1. Quen Mok Great Ormond Street Hospital

2. Chloride: Queen of electrolytes?

3. Predominantly excreted by the kidneys 99% reabsorbed 60% passively in proximal tubules following active sodium transport 15-25% in loop of Henle 5% in distal tubule - aldosterone Renal handling of Chloride

4. Renal excretion of Chloride

5. Hyperchloremic acidosis So why is hyperchloremia a problem? Immune activation and pro-inflammatory Renal dysfunction – renal vasoconstriction and decreased GFR Clotting abnormalities Increased mortality

8. Hyperchloremic acidosis Infusions of 0.9% Saline and Plasmalyte on renal blood flow velocity and renal cortical tissue perfusion Chowdhury AH et al Ann Surg 2012;256:18-24

9. Chloride rich solutions Serum chloride 97-110 mmol/l 0.9% saline – 154 mmol/l chloride 4.5% Albumin – up to 160 mmol/l chloride Hence large volumes potentiate metabolic acidosis regardless of the underlying disease process Often unrecognised and poorly managed Misdiagnosed as inadequate perfusion Base deficit used as a key prognostic variable in paediatric mortality risk score

13. Stewart approach Plasma pH determined by Strong ion difference (SID) – difference between strong cations (Na, K, Ca, Mg) and strong anions (Cl and lactate) PaCO2 Weak acids (A tot ) – mainly albumin and inorganic phosphate Decreased SID has acidifying effect as changes degree of water dissociation into hydrogen ions

14. Strong ion difference

16. Electrolyte composition of common IV fluids CationsAnionsOsm NaKCaMgClAcetateLactateGluconatemosmol /l Plasma135-1453.5-5.04.4-5.21.6-2.498-106Bicarbonate 21-30280-300 NaCl1540 Ringer lactate 1304.03.010928273 Ringer acetate 1304.0 2.011030277 Hartmann ’s 1315.04.011129278 Plasma- lyte 1405.003.0982723295

17. Dialysis Replacement solutions All contain high chloride levels (108-125 mmol/l) Lower if potassium free bicarbonate solutions Serum electrolytes equilibrate with replacement fluid

18. Chloride is a major strong anion in the extracellular fluid space Hyperchloremic acidosis causes renal vasoconstriction and decreased GFR May be misinterpreted as inadequate tissue perfusion Consider use of balanced solutions Serum electrolyte equilibrate with dialysis replacement fluid Conclusions

19. Not the case with chloride…….