Fluid and electrolyte management

Fluid and electrolyte management US Medical PG Question 1: A physician at an internal medicine ward notices that several of his patients have hyponatremia without any associated symptoms. Severe hyponatremia, often defined as < 120 mEq/L, is associated with altered mental status, coma, and seizures, and warrants treatment with hypertonic saline. Because some patients are chronically hyponatremic, with serum levels < 120 mEq/L, but remain asymptomatic, the physician is considering decreasing the cutoff for severe hyponatremia to < 115 mEq/L. Changing the cutoff to < 115 mEq/L would affect the validity of serum sodium in predicting severe hyponatremia requiring hypertonic saline in which of the following ways?

• A. Increased sensitivity and decreased positive predictive value
• B. Increased specificity and decreased positive predictive value
• C. Decreased specificity and increased negative predictive value
• D. Increased specificity and decreased negative predictive value (Correct Answer)
• E. Decreased sensitivity and decreased positive predictive value

Fluid and electrolyte management Explanation: ***Increased specificity and decreased negative predictive value*** - **Increasing the cutoff from <120 to <115 mEq/L makes the diagnostic criteria MORE STRINGENT** (fewer patients classified as "severe"). - **Specificity INCREASES**: With a stricter cutoff, fewer patients without true severe disease (asymptomatic chronic hyponatremia) will be falsely labeled as "severe" and unnecessarily treated with hypertonic saline. Specificity measures the ability to correctly identify patients who do NOT have the target condition (symptomatic severe hyponatremia requiring treatment). - **Negative Predictive Value (NPV) DECREASES**: Patients with sodium levels between 115-120 mEq/L will now test "negative" for severe hyponatremia (falling above the new threshold), but some of these patients may still develop symptoms requiring treatment. Therefore, a "negative" test result (Na >115) becomes less reliable at ruling out the need for future treatment, decreasing NPV. - **Note**: Sensitivity will DECREASE (more symptomatic patients with Na 115-120 will be missed), and PPV will INCREASE (those identified as severe are more likely to truly need treatment). *Increased sensitivity and decreased positive predictive value* - Moving the cutoff to a more stringent value (<115 mEq/L) would **decrease sensitivity**, not increase it, because patients with sodium 115-120 mEq/L who have symptoms would be missed. - The positive predictive value would **increase**, not decrease, because patients classified as "severe" under the stricter criteria are more likely to truly require hypertonic saline. *Increased specificity and decreased positive predictive value* - **Increased specificity** is correct, as explained above. - However, **PPV would increase**, not decrease, with a more stringent cutoff. When fewer patients are classified as "severe," those who meet the stricter criteria are more likely to truly have severe disease requiring treatment. *Decreased specificity and increased negative predictive value* - Specificity would **increase**, not decrease, with stricter diagnostic criteria (fewer false positives). - NPV would **decrease**, not increase, because patients just above the new threshold (Na 115-120) who test "negative" may still require treatment. *Decreased sensitivity and decreased positive predictive value* - **Decreased sensitivity** is correct—the stricter cutoff will miss symptomatic patients with sodium 115-120 mEq/L. - However, **PPV would increase**, not decrease. With stricter criteria, patients identified as "severe" are more likely to truly have severe disease requiring hypertonic saline.

Fluid and electrolyte management US Medical PG 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

Fluid and electrolyte management 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.

Fluid and electrolyte management US Medical PG Question 3: A 46-year-old woman presents to the clinic complaining that she “wets herself.” She states that over the past year she has noticed increased urinary leakage. At first it occurred only during her job, which involves restocking shelves with heavy appliances. Now she reports that she has to wear pads daily because leakage of urine will occur with simply coughing or sneezing. She denies fever, chills, dysuria, hematuria, or flank pain. She has no significant medical or surgical history, and takes no medications. Her last menstrual period was 8 months ago. She has 3 healthy daughters that were born by vaginal delivery. Which of the following tests, if performed, would most likely identify the patient’s diagnosis?

