Test Bank for Stoelting’s Pharmacology &
Physiology in Anesthetic Practice, 6th Edition
by Pamela Flood, James P. Rathmell &
Richard D. Urman | All Chapters (1-47) | A+
Chapter 1: Basic Principles of Physiology
Question 1
A 45-year-old male under general anesthesia experiences a 20% blood loss. Mean
arterial pressure initially drops but then partially recovers within 1 minute. Which
mechanism is primarily responsible for this rapid compensation?
Answer: C
Very Deep Rationale: The baroreceptor reflex (carotid sinus and aortic arch) is
the fastest compensatory mechanism in acute hypotension. Decreased MAP
reduces baroreceptor firing, which increases sympathetic outflow, causing
tachycardia, increased contractility, and vasoconstriction. This reflex occurs within
seconds, whereas renin-angiotensin activation takes minutes and erythropoietin
takes hours to days.
Key words: Baroreceptor reflex, sympathetic activation, acute hemorrhage
compensation
Question 2
During controlled hypotension for a neurosurgical procedure, cerebral blood flow
remains constant despite a decrease in mean arterial pressure from 90 to 65 mmHg.
This phenomenon best illustrates:
Answer: B
Very Deep Rationale: Autoregulation maintains cerebral blood flow across a
MAP range of approximately 60–150 mmHg in normotensive individuals.
Myogenic and metabolic mechanisms adjust cerebral arteriolar resistance. Below
,the lower limit, flow becomes pressure-passive, increasing ischemia risk.
Key words: Autoregulation, cerebral blood flow, pressure-flow relationship
Question 3
A patient with chronic hypertension (baseline MAP 110 mmHg) is anesthetized.
The lower limit of cerebral autoregulation is most likely:
Answer: B
Very Deep Rationale: Chronic hypertension shifts the autoregulatory curve to the
right, meaning the lower limit of autoregulation is higher (e.g., 80–100 mmHg
instead of 60 mmHg). This makes hypertensive patients more vulnerable to
cerebral ischemia at what would be “normal” MAP values.
Key words: Autoregulation, chronic hypertension, rightward shift
Question 4
Which physiologic variable is maintained within the narrowest range in healthy
humans?
Answer: D
Very Deep Rationale: Arterial pH is maintained between 7.35 and 7.45. Even
small deviations (0.1 unit) significantly alter enzyme function, protein structure,
and metabolic pathways. Heart rate, blood pressure, and core temperature can vary
more widely without immediate life-threatening consequences.
Key words: Acid-base homeostasis, pH regulation
Question 5
Under general anesthesia, a patient’s core temperature falls to 35.5°C despite a
warm operating room. Which thermoregulatory mechanism is primarily impaired
by anesthetic drugs?
Answer: D
Very Deep Rationale: General anesthetics and propofol substantially raise the
threshold for shivering (i.e., shivering begins at a lower core temperature). They
also inhibit behavioral responses and reduce the vasoconstriction threshold, but the
,most clinically relevant mechanism is raising the shivering threshold, allowing
hypothermia to develop.
Key words: Thermoregulation, shivering threshold, anesthesia-induced
hypothermia
Question 6
A patient develops hemorrhagic shock. Which laboratory finding indicates a switch
to anaerobic metabolism at the cellular level before systemic acidosis becomes
evident?
Answer: C
Very Deep Rationale: The earliest cellular change in hypoxia is a drop in
mitochondrial oxygen tension. This precedes lactate accumulation and systemic
metabolic acidosis. Decreased mitochondrial PO2 reduces oxidative
phosphorylation, triggering anaerobic glycolysis and eventual lactate rise.
Key words: Hypoxia, mitochondrial oxygen tension, cellular metabolism
Question 7
A patient with septic shock requires induction of anesthesia. Hypotension
following the induction dose of propofol is more severe than expected because:
Answer: C
Very Deep Rationale: Septic shock impairs compensatory vasoconstriction due to
cytokine-mediated vasodilation, autonomic dysfunction, and downregulation of
adrenergic receptors. Propofol further reduces sympathetic tone, leading to
exaggerated hypotension. Reduced protein binding (albumin) and increased
volume of distribution play minor roles.
