Plasma Expanders — MCQs
Best solution to be used in hypovolemic shock is:
Initial fluid of choice in treatment of hypovolemia in patients presenting after trauma is
What is Hydroxyethyl starch?
A patient is in shock with gross comminuted fracture. The first step in management is to give
What is the preferred fluid in a poly-traumatic patient with shock?
Which of the following drugs decreases plasma renin activity
All of the following are true about the action of ADH, except:
Which of the following are advantages of state of haemodilution during pregnancy? 1. Optimum gaseous exchange between maternal and foetal circulation due to decreased blood viscosity 2. Protection against adverse effect of blood loss during delivery 3. Increased oxygen carrying capacity of blood Select the correct answer using the code given below.
Free water clearance is decreased by?
20 mEq (mmol) of potassium chloride in 500 ml of 5% dextrose solution is given intravenously to treat-
Plasma Expanders Indian Medical PG Practice Questions and MCQs
Question 1: Best solution to be used in hypovolemic shock is:
- A. Ringer's Lactate solution. (Correct Answer)
- B. Darrow's solution.
- C. 5% dextrose.
- D. 0.9% Nacl.
Explanation: ***Ringer's Lactate solution*** - This **isotonic crystalloid solution** is commonly used in hypovolemic shock because its electrolyte composition is similar to that of human plasma. [2] - The **lactate** component is metabolized by the liver to bicarbonate, which helps to buffer acidosis often associated with shock. [2] *Darrow's solution* - Darrow's solution is a **hypertonic solution** containing high concentrations of potassium, primarily used for severe dehydration and significant potassium deficits, not initial fluid resuscitation in hypovolemic shock. - Its high potassium content can be dangerous in patients with **renal impairment** or who are already hyperkalemic. *5% dextrose* - **5% dextrose in water (D5W)** is an initially isotonic solution, but the dextrose is quickly metabolized, making it effectively a hypotonic solution. [2] - It is primarily used to provide **free water** and is not effective for volume expansion in hypovolemic shock as it does not stay in the intravascular space. [2] *0.9% Nacl* - **0.9% normal saline** is an isotonic crystalloid often used for volume resuscitation but has a higher chloride content than plasma, which can lead to **hyperchloremic metabolic acidosis** with large volumes. [1], [2] - While it expands the intravascular space, Ringer's Lactate is often preferred in situations of significant blood loss or acidosis due to its more balanced electrolyte profile and buffering capacity. [2]
Question 2: Initial fluid of choice in treatment of hypovolemia in patients presenting after trauma is
- A. Blood
- B. Colloid
- C. Plasma expanders
- D. Crystalloid (Correct Answer)
Explanation: ***Crystalloid*** - **Crystalloids** such as normal saline or lactated Ringer's solution are the initial fluid of choice for **hypovolemia in trauma patients** due to their ready availability, low cost, and effectiveness in rapidly expanding the intravascular volume. - They freely distribute across the extracellular space, effectively compensating for fluid loss and supporting organ perfusion. *Blood* - While essential for significant **hemorrhage**, blood products are typically reserved for patients who do not respond to crystalloid resuscitation or have documented severe blood loss. - Transfusion carries risks such as **transfusion reactions**, and blood preparation and cross-matching take time, making them less suitable for initial, rapid fluid replacement. *Colloid* - **Colloids** (e.g., albumin, starches) are larger molecules that theoretically remain in the intravascular space longer, but their benefits over crystalloids in trauma are controversial and they are significantly more expensive. - Some colloids have been associated with adverse effects like **renal dysfunction** or **coagulopathy**, making crystalloids a safer initial option. *Plasma expanders* - **Plasma expanders** is a broad term that includes both colloids and some hypertonic crystalloid solutions, but it is not commonly used as a primary, specific category for initial fluid resuscitation. - The potential benefits of these agents are still debated, and they are typically not recommended as the first-line choice in the acute management of **traumatic hypovolemic shock**.
