Fluid & Electrolytes Practice Test #1: Fluid Volume Deficit and Excess

Answer: B. When the client stands, the heart rate rises from 88 to 112/min and the blood pressure falls from 128/76 to 104/62 mm Hg.

Rationale: Orthostatic (postural) changes are one of the clearest bedside signs that the circulating volume is low. When the client stands, blood pools in the legs, and with too little volume the heart rate climbs and the blood pressure drops (B). Commonly used criteria are a fall of about 20 mm Hg systolic or 10 mm Hg diastolic, or a heart rate rise of about 20/min or more, within a few minutes of standing; exact criteria vary, so the nurse follows facility policy and protects the client from falling during the check. Option A is wrong because high blood pressure and distended neck veins point to fluid volume excess. Option C is wrong because a specific gravity of 1.005 means dilute urine; with a deficit the kidneys hold on to water and the urine becomes concentrated, with a higher specific gravity. Option D is wrong because crackles suggest fluid in the lungs, which fits fluid volume excess.

Answer: D. New crackles in both lung bases, a bounding pulse, and SpO2 falling from 96% to 90%.

Rationale: New crackles, a bounding pulse and a falling oxygen saturation are signs of fluid volume excess that is moving into the lungs (D). A client with heart failure is at higher risk because the heart cannot handle the extra volume. The nurse slows the infusion to the rate allowed by the orders or facility protocol, raises the head of the bed, applies oxygen as ordered, stays with the client and notifies the provider right away. Option A is wrong because 50 mL in an hour is an adequate urine output for most adults; a common minimum is about 0.5 mL/kg/hr, though the target depends on the client. Option B is wrong because mild edema that has not changed since admission is not a new problem. Option C is wrong because thirst after surgery is common, and while it is worth noting, it is not the most urgent finding.

Answer: A. Compare the client's daily weights, taken on the same scale, at the same time of day, with similar clothing.

Rationale: Daily weight is the most accurate way to track changes in body fluid, because a quick change in weight reflects fluid rather than fat or muscle. A gain or loss of 1 kg is roughly equal to 1 liter of fluid (A). To make the numbers comparable, the nurse weighs the client on the same scale, at the same time of day (usually before breakfast and after voiding), with similar clothing. Option B is wrong because older adults lose skin elasticity, so skin turgor is less reliable in this age group; if it is checked, the sternum or forehead is often preferred over the back of the hand. Option C is wrong because the thirst response becomes weaker with age, so an older adult may not feel thirsty even when fluid is low. Option D is wrong because counting voids without measuring them does not show how much fluid is lost; accurate intake and output records measure the volume.

Answer: C. 0.9% sodium chloride or lactated Ringer's solution.

Rationale: Isotonic crystalloids such as 0.9% sodium chloride or lactated Ringer's solution are the usual first choice to restore circulating volume (C). They have about the same concentration as plasma, so they stay in the extracellular space, including the blood vessels, instead of shifting into the cells. The provider decides the exact fluid, volume and rate, and the nurse reassesses blood pressure, heart rate, mental status, urine output and lung sounds during and after the bolus. Option A is wrong because 0.45% sodium chloride is hypotonic; much of it moves into the cells, so it does little to raise blood pressure. Option B is wrong because once the dextrose is used by the body, D5W acts like free water and spreads into all fluid compartments, so very little stays in the blood vessels. Option D is wrong because 3% sodium chloride is a hypertonic solution used in specific situations, such as severe symptomatic hyponatremia, under close monitoring; it is not used to replace volume lost through diarrhea.

Answer: A. "Ice chips, gelatin and popsicles count toward my daily fluid limit."

Rationale: Any food that is liquid at room temperature counts as fluid, including ice chips, gelatin, popsicles, ice cream and soup (A). The client also counts the liquid taken with medicines. The amount of the restriction is set by the provider and depends on the client's condition. Helpful tips include spreading the allowed fluid through the day, using small cups, sucking on sugar-free hard candy and doing frequent mouth care. Option B is wrong because soup, broth and other liquids all count, not just water. Option C is wrong because alcohol-based mouthwash dries the mouth more; an alcohol-free rinse or plain water rinses that are spit out are better choices. Option D is wrong because skipping all fluids is not safe and can cause other problems; the client should follow the plan and tell the provider if keeping to the limit is hard.

