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FLUID AND ELECTROLYTE MANAGEMENT. Houssam Fayad , MD. COMPOSITION OF BODY FLUIDS. Water is the most plentiful component of human body Total body water (TBW): constitutes 50-75% of total body mass, depending on age, sex and fat content. TBW.
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FLUID AND ELECTROLYTE MANAGEMENT Houssam Fayad , MD
COMPOSITION OF BODY FLUIDS • Water is the most plentiful component of human body • Total body water (TBW): • constitutes 50-75% of total body mass, depending on age, sex and fat content.
TBW -Fetus has a very high water content -TBW decreases to 75% in a full term neonate -During 1 year of life TBW content decreases to 60% and remains same until puberty.
FLUID COMPARTMENTS ICF 40% In newborn ECF>ICF By 1 year of age ratio of ICF to ECF approaches the adult level. INTERSTITIAL 15% ECF 20% PLASMA 5%
ELECTROLYTE COMPOSITION ECF ICF Na + K + Phos - CI - HCO3 - Prot - K + Prot - Na + Ca + HCO3 - Other Mg + Mg + Phos - CI -
OSMOLALITY • ICF and ECF are in osmotic equilibrium • Change in osmolality in one of the compartments leads to water shift through the cell membranes to normalize equilibrium • Plasma osmolality: • 285-295 mosm/kg • Calculated based on formula: • 2xNa+glucose/18+BUN/2.8
MAINTENANCE AND REPLACEMENT THERAPY • Therapy of fluid and electrolyte disorders directed toward: • Providing maintenance fluids and electrolyte requirements • Replenishing prior losses • Replace persistent abnormal losses
MAINTENANCE AND REPLACEMENT THERAPY • Maintenance fluid requirement take into account: • Normal insensible water losses • skin and lungs: • 35% • Urine: • 60% • Stool • 5% • Assuming that patient is afebrile and relatively inactive
MAINTENANCE AND REPLACEMENT THERAPY • Maintenance fluids are used when a child cannot be fed orally. • Replacement therapy needed when patient has excessive ongoing losses from NG tube, ongoing diarrhea or vomiting or high urine output due to nephrogenic diabetes insipidus. • Deficit therapy corrects dehydration or prior losses
COMPOSITION OF MAINTENANCE FLUIDS • Water • Glucose • Sodium • Potassium
GOALS OF MAINTENANCE FLUIDS • Prevent dehydration • Prevent electrolyte disorders • Prevent starvation ketoacidosis • Prevent protein degradation
MAINTENANCE WATER • 1 ml of water needed for each calorie expended
GLUCOSE IN MAINENANCE FLUIDS • How much glucose is required in maintenance fluids? • Why? • What % glucose solution will cover this requirement?
GLUCOSE IN MAINENANCE FLUIDS • 20% of patient’s true caloric requirements needed to prevent starvation ketosis and limit protein catabolism. • Example: 10 kg baby will need 1000 kcal/day 20% ----200 kcal/day from glucose 1 g glucose provides 4 kcal X g glucose provides 200 kcal X =50 g 50 g glucose in 1000 ml=> 5% glucose
MAINTENANCE ELECTROLYTES • SODIUM: • 2-3 mEq/kg/24 hr or 3 meq/100cc • POTASSIUM: • 1-2 mEq/kg/24 hr or 2 meq/100cc
SELECTION OF SODIUM CONCENTRATION IN IV MAINTENANCE FLUIDS • Based on Na requirement/kg/day • 10 kg baby needs 1000 cc of fluids and 30 meq/L Na=> ¼ NS • 20 kg baby needs 1500 cc of fluids Na requirements=3meq x 20 kg=60 meq 60 meq to be given in 1500 cc X meq to be given in 1000 cc=> and 40 meq/L Na=> ¼NS-1/3 NS • 30 kg baby needs 1700 cc of fluids and 90 meq of Na to be given in this volume of fluids=> 53 meq/L=>1/3 NS-1/2 NS
CALCULATION OF KCL REQUIREMENTS IN IV FLUIDS • Calculate maintenance water requirements • Calculate KCL requirement/kg/day • Adjust KCL per liter of fluids • EXAMPLE: • 25 kg child needs 1600 cc of maintenance water • 25kgx1-2mEq/kg/24 hr=25-50 mEq/24hr of KCL • 1600 cc of water contains 25-50 mEq of KCL 1000 cc of water contains X mEq of KCL X=15.63- 31.25 mEq=> 20 mEq
REMEMBER! • Maintenance fluids do not provide adequate calories. • Patient will lose 0.5-1% of weight each day. • TPN should be started for children who can not be fed enterally for more than a few days • Certain conditions increase or decrease maintenance requirements. Examples? • For each 1 degree increase in temperature above 38-maintenance requirements are increased by 10%
REPLACEMENT FLUIDS • Diarrhea is often associated with loss of potassium and bicarbonate leading to metabolic acidosis and hypokalemia. • Concurrently, volume depletion leads to hypoperfusion and lactic acidosis.
