Topical airway anesthesia for awake fiberoptic intubation: Comparison between airway nerve blocks and nebulized lignocaine by ultrasonic nebulizer

Topical airway anesthesia for awake fiberoptic
intubation: Comparison between airway nerve
blocks and nebulized lignocaine by ultrasonic
nebulizer
Babita Gupta, Santvana Kohli,
Kamran Farooque1,
Gopal Jalwal, Deepak Gupta2,
Sumit Sinha2, Chandralekha
Departments of Anesthesiology
and Intensive Care, 1Orthopedics,
and 2Neurosurgery, All India
Institute of Medical Sciences,
New Delhi, India
A B S T R A C T
Overview: Awake fiberoptic bronchoscope (FOB) guided intubation is the gold standard
of airway management in patients with cervical spine injury. It is essential to sufficiently
anesthetize the upper airway before the performance of awake FOB guided intubation
in order to ensure patient comfort and cooperation. This randomized controlled study
was performed to compare two methods of airway anesthesia, namely ultrasonic
nebulization of local anesthetic and performance of airway blocks. Materials and
Methods: A total of 50 adult patients with cervical spine injury were randomly allocated
into two groups. Group L received airway anesthesia through ultrasonic nebulization
of 10 ml of 4% lignocaine and Group NB received airway blocks (bilateral superior
laryngeal and transtracheal recurrent laryngeal) each with 2 ml of 2% lignocaine and
viscous lignocaine gargles. FOB guided orotracheal intubation was then performed.
Hemodynamic variables at baseline and during the procedure, patient recall, vocal
cord visibility, ease of intubation, coughing/gagging episodes, and signs of lignocaine
toxicity were noted. Results: The observations did not reveal any significant differences
in demographics or hemodynamic parameters at any time during the study. However,
the time taken for intubation was significantly lower in Group NB as compared with the
Group L. Group L had an increased number of coughing/gagging episodes as compared
with Group NB. Vocal cord visibility and ease of intubation were better in patients who
received airway blocks and hence the amount of supplemental lignocaine used was less
in this group. Overall patient comfort was better in Group NB with fewer incidences of
unpleasant recalls as compared with Group L. Conclusion: Upper airway blocks provide
better quality of anesthesia than lignocaine nebulization as assessed by patient recall
of procedure, coughing/gagging episodes, ease of intubation, vocal cord visibility, and
time taken to intubate.
Key words: Airway management, bronchoscopy, laryngeal nerves, lidocaine, nebulizers
Address for correspondence:
Dr. Santvana Kohli,
Department of Anesthesiology and
Intensive Care, All India Institute of
Medical Sciences, New Delhi, India.
E-mail: dr.santvana.kohli@gmail.com
to airway management in most cases of difficult airway,
especially in patients with cervical spine injury. This
technique reduces the risk of neurologic injury before the
onset of surgical procedure.[3] It is essential to sufficiently
anesthetize the upper airway and suppress the gag, swallow
and cough reflexes prior to awake FOB guided intubation
and thus ensure patient comfort.[1,2] This can be achieved
in multiple ways, which can broadly be divided into two
groups: (a) Topical administration of local anesthetic (LA),
or (b) blockade of neural supply to oropharynx and larynx.
Topical administration of LA in the form of sprays, gargles,
lozenges, or impregnated swabs causes fewer trauma to the
oropharyngeal and laryngeal tissues as compared to nerve
blocks. The risk of inadvertent injection into a blood vessel
is also avoided by using this technique. In contrast, nerve
INTRODUCTION
Securing the airway during general anesthesia in patients
with difficult airway poses a risk to the patient and presents
challenges for the anesthesiologists.[1,2] Awake fiberoptic
bronchoscope (FOB) guided intubation is a safe approach
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DOI:
10.4103/1658-354X.144056
O R I G I N A L A R T I C L E
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Gupta, et al.: Comparison between airway blocks and nebulized lignocaine for fiberoptic intubation
Vol. 8 (Supplement 1), November 2014 Saudi Journal of Anesthesia
Page | S16
block techniques typically require a smaller dose of LA
as compared with topical administration of LA, possibly
decreasing the risk of systemic toxicity.
Topical application of LA by nebulization technique is one
of the techniques used to anesthetize the airway. Customary
compressed air driven jet nebulizers atomize only highly
concentrated anesthetics, so that the maximum dose of LA
can be exceeded within a short period of time. Ultrasonic
nebulizer has been designed to deliver liquid medication in
the form of droplets with an average diameter of just 3.5 μm
to the airway. Ultrasonic nebulizers are often used in the
treatment of pulmonary hypertension. Due to the fine mist of
vaporized anesthetics, a remarkably lower dose of lignocaine is
required and hence the probability of toxicity due to overdose
is avoided.[4] It also anesthetizes the trachea beyond glottis.
This randomized controlled study was conducted to assess
and compare the efficacy of ultrasonic nebulization with
nerve block technique to achieve upper airway anesthesia
for awake FOB guided intubation. The findings may
influence clinical practice in the management of the
difficult airway during anesthesia.
MATERIALS AND METHODS
After approval of the protocol by the Institutional
Review Board, 50 adult patients with traumatic cervical
spine injury undergoing cervical spine fixation surgery
were recruited for the study over a period of 12 months.
A written informed consent was obtained from each
patient. Uncooperative patients, those allergic to LA,
asthmatics, epileptics and those with deranged coagulation,
hemodynamic instability, bradyarrhythmias, or infection at
the local site were excluded from the study.
A thorough preoperative evaluation including a complete
airway evaluation (mouth opening, mallampati grading,
thyromental distance, and evaluation of dentition) was
performed. Standard fasting guidelines and anti-aspiration
prophylaxis with tablet ranitidine 150 mg were prescribed.
The patients were explained about the awake FOB guided
intubation during preoperative assessment. Injection
glycopyrrolate 5 μg/kg was given intramuscularly half
an hour before shifting the patient to the operating room
(OR). Inside the OR, standard monitoring, including
electrocardiography (ECG), noninvasive blood pressure
(BP), and pulse oximetry (SpO2) were applied in all patients.
An intravenous (IV) line was secured and ringer lactate
was started. An arterial line was established under local
anesthesia. After recording the baseline heart rate (HR),
BP and SpO2, injection midazolam 20 μg/kg and injection
fentanyl 1 μg/kg were given IV.
The patients were randomly allocated into two groups.
Randomization was done using computer generated tables
of random numbers. Group L (n = 25) received 10 ml of
4% lignocaine by ultrasonic nebulizer (LD 10185, Honsun,
Shanghai, China) for 15 min, and Group NB (n = 25)
received bilateral superior laryngeal nerve and transtracheal
instillation of 2 ml of 2% lignocaine, along with viscous
xylocaine gargles twice. Adequate effect of local anesthesia
was confirmed by heaviness of tongue in Group L patients
and by hoarseness of voice in Group NB patients.
While giving supplemental oxygen through nasal prongs,
FOB guided intubation was performed. Size 8.0 mm
internal diameter endotracheal tube was used for male
patients and 7.5 mm for female patients. Vital parameters
