Neonatal Flashcards
How long are infants obligate nose breathers?
Up to about 5 months
What is the epiglottis shape of a neonate/infant?
Omega shaped
Stiff
difficult to displaced during laryngoscopy
How do pediatric tongues differ from adult tongues?
Take up a greater volume of the mouth, which makes obstruction more likely and displacement difficult during laryngoscopy
How are pediatric vocal cords positioned?
At an anterior slant
Easy to get the tube stuck in the anterior commissure
If you encounter resistance beyond the vocal cords, this is likely due to:
the cricoid cartilage
What is the narrowest region of the pediatric airway?
Narrowest fixed: Cricoid
Narrowest Dynamic: vocal cords
The vocal cords are technically narrower, but they’re also distensible, so they can get bigger. The cricoid can’t/
What is the narrowest region of the pediatric airway?
Narrowest fixed: Cricoid
Narrowest Dynamic: vocal cords
The vocal cords are technically narrower, but they’re also distensible, so they can get bigger. The cricoid can’t/
What is the oxygen consumption in an adult? An infant?
Adult: 3 ml/kg/min
Infant: 6 ml/kg/min
Which is altered in neonates: alveolar ventilation or tidal volume?
Alveolar ventilation. Their tidal volume is the same as adults (6ml/kg)
Do neonates have a smaller FRC?
No, the volume is technically the same, but oxygen consumption is so much higher that the FRC is rapidly exhausted
What is the rate of alveolar ventilation in a neonate?
130 ml/kg/min
What is the rate of alveolar ventilation in an adult?
60 ml/kg/min
What are Type I muscle fibers?
Slow-twitch muscles that are built for ENDURANCE - resistant to fatigue
What are Type II Muscle fibers?
Fast-twitch muscles that are built for SPEED - they tire easily
What percentage of adult diaphragm muscles are type I?
55%
What percentage of neonatal diaphragm muscles are type I?
25% - they tire out faster
The risk of apnea in neonates is inversely proportional to:
gestational and Post-Conceptual Age (PCA)
What preterm infants should be admitted postoperatively for apnea monitoring?
< 44 Weeks PCA
All patients <66 weeks PCA should be kept for monitoring
Besides caffeine, what can be used to reduce the incidence of apnea in postop neonates?
Theophylline, but it has more toxicity risks
Is neonatal lung compliance higher or lower than adults?
Lung compliance is lower, because there are fewer alveoli
Is neonatal chest wall compliance higher or lower than adults?
Higher. The chest wall is flimsy.
Is closing capacity increased or decreased in neonates?
Increased. Closing capacity overlaps with tidal breathing
What mechanisms help support neonatal FRC?
- Sustained tonic activity of inspiratory muscles
- Narrowing of the glottis during expiration
- Shorter expiratory time coupled with a faster respiratory rate results in PEEP
ALL OF THESE ARE ABOLISHED WITH GENERAL ANESTHESIA
In the newborn, hypoxemia causes:
Apnea
Respiratory drive is not fully developed until about 42-44 weeks PCA
What is the P50 of HgbF?
What is the composition of HgbF?
2 Alpha chains and 2 gamma chains
Why does Hgb F have a higher affinity for oxygen?
The binding site for 2,3-DPG is on the beta chain, which Hgb F doesn’t have. So it can’t bind 2,3-DPG
How long does it take for Hgb F to completely replace Hgb A?
6 months
What is the transfusion trigger in a child < 4 months with cardiopulmonary disease?
13 g/dl
What is the transfusion trigger in a child < 4 months presenting for surgery?
10 g/dl
What is the transfusion dose for neonates?
10-15 ml/kg
A 10ml/kg transfusion should raise Hgb how much?
1-2 g/dl
What is the transfusion trigger in a child > 4 months?
Since most of their Hgb F has been replaced, it’s the same as for everyone else:
> 10 no transfusion
6-9 maybe
< 6 definitely
What are the indications for FFP?
- Emergency reversal of warfarin
- Correction of coagulopathic bleeding with elevated PT/PTT
- Correction of coagulopathic bleeding if > 1 blood volume has been replaced and coags are not easily attainable
What is the dose of FFP in a child?
