BARKLEY 3P EXAM ACTUAL EXAM AND
CORRECT DETAILED ANSWERS WITH
RATIONALES
1. A patient with chronic obstructive pulmonary disease (COPD) has a sustained PaCO2 of
65 mmHg. Which acid-base interpretation is most consistent with this finding, assuming no
other primary disorders?
A. Uncompensated respiratory acidosis with a serum bicarbonate of 24 mEq/L
B. Partially compensated respiratory acidosis with a serum bicarbonate of 30 mEq/L
C. Fully compensated respiratory acidosis with a serum bicarbonate of 36 mEq/L
D. Metabolic alkalosis with a serum bicarbonate of 32 mEq/L
Answer: C
Rationale: In chronic respiratory acidosis, the kidneys retain bicarbonate to compensate. For
acute, expected HCO3 increase is 1 mEq/L per 10 mmHg PaCO2 rise above 40; for chronic, it is
3-4 mEq/L per 10 mmHg rise. PaCO2 65 is 25 mmHg above normal, so chronic compensation
yields HCO3 about 40 + (4*2.5)=44? Actually, more precise: chronic expected HCO3 = 24 +
(PaCO2 * 0.4) = 24 + (25*0.4)=34, but options show 36. Option C (HCO3 36) is closest to fully
compensated, i.e., pH normalized. Option A suggests no compensation (unlikely in COPD).
Option B shows partial but HCO3 30 gives pH ~7.33 (not fully). Option D is metabolic
alkalosis, which is not primary given high PaCO2.
2. Which of the following mechanisms best explains the development of insulin resistance in
type 2 diabetes mellitus at the molecular level?
A. Reduced number of insulin receptors on target cells due to downregulation
B. Impaired insulin signaling due to serine phosphorylation of insulin receptor substrate-1 (IRS-1)
C. Increased glucagon secretion leading to hepatic glucose overproduction
D. Defective proinsulin conversion within pancreatic beta cells
Answer: B
Rationale: Insulin resistance primarily stems from post-receptor defects. Serine phosphorylation
of IRS-1 inhibits downstream PI3K/Akt signaling, reducing GLUT4 translocation. Option A
(reduced receptor number) can occur but is less dominant. Option C (glucagon excess) is a
consequence, not a primary cause. Option D describes beta-cell dysfunction, not target cell
resistance. Thus, B is the most direct molecular mechanism.
Page 1
,3. A patient receiving morphine sulfate for acute pain develops respiratory depression.
Which parameter is most sensitive for early detection of opioid-induced respiratory
depression?
A. Oxygen saturation (SpO2) below 90%
B. End-tidal CO2 (ETCO2) monitoring trend
C. Respiratory rate below 10 breaths per minute
D. Arterial blood gas pH below 7.30
Answer: B
Rationale: ETCO2 monitoring detects hypoventilation earlier than SpO2 or respiratory rate
alone, because CO2 rises before oxygen desaturation occurs. Respiratory rate can be
maintained even with shallow breaths (low tidal volume) leading to hypoventilation. ABG pH is
late sign. Hence ETCO2 trend is most sensitive.
4. In a patient with severe aortic stenosis, which compensatory mechanism is most likely to
be detected on physical examination?
A. Wide pulse pressure due to decreased systemic vascular resistance
B. A hyperdynamic left ventricular apex beat
C. A delayed and diminished carotid upstroke (pulsus parvus et tardus)
D. A prominent S3 gallop indicative of rapid ventricular filling
Answer: C
Rationale: Severe aortic stenosis obstructs left ventricular outflow, resulting in decreased stroke
volume and a slow-rising, low-amplitude carotid pulse (pulsus parvus et tardus). Pulse pressure
is narrow, not wide. The apex beat is often sustained and heaving, not hyperdynamic (seen in
volume overload). S3 gallop occurs with rapid filling in dilated cardiomyopathy, not typical in
AS. Thus, C is classic.
