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Neonatal Pathophysiology > Renal > Flashcards

Flashcards in Renal Deck (197)
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121

What lab work is indicated for the evaluation of renal failure?

1) CBC with diff & plt ( r/o sepsis; r/o thrombocytopenia)
2) blood culture (sepsis is often the cause of ARF/AKI)
3) therapeutic drug monitoring (watch abx levels closely; if creatinine is increased, decreased frequency, NOT dose)
4) UA (evaluate for hematuria)

122

What is the risk with taping an indwelling cath to the thigh of a male infant?

may cause damage to posterior urethra; can cause strictures

123

How should hematuria be interpreted?

- blood on urine dipstick may be r/t PRBC tx w/i 3d
- UA will determine if it is true blood or hemoglobin (through microanalysis)

124

What can be interpreted as evidence of tubular damage in a UA?

- presence of casts, tubular cells and protein

125

What are urinary casts?

urinary casts are formed in distal convoluted tubule or collecting duct

126

How should the protein result be interpreted from a UA?

trace + 1 is acceptable in PT; should not occur with FT

127

What is BUN?

- non specific marker of ARF/AKI
- reflects accumulation of nitrogenous wastes
- reflects dietary intake of protein
- reflects liver's ability to synthesize urea
(can be as high as 50 in an otherwise healthy baby)

128

What is creatinine?

- specific marker of ARF/AKI

129

How should creatinine values be interpreted?

- needs serial monitoring
- in 1st week of life, may reflect maternal creatinine
- concerning if serum creatinine levels don't fall within a week after birth
- if > 1 mg/dL in FT
- if > 1.5 mg/dL in PT
- if level rising by 0.2 mg/kg/d
- if creatinine doubles, it indicates that 50% of renal function has been lost

130

What is the fractional excretion of Na in urine?

a measurement of tubular function
- not helpful in PT (nephrogenesis is not complete or if patient was recently given lasix)

131

How should the results of fractional excretion of Na in urine be interpreted?

excessive loss of Na indicates tubular damage; differentiates between prerenal and intrinsic renal failure in infants > 32-34 weeks GA
- prerenal: < 2.5%
- intrinsic: > 2.5-3%

132

What is the calculation for fractional excretion of Na in urine?

(urine Na x serum Cr) / (urine Cr x Serum Na)

133

What is the metabolic presentation of the neonate in renal failure?

1) hyponatremia
2) hyperkalemia
3) hypocalcemia
4) hyperphosphatemia
5) metabolic acidosis

134

Why is the neonate in renal failure hyponatremic?

d/t decreased UOP and fluid retention; hypoNa is dilutional

135

What treatment is indicated for the neonate with dilutional hyponatremia in renal failure?

decreased IVF to insensible H2O (about 30mL in FT/ 50-100 in PT) + UOP

136

What can occur with high output renal failure?

hypoNa
- occurs with both oliguric and nonoliguric ARF/AKI
- starts when BUN and Cr begin to decrease
- lasts 24-48h
- can be a good sign

137

What treatment is indicated for serum Na close to 120 and adequate UOP?

- give 10mL/kg infusion of NS over 30-60 min

138

What treatment is indicated for serum Na <120?

* dangerous level, may result in sz
- in an emergency, consider "hot salts" (3% Na, osmolarity 1.025 mOsm/L); can cause intracranial fluid shifts

139

What is the course of treatment for an infant that is not seizing and Na is > 120?

it is best to correct slowly over 24-48 hours
- add Na to IVF (1-3 mEq/kg)
- do NOT increase serum Na more than 8 mEq/L in 24h

140

What is the spot Na urine calculation?

to determine Na losses in urine
(urine Na x mL UOP in 24h) / wt in g
* then give half of the value for 24h

141

What is the formula to correct serum Na?

wt in kg x 0.6 x (CD-CA)= dose in mEq of Na
Concentration desired- concentration actual

* usually only half of this amount is given over 12-24 hours

142

What actions are indicated for hyperkalemic patient?

1) remove all K from IVF
2) give 10% CaGlu to protect heart if EKG ∆ are noted
100-200mg/kg/d over 10-30min
(never through UA)

143

What are immediate treatments to drive K from the intravascular serum?

1) 1/2 strength NaHCO3
2) albulterol
3) insulin/glucose gtt

144

How should 1/2 NaHCO3 be administered?

1-2 mEq over 10-30min (rapid infusion may increase risk of IVH)
- onset of action is 5-10min

145

How does albuterol affect serum K?

- adrenergic agonist increases plasma insulin concentration (helping to shift K intracellularly)
- lowers K by 0.5-1.5 mEq/L
- Onset of action is minimum of 15 min
- duration of action is 2-3hours

146

How does insulin affect serum K?

- co transports K into cells temporarily
- continuous gtt 0.1- 0.2 U/kg/h
- glucose infusion 0.5/kg/h
* follow blood glucoses Q 15-30 min

147

What measures can rid serum of excess K?

1) lasix
2) kayexalate OG/NG/rectally

148

What are the indications for lasix administration?

renal fx must be adequate
- give 1mg/kg IV Q12h; onset of action is 5-10min

149

What are the contraindications for kayexalate?

- not to be used in <29 week preterm
- infant with GI problems or poor GI perfusion

150

What is the mechanism of action for kayexalate?

exchanges Na for K; rectally works best