British Journal of Anaesthesia | CEPD Reviews | Volume 1 Number 6 2001. 191.
99. Concerning intra-ocular pressure (IOP): (a) True; (b) False; (c) False; ...
Multiple choice questions and answers
Multiple Choice Answers radiograph, electrolytes, and a pacemaker check by cardiac technicians. Other tests should only be ordered if there are additional clinical reasons.
99. Concerning intra-ocular pressure (IOP): (a) True; (b) False; (c) False; (d) True; (e) True (c) Normal IOP is 16 ± 5 mmHg. (d,e) IOP is determined by the equilibrium of production and drainage of aqueous humour, intraocular blood volume (which can be affected by central venous pressure) and scleral capacity and rigidity.
105. Rate modulation:
100. The following drugs normally cause a decrease in IOP: (a) True; (b) False; (c) False; (d) True; (e) False (b) Metoclopramide, given i.v., causes a transient increase in IOP of about 30 min. (c) Ketamine causes a rise in IOP by an increase in systemic blood pressure, choroidal blood volume and possibly contraction of extra-ocular muscles. (e) Midazolam administered i.v. pre-induction has no effect on intra-ocular pressure. 101. The following reliably obtund the rise in IOP caused by succinylcholine and endotracheal intubation: (a) True; (b) False; (c) True; (d) False; (e) False (a,c) Both alfentanil and remifentanil obtund the rise in IOP accompanying the use of succinylcholine. (b) Fentanyl should be used at a dose of 5 µg kg–1 to have similar effects. (e) Pretreatment with non-depolarising agents prior to administration of succinylcholine will not reliably obtund the rise in IOP, possibly because succinylcholine has been shown to cause a rise in IOP even with extra-ocular muscles detached from the globe. 102. Concerning topically administered ocular drugs: (a) False; (b) True; (c) False; (d) True; (e) True (a) Adverse systemic effects are more common in children because a toxic blood concentration may be reached more easily. Infants less than 4 months of age have a reduced hepatic metabolism. (c) Applying finger pressure over the inner canthus of the eye can reduce absorption. Occluding the nasolacrimal duct in this way for 5 min reduces absorption by up to two-thirds. 103. Concerning non-depolarising muscle relaxants and eye surgery: (a) False; (b) False; (c) False; (d) False; (e) True (a) d-Tubocurarine also causes histamine release and autonomic ganglion blockade, which produce a fall in arterial pressure and reduction in IOP. (b) Rocuronium 0.9 mg kg–1, is given for rapid sequence induction. (c) Vecuronium causes a fall in IOP. (d) The priming technique requires 10–15% of the intubation dose of muscle relaxant to be given pre-induction. (e) Pancuronium is vagolytic. 104. The following should be routinely performed preoperatively for anyone with a pacemaker: (a) True; (b) False; (c) True; (d) False; (e) False Routine tests will usually comprise of a resting ECG, chest
(a) False; (b) False; (c) True; (d) True; (e) True (a) The fourth letter of the NASPE/BPEG code describes rate adaptive functions in permanent pacemakers. (c) Tapping the skin over a pacemaker will simulate movement if the rate adaptation sensor is via a piezoelectric crystal, thus leading to an increase in the pacemaker output rate. 106. Concerning an implantable cardioverter defibrillator: (a) True; (b) True; (c) True; (d) True; (e) True (a) All modern ICDs have a ventricular pacing function to cope with post-defibrillation bradycardia. (c) There is little doubt that more ICDs should be implanted in this country. (d) Further details of driving restrictions can be found in the recently published DVLA standards of fitness to drive. (e) Most early ICDs could be de-activated by a magnet but some of the newer versions may respond unpredictably. 107. Concerning permanent pacemakers: (a) False; (b) False; (c) True; (d) False; (e) True (a) Bipolar electrodes are the least susceptible to electromagnetic interference. (b) Magnet application to PPMs has a variable effect and should not be used. (d) When testing a pacemaker, the threshold is the minimum voltage required to achieve electrical capture. 108. Concerning general anaesthesia for Caesarean section: (a) True; (b) False; (c) False; (d) False; (e) False (a) An emergency is defined as an immediate threat to life of woman or fetus. (b) These opioids effectively attenuate the pressor response to intubation. Neonatal respiratory depression is reversible with naloxone. (c) A maternal stress response to excessively light general anaesthesia will be to the detriment of uteroplacental blood flow and fetal well-being. (d) Magnesium prolongs the duration of action of all non-depolarising drugs but not succinylcholine. (e) Provided that consciousness has been regained and treatment with magnesium sulphate started, regional anaesthesia can be considered. 109. Concerning spinal anaesthesia for Caesarean section: (a) False; (b) True; (c) True; (d) False; (e) False (a) Urgent is defined as maternal or fetal compromise, not immediately life-threatening. Provided repeated attempts are resisted, spinal anaesthesia is acceptable when there is no lifethreatening fetal or maternal compromise. (b) The variability of the level at which the conus medullaris terminates and the inability of anaesthetists correctly to determine their level of approach dictate that spinal needles should not be inserted
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Multiple choice questions and answers
above L3/4. (c) Gestational age affects aortocaval compression, which influences the spread of hyperbaric bupivacaine. (d) Compared with boluses of ephedrine, phenylephrine was associated with greater mean umbilical artery pH. (e) Prior vasodilatation appears to reduce the magnitude of hypotension after spinal anaesthesia. 110. Combined spinal-epidural (CSE) anaesthesia for Caesarean section: (a) False; (b) True; (c) True; (d) True; (e) True (a) Neither improved efficacy nor reduced morbidity has been demonstrated. (b,d) An epidural dose (e.g. of diamorphine) is typically 10 times that of an intrathecal dose. Given that epidural catheters can go astray, it makes sense to use the intrathecal route. (e) Unless a risk of massive haemorrhage has been identified, CSE anaesthesia is appropriate.The epidural catheter will allow extension of anaesthesia in the event of prolonged surgery.