5. A patient on warfarin therapy for atrial fibrillation presents with an INR of 5.8 without
bleeding. The most appropriate management is:
A. Administer vitamin K 10 mg intravenously and hold warfarin until INR < 3
B. Hold warfarin for 1-2 days and recheck INR; if bleeding risk low, no reversal needed
C. Give fresh frozen plasma (FFP) 2 units and restart warfarin at lower dose
D. Administer prothrombin complex concentrate (PCC) and vitamin K 1 mg orally
Answer: B
Rationale: In the absence of bleeding, an INR of 5.8 does not require urgent reversal. Guidelines
recommend holding warfarin for several days and monitoring INR. High-dose IV vitamin K (A)
is reserved for significant bleeding but can cause overcorrection and warfarin resistance. FFP
(C) is for active bleeding. PCC (D) for life-threatening bleeding. Thus, simple holding is correct.
6. Which finding on fundoscopic examination is most indicative of hypertensive retinopathy
in a patient with a history of poorly controlled blood pressure?
Page 2
,A. Cotton-wool spots and flame-shaped hemorrhages
B. Hard exudates arranged in a star pattern at the macula
C. Microaneurysms and dot-blot hemorrhages in the periphery
D. Arteriovenous nicking and copper-wiring of retinal arterioles
Answer: D
Rationale: Chronic hypertension causes arteriosclerotic changes: arteriovenous nicking,
copper/silver wiring, and arteriolar narrowing. Cotton-wool spots and flame hemorrhages (A)
indicate malignant hypertension or other vasculopathies not exclusive. Hard exudates in star
pattern (B) are typical of hypertensive emergency but not most indicative of chronic changes.
Microaneurysms and dot-blot hemorrhages (C) are classic for diabetic retinopathy. Thus, D is
most specific for chronic hypertensive retinopathy.
7. A patient with a history of type 1 diabetes mellitus presents with nausea, vomiting, and
abdominal pain. Point-of-care glucose is 450 mg/dL, and serum ketones are positive. Which
of the following initial intravenous fluid administrations is most appropriate?
A. Lactated Ringer's solution at 500 mL/hour
B. 0.9% normal saline at 15-20 mL/kg/hour
C. 0.45% normal saline with 5% dextrose at 250 mL/hour
D. 3% hypertonic saline at 1 mL/kg/hour over 30 minutes
Answer: B
Rationale: Diabetic ketoacidosis requires aggressive isotonic fluid resuscitation to correct
hypovolemia. 0.9% normal saline at 15-20 mL/kg/hour is standard. Lactated Ringer's (A) is not
recommended due to the lactate load. Hypotonic fluids (C) are avoided initially due to risk of
cerebral edema. Hypertonic saline (D) is for severe hyponatremia. Thus, B is correct.
8. A patient with community-acquired pneumonia is started on levofloxacin. Which
mechanism of action best describes the effect of fluoroquinolones on bacterial replication?
A. Inhibition of cell wall synthesis by blocking transpeptidase enzymes
B. Binding to the 50S ribosomal subunit, preventing peptide bond formation
C. Inhibition of DNA gyrase and topoisomerase IV, disrupting DNA supercoiling
D. Interference with folic acid synthesis by competing with para-aminobenzoic acid
Answer: C
Rationale: Fluoroquinolones target bacterial type II topoisomerases: DNA gyrase
(topoisomerase II) and topoisomerase IV, preventing DNA replication. Option A describes
beta-lactams. Option B describes macrolides and chloramphenicol. Option D describes
sulfonamides. Thus, C is correct.
9. Which of the following findings on cardiac auscultation is most consistent with a
diagnosis of mitral valve prolapse?
A. A mid-systolic click followed by a late systolic murmur at the apex
Page 3
, B. An opening snap followed by a low-pitched mid-diastolic rumble
C. A holosystolic blowing murmur radiating to the axilla
D. A systolic ejection murmur at the right upper sternal border with radiation to carotids
Answer: A
Rationale: Mitral valve prolapse produces a mid-systolic click (from sudden tightening of
chordae) and often a late systolic murmur (from mitral regurgitation). Opening snap and
diastolic rumble (B) indicate mitral stenosis. Holosystolic murmur radiating to axilla (C) is
typical of mitral regurgitation from other causes (e.g., rheumatic). Ejection murmur at right
upper sternal border (D) is aortic stenosis. Thus, A is pathognomonic.
