Which of the following BEST describes the Starling forces that govern transcapillary fluid movement in the context of oedema formation after large-volume crystalloid infusion?

• A Reduced capillary hydrostatic pressure increases interstitial oedema by lowering the absorption gradient
• B Plasma oncotic pressure is the sole determinant of oedema; capillary pressure plays no role
• C Increased capillary hydrostatic pressure and reduced plasma oncotic pressure both favour fluid movement into the interstitium ✓
• D Lymphatic flow decreases after crystalloid infusion, causing oedema independently of Starling forces

Explanation

Starling forces governing transcapillary flux are: filtration = Kf [(Pc − Pi) − σ(πc − πi)], where Pc is capillary hydrostatic pressure, Pi is interstitial pressure, πc is plasma oncotic pressure, and πi is interstitial oncotic pressure. Large-volume crystalloid infusion raises capillary hydrostatic pressure (Pc) and simultaneously dilutes plasma proteins, reducing colloid oncotic pressure (πc). Both changes increase net fluid filtration into the interstitium, causing oedema. This is the principal reason excessive crystalloid resuscitation leads to tissue oedema, impaired wound healing, and gut oedema. Balanced crystalloids and albumin solutions partially mitigate these effects.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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