Crystalloid vs. colloid solutions — MCQs

10 questions

A 28-year-old research assistant is brought to the emergency department for severe chemical burns 30 minutes after accidentally spilling hydrochloric acid on himself. The burns cover both hands and forearms. His temperature is 37°C (98.6°F), pulse is 112/min, respirations are 20/min, and blood pressure is 108/82 mm Hg. Initial stabilization and resuscitation is begun, including respiratory support, fluid resuscitation, and cardiovascular stabilization. The burned skin is irrigated with saline water to remove the chemical agent. Which of the following is the most appropriate method to verify adequate fluid infusion in this patient?

A 7-year-old boy is brought to the emergency room because of severe, acute diarrhea. He is drowsy with a dull, lethargic appearance. He has sunken eyes, poor skin turgor, and dry oral mucous membranes and tongue. He has a rapid, thready pulse with a systolic blood pressure of 60 mm Hg and his respirations are 33/min. His capillary refill time is 6 sec. He has had no urine output for the past 24 hours. Which of the following is the most appropriate next step in treatment?

A 70-year-old man with a long-standing history of diabetes mellitus type 2 and hypertension presents with complaints of constant wrist and shoulder pain. Currently, the patient undergoes hemodialysis 2 to 3 times a week and is on the transplant list for a kidney. The patient denies any recent traumas. Which of the following proteins is likely to be increased in his plasma, causing the patient’s late complaints?

A scientist is studying the excretion of a novel toxin X by the kidney in order to understand the dynamics of this new substance. He discovers that this new toxin X has a clearance that is half that of inulin in a particular patient. This patient's filtration fraction is 20% and his para-aminohippuric acid (PAH) dynamics are as follows: Urine volume: 100 mL/min Urine PAH concentration: 30 mg/mL Plasma PAH concentration: 5 mg/mL Given these findings, what is the clearance of the novel toxin X?

A 35-year-old man is brought to the emergency department from a kitchen fire. The patient was cooking when boiling oil splashed on his exposed skin. His temperature is 99.7°F (37.6°C), blood pressure is 127/82 mmHg, pulse is 120/min, respirations are 12/min, and oxygen saturation is 98% on room air. He has dry, nontender, and circumferential burns over his arms bilaterally, burns over the anterior portion of his chest and abdomen, and tender spot burns with blisters on his shins. A 1L bolus of normal saline is administered and the patient is given morphine and his pulse is subsequently 80/min. A Foley catheter is placed which drains 10 mL of urine. What is the best next step in management?

A 29-year-old man is brought to the emergency room 6 hours after the onset of severe epigastric pain and vomiting. His heart rate is 110/min and blood pressure is 98/72 mm Hg. He is diagnosed with acute pancreatitis, and fluid resuscitation with normal saline is initiated. Which of the following is the most likely immediate effect of fluid resuscitation in this patient?

A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?

A 24-year-old woman is brought to the emergency department after being assaulted. The paramedics report that the patient was found conscious and reported being kicked many times in the torso. She is alert and able to respond to questions. She denies any head trauma. She has a past medical history of endometriosis and a tubo-ovarian abscess that was removed surgically two years ago. Her only home medication is oral contraceptive pills. Her temperature is 98.5°F (36.9°C), blood pressure is 82/51 mmHg, pulse is 136/min, respirations are 24/min, and SpO2 is 94%. She has superficial lacerations to the face and severe bruising over her chest and abdomen. Her lungs are clear to auscultation bilaterally and her abdomen is soft, distended, and diffusely tender to palpation. Her skin is cool and clammy. Her FAST exam reveals fluid in the perisplenic space. Which of the following is the next best step in management?

Three hours after undergoing open proctocolectomy for ulcerative colitis, a 42-year-old male complains of abdominal pain. The pain is localized to the periumbilical and hypogastric regions. A total of 20 mL of urine has drained from his urinary catheter since the end of the procedure. Temperature is 37.2°C (98.9°F), pulse is 92/min, respirations are 12/min, and blood pressure is 110/72 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 99%. Physical examination shows a 20 cm vertical midline incision and an ileostomy in the right lower quadrant. There is no fluid drainage from the surgical wounds. The urinary catheter flushes easily and is without obstruction. Cardiopulmonary examination shows no abnormalities. Serum studies show a blood urea nitrogen of 30 mg/dL and a creatinine of 1.3 mg/dL. Which of the following is the most appropriate next step in management?