(HR, BP, and SpO2) were also recorded during intubation
and at 1 min and 3 min postintubation. Supplemental LA
was given as 1 ml aliquots of 2% lignocaine through the
working channel of FOB (next aliquot given only after
waiting for 30-60 s). Other parameters such as gag/cough
reflex, cord visibility (relaxed, partially relaxed or adducted
on endoscopic view), and ease of intubation [Table 1]
were also recorded. Any signs of lignocaine toxicity such
as ECG changes, seizures, and bronchoconstriction were
also noted. After the airway was secured, general anesthesia
was administered with propofol 2 mg/kg, and rocuronium
0.6 mg/kg. Postoperatively, patient comfort was assessed
for complete amnesia, partial recall, and unpleasant
memories during awake FOB guided intubation.
All data were tabulated and analyzed statistically. Parametric
values were reported as mean ± standard deviation.
Hemodynamic variables were compared using the unpaired
Student’s t-test. Intubation grades and patient comfort
scores were compared using the Mann — Whitney U test.
Statistical significant value was considered if P < 0.05.
RESULTS
The demographic data [Table 2] showed no significant
differences between the two groups. There was no
statistically significant difference between both groups
at any interval for HR or BP [Figure 1]. Patients in both
Table 1: Grades of intubating condition
Grade of intubating
conditions
Description
Optimal No collision (hold-up) encountered
Suboptimal Hold-up, relieved by rotation of the tube once
Difficult Hold-up, requiring more than one rotation of the tube
or alteration in the patient’s head or neck position
Failure Failure of the attempt at FOB guided tracheal
intubation
FOB: Fiberoptic bronchoscope
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Gupta, et al.: Comparison between airway blocks and nebulized lignocaine for fiberoptic intubation
Saudi Journal of Anesthesia Vol. 8 (Supplement 1), November 2014
Page | S17
Group NB [Figure 2]. It was due to this reason that
supplemental lignocaine had to be used in significantly
more number of patients in Group L as compared with
Group NB (n = 16 in Group L as compared to n = 5 in
Group NB, P = 0.009). The mean supplemental lignocaine
volume used was 1.06 ± 0.87 ml and 0.6 ± 0.64 ml in
Group L and Group NB, respectively. This difference was
statistically significant (P = 0.004). The highest quantity of
supplemental lignocaine used in a single patient was 4 ml
in Group L (n = 1) and 2 ml in Group NB (n = 3).
The vocal cord visibility [Figure 3] was better in Group NB
as compared to Group L (P = 0.006). Only three patients
in Group L had completely relaxed vocal cords as opposed
to 12 patients in Group NB. Partially relaxed vocal cords
were observed in seven patients in Group L and 11
patients in Group NB. Completely adducted vocal cords
were seen in 12 patients in Group L. However, this did not
have much impact on the ease of intubation [Figure 4],
probably because of supplemental LA instillation. There
groups exhibited a slight decrease in SpO2 during the
procedure, but the lowest SpO2 recorded was 92%. All the
patients remained sufficiently awake to cooperate with the
procedure and none of the patients showed any evidence
of lignocaine toxicity.
Awake FOB guided intubation was accomplished in
all patients in both groups and in no patient was the
procedure abandoned due to discomfort. The time taken
to perform FOB guided intubation was less in Group NB
(123.0 ± 46.7 s) as compared with Group L (200.4 ± 72.4 s)
and this was statistically significant [Table 2]. Significantly
more number of patients experienced gag and coughing
during the procedure in Group L as compared with
Figure 1: Comparison of hemodynamic variables between the two
groups at baseline, 1 min and 3 min after intubation
Figure 2: Comparison between the number of patients experiencing
coughing/gagging in each group
Figure 3: Comparison of vocal cord visibility between the two groups
Figure 4: Comparison of the intubating conditions between the two
groups (no failure was encountered)
Table 2: Demographic data and time taken for
FOB guided intubation
Group A Group B P value
Age (years) 39.9±10.4 39.8±8.0 0.964
Sex (male/female) 23/1 21/4 0.171
Weight (kg) 61.4±3.8 57.0±10.0 0.480
Time for FOB (s) 200.4±72.4 123.0±46.7 0.047
FOB: Fiberoptic bronchoscope
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Gupta, et al.: Comparison between airway blocks and nebulized lignocaine for fiberoptic intubation
Vol. 8 (Supplement 1), November 2014 Saudi Journal of Anesthesia
Page | S18
Administration of lignocaine through nebulization for
anesthesia of upper airway and larynx has also been
previously studied. In their study Cullen et al.[6] found
that lignocaine nebulization decreased the discomfort of
nasogastric tube insertion. In 2007, Techanivate et al.[7]
found adequate upper airway anesthesia with 2% lignocaine
nebulization and topical cocaine application to the nose for
fiberoptic nasotracheal application.
In our study, the time taken to perform FOB guided
intubation was significantly more in the nebulization group
as compared to the nerve blocks group. Our results are
contradictory to the randomized double-blinded study
conducted in 1995 by Reasoner et al.,[3] which compared
nebulized lignocaine with airway blocks to aid in FOB guided
intubation in patients with cervical spine instability. The
topical anesthesia group received 20 ml of 4% lignocaine
via nebulization followed by a 3 ml transtracheal injection.
On the other hand, the nerve block group received bilateral
glossopharyngeal and superior laryngeal nerve blocks along
with the transtracheal injection. They found no significant
difference in the time taken to intubate between the groups.
This was probably because nebulization was supplemented
by transtracheal injection of 3 ml lignocaine, which further
improved the quality of anesthesia.
Kundra et al.[8] also compared two methods of anesthetizing
the airway for awake fiberoptic nasotracheal intubation.
One of the groups received 4 ml of 4% lignocaine
through nebulization and the other received airway blocks
(translaryngeal, bilateral superior laryngeal and lignocaine
soaked cotton swabs in the nose). Although the time
taken to intubate was similar in both groups, patients who
received lignocaine nebulization for airway anesthesia had
to undergo significantly higher stress during the insertion of
endotracheal tube through the glottis. The grimace scores
as well as the mean HR and BP in the nebulization group
were significantly higher during endotracheal tube insertion.
Patient comfort was better in the nerve blocks group as
compared with the nebulization group in our study, as
deduced by the coughing/gagging episodes as well as the
patient assessment of procedure recall. These findings
are similar to those reported by Graham et al.[9] in 1992.
They compared three different methods to provide airway
anesthesia during FOB. All patients received benzocaine
lozenges, lignocaine sprays for posterior pharynx and
lignocaine jelly for nasal passages along with either 4 ml
of 2.5% cocaine injection through FOB working channel,
transtracheal injection of the same amount of cocaine or
nebulized 4 ml of 4% lignocaine. They reported that the
transtracheal injection of cocaine provided significantly
superior patient comfort and less coughing episodes as
compared with the rest of the techniques. The findings
was no statistical difference in between the two groups
regarding the intubating conditions (P = 0.315). Patient
comfort was also significantly different between the
two groups [Figure 5]. Only six patients in Group L
reported complete amnesia as compared to 13 patients
