A client with myocardial ischemia is having frequent PVCs.
Which medication will the nurse administer?

Choice A rationale

Gentamicin is an aminoglycoside antibiotic known for its significant nephrotoxic and ototoxic side effects. In a patient with acute renal failure, the clearance of gentamicin is severely impaired because it is primarily excreted unchanged by the kidneys. Normal serum creatinine is 0.7 to 1.3 mg/dL. Administering a standard dose to a patient with failing kidneys can lead to toxic accumulation, further worsening renal damage. The nurse must verify dose adjustments or alternative therapies with the provider.

Choice B rationale

Sucralfate is a mucosal protectant used to prevent stress ulcers in mechanically ventilated patients. It works locally by forming a protective barrier over gastric erosions and does not require significant renal clearance or systemic absorption. While it can interfere with the absorption of other drugs, it is generally considered safe for patients with renal failure. It is a standard prophylactic measure in the intensive care unit to prevent gastrointestinal bleeding during periods of physiological stress like ARDS.

Choice C rationale

Ranitidine is an H2-receptor antagonist used to reduce gastric acid secretion and prevent stress-induced gastritis. While some dose adjustment may be necessary in severe renal impairment, it does not possess the high level of acute nephrotoxicity seen with aminoglycosides. It is frequently used in critically ill patients to maintain a gastric pH above 4.0. Its use in this patient is common practice, and while monitoring is required, it does not pose the immediate threat that gentamicin does.

Choice D rationale

Methylprednisolone is a corticosteroid used in the fibroproliferative phase of ARDS to reduce pulmonary inflammation and improve oxygenation. It is metabolized primarily by the liver rather than the kidneys. Therefore, acute renal failure does not significantly alter its clearance or increase the risk of acute toxicity in the same manner as renally excreted antibiotics. It is a vital component of the inflammatory management for ARDS and would not typically require an urgent consultation.

Choice A rationale

The standard recommendation for crystalloid fluid resuscitation in hypovolemic shock is the 3 to 1 rule. This means that for every 1 liter of estimated blood or fluid volume lost, 3 liters of crystalloids such as normal saline or Lactated Ringer's should be administered. This ratio accounts for the fact that only about one fourth to one third of the infused isotonic crystalloid remains in the intravascular space, while the rest shifts into the interstitial compartment.

Choice B rationale

Replacing each liter of fluid loss with 5 liters of crystalloid is excessive and increases the risk of severe complications. Over-resuscitation can lead to pulmonary edema, abdominal compartment syndrome, and dilutional coagulopathy. While aggressive fluid therapy is necessary for severe volume loss, the 5 to 1 ratio exceeds standard clinical guidelines and can cause significant fluid overload, placing unnecessary stress on the cardiovascular and renal systems without providing additional benefit for maintaining the effective circulating volume.

Choice C rationale

A 2 to 1 replacement ratio is often insufficient to restore and maintain intravascular volume in the setting of severe fluid loss. Because crystalloids rapidly redistribute from the plasma into the interstitial fluid, a 2 liter infusion would likely result in less than 500 mL remaining in the vessels. This would fail to correct hypovolemia effectively and could lead to persistent tissue hypoxia and organ dysfunction. The 3 to 1 rule ensures more adequate plasma volume expansion.

Choice D rationale

Replacing fluid loss on a 1 to 1 basis with crystalloids is inadequate because crystalloids are not confined to the intravascular space. Unlike blood products or colloids, which have higher oncotic pressure, isotonic saline leaves the capillaries quickly. A 1 to 1 ratio would result in a significant net deficit in circulating volume, failing to stabilize the patient's blood pressure or heart rate. Clinical protocols require the higher 3 to 1 ratio to achieve hemodynamic stability.