Neonatal ResuscitationTruth and Consequences

Anjali Prasad Parish, MD

Alaska Neonatology Associates, Inc.An affiliate of Pediatrix, Inc.

Objectives

• Review evidence behind recommendations of NRP and need for revisions

• Specific issues not addressed by NRP

• Refresher of simple clues as to why an infant may not be responding to your treatment

Opening Pressure

• Studies done in 1950’s and 60’s using isolated lung preparations from stillborn infants

• Demonstrated an “opening pressure” which has to be exceeded in order to expand the lung

“The collapsed lung of the newborn infantis a solid structure . . .that when it expandsit does so not as in a balloon, but . . . likea lady’s fan.”

Dr. P. N. CoryllosAm. J Obst. And Gyn., 1931

Normal Onset of Respiration

• Reported in Acta Paediatrica in1962; study done in Stockholm, Sweden

• Made 79 attempts to record first breath taken by normal, vaginally delivered term infants; 18 successful and reported

• Placed a facemask and intraesophageal catheter on infants immediately after delivery and before the cord was clamped

Normal Onset of Respiration

• Recorded negative inspiratory pressures as little as -5 to as much as -70 cm H2O

• Demonstrated establishment of “residual volume” in only 7 infants after first breath; unable to demonstrate development of FRC with successive breaths

Pressures of First Breath

Opening Pressure for NRP

• Initial 1-2 breaths delivered should have Pip of 30 cm H2O pressure then Pip should be readjusted to least amount necessary to see visible chest rise

• Same for term and preterm infants

Expansion vs Rupture Pressure

• Published in 1965 in Lancet• Lungs from newly born and stillborn infants were

excised post mortem • Suspended over a water bath and inflated with

fixed increments of air volume until the lung ruptured

• Rupture was determined when extravasated air was seen under the pleura, bubbling seen from hilum, or slow fall in pressure

Filling vs Rupture Pressure

Inactivation of Surfactant?

• Observation that prophylactic surfactant therapay has not yielded better results than rescue therapy

• Even if immediately intubated, infants receiving prophylactic surfactant receive manual ventilation prior to its administration

Researchers Hypothesize

• Does ventilation-induced lung damage occur within seconds?

• Had damage already been done before surfactant was given?

• Fetal lamb studies are shedding new light on these questions

Just a Few Large Breaths

• Researchers in Sweden; Pediatric Research, 1997• Series of 5 two-lamb siblings were randomized

within each pair either to receive or not receive 6 large breaths at birth; all lambs then received cautious ventilation; surfactant was given at 30 minutes of age

• 3 different lambs were given surfactant prior to first breath

Results

• A few large breaths inhibited effect of surfactant on lung mechanics

• Lambs which received surfactant before the first breath received the most benefit from surfactant

Surfactant After Breaths

Surfactant Before Breaths

Manual Ventilation

• Even with manometers, neonatal resuscitation bags provide varying pressures/volumes with every delivered breath

• These variations differ between types of providers as well

Comparison Trial

• Dr. Neil Finer and colleagues; Resuscitation, 49 (3) (2001) p. 299-305

• Compared flow-inflating bag, self-inflating bag, and Neopuff Infant Resuscitator

• Used infant mannikin and compared accuracy of neonatal nurses, NNP’s, neo’s, residents, and RT’s using all 3 devices to deliver target PIP and PEEP

Results

• Anesthesia Bags: RT’s performed the best; only RT’s could consistently deliver PEEP

• Using Neopuff, all groups could consistently delivery PIP and PEEP

• Significant difference between pressure at 1st and 5th second during prolonged 5-s inflations using anesthesia bags vs. Neopuff (median difference of 7.1 cmH20 using bags vs. 0.2 using Neopuff, p<0.001)