Question 3: What is Hydroxyethyl starch?
- A. Vasodilator
- B. Inotrope
- C. Plasma expander (Correct Answer)
- D. Diuretic
Explanation: ***Plasma expander*** - **Hydroxyethyl starch** is a **colloid solution** used intravenously to increase plasma volume and maintain oncotic pressure. - It is often used in situations of **hypovolemia** or shock to support circulation. *Vasodilator* - A **vasodilator** is a medication that widens blood vessels, typically used to lower blood pressure or improve blood flow. - Hydroxyethyl starch does not directly cause **vasodilation** as its primary mechanism of action. *Inotrope* - An **inotrope** is an agent that alters the force or energy of muscular contractions, mainly affecting the heart's contractility. - Hydroxyethyl starch has no direct effect on **myocardial contractility**. *Diuretic* - A **diuretic** is a substance that promotes increased production of urine, thereby increasing the excretion of water from the body. - While fluid administration can temporarily increase urine output, hydroxyethyl starch is not classified as a **diuretic agent** itself.
Question 4: A patient is in shock with gross comminuted fracture. The first step in management is to give
- A. Blood transfusion
- B. Ringer's Lactate solution intravenously (Correct Answer)
- C. Plasma expanders
- D. Normal saline intravenously
Explanation: ***Ringer's Lactate solution intravenously*** - In cases of **hypovolemic shock**, the immediate priority is to restore circulating volume with an **isotonic crystalloid solution** like **Ringer's Lactate**. - This helps to stabilize hemodynamics and perfuse vital organs, while other measures are prepared. *Blood transfusion* - While blood loss is a concern in gross comminuted fractures, **blood transfusions** are generally reserved for more severe, confirmed blood loss and are often given after initial crystalloid resuscitation. - Type-specific or cross-matched blood may take time to prepare and administer. *Plasma expanders* - **Plasma expanders** (e.g., colloids) are alternatives but are generally not the first-line choice over crystalloids for initial resuscitation in trauma, due to their higher cost and potential side effects, with no clear survival benefit. - They also do not address the acute need for volume replacement as effectively as initial rapid infusion of crystalloids. *Normal saline intravenously* - **Normal saline** is an isotonic crystalloid and could be used; however, **Ringer's Lactate** is often preferred in large volumes for trauma and shock patients because its balanced electrolyte composition closer to plasma may help to prevent **hyperchloremic acidosis**. - While not as detrimental as in very large volumes, normal saline can contribute to metabolic acidosis when given in excessive amounts.
Question 5: What is the preferred fluid in a poly-traumatic patient with shock?
- A. Ringer lactate (Correct Answer)
- B. Dextran
- C. Normal saline
- D. Dextrose-normal saline
Explanation: ***Ringer lactate*** - **Ringer's lactate (RL)** is the **preferred initial resuscitation fluid** for poly-traumatic patients with shock according to **ATLS (Advanced Trauma Life Support) guidelines**. - It is a **balanced crystalloid** with electrolyte composition similar to plasma, providing effective volume expansion while minimizing the risk of **hyperchloremic metabolic acidosis** that occurs with large-volume normal saline administration. - The lactate in RL is rapidly metabolized to bicarbonate by the liver, helping to buffer any existing acidosis, and does not worsen lactic acidosis in trauma patients. - RL also contains **potassium and calcium**, which help maintain physiological electrolyte balance during resuscitation. *Normal saline* - While **normal saline (0.9% NaCl)** is an isotonic crystalloid, it has a **supraphysiological chloride concentration** (154 mEq/L) compared to plasma (100 mEq/L). - Large-volume administration in trauma can cause **hyperchloremic metabolic acidosis**, which can worsen outcomes and is particularly problematic in poly-trauma patients already at risk for metabolic derangements. - It remains acceptable as an alternative when RL is unavailable, but is no longer considered the first-line choice in modern trauma protocols. *Dextran* - **Dextran** is a colloid solution that carries significant risks including **anaphylactic reactions** and **coagulopathy** by interfering with platelet function and clotting factors. - These adverse effects are particularly dangerous in poly-traumatic patients who may already have traumatic coagulopathy. - It is **not recommended** for initial trauma resuscitation due to these risks and lack of proven superiority over crystalloids. *Dextrose-normal saline* - **Dextrose-containing solutions** are hypotonic after dextrose metabolism, leading to ineffective intravascular volume expansion as fluid shifts into the intracellular compartment. - They can worsen **cerebral edema** in head-injured trauma patients and cause dangerous electrolyte imbalances. - These solutions are **contraindicated** in acute trauma resuscitation.