Q10

A 45-year-old man is brought to the emergency department following a house fire. Following initial stabilization, the patient is transferred to the ICU for management of his third-degree burn injuries. On the second day of hospitalization, a routine laboratory panel is obtained, and the results are demonstrated below. Per the nurse, he remains stable compared to the day prior. His temperature is 99°F (37°C), blood pressure is 92/64 mmHg, pulse is 98/min, respirations are 14/min, and SpO2 is 98%. A physical examination demonstrates an unresponsive patient with extensive burn injuries throughout his torso and lower extremities. Hemoglobin: 13 g/dL Hematocrit: 36% Leukocyte count: 10,670/mm^3 with normal differential Platelet count: 180,000/mm^3 Serum: Na+: 135 mEq/L Cl-: 98 mEq/L K+: 4.7 mEq/L HCO3-: 25 mEq/L BUN: 10 mg/dL Glucose: 123 mg/dL Creatinine: 1.8 mg/dL Thyroid-stimulating hormone: 4.3 µU/mL Triiodothyronine: 48 ng/dL Thyroxine: 10 ug/dL Ca2+: 8.7 mg/dL AST: 89 U/L ALT: 135 U/L What is the best course of management for this patient?

Crystalloid vs. colloid solutions US Medical PG Practice Questions and MCQs

Question 1: A 28-year-old research assistant is brought to the emergency department for severe chemical burns 30 minutes after accidentally spilling hydrochloric acid on himself. The burns cover both hands and forearms. His temperature is 37°C (98.6°F), pulse is 112/min, respirations are 20/min, and blood pressure is 108/82 mm Hg. Initial stabilization and resuscitation is begun, including respiratory support, fluid resuscitation, and cardiovascular stabilization. The burned skin is irrigated with saline water to remove the chemical agent. Which of the following is the most appropriate method to verify adequate fluid infusion in this patient?

A. The Parkland formula
B. Blood pressure
C. Pulmonary capillary wedge pressure
D. Heart rate
E. Urinary output (Correct Answer)

Explanation: ***Urinary output*** - Maintaining a specific **urinary output** (e.g., adult with major burns: 0.5-1.0 mL/kg/hr or 30-50 mL/hr) is the most reliable clinical indicator of adequate fluid resuscitation in burn patients. - This ensures sufficient end-organ perfusion and avoids both under-resuscitation (leading to shock and organ damage) and over-resuscitation (risk of compartment syndrome and pulmonary edema). *The Parkland formula* - The **Parkland formula** is used to *calculate* the initial fluid volume needed, but it does not *verify* the adequacy of the infusion once started. - This formula provides a starting point for fluid administration, which then needs to be adjusted based on the patient's response. *Blood pressure* - **Blood pressure** can be misleading in burn patients; it may remain deceptively normal due to compensatory mechanisms even with significant fluid deficits. - It is a late indicator of hypovolemic shock, and relying solely on it can lead to under-resuscitation. *Pulmonary capillary wedge pressure* - **Pulmonary capillary wedge pressure (PCWP)** requires invasive monitoring via a pulmonary artery catheter, which is rarely indicated for routine fluid management in burn patients due to its invasiveness and associated risks. - Less invasive and equally effective methods, like urinary output, are preferred for monitoring resuscitation. *Heart rate* - **Heart rate** is a sensitive but non-specific indicator of fluid status; it can be elevated due to pain, anxiety, or infection, not solely hypovolemia. - While a decreasing heart rate can indicate improved fluid status, it is not as reliable or direct an indicator of end-organ perfusion as urinary output.