in Group NB. No patient in Group NB reported recall
of unpleasant memories as compared with six patients
in Group L (P = 0.007).
DISCUSSION
Awake tracheal intubation with the aid of a fiberoptic
device was first described by Murphy in 1967,[5] who used
a choledochoscope to facilitate nasotracheal intubation
in patients with difficult airway. Since then, numerous
subsequent authors have described the anesthetic
techniques and experiences with awake FOB guided
intubation. It offers several advantages over use of FOB
after induction of general anesthesia in patients with
cervical spine instability:
a. Patient remains in a neutral position, minimizing the
risk of neurological deterioration;
b. patient’s neurological status can be assessed after
intubation, and
c. spontaneous ventilation is preserved.[3]
There are multiple ways of anesthetizing the airway
to facilitate the performance of awake FOB guided
intubation. Among them, topical anesthesia with
nebulized LA, gargles, lozenges, sprays, airway blocks and
LA through the working channel of FOB is commonly
used. Although the above-mentioned techniques can
be combined in various ways, we chose two mutually
exclusive techniques to compare their efficacy and patient
comfort. There is a paucity of literature comparing the
efficacy and safety for such methods in a population with
cervical spine fixation surgery.
Figure 5: Comparison between the patient comfort and degree of recall
of events during fiberoptic bronchoscope guided intubation
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Gupta, et al.: Comparison between airway blocks and nebulized lignocaine for fiberoptic intubation
Saudi Journal of Anesthesia Vol. 8 (Supplement 1), November 2014
Page | S19
reported by Reasoner et al.[3] were also similar. Although,
there was no difference in the number of coughing/
gagging episodes between the two study groups, patient
recall of the procedure was more in the nebulization
group. Kundra et al.[8] also reported higher grimace scores,
mean HR and BP during insertion of endotracheal tube
in patients who received lignocaine via nebulization as
compared to nerve blocks. However, the patient comfort
and recall of the procedure were comparable between the
two groups.
In our study, vocal cord visibility and ease of intubation
as assessed by the bronchoscopist were better in the
nerve block group as compared with the nebulization
group. This finding is similar to that observed by Graham
et al.[9] They reported that the bronchoscopist preferred
transtracheal instillation of LA as compared to LA
nebulization or LA instillation through the working port
of FOB. However, Reasoner et al.[3] did not find any
difference in the quality of airway anesthesia between
nebulized LA and nerve blocks as assessed by a blind
observer/bronchoscopist.
Gal[10] reported that lignocaine mist produced as an
aerosol during ultrasonic nebulization causes airway
irritation in subjects as evidenced by coughing. Later
however, it results in bronchodilatation due to its
membrane stabilizing action. No such adverse effects
caused by lignocaine mist were noted in our study.
The maximum total dose of lignocaine used in our study was
400 mg through nebulization. Such a dose of lignocaine has
been safely used and reported for FOB in many previous
studies. In 1997, Parkes et al.[11] used 6 mg/kg of 10%
lignocaine solution through nebulization mask for fiberoptic
intubation. The serum lignocaine levels measured remained
below the accepted threshold of 5 mg/l at all times (highest
levels obtained were 0.45 mg/l). Similarly, Langmack et al.[12]
measured the serum lignocaine levels in 51 asthmatic
volunteers undergoing FOB with topical lignocaine. The
average total dose used was 600 mg (8.2 mg/kg), which
was found to be safe in all patients as assessed by serum
lignocaine concentrations. However, in 1993, Wu et al.[13]
have reported seizures in a patient after administration of
a total dose of 300 mg of topical lignocaine during FOB.
The serum lignocaine concentrations were found to be well
above the acceptable toxic limits. Hence, a constant lookout
for signs and symptoms of lignocaine toxicity is mandatory
while using large doses.
The limitations of our study are that it is an unblinded
study allowing some amount of bias. Furthermore, serum
lignocaine levels were not measured due to nonavailability
of this facility at our center.
Given the results of the study and the above discussion,
the following conclusions may be drawn. The performance
of bilateral superior laryngeal and transtracheal recurrent
laryngeal nerve blocks provides adequate airway anesthesia
to aid in awake FOB guided intubation. Furthermore,
10 ml of 4% lignocaine through ultrasonic nebulizer may
not provide acceptable conditions for bronchoscopy, but
a higher dose might be able to adequately anesthetize
the airway. However, a lower dose of lignocaine through
nebulization along with supplemental lignocaine instillation
through the working channel of FOB might provide
adequate airway anesthesia. More studies need to be
performed to determine the amount of lignocaine, which
can be used for nebulization with serum lignocaine levels.
REFERENCES
1. Benumof JL. Management of the difficult adult airway.
With special emphasis on awake tracheal intubation.
Anesthesiology 1991;75:1087-110.
2. Barash PG, Cullen BF, Stoelting RK. Clinical Anesthesia.
5th ed. Philadelphia: Lippincott Williams & Wilkins; 2006. p.
621-30.
3. Reasoner DK, Warner DS, Todd MM, Hunt SW, Kirchner J.
A comparison of anesthetic techniques for awake intubation
in neurosurgical patients. J Neurosurg Anesthesiol 1995;7:
94-9.
4. British Thoracic Society Bronchoscopy Guidelines Committee, a
Subcommittee of Standards of Care Committee of British Thoracic
Society. British Thoracic Society guidelines on diagnostic flexible
bronchoscopy. Thorax 2001;56 Suppl 1:i1-2.
5. Murphy P. A fibre-optic endoscope used for nasal intubation.
Anesthesia 1967;22:489-91.
6. Cullen L, Taylor D, Taylor S, Chu K. Nebulized lidocaine decreases
the discomfort of nasogastric tube insertion: Arandomized,
double-blind trial. Ann Emerg Med 2004;44:131-7.
7. Techanivate A, Leelanukrom R, Prapongsena P, Terachinda D.
Effectiveness of mouthpiece nebulization and nasal swab stick
packing for topical anesthesia in awake fiberoptic nasotracheal
intubation. J Med Assoc Thai 2007;90:2063-71.
8. Kundra P, Kutralam S, Ravishankar M. Local anesthesia for
awake fibreoptic nasotracheal intubation. Acta Anaesthesiol
Scand 2000;44:511-6.
9. Graham DR, Hay JG, Clague J, Nisar M, Earis JE. Comparison
of three different methods used to achieve local anesthesia
for fiberoptic bronchoscopy. Chest 1992;102:704-7.
10. Gal TJ. Airway responses in normal subjects following topical
anesthesia with ultrasonic aerosols of 4% lidocaine. Anesth
Analg 1980;59:123-9.
11. Parkes SB, Butler CS, Muller R. Plasma lignocaine
concentration following nebulization for awake intubation.
Anaesth Intensive Care 1997;25:369-71.
12. Langmack EL, Martin RJ, Pak J, Kraft M. Serum lidocaine
concentrations in asthmatics undergoing research
bronchoscopy. Chest 2000;117:1055-60.
13. Wu FL, Razzaghi A, Souney PF. Seizure after lidocaine for
bronchoscopy: Case report and review of the use of lidocaine
in airway anesthesia. Pharmacotherapy 1993;13:72-8.
How to cite this article: Gupta B, Kohli S, Farooque K, Jalwal G,
Gupta D, Sinha S, C. Topical airway anesthesia for awake fiberoptic
intubation: Comparison between airway nerve blocks and nebulized
lignocaine by ultrasonic nebulizer. Saudi J Anaesth 2014;8:15-9.
Source of Support: Nil, Conflict of Interest: None declared.
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107

