Basic Fluid Management …with references to the Harriet Lane (because you have it with you) Julie Story Byerley, MD, MPH.

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  • Slide 1
  • Basic Fluid Management with references to the Harriet Lane (because you have it with you) Julie Story Byerley, MD, MPH
  • Slide 2
  • Why does fluid management matter? Its basic pediatrics. Its basic pediatrics. Pediatricians are supposed to be the experts of fluid management. Pediatricians are supposed to be the experts of fluid management. It matters to just about every inpatient. It matters to just about every inpatient. Fluid is often extremely effective therapy. Fluid is often extremely effective therapy. Incorrect fluid management can seriously hurt patients. Incorrect fluid management can seriously hurt patients. Its not always as simple as you might think but you can make it simple. Its not always as simple as you might think but you can make it simple.
  • Slide 3
  • Outline Maintenance requirements Maintenance requirements Management of dehydration Management of dehydration Normonatremic Normonatremic Hyponatremic Hyponatremic Hypernatremic Hypernatremic A few little pearls A few little pearls
  • Slide 4
  • Maintenance requirements Chapter 10, Harriet Lane, p. 233 The two functions of maintenance fluids include The two functions of maintenance fluids include Solute excretion in urine Solute excretion in urine Heat dissipation through insensible losses of water Heat dissipation through insensible losses of water Insensible losses are about 2/3 skin and 1/3 lungs Insensible losses are about 2/3 skin and 1/3 lungs Each can be considered as about 50% when maintenance needs are exactly met and urine concentration is 1.010 Each can be considered as about 50% when maintenance needs are exactly met and urine concentration is 1.010 The kidneys are usually smart insensible losses come first (less adjustable) and the kidneys can then adjust how much water is in the urine The kidneys are usually smart insensible losses come first (less adjustable) and the kidneys can then adjust how much water is in the urine
  • Slide 5
  • Maintenance Requirements Caloric Expenditure Method Caloric Expenditure Method Holliday-Segar Method Holliday-Segar Method Body Surface Area Method Body Surface Area Method Remember that maintenance requirements are over about 24 hours, and dont have to be given evenly divided over each hour Remember that maintenance requirements are over about 24 hours, and dont have to be given evenly divided over each hour
  • Slide 6
  • Caloric Expenditure Method Water and electrolyte needs parallel caloric needs Water and electrolyte needs parallel caloric needs Caloric needs depend on activity Caloric needs depend on activity For each 100 kcals, For each 100 kcals, 100-120 cc water, 100-120 cc water, 2-4 MEq Na, and 2-4 MEq Na, and 2-3 MEq K are needed 2-3 MEq K are needed
  • Slide 7
  • Average Caloric Needs See page 436 in Harriet Lane (table 20-1) At normal activity At normal activity Infants approx. 100 kcal/kg/d Infants approx. 100 kcal/kg/d 4-6yo approx. 90 kcal/kg/d 4-6yo approx. 90 kcal/kg/d 7-10yo approx. 70 kcal/kg/d 7-10yo approx. 70 kcal/kg/d Teens approx. 50 kcal/kg/d Teens approx. 50 kcal/kg/d Caloric needs are based on resting energy expenditure and activity Caloric needs are based on resting energy expenditure and activity Resting energy expenditure (REE) is based on size Resting energy expenditure (REE) is based on size Energy needs increase with injury, fever, growth, etc. Energy needs increase with injury, fever, growth, etc. See p. 435 in Harriet Lane See p. 435 in Harriet Lane REE (Resting Energy Expenditure) REE (Resting Energy Expenditure) + REE X (Mtn + Injury + Activity + Growth) Dont memorize it, just get the concept Dont memorize it, just get the concept
  • Slide 8
