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1 Fluid and electrolyte therapy Dr Ashoka Acharya Consultant Paediatrics Warwick hospital.

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Presentation on theme: "1 Fluid and electrolyte therapy Dr Ashoka Acharya Consultant Paediatrics Warwick hospital."— Presentation transcript:

1 1 Fluid and electrolyte therapy Dr Ashoka Acharya Consultant Paediatrics Warwick hospital

2 2 Dehydration n Abnormal fluid losses overcoming renal compensating mechanisms n Main aim of compensation is maintaining plasma volume and BP at all cost n Loss of homeostasis –hypovolaemic shock n Principal causes: diarrhoea and DKA

3 3 Definition n Parenteral or oral fluid therapy n Maintain/restore volume/composition of body fluids n Takes account of corrective physiological mechanisms

4 4 Fluid therapy: Goal n Achieve normal intracellular and extracellular chemical environment n Thereby optimise cell and organ function

5 5 Factors determining requirements n Maintenance fluid: replaces usual losses of fluid and electrolytes n Deficit replacement fluid: designed to replace abnormal losses due to disease n Supplemental fluid: replaces measured or estimated continuing abnormal losses

6 6 Factors determining requirements n Each component is calculated separately n Fluid therapy often based on gross estimates. Deficit often overestimated. n Repeated clinical reassessment and adjustment needed

7 7 Maintenance fluid n Directly related to metabolic rate n endogenous water production n urinary solute excretion, n heat production- 25% lost through insensible water loss)

8 8 Maintenance therapy n Generally 100ml per 100 calories used n Urine: obligatory loss = 65 ml n Insensible water loss = 35 ml < Sweating =23 ml < pulmonary =12 ml

9 9 Maintenance therapy: increased requirements n Increased activity (30%) n Fever (1°C increases by 12%) n Dry environment n Hyperventilation n ELBW- transcutaneous losses ml/kg/day n Overhead heaters, phototherapy units

10 10 Maintenance fluid-decreased requirements n Comatose n Hypothermia n Highly humidified atmospheres n Humidified ventilator circuits

11 11 Maintenance fluid: increased renal losses n High solute load (DM, Mannitol, high protein diets) n ADH insufficiency < Central < Nephrogenic H Primary H Secondary: sickle cell, obstructive uropathy, chronic PN, reflux nehropathy, hypokalemia, hypercalcemia, drugs, psychogenic polydipsia

12 12 Maintenance fluid: decreased urinary losses n SIADH n Renal failure v Replace insensible water loss +urine output ml/ml with free water

13 13 Maintenance sodium needs n Increased: CF, salt losing nephropathy, chronic PN, obstructive uropathy, diuretics, fistulas, diversions, NG drainage n Decreased: Hepatic failure, cardiac failure, renal failure, nephrotic syndrome

14 14 Maintenance potassium needs n Increased: Chronic renal disease, gastric and intestinal drainage, chronic diuretics, laxative abuse n Decreased or nil: Acute renal failure, adrenal insufficiency, severe metabolic acidosis

15 15 Normal maintenance requirements (holiday and segar

16 16 Maintenance fluids: route n Oral or parenteral n Calories: usually as 5% dextrose n TPN

17 17 Deficit Therapy: factors affecting n Oral or parenteral intake n Pathologic body losses n Physiologic body losses n compensatory attempts to modify volume and composition è Net effect- Deficits from different causes often similar in magnitude and composition

18 18 Infant: moderately severe dehydration

19 19 Deficit therapy n Severity: Magnitude and rapidity X Estimated from recent weight or clinical features n Type: Relative loss of water and electrolytes mainly sodium < pathophysiology < therapy < prognosis

20 20 Deficit therapy: Types n Isotonic: sodium mmol/l, no fluid shifts, 80% of cases n Hypotonic: sodium <130mmol/l, ECF to ICF, 10% cases n hypertonic:sodium>150 mmol/l, ICF to ECF, 10% cases

21 21 Deficit Therapy:types and history n D and V for days, good intake, low salt n Cholera, bacillary dysentery n High fever, poor intake n Infant with NDI, poor water intake n Intake of dilute milk formula n Intake of boiled semiskimmed milk n wrongly prepared ORS

22 22 Assessment of deficit severity

23 23 Assessment of severity: contd

24 24 Calculation of deficit fluid n Percentage dehydration x wt in kg x 10= ml of fluid n eg: 7% dehydration of infant weighing 10 kgs = 7x10x10=700 ml