Question 2: A 7-year-old boy is brought to the emergency room because of severe, acute diarrhea. He is drowsy with a dull, lethargic appearance. He has sunken eyes, poor skin turgor, and dry oral mucous membranes and tongue. He has a rapid, thready pulse with a systolic blood pressure of 60 mm Hg and his respirations are 33/min. His capillary refill time is 6 sec. He has had no urine output for the past 24 hours. Which of the following is the most appropriate next step in treatment?

A. Start IV fluid resuscitation by administering colloid solutions
B. Provide oral rehydration therapy to correct dehydration
C. Give initial IV bolus of 2 L of Ringer’s lactate, followed by packed red cells, fresh frozen plasma, and platelets in a ratio of 1:1:1
D. Start IV fluid resuscitation with normal saline or Ringer’s lactate, along with monitoring of vitals and urine output (Correct Answer)
E. Give antidiarrheal drugs

Explanation: ***Start IV fluid resuscitation with normal saline or Ringer's lactate, along with monitoring of vitals and urine output*** - This patient presents with **severe dehydration** and **hypovolemic shock** (lethargy, sunken eyes, poor skin turgor, dry mucous membranes, rapid thready pulse, hypotension [systolic BP 60 mmHg], tachypnea, prolonged capillary refill >5 seconds, and anuria). - According to **PALS guidelines**, the immediate priority is rapid intravenous administration of **isotonic crystalloids** (normal saline or Ringer's lactate) given as **20 mL/kg boluses** over 5-20 minutes, repeated as needed based on clinical response. - Close monitoring of vital signs, mental status, perfusion (capillary refill), and urine output is essential to assess response to resuscitation and guide further fluid management. *Start IV fluid resuscitation by administering colloid solutions* - While colloids (albumin, synthetic colloids) can expand intravascular volume, **isotonic crystalloids** are preferred for initial resuscitation in severe dehydration per **WHO and PALS guidelines**. - Crystalloids are equally effective, more readily available, less expensive, and have fewer potential adverse effects compared to colloids in pediatric dehydration. - There is no proven survival benefit of colloids over crystalloids in this clinical scenario. *Provide oral rehydration therapy to correct dehydration* - **Oral rehydration therapy (ORT)** is the appropriate first-line treatment for **mild to moderate dehydration** in children who can tolerate oral intake. - However, ORT is **contraindicated** in patients with **severe dehydration** or **hypovolemic shock**, particularly those with altered mental status, inability to drink, or hemodynamic instability. - This patient's drowsiness, hypotension, and signs of shock require immediate IV resuscitation; ORT would be too slow and potentially dangerous. *Give initial IV bolus of 2 L of Ringer's lactate, followed by packed red cells, fresh frozen plasma, and platelets in a ratio of 1:1:1* - A 2-liter bolus is **excessive and dangerous** for a 7-year-old child (average weight ~23 kg); the appropriate initial bolus is **20 mL/kg** (~460 mL), which can be repeated based on response. - The **1:1:1 massive transfusion protocol** (packed RBCs, FFP, platelets) is indicated for **hemorrhagic shock** with significant blood loss, not for hypovolemic shock from dehydration. - There is no evidence of bleeding or coagulopathy in this patient; blood products are not indicated. *Give antidiarrheal drugs* - **Antidiarrheal agents** (loperamide, diphenoxylate) are **contraindicated** in young children with acute infectious diarrhea, as they can prolong illness, increase risk of complications (toxic megacolon, bacterial overgrowth), and mask serious underlying conditions. - The priority in severe dehydration is **fluid and electrolyte resuscitation**, not stopping the diarrhea. - The diarrhea typically resolves once the underlying infection is controlled and hydration is restored.

Question 3: A 70-year-old man with a long-standing history of diabetes mellitus type 2 and hypertension presents with complaints of constant wrist and shoulder pain. Currently, the patient undergoes hemodialysis 2 to 3 times a week and is on the transplant list for a kidney. The patient denies any recent traumas. Which of the following proteins is likely to be increased in his plasma, causing the patient’s late complaints?