  • Example, Caloric Expenditure Method 10 yo boy with injuries and fever, 30kg 10 yo boy with injuries and fever, 30kg = REE + REE x (Mtn + Activ + Fever + Inj + Growth) = REE + REE x (Mtn + Activ + Fever + Inj + Growth) = 40 + 40 x(0.2 + 0.1 + 0.13 + 0.4 + 0.5) = 40 + 40 x(0.2 + 0.1 + 0.13 + 0.4 + 0.5) = 40 + 40 x(1.33) = 40 + 40 x(1.33) = 93 kcal/kg/d = 2790 kcal/d = 93 kcal/kg/d = 2790 kcal/d Therefore, he needs 2790 cc water per day Therefore, he needs 2790 cc water per day water needs parallel caloric needs water needs parallel caloric needs 3 MEq Na/(100 kcals) = 84 MEq Na total per day 3 MEq Na/(100 kcals) = 84 MEq Na total per day 2 MEq K/(100 kcals) = 56 MEq K total per day 2 MEq K/(100 kcals) = 56 MEq K total per day
  • Slide 9
  • The Math what fluid? D5 is standard D5 is standard 2790 cc of D5 has only 474 kcals 2790 cc of D5 has only 474 kcals only 16 kcal/kg/d only 16 kcal/kg/d people are malnourished when they only receive IVF! people are malnourished when they only receive IVF! 84 MEq Na/ 2790 cc = X / 1000; X = 30 84 MEq Na/ 2790 cc = X / 1000; X = 30 Quarter NS = 38.5 MEq Na/L Quarter NS = 38.5 MEq Na/L 56 MEq K/ 2790 cc = Y / 1000; Y = 20 56 MEq K/ 2790 cc = Y / 1000; Y = 20 Try D5 quarter NS with 20 KCl at 116 cc/hour Try D5 quarter NS with 20 KCl at 116 cc/hour More fluid than using the 4:2:1 rule (70cc/h); necessary because of injuries and fever More fluid than using the 4:2:1 rule (70cc/h); necessary because of injuries and fever
  • Slide 10
  • Holliday-Segar Method Estimates caloric and fluid needs from weight alone Estimates caloric and fluid needs from weight alone Can over-estimate fluid needs for infants and under-estimate fluid needs in fever and injury Can over-estimate fluid needs for infants and under-estimate fluid needs in fever and injury Method we tend to use most commonly Method we tend to use most commonly 4,2,1 rule 4,2,1 rule
  • Slide 11
  • Holliday-Segar Method Weightcc/kg/dcc/kg/h First 10 kg 1004 Second 10 kg 502 Each additional kg 201 Ex: 25 kg 1600 cc/d (1000+500+100) 65 cc/h
  • Slide 12
  • Holliday-Segar Method Electrolyte Requirements Electrolyte Requirements Na 3 MEq per 100 cc water Na 3 MEq per 100 cc water K - 2 MEq per 100 cc water K - 2 MEq per 100 cc water Example, 25 kg kid, 1600 cc/d Example, 25 kg kid, 1600 cc/d 48 Meq Na, 32 Meq K 48 Meq Na, 32 Meq K 48/1600 = X/1000; X = 30 48/1600 = X/1000; X = 30 (Remember that quarter NS has 38.5 MEq/L Na) (Remember that quarter NS has 38.5 MEq/L Na) 32/1600 = Y/ 1000; Y= 20 32/1600 = Y/ 1000; Y= 20 D5 quarter NS with 20 MEq/L KCl (as Cl is your anion to fill with) D5 quarter NS with 20 MEq/L KCl (as Cl is your anion to fill with)
  • Slide 13
  • Sodium Since the ratio of electrolytes needed to amount of water does not change, the Na concentration in MIVF does not need to change based on weight Since the ratio of electrolytes needed to amount of water does not change, the Na concentration in MIVF does not need to change based on weight Often people use D5 NS for small babies and D5 1 / 2 NS for bigger kids and adults Often people use D5 NS for small babies and D5 1 / 2 NS for bigger kids and adults This can give adults more sodium than needed This can give adults more sodium than needed This error is based on the fact that fluid needs decrease as size increases This error is based on the fact that fluid needs decrease as size increases Na should be calculated based on kcals, (therefore ccs not kg) Na should be calculated based on kcals, (therefore ccs not kg) We decrease water needs as weight increases (the 4,2,1 rule), but we tend to calculate Na needs as 3 MEq per kg per day. Na needs are not linear. They should decrease like water needs do. We decrease water needs as weight increases (the 4,2,1 rule), but we tend to calculate Na needs as 3 MEq per kg per day. Na needs are not linear. They should decrease like water needs do. Many argue that D5 NS with 20 K is an appropriate maintenance fluid for all people. Many argue that D5 NS with 20 K is an appropriate maintenance fluid for all people.