Answer: C. Urine output has risen from 15 mL/hr to 45 mL/hr, and the heart rate has fallen from 118 to 92/min.

Rationale: When volume is restored, the kidneys receive more blood flow and make more urine, and the heart no longer has to beat fast to keep up the blood pressure. A rising urine output and a falling heart rate are signs that fluid replacement is working (C). The nurse also looks for a steady blood pressure, moist mucous membranes, improving mental status and no signs of overload, such as crackles. Option A is wrong because a rising specific gravity means the urine is becoming more concentrated, which points to an ongoing deficit. Option B is wrong because a rising hematocrit suggests hemoconcentration, which also happens when the blood has too little water. Option D is wrong because weight loss suggests the client is still losing fluid; with successful replacement, the weight usually goes up toward the client's usual weight.

Answer: B. A 79-year-old who takes furosemide, has had a fever of 39°C (102.2°F), and has eaten and drunk very little for 3 days.

Rationale: This client has several risk factors for fluid volume deficit at the same time (B). Older adults have less total body water and a weaker thirst response. A loop diuretic increases fluid loss through the kidneys, fever increases fluid loss through the skin and breathing, and poor intake means the losses are not being replaced. The nurse watches this client closely for orthostatic changes, confusion, low urine output and rising BUN, and talks with the provider about the diuretic and fluid replacement. Option A is wrong because SIADH causes the body to hold on to water, which leads to fluid excess and dilutional hyponatremia. Option C is wrong because a missed dialysis treatment allows fluid to build up, putting the client at risk for fluid excess. Option D is wrong because a client with cirrhosis and ascites already has extra total body fluid and sodium, and IV saline adds to the risk of overload.

Answer: D. Elevate the legs when sitting or in bed, reposition the client regularly, and inspect the skin for breakdown.

Rationale: Edematous skin is stretched, has poor blood flow and breaks down easily. Raising the legs helps fluid return toward the heart, and repositioning on a regular schedule, often at least every 2 hours or as facility policy directs, along with careful skin checks, helps prevent pressure injuries (D). The nurse also keeps the skin clean and dry, avoids tight clothing and follows any orders for compression or diuretics. Leg elevation may need to be adjusted if the client cannot tolerate it, such as when lying flat makes breathing harder. Option A is wrong because firm massage can damage fragile skin and is not an effective treatment for edema. Option B is wrong because letting the legs hang down increases swelling. Option C is wrong because edematous skin has reduced sensation and blood flow, so heat can easily cause burns.

Answer: A. "Offer drinks at regular times through the day, because older adults may not feel thirsty even when they need fluid."

Rationale: The thirst response weakens with age, so older adults can become dehydrated without feeling thirsty. Offering fluids on a schedule, keeping a drink within reach and offering foods with high water content help prevent a deficit (A). The amount each person needs depends on their health, so the family follows any guidance from the provider. Option B is wrong because waiting for thirst can mean fluids are given too late. Option C is wrong because cutting fluids during the day raises the risk of dehydration, constipation, urinary tract infection and confusion; if night-time urination is a problem, the provider may suggest drinking less in the evening, not during the day. Option D is wrong because alcohol increases urine output, and large amounts of caffeine may also add to fluid loss in some people, so water and other non-alcoholic drinks are better choices.

Answer: C. 30 mL of water used to flush the feeding tube and a 100 mL IV antibiotic piggyback.

Rationale: Intake includes all fluid that enters the body: oral fluids and foods that are liquid at room temperature, tube feedings and the water used to flush the tube, IV fluids, IV piggybacks and fluid given with IV medicines, and irrigation fluid that is not returned (C). Leaving out flushes and piggybacks can make intake look much lower than it is. Ice chips are usually recorded at about half their volume, but the nurse follows facility policy. Options A, B and D are wrong because drain output, liquid stool and emesis are all fluid leaving the body, so they are recorded as output. Accurate intake and output, together with daily weights, help the nurse and provider spot fluid volume deficit or excess early.