Resuscitation, Stabilization, & Thermoregulation

RNC Review

Objectives

� Recognize and understand fetal circulation� Identify physiologic changes that must occur at birth to

lead to a successful transition� Identify the sequence of steps of NRP� Recognize early signs of compromise and describe how

to best manage these patients� Articulate the importance of thermoregulation and risk

factors for hypothermia for the newborn baby

Complexity of the Fetal Circulation

� Differences between fetal circulation vs. newborn circulation○ Placenta (low resistance organ) serves as organ

oxygenating fetus vs. lungs○ Fluid filled gas exchange (lungs are a high resistance

organ) vs. air exchange○ Fetal shunts are open: ductus venosus, ductus

arteriosis, and foramen ovale

Fetal Shunts

� Ductus Venosus ○ UV to IVC (remember UV blood is oxygenated/red blood)○ “Shortcut” to get oxygenated blood to the heart and out to the rest

of the body� Ductus Arteriosus

○ PA to proximal descending aorta○ Shunts deoxygenated/blue blood from the RV, bypassing the fluid

filled lungs, to the lower extremities and out ○ Allows deoxygenated blood to leave fetus via UAs, back to the

placenta to get more oxygen� PFO

○ Shunt between atria ○ RA oxygenated blood to LV, out aorta, and to the body

� All shunts get the most highly oxygenated blood from the placenta to where it is needed most: the fetal brain and heart!

The Changes Needed for Successful Transition

Cord is cut; placenta is no longer part of the circulation….now what?

� UAs & UV will constrict� SVR increases due to removal of this low resistance

organ� Left side of the heart now has an increased workload� LV pressures rise and RV pressures decrease� Pressure changes lead to functional closure of the fetal

shunts○ Bonus: what would happen if these shunts didn’t

close?

The Changes Needed for Successful Transition

Changes in Ventilation

We love that first big cry!

� Breathing fills lungs with air (not fluid)� Alveoli fluid is reabsorbed into the pulmonary lymphatics� Remember..oxygen is a vasodilator: increased PaO2

leads to pulmonary vessels dilating, thus decreasing resistance to blood flow

Path of least resistance, always!

� Each breath should contribute this process, improving FRC and lung compliance=pink baby!

Newborn Circulation

Further Considerations During Transition

� Maternal history○ Meds, chronic illness etc.

� L&D○ Delivery mode, need for assistance○ Fetal distress

� Resuscitation measures needed

NRP Key Points

� Only about 10% of newborns require some kind of assistance

� Only 1% need major resuscitative intervention� Most importantly...ventilate!� Prolonged inadequate perfusion can lead to brain and

other organ damage, or even death� Primary apnea will improve with tactile stimulation vs

secondary apnea (continued decreasing HR and now decreasing BP too) cannot be improved with stim, but needs assisted ventilation

� PPV during secondary apnea should improve HR� Review antepartum and intrapartum risk

factors...ANTICIPATE!

NRP Key Points

� Every birth must have 1 person whose only responsibility if the baby and they must be capable of initiating resuscitation

� If resuscitation is anticipated, more staff who can complete the resuscitation should be present in the DR before the birth occurs

� Remember, 30 seconds to look for a response for each step of NRP

� Teamwork makes the dream work and effective communication

� Initially: ○ Provide warmth○ Position head and clear airway as needed○ Dry and stim

Review the Steps….

NRP Review: MR SOPA

M - mask

R - reposition the head to open the airway

S - suction mouth then nose *1 before 2*

O - open mouth and lift jaw forward

P - gradually increase pressure every few breaths until you note chest rise

A - artificial airway

NRP: Ventilation

Intubation consideration:

� Meconium aspiration� PPV without improvement, after considering MR SOPA� Chest compressions� Special considerations: prematurity, congenital

malformations, surfactant replacement

NRP: Chest Compressions

� HR < 60 despite 30 seconds of effective PPV� 2-finger technique� Thumb technique: often more effective � Compress to ⅓ the diameter of the chest� Rate of 90 bpm or 1 breath to every third compression

Stayin’ Alive

NRP Review

So how did that resuscitation go?

Let’s score!

NRP: Ventilation

Tube size:

NRP Review: Apgar

Targeted Oxygen Saturation: What is the Significance of Pre-ductal Saturation?

Targeted Preductal Sp02

1 min 60-65%

2 min 65-70%

3 min 70-75%

4 min 75-80%

5 min 80-85%

10 min 85-95%

18

19

88

72

Why Right

Hand??

Thermoregulation

Consider a newborn’s large surface area to their body mass ratio:

3x surface area of an adult!

� Decreased subcutaneous fat and glycogen stores� Decreased muscle mass� Thin skin� Cold environment?

Thermoregulation

� A primary vital sign affecting their ABCs� Warm & dry!� Skin to skin if appropriate and safe

Thermoregulation

Why is it so important?

Reduce O2 use

Maximize metabolic efficiency

Reduce calorie expenditure

Thermoregulation

Neutral Thermal Temperature: Minimize work!

� Minimal metabolic rate� Minimal oxygen consumption

Neutral Thermal Environment: ambient temperature around the baby that helps maintain the neutral thermal temperature

Thermoregulation

Ranges of Core Temperature:

� Normal: 36.5-37.3� Cold Stress: 36-36.4� Moderate hypothermia: 32-35.9� Severe hypothermia: <32

Thermoregulation

Physiological response to hypothermia

� Hypothalamus activates norepinephrine ->pulmonary and peripheral vasoconstriction and increased PVR

Thermoregulation

How do they maintain normothermia?

Metabolic process

Voluntary muscle activity

Peripheral vasoconstriction

Nonshivering thermogenesis: brown fat

Thermoregulation

More on brown fat

� Energy source� Initiated in hypothalamus: norepinephrine release� Metabolized to generate heat: uses oxygen and glucose� Used to generate heat instead of shivering (impossible or

not effective)� Cannot be replaced once used� Term infants: 4-10% of adipose

○ Doesn’t form until 26-30 weeks gestation� Last usually 3-6 months of age unless cold stressed (less

longevity)

Thermoregulation

Provide warm, dry environment

Consider delaying bath

Avoid placing beds by drafty doors/windows

Consider hat/clothing, warm blankets

Skin to skin

Servo control

Thermoregulation

Hypothermia is preventable!

It affects morbidity and mortality.

Maintaining normothermia is critical!