Peds A&P anesthesia considerations Flashcards
organogenesis
1st 8 gestational weeks
rapid growth during the _____ trimester
2nd
weight increase (both sub-cu and muscular) during the _____ trimester
3rd
preterm
< 37 weeks
term
37-42 weeks
post-term
> 42 weeks
low birth weight (LBW)
< 2,500 grams
very low birth weight (VLBW)
< 1,500 grams
extremely low birth weight (ELBW)
< 1,000 grams
micro-preemie
< 750 grams
babies can be _____, ______, or _______ for gestational age
small (SGA), appropriate (AGA), or large (LGA)
gestational age is assessed by _________, 1st trimester, ultrasound
crown-rump length
gestational age assessed by
1st day of LMP
most accurate assessment of gestational age AFTER birth
Dubowitz score (combo of physical and neurologic characteristics to estimate gestational age)
Dubowitz score physical characteristics
ear, skin, sole of foot, breast tissue, genitalia
Dubowitz score neurologic characteristics measured
tonicity, grasp, moro, sucking, reflexes
growth measurements on ex-preemies:
corrected gestational age (not chronological age)
corrected gestational age on ex-preemies should be used until child is
2 years old
ex: child born at 28 weeks gestation and is now 6 chronological months (24 weeks) old, that same child is
52 post-conceptional weeks
for the 52 post-conceptual week old child, a growth plot for a ________ should be used
3 month old (12 weeks)
failure to thrive (FTT) definition
significant failure to reach average weight for age
FTT causes:
- genetics (parents, chromosomal disorders)
- nutrition (malabsorption syndromes, CF)
- congenital malformations (cardiac, urinary)
- infection
- metabolic/endocrine disorders (hypothyroid)
- prematurity
- malignancy
- bronchopulmonary dysplasia
current age of viability
23 - 24 weeks
at age of viability (23 - 24 wks), lungs have developed gas-exchanging ______ and _______
surface and surfactant
airways:
bronchial tree down to terminal bronchioles formed by the 16th week
alveoli:
present at birth with continued proliferation up to 8 years of age
pulmonary vasculature:
bronchial tree by 16th week, complete at late adolescence
glandular stage (___-___ weeks): segmental airways, vessels, cartilage differentiation in the ______ and ______
7 - 16 weeks
trachea and bronchi
CANALICULAR STAGE (___-___ wks): formation of gas exchanging surface and ______ ______
16 - 24 weeks
surfactant production
surfactant production is by
type II pneumocytes
alveolar stage (___-___ wks): surface area grows quickly, membrane thins, and _______ levels in ______ ______ become indicator of lung maturity
24 weeks to term
surfactant
amniotic fluid
3rd week of gestation: ________ is formed, connects to arterial and venous systems, _____ divides
heart tube
aorta
bronchial arteries develop between ___-___ wks
9 - 12
7th week of gestation ______ ______ in place
fetal circulation
main pulmonary artery goes to ______
lungs
patent ductus arteriosus (PDA) goes to ____
aorta
lungs go to pulmonary veins and then to ______ _____
left atrium
fetal circulation is ______ circuits not ______ like adults
parallel
series
right and left ______ provide systemic flow
ventricles
oxygenated blood from the placenta enters the fetus through the _____ _____
umbilical vein
most of the newly oxygenated blood bypasses the liver via the ____ _____
ductus venosus
and combines with deoxygenated blood in the ______ ______ ______
inferior vena cava
blood then joins deoxygenated blood from the ______ _______ ______ and empties into the right atrium
superior vena cava
since the pressure in the right atrium is larger than the pressure in the left atrium, most blood will be shunted through the ______ _____
foramen ovale (PFO)
some blood does travel from the right atrium to the right ventricle through the pulmonary trunk but most blood bypasses the pulmonary arteries and moves directly to the aorta via the ______ ______
ductus arteriosus (PDA)
deoxygenated blood returns to the placenta via the ______ ______ originating from the internal iliacs near the bladder
umbilical arteries (2)
must know 3 shunts:
- ductus venosus
- PFO
- PDA
transition to air critical event:
1st gasp
huge distention of pressure —> fluid movement out of the _____ —> increasing pulmonary blood flow —> increase in _______ ______
alveoli
pulmonary oxygenation
decreased ______ and increased ______ leads to closure of the foramen ovale and reversal of shunt through ductus arteriosus
PVR
SVR
INCREASED PVR d/t hypoxia and/or acidosis leads to persistent fetal circulation (PFC) with pulmonary HTN and results in _____-_____ _______
right-left (cyanotic) shunting
physiologic right-left shunting occurs for several hours after birth until:
unexpanded regions of lung are ventilated
infant accessory muscles are _____ and ______
weak and ineffective
chest wall is floppy due to high amount of ______, little _______, and poorly developed _______
cartilage, little calcification, and poorly developed musculature