  • Slide 14
  • Body Surface Area Method Method not used as frequently, but often taught in nephrology Method not used as frequently, but often taught in nephrology More difficult to use with small children More difficult to use with small children To calculate the BSA you need to know height To calculate the BSA you need to know height Maintenance requirements are about 1500 ml/m2/day Maintenance requirements are about 1500 ml/m2/day
  • Slide 15
  • Dehydration
  • Slide 16
  • Background Dehydration complicates many acute illnesses Accurate assessment is important Consequences of under- estimation Consequences of under- estimation Consequences of over-estimation Consequences of over-estimation Practice guidelines for evaluation and management Practice guidelines for evaluation and management
  • Slide 17
  • Dehydration Initial resuscitation Initial resuscitation Determining deficit Determining deficit Adding in maintenance Adding in maintenance Ongoing losses (dont forget!) Ongoing losses (dont forget!)
  • Slide 18
  • Estimating degree of dehydrationtraditional teaching Recent weight changes Recent weight changes Physical exam findings Physical exam findings
  • Slide 19
  • Caveatstraditional teaching The previous chart applies to babies. For adults it should be scaled back to 3%, 6%, and 9%. The previous chart applies to babies. For adults it should be scaled back to 3%, 6%, and 9%. Older kids show symptoms at a lower % dehydration Older kids show symptoms at a lower % dehydration Hyponatremic dehydration looks worse clinically exaggerated hemodynamic instability Hyponatremic dehydration looks worse clinically exaggerated hemodynamic instability Hypernatremic dehydration looks better clinically circulation maintained at the expense of intracellular volume Hypernatremic dehydration looks better clinically circulation maintained at the expense of intracellular volume
  • Slide 20
  • Systematic Review of the Published Data on History, PE, and Labs in Dehydration Mike Steiner, Darren DeWalt, Julie Byerley, 2002-3
  • Slide 21
  • Historical Factors Previous visit to PCP, or previous trial of clears provided minimal but some increase in the likelihood of dehydration Previous visit to PCP, or previous trial of clears provided minimal but some increase in the likelihood of dehydration Physical exam signs less helpful than previously taught Physical exam signs less helpful than previously taught
  • Slide 22
  • Delayed Capillary Refill Limitations: Inter-rater agreement only slight to fair Inter-rater agreement only slight to fair Kappa 0.01-0.35 Kappa 0.01-0.35 Site of application, lighting and ambient temperature Site of application, lighting and ambient temperature SensitivitySpecificityLR PositiveLR Negative 0.60 (0.30- 0.91) 0.85 (0.72-0.98) 4.1 (1.7-9.8) 0.6 (0.4-0.8)
  • Slide 23
  • Abnormal Skin Turgor Limitations: Inter-rater agreement fair to moderate Inter-rater agreement fair to moderate Kappa 0.36-0.55 Kappa 0.36-0.55 Hypernatremia increases false negatives Hypernatremia increases false negatives SensitivitySpecificityLR PositiveLR Negative 0.58 (0.40-0.75) 0.76 (0.59-0.93) 2.5 (1.5-4.2) 0.7 (0.6-0.8)
  • Slide 24
  • Abnormal Respirations Limitations: Inter-rater agreement of only chance to fair Inter-rater agreement of only chance to fair Kappa 0.04 to 0.40 Kappa 0.04 to 0.40 Varying measurements and definitions Varying measurements and definitions SensitivitySpecificityLR PositiveLR Negative 0.43 (0.3-0.6) 0.79 (0.7-0.9) 2.0 (1.5-2.7) 0.7 (0.6-0.9)
