Pediatric Respiratory Physiology Drs. Greg and Joy Loy Gordon February 2005.
Pediatric Fluid Management and Blood Product Therapy Joy Loy, M.D. MetroHealth Medical Center April,...
-
Upload
steven-glenn -
Category
Documents
-
view
214 -
download
0
Transcript of Pediatric Fluid Management and Blood Product Therapy Joy Loy, M.D. MetroHealth Medical Center April,...
Pediatric Fluid Management
and
Blood Product Therapy
Joy Loy, M.D.MetroHealth Medical Center
April, 2004
ASA Fasting Guidelines
Clear liquids 2 hours
Breast Milk 4 hours
Infant Formula
Neonates 4 hours
Infants 6 hours
Nonhuman Milk 6 hours
Solids 8 hours
• water, juice without pulp, carbonated
beverages, clear tea, black coffee
• should not contain alcohol
• type of liquid ingested important than
volume infants < 5 mos 10 ml/kg children and adults 15 ml/kg
Clear Liquids
• is NOT a clear liquid
• does contain milk solids
Breast Milk
• cleared from the stomach more
quickly than nonhuman milk
ASA Fasting Guidelines
• pre-op fast does not guarantee an empty stomach
• timing of last fluid ingestion has little relation to
volume of gastric contents at induction
ASA Fasting Guidelines
• gastric fluid volume and pH are independent
of duration fluid fast beyond 2 hours
• main determinant: endogenous gastric
secretion
ASA Fasting Guidelines
• reduces the risk of pulmonary aspiration
• offering clear liquids up to 2 hours before
induction
> reduces hunger and irritability
> preserves hydration
> risk of hypoglycemia
BODY FLUID COMPOSITION
Total Body Water (TBW) =
Intracellular Fluid ( ICF ) +
Extracellular Fluid ( ECF )
Compartments
a) interstitial fluid ( ISF ) : no protein
b) plasma volume ( PV ) : with protein
* ISF and PV basically same electrolyte content
Body Fluid Composition
INFANT CHILD ADULT
Total Body Water 75 % 70 % 55-60 %
ECF 40 % 30 % 20 %
ICF 35 % 40 % 40 %
Fat 16 % 23 % 30 %
PHYSIOLOGIC CONSIDERATIONSDevelopmental Factors
CVS :
• incomplete myocardial development
• immature sympathetic innervation
IMPLICATION:
neonates and young infants are more
sensitive to
hypovolemia
PHYSIOLOGIC CONSIDERATIONSDevelopmental Factors
RENAL:
• immature renal function at birth
GFR
25% of adult level at term
adult level at age of 2 years
concentrating capacity of newborn kidney
term infant : max. 600-700 mOsm/kg
adult : max. 1200 mOsm/kg
PHYSIOLOGIC CONSIDERATIONSDevelopmental Factors
free H2O clearance :
excrete markedly dilute urine up to 50
mOsm / kg vs. 70-100 Osm/kg in adults
Na reabsorption
HCO3 /H exchange
urinary losses of K+ and Cl-
PHYSIOLOGIC CONSIDERATIONSDevelopmental Factors
IMPLICATION:
Newborn kidney has limited
capacity to compensate for volume
excess or volume depletion
PHYSIOLOGIC CONSIDERATIONSDevelopmental Factors
HEPATIC :
• limited hepatic glycogen stores
> risk of hypoglycemia
> provide 5%-10% dextrose in fluid
maintenance
> supplemental insulin for sustained
hyperglycemia from dextrose
PHYSIOLOGIC CONSIDERATIONSMetabolic and Fluid Requirements
metabolic rate
O2 consumption
neonates: 6-9 ml/kg/min
adults: 3 ml/kg/min
growth 120 kcal/kg/day
PHYSIOLOGIC CONSIDERATIONSMetabolic and Fluid Requirements
fluid requirement
> greater BSA to mass ratio in infants
> other factors:
radiant warmers fever
illness injury
thinner skin and lack of keratinization of
stratum corneum in premature neonates
Compensatory Mechanisms
1) Temporary mechanism
2) Definitive mechanism
Compensatory Mechanisms
Temporary Mechanism
> activated to maintain normal BP and normal
fluid volume
a) endogenous vasopressors
ADH, angiotensin II, catecholamines
b) transcapillary refill: ISF PV (skin turgor)
c) ADH : free H2O absorption
caution : hyponatremia using hypotonic
fluids
Compensatory Mechanisms
Definitive Mechanism
> through the kidneys
> activation of renin - angiotensin -
aldosterone (RAA) system
> urine output and urine specific gravity
Maintenance Fluids
replaces water and electrolytes lost under ordinary conditions
• Evaporative / insensible water loss (ISWL)
• Urinary and stool losses
• Growth
Maintenance Fluids
1) Evaporative or Insensible Water Loss (ISWL)
• solute-free H2O losses from skin and lungs