A. Amyloid precursor protein
B. Amyloid A (AA)
C. β2-microglobulin (Correct Answer)
D. Transthyretin (TTR)
E. Ig light chains

Explanation: **β2-microglobulin** - The patient's presentation with **chronic wrist and shoulder pain**, particularly in the setting of **long-term hemodialysis for end-stage renal disease (ESRD)**, is highly suggestive of **dialysis-related amyloidosis (DRA)**. - **β2-microglobulin** is a small protein that is normally filtered by the kidneys. In ESRD patients on hemodialysis, it accumulates and forms amyloid deposits, primarily in joint capsules, synovium, and bones. *Amyloid precursor protein* - **Amyloid precursor protein (APP)** is primarily associated with **Alzheimer's disease**, where its proteolytic cleavage leads to the formation of amyloid-beta plaques in the brain. - It is not directly implicated in joint pain or musculoskeletal amyloidosis in the context of renal failure. *Amyloid A (AA)* - **Amyloid A (AA)** is the protein responsible for **secondary (reactive) amyloidosis**, which is typically associated with chronic inflammatory conditions like rheumatoid arthritis or chronic infections. - While the patient has some chronic conditions (diabetes, hypertension), his joint pain is more characteristic of dialysis-related amyloidosis, not systemic inflammation-induced AA amyloidosis. *Transthyretin (TTR)* - **Transthyretin (TTR)** is associated with **familial amyloid polyneuropathy** and **senile systemic amyloidosis (SSA)**, causing heart failure or carpal tunnel syndrome, but it is not directly linked to dialysis-related amyloidosis. - The patient's symptoms are more indicative of the specific type of amyloidosis seen in ESRD. *Ig light chains* - **Immunoglobulin (Ig) light chains** are involved in **primary (AL) amyloidosis**, which is caused by a plasma cell dyscrasia. - While AL amyloidosis can affect various organs, including joints, the patient's history of ESRD and hemodialysis makes **β2-microglobulin amyloidosis** the most specific and likely cause of his musculoskeletal symptoms.

Question 4: A scientist is studying the excretion of a novel toxin X by the kidney in order to understand the dynamics of this new substance. He discovers that this new toxin X has a clearance that is half that of inulin in a particular patient. This patient's filtration fraction is 20% and his para-aminohippuric acid (PAH) dynamics are as follows: Urine volume: 100 mL/min Urine PAH concentration: 30 mg/mL Plasma PAH concentration: 5 mg/mL Given these findings, what is the clearance of the novel toxin X?

A. 1,500 mL/min
B. 600 mL/min
C. 300 mL/min
D. 60 mL/min (Correct Answer)
E. 120 mL/min

Explanation: ***60 ml/min*** - First, calculate the **renal plasma flow (RPF)** using PAH clearance: RPF = (Urine PAH conc. × Urine vol.) / Plasma PAH conc. = (30 mg/mL × 100 mL/min) / 5 mg/mL = 600 mL/min. - Next, calculate the **glomerular filtration rate (GFR)**, which is the clearance of inulin. GFR = RPF × Filtration Fraction = 600 mL/min × 0.20 = 120 mL/min. Toxin X clearance is half of inulin clearance, so 120 mL/min / 2 = **60 mL/min**. *1,500 ml/min* - This value is likely obtained if an incorrect formula or conversion was made, possibly by misinterpreting the units or the relationship between GFR, RPF, and filtration fraction. - It significantly overestimates the clearance for a substance that is cleared at half the rate of inulin. *600 ml/min* - This value represents the **renal plasma flow (RPF)**, calculated using the PAH clearance data. - It does not account for the filtration fraction or the fact that toxin X clearance is half of inulin clearance (GFR). *300 ml/min* - This value would be obtained if the renal plasma flow (RPF) was incorrectly halved, or if an intermediate calculation was misinterpreted as the final answer. - It does not align with the given filtration fraction and the relationship between toxin X and inulin clearance. *120 ml/min* - This value represents the **glomerular filtration rate (GFR)**, which is equal to the clearance of inulin (RPF × Filtration Fraction = 600 mL/min × 0.20 = 120 mL/min). - The question states that the clearance of toxin X is **half** that of inulin, so this is an intermediate step, not the final answer.

