Autoregulation breakthrough and glomerular hypertension

Push renal perfusion past the autoregulatory ceiling and the plateau breaks: once the afferent arteriole saturates near 195 mmHg, GFR and glomerular pressure climb with pressure (to 275 mL/min and 66 mmHg at 240 mmHg) — a glomerular-barotrauma surrogate. Inside 80–180 mmHg GFR stays flat. Grade [V]; autoregulation range [L].

Extending the perfusion sweep past the plateau, the afferent resistance hits its ceiling and autoregulation can no longer buffer pressure. Beyond a breakthrough near 195 mmHg, GFR and glomerular capillary pressure rise with perfusion — the surrogate for hypertensive glomerular injury — emerging from the same feedback used for the healthy plateau.

When the afferent arteriole runs out of room

Renal autoregulation flattens GFR by constricting the afferent arteriole as pressure rises, but the arteriole has a maximum resistance. Below the ceiling the plateau holds; above it the controller is saturated and pressure passes straight through to the glomerulus.

Breakthrough and barotrauma

Across 80–180 mmHg GFR is flat (the §4 plateau). Past a breakthrough pressure of about 195 mmHg the afferent resistance is pinned at its ceiling, and GFR and glomerular capillary pressure both climb — reaching 275 mL/min and 66 mmHg by 240 mmHg. This is a mechanistic surrogate for the glomerular hypertension and barotrauma of severe systemic hypertension, and it is not a new rule: it falls out of the same tubuloglomerular-feedback block once its actuator saturates. The autoregulatory window itself (~80–180 mmHg) is the cited anchor [L].