  • Slide 25
  • Less Useful Signs SignComment Sunken Eyes Pooled LR of 1.7 Dry MM Pooled LR of 1.7 Weak PulseLR ranged from not significant to 3.1 sensitivity low (0.04-0.25), specificity high (0.89 to 1) Cool ExtremityLR ranged from not significant to 18.8 Absent tearsPooled LR CI crosses 1.0 Abnormal overall appearance Pooled LR CI crosses 1.0 TachycardiaPooled LR CI crosses 1.0 Weak CryCI for LR crosses 1.0. Sunken fontanelleLR actually below one, CI crosses 1.0
  • Slide 26
  • Combinations of Signs Vega evaluated the standard dehydration table Severe classification Severe classification LR 3.4 for 5% dehydration LR 3.4 for 5% dehydration Mild or Moderate classification Mild or Moderate classification No increase in likelihood of dehydration No increase in likelihood of dehydration Gorelick found an LR of 4.9 when 3/10 signs of dehydration present
  • Slide 27
  • Results: Laboratory Tests BUN Study of hospitalized patients with gastroenteritis Study of hospitalized patients with gastroenteritis BUN >45, specificity: 1.00, LR positive of 46.1 BUN >45, specificity: 1.00, LR positive of 46.1 BUN cutoffs of 8, 18, and 27 yielded mixed results in four other studies BUN cutoffs of 8, 18, and 27 yielded mixed results in four other studies Acidosis One study found no statistical increase in likelihood One study found no statistical increase in likelihood Four studies found significant positive LRs between 1.5 and 3.5 Four studies found significant positive LRs between 1.5 and 3.5
  • Slide 28
  • Discussion Poor to moderate inter-observer agreement History and parental report have limited value Best individual tests Prolonged capillary refill Prolonged capillary refill Abnormal skin turgor Abnormal skin turgor Abnormal respirations Abnormal respirations Groups of positive signs are helpful Extremely abnormal lab tests are helpful
  • Slide 29
  • Implications Focus on symptoms and signs with proven utility Ability to estimate exact degree of dehydration is limited Support change to none, some, or severe classification scheme
  • Slide 30
  • Oral Rehydration Recommended by the AAP, WHO, and CDC Recommended by the AAP, WHO, and CDC Appropriate for mild-moderate (some) dehydration Appropriate for mild-moderate (some) dehydration Goal is 50-100 cc/kg over 4 hours for mild-moderate dehydration Goal is 50-100 cc/kg over 4 hours for mild-moderate dehydration 5 cc every 1-2 minutes 5 cc every 1-2 minutes Solution containing 40-60 MEq/L Na Solution containing 40-60 MEq/L Na
  • Slide 31
  • The Fluid Used Matters
  • Slide 32
  • Fluid Management in Shock Initial boluses of 20 cc/kg over 30 min Initial boluses of 20 cc/kg over 30 min 20 cc/kg is 2% of body weight therefore it should take a 10% dehydrated baby to only 8% dry 20 cc/kg is 2% of body weight therefore it should take a 10% dehydrated baby to only 8% dry One bolus is not enough when someone is 15% dry One bolus is not enough when someone is 15% dry Use isotonic solutions (NS, LR) Use isotonic solutions (NS, LR) Consider blood, other fluids and/or pressors in special circumstances Consider blood, other fluids and/or pressors in special circumstances Trauma or blood loss Trauma or blood loss Nephrotic syndrome Nephrotic syndrome Septic and cardiogenic s...

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