Question 5: A 35-year-old man is brought to the emergency department from a kitchen fire. The patient was cooking when boiling oil splashed on his exposed skin. His temperature is 99.7°F (37.6°C), blood pressure is 127/82 mmHg, pulse is 120/min, respirations are 12/min, and oxygen saturation is 98% on room air. He has dry, nontender, and circumferential burns over his arms bilaterally, burns over the anterior portion of his chest and abdomen, and tender spot burns with blisters on his shins. A 1L bolus of normal saline is administered and the patient is given morphine and his pulse is subsequently 80/min. A Foley catheter is placed which drains 10 mL of urine. What is the best next step in management?

A. Additional fluids and escharotomy (Correct Answer)
B. Escharotomy
C. Continuous observation
D. Moist dressings and discharge
E. Additional fluids and admission to the ICU

Explanation: ***Additional fluids and escharotomy*** - The patient has **circumferential full-thickness burns** on both arms (dry, nontender), which require **escharotomy** to prevent compartment syndrome and vascular compromise to the limbs. - The **oliguria** (10 mL urine output) despite a 1L fluid bolus indicates **inadequate fluid resuscitation** from burn shock. With approximately 40% TBSA burns, the patient requires aggressive fluid resuscitation per the Parkland formula (4 mL/kg/% TBSA), which would be approximately 11 liters in the first 24 hours. Adequate resuscitation targets urine output of 0.5-1 mL/kg/hr (35-70 mL/hr for this patient). - Both interventions are immediately necessary: fluids for burn shock and escharotomy for circumferential burns. *Escharotomy* - While **escharotomy** is essential for the circumferential full-thickness burns to prevent compartment syndrome, it alone will not address the **severe fluid deficit** causing oliguria and hypoperfusion. - The low urine output reflects systemic hypovolemia from burn shock, not just local compartment issues, requiring aggressive fluid resuscitation. *Continuous observation* - **Continuous observation** is inappropriate given the patient's critical findings: circumferential full-thickness burns requiring urgent escharotomy and oliguria indicating inadequate resuscitation. - Delaying escharotomy can lead to irreversible ischemic damage to the limbs, and inadequate fluid resuscitation can progress to multiorgan failure. *Moist dressings and discharge* - This option is completely inappropriate for a patient with **extensive deep burns** (approximately 40% TBSA) including full-thickness injuries requiring hospitalization and specialized burn care. - Discharge would lead to severe complications including infection, inadequate fluid resuscitation, compartment syndrome, and potential limb loss. *Additional fluids and admission to the ICU* - While ICU admission and additional fluids are necessary components of care, this option is **incomplete** because it omits **escharotomy**, which is urgently needed for the circumferential full-thickness burns. - Escharotomy is a time-sensitive procedure that must be performed promptly to prevent ischemic injury to the limbs from vascular compromise.

Question 6: A 29-year-old man is brought to the emergency room 6 hours after the onset of severe epigastric pain and vomiting. His heart rate is 110/min and blood pressure is 98/72 mm Hg. He is diagnosed with acute pancreatitis, and fluid resuscitation with normal saline is initiated. Which of the following is the most likely immediate effect of fluid resuscitation in this patient?

A. Increase in plasma oncotic pressure
B. Increase in glomerular filtration fraction
C. Increase in volume of distribution
D. Increase in cardiac afterload
E. Increase in myocardial oxygen demand (Correct Answer)

