Neonatal

Question 1

What are some neonatal concerns?

Answer 1

• Immaturity of organ systems
• high metabolic rate
• large ratio of body surface area to weight
• ease of miscalculating a drug dose
• nominal amounts of air in lines can be catastrophic

Question 2

What is the timeline for fetal development?

Answer 2

• 1st trimester:
  
  • organogenesis- within 8 wks of conception
  • injury or stress can cause abnormal organogenesis
• 2nd trimester:
  
  • Organ function
  • injury or stress can cause abnormal functional dev of organs
• 3rd trimester
  
  • muscle and fat are gained
  • injury or stress can cause smaller organs and reduced muscle or fat mass
• Extrauterine life is possible after ~22-24 wks

Question 3

How do the lungs develop?

Answer 3

• Lung development begins in utero at about 4 wks but lungs are functionally immature until term
• Growth occurs in 5 stages:
  
  • embryonic
  • pseudoglandular
  • canalicular
  • saccular
  • alveolar
• Growth of parenchyma and surfactant system occurs during the saccular phase from wk 24-40
  
  • 36 wks is magic # for surfactant
• maturation and expansion of alveoli occur during the alveolar period which begins near term and coninues to mature through adulthood
  
  • 24 mil at birth
  • 300 mil as adult

Question 4

What is persistent fetal circulation?

Primary cause?

Initial tx?

other treatment

Answer 4

• AKA Persistent pulmonary hypertension of the newborn
• PA pressures abnormally elevated causing the DA and FO to remain open or re-open
  
  • leads to hypoxia d/t R-L shunting
• Primary cause: hypoxia and acidosis with concurrent inflammatory mediators
  
  • severe birth asphyxia
  • meconium aspiration
  • sepsis
  • congenital diaphragmatic hernia
  • mom’s use of NSAIDS
  • idiopathic
• Initial Treatment
  
  • optimal oxygenation (PAO2 60-100)
  • correct stressors (hypoglycemia or polycythemia)
• Other tx
  
  • surfactant
  • inhaled nitric oxide
  • HFOV
  • ECMO

Question 5

What happens with the umbilical cord clamping at birth?

What causes the functional closure of the ductus arteriosis?

How might this differ in a preterm infant?

Answer 5

• umbilical cord clamping:
  
  • SVR increases
  • left atrial pressure increases
  • flow through FO ceases
• DA functionally closes due to increase in PaO2 > 60
• A preterm infant DA may remain open for several weeks and cause hemodynamic instability
  
  • treated with prostaglandin inhibitor (indomethacin) or surgical ligation

Question 6

What is the APGAR scoring and how is it done?

Answer 6

• 5 signs measured in the newborn at 1 min and 5 minutes after delivery
  
  • HR and resp effort are most important, color least
  • HR <100 bpm generally signifies arterial hypoxemia
• Scoring:
  
  • 0-2: severe asphyxia
  • 3-4: moderate asphyxia
  • 5-7: mild asphyxia
  • 7-9: no asphyxia
• Score 3or less, follow NRP algorithm

Question 7

Why do healthy neonates have cyanosis at 1 minute?

What is the most common cause of persistent cyanosis?

Answer 7

• Healthy neonates still have cyanosis at 1 min d/t peripheral vasoconstriction in response to cold ambient temps (acrocyanosis)
• Persistent cyanosis most likely caused by acidosis and pulmonary vasoconstriction

Question 8

What is the NRP algorithm?

Answer 8

Question 9

How is a newborn/neonatal assessment done?

General

airway

Answer 9

• Accurate weight is essential!
• Overall appearance:
  
  • skin color, mucous membranes
  • looking for acrocyanosis
  • central cyanosis warrants investigation
• Airway:
  
  • tongue size/mobility
  • chin (retrognathia)
  • nasal patency/discharge
  • intact hard/soft palate
  • teeth?
    *

Question 10

Newborn/neonatal assessment:

heart and lungs

neuro

back

musculoskeletal

Answer 10

• Heart and lungs:
  
  • tachypnea
  • flaring
  • grunting
  • retractions
  • respirations may be “regularly irregular” (pauses should be <20 sec)
  • murmors are common, assess pulses
• Neuro
  
  • posture
  • muscle tone
  • sz
  • head control
  • quality of cry
  • fontanelles
• Back
  
  • spinal contour
  • presence of cysts, sinuses, dimples, tufts of hair
• musculoskeletal
  
  • normal resting position for an infant is inward flexion of upper and lower extremities

Question 11

What labs are relevent during a newborn/neonatal assessment?