10. A patient with acute kidney injury (AKI) has oliguria, urine osmolality 350 mOsm/kg,
urine sodium 15 mEq/L, and BUN:Cr ratio 25:1. Which etiology is most likely?
A. Acute tubular necrosis (ATN)
B. Prerenal azotemia due to volume depletion
C. Postrenal obstruction from prostatic hyperplasia
D. Acute glomerulonephritis secondary to IgA nephropathy
Answer: B
Rationale: Prerenal AKI typically presents with low urine sodium (<20 mEq/L), high urine
osmolality (>500 mEq/L? Actually high urine osmolality >500), and elevated BUN:Cr ratio
(>20:1). Here, urine sodium 15 (low) and BUN:Cr 25:1 support prerenal. Urine osmolality 350
is moderately high but not extremely high; still consistent. ATN (A) would show high urine
sodium >40, low osmolality. Postrenal (C) and glomerulonephritis (D) often have more variable
findings. Thus, B is most likely.
11. A patient on warfarin for atrial fibrillation is prescribed a course of ciprofloxacin for a
urinary tract infection. Which effect on the international normalized ratio (INR) is most
expected?
A. Decrease due to increased warfarin metabolism
B. Increase due to displacement of warfarin from protein binding
C. No change because the interaction is negligible
D. Increase due to inhibition of warfarin metabolism
Answer: D
Rationale: Ciprofloxacin inhibits hepatic cytochrome P450 enzymes, particularly CYP1A2 and
CYP3A4, which metabolize warfarin. This leads to elevated warfarin levels and increased INR,
raising bleeding risk. Option B is incorrect because fluoroquinolones do not significantly
displace warfarin from albumin; the primary mechanism is metabolic inhibition.
12. In a patient with chronic heart failure, which compensatory mechanism initially
maintains cardiac output but ultimately contributes to ventricular remodeling and
progression of disease?
Page 4
CORRECT DETAILED ANSWERS WITH
RATIONALES
1. A patient with chronic obstructive pulmonary disease (COPD) has a sustained PaCO2 of
65 mmHg. Which acid-base interpretation is most consistent with this finding, assuming no
other primary disorders?
A. Uncompensated respiratory acidosis with a serum bicarbonate of 24 mEq/L
B. Partially compensated respiratory acidosis with a serum bicarbonate of 30 mEq/L
C. Fully compensated respiratory acidosis with a serum bicarbonate of 36 mEq/L
D. Metabolic alkalosis with a serum bicarbonate of 32 mEq/L
Answer: C
Rationale: In chronic respiratory acidosis, the kidneys retain bicarbonate to compensate. For
acute, expected HCO3 increase is 1 mEq/L per 10 mmHg PaCO2 rise above 40; for chronic, it is
3-4 mEq/L per 10 mmHg rise. PaCO2 65 is 25 mmHg above normal, so chronic compensation
yields HCO3 about 40 + (4*2.5)=44? Actually, more precise: chronic expected HCO3 = 24 +
(PaCO2 * 0.4) = 24 + (25*0.4)=34, but options show 36. Option C (HCO3 36) is closest to fully
compensated, i.e., pH normalized. Option A suggests no compensation (unlikely in COPD).
Option B shows partial but HCO3 30 gives pH ~7.33 (not fully). Option D is metabolic
alkalosis, which is not primary given high PaCO2.
2. Which of the following mechanisms best explains the development of insulin resistance in
type 2 diabetes mellitus at the molecular level?
A. Reduced number of insulin receptors on target cells due to downregulation
B. Impaired insulin signaling due to serine phosphorylation of insulin receptor substrate-1 (IRS-1)
C. Increased glucagon secretion leading to hepatic glucose overproduction
D. Defective proinsulin conversion within pancreatic beta cells
Answer: B
Rationale: Insulin resistance primarily stems from post-receptor defects. Serine phosphorylation
of IRS-1 inhibits downstream PI3K/Akt signaling, reducing GLUT4 translocation. Option A
(reduced receptor number) can occur but is less dominant. Option C (glucagon excess) is a
consequence, not a primary cause. Option D describes beta-cell dysfunction, not target cell
resistance. Thus, B is the most direct molecular mechanism.