Explanation: ***Increase in myocardial oxygen demand*** - Fluid resuscitation in a hypotensive patient with tachycardia increases **cardiac preload** and **stroke volume**, leading to higher cardiac output. - This increased workload on the heart, especially when the patient is already tachycardic, directly translates to an **increased demand for oxygen** by the myocardium. *Increase in plasma oncotic pressure* - Fluid resuscitation with **normal saline** (crystalloid solution) primarily increases intravascular volume but does not significantly increase plasma proteins, which are responsible for oncotic pressure. - In fact, large volumes of crystalloids can sometimes **slightly decrease oncotic pressure** due to hemodilution. *Increase in glomerular filtration fraction* - Fluid resuscitation improves **renal perfusion** and **glomerular filtration rate (GFR)** by restoring blood pressure and intravascular volume. - However, the glomerular filtration fraction, which is the ratio of GFR to renal plasma flow, does not necessarily increase; it might even decrease as renal plasma flow improves. *Increase in volume of distribution* - Volume of distribution refers to the apparent volume into which a drug distributes in the body. Fluid resuscitation **increases the intravascular fluid volume**, which is part of the total body water, but this is a change in actual volume, not a change in a pharmacokinetic parameter for drug distribution. - It would more accurately be described as increasing the **effective circulating volume**, not the **volume of distribution** in a pharmacological sense. *Increase in cardiac afterload* - Cardiac afterload refers to the resistance the heart must overcome to eject blood. While fluid resuscitation increases **intravascular volume**, it primarily affects **preload**. - Although indirectly, by improving cardiac output and maintaining blood pressure, there might be a slight increase in afterload, an **increase in myocardial oxygen demand** is a more direct and immediate consequence of the increased workload.

Question 7: A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?

A. "Does the diarrhea typically precede the constipation, or vice-versa?"
B. "Is the diarrhea foul-smelling?"
C. "Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life"
D. "Are the symptoms worse in the morning or at night?"
E. "Can you tell me more about the symptoms you have been experiencing?" (Correct Answer)

Explanation: ***Can you tell me more about the symptoms you have been experiencing?*** - This **open-ended question** encourages the patient to provide a **comprehensive narrative** of their symptoms, including details about onset, frequency, duration, alleviating/aggravating factors, and associated symptoms, which is crucial for diagnosis. - In a patient presenting with vague, intermittent symptoms like alternating constipation and diarrhea, allowing them to elaborate freely can reveal important clues that might not be captured by more targeted questions. *Does the diarrhea typically precede the constipation, or vice-versa?* - While knowing the sequence of symptoms can be helpful in understanding the **pattern of bowel dysfunction**, it is a very specific question that might overlook other important aspects of the patient's experience. - It prematurely narrows the focus without first obtaining a broad understanding of the patient's overall symptomatic picture. *Is the diarrhea foul-smelling?* - Foul-smelling diarrhea can indicate **malabsorption** or **bacterial overgrowth**, which are important to consider in some gastrointestinal conditions. - However, this is a **specific symptom inquiry** that should follow a more general exploration of the patient's symptoms, as it may not be relevant if other crucial details are missed. *Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life* - Quantifying pain intensity is useful for assessing the **severity of discomfort** and monitoring changes over time. - However, for a patient with intermittent rather than acute, severe pain, understanding the **character, location, and triggers** of the pain is often more diagnostically valuable than just a numerical rating initially. *Are the symptoms worse in the morning or at night?* - Diurnal variation can be relevant in certain conditions, such as inflammatory bowel diseases where nocturnal symptoms might be more concerning, or functional disorders whose symptoms might be stress-related. - This is another **specific question** that should come after gathering a more complete initial picture of the patient's symptoms to ensure no key information is overlooked.

Question 8: A 24-year-old woman is brought to the emergency department after being assaulted. The paramedics report that the patient was found conscious and reported being kicked many times in the torso. She is alert and able to respond to questions. She denies any head trauma. She has a past medical history of endometriosis and a tubo-ovarian abscess that was removed surgically two years ago. Her only home medication is oral contraceptive pills. Her temperature is 98.5°F (36.9°C), blood pressure is 82/51 mmHg, pulse is 136/min, respirations are 24/min, and SpO2 is 94%. She has superficial lacerations to the face and severe bruising over her chest and abdomen. Her lungs are clear to auscultation bilaterally and her abdomen is soft, distended, and diffusely tender to palpation. Her skin is cool and clammy. Her FAST exam reveals fluid in the perisplenic space. Which of the following is the next best step in management?

