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What is the maternal marker used to predict gestational age?

Last menstrual period

When in pregnancy is gestational age most accurate using ultrasound? Why?

1st trimester

They all develop at the same rate initially

Preterm infant definition

Any infant born before the beginning of the 38th week

If baby is born at 37weeks and 5 days= preterm

A preterm infant can be what size

any size


Low birth weight (LBW)

5# 8oz

2500 grams or less


3# 5oz

1500 grams or less

Extremely LBW (ELBW)

2# 3oz

1000 grams or less

Preemie rule

the more preterm the more problems


Mixture of phospholipids and proteins that line the alveoli in the lungs

When does production of surfactant begin?


When does the baby have adequate amounts of surfactant?

34-36 weeks

What are 3 types of surfactant?

L/S (lecithin/sphingomyelin)

PG (phosphatidylglycerol)


Why is surfactant critical (2)?

It lowers the surface tension of the alveoli to keep them inflated in between inspirations.

(With a full term infant the 1st few breaths open up all of the alveoli in the lungs)

What if there is insufficient surfactant (2)?

The alveoli collapses with each expiration and must be re-opened during each subsequent inspirations

Causes the lungs to get stiff, begins the pathology of RDS

Pathophysiology of RDS (3)

Surfactant is constantly being used in the process of breathing

Lungs become stiff and require higher pressures of inspired air for adequate oxygenation to take place (Have to work harder) if not enough surfactant

Higher pressures cause further difficulty during inspiration

Pathophysiology of RDS 2 (4)

Some of the alveoli cannot open and collapse

Areas of hypoxia occur

Pulmonary vasoconstriction occurs causing decreased blood flow to the lungs (pulmonary hypertension) possibly leading to PFC (persistent fetal circulation= ductus arteriosis opening back up --> ↓pH)

Acidosis and alveoli death lead to decrease in production of surfactant (Hyaline Membrane known as RDS)

What are 6 risk factors for RDS?

prematurity rule: more preterm, more likely

IDM = fetal insulin retards cortisol production which is needed for stimulation of surfactant production

more males than females

more white babies than other

Birth asphyxia = low APGAR scores, cord blood showing acidosis, EFM strip showing late decals & ↓ variability

C/S especially w/o labor

What are s/s of RDS? (9)

1. retractions, grunting, nasal flarign
2. tachypnea, RR > 60
3. Tachycardia AR > 160
4. decreased breath sounds, rales
5. cyanosis, pallor, apnea = late signs
6. hypothermia = <97.3/36.3 b/c using cal to breathe, not keep up temp
7. hypoglycemia <35-20 b/c using calories up to stay alive
8. hypotensive
9. hypotonia = poor muscle tone

O2 sat for term infants & preterm infants

term infants = 95-100%
Pre-term infants = 88-92%

pH, PaCO2 & HCO3 levels

pH = 7.35-7.45
PaCO2 = 35-45
HCO3 = 22-26

PaO2 levels (& capillary sample level)

Pa02 80-100
Capillary sample = 50-80

Respiratory buffer system (2)

Resp system: fast, can respond immediately to changes (attempts to compensate)

CO2 when combined with H2O= carbonic acid
(High CO2 decreases pH, Low CO2 increases pH)

Respiratory response to acidosis

Increase respirations to blow off more CO2

Respiratory response to alkalosis

Decrease respirations to retain more CO2

Renal Buffer system (2)

Renal: slow, takes up to 2 days to respond to changes- will attempt to compensate

HCO3- base
(high levels increase pH, low levels decrease pH)

Renal response to acidosis (3)

Reabsorbs HCO3

secretes H+

produce ammonia

Renal response to alkalosis (3)

Excrete HCO3

Decrease H+ secretion

Less ammonia production

Resp Acidosis (3)

pH <7.35

PaCO2 >45

Caused by the accumulation of CO2 b/c of Hypoventilation- which occurs with RDS (in later stages b/c they get tired)

