1 / 41

Fluids and Electrolytes in Pediatrics

Fluids and Electrolytes in Pediatrics. Kathleen Asas, MD.MPH Inpatient Pediatrics Jan 2011. Objectives. To review basics of maintenance fluid and electrolyte requirements To gain comfort in classification of dehydration and options for fluid support To perform case-based practice!.

ciqala
Download Presentation

Fluids and Electrolytes in Pediatrics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Fluids and Electrolytes in Pediatrics Kathleen Asas, MD.MPH Inpatient Pediatrics Jan 2011

  2. Objectives • To review basics of maintenance fluid and electrolyte requirements • To gain comfort in classification of dehydration and options for fluid support • To perform case-based practice!

  3. Back to Basics….Fluid compartments • Total body water= ICF + ECF • Total body water = 60-75 % of Body weight

  4. Important Concepts • Plasma Osmolality= Concentration of solutes in blood • Plasma Osmolality= 2 x plasma (Na) • Change in plasma osmolality --> change in ECF osmolality with water movement across cell membranes • Remember: The body has an immediate need to restore intravascular volume over osmolality.

  5. Total Body Water Composition by Age

  6. Concepts • Maintenance: Normal ongoing losses of fluids and electrolytes • Deficit: Losses of fluids and electrolytes resulting from an illness • On-going Losses: Requirement of fluids and electrolytes to replace ongoing losses

  7. Factors Increasing Maintenance Fluid Requirements Factors Decreasing Maintenance Fluid Requirements • Fever-each 1 degree Celcius over 38 degrees increases maintenance fluid requirements by 12% • Hyperventilation • Increased temperature of the environment • Burns • Ongoing losses-diarrhea, vomiting, NG tube output • Skin: Mist tent, incubator (premature infants) • Lungs: Humidified ventilator • Mist tent • Renal: Oliguria, anuria • Misc: Hypothyroidism

  8. Goal of Fluid Therapy • To prevent dehydration • To prevent electrolyte abnormalities • To prevent protein degradation • To prevent acidosis and circulatory collapse

  9. Calculation of Maintenance Fluid Requirements…the Holliday-Segar Method Example: A 30-kg child would require (100 × 10) + (50 × 10) + (20 × 10) = 1,700 cc/day or (4 × 10) + (2 × 10) + (1 × 10) = 70 cc/h.

  10. Maintenance Electrolyte Requirements • Na and K are the primary electrolytes that govern ECF and ICF osmolality. [Na] in ECF = 135-145 mEq/L, negligible in ICF [K] in ICF = 150 mEq/L, negligible in ECF • Maintenance Electrolyte Requirements: Na: 2-3 mEq/100ml water /day OR 2-3 mEq/kg/dayK: 1-2 mEq/100ml of water/day OR 1-2mEq/kg/day Chloride: 2 mEq/100ml of water /day

  11. Choosing the Appropriate IVF…let’s practice

  12. Choosing MIVF..these are best estimates… Standard Na content in IVF: • NS (0.9% NaCl) = 154 mEq/l Na • ½ NS (0.45% NaCl) = 77 mEq/l Na • 1/3 NS (0.33% NaCl) = 51 mEq/l Na • ¼ NS (0.25% NaCl) = 39 mEq/l Na • 1/5 NS (0.2% NaCl) = 31 mEq/l Na Standard K content in IVF: 10mEq KCl/L 20 mEq KCl/L 40 mEq KCl/L • 8kg infant: 8kg x 4ml/kg/hr 32 ml/hr Na: 15-30mEq/LK: 8-15 mEq/L D5 ¼ NS + 10meq KCl/L @ 32 ml/hr • Wt-55 kg: Rate 95ml/hr Na: 45-68 mEq/L K: 22-45 mEq/L IVF: D5 ½ NS + 20 mEqKCl/L @ 95ml/hr 3. Wt-80kg: Rate 120ml/hr Na: 57.6-85 mEq/L K: 28.8-58 mEq/L IVF: D5 ½ NS + 20mEq KCl/L @ 120ml/hr