ADJUSTING FLUID THERAPY IN DIARRHEA • Average composition of diarrhea: Sodium: 55 meq/L Potassium: 25 meq/L Bicarbonate: 15 meq/L
APPROACH TO REPLACEMENT THERAPY • GI losses can be measured • Replace losses as they occur every 2-6 hours depending on the rate cc by cc • Use appropriate solution close in composition to electrolytes being lost • Child should receive appropriate maintenance therapy in addition to replacement therapy • Daily BMP
LOSS OF GASTRIC FLUID • Can occur via emesis or NG suction • What electrolytes are lost with gastric fluids? • Sodium 60 meq/L • Chloride 90 meq/L • Potassium 10 meq/L • What metabolic disturbances it can cause? • hypokalemia and metabolic alkalosis
THIRD SPACE LOSSES • Occur after abdominal surgery • Results in shift of fluid from intravascular space into interstitial space • Isotonic loss- best replaced by NS or RL • Cannot be quantitated • Replacement is based on continuing assessment of intravascular volume status
DEHYDRATION-the most frequent reason for hospitalization INCREASE LOSSES DECREASED INTAKE • Vomiting: • AGE • Pyloric stenosis • Pyelonephritis • Increased ICP • Abdominal obstruction • Appendicitis • Pancreatitis, etc • Diarrhea: • AGE • Malabsorption • milk-protein allergy, • IBD • DKA, DI, burns • Gingivostomatitis • Pharyngitis • Fever • Altered mental status • Physical restriction • Dependence on caregiver
DEHYDRATION SCORING SYSTEM • Decreased skin elasticity • Capillary refill>2 sec • Ill appeared(tired, somnolent, “washed out”) • Absent tears • Abnormal respirations • Dry mucous membranes • Sunken eyes • Abnormal radial pulse • Tachycardia • Decreased urine output (parental report)
DEHYDRATION SCORING SYSTEM • Score 0- no dehydration • Score 1-2- mild • Score 3-6-moderate • Score 7-10- severe
LABORATORY FINDING IN DEHYDRATION-BMP • Disproportionate increase of BUN with little or no change of Creatinine • due to increase passive reabsorption of urea in proximal tubule due to appropriate conservation of Na and water
LABORATORY FINDINGS IN DEHYDRATION • What changes in urinalysis may be present in dehydration? • Elevation of spesific gravity • Proteinuria 30-100 mg/dL • Few WBC and RBC • Hyaline and granular casts
APPROACH TO DEHYDRATION • Acute intervention to restore intravascular volume and improve perfusion • NS bolus 20 cc/hr over 20 min • Deficit correction : • Total amount of fluids includes maintenance and deficit fluid • Bolus is subtracted from the total volume • Half of total fluids given over the first 8 hr, reminder half-over the last 16 hr
ORAL DEHYDRATION THERAPY • Best used in the absence of shock • When poor perfusion is present • isotonic fluid bolus can restore perfusion, then oral rehydration can proceed. • Glucose is actively absorbed and Na is co-transported across gut mucosa • optimal glucose transport at concentrations: • glucose 2-2.5gm/L Na 45-90 mEq/L • higher glucose concentration will exacerbate diarrhea and Na loss
ORAL REHYDRATION THERAPY • Aim is to replace fluid deficit over 4-6 hours • Calculate total volume to be given over 4 hours: • MILD=50 cc/kg • MODERATE=100 cc/kg • Calculate 5 min. aliquot volume: • Administer aliquot over 5 min period • Increase volume as tolerated • Maintenance: 100 mL of ORS/kg/24
EXAMPLE • 7 y.o. boy is admitted with 2-day hx of vomiting and diarrhea. He is estimated to be 7% dehydrated and vomited all attempts at oral dehydration in ER. He was given 20 cc/kg of NS bolus prior to transfer to the floor. His weight is 23 kg