Resp Alkalosis (3)

pH >7.45

PaCO2 <35

Caused by decreased CO2 because of hyperventilation
-Could occur with inappropriate ventilator settings

Metabolic Acidosis (4)

pH <7.35

HCO3 <22

Caused by failure to retain HCO3

RDS- lack of O2 at a cellular level- anaerobic metabolism→ lactate acid produced- HCO3 used up to balance the lactate acid- resulting in a base deficit

Metabolic Alkalosis (3)

pH >7.45

HCO3 >26

Caused by failure to excrete HCO3 or by a decrease in blood acid

Many babies with RDS have what kind of pH imbalances?

metabolic and respiratory acidosis before treatment

ABG interpretation strategy (3)

Attempt to identify causes and correct

Call MD

4 basic components of ventilator settings

FiO2 inspired O2 content

Breaths per min

PIP peak inspiratory pressure (less pressure needed with the healthier baby)

CPAP continued positive airway pressure

Ventilator: RN assists with & what improvements should you expect to see?

Endotracheal tube placement, and monitors for expected improvements:
O2 sat ↑
CO2 indicator
Breath sounds equal and air exchange

How do you confirm proper endotracheal tube placement?


expect improvement in ABGs

5 Potential complications of RDS

PDA = patent ductus arteriosus

IVH intraventricular (brain) hemorrhage (50% <1.5kg)

BPD bronchopulmonary dysplasia (20%)

ROP retinopathy or prematurity (5-10%)

NEC necrotizing enterocolitis (2%)

PC of chestube


Patent Ductus Arteriosus (2)

Increasing incidence with decreasing gestational age

O2 saturation will ↓ b/c unoxygenated blood going into aorta

PDA tx (3)


surgical ligation

Nsaids: indomethacin or ibuprofen

IVH (Intraventricular Hemorrhage) pathophys (2)

Rupture of fragile blood vessels in the germinal matrix around the ventricles in the brain

Associated with hypoxic injury, grade 1-4

6 Presenting s/s IVH


Fontanelle - bulging b/c of bleeding



resp distress

poor muscle tone

Medical tx for IVH (3)


Check with US (serial ultrasounds)

Spinal tap or access device to decrease pressure to prevent brain damage

Nursing care for IVH (2)

-assess head circumference every day of at risk infants

BPD bronchopulmonary dysplasia pathophys (2)

Due to chronic exposure of "high" FiO2 (inspired air) levels and "high" pressure of vent. hurts lung tissue

Inflammation, atelectasis, edema (at alveoli), changes that block healthy gas exchange

3 Presenting s/s of BPD

dx infant @ 36 post conception age (cannot be earlier)

RDS symptoms

Looks anxious

7 Medical tx BPD


O2 nasal cannula

Bronchodilators (to help w/edema)

Diuretics (to help w/edema)


Fluid restrictions

NEVER overfeed these kids, pulmonary edema

Retinopathy of Prematurity (5)

"Vasoproliferative" disease <28wks

Normal development: nasal periphery is vascularized at 32wks, temporal @ 40-44wks

Process is arrested at preterm birth by noxious agents (hypoxia) or stressors (preterm birth)

Process starts again- may be wnl or ablnormal (worst case blindness)

90% resolves spontaneously with little or no visual loss

NEC necrotizing enterocolitis pathophys (3)

Caused by interference of blood flow to GI tracts (going to brain, heart & lungs first) - due to hypoxic incidents

Mucosa invaded by bacteria- cellular death- may perforate bowel- peritonitis

Mortality (25-30%)

8 s/s NEC

increased abdominal girth, distention - measure
decreased/absent bowel sounds
blood in stools (frank or guaiac +)
increased feeding residuals (nothing digested)* or emesis
temp instability

5 Medical tx NEC

gastric suction (to get stomach contents out)
surgery to take out bowel

Nursing care NEC (3)