• 30-35 % of total maintenance volume
• 1/3 of total maintenance requirement
• affected by ambient humidity and temperature
• minimum replacement : 60-100 ml/kg/day
Maintenance Fluids
2) Urinary Losses
• 280-300 mOsm /kg of H2O
specific gravity 1.008-1.015
• 2/3 of total maintenance fluids
3) Growth
Maintenance FluidsHourly Maintenance Fluid Requirement
1) 4 - 2 -1 rule
WEIGHT FLUID
0 - 10 kg 4 ml/kg/hr
10 - 20 kg 2 ml/kg/hr
> 20 kg 1 ml/kg/hr
* reliable up to body weight of 80 kg
Hourly Maintenance Fluid Requirement
2) Holliday and Segar
WEIGHT FLUID/day
0 - 10 kg 100 ml / kg /day
10 - 20 kg 1000 + 50 ml/kg/day
> 20 kg 1500 + 20 ml/kg/day
* based on caloric requirement of hospitalized patients
Maintenance FluidsHourly Maintenance Fluid Requirement
3) OH Method
WEIGHT FLUID/hr
0 - 10 kg 4 ml / kg / hr
10 - 20 kg 20 + 2 ml/kg/hr
> 20 kg 40 + 1ml /kg/hr
Choice of Maintenance Fluids
• Remains controversial
• Hypotonic solution
D5 1/2 NS + 20 mEq KCl
D5 1/4 NS : may be a better choice in
neonates due to their limited ability
to handle Na + loads
• Balanced salt solution
Guide for Maintenance Fluid Therapy
Newborn Term
Day 1 50-60 ml/kg/day D10 W
Day 2 100 ml/kg/day D10 1/2 NS
>Day 7 100-150 ml/kg/day D5-D10 1/4
NS
Older Child
4-2-1 rule
Holliday & Segar method
Daily Electrolyte Requirements
Na 2-3 mEq /kg/day day 2-3
K 1-2 mEq /kg/day day 3-4
Cl 2-3 mEq /kg/day
Ca 20-100 mg/kg/day day 1
* 1 mEq = 1 mmol
Glucose Requirements
term and preterm infants : 5 - 6 mg/kg/min
goal: maintain normoglycemia 40 - 120 mg/dl
D10W 60-80 ml/kg/day >1kg infants
D5W 100 ml/kg/day <1kg infants
Perioperative Fluid Management
3 Phases
1. Maintenance Fluid Replacement
2. Replacement of Preop Deficit
3. Replacement of Ongoing Losses
Perioperative Fluid Management
Maintenance Fluid Replacement
4 - 2 -1 rule WEIGHT FLUID
0 - 10 kg 4 ml/kg/hr
+
10 - 20 kg 2 ml/kg/hr
+
> 20 kg 1 ml/kg/hr
Perioperative Fluid Management
Preoperative Deficit
DEHYDRATION
MILD (1-5 %) history of vomiting or diarrhrea urine output (1st)
MODERATE (6-10%) skin turgor sunken eyes and fontanelles weight loss dry mucous membranes lethargic
Perioperative Fluid Management
Preoperative Deficit
SEVERE (11-15%) cardiovascular instability BP mottled skin tachycardia anuria sensory changes
20% coma shock
Perioperative Fluid Management
Preoperative Deficit Therapy
Components:
1) dehydration severity Hx and PE
electrolyte values
serum tonicity
2) type of dehydration isotonic hypotonic hypertonic
Perioperative Fluid Management
Preoperative Deficit Therapy
3) replacement of deficit
• goal: restore CV, CNS and renal
function
• monitor adequacy based on response
clinical condition
urine output and urine specific gravity
vital signs
Perioperative Fluid Management
Estimated Preop Fluid Deficit
number of fasting hrs x maintenance fluids
infuse 1/2 on the first hr
infuse 1/4 on the 2nd hr
infuse 1/4 on the 3rd hr
Perioperative Fluid ManagementChoice of Fluids
Isotonic Crystalloids
• generally the most appropriate for preop
and intraop deficits
Hypotonic Fluids
• can cause significant hyponatremia
Perioperative Fluid Management
Lactated Ringers (LR)
reasonable for maintenance fluids
less expensive than other BSS
provide Na and K
avoid infusion with blood due to calcium content
Perioperative Fluid Management
Normal Saline (NS)
higher Na content (154)
preferred in patients high risk for cerebral edema
prolonged infusion can lead to :
hypernatremia
hyperchloremia
metabolic acidosis
Perioperative Fluid Management Composition of IV Crystalloid Solution
SOLUTION pH Osm Gluc Na K CL Lact Ca
mg/dl mmol/L
D5 5.0 253 500 -- -- -- -- --
LR 6.7 273 -- 130 4 109 28 3
D5 LR 5.3 527 500 130 4 109 28 3
D5 0.22% NSS 4.4 330 500 38.5 -- -- -- --
D5 0.45% NSS 4.2 407 500 77 -- 77 -- --
0.9% NSS 5.7 308 -- 154 -- 154 -- --
Normosol R 7.4 295 -- 140 5 98 acetate 27 -- gluconate 23
Stoelting RK: Pharmacology and Physiology in Anesthetic Practice, ed 2, Philadelphia 1991, JB Lippincott
Perioperative Fluid Management Composition of Colloid Solutions
Na Cl Osm
5% Albumin 145 100 330 mOsm/L
Hespan 154 154 308 mOsm/L
Hextend 143 124 307 mOsm/L
Is intraoperative
glucose necessary?
