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- 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 shock Septic and cardiogenic shock Slide 33 Fluid Composition Fluid CHO g/100cc Cal/LNaKClCO3Ca D5W5170 NS (0.9% NaCl) 154154 LR0-100-3401304109283 Slide 34 Rehydration First resuscitate out of shock restore perfusion First resuscitate out of shock restore perfusion Calculate maintenance, including ongoing losses, and deficit Calculate maintenance, including ongoing losses, and deficit Run maintenance as usual Run maintenance as usual Replace ongoing losses Replace ongoing losses Typical is to replace deficit over 24 hours Typical is to replace deficit over 24 hours Half in first 8 hours Half in first 8 hours Other half over 16 hours Other half over 16 hours Slide 35 Where the dehydration comes fromtraditional teaching In a brief duration of illness ( Example Calculations, normal Na (See table 10-7 in Harriet Lane on page 237.) 7 kg infant with 10% dehydration that accumulated over >3d. 24 Hours H2ONaK Maintenance (Hol.-Seg.) 7002114 Deficit (10% of 7 kg) 700 ECF (60%) 42061 (145MEq/L x 0.42L) ICF (40%) 28042 (150MEq/L x 0.28L) Total1400cc82MEq56MEq Slide 37 First 8 hours MIVF for 8 hours plus 50% of the deficit MIVF for 8 hours plus 50% of the deficit 583/8=73 cc/h; 38/0.583=65MEqNa/L = 0.42NS (65/154); 26/0.583=45MEqK/L 583/8=73 cc/h; 38/0.583=65MEqNa/L = 0.42NS (65/154); 26/0.583=45MEqK/L Roughly D5halfNS plus 40 KCl at 75 cc/h Roughly D5halfNS plus 40 KCl at 75 cc/h H2ONaK 1 / 3 Maint 23375 Deficit 3503121 Total5833826 Slide 38 Next 16 hours MIVF for 16 hours plus other 50% of the deficit MIVF for 16 hours plus other 50% of the deficit 817/16=51 cc/h; 44/0.817=54MEqNa/L = 0.35NS (54/154); 30/0.817=37MEqK/L 817/16=51 cc/h; 44/0.817=54MEqNa/L = 0.35NS (54/154); 30/0.817=37MEqK/L Roughly D5halfNS plus 40 KCl at 50 cc/h Roughly D5halfNS plus 40 KCl at 50 cc/h H2ONaK 2 / 3 Maint 467149 Deficit 3503021 Total8174430 Slide 39 Simplified what fluid, normal Na (Roberts method) Usually after boluses with NS or LR, D5halfNS is an appropriate rehydration fluid Usually after boluses with NS or LR, D5halfNS is an appropriate rehydration fluid After urine output is assured, give K as 20 MEq/L After urine output is assured, give K as 20 MEq/L That is usually safe That is usually safe Often you dont need to fully replete K losses acutely Often you dont need to fully replete K losses acutely Watch the rate of fluids regarding K and dont give more than 1 MEq/kg/h Watch the rate of fluids regarding K and dont give more than 1 MEq/kg/h Slide 40 Simplified what rate (Roberts method) If a child is 10% dehydrated - If a child is 10% dehydrated - Give a 20 cc/kg bolus of NS Give a 20 cc/kg bolus of NS Restores hydration 2% Restores hydration 2% Next give 10 cc/kg/h of D5halfNS with 20 KCl for 8 hours Next give 10 cc/kg/h of D5halfNS with 20 KCl for 8 hours Restores hydration 8% Restores hydration 8% Next give 1.5 times MIVF using D5quarterNS with 20KCL for 16 hours Next give 1.5 times MIVF using D5quarterNS with 20KCL for 16 hours That days maintenance That days maintenance Slide 41 Example, the Roberts method 7kg child with 10% dehydration 7kg child with 10% dehydration Bolus of 140 cc NS Bolus of 140 cc NS 70 cc/h of D5halfNS with 20 KCL for 8 hours, then 70 cc/h of D5halfNS with 20 KCL for 8 hours, then 40 cc/h of D5quarterNS with 20 KCL for 16 hours 40 cc/h of D5quarterNS with 20 KCL for 16 hours Slide 42 Hyponatremia Always measure the sodium. Hyponatremic patients look more dehydrated than they probably are. Slide 43 Example calculation, hyponatremia (7kg with 10% dehydration, Na 115, >3 d duration) Table 10-8 on p. 238 Fluid deficit same as before Fluid deficit same as before 10% of 7 kg=700 ml total fluid deficit 10% of 7 kg=700 ml total fluid deficit 60% from ECF, 40% from ICF 60% from ECF, 40% from ICF Na deficit (from dehydration) same as before Na deficit (from dehydration) same as before ECF Na x 60% of total fluid deficit ECF Na x 60% of total fluid deficit 145 mEq/L x.6 x.7L = 61mE 145 mEq/L x.6 x.7L = 61mE Excess Na deficit (because hyponatremic) Excess Na deficit (because hyponatremic) (Desired