104, 105

MCQs Q.74 To Q.103

Q.74 Regarding two compartment  pharmacokinetics:
a) a drug is always removed from the peripheral compartment
b) the central compartment is blood volume
c) a drug with a high volume of distribution is likely to be lipophillic
d) a drug can have a short duration of action while being eliminated very slowly
e) most anaesthetic drugs are modelled well with a two-compartment model

Q.75 Desflurane:
a) is a fluorinated methylisopropyl ether
b) boils at 23 degrees C
c) is safe to use in patients with malignant hyperpyrexia
d) stimulates the sympathetic system when inspired concentration is suddenly increased
e) prolongs the duration of muscle relaxants

Q.76 Regarding the use of suxamethonium:
a) bradycardia is a complication
b) phase II block occurs more commonly with neonates
c) prolonged duration of action may be seen in around one patient in 40
d) can raise the serum potassium by 0.5 mmol/ L
e) dose required is lower in small children

Q.77 Concerning electroencephalography (EEG):
a) voltages are in the range of 10-100 millivolts
b) spontaneous EEG activity is lost when the body temperature drops below 25 degrees C
c) b waves are enhanced by sedatives
d) d waves only occur in brain injury
e) q waves occur at a frequency of 4-7 Hz

Q.78 Action potentials:
a) are all or none signals of about 100 mV in amplitude
b) are generated by leakage of K+ down their concentration gradient
c) are normally conducted antidromically
d) summate at high frequencies
e) depend on the size of the stimulus

Q.79 Conduction velocity of a nerve impulse:
a) is greater in C fibres than in group A fibres
b) is greater in large diameter nerve fibres
c) is greater in unmyelinated nerve fibres because of saltatory conduction
d) can be as fast as 120 m/s in human nerve fibres
e) is decreased in hypothermia

Q.80 Regarding drug metabolism by cytochrome P450 isoenzymes:
a) cytochrome P450 makes up 1% of total liver proteins
b) the most important enzyme is CYP3A4
c) the system is responsible for most of the reductive metabolism in humans
d) volatile anaesthetics are metabolised by CYP2E1
e) some isoenzymes are inhibited strongly by erythromycin

Q.81. Atropine:
a) may cause bradycardia
b) dilates the pupil in premedicant dose
c) has a shorter duration of action than glycopyrrolate
d) increases the physiological dead space
e) has both muscarinic and nicotinic effects

Q.82. In the pulmonary circulation:
a) capillary hydrostatic pressure is about 25 mmHg
b) 50% of the cardiac output goes to the pulmonary circulation in the foetus
c) angiotensin is broken down
d) bradykinin is inactivated
e) hypoxia causes vasoconstriction

Q.83 Regarding local anaesthetic agents (LA):
a) the potency of LAs is proportional to their lipid solubility
b) the duration of action is dependent on protein binding
c) agents with low pKa have a faster onset of action
d) all local anaesthetics are vasodilators
e) the depth of local anaesthetic block is increased by increasing the dose