  13. DEHYDRATION….Calculating Deficits

  14. Concepts in Dehydration • Initial loss of fluid from the body depletes the extracellular fluid (ECF). • Gradually, water shifts from the intracellular space to maintain the ECF, and this fluid is lost if dehydration persists. • Acute Illness (<3 days ): 80% of the fluid loss is from the ECF and 20% is from the intracellular fluid (ICF). • Prolonged Illness (> 3 days): 60% fluid loss from ECF and 40% loss from ICF.

  15. Pre-Illness Weight Estimate of Dehydration Scenario 1 (if pre-illness wt known) • Need to accurately monitor patient weights frequently • Fluid deficit (L) = PIW (kg) – IW (kg) (Generally 100cc/kg) • PIW = Pre-illness weight • IW = Illness weight % Dehydration = PIW (kg) – IW (kg) x 100% PIW (kg) Scenario 2: (In ER) • Need illness wt • % DHN based on exam Step 1: Calculate pre-illness wt (PIW): Current wt = PIW wt (1-% DHN) Step 2: Calculate wt loss and respective deficit fluid volume PIW-IW = wt loss Note: 1kg ~ 1000ml fluid deficit Deficit Fluid volume= 100cc/kg wt loss

  16. Maintenance Electrolytes

  17. Oral Rehydration vs IVF…the Big Debate

  18. Oral Rehydration: Key Concepts • Mild to moderate dehydration may be managed successfully with oral rehydration in the majority of cases. • Oral rehydration solutions should contain glucose and sodium in a ratio not to exceed 2:1 • Amount of rehydration solution to be given is based on the estimated percentage of dehydration by weight.

  19. Oral Rehydration • Patient vomiting – 5-10mL Q 5-10 minutes and increase as tolerated • Mild Dehydration – Deficit replacement: 50 mL/kg over 4 hours • Moderate Dehydration – Deficit replacement: 100 mL/kg over 4 hours

  20. Developing a Plan of Action • Determine degree of dehydration • Establish phases (total of 3 phases- Resuscitation, Replacement, and Stabilization)

  21. Phase I: Resuscitation using Isotonic Fluids (NS/LR) at 20ml/kg. Re-evaluation until urine output and dehydration signs improved Phase II: Calculate maintenance & deficit fluid Determine if Isotonic, Hypotonic or Hypertonic Dehydration Hypertonic Na >150 Replace fluids over 48hrs** Hypotonic Na <130 Isotonic 130< Na <150

  22. Phase I – Resuscitation phase • Goal: Restore circulation, re-perfuse brain, kidneys • Mild-Moderate  20 mL/kg bolus given over 30 – 60 minutes • Severe May repeat bolus as needed (ideally up to 60ml/kg) • Fluids – something isotonic such as NS or lactated ringers (LR)

  23. Phase II: Replacement PhasePhase III: Stabilization Phase(For Isotonic/Hypotonic Dehydration) • Goal: Replace deficit of fluids and electrolytes

  24. Hypertonic DehydrationPhase 2: Replacement Phase • Goal: Replace deficit of fluids and electrolytes and daily maintenance • Amount: Deficits + daily maintenance Fluid: • Give over 24-48 hours • IMPORTANT: Lower serum Na by no more than 10-12 mEq/L per day or <0.5mEq/L/hr

  25. Hypertonic Dehydration Phase 3: Stabilization Phase • Goal: Replace ongoing losses and transition towards maintenance therapy • Amount: Replacement + daily maintenance

  26. Exceptions:Severe Hyponatremia • Serum Na < 120, CNS symptoms • Amount of 3# NaCl: (Desired Na-observed Na) x wt x 0.6L/kg 0.5mEq/L • Remember 3% NaCl (0.5mEq Na/ml) • The infusion should be given at a rate to increase the serum sodium by no more than 5 mEq/L/h and is often given more slowly over the course of 3–4 h • Do not replace Na faster than 10-12 meq/L per 24hrs. Why? Central pontine myelinosis: rapid brain cell shrinkage with rapid increase in ECF Na

