varying preparations – skin patches, oral as a syrup, subcutaneous or intravenous.
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14: ANAES TH ESIA AN D P AI N R E LI E F 121 11. E
Many agents other than well known analgesics are used as adjunctive therapy in patients with chronic pain – particularly when related to cancer. Tramadol is an agent on the second rung of the WHO pain ladder – it is an intermediate-strength opioid and, as such, would have been tried before adjunctive therapy.
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122
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Diathermy
1. Which of the following statements with regard to diathermy are false?