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Fluids and Electrolytes. James Zeng. Complicated?. Simple?. Body Compartments. Plasma 3L. Na. K. Interstitial 12L. Intracellular 30L. Extracellular 15L. Replacement. Lost Ongoing losses Maintenance. Sources of Loss. Renal GI Skin Haemorrhage “Third Space”. Basal Fluids. 1.6L.
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Fluids and Electrolytes James Zeng
Body Compartments Plasma 3L Na K Interstitial 12L Intracellular 30L Extracellular 15L
Replacement Lost Ongoing losses Maintenance
Sources of Loss • Renal • GI • Skin • Haemorrhage • “Third Space”
Basal Fluids 1.6L Lungs 400 Urine 500 Stool 200 Skin 500
Basal Electrolytes Na • 2mmol/kg/d (140mmol) K • 1mmol/kg/d (70mmol)
Input Enteral • Oral, NG, stomas Parenteral • IV, subcutaneous
Parenteral Fluids Crystalloids Colloids Larger insoluble molecules High oncotic pressure Albumin, Synthetics (gelofusine, pentastarch), blood • Aqueous solutions • Solutes in water normal saline, 5% dextrose, 4% and 1/5, hartmann’s (CSL)
Simple 25yo male MBA. Weber C # (nothing else) Theatre some time tomorrow.
Replacement Lost Ongoing losses Maintenance
A Bit Harder 30yo female. Stabbed a few times. HR120. BP80/60. Conscious. For theatre.
Replacement Lost Ongoing losses Maintenance
Back to the Stabbing Replace! • 2x 16G • 1+1L Stat • Consider blood products
More Complicated 74yo lady LBO Difficult hartmanns x2 PRC intraop Hb90 IHD, diabetic D2 post op UO 15mL Lost Lost
Replacement Lost Ongoing losses Maintenance
Whoa! • Is she dry? • If dry, how much? • How do I give it? • Monitoring?
History Dry Wet SOB SOA Distension Thirst Weakness Dizziness
Exam Look at the chart, fasting status. Arterial (dry) • Hr, bp (postural), urine output trend, GCS Venous (wet) • JVP, Chest, ascites, oedema
Tests? • Not really useful acutely • Worth doing for monitoring
So What Do I Do? • Is she dry? • If dry, how much? • How do I give it? • Monitoring? It Depends!
Dry? Maintenance • 1.5L/d Lost • ~1L Blood, probably replaced • Correct any imbalances, estimate hydration status Ongoing • Probably increased in third space
Wet? Poor renal perfusion • Pump failure, sepsis, drugs Renal • Drugs, ATN, GN Post renal
Hyponatraemia Dry Wet (or normal) Inappropriate free water retention SIADH (central, peripheral) Cirrhosis CCF Restrict fluid Treat cause • Excessive loss of sodium containing fluids • Renal, GI, skin • Give slow replacement
Hypernatraemia Dry (or normal) Wet Inappropriate sodium retention Hyperaldosteronism (adenoma, poor perfusion, low oncotic pressure) Renal failure Treat cause • Excess free water loss • Diabetes insipidus (central or peripheral) • Loss from GI and skin • Replace free water
Hyperkalaemia Shift from cells • Acidosis, Rhabdo, tumour lysis Inappropriate retention • Hypoaldosterone, addisons, drugs Fatal arrythmias • Small P, tented Ts, sinusoidal rhythm
Hyperkalaemia • Ca carbonate 10mL 10% centrally • Insulin 10U (50ml 50% dextrose) • Bicarb • Salbutamol • Risonium • Dialysis
Hypokalaemia • Usually lost somewhere (GI, renal) or redistributed (alkalosis) • Replacement (oral or IV) • Also replace Mg