• A. Methylene blue dye
• B. Post-void residual volume
• C. Urodynamic testing
• D. Estrogen level
• E. Q-tip test (Correct Answer)

Fluid and electrolyte management Explanation: ***Q-tip test*** - The patient's symptoms (leakage with coughing/sneezing, lifting heavy objects, vaginal deliveries, recent cessation of menses) are classic for **stress urinary incontinence**, often due to **urethral hypermobility**. - The **Q-tip test** assesses urethral hypermobility by measuring the angle of deflection of a sterile cotton swab inserted into the urethra during a Valsalva maneuver. An angle >30 degrees from the horizontal indicates hypermobility. *Methylene blue dye* - **Methylene blue dye** is primarily used to identify **vesicovaginal or ureterovaginal fistulas**, where dye would be seen leaking into the vagina. - The patient's symptoms do not suggest a fistula, but rather a problem with sphincter control during increased abdominal pressure. *Post-void residual volume* - **Post-void residual volume (PVR)** measures the amount of urine left in the bladder after urination, primarily used to diagnose **overflow incontinence** or **urinary retention**. - The patient's symptoms are inconsistent with overflow incontinence, which typically involves frequent dribbling or incomplete emptying rather than leakage specifically with physical exertion. *Urodynamic testing* - **Urodynamic testing** is a more comprehensive and invasive evaluation that includes cystometry, pressure-flow studies, and electromyography, often used to differentiate types of incontinence when the diagnosis is unclear. - While it can diagnose stress incontinence, less invasive tests like the Q-tip test are typically preferred as a first step for **urethral hypermobility** before proceeding to complex urodynamic studies. *Estrogen level* - An **estrogen level** might be relevant if **atrophic vaginitis** or **urethritis** due to estrogen deficiency were suspected, which can contribute to urgency or mixed incontinence. - While the patient is peri-menopausal, her primary symptoms (leakage with exertion) are more indicative of structural weakness (stress incontinence) rather than estrogen-related tissue atrophy or inflammation.

Fluid and electrolyte management US Medical PG Question 4: The serum brain natriuretic peptide and N-terminal pro-BNP are elevated. A diagnosis of heart failure with preserved ejection fraction is made. In addition to supplemental oxygen therapy, which of the following is the most appropriate initial step in management?

• A. Intravenous dobutamine
• B. Intravenous furosemide therapy (Correct Answer)
• C. Intravenous morphine therapy
• D. Thoracentesis
• E. Intermittent hemodialysis

Fluid and electrolyte management Explanation: ***Intravenous furosemide therapy*** - Heart failure with **preserved ejection fraction (HFpEF)** often presents with **pulmonary congestion** due to elevated filling pressures. - **Furosemide**, a loop diuretic, effectively reduces fluid overload and associated symptoms by increasing renal excretion of sodium and water. *Intravenous dobutamine* - **Dobutamine** is an inotropic agent that increases myocardial contractility and heart rate. - It is typically used for **acute decompensated heart failure with low cardiac output** and is generally avoided in HFpEF unless there is significant hypoperfusion, as it can worsen myocardial oxygen demand and diastolic dysfunction. *Intravenous morphine therapy* - **Morphine** can be used in acute heart failure to reduce preload and anxiety, but it is not a primary treatment for the underlying fluid overload. - It can cause respiratory depression and hypotension, and its use is typically reserved for patients with severe pain or dyspnea not adequately managed by other therapies. *Thoracentesis* - **Thoracentesis** is indicated for symptomatic **pleural effusions** causing respiratory distress. - While pleural effusions can occur in heart failure, initial management of generalized fluid overload typically involves diuretics, making thoracentesis a secondary intervention if diuretic therapy is insufficient. *Intermittent hemodialysis* - **Intermittent hemodialysis** is an invasive procedure primarily used for severe renal failure or refractory fluid overload that has not responded to maximal diuretic therapy. - It is not the initial step in managing heart failure with preserved ejection fraction and would only be considered in highly selected cases with **acute kidney injury** or diuretic resistance.

