A nurse is assisting a client with ambulation several hours after a hip replacement. Which of the following postoperative complications is the nurse trying to prevent?

A. "Vaccines are recommended so that medicines such as antihypertensives will not be necessary.": Vaccinations provide immunological protection against specific infectious pathogens and do not influence the physiological mechanisms of systemic blood pressure. Antihypertensive medications treat cardiovascular pathology, which is unrelated to the biological response elicited by viral or bacterial immunizations. There is no clinical evidence linking vaccination to the prevention of primary hypertension.

B. "Vaccinations are recommended because they help your body glow and improve your skin tone.": The primary objective of immunization is the induction of adaptive immunity to prevent communicable diseases, not aesthetic enhancement of the integumentary system. While overall health contributes to skin appearance, "glowing" is not a scientific or medical indication for vaccine administration. This statement utilizes non-medical terminology that misrepresents the clinical purpose of vaccines.

C. "Vaccinations protect you from serious diseases and help prevent the spread of illness to others.": Vaccines stimulate the production of antibodies and memory cells, providing individual immunity against debilitating or fatal infections. Furthermore, high vaccination rates contribute to herd immunity, reducing the reservoir of pathogens available to infect vulnerable populations. This dual benefit of personal and public health protection is the scientific cornerstone of immunization.

D. "Vaccinations are recommended mainly to treat illnesses after you get sick.": Immunizations are prophylactic interventions designed to prime the immune system before exposure to a pathogen occurs. They are not curative treatments for active, symptomatic infections, which instead require antibiotics, antivirals, or supportive care. Administering a vaccine after the onset of disease does not serve as a primary therapeutic modality.

A. The oliguric phase lasts for 2 days.: The duration of this phase is typically 10 to 14 days, though it can persist for several weeks. A 2-day timeframe is insufficient for the significant renal parenchymal recovery required to transition to the diuretic phase. Prolonged oliguria is associated with a poorer prognosis for the restoration of baseline renal function.

B. The oliguric phase begins within 1 month of the injury.: This phase typically manifests within 1 to 7 days of the initial insulting event to the kidneys. A delay of 1 month would be inconsistent with the clinical progression of acute kidney injury. Rapid onset of decreased urine output is a hallmark of early stage renal tubular compromise.

C. The client's urine output is less than 400 mL per 24 hours.: Oliguria is clinically defined as a total daily urine volume insufficient to excrete metabolic waste products effectively. This reduction in output results from a severely diminished glomerular filtration rate and cast formation obstructing the renal tubules. Monitoring for this specific volume threshold is essential for diagnosing the severity of the injury.

D. The client's BUN and creatinine decreases during this phase.: Blood urea nitrogen and serum creatinine levels rise significantly during the oliguric phase due to the lack of renal clearance. The accumulation of these nitrogenous wastes leads to the clinical syndrome of uremia. Decreasing levels are only expected once the client enters the recovery phase of the disease.