Question 6: Which of the following drugs decreases plasma renin activity
- A. Nifedipine
- B. Hydralazine
- C. Enalapril
- D. Clonidine (Correct Answer)
Explanation: ***Clonidine*** - **Clonidine** is a centrally acting alpha-2 adrenergic agonist that reduces **sympathetic outflow** from the brainstem. - This reduction in sympathetic activity leads to decreased release of **norepinephrine**, which in turn reduces renin secretion by the kidneys. *Nifedipine* - **Nifedipine** is a **dihydropyridine calcium channel blocker** that causes peripheral vasodilation. - The vasodilation often leads to a **reflex increase in sympathetic activity** and, consequently, an increase in plasma renin activity. *Hydralazine* - **Hydralazine** is a direct systemic **vasodilator** that decreases peripheral vascular resistance. - This vasodilation can cause a **reflex increase in sympathetic activity** and **renin release** as the body tries to compensate for the drop in blood pressure. *Enalapril* - **Enalapril** is an **ACE inhibitor** that blocks the conversion of angiotensin I to angiotensin II. - This action directly leads to **increased plasma renin activity** due to the disruption of the negative feedback loop on renin release.
Question 7: All of the following are true about the action of ADH, except:
- A. Acts on collecting ducts and increases water permeability
- B. Secreted by neurosecretion from posterior pituitary
- C. Post-operative increase in secretion
- D. Increased secretion when plasma osmolality is low (Correct Answer)
Explanation: ***Increased secretion when plasma osmolality is low*** - **Antidiuretic hormone (ADH)** secretion is *inhibited* when plasma osmolality is low. - ADH is secreted to conserve water and *increase* plasma osmolality when it is too high, or plasma volume is too low. - Normal osmolality range is 280-290 mOsm/kg; ADH secretion increases above this threshold. *Acts on collecting ducts and increases water permeability* - This statement is true; ADH binds to **V2 receptors** on the principal cells of the collecting ducts. - This binding leads to the insertion of **aquaporin-2 channels** into the apical membrane, increasing water reabsorption. *Secreted by neurosecretion from posterior pituitary* - This statement is true; ADH is synthesized in the **hypothalamus** (supraoptic and paraventricular nuclei) and transported down nerve axons. - It is then stored in and released from the **posterior pituitary gland**, a process known as neurosecretion. *Post-operative increase in secretion* - This statement is true; surgical stress, pain, and common postoperative medications (e.g., narcotics) can stimulate ADH release. - This can lead to **hyponatremia** and fluid retention in the postoperative period due to excessive free water reabsorption.
Question 8: Which of the following are advantages of state of haemodilution during pregnancy? 1. Optimum gaseous exchange between maternal and foetal circulation due to decreased blood viscosity 2. Protection against adverse effect of blood loss during delivery 3. Increased oxygen carrying capacity of blood Select the correct answer using the code given below.
