Editing Open Kidney Surgery (section)

==== Preoperative considerations ====
* '''Hyperfiltration injury:''' when a significant portion of renal parenchyma is removed, the renal blood flow is delivered to a smaller number of nephrons, which can lead to increased glomerular capillary perfusion pressure that results in an increased single-nephron glomerular filtration rate called hyperfiltration. Over decades, the hyperfiltration can injure the remaining nephrons, resulting in focal segmental glomerulosclerosis and the clinical manifestations of proteinuria and progressive renal failure.
* '''Renal ischemia and hypothermia:''' To minimize blood loss and allow for adequate surgical visibility, it is often necessary to employ vascular compression during partial nephrectomy. Manual and clamp compression of renal parenchyma is preferable, since vascular clamping is associated with a higher incidence of renal complications. '''It is unclear whether leaving the renal vein unclamped for retrograde renal perfusion offers any tangible benefit. Attempting to limit warm ischemia to 20 minutes and cold ischemia to 35 minutes helps maintain renal function'''
* Adequate renal hypothermia (core renal temperature of 20° C) takes at least 15 minutes to achieve if the kidney is packed with ice slush. To help prevent acute postoperative renal failure, intravenous mannitol (12.5 g) and furosemide (20 mg) should be infused about 15 minutes before renal artery clamping. While evidence supporting this practice is somewhat limited, both drugs are quite well tolerated in a well-hydrated patient§§
** '''Intravenous mannitol helps prevent tissue damage by preventing cellular edema.'''