Answer 11

• POC glucose
• CBC or HCT
• blood type
• Coombs
• bilirubin

Question 12

What is important regarding fluid management in the neonate?

What is newborn fluid requirement?

Answer 12

• Amount of incensible water losses are inversely porportional to gestational age
  
  • higher skin permeability, higher ratio of body surface area to weight and higher metabolic demand
  • radiant warmers and phototherapy increase insensible losses
• Neonatal kidneys are unable to excrete large amounts of excess water or electrolytes
• Newborn daily fluid requirement is 70 ml/kg/day and gradually increases throughout first week
  
  • use 10% glucose for maintenance but NOT for replacement

Question 13

What is important regarding blood transfusion for neonates?

Answer 13

• There is weak expression of ABO antigens at birth so crossmatching is not always needed
• Transfused blood has more hgb A for better release of O2 to tissues
• There is risk of transfusion assoc graft versus host
  
  • give leukoreduced, irradiated blood
  • the radiation destroys lymphocytes
• High risk ionized hypocalcemia with FFP
  
  • decreased ability to mobilize calcium and metabolize citrate
  • monitor ionized calcium and prepare to replace
  • Give calcium gluconate if administering through PIV

Question 14

Venous access:

common sites

site for venous cutdown

common site for central lines

Answer 14

• Peripheral:
  
  • dorsum of hand
  • AC
  • dorsum of foot
  • scalp
• Venous cutdowns: saphenous
• Central lines:
  
  • IJ
  • subclavian
  • femoral
  • PICC lines in axillary vein

Question 15

Vascular access via umbilical vein:

how is it done

complications

length of use

contraindications

Answer 15

• A small amount of the cord is cut and umbilical tape is applied to stop the bleeding.
  
  • one thin walled umbilical vein and two smaller, thick walled arteries can be seen and catheterized using sterile technique
• Complications:
  
  • infection
  • bleeding
  • hemorrhage
  • perforation of vessel
  • thrombosis with distal embolization
  • ischemia or infarction of lower extremities, bowel, orkidney
  • arrhythmia if catheter is in the heart
  • air embolus
  • accidental placement in portal vein- get Xray
• Umbilical vein may remain patent for up to two weeks after birth and can be used in an emergency
• Contraindications:
  
  • omphalocele
  • gastroschesis
  • peritonitis

Question 16

Arterial access in neonate:

umbilical artery catheter tip location

considerations

Answer 16

• The tip of the catheter should be at or just above the level of the aortic bifurcation and below the level of the renal arteries (L2)
• Peripheral a-line whould be inserted and umbilical removed once pt is stable
• flush gently to prevent cerebral or cardiac emboli
• all arterial catheters have the potential to cause distal thromboembolic disease

Question 17

How can arterial access help assess pulmonary hypertension and right to left shunting?

Answer 17

• Preductal and postductal oxygenation should be measured to assess right-left shunting
  
  • shunting through DA is suggested if the preductal PaO2 is 15-20 mm Hg higher than the postductal PaO2
• Shunting at the FO will decrease the predicted value of the preductal PaO2 and will not produce a gradient compared with postductal PaO2
• Preductal SaO2 reflects cerebral oxygenation
• Right radial a-line: Preductal
• Umbilical a-line: Postductal
  *

Question 18

Pharm reminders and pearls. Good luck

Versed and opioids

morphine

remi

propofol

Answer 18

• Versed and opioids combined in neonates can lead to severe hypotension- titrate carefully
• Morphine clearance is directly correlated with gestational age; reduce how much you give it
• Remi has similar PK to older children making it a reliable choice for an intra-op opioid
• Propofol elimination varies in neonates and preterm infants; may see longer half times

Question 19

Pharm reminders and pearls

SCH

NDNMB

Vec

cisatracurium

Answer 19

• Sch dose is increased at 3 mg/kg- pretreatment with atropine required
• NDNMB have significan variability and unpredictability, titrate carefully
  
  • neonates ALWAYS need reversal
• Vec is considered “long acting” in infants d/t liver immaturity
• Cisatracurium produces reliable recovery d/t hoffman elimination; laudanosine can decrease sz threshold

Question 20

What are some urgent problems at time of birth?

Answer 20

• meconium aspiration
• choanal stenosis and atresia
• diaphragmatic hernia
• hypovolemia
• hypoglycemia
• tracheoesophageal fistula
• laryngeal anomalies

Question 21

Retinopathy of prematurity:

What can it lead to?

Cause?

Pathogenesis?