Q.84. Cisatracurium besylate:
a) is a mixture of three stereoisomers
b) in equipotent doses has a similar duration of action to vecuronium
c) is less potent than atracurium
d) undergoes more Hoffmans degradation than atracurium
e) in equipotent doses has a similar onset time to atracurium

Q.85. If an electric current is fed through the body:
a) risk of injury is largely dependent upon the current flow
b) antistatic shoes provide good protection due to their high resistance
c) high frequencies are more dangerous than low frequencies
d) ventricular fibrillation occurs at a lower current in patients with dysrhythmias
e) a tingling sensation is felt at a current strength of 1 mA

Q.86. The countercurrent concentrating mechanism in the kidney:
a) depends on active transport of sodium and chloride out of the ascending loop of Henle
b) allows an osmolality of 1200 mosmoles/kg in distal tubules
c) occurs predominantly in the cortical nephrons
d) relies on the free movement of water and electrolytes across the walls of the vasa recta
e) depends on a low concentration of urea in the medullary interstitium

Q.87 The adverse effects of NSAIDs on the kidney:
a) are reversible in normal kidneys
b) are not dose related
c) are mediated by inhibition of PGI2 synthesis
d) may cause acute interstitial nephritis
e) are counteracted by the use of ACE inhibitors

Q.88 The following trigger the secretion of antidiuretic hormone from the posterior hypothalamus:
a) a 5% reduction in extracellular fluid
b) chronic renal failure
c) anxiety
d) supine position
e) head injury

Q.89. Concerning the measurement of oxygen:
a) an oxygen electrode should be calibrated at zero and in room air
b) oxygen tension in a liquid can be measured with a Clark electrode
c) a polarographic electrode can be used in vivo
d) oxygen measurement in a gas mixture makes use of the magnetic property of oxygen
e) a fuel cell has a rapid response to change in oxygen concentration

Q.90 Drug clearance:
a) is the amount of drug removed from plasma in unit time
b) is proportional to half-life
c) is low in lipid-soluble drugs
d) occurs only in the liver and kidney
e) is calculated by dividing the dose of drug given by area under plasma concentration-time curve

Q.91 The volume of distribution of a drug:
a) is low if the drug is highly protein bound
b) can be calculated by multiplying half-life by natural logarithm of 2
c) is relatively low for muscle relaxants
d) is proportional to half life
e) is dependent on the elimination rate constant

Q.92 Concerning composition of body fluids:
a) plasma constitutes a quarter of extracellular fluid (ECF) volume
b) ECF volume may be grossly depleted in intestinal obstruction
c) the protein content of interstitial fluid is higher compared with intracellular fluid (ICF) and plasma
d) the ratio of ECF/ICF volume is smaller in infants and children
e) the normal osmolality of plasma is 280 mosmoles/kg

Q.93 Aldosterone causes:
a) a decrease in urine sodium concentration
b) weight gain
c) decreased serum chloride level
d) increased extracellular fluid volume
e) increased K+ excretion

Q.94 The following antibiotics have good activity against anaerobic bacteria:
a) vancomycin
b) aztreonam
c) metronidazole
d) imipenem
e) trimethoprim

Q.95 Flumazenil:
a) may induce panic attacks in susceptible patients
b) has anticonvulsant activity in patients with epilepsy
c) has a long duration of action
d) may cause nausea and vomiting
e) has inverse agonist action at benzodiazepine receptors

Q.96 Concerning the blood brain barrier (BBB):
a) it is virtually impermeable to ions and proteins
b) it breaks down around brain infarcts
c) a rise in serum albumin by 20 g/L will draw more H₂O across the BBB than a rise in serum Na+ by 5 mmol/L
d) when damaged, cytotoxic brain oedema results
e) mannitol crosses the BBB easily

Q.97 Osmolality:
a) is the number of osmotically active particles per litre of solvent
b) of urine is similar to that of plasma in chronic renal failure
c) may be estimated by formula 2X(Na+K) + Blood sug + BUN
d) is measured by amount of depression of the freezing point
e) is a part of colloid oncotic pressure

Q.98. ABO compatibility is essential for transfusion of:
a) SAGM blood
b) haemoglobin solutions
c) cryoprecipitates
d) FFP
e) platelets

Q.99 The following increase during pregnancy:
a) plasma volume
b) fibrinogen
c) gastric emptying time
d) glucose tolerance
e) arterial PaCO₂

Q.100. Carbon monoxide:
a) binds to haemoglobin with 100 times the affinity of oxygen
b) results in the oxyhaemoglobin curve shifting to the left
c) poisoning can be reliably detected by pulse oximetry
d) levels in normal non-smokers is 10-15%
e) concentration in circle is increased during desflurane anaesthesia

Q.101. Resting potential across the nerve membrane:
a) depends largely on the ratio of K+ inside and outside the cell
b) is positive inside with respect to outside
c) is of the order of 0.06 volt
d) decreases in magnitude during prolonged hypoxia
e) is greater the larger the diameter of the nerve fibre

Q.102 Activation of NMDA receptors:
a) is important in learning and memory
b) can result in neuronal damage
c) is involved in the development of opioid tolerance
d) causes opening of the chloride channel
e) may increase the intensity of pain

Q.103. Bacteria develop resistance to antibiotics:
a) by changing permeability of porin channels in cell wall
b) by producing enzymes to inactivate antibiotics
c) by altering target sites (DNA gyrase and topoisomerase) for antibiotics
d) by active extrusion of antibiotic once it enter the cell
e) easily in presence of necrotic tissue

MCQs Q.1 To Q.73

Q.1 In sickle cell disease
a)      At least 50 per cent of the red cell haemoglobin is in the fetal form of HgB (Hb F)
b)      Dactylitis is an early sign in infancy
c)      Splenomegaly is a characteristic finding in adults
d)      Iron therapy is valuable if the patient is anaemic
e)      Travel in an un-pressurised aircraft can precipitate a sickling crisis

Q.2 In cautious use of oxygen in high concentrations in patients with chronic bronchitis is liable to
a)      Cause cataract formation
b)      Lead to a rise in intracranial pressure
c)      Be associated with a coarse flapping tremor
d)      Reduce alveolar ventilation
e)      Cause low molecular weight proteinuria


