[Verse 1] An obese patient on the table, oxygen debt comes fast Reduced FRC means the reservoir just cannot last Fat compresses diaphragm, compliance starts to fall Less gas stored in the alveoli — apnea takes it all A lean body holds a buffer, minutes till the dip But extra mass cuts margin thin, watch the saturation slip Pre-oxygenate with diligence, buy every second earned Denitrogenate the lungs — that's the first lesson learned [Chorus] FRC is the fortress, autoregulation holds the gate Pressure-volume loops will tell you everything about the state Obesity compresses, aortic lesions narrow down the lane Propofol preserves the curve, volatiles shift the terrain FRC — the fortress, loops — the map, cerebral flow — the refrain [Verse 2] Now draw the loop for normal hearts — an elegant ellipse Wide stroke volume, low end-diastolic, nothing amiss But aortic stenosis warps the geometry entire The outflow tract is throttled so the pressure climbs up higher The loop grows tall and narrow, like a column under stress Concentric hypertrophy compensates — the ventricle's distress Steeper slope on isovolumic contraction, slower to relax The stenotic loop is viscid — thickened walls, restricted tracts [Chorus] FRC is the fortress, autoregulation holds the gate Pressure-volume loops will tell you everything about the state Obesity compresses, aortic lesions narrow down the lane Propofol preserves the curve, volatiles shift the terrain FRC — the fortress, loops — the map, cerebral flow — the refrain [Verse 3] Cerebral autoregulation — MAP from fifty up to one-fifty Constant flow through that plateau, the vasculature is thrifty Volatile agents blunt the curve, dose-dependent vasodilation They uncouple flow from metabolism — pressure drives perfusion Propofol keeps autoregulation largely still intact Cerebrovascular resistance bends but doesn't fully crack When ICP is elevated, choose your agent with precision Volatile or intravenous — that's a consequential decision [Bridge] Here's a word for your lexicon — lambent, meaning softly bright The way autoregulation glows when everything runs right A lambent homeostasis, smooth and barely visible Until the anesthetic breaks it, then the pressure's indivisible Stenotic loops go tall, obese patients drop in seconds flat Propofol protects the plateau — commit that to your format [Chorus] FRC is the fortress, autoregulation holds the gate Pressure-volume loops will tell you everything about the state Obesity compresses, aortic lesions narrow down the lane Propofol preserves the curve, volatiles shift the terrain FRC — the fortress, loops — the map, cerebral flow — the refrain [Outro] Reduced reserve, a narrow valve, a curve that starts to bend Three concepts woven into practice — know them end to end The obese airway, the stenotic squeeze, the cerebral plateau's span Assess yourself against the physiology — that's how you build your plan
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