Fluid resuscitation — balanced crystalloid, responsiveness and the SMART evidence

Fluid choice (5 marks). Default is a balanced crystalloid (Hartmanns/Plasma-Lyte). SMART showed balanced crystalloids reduce major adverse kidney events versus saline in critically ill adults; large saline loads cause hyperchloraemic metabolic acidosis and renal vasoconstriction. Early sepsis boluses are given in 250–500 mL aliquots toward a working ~30 mL/kg rescue while starting source control and antibiotics, with early noradrenaline if profound vasoplegia.^[1]

Responsiveness (5 marks). Only about half of unstable patients are fluid-responsive (56 per cent in pooled dynamic-test data). I use passive leg raise from the semi-recumbent position (best dynamic test in spontaneous breathing), pulse-pressure variation if fully adapted on controlled ventilation, IVC variability with caveats, and clinical endpoints (MAP, lactate trend, urine output, capillary refill). I stop boluses when non-responsive to avoid oedema harm.^[4][5]

Caveats (5 marks). Hydroxyethyl starch is abandoned (CHEST/6S — more AKI/RRT, no mortality benefit). Albumin is harmful in TBI (SAFE-TBI higher mortality) — never give albumin to the head-injured. In bleeding trauma minimise crystalloid, give blood products and use permissive hypotension when appropriate (delayed fluids improved survival in penetrating torso injury). Saline remains niche (e.g. first-hour DKA sodium need).^[2][3][6][7]