A. Emergency laparotomy (Correct Answer)
B. Abdominal radiograph
C. Abdominal CT
D. Fluid resuscitation
E. Diagnostic peritoneal lavage

Explanation: ***Emergency laparotomy*** - The patient presents with **hemodynamic instability** (BP 82/51 mmHg, HR 136/min) and a **positive FAST exam** showing fluid in the perisplenic space, indicating intra-abdominal hemorrhage. - According to **ATLS guidelines**, a hemodynamically unstable patient with a positive FAST exam requires **immediate operative intervention** to control bleeding. This is the definitive management for ongoing hemorrhage. - While fluid resuscitation is initiated simultaneously (en route to OR), **surgical control of the bleeding source** is the priority and should not be delayed. *Fluid resuscitation* - Fluid resuscitation with IV crystalloids is essential and should be started immediately in this patient with hypovolemic shock. - However, in a patient with **uncontrolled intra-abdominal hemorrhage** (positive FAST, hemodynamic instability), fluids alone will not stop the bleeding. Continued fluid resuscitation without surgical intervention can lead to dilutional coagulopathy and worsening outcomes. - Fluid resuscitation occurs **concurrently with preparation for surgery**, not as a separate step that delays definitive management. *Diagnostic peritoneal lavage* - DPL is an invasive diagnostic procedure that has largely been replaced by FAST exam in modern trauma care. - Given that the **FAST is already positive**, DPL would provide no additional useful information and would only **delay definitive surgical management**. - In hemodynamically unstable patients with positive FAST, proceeding directly to laparotomy is indicated. *Abdominal radiograph* - Plain radiographs have **limited sensitivity** for detecting intra-abdominal bleeding or solid organ injury. - They may show free air (indicating hollow viscus perforation) but cannot assess for fluid or characterize solid organ injuries. - This would **delay necessary operative intervention** without providing actionable information. *Abdominal CT* - CT abdomen is the imaging modality of choice for **hemodynamically stable** trauma patients to characterize injuries and guide management. - For **unstable patients**, CT is **contraindicated** as it delays definitive treatment and removes the patient from a resuscitation environment where deterioration can be immediately addressed.

Question 9: Three hours after undergoing open proctocolectomy for ulcerative colitis, a 42-year-old male complains of abdominal pain. The pain is localized to the periumbilical and hypogastric regions. A total of 20 mL of urine has drained from his urinary catheter since the end of the procedure. Temperature is 37.2°C (98.9°F), pulse is 92/min, respirations are 12/min, and blood pressure is 110/72 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 99%. Physical examination shows a 20 cm vertical midline incision and an ileostomy in the right lower quadrant. There is no fluid drainage from the surgical wounds. The urinary catheter flushes easily and is without obstruction. Cardiopulmonary examination shows no abnormalities. Serum studies show a blood urea nitrogen of 30 mg/dL and a creatinine of 1.3 mg/dL. Which of the following is the most appropriate next step in management?

A. Administer tamsulosin
B. Administer intravenous furosemide
C. Obtain an abdominal CT
D. Start ciprofloxacin
E. Administer intravenous fluids (Correct Answer)

Explanation: ***Administer intravenous fluids*** - The patient's **oliguria** (20 mL urine over 3 hours, ~7 mL/hour) post-surgery, elevated **BUN (30 mg/dL)**, and **creatinine (1.3 mg/dL)** with a **BUN:Cr ratio >20:1** suggest **prerenal acute kidney injury** due to **hypovolemia**. - Post-operative fluid losses from **third-spacing**, blood loss, and insensible losses commonly cause hypovolemia after major abdominal surgery. - **Intravenous fluids** are the most appropriate initial step to restore intravascular volume and improve renal perfusion. *Administer tamsulosin* - **Tamsulosin** is an alpha-blocker used to relax smooth muscle in the prostate and bladder neck, primarily for **urinary retention** due to benign prostatic hyperplasia. - This patient's oliguria is due to **prerenal azotemia** from hypovolemia, not prostatic obstruction, and the catheter flushes easily without obstruction. *Administer intravenous furosemide* - **Furosemide** is a loop diuretic that increases urine output, but administering it in the context of **prerenal acute kidney injury** can worsen hypovolemia and further compromise renal function. - Diuretics are generally contraindicated in oliguria due to hypovolemia and should only be considered after volume resuscitation. *Obtain an abdominal CT* - While an abdominal CT can diagnose surgical complications, there are no immediate signs of a surgical emergency like **anastomotic leak** or **bowel obstruction**. - Addressing the likely **hypovolemia** is more urgent and should precede further imaging in this scenario. *Start ciprofloxacin* - The patient does not show signs of infection, such as fever or localized signs of bacterial peritonitis, making **antibiotics** like ciprofloxacin inappropriate as the initial management step. - The elevated BUN and creatinine are more indicative of volume depletion than infection.