  27. Steps in Fluid Replacement A. Phase I: Rapid Phase Restore intravascular volume a) Use Isotonic Fluid (NS/LR) b) Replace other components (Ca/glucose) separately based on documented deficit c) Volume: 10-20cc/kg; repeat up to 60cc/kg then re-evaluate B. Phase 2: Replacement Phase Determine type of dehydration based on Na-level (Isotonic, Hypotonic, or Hypertonic) a) Calculate 24-hr water needs Calculate maintenance water Calculate deficit water b) Calculate 24-hr electrolyte needs Calculate maintenance sodium and potassium Calculate deficit sodium and potassium c) Select an appropriate fluid (based on total water and electrolyte needs) Hypotonic and Isotonic Dehydration: Administer ½ calculated fluid during the 1st 8 hrs. Administer remainder over the next 16 hrs. C. Phase 3: Stabilization Replace ongoing losses as they occur (ex: diarrhea) a) Measure every 4-6 hrs and replace with appropriate fluids

  28. Exceptions: Treatment of Hypernatremic Dehydration • Restore intravascular volume. • Determine time for correction based on initial [Na]: [Na] 145-157 mEq/L : 24 hr [Na] 158-170 mEq/L: 48 hr [Na] 171-183 mEq/L: 72 hr [Na] 184-196 mEq/L: 84 hr • Administer fluid at a constant rate over the time for correction Typical fluids: D5¼ NS or D5 ½ NS (with 20mEq/L KCl unless contraindicated) • Follow serum Na • Sodium decreases too rapidly- Increase [Na] of IVF or decrease rate of IVF • Sodium decreased too slowly-Decrease [Na] of IVF or increase rate of IVF ***Lower serum Na by no more than 10-12 mEq/L per day

  29. Take Home Message • Oral rehydration is a safe and effective intervention in patients with mild-to-moderate dehydration who are able to tolerate oral regimen. • Fluid calculations are “best estimates.” Always monitor the effects of your interventions. • Deficit fluid requirements are based on classification of dehydration. • Hypotonic and isotonic dehydration are corrected in 8-hr and 16-hr blocks. • Hypertonic dehydration is corrected based on Na level (usually over 48hrs). • Slow correction of both hyponatremia and hypernatremia.

  30. Let’s Practice!

  31. Case: • A 12 month old male is made NPO for surgery, wt-10 kg. • What would be his maintenance fluid and electrolyte requirement?

  32. Case 1: • Wt: 10kg • Phase 1 (resuscitation): No resuscitation phase required • Phase 2 (replacement): Maintenance Fluid: 10 x 4cc/hr 40ml/hr (or 1000ml/day) • Maintenance Na: 2-3 mEq/100cc fluid 30 mEq Na/LD5 ¼ NS • Maintenance K: 1-2 mEq/100 cc fluid 10 mEq/L KCl • Maintenance fluid choice: D5 ¼ NS + 10mEq KCl/L at 40ml/hr

  33. Case 2 • A 4 year old male presents with a history of vomiting and diarrhea. He has had 10 episodes of vomiting (clear then yellow tinged) and 8 episodes of diarrhea. The diarrhea is now watery and the last few episodes have been red in color. The diarrhea odor is very foul. He feels weak. • Exam: VS T 38.2 degrees (oral), P 110, R45, BP 90/65, oxygen saturation 100% in room air. Wt- 18 kg. • He is alert and cooperative, but not very active. He is not toxic or irritable. His eyes are not sunken. TMs are normal. His oral mucosa is moist but he just vomited. His neck is supple. Tachycardic, Bowel sounds are normoactive. • His overall color is slightly pale, his capillary refill time is 2 seconds over his chest, and his skin turgor feels somewhat diminished.