Page 1
,3. A patient receiving morphine sulfate for acute pain develops respiratory depression.
Which parameter is most sensitive for early detection of opioid-induced respiratory
depression?
A. Oxygen saturation (SpO2) below 90%
B. End-tidal CO2 (ETCO2) monitoring trend
C. Respiratory rate below 10 breaths per minute
D. Arterial blood gas pH below 7.30
Answer: B
Rationale: ETCO2 monitoring detects hypoventilation earlier than SpO2 or respiratory rate
alone, because CO2 rises before oxygen desaturation occurs. Respiratory rate can be
maintained even with shallow breaths (low tidal volume) leading to hypoventilation. ABG pH is
late sign. Hence ETCO2 trend is most sensitive.
4. In a patient with severe aortic stenosis, which compensatory mechanism is most likely to
be detected on physical examination?
A. Wide pulse pressure due to decreased systemic vascular resistance
B. A hyperdynamic left ventricular apex beat
C. A delayed and diminished carotid upstroke (pulsus parvus et tardus)
D. A prominent S3 gallop indicative of rapid ventricular filling
Answer: C
Rationale: Severe aortic stenosis obstructs left ventricular outflow, resulting in decreased stroke
volume and a slow-rising, low-amplitude carotid pulse (pulsus parvus et tardus). Pulse pressure
is narrow, not wide. The apex beat is often sustained and heaving, not hyperdynamic (seen in
volume overload). S3 gallop occurs with rapid filling in dilated cardiomyopathy, not typical in
AS. Thus, C is classic.
5. A patient on warfarin therapy for atrial fibrillation presents with an INR of 5.8 without
bleeding. The most appropriate management is:
A. Administer vitamin K 10 mg intravenously and hold warfarin until INR < 3
B. Hold warfarin for 1-2 days and recheck INR; if bleeding risk low, no reversal needed
C. Give fresh frozen plasma (FFP) 2 units and restart warfarin at lower dose
D. Administer prothrombin complex concentrate (PCC) and vitamin K 1 mg orally
Answer: B
Rationale: In the absence of bleeding, an INR of 5.8 does not require urgent reversal. Guidelines
recommend holding warfarin for several days and monitoring INR. High-dose IV vitamin K (A)
is reserved for significant bleeding but can cause overcorrection and warfarin resistance. FFP
(C) is for active bleeding. PCC (D) for life-threatening bleeding. Thus, simple holding is correct.
6. Which finding on fundoscopic examination is most indicative of hypertensive retinopathy
in a patient with a history of poorly controlled blood pressure?
Page 2
,A. Cotton-wool spots and flame-shaped hemorrhages
B. Hard exudates arranged in a star pattern at the macula
C. Microaneurysms and dot-blot hemorrhages in the periphery
D. Arteriovenous nicking and copper-wiring of retinal arterioles
Answer: D
Rationale: Chronic hypertension causes arteriosclerotic changes: arteriovenous nicking,
copper/silver wiring, and arteriolar narrowing. Cotton-wool spots and flame hemorrhages (A)
indicate malignant hypertension or other vasculopathies not exclusive. Hard exudates in star
pattern (B) are typical of hypertensive emergency but not most indicative of chronic changes.
Microaneurysms and dot-blot hemorrhages (C) are classic for diabetic retinopathy. Thus, D is
most specific for chronic hypertensive retinopathy.
7. A patient with a history of type 1 diabetes mellitus presents with nausea, vomiting, and
abdominal pain. Point-of-care glucose is 450 mg/dL, and serum ketones are positive. Which
of the following initial intravenous fluid administrations is most appropriate?