Q.3 A plasma bicarbonate level of 32 mEq/1 is consistent with
 a)      Hypokalaemia
b)      Persistent vomiting due to pyloric stenosis
c)      Diabetic ketoacidosis
d)      Chronic cor pulmonale
e)      Chronic renal failure



Q.4 Accidental hypothermia with a core temperature below 30 C may cause
a)      Metabolic acidosis
b)      J waves in the electrocardiogram
c)      Ventricular fibrillation
d)      A rise in serum amylase
e)      Hyperglycaemia


Q.5 Acutely reducing the inspired oxygen concentration to 10% at sea level can cause
a)      Decreased urinary pH
b)      Increased cardiac output
c)      Decreased binding capacity of Hb for oxygen
d)      A respiratory alkalosis
e)      Increased erythropoietin secretion


Q.6 Administration of oxygen in hypovolaemic shock
a)      Increases the PaO2
b)      Decreases the physiological shunt
c)      Decreases alveolar dead space
d)      Increases pulmonary vascular resistance
e)      Increases the dissolved oxygen content of blood

   Q.7 The following decrease uterine muscle tone

a)      A.D.H
b)      Salbutamol
c)      Halothane
d)      PGF2-alpha
e)      Amyl nitrite

Q.8 Factors speeding induction with an inhalational agent include;-
a)      An opiate premedication
b)      Decreased cardiac output
c)      Increased alveolar ventilation
d)      Substitution of an agent with higher blood gas solubility
e)      Increased inspired carbon dioxide concentration

Q.9 Ketamine induced hallucinations and delirium
a)      Can be decreased by a benzodiazepine premedication
b)      Are less common in children
c)      Are less common after short surgical procedures
d)      Are less following IM administration
e)      Are caused only by its metabolites

 Q.10 Prilocaine

a)      Is 70% protein bound
b)      Is an amide
c)      Is used in eutectic mixtures
d)      Is metabolised by plasma cholinesterase
e)      Is more  toxic than lignocaine at the same dose

Q.11 D-tubocurare
a)      Is monoquaternary
b)      Is a ganglion blocker
c)      Is excreted into bile
d)      Causes histamine release
e)      Blocks the cardioinhibitory nerve supply to the heart.

Q.12 Alphs I Acid Glycoprotein
a)      Is increased in burns, trauma, malignancy and post MI.
b)      Is decreased in neonates, pregnancy and with the oral contraceptive.
c)      Is synthesised in the liver.
d)      Binds Atenolol.
e)      Significantly modifies the free fraction of propranolol


 Q.13 Causes of the anticoagulant effect of a massive blood transfusion includes:-

a)      Deficient factor V and VIII
b)      Inactive platelets
c)      Microaggregates
d)      Cold
e)      Vitamin K antagonism

Q.14 The following are recognised causes of a raised fasting serum triglyceride concentration:
a)      High ethanol intake
b)      Treatment with propranolol
c)      Treatment with nifedipine
d)      Chronic renal failure without proteinuria
e)      Treatment with cholestyramine

Q.15 The radial artery
a)      Is the main artery forming the deep palmar arch.
b)      Is medial to the radial nerve at the wrist
c)      Supplies al the digits
d)      Is  superficial to extensor pollicis longus tendon.
e)      Enters the palm between the heads of the first dorsal interosseous muscle.


Q.16 The following are the main buffers of hydrogen ions in the blood:
a)      Haemoglobin
b)      Ammonium ions
c)      Phosphate
d)      Bicarbonate
e)      Plasma proteins

Q.17 Hyponatraemia may be seen with the following:
a)      Addison’s disease
b)      Renal disease
c)      Congestive cardiac failure
d)      Use of diuretics such as frusemide
e)      Carcinoma of the lung

Q.18 The left recurrent laryngeal nerve;
a)      Hooks round the arch of the aorta
b)      Hooks round the subclavian artery
c)      Is related intimately to the superior thyroid artery
d)      Runs between the oesophagus and trachea
e)      Section causes abduction of the cords


Q.19 The following conditions are likely to causes serious complications during pregnancy:
a)      Mitral stenosis
b)      Secundum atrial septal defect
c)      Ventricular septal defect with normal pulmonary artery pressure
d)      Primary pulmonary hypertension

Q.20 The heart rate is increased by;-
a)      Raised intracranial pressure
b)      Inspiration
c)      Moving ot the upright position from lying down
d)      Adrenaline
e)      Stimulation of the pain fibres of the trigeminal nerve.

Q.21 Reduced urine output during major surgery is due to
a)      Catecholamine release
b)      Rennin-aldosterone system
c)      Supine posture
d)      Hypotension
e)      ADH


Q.22 Halothane
a)      Forms bromide
b)      Has 4 fluoride atoms
c)      Has MAC of 1.5 vol % at one atmosphere
d)      Is a coronary vasodilator
e)    Is a suitable agent for single breath induction

Q.23 Isoflurane
a)      Is inflammable at high (oxygen)
b)      Slows AV conduction at clinical concentration
c)      Is a  methyl-ethyl ether
d)      Is more potent than enflurane
e)      Is a coronary vasodilator

Q.24 Alfentanil
a)      Produces analgesia without sedation
b)      Induces convulsions
c)      Is more protein bound than morphine
d)      Has a lower Vd than fentanyl
e)      Is more potent than fentanyl

Q.25 A total body potassium deficit due to gastro-intestinal loss may be consistent with:-
a)      A normal serum K_
b)      Normal adrenals and kidneys
c)      And acid urine
d)      Increased bicarbonate

Q.26 Ptosis may be caused by damage to:-
a)      The occulomotor nerve
b)      The trigeminal nerve
c)      The cervical sympathetic ganglion
d)      The abducens nerve
e)      The parasympathetic system

Q.27 Paroxysmal ventricular tachycardia can be arrested by:-
a)      Disopyramide
b)      Lignocaine
c)      Digoxin
d)      Phenoperidine
e)    Magnesium

Q.28 Regarding innervations of uterus and birth canal
a)      Analgesia/anaesthesia of the birth canal can be effected by a pudendal block
b)      The sensory innervation of the uterus is carried via sympathetic efferents to L2
c)      Increase in gamma efferent activity will increase uterus tone.
d)    Nitrites influence uterine tone by there effect on parasympathetic system
e)    Lignocaine with adrenaline is safe in pudendal nerve block