25 25 Clinical features n Signs represent depletion of ECF J Plasma: tachycardia, fall of BP, postural hypotension, cool extremities, increased CRT, decreased urine J Interstitial fluid: Tenting of skin J Transcellular fluid: dry mouth, sunken eyes, decreased tears, sunken fontanel

26 26 Signs of dehydration n Mild dehydration: no signs n Severe dehydration: Prolonged capillary refill time,dry mucosa, decreased skin turgor, general appearance are the most sensitive and specific D Acidosis: Kussmauls breathing D Hypokalemia: weakness, abd dist, ileus,cardiac arrhythmias D hypocalcemia and magnesemia: tetany, muscle twitching

27 27 Signs V's type of deficit n Hyponatremic: increased severity of signs for amount of fluid loss n Hypernatremic: Less signs, irritable, hypertonic, hyperreflexic, warm extremities, doughy skin

28 28 Lab tests n FBC: Increased Hb, PCV n Serum Na: type of dehydration n serum K: gut loss, acidosis; needs ECG monitoring n Serum HCO3: acidosis- D&V, DKA: alkalosis-Pyloric stenosis, NG drainage n Serum chloride: changes with Na, chloride diarrhea n Urea/creatinine: elevated with decrease in GFR, may be normal! n Urine: infection screen, specific gravity, electrolytes n stool: culture, electrolytes

29 29 Treatment n Oral therapy: mild to moderate dehydration n Parenteral therapy: severe dehydration Persistent vomiting Refusal of oral intake Abdominal distension No caregiver to give close attention

30 30 Stages of treatment n Initial therapy: expand ECF volume n Subsequent therapy: replace deficit/maintenance/ongoing losses n Final therapy: Return to normal composition/establish oral feeds/correct potassium deficit

31 31 Commonly available crystalloids: isotonic FluidsNa (mmol/l)K (mmol/l)Cl (mmol/l)Energy(kcal /l) other saline0.9% saline0.45 %dextrose 2.5% Saline 0.18% dextrose 4%,KCl 20mmol/lit Dextrose 5%

32 32 Isotonic crystalloid fluids FluidNaKClEnergyOther Saline 0.18% dextrose 4% Hartman ns solution lactate

33 33 Hypertonic crystalloids FluidNaKClEnergyOther Saline 0.45% dextrose 5% Dextrose 10% Saline 0.18% dextrose 10% Dextrose 20%

34 34 Colloid fluids FluidsNaKCaDuration of action comments Albumin 4.5% Protein buffers Gelofusine154<1 3Gelatine Haemaccel Gelatine Pentastarch154007Hydroxyethyl starch

35 35 Initial therapy n Normal saline or Hartmans solution regardless of type of deficit n 20 ml/kg rapid bolus, repeat if needed n IV, intraosseous line Never use hyponatremic fluids Adequate crystalloid dose better than colloid No potassium till urine output established

36 36 Subsequent therapy n Calculate over 8 hour intervals n Deficit replaced over 24 hours but can be done over 8 to 12 hours except HYPERNATREMIA n Early K+ replacement after urine output n Maximum K+, 40 mmol/l (ITU 80 mmol/l)

37 37 Isonatremic dehydration n Deficit plus maintenance plus ongoing losses calculated n Use 0.45%saline with 2.5% or 5% dextrose for subsequent therapy n Give 50% in first 8 hours and remaining over 16 hours n Subtract boluses from total fluid n Assess clinical state regularly and modify if needed

38 38 Hyponatremic dehydration n Extra Na deficit (mmol/l)=desired Na- actual Na x 0.6 x Wt kgs n Manage as for isonatremic dehydration but replace deficit Na over hours n Raise serum Na by 10 mmol/l/day n If Na <120mmol/l and seizures give 3% Nacl 1ml/min max 12ml/Kg

39 39 Hypernatremic dehydration: complications n Cerebral haemorrhage, thrombosis, subdural effusion- permanent handicap, renal vein thrombosis n During treatment- cerebral oedema, seizures, hypocalcemia n High mortality if Serum Na >160mmol/l

40 40 Hypernatremic dehydration n Always use isonatremic boluses n Slow correction of deficit over 48 to 72 hours n Aim to decrease serum Na by 10 mmol/l/day n Use 0.18saline or 0.45% saline with dextrose for subsequent therapy n Seizures: 3% saline, mannitol, hyperventilation, calcium gluconate