Fluid and electrolyte management US Medical PG Question 5: On cardiology service rounds, your team sees a patient admitted with an acute congestive heart failure exacerbation. In congestive heart failure, decreased cardiac function leads to decreased renal perfusion, which eventually leads to excess volume retention. To test your knowledge of physiology, your attending asks you which segment of the nephron is responsible for the majority of water absorption. Which of the following is a correct pairing of the segment of the nephron that reabsorbs the majority of all filtered water with the means by which that segment absorbs water?

• A. Distal convoluted tubule via passive diffusion following ion reabsorption
• B. Distal convoluted tubule via aquaporin channels
• C. Thick ascending loop of Henle via passive diffusion following ion reabsorption
• D. Proximal convoluted tubule via passive diffusion following ion reabsorption (Correct Answer)
• E. Collecting duct via aquaporin channels

Fluid and electrolyte management Explanation: ***Proximal convoluted tubule via passive diffusion following ion reabsorption*** - The **proximal convoluted tubule (PCT)** is responsible for reabsorbing approximately **65-70% of filtered water**, making it the primary site of water reabsorption in the nephron. - This water reabsorption primarily occurs **passively**, following the active reabsorption of solutes (especially **sodium ions**), which creates an osmotic gradient. *Distal convoluted tubule via passive diffusion following ion reabsorption* - The **distal convoluted tubule (DCT)** reabsorbs a much smaller percentage of filtered water (around 5-10%) and its water reabsorption is largely **regulated by ADH**, not primarily simple passive diffusion following bulk ion reabsorption. - While some passive water movement occurs, it is not the main mechanism or location for the majority of water reabsorption. *Distal convoluted tubule via aquaporin channels* - While aquaporin channels do play a role in water reabsorption in the DCT, particularly under the influence of **ADH**, the DCT is not the segment responsible for the **majority of all filtered water absorption**. - The bulk of water reabsorption occurs earlier in the nephron, independently of ADH for the most part. *Thick ascending loop of Henle via passive diffusion following ion reabsorption* - The **thick ascending loop of Henle** is primarily involved in reabsorbing ions like Na+, K+, and Cl- but is largely **impermeable to water**. - Its impermeability to water is crucial for creating the **osmotic gradient** in the renal medulla, which is necessary for later water reabsorption. *Collecting duct via aquaporin channels* - The **collecting duct** is critically important for **regulated water reabsorption** via **aquaporin-2 channels** under the influence of **ADH**, allowing for fine-tuning of urine concentration. - However, it reabsorbs only a variable portion (typically 5-19%) of the remaining filtered water, not the **majority of all filtered water**.

Fluid and electrolyte management US Medical PG Question 6: A 21-year-old woman is admitted to the hospital for severe malnutrition with a BMI of 15 kg/m2. Past medical history is significant for chronic anorexia nervosa. During the course of her stay, she is treated with parenteral fluids and nutrition management. On the 4th day, her status changes. Her blood pressure is 110/75 mm Hg, heart rate is 120/min, respiratory rate is 25/min, and temperature is 37.0°C (98.6°F). On physical exam, her heart is tachycardic with a regular rhythm and her lungs are clear to auscultation bilaterally. She appears confused, disoriented, and agitated. Strength in her lower extremities is 4/5. What is the next step in management?

• A. MRI of the brain
• B. Administer insulin
• C. Measure electrolytes (Correct Answer)
• D. Arrange for outpatient counseling
• E. Doppler ultrasound on lower extremities