Assess at risk infants for early s/s each shift


maintaint adequate o2 to fetus/infant

Thermoregulation problems (2)

Premature infants have even lesser ability to maintain their body temp

Neutral thermal environment devices can mask signs of sepsis. Ex. to maintain temp at 37 warmer is at 32, then 33, then 34 → baby is becoming hypothermic (need higher warmer to maintain temp). Always monitor the settings of device

3 Brown fat facts

Production of brown fat starts at 26-28wks

Brown fat requires O2 and glucose to generate heat (which preterms don't have)

It cannot be replenished once used

8 s/s of Inadequate Thermoregulation

axillary temp <36.3 or >36.9 C, <97.6 to >98.4 F
or Abd temp 36-36.5C***
Mottled skin
Resp distress
Hypoglycemia, tremors
Decreased muscle tone
Skin feels cool

Kidneys mature at what week and what is the last function to develop?


Last function to develop is the ability to concentrate or dilute the urine

Normal urine output for a preemie & weighing diapers


so a 2kg preemie= 96ml/day

Weigh dry diaper and record, when wet 1 gram=1ml urine (subtract diaper weight)

Catheters are freq used (w/kidney problems)

Normal hydration assessment (8)

Weight gain is slow and steady- 30grams/day
Mucous membranes moist
Good skin turgor
Urine Output wnl
Fontanelle even with skull
Breath sounds equal and clear
AR, BP wnl
Urine specific gravity 1.005-1.015

Other preemie concerns (4)

Skin is delicate and prone to injury- limit tape, be careful

Infection rate is 3-10x greater, WASH HANDS and instruct others to do the same- do not let infectious people near infant

Best measure to px infection in all newborns is handwashing

Preemie has large nutrition needs
--readiness for feeding and digestion is another story

How to assess if premie ready to nipple (4)

they are able to breathe

RR≤ 60. no higher b/c ↑ risk for aspiration

no retractions, grunting, flaring

able to suck, swallow and have gag reflex

Developmental care of preemie (9)

Need minimal stimulation
Dim lights
Group care
gentle touch
promote self-consoling activities
provide soft objects to grasp
when move- hold extremities in flex fetal position, sheepskin

Postterm infant definition

Infants born after 42wks

Placental aging d/t postterm

decreased o2 delivery to fetus is main concern

Postmaturity syndrome, what would you expect to see & what intrapartal emergency (5)

Postmaturity syndrome = Hypoxia and malnourishment during last weeks

At risk for hypoglycemia-used up all glucose stores

AROM = meconium

EFM = late decels & ↓ variability


SGA infant definition

Wt/Ht/HC under the 10th percentile and infant has had IUGR

congenital anomalies may be present

Seek causative factors - Ex. small parents, Type 1 or 2 DM, mom has HTN

SGA Causative factors (3 categories)

Mom medical = HTN, cardiac condition, renal disease, DM (type 1 or 2), poor nutrition

Mom other = smoking, drug, alcohol use

Pregnancy factors = multiple gestation, placental abnormalities, infections (TORCH)


infections in SGA
T = toxoplasmosis
O = Other
R = Rubella
C = cytomegalovirus
H = Herpes

Care of SGA baby (5)

similar to care of preterm
at risk for hypoglycemia
increased caloric needs
at risk for respiratory problems
at risk for hypothermia (no brown fat)

Definition of LGA baby

Wt/Ht/HC over 90th percentile
often birth wt > 8#14oz

Causative factors of LGA baby (3)

IDM = infant of diabetic mother
large parents
some native american groups

Why are LGA babies at risk for hypoglycemia?

pancreas pumps out a lot of insulin b/c it is used to a lot of glucose coming across the placenta from the mom

LGA infants are a greater risk for what & what are 4 potential birth injuries?

Greater risk for c/s birth

If vag delivery, be alert for birth injuries--
-examine clavicles carefully
-depressed skull fractures
-brachial plexus palsies

What is normal urine spec gravity


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