low level of ______ fibers (_____ fibers) leading to easy respiratory fatigue/failure
Type I (slow twitch/marathon fibers)
_____ ______ lowest at infancy, peaks in adolescence, then declines
elastic recoil
elastic recoil is BIG determinant of _____ _____ ______
static lung volume
_____ ____ ______ is low d/t weaker, inefficient inspiratory muscles
total lung capacity (TLC)
_______ ______ ______ is similar on a per kg basis at all ages
functional residual capacity (FRC)
BUT - low _____ _____ puts FRC at 10% predicted instead of near 40% predicted in adults
elastic recoil
NET RESULT of low elastic recoil - apnea leads to a disproportionate low _____ ______ leading to ____ _______
O2 reserve
rapid hypoxemia
reason for rapid desaturation in infants with airway loss
______ ______ cannot be measured in children < 5 years old
closing volume
infants probably have some closed peripheral airways throughout tidal breathing leading to ______ _____ ______
trapped gas volumes
r/t airway dynamics high ______ in newborns, even higher in preemies
resistance
resistance decreases markedly in the _______ airways (_____ generations) around 5 years of age
peripheral airways (> 12th generation)
reason for severe resp impairment in very young children with only minimal airway inflammation (bronchiolitis)
tracheal compliance ____ higher in infants increasing the risk for _____ _____
2x
tracheal collapse
regulation of breathing - _____ is the driver
CO2
increased ______ causes increased Vt and RR
PaCO2
decreased ____, ____, and _____ stress leads to decreased ventilatory drive
decreased BG, Hct, and cold stress
hering-breuer reflex:
lung inflation causes induced apnea (often seen with positive pressure extubation)
periodic breathing:
5 - 10 second pauses followed by bursts of increased breathing
periodic breathing must be differentiated from ______
apnea
apnea is:
prolonged pauses leading to desaturation, bradycardia, and hypotonicity
apnea is common in ______ and can be severe in ______ _____
preemies
extreme preemies
apnea may self resolve or it may require:
tactile stimulation or bag-mask ventilation
apnea can be treated with ________ that increase central ventilation drive, _____ for chest-wall stabilization or _______
theophyllines
CPAP
stimulation
apnea of _______ has HUGE anesthesia implicaitons
prematurity
highest risk at ______ post-conceptual age
< 55 weeks PCA
if premature is < 55 weeks, they must be ______ _______ for ________
admitted post-op for monitoring
example: ex-28 weeker, now 5 months old, presents for hernia repair, admit post-op?
YES but this applies to PRE-TERM INFANTS ONLY
infant O2 consumption is _______
higher than adults
infants increase their alveolar ventilation through ______ _____ ______
increasing respiratory rate
PaO2 is _______ in neonates
decreased
but they compensate with increased _____ _____ ______
O2 carrying capacity
fetal Hgb is _____ of total Hgb
50%
_____ shifted O2 hgb dissociation curve
LEFT
PaO2 gradually ______ throughout childhood, _____ in adolescence, and gradually _______ throughout adulthood
increases
peaks
decreases
wide variation in _____ _____
normal HR
newborn mean HR
120 bpm
1 month old mean HR
160 bpm
mean adolescence HR
75 bpm
6 week - 1 year mean systolic BP
99 mmHg
1 year - 6 years mean SBP
minimal change
> 6 years mean SBP
gradual rise to adult mean
measuring cardiac output (3)
- Fick (O2 extraction) method
- PAC (rarely used d/t shunting)
- DOPPLER ECHOCARDIOGRAPHY
resting CO is ______ that of an adult
2-3x
probably d/t increased _____ _____ and ______ ______
metabolic rate and O2 consumption
increased O2 consumption probably d/t ____ ____
heat loss (relatively larger surface area to body mass)
____ ______ increases with age (EKG)
PR interval
____ _______ increases with age (but > 0.10 always ______)
QRS duration
pathologic
QRS axis ____ at birth
right
QRS axis rotates _____ during 1st month
Left
in utero, large urine volumes make up ____ ______
amniotic fluid
in utero, homeostasis maintained by _____
placenta
at birth, GFR is _____ of adult value - adult value attained by _____ _____
< 30%
2 years
decreased GFR leads to poor excretion of _____, _____, and _____
Na+, H2O, and drugs
_____ poorly reserved leading to physiologic ______
bicarbonate
acidosis
infants can maintain normal _____
BUN
increased BUN signifies _____ _____ or other ______
renal failure
illnesses
kidneys can grow into ______
adulthood
so removed or damaged kidney can lead to ______ of remaining kidney with ______ of total fxn
hypertrophy
takeover
biliary tract is completed at ______ gestation
10 weeks
placental blood goes through _____ _____ bypassing the _____ and to the IVC
ductus venosus
liver
_____ _____ closes soon after birth
ductus venosus
liver function is _____ in newborns
immature (worse in preemies)
at term, glycogen stores are _______, but preemies are at risk of _______
adequate
hypoglycemia