Fluid and electrolyte management Explanation: ***Measure electrolytes*** - The patient's presentation with **confusion, disorientation, agitation**, and **lower extremity weakness** after refeeding for severe **malnutrition** is highly suggestive of **refeeding syndrome**. This syndrome is characterized by severe electrolyte shifts, particularly **hypophosphatemia**, **hypokalemia**, and **hypomagnesemia**. - Measuring electrolytes immediately is crucial to diagnose and then correct these imbalances, which can lead to life-threatening complications like **cardiac arrhythmias**, **respiratory failure**, and **seizures**. *MRI of the brain* - While neurological symptoms are present, a brain MRI is not the immediate first step given the context of refeeding in a severely malnourished patient. - The symptoms are more consistent with **metabolic derangements** associated with **refeeding syndrome** than an acute primary neurological event. *Administer insulin* - Administering insulin without knowing the patient's glucose or electrolyte status could be dangerous, especially given the increased risk of **hypokalemia** and **hypophosphatemia** in refeeding syndrome, which insulin can exacerbate. - Refeeding syndrome typically involves glucose shifts, but **hypoglycemia** is not the primary immediate concern, and hyperinsulinemia in this context can cause cellular uptake of electrolytes leading to further depletion. *Arrange for outpatient counseling* - The patient is acutely ill and experiencing a potentially life-threatening complication requiring immediate medical intervention. - **Outpatient counseling** is not appropriate for an acute hospital admission with severe, rapidly changing symptoms. *Doppler ultrasound on lower extremities* - While immobility can increase the risk of deep vein thrombosis (DVT), the patient's symptoms of **confusion, agitation, tachycardia, tachypnea**, and **weakness** are not primary indicators of DVT. - The clinical picture points strongly towards **metabolic complications** of refeeding.

Fluid and electrolyte management US Medical PG Question 7: A 45-year-old man presents to the physician with limb weakness over the last 24 hours. He is an otherwise healthy man with no significant past medical history. On physical examination, his vital signs are stable. On neurological examination, there is decreased strength in the muscles of all 4 extremities, and the deep tendon reflexes are depressed. A detailed laboratory evaluation shows that he has generalized decreased neuronal excitability due to an electrolyte imbalance. Which of the following electrolyte imbalances is most likely to be present in the man?

• A. Acute hypochloremia
• B. Acute hypernatremia
• C. Acute hyperkalemia
• D. Acute hypercalcemia (Correct Answer)
• E. Acute hypomagnesemia

Fluid and electrolyte management Explanation: ***Acute hypercalcemia*** - **Hypercalcemia** causes decreased neuronal excitability by stabilizing nerve cell membranes, leading to **muscle weakness** and depressed deep tendon reflexes. - The generalized weakness and hyporeflexia described are classic neurological manifestations of elevated calcium levels. *Acute hypochloremia* - **Hypochloremia** is often associated with gastrointestinal losses and can lead to **metabolic alkalosis** and muscle cramps but not generalized muscle weakness with depressed reflexes. - Its direct effect on neuronal excitability to cause such profound weakness is not typical. *Acute hypernatremia* - **Hypernatremia** primarily causes neurological symptoms due to **cellular dehydration** and cerebral edema, leading to altered mental status, seizures, or coma. - It does not typically present with generalized muscle weakness and depressed deep tendon reflexes due to decreased neuronal excitability in the manner described. *Acute hyperkalemia* - **Hyperkalemia** can cause muscle weakness and paralysis, but it often progresses to **cardiac arrhythmias** and is typically associated with **increased neuronal excitability** initially, before paralyzing effects. - While it can lead to weakness, the generalized decreased excitability described is more characteristic of calcium imbalance. *Acute hypomagnesemia* - **Hypomagnesemia** typically increases neuronal excitability, leading to symptoms like **muscle cramps**, tremors, hyperreflexia, and even seizures. - It does not cause generalized muscle weakness with depressed deep tendon reflexes as a primary manifestation of decreased neuronal excitability.

Fluid and electrolyte management US Medical PG Question 8: 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)

Fluid and electrolyte management 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.

Fluid and electrolyte management US Medical PG Question 9: A 78-year-old male with history of coronary artery disease, status post coronary stent placement currently on aspirin and clopidogrel was found down in his bathroom by his wife. His GCS score was 3 and an accurate physical exam is limited. A stat non-contrast CT scan of his brain demonstrated a large right parietal intracranial hemorrhage with surrounding edema. He was promptly transferred to the intensive care unit (ICU) for monitoring. Over the next day, his mental status continues to worsen but repeat CT scan shows no new bleeding. In addition, the patient’s urinary output has been >200 cc/hr over the last several hours and increasing. His temperature is 99.0 deg F (37.2 deg C), blood pressure is 125/72 mmHg, pulse is 87/min, and respirations are 13/min. Which of the following values would most likely correspond to the patient’s urine specific gravity, urine osmolality, plasma osmolality, and serum sodium?