- A. 1, 2 and 3
- B. 1 and 3 only
- C. 2 and 3 only
- D. 1 and 2 only (Correct Answer)
Explanation: ***1 and 2 only*** - **Haemodilution** during pregnancy, characterized by a disproportionate increase in plasma volume relative to red blood cell mass, leads to decreased blood **viscosity**. - A lower blood viscosity facilitates more efficient **gaseous exchange** (oxygen and carbon dioxide) between the maternal and fetal circulations at the placenta, and also offers a degree of protection against the effects of **blood loss during delivery** by maintaining circulating volume. *1, 2 and 3* - While haemodilution promotes efficient gaseous exchange and protects against blood loss, it does **not increase the oxygen carrying capacity** of the blood. - In fact, the relative decrease in red blood cell concentration leads to physiological anemia of pregnancy, which reduces the oxygen-carrying capacity (though total oxygen delivery may be maintained by increased cardiac output). *2 and 3 only* - This option correctly identifies protection against blood loss but incorrectly states an **increased oxygen carrying capacity**. - The primary mechanism for improved oxygen delivery is enhanced blood flow due to reduced viscosity and increased cardiac output, not an increased concentration of oxygen carriers. *1 and 3 only* - This option correctly identifies improved gaseous exchange but incorrectly suggests an **increased oxygen carrying capacity**. - Protection against blood loss is a significant benefit of pregnancy-induced haemodilution, which is overlooked in this choice.
Question 9: Free water clearance is decreased by?
- A. Furosemide
- B. Vinblastine
- C. Vincristine
- D. Chlorpropamide (Correct Answer)
Explanation: ***Chlorpropamide*** - **Chlorpropamide** is a sulfonylurea oral hypoglycemic agent that is a **classic and well-documented cause of SIADH (Syndrome of Inappropriate Antidiuretic Hormone)**. - **SIADH** leads to increased ADH secretion, causing increased water reabsorption in the collecting ducts and thus **decreased free water clearance**. - Among the options listed, chlorpropamide is the **prototypical drug** associated with drug-induced SIADH in pharmacology teaching. *Furosemide* - **Furosemide** is a loop diuretic that inhibits the reabsorption of sodium and chloride in the **loop of Henle**. - This disrupts the medullary concentration gradient and leads to increased excretion of water and electrolytes, thereby **increasing free water clearance**. *Vinblastine* - **Vinblastine** is a vinca alkaloid chemotherapeutic agent primarily used in cancer treatment. - It does not significantly affect renal water handling or ADH secretion and does **not typically cause SIADH**. *Vincristine* - **Vincristine** is another vinca alkaloid chemotherapy drug that **can also cause SIADH** and decrease free water clearance. - However, in the context of standard pharmacology teaching and board examinations, **chlorpropamide** is the more classical example emphasized for drug-induced SIADH and decreased free water clearance. - Vincristine is primarily known for its **neurotoxicity** as a major side effect.
Question 10: 20 mEq (mmol) of potassium chloride in 500 ml of 5% dextrose solution is given intravenously to treat-
- A. Hypokalemia (Correct Answer)
- B. Hyperkalemia
- C. Hypernatremia
- D. Hyponatremia
Explanation: ***Hypokalemia*** - The administration of **potassium chloride (KCl)** is a direct method to **replenish potassium stores** in the body, effectively treating low serum potassium levels. - Adding KCl to an intravenous solution, such as **5% dextrose**, ensures systemic distribution to correct this electrolyte imbalance. *Hyperkalemia* - **Hyperkalemia** refers to dangerously high levels of potassium in the blood, so administering more potassium chloride would worsen this condition, not treat it. - Treatment for hyperkalemia typically involves measures to **shift potassium into cells** or **increase its excretion**, not supplementation. *Hypernatremia* - **Hypernatremia** is an elevated sodium level, usually caused by dehydration or excessive sodium intake. Giving potassium chloride would not directly address sodium balance. - Treatment primarily involves administering **hypotonic fluids** to dilute the excessive sodium. *Hyponatremia* - **Hyponatremia** is a low sodium level in the blood. While fluid management is crucial for hyponatremia, potassium chloride specifically targets potassium levels, not sodium. - For hyponatremia, treatment varies based on severity and acuity and often includes **sodium replacement** or fluid restriction.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free