A. Lactated Ringer's solution at 500 mL/hour
B. 0.9% normal saline at 15-20 mL/kg/hour
C. 0.45% normal saline with 5% dextrose at 250 mL/hour
D. 3% hypertonic saline at 1 mL/kg/hour over 30 minutes
Answer: B
Rationale: Diabetic ketoacidosis requires aggressive isotonic fluid resuscitation to correct
hypovolemia. 0.9% normal saline at 15-20 mL/kg/hour is standard. Lactated Ringer's (A) is not
recommended due to the lactate load. Hypotonic fluids (C) are avoided initially due to risk of
cerebral edema. Hypertonic saline (D) is for severe hyponatremia. Thus, B is correct.
8. A patient with community-acquired pneumonia is started on levofloxacin. Which
mechanism of action best describes the effect of fluoroquinolones on bacterial replication?
A. Inhibition of cell wall synthesis by blocking transpeptidase enzymes
B. Binding to the 50S ribosomal subunit, preventing peptide bond formation
C. Inhibition of DNA gyrase and topoisomerase IV, disrupting DNA supercoiling
D. Interference with folic acid synthesis by competing with para-aminobenzoic acid
Answer: C
Rationale: Fluoroquinolones target bacterial type II topoisomerases: DNA gyrase
(topoisomerase II) and topoisomerase IV, preventing DNA replication. Option A describes
beta-lactams. Option B describes macrolides and chloramphenicol. Option D describes
sulfonamides. Thus, C is correct.
9. Which of the following findings on cardiac auscultation is most consistent with a
diagnosis of mitral valve prolapse?
A. A mid-systolic click followed by a late systolic murmur at the apex
Page 3
, B. An opening snap followed by a low-pitched mid-diastolic rumble
C. A holosystolic blowing murmur radiating to the axilla
D. A systolic ejection murmur at the right upper sternal border with radiation to carotids
Answer: A
Rationale: Mitral valve prolapse produces a mid-systolic click (from sudden tightening of
chordae) and often a late systolic murmur (from mitral regurgitation). Opening snap and
diastolic rumble (B) indicate mitral stenosis. Holosystolic murmur radiating to axilla (C) is
typical of mitral regurgitation from other causes (e.g., rheumatic). Ejection murmur at right
upper sternal border (D) is aortic stenosis. Thus, A is pathognomonic.
10. A patient with acute kidney injury (AKI) has oliguria, urine osmolality 350 mOsm/kg,
urine sodium 15 mEq/L, and BUN:Cr ratio 25:1. Which etiology is most likely?
A. Acute tubular necrosis (ATN)
B. Prerenal azotemia due to volume depletion
C. Postrenal obstruction from prostatic hyperplasia
D. Acute glomerulonephritis secondary to IgA nephropathy
Answer: B
Rationale: Prerenal AKI typically presents with low urine sodium (<20 mEq/L), high urine
osmolality (>500 mEq/L? Actually high urine osmolality >500), and elevated BUN:Cr ratio
(>20:1). Here, urine sodium 15 (low) and BUN:Cr 25:1 support prerenal. Urine osmolality 350
is moderately high but not extremely high; still consistent. ATN (A) would show high urine
sodium >40, low osmolality. Postrenal (C) and glomerulonephritis (D) often have more variable
findings. Thus, B is most likely.
11. A patient on warfarin for atrial fibrillation is prescribed a course of ciprofloxacin for a
urinary tract infection. Which effect on the international normalized ratio (INR) is most
expected?
A. Decrease due to increased warfarin metabolism
B. Increase due to displacement of warfarin from protein binding
C. No change because the interaction is negligible
D. Increase due to inhibition of warfarin metabolism
Answer: D
Rationale: Ciprofloxacin inhibits hepatic cytochrome P450 enzymes, particularly CYP1A2 and
CYP3A4, which metabolize warfarin. This leads to elevated warfarin levels and increased INR,
raising bleeding risk. Option B is incorrect because fluoroquinolones do not significantly
displace warfarin from albumin; the primary mechanism is metabolic inhibition.
12. In a patient with chronic heart failure, which compensatory mechanism initially
maintains cardiac output but ultimately contributes to ventricular remodeling and
progression of disease?
Page 4