EXAMPLE • Maintenance water: 1560 cc=>65 cc/hr • Maintenance Na= 2-3 meq x 23 kg=46-69meq • Maintenance K=1-2 meq x 23=23-46 meq • Total fluid deficit=23kg x 0.07 x 1000cc/kg=1610 cc • Previous replacement=23 kg x 20cc/kg=460cc • Balance fluid deficit= 1610-460=1150cc=>1/2 is given over the first 8 hr=72 cc/hr; another ½ over the last 16 hr=36 cc/hr
QUESTIONS • You are called to the ER to see a 4 month old baby boy for admission as he has been having nasal congestion and cough with decreases oral intake of one day duration. Wet diapers decreased in the past 24 hours. Vital signs as follow: HR of 160, RR of 50, O2 sat =95%, temp = 100.7, weight = 17 Ibs. Normal physical examination. • What percentage of dehydration is he? • How do you manage his fluids • Bolus • Maintenance fluids
QUESTIONS • You are the resident in the pediatric floor and your fellow resident left you with an admission. The patient is a 5 year old male with sickle cell whom is being admitted as he has fever (Tmax 103F) x 2 days, vomiting x 2 days (1 to 2 episoded per day), pain all over and decreased po. • Vital signs: pulse = 180, RR= 60, stable BP, O2 sat = • 88% and. Weight = 44 Ibs. • Physical examination shows crackles, dry mucous membranes, cap refill 3 sec and he is in obvious distress as he is crying in pain • Percentage of dehydration • Fluid management and type of fluid
QUESTIONS • You are assessing a 4 year old female for diarrhea x 7 days, fever x 4 days with Tmax of 101F, decreased po intake and sleeping more than usual. • Vital signs: T=102F, Pulse = 130, RR= 20, O2 sat =100%and BP = 60/50. Weight =35 Ib • Physical examination pertinent for a girl that is lethargic but arousable to speech and touch, cap refil is 4 sec • 1) What is the percentage of dehydration ? • 2) What type of fluid are you going to use • 3) What is your management for her fluids
QUESTIONS • A one week old infant present to the ER with vomiting x 3 days, diarrhea x 3 days, not feeding well, decreased wet diapers x 2 days with no urine x 24 hours. • Vital signs: Pulse = 180, RR= 80, Bp= 40/30, sat = 78% • Weight = 7 Ibs • Physical examination: lethargic, depressed anterior fontanelle, doghey skin, dry mucous memebranes and cap refil is 4 sec. • What is the percentage of dehydration • What type of fluid would you use for a bolus • What is her fluid management?
QUESTIONS • This is a one year old female presenting to the ER s/p tonsillectomy 3 days ago as she is in pain, not eating or drinking well and with a fever. Decrease wet diapers x 1 day. • Vital signs P=100, RR=22, BP= xx, sat =100% • Weight =24 Ibs • Physical examination: she is irritable with examination but consolable, cries with tears, cap refill 2 sec, tonsillar bed with whitish tissue, rest of exam normal • 1) Percent of dehydration • 2) What type of fluids are you going to use • 3) Would you give her a bolus? What about maintenace fluids.
QUESTIONS • This is a 6 year old male with hx of asthma whom is presenting to the ER with c/o breathing fast, SOB, and wheezing x 1 day. Mother ran out of his medaications. • Vital signs: P= 140, RR= 55, BP = xx, O2 sat = 85% • Weight = 55 Ibs • Physical examination pertinent for subcostal and intercostal retractions, expiratory wheezing and decrease air entry. • Would you bolus him? If so with what? • Type of fluids? Fluid management?