115. In the pre-operative assessment of the elderly: (a) True; (b) True; (c) False; (d) True; (e) True (a) Unfortunately, anaesthetists may miss 25% of abnormalities. (b) This is 2 metabolic equivalents. Less than 4 is associated with postoperative complications. (c) Inotrope-induced testing can be done instead. (d) Deafness is often denied by the patient. (e) Increased care needs to be taken to prevent pressure sores and extravasation of intravenous fluids in a patient with fragile skin. 116. Concerning anaesthesia in the elderly: (a) True; (b) True; (c) True; (d) False; (e) False (a) Closing capacity encroaches on tidal volume when supine after 65 years of age. (b) Mostly due to reduced cough reflexes and increased oesophageal reflux. (c) Indirect acting pressor agents have an unpredictable response. (d) The risk is high. Avoidance of a general anaesthetic may be desirable. (e) The evidence that the elderly are vulnerable to NSAIDs is exaggerated, although care should still be taken.
111. Concerning muscle relaxation in patients with burns: (a) False; (b) True; (c) True; (d) False; (e) False (a) Advice regarding succinylcholine varies, but there is agreement that it can be safely used in the first 24 h. (b,c) This is due to both pharmacokinetic and pharmacodynamic alterations. (d) It is thought to be due to extrajunctional migration of acetylcholine receptors causing increased potassium efflux with succinylcholine. (e) Awake fibre-optic intubation, or gaseous induction are often required if airway difficulty is suspected. 112. Concerning the monitoring of burn patients: (a) False; (b) False; (c) False; (d) False; (e) True (a) The increased dead space will give a spuriously low value for end-tidal CO2. (b,c) Direct myocardial depression is seen post-burn and pulmonary artery flow directed catheters might sometimes be useful. (d) Carbon monoxide toxicity reduces oxygen carriage in the face of a normal PaO2.
113. Concerning the clinical management of burn patients: (a) True; (b) False; (c) True; (d) False; (e) True (b) Ventilated patients are PEEP-dependent. (c) Analgesic regimens should be regularly assessed and tolerance develops quickly. (d) Blood loss during debridement of any burn can be considerable, but it may be up to 3 times greater when infection is present. (e) Even more so than in non-burned patients.
117. The following drugs induce cytochrome P450: (a) False; (b) False; (c) True; (d) False; (e) True (a) Propofol is an inhibitor, although the clinical importance of this remains is controversial. (b) Erythromycin and (d) quinupristin/dulfopristin are inhibitors. 118. Cytochrome(s) P450: (a) False; (b) False; (c) False; (d) False; (e) True (a) They are identified by amino acid homology. (b) They are mostly in the endoplasmic reticulum. (c) These enzymes each metabolise many drugs. (d) They are mostly involved in the transfer of molecular oxygen. 119. These substances are affected by genetic abnormalities of enzymes: (a) False; (b) False; (c) True; (d) True; (e) True (a) It is metabolised by CYP 3A4 which, while it is subject to many causes of variations in its expression, does not appear to have an inactive form. (b) Many enzymes metabolise remifentanil, lack of one of them is unlikely to have any effect on its elimination. 120 The following pathophysiological changes may result in a reduction of enzyme function: (a) True; (b) True; (c) True; (d) True; (e) False (e) High protein, lipid or low carbohydrate diets lead to an increase in some enzymes resulting in enhanced metabolism of some drugs, e.g. theophylline.
114. With respect to the physiology of the elderly: (a) True; (b) True; (c) False; (d) True; (e) False (a) The diagnosis should, therefore, not be made lightly. (c) Some clinicians will consider a ‘fit’ 80-year-old to be ASA 3. (d) Reduced muscle bulk and metabolic capacity also mean that the elderly are unable to easily restore normothermia by shivering. (e) Loss of pacemaker cells to 10% of adolescent levels makes atrial fibrillation the default rhythm.
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121. Which of the following is true: (a) False; (b) False; (c) True; (d) True; (e) True (a) It increases unlike albumin which decreases. (b) CYP 3A4 metabolises this proportion of drugs. (e) For example, paracetamol N-acetyl–p-benzoquinone (NAPQI) is the phase I metabolite of paracetamol that accumulates after an overdose. It is toxic to the liver and kidneys.
British Journal of Anaesthesia | CEPD Reviews | Volume 1 Number 6 2001