Key words: Septic shock, vasodilation, propofol hypotension
Question 8
A patient undergoing mechanical ventilation develops acute respiratory alkalosis
(pH 7.52, PaCO₂ 28 mmHg). The body’s immediate compensatory mechanism is:
, D. Increased erythrocyte buffering (immediate). So D is correct.
Corrected Answer: D
Very Deep Rationale: The fastest compensatory mechanism for acute respiratory
alkalosis is intracellular buffering, especially by hemoglobin in red blood cells (H+
ions dissociate from hemoglobin as pH rises). Renal compensation (bicarbonate
excretion) requires hours to days. Hyperventilation would worsen alkalosis.
Key words: Acid-base compensation, respiratory alkalosis, intracellular buffering
Question 9
During anesthesia, oxygen delivery (DO₂) decreases due to reduced cardiac output.
Which factor most strongly determines DO₂ in this scenario?
Answer: B
Very Deep Rationale: Oxygen delivery = cardiac output × arterial oxygen
content. While hemoglobin saturation and PaO₂ affect content, cardiac output has
the dominant influence because changes in flow directly affect DO₂ linearly.
Increasing PaO₂ above 100 mmHg adds little to content due to hemoglobin’s flat
dissociation curve.
Key words: Oxygen delivery, cardiac output, oxygen content
Question 10
A patient with severe aortic stenosis requires noncardiac surgery. Induction of
anesthesia with propofol causes profound hypotension. The most likely mechanism
is:
Answer: A
Very Deep Rationale: In aortic stenosis, cardiac output is fixed due to outflow
obstruction. Propofol reduces systemic vascular resistance (venodilation and
arteriolar dilation) without a compensatory increase in stroke volume. The resultant
drop in afterload causes a critical decrease in coronary perfusion pressure and
hypotension.
Key words: Aortic stenosis, propofol, hypotension, fixed cardiac output
Chapter 2: Basic Principles of Pharmacology
Physiology in Anesthetic Practice, 6th Edition
by Pamela Flood, James P. Rathmell &
Richard D. Urman | All Chapters (1-47) | A+
Chapter 1: Basic Principles of Physiology
Question 1
A 45-year-old male under general anesthesia experiences a 20% blood loss. Mean
arterial pressure initially drops but then partially recovers within 1 minute. Which
mechanism is primarily responsible for this rapid compensation?
Answer: C
Very Deep Rationale: The baroreceptor reflex (carotid sinus and aortic arch) is
the fastest compensatory mechanism in acute hypotension. Decreased MAP
reduces baroreceptor firing, which increases sympathetic outflow, causing
tachycardia, increased contractility, and vasoconstriction. This reflex occurs within
seconds, whereas renin-angiotensin activation takes minutes and erythropoietin
takes hours to days.
Key words: Baroreceptor reflex, sympathetic activation, acute hemorrhage
compensation
Question 2
During controlled hypotension for a neurosurgical procedure, cerebral blood flow
remains constant despite a decrease in mean arterial pressure from 90 to 65 mmHg.
This phenomenon best illustrates:
Answer: B
Very Deep Rationale: Autoregulation maintains cerebral blood flow across a
MAP range of approximately 60–150 mmHg in normotensive individuals.
Myogenic and metabolic mechanisms adjust cerebral arteriolar resistance. Below
,the lower limit, flow becomes pressure-passive, increasing ischemia risk.
Key words: Autoregulation, cerebral blood flow, pressure-flow relationship
Question 3
A patient with chronic hypertension (baseline MAP 110 mmHg) is anesthetized.
The lower limit of cerebral autoregulation is most likely:
Answer: B
Very Deep Rationale: Chronic hypertension shifts the autoregulatory curve to the
right, meaning the lower limit of autoregulation is higher (e.g., 80–100 mmHg
instead of 60 mmHg). This makes hypertensive patients more vulnerable to
cerebral ischemia at what would be “normal” MAP values.