Perioperative Fluid Management Intraoperative Glucose Administration
Effects :
intraop hyperglycemia
hyperosmolality
osmotic diuresis
worsen neurologic outcome during cerebral
ischemia
Perioperative Fluid Management Intraoperative Glucose Administration
Exceptions : patients at risk for hypoglycemia
• neonates and young infants
• debilitated patients with chronic illness
• patients on parenteral nutrition
• neonates of diabetic mothers
• Beckwith-Wiedeman syndrome
• nesidioblastosis
Perioperative Fluid Management Intraoperative Glucose Administration
Existing infusions of dextrose-containing fluid
may be continued at a reduced rate (50% of
maintenance) to compensate the effect of surgical
stress on glucose control
Perioperative Fluid Management
1) Real Losses
blood loss insensible losses
urine output drainage from various sites
2) 3rd Space Loss
trauma peritonitis
burns upper GI drainage
Replacement of Ongoing Losses
Perioperative Fluid ManagementReplacement of Ongoing Losses
Degree of Additional Fluid Tissue Trauma Required
Minimal Incision 3-5 cc/kg/hr
Moderate Incision 5-10 cc/kg/hr with viscus exposure
Large Incision 8-20 cc/kg/hr with bowel exposure
Perioperative Fluid ManagementReplacement of Ongoing Losses
EBL Replacement
• crystalloid (3:1 ratio) 3 cc / 1 cc blood lost
• colloid solution (1:1 ratio) 1 cc / 1 cc blood lost
• blood products (1:1 ratio) 1 cc / 1cc blood lost
Perioperative Fluid ManagementReplacement of Ongoing Losses
Albumin
• 25 % and 5% solutions
• pooled from human donors
• no ABO testing or blood filter required
• remains expensive
• in short supply
Is albumin risk-free?
Perioperative Fluid ManagementComposition of Colloid Solution
New Zealand : albumin may be related to Creutz-Jacob
disease (CJD) or prion disease with long incubation period
(>5-10 yrs)
processing of human albumin does not destroy the prions
no blood screening for prion diseases
Perioperative Fluid ManagementReplacement of Ongoing Losses
Determinants of Blood Transfusion
1) Estimated Blood Volume
2) Preoperative Hematocrit
3) Co-existing Illness
Perioperative Fluid ManagementReplacement of Ongoing Losses
Estimated Blood Volume
Premature Neonates 95 -100 ml /kg
Full Term Neonates 85-90 ml / kg
Infants 80 ml / kg
Adults 75 ml / kg (male)
65 ml / kg (female)
Perioperative Fluid ManagementReplacement of Ongoing Losses
Guidelines for Pediatric Normal & Acceptable Hematocrit
NORMAL (x) ACCEPTABLE
premature 40-45 (45) 35
newborn 45-65 (54) 30-35
3 months 30-42 (36) 25
1 year 34-42 (38) 20-25
6 years 35-43 (38) 20-25
Perioperative Fluid ManagementBlood Product Replacement
Normal Hematocrit
Hct within 2 standard deviations for age
Acceptable Hematocrit
Hct that is tolerated by infants and children without
the need for blood transfusion
Perioperative Fluid ManagementBlood Product Replacement
Allowable Blood Loss (ABL)
Hct patient - Hct target X EBV
Hct patient
Perioperative Fluid ManagementBlood Product Replacement
PRBC
10 cc/kg will the hgb by 3 gm/dl and hct by 10%
(adult:1 unit will the hgb by 1 gm/dl and hct by 2-3%)
Platelets and FFP 10-15 ml/kg
given when EBL > 1-2 x the patient’s blood volume
1 unit / 10 kg raises the platelet count by ~ 50,000/uL
Cryoprecipitate 1 unit/10 kg
SUMMARY
Total Intraoperative Fluid Replacement
MF + EFD + ISL + EBL
MF : Maintenance Fluid
EFD : Estimated Preop Fluid Deficit
ISL : Insensible Losses
EBL : Estimated Blood Loss
Summary
Brief Procedures ( myringotomy, PET)
replacement may be unnecessary
1-2 hr Procedures
IV placement after inhalation induction
replace 10-20 cc/kg + EBL in 1st hour
Longer and Complex Procedures
4-2-1 rule
acute intravascular loss: 10-20 cc/kg LR / NS
Summary
Meticulous fluid management is required in pediatric
patients due to limited margin of error
Liberalization of fasting guidelines compatible with
safety limits preop deficit
Crystalloid solution is the first choice to restore
intravascular volume
Summary
Tranfusion trigger points
preop hematocrit and hemodynamics
co-existing medical problems
potential for further blood loss
25% decrease in EBV
Limit glucose-containing solutions for patients at
risk for hypoglycemia