protein synthesis in _______ (a -fetoprotein)
liver
the proteins needed for clotting are _____ for the 1st few days
low (poor clotters, need Vit K)
drug ______ and _______ altered in newborns
metabolism and binding
immature _______ ______ system, less protein
cytochrome P-450
non-hemolytic physiologic hyperbilirubinemia:
increased bilirubin production d/t RBC breakdown and deficient conjugation (immature liver)
worsened by
breast-feeding
other causes:
- Rh/ABO incompatibility
- inherited blood disorders
- infection
- biliary atresia
- stress
treatment:
- can self-resolve
- phototherapy
- exchange transfusion (if extreme)
kernicterus:
encephalopathy d/t increased bilirubin
highest risk for kernicterus
preemies
commonly seen: ______ ______ in preemies and LBWs d/t long term TPN
cholestatic jaundice
preemies tolerate protein loads _____
poorly
at 5-7 wks gestation, GI tract “_____ and _____” into abdominal position
migrates and rotates
duodenal motility matures between ____-____ weeks gestation
29 - 32
GI anomolies
- esophageal atresia
- tracheoesophageal atresia/fistula (TEF)
- intestinal atresia/stenosis
- hirschprung’s
- meckel’s
- omphalocele
- gastroschisis
______ requires neuromuscular coordination that is poorly developed in preemies
swallowing
peristaltic waves are absent in infant’s ____ _____ leading to spitting
lower esophagus
(even in term newborns)
_____ damage leads to inadequate swallowing
CNS
_____ of newborns have reflux for several days
40%
severe cases of reflux:
- persistent vomiting
- failure to thrive
- hematemesis
- anemia
- strictures
GE/reflux can cause ____/______ in preemies
apnea/bradycardia
meconium should be passed in the 1st ______
48 hours
late meconium passage could be d/t:
- ileus
- atresia
- hirschprung’s
- imperforate anus
- cystic fibrosis
NEWBORN NIGHTMARE
meconium aspiration
meconium aspiration causes:
- pneumonia
- PTX
- persistent pulm HTN (PPHN) - failure to convert from fetal circulation resulting in severe hypoxemia, hypercarbia, acidosis
maternal hyperglycemia leads to fetal pancreatic _____ and _____
hypertrophy and hyperplasia
this leads to increased fetal _____
insulin
and the newborn will be ____ and _____ at birth
large and overweight
increased insulin levels at birth cause rapid ________ and must be closely monitored
hypoglycemia
SGAs and preemies are easily hypoglycemic d/t poor _________ and decreased _____ _______
gluconeogenesis
glycogen stores
maintain newborn glucose at
> 40 - 45
can have extreme hypoglycemia without _______
symptoms
hypoglycemia symptoms
jittery, lethargic, seizures
preemies and LBWs also at risk for _______
hyperglycemia
hyperglycemia can cause _____ ______ and ________
cerebral bleeding and infection
avoid by keeping _____ _____ glucose level with pumps
steady state
initial blood volume is dependent on ____ _____
cord clamping
blood volume approx _______ with immediate clamping
80 ml/kg
blood volume approx ________ with immediate clamping in preemies
90 ml/kg
newborn Hgb:
14 - 20 g/dL
(when this drops, physiologic anemia occurs)
newborn Hgb drops to ______ around 3 months and then begins to increase
10 g/dL
greatest Hgb decrease happens in preemies at ______
2 months old
this physiologic anemia is ________ _______ to extrauterine life
normal adjustment
_____ shift of the oxyhemoglobin dissociation d/t increase in 2,3 DPB and replacement with adult Hgb
RIGHT
(anemia tolerated well)
VLBWs may be treated with _______
erythropoietin
normal Hgb from 3 months - 2 years:
12 g/dL
neonates have immature _____ leading to increased risk of ________
WBCs
infection
________ common in preemies
thrombocytopenia
mechanical ventilation and artificial membranes (ECMO) lead to _______
thrombocytopenia
polycythemia (HCT ____) may require partial exchange transfusion d/t decreased ______, increased ___ ______, and _____ _____
Hct > 65%
viscosity
O2 transport
blood flow
newborns have decreased ____ ____ dependent factors
vitamin K
Vit K dependent factors:
II, VII, IX, X
all newborns should receive ____ ____ _____
vitamin K injection
surgery during 1st week without exogenous Vit K can be ___-_____
life-threatening
decreased perinatal mortality has NOT decreased _____ _____
cerebral palsy (CP)
CP predictors:
- congenital anomalies
- decreased placental birth weight
- fetal position
- perinatal asphyxia
malnutrition during the 1st two years of life can cause impaired _______ leading to ______
myelination
handicapping
_____, ______, ______ cause blood brain barrier breakdown leading to neurologic damage
hypoxia, ischemia, edema
developmental milestones may ____
vary
_____ _____ ______ frequently used
Denver Developmental Screening
preemies WILL BE _______
delayed
assess by conceptual age not chronologically
children and adults with CP and/or sensory/motor deficits can have _______ cognitive fxn
NORMAL
drug interactions, hepatic (and renal) fxn and enzyme induction must be considered