Na Actual Na) x distribution factor x wt (Desired Na Actual Na) x distribution factor x wt (CD-CA) x fD x weight (CD-CA) x fD x weight (135-115)MEq/L x 0.6L/kg x 7kg = 84 mEq Na (135-115)MEq/L x 0.6L/kg x 7kg = 84 mEq Na Replace excess Na deficit over 24 hours Replace excess Na deficit over 24 hours Replace Na faster if symptomatic Replace Na faster if symptomatic Slide 44 K deficit (same as before) K deficit (same as before) ICF K x 40% of total fluid deficit ICF K x 40% of total fluid deficit 150mEq/L x 0.4 x 0.7L=42 mEq 150mEq/L x 0.4 x 0.7L=42 mEq Make a table! Make a table! Slide 45 First 8 hours, hyponatremia MIVF for 8 hours plus 50% of the deficit MIVF for 8 hours plus 50% of the deficit 583/8=73 cc/h; 80/0.583=137MEqNa/L = 0.89NS (137/154); 26/0.583=45MEqK/L 583/8=73 cc/h; 80/0.583=137MEqNa/L = 0.89NS (137/154); 26/0.583=45MEqK/L Roughly D5halfNS plus 40 KCl at 75 cc/h Roughly D5halfNS plus 40 KCl at 75 cc/h H2ONaK 1 / 3 Maint 23375 Deficit 3507221 Total5838026 Slide 46 Next 16 hours, hyponatremia MIVF for 16 hours plus other 50% of the deficit MIVF for 16 hours plus other 50% of the deficit 817/16=51 cc/h; 86/0.817=105MEqNa/L = 0.68NS (105/154); 30/0.817=37MEqK/L 817/16=51 cc/h; 86/0.817=105MEqNa/L = 0.68NS (105/154); 30/0.817=37MEqK/L Roughly D5halfNS plus 40 KCl at 50 cc/h Roughly D5halfNS plus 40 KCl at 50 cc/h H2ONaK 2 / 3 Maint 467149 Deficit 3507221 Total8178630 Slide 47 Practical Interpretation, Hyponatremia In adults, rapid correction of hyponatremia may be associated with central pontine myelinoysis. In adults, rapid correction of hyponatremia may be associated with central pontine myelinoysis. Correct the Na fast only if the patient is symptomatic (seizing or particularly irritable) Correct the Na fast only if the patient is symptomatic (seizing or particularly irritable) For asymptomatic patients, the goal should be to increase the Na no faster than 1 MEq/L per hour For asymptomatic patients, the goal should be to increase the Na no faster than 1 MEq/L per hour Start with NS boluses and then D5NS or D5halfNS Start with NS boluses and then D5NS or D5halfNS Follow Na carefully Follow Na carefully Slide 48 Hypernatremia Always measure the sodium Slide 49 Hypernatremia In hypernatremia, rehydrate more slowly to avoid fluid shifts that could cause cerebral edema or intracranial bleeding In hypernatremia, rehydrate more slowly to avoid fluid shifts that could cause cerebral edema or intracranial bleeding Remember that the hypernatremic patient doesnt always look as dry as they are because the intravascular volume is protected Remember that the hypernatremic patient doesnt always look as dry as they are because the intravascular volume is protected The hypernatremic dehydrated patient is still sodium depleted, but in addition has lost free water The hypernatremic dehydrated patient is still sodium depleted, but in addition has lost free water Free water losses must be calculated and subtracted from total deficit to calculate the solute deficit Free water losses must be calculated and subtracted from total deficit to calculate the solute deficit Slide 50 Example calculation, hypernatremia (7kg with 10% dehydration, Na 155, >3 d duration) Table 10-9 on p. 239 Same fluid deficit, maintenance fluid and electrolytes as before, in isotonic dehydration example Same fluid deficit, maintenance fluid and electrolytes as before, in isotonic dehydration example FW deficit FW deficit =(measured Na ideal Na)x 4cc/kg x wt FW def = (155-145) x 4 x 7 = 280 cc FW def = (155-145) x 4 x 7 = 280 cc Replace free water deficit evenly over 48 h Replace free water deficit evenly over 48 h Give only half of FW deficit in first day Give only half of FW deficit in first day Drop Na less than 15 MEq/L/day Drop Na less than 15 MEq/L/day Follow lytes closely every 4 hours at first Follow lytes closely every 4 hours at first Subtract the free water deficit from the total deficit to determine Na deficit Subtract the free water deficit from the total deficit to determine Na deficit Slide 51 Chart for Hypernatremia, first 24 h H2ONaK MIVF7002114 Free water deficit = 280cc/2 days 140 Def remaining (solute) =420cc (700-280=420) ECF (60%) ECF (60%) ICF (40%) ICF (40%)2521683725 Total, 24 hr 12605839 Slide 52 Fluid choice, Hypernatremia Need in 24 hours, Need in 24 hours, 1260 cc water 1260 cc water 58 Meq Na 58 Meq Na 39 MEq K 39 MEq K 1260/24 = 52.5 cc/h 1260/24 = 52.5 cc/h 58/1.260 = 46 MEqNa/L = 0.3 NS (46/154) 58/1.260 = 46 MEqNa/L = 0.3 NS (46/154) 39/1.260 = 31MEqK/L 39/1.260 = 31MEqK/L Roughly D5halfNS with 30KCl at 50 cc/h could also use D5quarterNS half is more conservative Roughly D5halfNS with 30KCl at 50 cc/h could also use D5quarterNS half is more conservative Slide 53 Practical Interpretation, Hypernatremia Still bolus the hypernatremic patient with NS if needed Still bolus the hypernatremic patient with NS if needed You want to lower the Na slowly so you can start with D5halfNS and remeasure You want to lower the Na slowly so you can start with D5halfNS and remeasure The calculations almost always come out to something near quarter NS, and you should not give more dilute fluid than that, so that is also a reasonable starting point The calculations almost always come out to something near quarter NS, and you should not give more dilute fluid than that, so that is also a reasonable starting point The important thing is to follow the sodium carefully and adjust as necessary The important thing is to follow the sodium carefully and adjust as necessary Slide 54 Practical Approach, Replacing the Deficit Isotonic dehydration 1/2 NS Hyponatremic dehydration 3/4 or NS Hypernatrmic dehydration 1/4 NS Follow I/Os, weights, lytes carefully q 4 hours, you can follow on VBGs Slide 55 Even EasierRun Maintenance and Deficit Separately Maintenance (calculate using Holliday-Segar) Y in Deficit Ongoing losses (calculate by shift or anticipate) Use the same calculations as above to calculate the deficit, but hang different fluids Generally easier to manage than having unusual fluids mixed by pharmacy Slide 56 Ongoing losses Dont forget losses into third spaces Dont forget losses into third spaces Pay attention to In-Out sheets Pay attention to In-Out sheets Replace shift to shift if output is large Replace shift to shift if output is large Check electrolytes on output prn Check electrolytes on output prn Slide 57 Ongoing losses! Usually replace GI losses with half normal Usually replace GI losses with half normal Radiant losses are usually just water Radiant losses are usually just water See table 10-11, p.240, for other specific situations See table 10-11, p.240, for other specific situations Slide 58 Special situations Symptomatic hyponatremia (szs) Symptomatic hyponatremia (szs) 10-12mL/kg of 3% saline over 60 minutes 10-12mL/kg of 3% saline over 60 minutes Increased insensible losses Increased insensible losses When the kidneys are not smarter than you! When the kidneys are not smarter than you! Electrolyte abnormalities Electrolyte abnormalities Slide 59 THE END Slide 60 Other Equations, Anion Gap Anion gap = Na (Cl + HCO3) Anion gap = Na (Cl + HCO3) Normal gap 12 +/- 4 Normal gap 12 +/- 4 AG increased in acid production or decreased acid excretion AG increased in acid production or decreased acid excretion Ketones, lactic acidosis, inborn errors of metabolism Ketones, lactic acidosis, inborn errors of metabolism Renal failure Renal failure AG normal in hyperchloremic acidosis AG normal in hyperchloremic acidosis GI loss of bicarb GI loss of bicarb Renal loss of bicarb Renal loss of bicarb Slide 61 Other Equations, Osmolality Osmolality is number of particles per liter Osmolality is number of particles per liter Approximated by: Approximated by: 2(Na) + (glu/18) + (BUN/2.8) 2(Na) + (glu/18) + (BUN/2.8) Where glucose and BUN are in mg/dl Where glucose and BUN are in mg/dl Normal is 285-295 Normal is 285-295 Slide 62 A Pearl about Blood Transfusion See p. 319 in Harriet Lane (table 15.7) See p. 319 in Harriet Lane (table 15.7) Vol PRBC needed to transfuse = Vol PRBC needed to transfuse = EBV (cc) multiplied by (desired HCT actual HCT)/ HCT of PRBCs EBV (cc) multiplied by (desired HCT actual HCT)/ HCT of PRBCs Ex: Transfuse a 6 mo old with HCT 20% with 87.5 cc to get their HCT to 30% cc PRBC = 75cc/kg(7kg)(.10)/0.60