An infаnt hаs аn acute respiratоry decоmpensatiоn associated with sepsis on DOL 7. The VS are as follows: HR 158, RR (on HFJV), and BP 26/15 (20). Pulses +1/4, capillary refill 4 seconds. The urine output is decreased to 0.5 ml/kg/hr. Urinalysis does not show hematuria or proteinuria. The infant is given a normal saline bolus 10 ml/kg and started on dopamine at 5 mcg/kg/hr and the urine output improves to 1.5 ml/kg/hr. The most likely etiology of this type of acute kidney injury is: A newborn with sepsis has hypotension, delayed capillary refill, and low urine output. After circulatory support, perfusion improves and urine output increases. Which mechanism most likely contributed to the initial oliguria?