Fluid & Elyte Case Discussion. Hooman N IUMS 2013

Transcription

1 Fluid & Elyte Case Discussion Hooman N IUMS 2013

2 Objectives Know maintenance water and electrolyte requirements. Assess hydration status. Determine replacement fluids (oral and iv) Know how to approach to dyskalemia

3 Approach to Fluid Calculations 1. Maintenance: 2. Deficit: 3. Ongoing losses: Determined by a system : a. Caloric expenditure method b. Holliday-Segar method c. Surface area method Determined by acute weight change or clinical estimate Determined by measuring

4 GOAL OF MAINTANANCE FLUIDS Prevent dehydration Prevent electrolyte disorder Prevent ketoacidosis Prevent protein degradation

5 Maintenance Fluids Holliday-Segar Method Estimates caloric expenditure from weight, assuming that for each 100 calories metabolized, 100 ml H 2 0 are required. Body Weight ml/kg/day Water ml/kg/hr First 10 kg Second 10 kg 50 2 Each additional kg 20 1

6 Example: 8 year-old weighing 25kg ml/kg/day 100 (for 1 st 10 kg) x 10 kg = 1000 ml/day 50 (for 2 nd 10 kg) x 10 kg = 500 ml/day 20 (per remaining kg) x 5 kg = 100 ml/day 1600 ml/day

7 Examples A 6 kg child needs 600 ml/day, which equals 25 ml/hr A 35 kg child needs 1800 ml/day,which equals 75 ml/hr A 14 kg child needs 1200 ml fluids with: Na K Cl 36 meq (3 meq/100 cal) 24 meq (2 meq/100 cal) 48 meq (4 meq/100 cal)

8 Maintenance Electrolytes Electrolyte meq/100 ml H 2 O Na + 3 (2-4) K + 2 (2-3) Cl - 4

9 Modifications Increase Fever (12% for each o C above 37 o C ) High ambient temperature Diabetes mellitus Diabetes insipidus Vigorous exercise Decrease Renal failure Heart failure Inappropriate secretion of ADH High-humidity respiratory therapy

10 Acute Renal Failure Meticulous management of fluids and electrolytes is required, including twice daily weights, strict I/O s and close laboratory monitoring Oligo-anuric patients should receive fluid intake equal to their total output; output must include insensible losses Insensible losses should be replaced with D5W (or D10W)

11 Assessing Hydration Status History Volume of liquid intake Frequency of wet diapers/urination Frequency/quantity of diarrhea Recent weight (if known) Labs BMP if admitting the patient Serum sodium

12 Deficit

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16 Tenting

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18 Normal

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20 severe

21 Urine output

22 Vital Sign

23 Sign & Symptoms Mild Moderate Severe Wt loss 3-5% 6-9% >10% General condition Alert, Restless Thirsty, lethargic Cold,sweaty,limp Pulse Normal rate, volume Rapid,weak Rapid,feeble Respiration Nr Deep,rapid Deep,rapid Ant.fontanelle Nr Sunken Very sunken SBP Nr Nr/ low OH Low/ unrecordable Skin turgor Nr Decreased Markedly decreased Eyes Nr Sunken,dry Grossly sunken Mucus membrane Moist Dry Very dry Urine output Adequate Less,dark Oliguria, anuria Capillary refill Nr <2 sec > 3 Sec Estimated deficit 30-50ml/kg 60-90ml/kg 100ml/kg

24 % Dehydration ( PIW IL / PIW ) x100%

25 ECF and ICF Percentage of Loss % fluid of deficit % fluid of deficit Duration of illness from ECF from ICF <3 days >3days 60 40

26 Electrolytes in Body Fluids (meq/l) Na K Cl HCO3 Gastric juice Small-intestinal juice Diarrhea Sweat normal Sweat CF Normal saline ½ Saline Ringer Lactate

27 Third-spaced fluid H: Sequestration of fluid Fluid is isotonic, Check urine output Surgical trauma Type of surgery Fluid replacement Minimal Inguinal hernia repair 1-2 ml/kg/h Moderate Ureteral implantation 4ml/kg/h Severe Scoliosis, bowel obstruction >6ml/kg/h

28 Oral vs. IV Replacement Oral rehydration therapy (ORT) is preferred for mild moderate dehydration unless emesis is intractable stool losses > 10 cc/kg/hr consciousness is impaired

29 IV Emergency Replacement AKA Boluses What fluid? Isotonic fluid 0.9% NS, Lactated Ringers NO dextrose-containing fluids How much fluid? 20 cc/kg over minutes. Patients with congenital heart disease or renal insufficiency - ~10 cc/kg over minutes. How many boluses? Enough (although consider pressors if you re needing more than cc/kg)

