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Fluid and electrolyte therapy

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Presentation on theme: "Fluid and electrolyte therapy"— Presentation transcript:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

15 Normal maintenance requirements (holiday and segar

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

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

18 Infant: moderately severe dehydration

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

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

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

22 Assessment of deficit severity

23 Assessment of severity: contd

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

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

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

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

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

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

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

31 Commonly available crystalloids: isotonic
Fluids Na (mmol/l) K (mmol/l) Cl (mmol/l) Energy(kcal/l) other saline0.9% 150 saline0.45%dextrose 2.5% 75 100 Saline 0.18% dextrose 4%,KCl 20mmol/lit 30 20 160 Dextrose 5% 200

32 Isotonic crystalloid fluids
Na K Cl Energy Other Saline 0.18% dextrose 4% 30 160 Hartmann’s solution 131 5 111 lactate

33 Hypertonic crystalloids
Fluid Na K Cl Energy Other Saline 0.45% dextrose 5% 75 200 Dextrose 10% 400 Saline 0.18% dextrose 10% 30 Dextrose 20% 800

34 Colloid fluids Fluids Na K Ca Duration of action comments Albumin 4.5%
150 1 6 Protein buffers Gelofusine 154 <1 3 Gelatine Haemaccel 145 5 12.5 Pentastarch 7 Hydroxyethyl starch

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

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

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

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

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

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

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

42 Composition of external losses
Fluid Na (mmol/l) K (mmol/l) Cl (mmol/l) Protein (g/dl) Gastric 20-80 5-20 Small bowel 5-15 90-130 Ileostomy 45-135 3-15 20-115 Diarrhoea 10-90 10-80 10-110 Burns 140 5 110 3-5 Sweat 10-30 3-10 10-35

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

58 Hyperkalemia:management
If cardiac rhythm affected give calcium 1 mmol/kg iv/specific anti arrhythmic drug If normal rhythm, give nebulised salbutamol 2.5 to 5 mg. Check K and pH. If falling K- give calcium resonium 1g/kg po or pr- plan dialysis if needed 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 If pH >7.35 give sodium bicarbonate 2.5 mmol/kg iv

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

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

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

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

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

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

65 Case 2 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. Severe dehydration on examination Blood: Na 136, K 2.2, Hco3 8, pH7.35

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

67 Case 3 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. Moderate dehydration Glucose 30 mmol/l, Na 128 mmol/l, K 4.8 mmol/l, HCO3 8 mmol/l, pH 7.28

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

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

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