Neonatal Resuscitation Truth and Consequences

1. Neonatal ResuscitationTruth and Consequences Anjali Prasad Parish, MD Alaska Neonatology Associates, Inc. An affiliate of Pediatrix, Inc.

2. 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

3. 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

4. “The collapsed lung of the newborn infant is a solid structure . . .that when it expands it does so not as in a balloon, but . . . like a lady’s fan.” Dr. P. N. Coryllos Am. J Obst. And Gyn., 1931

5. 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

6. 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

7. Pressures of First Breath

8. 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

9. 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

10. Filling vs Rupture Pressure

11. 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

12. 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

13. 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

14. 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

15. Surfactant After Breaths

16. Surfactant Before Breaths

17. 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

18. 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

19. 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)

20. 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

21. Neopuff

22. 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

23. 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

24. 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)

25. 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)

26. 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

27. 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

28. Method of Apgar Scoring

29. Factors Which May Affect Apgar Scores • Gestational Age • Maternal Medications • Prenatal Insults • Resuscitation • Type of Delivery

30. Effect of Gestational Age

31. Who Should Assign an Apgar Score? • Anyone not performing the resuscitation • Scores should be assigned at selected intervals • Retrospectively assigning scores defeats the purpose

32. 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

33. Apgar Scores and CP

34. Percent CP vs Late Apgar Score

35. 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

36. 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

37. 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

38. 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

39. CXRay

40. 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

41. CXRay

42. 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