Volume and Electrolytes. Fluid and Electrolyte Management. Why 125ml? Question. Normal fluid requirement. Normal losses

Transcription

1 Volume and Electrolytes Fluid and Electrolyte Management Pre-existing deficits of excesses Ongoing losses or gains Ajai K. Malhotra, MD VCU School of Medicine 1 2 Question Why 125ml? Intern said so Chief resident asked me to Attending ordered me to That is the normal requirement 3 4 Normal fluid requirement Normal losses First 10 Kg Second 10 Kg Subsequent Kg per hour 4ml 2ml 1ml per 24 hours 100ml 50ml 25ml Sensible losses urine feces Insensible losses skin lung 5 6 1

2 Sensible losses Minimum urine volume ~400ml normal kidneys maximally concentrating urine Adequate urine volume ½ml/Kg (30ml/hr) higher for children ml Fecal loss ml Total sensible loss = ~ 1800ml 7 Losses Insensible ambient temperature ml Total = sensible + insensible = 2800ml 8 Calculations 24 hour losses = = 3000ml/24hr Formulae (70Kg healthy male) I 10Kg 40ml/hr 1000ml/24hr II 10Kg 20ml/hr 500ml/24hr 50Kg 50ml/hr 1250ml/24hr Total 110ml/hr 2750ml/24hr (2640ml/24hr) Question 9 10 Sodium Fluid and Sodium Sensible losses urine 1500ml ~150mEq fecal 300ml ~30mEq Insensible loss 1000ml ~15-30mEq Formula 2-4mEq/Kg 11 70Kg healthy male fluid volume ~3000ml sodium ~210mEq Fluid needed for normal requirements 210mEq Na+/3L = ~70mEq/L Available fluid ½ NS 77mEq/L 12 2

3 Question? Question? Why D5W? provide caloric needs something is better than nothing required for body to use sodium prevent catabolism why? Protein sparing effect of glucose Question? Other ions Add to fluid as necessary Pre-existing deficits/excesses Ongoing losses/gains Diagnosis clinical Quantification severity of clinical signs Treatment deficit: repletion excess: removal Ongoing monitoring 17 Losses GI urinary post-operative ( third spacing ) increased insensible losses Gains medications catabolism resorption of third space 18 3

4 Sodium Hypo/hyper natremia Sodium concentration determines body fluid osmolality manages water Hypo/hyper natremia reflection of body water status hyponatremia: water excess hypernatremia: water deficit rarely true sodium deficit/excess Hyponatremia Hypernatremia True Δ [Na + ] X TBW (5% NaCl) D5W Spurious Restrict water (3-5% NaCl) D5W Hypo/hyper natremia Initial partial rapid correction alleviate symptoms Rapid total correction is extremely dangerous rapid increase: central myelinolysis rapid decrease: convulsions/coma Close monitoring Potassium Roles neuromuscular communication cardiac function gut motility acid/base regulation Hypokalemia Hyperkalemia post-operative renal failure iatrogenic excessive losses Hyperkalemia Presentation Dangerous Immediate treatment cardioprotection calcium gluconate 1gm as 10% solution encourage cellular uptake dextrose and insulin alkalinization Removal of potassium exchange resins dialysis 23 Hypokalemia Presentation Treatment prevention repletion <20mEq/hr 24 4

5 Calcium Neuromuscular stability Hypo/hyper calcemia presentation Hypocalcemia Pancreatitis massive infection renal failure pancreatic and GI fistula hypoparathyroidism x Hypercalcemia metastatic cancer hyperparathyroidism 25 Hypo/hypercalcemia Hypocalcemia acute IV administration long-term PO calcium + vitamin D Hypercalcemia vigorous diuresis PO or IV phosphates steroids and calcitonin plicamycin 26 Magnesium Essential for most enzyme systems Hypo/hyper magnesemia presentation Hypomagnesemia starvation malabsorption iatrogenic pancreatitis DKA alcoholism Hypermagnesemia renal insufficiency iatrogenic burns massive trauma dehydration acidosis Hypo/hyper magnesemia Hypomagnesemia prevention parenteral administration MgSO 4 or MgCl 2 Hypermagnesemia calcium gluconate: 5-10mEq correct acidosis and dehydration dialysis aldostronism Pre-operative management Correct volume and electrolyte abnormalities external losses internal redistribution Clinical diagnosis separate entities algebric sum Intensive monitoring Intra-operative management Blood replace with blood for blood loss >500ml Fluid requirements (losses) degree of dissection duration of procedure crude guide: ml/hr to max of 2-3L/4hours Intensive monitoring

6 Post-operative third space I phase of healing inflammatory phase capillary leak Quantification degree of dissection Type of loss extra-cellular fluid POD III onwards resorption Early post-operative period (POD I&II) Carryover from surgery Extra losses/gains third space GI medications catabolism Late post-operative period (POD III onwards) Extra losses/gains GI medications resorption of third space Other ion replacements 33 Summary Similar for volume and electrolytes small amount of glucose Pre-existing deficits/excesses Ongoing losses/gains Evaluation clinical and limited laboratory Signs and symptoms algebric sum Monitoring 34 6