Answer 21

• ROP can lead to blindness if left uncorrected
  
  • incidence inversely proportional to gestational age
• Causes (association)
  
  • exact cause unknown
  • prematurity
  • low birth weight
  • supplemental O2 therapy
  • postnatal hypotension
  • use of surfactant or inotrope
  • need for mech ventilation
• Pathogenesis
  
  • starts with O2- induced retinal vasoconstriction and endothelial cell death
  • followed by unchecked neovascularization from angiogenic factors (VEGF)
    
    • these factors do not respond to normal regulation d/t immaturity

Question 22

ROP:

treatment

What should you avoid?

Answer 22

• Treatment
  
  • cryotherapy
  • laser photocoagulation
  • scleral buckling surgery
  • vitrectomy
• Avoid:
  
  • hyperoxia
  • target SpO2 91-95%

Question 23

What is Subgaleal hemmorhage?

incidence

Sx

Answer 23

• Occurs in 1.5-30 per 10,000 births
• Venous bleeding btw the aponeurosis and the pariosteium and can increase considerably in size over firs hours to days of life
• Symptoms
  
  • a large boggy, shifting collection of fluid over the cranial surface unrestricted by suture lines
  • may extend to neck and behind ears, lifting ears forward
• This subaponeurotic space is large, can have hypovolemia d/t bleeding
  
  • may see hyperbilirubinemia after RBC breakdown occurs
• may remain asymptomatic and be observed for 24-48 hours

Question 24

What is Meconium?

What causes aspiration?

When does it usually occur?

Answer 24

• Meconium is the breakdown product of the swallowed amniotic fluid, GI cells, and secretions
• Meconium is usually present after 34 weeks gestation
  
  • intrauterine arterial hypoxemia can result in increased gut motility and defecation
• Fetal distress (arterial hypoxemia) causes gasping and the fetus can inhale the meconium into the lungs
  
  • Birth within 24 hr of aspiration, the meconium is in major airways and is distributed through lungs with breathing
• obstruction in small airways causes Vent/perf mismatch
  
  • RR can be > 100 bpm
  • lung compliance decreases

Question 25

What can be seen in a severe case of meconium aspiration?

Answer 25

• PHTN and R-to-L shunting through patent FO and DA leading to hypoxemia
• Risk of pneumothorax

Question 26

Meconium aspiration:

Historic tx?

current tx?

Answer 26

• Historic tx:
  
  • ETT immediately after delivery with sxn of meconium from airways
• Current tx:
  
  • more conservative
  • no routine oropharyngeal or nasopharyngeal sxn for infants born with eithe clear or meconium stained amniotic fluid
  • ETT sxn is indicated for nonvigorous meconium-stained newborns
• If meconium is present:
  
  • 1st orally suction, if vigorous nothing further req
  • If still depressed, intubate and suction, if vigorous, extubate after sxn and re-intubate
    
    • if not vivorous, keep tube and move to PPV

Question 27

Respiratory distress syndrome:

Primary cause and other causes?

Sx

Tx

long term problems

Answer 27

• Primary cause: lack of surfactant,
  
  • decreased number of branching airways and alveoli
  • atelectasis
  • impaired gas exchange
  • hypoxemia
  • poor lung compliance and propensity for aveolar collapse
• Incidence inverely proportional to gestational age & birth weight
• Sx:
  
  • tachypnea
  • grunting
  • retractions
  • flaring
• Tx: Surfactant via ETT
• Long term problems: bronchopulmonary dysplasia

Question 28

Anesthesia consideration for a neonate with respiratory distress syndrome

Answer 28

Limit hypoxemia while avoiding hyperoxia

follow ABGs

Question 29

Bronchopulmonary dysplasia:

What is it?

Sx

Tx

Answer 29

• Chronic lung disease of infancy
  
  • usually occurs in patients who were born premature and had extensive mechanical ventilation and high FiO2
  • the lungs are hyperinflated
• Sx:
  
  • intercostal retractions
  • nasal flaring
  • wheesing
  • hypercapnia
  • hypoxia
• Tx:
  
  • adequate caloric intake
  • resp support (mech ventilation, CPAP) PRN
  • diuretics and bronchodilators PRN

Question 30

Laryngomalacia/bronchomalacia:

What is it?

Answer 30

• Excessive flaccidity of the laryngeal structures, prone to airway collapse
• Can be congenital or acquired
  
  • laryngomalacia mor often congenital >85%
  • bronchomalacia more likely sequelae of prolonged NICU admission
• Stridor present at birth

Question 31

What are vascular rings?

Answer 31

• anomalies of the aorta that may compress the trachea
  
  • produce insp and exp obstruction
  • may be difficult to advance a tracheal tube beyond obstruction
• Exit procedure may be done where they do partial delivery but keep baby hooked up to placenta so it can continue to get oxygen