Same as for blood
10-20 ml/kg
Massive Transfusion is associated with:
- Alkalosis (citrate is metabolized to bicarb in the liver)
- Hypothermia
- Hyperglycemia (stored blood has added dextrose)
- Hypocalcemia
- Hyperkalemia (from hemolysis)
What is the calculation for MABL?
What is a normal Hgb in a neonate?
14-20
What is the EBV of a term neonate?
80-90 ml/kg
What is the EBV in a preterm infant?
90-100 ml/kg
Does the newborn kidney tend to excrete or retain sodium?
Excrete
It lacks developed concentrating mechanisms
Why do neonates have high insensible water loss?
Their BSA to body weight ratio is four times higher than for adults, plus they have thin skin
Do neonates tend to excrete or reabsorb glucose?
Excrete
When does the renal tubule develop full concentrating abilities?
~ 2 years
When does GFR increase to adult levels?
8-24 months
Compared to adults, what three kidney functions are lower in the neonate?
- GFR
- Renal Perfusion Pressure
- Concentrating & Diluting ability
TBW % for a premature neonate is about:
85% of body weight
TBW % for a term infant is about:
75%
TBW % for a child and adult is about:
60%
On a cellular level, why are neonates so sensitive to water loss?
Almost all of their TBW is extracellular, so there’s less intracellular fluid to pull from
Neonates need higher dose of _____ soluble drugs
Water, because they have a higher % water
Will neonates have higher or lower free fractions of protein bound drugs?
Higher, because they have less albumin and alpha 1 glycoproteins for drugs to bind to. This means they are at greater risk of toxicity
Will propofol have a longer or shorter duration of action in the neonate?
Longer, because the duration of action is usually limited by redistribution, but in neonates there’s less fat to redistribute into, so it remains in the plasma longer
When does hepatic clearance of drugs reach adult levels?
About 1 year
Why can’t neonates conjugate bilirubin?
Reduced Glucuronyl Transferase. This means they also can’t metabolize tylenol
When does GFR reach adult levels?
8-24 mos
When does renal tubular concentrating ability reach adult levels?
2 years
Are neonates more or less sensitive to sedatives and hypnotics?
Generally more sensitive, because they have a poorly developed BBB
Is a neonatal MAC higher or lower than an infant MAC?
Lower (BBB)
EXCEPT WITH SEVO
Is a premature MAC higher or lower than a neonatal MAC?
Lower (BBB)
EXCEPT WITH SEVO
What is a normal Sevo MAC in neonates?
3.2%
What is the CO of a newborn?
200ml/kg/min
Should the dose of a water soluble drug increase or decrease in neonates?
Increase
Should the dose of a lipid soluble drug increase or decrease in neonates?
Decrease
Is the dose for succinylcholine higher or lower in neonates?
Higher! They have increased volume of extracellular fluid and their receptors are just as sensitive as adult receptors
Is the dose for nondepolarizing NMBAs higher or lower in neonates?
Its the same, BECAUSE:
their neuromuscular junction is MORE sensitive to nondepolarizers and EQUALLY sensitive to succinylcholine
Are NMBAs lipid or water soluble?
VERY WATER SOLUBLE
This is why they don’t cross barriers well
What is the duration of action of succinylcholine in a neonate?
The same as in an adult
When is bradycardia from succinylcholine most likely to occur?
It may occur after the first dose, but its more likely to occur with subsequent doses
What is the IM dose for succinylcholine in the neonate and infant?
5 mg/kg
What is the IM dose for succinylcholine in the child?
4 mg/kg
Which nondepolarizer can be given IM?
ONLY ROC
What is the IM dose of Rocuronium for children?
1.8 mg/kg
What is the IM dose of Rocuronium for infants?
1 mg/kg
“One for less than one”
How long does it take for IM rocuronium to work?
3-4 minutes!
What are good indicators or readiness for extubation in a neonate?
ToF > 90%
MIF < - 25cmH2O
For every gas EXCEPT sevo, when does MAC peak?
2-3 months