41 41 Supplemental fluids n Consider composition of fluid lost n D&V: 0.45% saline n Cholera:0.9% saline n NG tube aspiration: 0.45 to 0.9% saline plus potassium n Gut losses: same

42 42 Composition of external losses FluidNa (mmol/l)K (mmol/l)Cl (mmol/l)Protein (g/dl) Gastric Small bowel Ileostomy Diarrhoea Burns Sweat

43 43 Assessment of response n Appearance, activity n Skin turgor n BP n Intake/output chart n U&E, glucose n blood gas n CVP monitoring n Eyeballs, tears n CRT n Weight n Urine Specific gravity n Urine output n ECG monitoring

44 44 Oral rehydration therapy n Mild to moderate dehydration n Types of ORS: high sodium- 90mmol/l, low Na- 50 mmol/l Glucose facilitated sodium absorption, sucrose less effective, rice based effective

45 45 ORS n Use 50ml/kg in mild and 100ml/kg in moderate dehydration. n Give over 4 hours. Allow breast feeds and formula after rehydration. Reassess regularly. Small frequent feeds decrease vomiting. Consider NG tube. n Maintenance with 100ml/kg/day till diarrhoea stops n For on going losses add 10-15ml/kg/hr

46 46 Hyponatremia: sodium depletion n Renal losses: Preterm, ATN, Diuretics, mineralocorticoid deficiency, RTA n Extra renal loss: D&V, Burns, ascites, pleural effusion,csf drainage, NG drainage, CF n Nutritional deficits: Inadequate Na in TPN, oral intake

47 47 Hyponatremia: water excess n SIADH n Glucocotricoid deficiency n Hypothyroidism n Excess parenteral fluid n Psychogenic polydipsia n Tap water enema

48 48 Hyponatremia: excess Na and water n Nephrotic syndrome n Cirrhosis n Cardiac failure n Acute and chronic renal failure

49 49 Hyponatremia: asymptomatic n Water Excess: (urinary Na usually >20 mmol/l) fluid restriction, may be needed for days n Salt deficiency: (urinary Na <10 mmol/l, except in renal salt loss) Add salt to diet

50 50 Hypernatremia: sodium excess n Improperly mixed ORS or formula n Accidental or deliberate swap of salt for sugar in feeds n Excess Bicarb during resus n Hypernatremic enemas n Drugs: penicillin, gaviscon

51 51 Hypernatremia: water deficit n Diabetes insipidus n Solute diuresis n D&V n Inadequate breast feeds n Intentional water with holding n Insensible loss in prematures

52 52 Hypernatremia: treatment n Salt poisoning: peritoneal dialysis n Phenobarbitone for seizures n Inotropes for heart failure

53 53 Hypokalemia: causes n Diarrhoea n Alkalosis n Volume depletion n Primary hyperaldosteronism,cushing syn, thyrotoxicosis n Diuretic abuse n DKA n Bartters syndrome

54 54 Hypokalemia: consequences n Cardiac: flat T wave and prolonged QT interval n Orthostatic hypotension, tetany, hypotonia, muscle weakness, death from resp failure n Paralytic ileus, gastric distension n Failure to thrive n Rhabdomyolysis n Nephrosclerosis and interstitial fibrosis: polyuria n alkalosis

55 55 Hypokalemia: treatment n Replacement potassium orally or parenterally n 3 mmol/kg/day in Bartter syn/indomethacin n Up to 10 mmol/kg/day in RTA/hyperaldosteronism

56 56 Hyperkalemia: causes n Renal failure n Acidosis n Adrenal insufficiency n Cell lysis (trauma, surgery, tumour lysis) n Excessive intake n Sampling error!

57 57 Hyperkalemia: consequences n Paresthesias, flaccid paralysis n Tall T waves, increased P-R interval, wide QRS complex, VF

58 58 Hyperkalemia:management n If cardiac rhythm affected give calcium 1 mmol/kg iv/specific anti arrhythmic drug n If normal rhythm, give nebulised salbutamol 2.5 to 5 mg. Check K and pH. n If falling K- give calcium resonium 1g/kg po or pr- plan dialysis if needed n If still high (6.5 or more) give dextrose infusion 0.5g/kg/hr and iv insulin infusion, 0.05units/kg/hr if pH <7.34 n If pH >7.35 give sodium bicarbonate 2.5 mmol/kg iv

