24.1 The clinically used local anaesthetics have the following
common features except:
A. They are amphiphilic weak bases
B. They are used for surgery in non-cooperative patients
C. In their use, care of vital functions is generally not needed
D. They are safer than general anaesthetics in
patients with respiratory and cardiovascular
disease
24.2 The local anaesthetics having amide linkage differ
from those having ester linkage in that the amidelinked
local anaesthetics:
A. Are not surface anaesthetics
B. Have a shorter duration of action
C. Are degraded in the plasma
D. Do not show cross-sensitivity with esterlinked local anaesthetics
24.3 The following is not true of local anaesthetics:
A. The local anaesthetic is required in the
unionized form for penetrating the neuronal
membrane
B. The local anaesthetic approaches its
receptor only from the intraneuronal face of
the Na+ channel
C. The local anaesthetic binds to its receptor
mainly when the Na+ channel is in the
resting state
D. The local anaesthetic combines with its
receptor in the ionized cationic form
24.4 Local anaesthetics block nerve conduction by:
A. Blocking all cation channels in the neuronal membrane
B. Hyperpolarizing the neuronal membrane
C. Interfering with depolarization of the neuronal membrane
D. Both ‘B’ and ‘C’ are correct
24.5 Sensitivity of a nerve fibre to blockade by lignocaine depends on:
A. Whether the fibre is sensory or motor
B. Whether the fibre is myelinated or nonmyelinated
C. Internodal distances in the fibre
D. Both ‘B’ and ‘C’ are correct
24.6 A resting nerve is relatively resistant to blockade by
lignocaine compared to one which is repeatedly
stimulated because:
A. Lignocaine penetrates resting nerve membrane poorly
B. Lignocaine binds more avidly to the inactivated Na+ channel
C. Nerve impulse promotes ionization of lignocaine
D. Nodes of Ranvier are inaccessible in the resting state
24.7 Which of the following is not the reason for greater
susceptibility of smaller sensory fibres to blockade
by local anaesthetics than larger motor fibres:
A. Sensory fibres are inherently more sensitive than motor fibres
B. More slender fibres have shorter internodal distances
C. Small sensory fibres generate higher frequency longer lasting action potential
D. Smaller fibres have shorter critical lengths for blockade
24.8 Which sensation is blocked first by low concentrations of a local anaesthetic:
A. Pain
B. Temperature
C. Touch
D. Deep pressure
24.9 Injection of adrenaline along with a local anaesthetic serves the following purpose:
A. Lowers the concentration of the local anaesthetic to produce nerve block
B. Prolongs the duration of local anaesthesia
C. Increases the anaesthetised area
D. Reduces the local toxicity of the local anaesthetic
24.10 Adrenaline added to local anaesthetic solution for
infiltration anaesthesia affords the following except:
A. Prolongs the duration of local anaesthesia
B. Makes the injection less painful
C. Provides a more bloodless field for surgery
D. Reduces systemic toxicity of the local anaesthetic
24.11 The following local anaesthetic raises BP instead of tending to cause a fall:
A. Cocaine
B. Dibucaine
C. Lignocaine
D. Procaine
24.12 Toxicity of local anaesthetics involves the following organs except:
A. Heart
B. Brain
C. Kidney
D. Skin and subcutaneous tissue
24.13 The local anaesthetic with the longest duration of action is:
A. Procaine
B. Chloroprocaine
C. Lignocaine
D. Dibucaine
24.14 Which of the following is a poor surface anaesthetic:
A. Procaine
B. Lignocaine
C. Tetracaine
D. Benoxinate
24.15 The local anaesthetic having high cardiotoxic and arrhythmogenic potential is:
A. Lignocaine
B. Procaine
C. Bupivacaine
D. Ropivacaine
24.16 Which of the following statements is true for lignocaine:
A. It is an ester-linked local anaesthetic
B. It is not likely to exhibit cross-sensitivity with procaine
C. It has a shorter duration of action than procaine
D. It is not a surface anaesthetic
24.17 Low concentration of bupivacaine is preferred for
spinal / epidural obstetric analgesia because:
A. It has a longer duration of action
B. It can produce sensory blockade without paralysing abdominal muscles
C. It distributes more in maternal tissues so that less reaches the foetus
D. All of the above are correct
24.18 The following local anaesthetic is poorly water soluble,
PABA derivative and primarily used for anorectal
lesions, wounds and ulcers:
A. Benzocaine
B. Dibucaine
C. Procaine
D. Benoxinate
24.19 Choose the local anaesthetic that is specifically
used to produce corneal anaesthesia for tonometry:
A. Tetracaine
B. Oxethazaine
C. Ropivacaine
D. Benoxinate
24.20 Eutectic lignocaine-prilocaine has the following unique property:
A. It causes motor blockade without sensory block
B. By surface application, it can anaesthetise unbroken skin
C. It is not absorbed after surface application
D. It has strong vasoconstrictor action
24.21 Oxethazaine is used for anaesthetizing gastric mucosa because:
A. It is not absorbed from the gastrointestinal tract
B. It remains largely unionized in acidic medium
C. It is highly ionized in acidic medium
D. It produces no systemic effects even at high doses
24.22 Surface anaesthesia is used for the following except:
A. Ocular tonometry
B. Urethral dilatation
C. Tooth extraction
D. Anal fissure
24.23 In which of the following techniques the concentration
of the local anaesthetic used is the lowest:
A. Infiltration anaesthesia
B. Nerve block anaesthesia
C. Spinal anaesthesia
D. Epidural anaesthesia
24.24 The segmental level of spinal anaesthesia depends on:
A. Volume of the local anaesthetic injected
B. Specific gravity of the local anaesthetic solution
C. Posture of the patient
D. All of the above factors
24.25 In spinal anaesthesia the segmental level of:
A. Sympathetic block is lower than the sensory
block
B. Sympathetic block is higher than the sensory block
C. Motor block is higher than the sensory block
D. Sympathetic, motor and sensory block has the same level
24.26 The duration of spinal anaesthesia depends on each
of the following except:
A. Which local anaesthetic is used
B. Concentration of the local anaesthetic used
C. Posture of the patient
D. Whether adrenaline has been added to the local anaesthetic
24.27 The following factor is not involved in the causation
of hypotension due to spinal anaesthesia:
A. Histamine release
B. Reduced sympathetic vasoconstrictor tone
C. Decreased venous return from the lower limbs
D. Bradycardia
24.28 Spinal anaesthesia is not suitable for:
A. Vaginal delivery
B. Lower segment caesarian section
C. Prostatectomy
D. Operations on mentally ill patients
24.29 Epidural anaesthesia differs from spinal anaesthesia in that:
A. Epidural anaesthesia produces less cardiovascular complications
B. Headache is more common after epidural anaesthesia
C. Blood concentrations of the local anaesthetic are lower after epidural anaesthesia
D. Greater separation between sensory and motor blockade can be obtained with epidural anaesthesia
24.30 Intravenous regional anaesthesia is suitable for:
A. Orthopedic manipulations on the upper limb
B. Vascular surgery on the lower limb
C. Head and neck surgery
D. Caesarian section
Ans:
24.1 B 24.2D 24.3 C 24.4 C 24.5D 24.6 B 24.7 A 24.8 A 24.9 B 24.10 B 24.11 A 24.12 C 24.13D 24.14 A 24.15 C 24.16 B 24.17D 24.18 A 24.19D 24.20 B 24.21 B 24.22 C 24.23 A 24.24D 24.25 B 24.26 C 24.27 A 24.28D 24.29D 24.30 A