Key words: Autoregulation, chronic hypertension, rightward shift
Question 4
Which physiologic variable is maintained within the narrowest range in healthy
humans?
Answer: D
Very Deep Rationale: Arterial pH is maintained between 7.35 and 7.45. Even
small deviations (0.1 unit) significantly alter enzyme function, protein structure,
and metabolic pathways. Heart rate, blood pressure, and core temperature can vary
more widely without immediate life-threatening consequences.
Key words: Acid-base homeostasis, pH regulation
Question 5
Under general anesthesia, a patient’s core temperature falls to 35.5°C despite a
warm operating room. Which thermoregulatory mechanism is primarily impaired
by anesthetic drugs?
Answer: D
Very Deep Rationale: General anesthetics and propofol substantially raise the
threshold for shivering (i.e., shivering begins at a lower core temperature). They
also inhibit behavioral responses and reduce the vasoconstriction threshold, but the
,most clinically relevant mechanism is raising the shivering threshold, allowing
hypothermia to develop.
Key words: Thermoregulation, shivering threshold, anesthesia-induced
hypothermia
Question 6
A patient develops hemorrhagic shock. Which laboratory finding indicates a switch
to anaerobic metabolism at the cellular level before systemic acidosis becomes
evident?
Answer: C
Very Deep Rationale: The earliest cellular change in hypoxia is a drop in
mitochondrial oxygen tension. This precedes lactate accumulation and systemic
metabolic acidosis. Decreased mitochondrial PO2 reduces oxidative
phosphorylation, triggering anaerobic glycolysis and eventual lactate rise.
Key words: Hypoxia, mitochondrial oxygen tension, cellular metabolism
Question 7
A patient with septic shock requires induction of anesthesia. Hypotension
following the induction dose of propofol is more severe than expected because:
Answer: C
Very Deep Rationale: Septic shock impairs compensatory vasoconstriction due to
cytokine-mediated vasodilation, autonomic dysfunction, and downregulation of
adrenergic receptors. Propofol further reduces sympathetic tone, leading to
exaggerated hypotension. Reduced protein binding (albumin) and increased
volume of distribution play minor roles.
Key words: Septic shock, vasodilation, propofol hypotension
Question 8
A patient undergoing mechanical ventilation develops acute respiratory alkalosis
(pH 7.52, PaCO₂ 28 mmHg). The body’s immediate compensatory mechanism is:
, D. Increased erythrocyte buffering (immediate). So D is correct.
Corrected Answer: D
Very Deep Rationale: The fastest compensatory mechanism for acute respiratory
alkalosis is intracellular buffering, especially by hemoglobin in red blood cells (H+
ions dissociate from hemoglobin as pH rises). Renal compensation (bicarbonate
excretion) requires hours to days. Hyperventilation would worsen alkalosis.
Key words: Acid-base compensation, respiratory alkalosis, intracellular buffering
Question 9
During anesthesia, oxygen delivery (DO₂) decreases due to reduced cardiac output.
Which factor most strongly determines DO₂ in this scenario?
Answer: B
Very Deep Rationale: Oxygen delivery = cardiac output × arterial oxygen
content. While hemoglobin saturation and PaO₂ affect content, cardiac output has
the dominant influence because changes in flow directly affect DO₂ linearly.
Increasing PaO₂ above 100 mmHg adds little to content due to hemoglobin’s flat
dissociation curve.
Key words: Oxygen delivery, cardiac output, oxygen content
Question 10
A patient with severe aortic stenosis requires noncardiac surgery. Induction of
anesthesia with propofol causes profound hypotension. The most likely mechanism
is:
Answer: A
Very Deep Rationale: In aortic stenosis, cardiac output is fixed due to outflow
obstruction. Propofol reduces systemic vascular resistance (venodilation and
arteriolar dilation) without a compensatory increase in stroke volume. The resultant
drop in afterload causes a critical decrease in coronary perfusion pressure and
hypotension.
Key words: Aortic stenosis, propofol, hypotension, fixed cardiac output
Chapter 2: Basic Principles of Pharmacology