Question 10: A 45-year-old man is brought to the emergency department following a house fire. Following initial stabilization, the patient is transferred to the ICU for management of his third-degree burn injuries. On the second day of hospitalization, a routine laboratory panel is obtained, and the results are demonstrated below. Per the nurse, he remains stable compared to the day prior. His temperature is 99°F (37°C), blood pressure is 92/64 mmHg, pulse is 98/min, respirations are 14/min, and SpO2 is 98%. A physical examination demonstrates an unresponsive patient with extensive burn injuries throughout his torso and lower extremities. Hemoglobin: 13 g/dL Hematocrit: 36% Leukocyte count: 10,670/mm^3 with normal differential Platelet count: 180,000/mm^3 Serum: Na+: 135 mEq/L Cl-: 98 mEq/L K+: 4.7 mEq/L HCO3-: 25 mEq/L BUN: 10 mg/dL Glucose: 123 mg/dL Creatinine: 1.8 mg/dL Thyroid-stimulating hormone: 4.3 µU/mL Triiodothyronine: 48 ng/dL Thyroxine: 10 ug/dL Ca2+: 8.7 mg/dL AST: 89 U/L ALT: 135 U/L What is the best course of management for this patient?

A. Continued management of his burn wounds (Correct Answer)
B. Increase opioid dosage
C. Start patient on intravenous ceftriaxone and vancomycin
D. Regular levothyroxine sodium injections
E. Immediate administration of propranolol

Explanation: ***Continued management of his burn wounds*** - The patient, despite extensive third-degree burns and several laboratory abnormalities, is **hemodynamically stable**, afebrile, and has an unremarkable white blood cell count and differential, indicating no immediate need for aggressive interventions beyond ongoing burn care. - The abnormal laboratory values (e.g., elevated creatinine, AST/ALT, low T3) are common in critically ill patients with severe burns and often represent **"sick euthyroid syndrome"** or systemic stress responses rather than primary organ dysfunction requiring specific drug therapy. *Increase opioid dosage* - While burn patients experience significant pain, the patient is described as **unresponsive**, suggesting that his current pain management is likely adequate or that he is not consciously perceiving pain. - Increasing opioids in an unresponsive patient could lead to **respiratory depression** and further hemodynamic compromise, which is not indicated given his current stable vital signs. *Start patient on intravenous ceftriaxone and vancomycin* - Although burn wounds are prone to infection, the patient's **normal temperature**, stable vital signs, and **unremarkable leukocyte count** and differential do not suggest an active bacterial infection requiring broad-spectrum antibiotics at this time. - Prophylactic antibiotic use in burn patients is generally **discouraged** due to the risk of promoting antibiotic resistance and fungal infections. *Immediate administration of propanolol* - Propranolol is sometimes used in severe burn patients to modulate the hypermetabolic response, but this is typically a **long-term management strategy**, not an immediate intervention in the acute phase, especially with a BP of 92/64 mmHg. - Given his slightly low blood pressure, administering a beta-blocker like propranolol could **worsen hypotension** and reduce cardiac output. *Regular levothyroxine sodium injections* - The patient's low T3 and normal TSH are consistent with **"euthyroid sick syndrome,"** a common adaptive response to critical illness, including severe burns. - In euthyroid sick syndrome, **thyroid hormone replacement is not indicated** and may even be harmful, as it does not improve outcomes and can exacerbate catecholamine effects.

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