30 IV Maintenance Fluids 3 important components Dextrose D 5 for most children; D 10 in the NICU Potassium (except for patients with decreased urine output or renal insufficiency) Usually add 20 meq/l Sodium

31 Common IV Fluids Fluid Na (meq/l) D 5 W 0 0.9% NaCl (NS) % NaCl (1/2 NS) % NaCl (1/4 NS) 34 Lactated Ringers 130

32 ORT

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39 Which fluid do I choose? Consider the patient s daily free water and sodium needs. 5 kg infant FW: 5 kg x 100 cc/kg/day = 500 cc/day Na + : 5 kg x 3 meq/kg = 15 meq/day 15 meq/500 cc = 30 meq/l D NS 20 kg child FW: (10 kg x 100 cc/kg/d) + (10 kg x 50 cc/kg/d) = 1500 cc/day Na + : 20 kg x 3 meq/kg = 60 meq/day 60 meq/1500 cc = 40 meq/l D NS

40 Case 1 A 2 year old has a 4-day history of gastroenteritis, poor fluid intake and infrequent urination. On exam you find dryness of the mucous membranes, sunken eyes with mild tenting of the skin. The serum sodium is 137 meq/l. The weight is 10 kg. You determine the child is suffering from about 10% dehydration. What are the fluid and electrolyte requirements?

41 Isonatremic Dehydration Patient is dehydrated and Na + is meq/l Determine fluid deficit as percentage of weight based on clinical findings Determine which parts of deficit come from ICF versus ECF compartments based on duration of illness ECF Na + loss = ECF Fluid deficit (L) X 145 ICF K+ loss = ICF Fluid deficit (L) X 150

42 Isonatremic Dehydration Maintenance Total deficit = 1000 ml Extracellular fluid deficit (60% of total) Intracellular fluid deficit (40% of total) Total H2O Na K Cl (ml) (meq) (meq) (meq)

43 Phase Approach PHASE 1 Emergency restoration of circulation if patient is hypovolemic ml/kg of isotonic fluids only 40ml/kg No response 10ml/kg albumin/plasma/blood PHASE 2 Replacement of ½ of the fluid loss (deficit and maintenance) in first 8 hours Replacement of ongoing loss PHASE 3 Replacement of remaining ½ of the fluid loss (maintenance and remaining deficit) in next 16 hours Replacement of potassium after voids

44 Case 2 3 m infant Loose watery stools x3days Vomiting X4 during last 12 hours No urine for 10 hours Wt : 5 kg, PR: 160 /min, RR= 60/min BP: 90/85 Fontanels & eye sunken Extremities cold, skin mottled Loss of skin turgor No tear, weak cry Capillary refill time 3 sec Good sensorium

45 Deficit 10%? ml/kg Calculate the first day fluid therapy

46 Wt = 5kg Water Sodium Potassium Maintenance Deficit Ongoing loss

47 case 7 A 7 year old boy presented with at least a weeks history of abdominal pain and vomiting and polyuria. He was mildly confused. BP= Nr., wt=25 kg PH=7.52 Na=137 PCO2=44.6 K= 2.2 HCO3= 38 Cl=91 How do you approach to this patient? How do you treat? What is the cause of hypokalemia?

48 Wt =9 kg Water Sodium Potassium Maintenance Deficit Ongoing loss

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52 Treatment Oral Safest, although solutions may cause diarrhea IV Peripheral: do not exceed meq/l potassium - Avoid temptation to rapidly bolus Central: meq/kg over 1-3 hours, depending on severity Replace magnesium also if low (25-50 mg/kg MgSO 4 )

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56 Case Study #8 HPI: An eight month old infant with autosomal recessive polycystic kidney disease presents with irritability. She is on nightly peritoneal dialysis at home. The lab calls a panic potassium value of 7.1 meq/l. The tech says it is not hemolyzed. What do you do now?

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58 Cardiac Monitor What is this rhythm?

59 What is the immediate treatment? 1- Calcium Gluconate 2- Hypertonic Saline 3- Insulin infusion for 4 H 4- Albuterol inhaler

60 The goals of therapy, in chronologic order 1. Antagonize the effect of K on excitable cell membranes. 2. Redistribute extracellular K into cells. 3. Enhance elimination of K from the body.

61 Rapid treatment

62 Elimination Clin J Am Soc Nephrol 5: , 2010 J Am Soc Nephrol 21: , 2010.

63 After infusing calcium gluconate, ECG showed sinus rhythm, what is the next step of therapy? 1- Sodium Bicarbonate 2- Furosemide 3- hemodialysis 4- peritoneal dialysis 5- Kayexelate

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66 Any Question?