Q.29 Tendon jerks of the lower limb
a)      Are increased with ventral horn lesions
b)      Are increased with a lesion in the contralateral motor-cortex
c)      Are increased with a lesion in the ipsilateral spinothalamic tract
d)      Are increased with lesions of upper motor neurones
e)   Are uninfluenced by lesions in the extra-pyramidal system

Q.30 In patient with severe hypovolaemia
a)  The physiological dead space is increased
b)  Arterio-venous oxygen difference is decreased
c)  Renal blood flow is diminished
d)  Ventilation is usually depressed
e)  Carbon dioxide retention occurs

Q.31 The serum potassium concentration:-
a)      In a normal subject is increased suxmethonium
b)      Is increased by thiopentone
c)      Influences the toxicity of digoxin
d)      Is lowered in extensive burns
e) Is increased by hyperventilation

Q.32 In a patient with oedema due to cardiac failure there is:-
a)      Increased sympathetic nervous activity.
b)      Increased plasma rennin activity
c)      Reduced sodium reabsorption  by the renal tubules.
d)      Increase serum sodium
e)      An interstitial fluid volume of about 10L

Q.33 The following increase the speed of induction with an inhalational agent:-
a)   Opiate pre-medication
b)      Increased alveolar ventilation
c)      Increased cardiac output
d)      Replacing it with an agent that has a blood / gas solubility twice that of the one in use
e)      The second gas effect

Q.34 Lignocaine
a)      Decreases nitrous oxide requirements
b)      Is metabolised by liver esterases
c)      Its clearance is reduced by constant IV infusion for 24 hours
d)      Causes a decrease in the resting membrane potential
e)      Affects potassium ion flux during the action potential.

Q.35 Alveolar uptake of anaesthetic gas is dependent on
a)      Blood solubility of the agent
b)      Potency of the agent
c)      Alveolar ventilation inspired concentration of the agent
d)      Venous concentration of the agent
e)   Fresh gas flow

 Q.36 The following are positive ionotropes:-

a)      Verapamil
b)      Potassium
c)      Propranolol
d)      Elucagon
e)      Theophylline

      Q.37 The following have a blood/ gas solubility less than 2

a)      Cyclopropane
b)      Nirous oxide
c)      Halothane
d)      Isoflurane
e)      Trilene

Q.38 Isoflurane is:-
a)      A fluorinated hudrocarbon
b)      Has a MAC of 0.5 in 70% N20
c)      Causes less respiratory depression than halothane
d)      Should not be used with sodalime
e)      Has a greater oil/gas solubility than halothane

Q.39 Concerning intravenous regional anaesthesia:-
a)      Up to 30 mls of 1% lignocaine may be used
b)      Systemic side effects may occur despite an effective tourniquet
c)      Prilocaine 1% is contraindicated
d)      May be used on the lower limb.
e)   Works as long as tourniquet is in place

Q.40 The following are true concerning ABO blood
a)      In an individual three allelic genes determine blood groups
b)      Genotype is determined by serological tests
c)      Blood group may change during bone marrow transplantation
d)      Subgroup incompatibility may cause severe transfusion reactions
e)      Antibodies to blood group substances A and B occur naturally
 Q.41 The following occur as a response to major surgery:-
a)      Natriuresis
b)      Hypocalcaemia
c)      Reduced Lipolysis
d)      Increased peritoneal uptake.
e)      Potassium retention.

Q.42 The following increase in normal pregnancy:-
a)      Plasma albumin
b)      Blood urea
c)      ESR
d)      Serum thyromine
e)      Serum uric acid.

Q.43 The following drugs should be avoided in renal failure:-
a)      Gentamicin
b)      Doxycycline
c)      Aluminium hydroxide
d)      Frusemide
e)      Nirtofurantoin.

Q.44 In tardive dyskinesia:-
a)      The condition can be caused by metoclopramide
b)      Symptoms can be exacerbated by emotional stress
c)      Is due to hypersensitivity of dopamine receptors
d)      Anticholinergic drugs are a useful therapy.
e)      The lesion is in the cerebellum.

Q.45 Anaphylactic and anaphylactoid reactions.
a)      Anaphylactoid reactions commoner than anaphylactic
b)      Bronchospasm is a common feature of anaphylaxis
c)      Hydrocortisone is a first line drug
d)      Muscle relaxants are commonest triggering agents during anaesthesia
e)      Thiopentone more likely to cause anaphylactic type reaction



Q.46 Post-op nausea and vomiting.
a)      Five times commoner in females
b)      Increases with increasing age
c)      Commoner with Propofol than thiopentone
d)      Isoflourane least emetogenic of the inhalational agents
e)      Ondansetron clearance significantly reduced in renal failure

Q.47 Massive transfusion of filtered blood may lead to:-
a)      Hypothermia
b)      Increased plasma ionised calcium
c)      Hypokalaemia
d)      Right shift of oxyhaemoglobin dissociation curve
e)        Metabolic acidosis

Q.48 Congenital diaphragmatic hernia
a)      Presents usually bilateral
b)      Presents usually in the first day or two of life
c)      Is not a contraindication for use of N20.
d)      May usually be diagnosed by CXR
e)   has a better prognosis than Traceho-oesophgeal Fistula

 Q.49 Characteristic features of the re-feeding syndrome include:-

a)      Acute hypophosphataemia.
b)      Glycosuria
c)      Decreased red cell survival.
d)      Reduced S.V.R
e)      Parasthesia

Q.50 Features of acute post-infective polyneuropathy includes:
a)      Frontal balding
b)      Sympathetic neurone involvement
c)      Weakness of upper motor neuron type.
d)      Invariable progression of ventilation
e)      Normal CSF protein.
 Q.51 Regarding Reflex sympathetic dystrophy.
a)      Osteoporosis common
b)      Dysaesthesia a feature
c)      Cryoablation is useful
d)      Trophic changes occur rarely
e)      May follow trivial injury.

