Neonatal Nurse Practitioner Practice Exam

What should be expected in a prerenal oliguria case after administering a test dose of isotonic solution?

1. Decrease in urine output

2. Increase in urine output

3. Remain unchanged

The correct answer is: Increase in urine output

In cases of prerenal oliguria, which is primarily caused by inadequate renal perfusion often due to factors such as dehydration, heart failure, or hypotension, the administration of an isotonic solution serves to restore circulating blood volume and enhance renal blood flow. When a test dose of isotonic solution is given, the kidneys respond by increasing their perfusion, leading to improved glomerular filtration rate. As the renal perfusion improves following the administration of isotonic fluids, one should expect to observe an increase in urine output. This response indicates that the kidneys are adequately rehydrated and are functioning properly to excrete waste products. Therefore, an increase in urine output aligns with the physiological reactions expected when addressing prerenal causes of oliguria with fluid resuscitation.