59 59 Hypocalcemia n Septicemia, rickets,hypoparathyroidsm, pancreatitis, massive blood transfusion, renal failure n Weakness, tetany, convulsions, hypotension and arrhythmias n Calcium infusion, phosphate binders/dialysis, treatment of cause

60 60 Hypercalcemia n Hyperparathyroidism, Hypervitaminosis D&A, Idiopathic hypercalcemia, malignancy thiazide diuretic abuse,skeletal disorders,immobilisation n Polyuria, polydypsia n Volume expansion with saline, treatment of cause

61 61 Hypomagnesemia n Chronic diarrhoea, sprue, celiac d, prolonged TPN low in Mg, hyperaldosteronism, Gitelmans syndrome, cisplatin and aminoglycosides n Convulsions, tetany athetoid movements, hyperaccusis n Im or iv magnesium replacement as magnesium sulphate

62 62 Hypermagnesemia n Usually in renal failure, Addison disease, toxemia of pregnancy, enemas in megacolon n Drowsiness, coma if levels exceed 10 meq/l. Intra ventricular and atrioventricular conduction defects at 5 meq/l n IV calcium gluconate rapidly reverses effects on heart and CNS

63 63 Case 1 n 8 week old infant n Weight 4 kgs, poor wt gain in last 4 weeks, n Vomiting from 3 weeks of age, now after most feeds, forceful, not passing urine well last 24 hours n Moderate dehydration on examination n Na 130, Cl 94, K 2.6, HCo3 29.8

64 64 Case 1 n Maintenance: 100 x 4= 400 ml n On going losses: Ng aspirate volume for volume with normal saline n Start 0.45% saline dextrose 5% to give 400 ml over 8 hours and remaining 400 ml over 16 hours n Add Kcl 4 mmol/100ml once urine output noted n Monitor weight, urine output, Nasogastric aspirate, blood gas and electrolytes,ECG. n Once serum K rises to 3.5 decrease Kcl to 2 mmol/100ml n Deficit fluid: 10 x10 x4= 400 ml n Once stable, send for surgery

65 65 Case 2 n One year old, 10 Kgs with 2 days of D&V. Given clear fluids at home. No urine in last 6 hours. Some fever. Not drinking,lethargic last 2 hours. n Severe dehydration on examination n Blood: Na 136, K 2.2, Hco3 8, pH7.35

66 66 Case 2 n Bolus 20 ml/kg- 0.9%saline, repeat if still shocked n Deficit fluid: 15 x10 x10=1500 ml – 400ml bolus = 1100ml n Maintenance fluid: 100 x10= 1000 ml n Give 1050ml in 8 hours and 1050 remaining in 16 hours as 0.45% saline 5% dextrose n Add Kcl 40 mmol/l after urine output n Monitor ECG, weight, urine output, electrolytes, continuing losses for replacement n Once rehydrated offer ORS, milk and review fluids

67 67 Case 3 n Four year old weighing 14 Kgs, lethargic, vomiting, rapid breathing since 12 hours. Producing urine. Normal stools. Over 2 weeks, since a cold has been drinking a lot, eating a lot and bed wetting again. n Moderate dehydration n Glucose 30 mmol/l, Na 128 mmol/l, K 4.8 mmol/l, HCO3 8 mmol/l, pH 7.28

68 68 Case 3 n Start normal saline infusion, 20 ml/kg over 1 hour n Start insulin infusion 0.05u/kg/hr n 0.45 saline+Kcl 20mmol/500 ml, 20 ml/kg over 2 nd hour n 0.45 saline+KCL or Pot phos 30mmol/l over 10 hours n Maintenance fluid for 36 hours: x4= =1800ml n Deficit fluid: 10x10x14= 1400 ml n Correct 50% deficit in first 12 hours Monitor ECG, glucose, U&E, blood gas, weight, urine output, GCS hourly to 2 hourly n Change fluid to 0.18 saline 5% dextrose when blood glucose reaches 16 to 17 mmol/l. Adjust K and insulin infusion rates as needed. Consider an Antibiotic. n When blood gas normal, blood glucose stable, patient drinking, give subcutaneous insulin 0.2 to 0.4 units/kg qds and stop iv infusions. n Start regular insulin dose after another 24 hours

69 69 DKA: complication n Cerebral edema: headache, change in consciousness,unequal dilated pupil, vomiting,incontinence,delirium,bradycar dia n Reduce iv rate, mannitol 1gm/kg iv, repeat in 2-4 hours

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