Q.52 Trigeminal Neuralgia
a)      Radiofrequency lesioning via foramen rotundum is effective
b)      Typically produces altered sensation
c)      Commoner in females
d)      Mandibular branch of trigeminal nerve most commonly involved
e)      Carbamazepine more efficacious than phenytoin


Q.53 Stellate ganglion block produces:-
a)      Miosis
b)      Enopthalmos
c)      Hyperhidrosis
d)      Ipsilateral nasal congestion
e)      Facial flushing

Q.54 Brachial Plexus
a)      Radial nerve formed by superior, middle and inferior trunks
b)      Cords are formed proximal to first rib
c)      Interscalene approach has lowest success rate for plamar surgery
d)      Subclavian approach most appropriate for surgery on medial arm
e)      Axillary approach best for radial nerve blockade.

Q.55 Loss of weight with a normal or increased appetite is found in:-
a)      Carcinoma of the stomach
b)      Thyrotoxicosis
c)      Diabetes mellitus
d)      Addison’s disease
e)   Prostatic Cancer

Q.56 The following are features of chronic renal failure:-
a)      Bleeding tendency
b)      Macrocytic anaemia
c)      Hypertension
d)      Splenomegaly
e)      Tetany

Q.57 Pracetamol poising may cause:-
a)      Loss of consciousness at an early stage:-
b)      Metabolic acidosis
c)      Hypoprothrombinaemia
d)      Hyperprothrombinaemia
e)      Hyperfibrinoginaemia

     Q.58 A patient is receiving intravenous antibiotic therapy for S.B.E she gradually becomes more dyspnoeic, b.p. 130/50, CVP 18 cm H₂O, diastolic and systolic murmurs are heard at the L.stemal edge. The most likely diagnosis (es) are:-

a)      Ruptured aneurysm of the ascending aorta
b)      penicillin sensitivity
c)      Cardiac failure
d)      Ruptured valve cusp
e)      Myocardial infarction

Q.59 In severe salicylate poisoning you may find:-
a)      Coma
b)      Metabolic acidosis
c)      Hypoprothrombinaemia
d)      Hyperprothrombinaemia
e)      Hyperfibrinoginaemia

Q.60 Recognized causes of persistent or recurrent painless nausea and vomiting include:-
a)      Hiatus hernia

b)      Chronic cholecystitis
c)      Hypercalcaemia
d)      Diabetes mellitus
e)      Vertebro-basilar insufficiency

Q.61 Recognised early manifestations of methanol poisoning include:-
a)      Dilated pupils
b)      Hyperventilation
c)      Respiratory alkalosis
d)      Episodes of apnoea
e)      Raised serum amylase

Q.62 Pain in the back:-
a)      Due to secondary carcinoma of the vertebrae is worst at night
b)      Due to ankylosing spondylitis is improved by rest
c)      Due to degenerative disease is accompanied by limitation of flexion and extension but not of lateral flexion
d)      Due to ankylosing spondylitis is accompanied by bilateral limitation of lateral flexion
e)      If accompanied by flattening of the lumbar lordosis is probably due to inflammatory disease.

Q.63 Myoedema may present with:-
a)      Coma
b)      Bradycardia
c)      Flat T-waves on E.C.G
d)      Carpel tunnel syndrome
e)      Macrocytic anaemia

Q.64 A 20 years old man is unconscious following a head injury. It is dangerous to :-
a)      Give homatropine eye drops to visualise the discs better
b)      Give morphine 10 mgs I.M.
c)      Do a lumbar puncture
d)      Give Mannitol 25 ml of 20% I.V.
e)      Give a G.A for reduction of his colles fracture.

Q.65 A 60 years old man is brought in by ambulance unconscious breathing O2 at 6L/min from a face mask. He is sweating; twitching his limbs and has bilateral papilloedema. His blood gases are:-
PO₂ 70 mmHg., PO₂ 70 mmHg, PH 7.16
You should:-
a)      Give phenytoin 100 mgs I.M. to prevent epileptic fits
b)      Do a lumbar puncture
c)      Arrange for an E.E.G.
d)      Give Na bicarbonate I.V to raise the arterial pH.
e)      Intubate and ventilate him

Q.66 Acute pancreatitis may cause:-
a)      Retro peritoneal abscess
b)      Pancreatic abscess
c)      Pancreatic pseudocyst
d)      Hyperglycaemia
e)      Tetany.


Q.67 In a 20 years old fit young adult with a history of vomiting for 3 weeks with no other symptoms, you would expect to find:-
a) Raised blood urea
b) Potassium 3 mEq/L
c) HCO₃↑
d) Na↑
e) Na↓

Q.68 In a patient with a vocal cord palsy due to bronchial carcinoma:
a)      It is often bilateral
b)      The R. is more often affected than th left
c)      The L. is more often affected than the right
d)      It is usually due to metastases
e)      It is usually do to radiotherapy.

Q.69 A 30 years old female patient wit increasing dyspnoea has the following results on cardiac catheterisation :-
R.A. 5, R.V. (normal), P.A. mean 50, Wedge 9, L.A. (normal), L.V. 110/8, Aorta 110/70, The diagnosis(es) are:-
a)      Mitral stenosis
b)      Mitral incompetence
c)      Idiopathic pulmonary hypertension
d)      Aortic incompetence
e)      Aortic stenosis

 Q.70 Dystrophia myotonica is characterised by:-

a)      Testicular atropy
b)      Ptosis
c)      Frontal baldness
d)      Diabetes mellitus
e)      Optic atropy.

Q.71 Post dural puncture headache
a)      Reduced incidence using paramedian approach
b)      Incidence reduced following bed rest versus early mobilization
c)      Is associated with visual and auditory disturbances
d)      Features identical of those seen in cervical myofascial pain syndrome
e)   ACTH is useful adjunct in tratment

Q.72 Nerve block at ankle
a)      Superficial peroneal never innervates first  interdigital cleft
b)      Sural nerve blocked at superior border for lateral malleolus
c)      Tibial nerve innervates sole of foot.
d)      Deep peroneal nerve blocked at medial aspect of medial malleolus
e)      Saphenous nerve is sensory extension of femoral nerve

Q.73 Balloon-tipped pulmonary artery flotation catheters.
a)      Provide direct measurement of left atrial pressure
b)      Transducer should be zeroed at level of sternal angle
c)      Pressures should be measured at end expiration
d)      P.E.E.P should be involved during P.C.W.P measurement
e)      Catheter tip should be sited in lung zone III