  34. Questions • Based on clinical criteria, what is his % dehydration? Option 1 (Calculate PIW) 18kg/(1-0.05)= 18.9 (PIW) 18.9kg – 18kg= 0.9 (100ml x 0.9) • What method of fluid administration would you choose? • The parents are insistent on IV fluids. What would be your steps in fluid administration? -Bolus of 20ml/kg -Re-assessment - IVF vs oral rehydration

  35. Oral versus IV rehydration is discussed with his parents who indicate that they have tried oral hydration and are not happy with the results so they would like the IV for him. • An IV is started and a chemistry panel is drawn. • Na 135, K3.4, Cl 99, bicarb 15. • Wt-18kg. • Phase I: resuscitation completed w/NS bolus • Phase II: Determined Isotonic Dehydration Maint fluid: 1400ml Maint Na: 3 mEq/100ml 42 mEq Na/1400ml 30mEq/L Na Maint K: 2 mEq/100ml 28mEq K/1400ml-> 20mEq/L K Deficit fluid in 5% DHN: 18 x 0.05 x 1000-> 900ml -360ml  540ml < 3 days illness; 0.8 (900ml) 720ml (loss from ECF) 0.2 (900lm) 180ml (loss from ICF) Deficit Na: [Na] in ECF × vol deficit [ECF} 135 x 0.720L  97 mEq Na – 55mEq Na (received) 42 mEq Na Deficit K: [K] in ICF x proportion of fluid loss from ICF x deficit 150 x 0.180 L  27 mEq K 1st Phase: NS bolus (360ml, 55mEq Na received) 2nd phase: 1st 8 hr: Replace 1/3 of maintenance Na + H20 + ½ deficit Na and H20: Na: 10 mEq + 21 mEq-> 31mEq/735ml -> 42 mEq Na/L 465ml 270ml K: 7mEq + 14mEq 21mEq/735 28mEq/L K 1st 8hrs: 735 ml of D5 1/3 NS + 25mEq KCl/L @ 92ml/hr Next 16hrs: Replace 2/3 maint Na + H20 AND ½ deficit Na + H20: Na-> 20mEq+ 21mEq-> 41mEq Na/1205 ml 34mEq/L Na D5 1/4 NS K: 26mEq/1205ml 21mEq/L K Next 16hrs: 1205 ml of D5 1/4 NS + 20mEq K/L at 75ml/hr

  36. Question 5: • DR is a 4 year old girl (16kg) who presents to the emergency room with fatigue,headache, generalized malaise, and severe gastrointestinal distress. The ER team gets a chem-7 and discovers her sodium to be 118. They would like to give 3% NaCl and ask you for a recommendation on how much to give, and at what rate.

  37. Answer • Amount of 3# NaCl: (Desired Na-observed Na) x wt x 0.6L/kg 0.5mEq/L • Remember 3% NaCl (0.5mEq Na/ml) • Goal to increase Na by no more than 5mEq/L • Calculation: (125-118) x 16 x 0.6L/kg 134ml of 3% NaCl over 3-4 hrs 0.5 mEq/L

  38. 5kg child with 4-day h/o vomiting/diarrhea, 10% dehydration, [Na] of 128 mEq/L

  39. Determine adequate fluids for 7-kg child with 15%, Na=160

  40. References • Fleisher, G. et al. (2005). Renal and Electrolyte Emergencies. In Cronan, K. & Kost (Eds), Textbook of Pediatric Emergency Medicine. • Kleigman, R. et al. Nelson Essentials of Pediatrics. Chapter 32: Fluids and Electrolytes. 5th edition. pp.157-163. • Robertson, J. & Shilfoski, N. (2005). Fluids and Electrolytes. The Harriet Lane Handbook. (pp. 287-300). • Sykes, R. (2007). Pediatric Fluids and Electrolytes. [PowerPoint slides].

More Related