Neopuff Infant Resuscitator

• Made by Fisher and Paykel Healthcare

• Pneumatically powered

• Fingertip breath-by-breath resuscitation using either ETT or mask

• Adjustable PIP and PEEP with max PIP protection

• Disposable, single-use T-piece for each pt

Neopuff

Use of Oxygen

• NRP recommends use of 100% oxygen

• Accepted standard of care; no evidence based on trials

• Due to concerns for oxygen toxicity, attention has turned to room air resuscitation

The Resair 2 Study

• Trial conducted in “developing” countries

• Consent obtained after resuscitation based on principles from FDA’s “clinical research on emergency care without the consent of subjects”

• Abstract published in Pediatrics, 1998

The Resair 2 Study

• Unblinded study; asphyxiated infants with BW>999 grams randomized based on birthdate; even date resuscitated with room air, odd with 100% O2

• 609 infants from 10 centers (288 received RA, 321 received O2)

Results

• No differences in heart rate in first 90 seconds of life; however, 25.7% “resuscitation failures” in RA group switched to 100% O2 after 90 seconds; but also 29.8% “failures” in O2 group (failure defined as bradycardia and/or central cyanosis after 90 seconds)

• Time to first cry or first breath was significantly shorter in room air group (by 24 seconds)

Conclusions of Resair 2 Trial

• Asphyxiated newborns can be effectively resuscitated with room air

• Does resuscitation with 100% O2 depress ventilatory drive?

• More studies needed

Apgar Scoring

• Not included in the NRP program• Created by Virginia Apgar • Based on term infants only• Original intent was as “ a practical method of

evaluation of the condition of the newborn infant” at one minute of life

• Original paper focused on how different types of delivery and anesthesia affected the infant at one minute

Method of Apgar Scoring

Factors Which May Affect Apgar Scores

• Gestational Age

• Maternal Medications

• Prenatal Insults

• Resuscitation

• Type of Delivery

Effect of Gestational Age

Who Should Assign an Apgar Score?

• Anyone not performing the resuscitation

• Scores should be assigned at selected intervals

• Retrospectively assigning scores defeats the purpose

Using Apgar Scores to Predict Development of CP

• National Institute of Neurological and Communicative Disorders and Stroke

• 49,000 infants born between 1959-1966 were examined at birth 31,000 followed to 7 years of age

• Apgar score of < or equal to 3 at 1 minute may be a risk factor for cerebral palsy

• Very low late Apgar score was correlated with increase incidence of cerebral palsy

Apgar Scores and CP

Percent CP vs Late Apgar Score

Apgar Scores and CP

• 80% of children with Apgar scores of 0-3 at 10 minutes were free of major handicap at early school age

• 55% of children with CP had Apgar scores of 7-10 at 1 minute of age

• 73% of children with CP had Apgar scores of 7-10 at 5 minutes of age

Endotracheal Intubation

• Initial placement should be to centimeter mark of 6 + weight in kilograms

• Want the tip of tube to be 0.5-1.0 cm above the carina

• Head position can affect position of the tip

• Breath sounds easily transmitted throughout the chest, so CXRay best confirmation

Signs of Misplaced ETT

• Stomach getting larger with ventilation• Louder breath sounds in stomach--sounds can

transmit from the stomach to the lungs• Large airleak when initial tube size selected

appropriately• Decreased breath sounds on left side• Pt’s heart rate and color not improving

Case Number 1

• Pt transferred from an outside NICU for respiratory decompensation and possible need for ECMO

• Had been tried on multiple ventilators, including HFOV

• Could not reduce PCO2 to less than 60• On arrival to was noted to have a large

airleak around the ETT

CXRay

Case 2

• Infant intubated for grunting and retracting• Breath sounds heard equally throughout

chest and over stomach• Equal chest rise• Large stomach despite previous

decompression with OG tube• Infant’s heart rate 100 bpm and baby dusky

pink color

CXRay

In Summary

• Neonatal resuscitation is clearly evolving• Current recommendations are for term infants and

original data did not include preterm infants• Trials are needed but somewhat difficult since no

“gold standard” exists for premature infants• Apgar Scoring not included in NRP because it was

created to compare infants, not govern their resuscitation