• A. Low, High, High, High
• B. Low, Low, High, High (Correct Answer)
• C. High, High, Low, Low
• D. Low, Low, High, Low
• E. High, Low, Low, High

Fluid and electrolyte management Explanation: ***Low, Low, High, High*** - This patient's presentation, particularly the **large intracranial hemorrhage**, worsening mental status despite no new bleeding, and especially the **high urinary output (>200 cc/hr)**, is classic for **diabetes insipidus (DI)**, often neurogenic DI, due to damage to the posterior pituitary or hypothalamus. - In DI, there is a deficiency of **ADH (vasopressin)**, leading to the kidneys' inability to reabsorb water. This results in the excretion of large volumes of **dilute urine** (low urine specific gravity, low urine osmolality) and concentration of the plasma (high plasma osmolality and hypernatremia, which means high serum sodium). *Low, High, High, High* - This pattern would indicate concentrated urine alongside concentrated plasma and high sodium, which contradicts the presence of **polyuria** and the underlying pathology of **diabetes insipidus (DI)**. - High urine osmolality and specific gravity would suggest intact ADH function and water reabsorption in the kidneys, which is not what occurs in DI. *High, High, Low, Low* - This profile describes a state of **concentrated urine** but **dilute plasma** and **hyponatremia**, which is characteristic of the **Syndrome of Inappropriate Antidiuretic Hormone (SIADH)**. - SIADH is the opposite of diabetes insipidus, involving excessive ADH leading to water retention, not excessive water excretion. *Low, Low, High, Low* - While **low urine specific gravity** and **low urine osmolality** are consistent with diabetes insipidus, a **low serum sodium** (hyponatremia) is not. - In diabetes insipidus, the loss of free water typically leads to **hypernatremia** as the body becomes dehydrated. *High, Low, Low, High* - This combination is inconsistent with any common clinical scenario. A **high urine specific gravity** with a **low urine osmolality** is contradictory, as specific gravity is a measure of urine concentration, which correlates with osmolality. - Furthermore, a **low plasma osmolality** with a **high serum sodium** is physiologically improbable.

Fluid and electrolyte management US Medical PG Question 10: 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

Fluid and electrolyte management 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.

Fluid and electrolyte management Flashcard 1 of 7

Question: EF < _____% and MI within _____ months are absolute contraindications to non-cardiac surgery

Answer: 35

Extra Information:  https://onlinemeded.org/spa/surgery?ref=anki 

Fluid and electrolyte management Flashcard 2 of 7

Question: Increased pressure within a fascial compartment of a limb experiencing Compartment Syndrome is defined by a fascial compartment pressure to diastolic pressure gradient of _____

Answer: < 30 mmHg

Fluid and electrolyte management Flashcard 3 of 7

Question: A _____ is indicated when an emergency airway is required or orotracheal / nasotracheal intubation is unsuccessful / contraindicated

Answer: cricothyrotomy

Fluid and electrolyte management Flashcard 4 of 7

Question: ACL injures are characterized by rapid-onset _____ and knee swelling

Answer: hemarthrosis

Fluid and electrolyte management Flashcard 5 of 7

Question: An entire leg burn is _____% of the body surface area.

Answer: 18

Fluid and electrolyte management Flashcard 6 of 7

Question: Patients who have undergone _____ surgery can sometimes manifest with symptoms of hypoparathyroidism and hypocalcemia.

Answer: Thyroid

Fluid and electrolyte management Flashcard 7 of 7

Question: Neuro/Psych _____ is a skeletal muscle hypersensitivity to volatile anesthetics

Answer: Malignant hyperthermia