Symposium Papers - Respiratory Care

1 Symposium PapersOxygen Therapy in the Neonatal Care EnvironmentBrian K Walsh RRT-NPS, Toni M Brooks RRT, and Barry M Grenier RRT-NPSI ntroductionPhysiologic Effects of Oxygen Therapy: Benefits and Adverse EffectsTreatment of HypoxiaOxidative StressRetinopathy of PrematurityChronic Lung DiseaseLong-Term OutcomesOxygen During ResuscitationOxygen Delivery DevicesBlow-By OxygenOxygen HoodLow-Flow Nasal CannulaHigh-Flow Nasal CannulaDevice-Related ComplicationsAdvances in Oxygen TherapyClosed-Loop FIO2 RegulationNew-Generation Pulse OximetryDiscussionUnresolved QuestionsFuture of Neonatal Oxygen TherapyThe use of oxygen in the treatment of neonates with Respiratory distress has been reported for morethan a century.

2 Oxygen therapy is generally titrated to one or more measures of blood oxygenationand administered to reverse or prevent hypoxia. Individual responses to oxygen therapy varygreatly, depending on the particular cause of hypoxia and the degree of impairment. Despite thisfocused purpose, oxygen administration in this patient population has become complex. The longerwe deliver this drug, the more we discover its beneficial and detrimental effects. New and innovativeways to deliver and monitor this therapy have improved outcomes. Despite this vast experiencethere still remain some unanswered questions regarding the use of oxygen in the neonatal envi-ronment.

3 Nonetheless, oxygen is a major staple in our treatment arsenal for words:oxygen; neonatal; infant, newborn; retinopathy of prematurity; oxygen inhalation therapy.[Respir Care2009;54(9):1193 1202. 2009 Daedalus Enterprises]IntroductionThe use of oxygen in the treatment of neonates withrespiratory distress has been reported for more than a cen-tury. In 1907, Budin recommended oxygen suppliedthrough a funnel, the large opening of which is placedbeside the infant s face, for the treatment of cyanoticepisodes in the 1930s, Hess2,3developed anincubator (Fig.)

4 1) capable of delivering approximately 40%oxygen for extended periods of time. By the 1940s, aBrian K Walsh RRT-NPS, Toni M Brooks RRT, and Barry M GrenierRRT-NPS are affiliated with the Respiratory Care Department, Chil-dren s Hospital Boston, Boston, authors have disclosed no conflicts of Walsh presented a version of this manuscript at the New HorizonsSymposium, Neonatal Respiratory Care, at the International Respira-tory Congress of the American Association for Respiratory Care, at the54th International Respiratory Congress of the American Association forRespiratory Care, held December 13-16, 2008, in Anaheim.

5 SEPTEMBER2009 VOL54 NO91193commercially available incubator capable of providing ahigh concentration of oxygen facilitated the liberal use ofoxygen for the treatment of cyanosis, apnea, and periodicbreathing in ,4 Throughout this time, oxygenadministration was guided by the clinical observations ofskin color, as well as the rate, regularity, and work ofbreathing. It wasn t until the 1960s and 1970s that tech-nology micro-sampling of blood gases, transcutaneousoxygen monitoring, and, later, pulse oximetry becameavailable for more precise monitoring of physiologic overall goal of oxygen therapy is to achieve ade-quate oxygenation using the lowest concentration of in-spired oxygen.

6 However, achieving this goal is compli-cated by a number of factors. Despite over 75 years ofroutine oxygen administration to newborn infants, the op-timal level of oxygenation one that avoids the detrimen-tal effects of hypoxia on the one hand, and those caused byhyperoxia on the other has not yet been clearly defined,5-7leading to wide variations in the term ad-equate oxygenation is not complicating fac-tors in achieving the goals of neonatal oxygen therapyinclude patient size, tolerance of delivery devices, andvariability in the use of delivery devices.

7 Which suggestthat clinicians often lack adequate knowledge in the use ofoxygen delivery equipment,10and the lack of training inthe concepts of neonatal oxygenation and equipment usedto monitor the effects of oxygen Effects of Oxygen Therapy:Benefits and Adverse EffectsDespite its universal acceptance as a life-saving therapyfor newborns, oxygen administration is associated withnumerous physiologic effects, particularly when used totreat premature of HypoxiaWhile oxygen therapy is generally titrated to some mea-sure of arterial oxygenation in response to an abnormallyCorrespondence: Brian K Walsh RRT-NPS, Respiratory Care Depart-ment, Children s Hospital Boston, 300 Longwood Avenue, MA-861,Boston MA 02115.

8 E-mail: 1. Hess bed equipped with an oxygen therapy unit (A-side view). 1: Pressure gauge. 2: Oxygen flow regulator. 3: Flow meter. 4: Glassand metal hinged door for feeding purposes. 5: Thermometer window. 6: Metal hinged door for purposes of body care of the : Ventilator with small and large exit openings. 8 12:Controls for maintaining temperature in water-jacket of the incubator. (From Refer-ence 3, with permission.)OXYGENTHERAPY IN THENEONATALCAREENVIRONMENT1194 RESPIRATORYCARE SEPTEMBER2009 VOL54 NO9low level of blood oxygen, orhypoxemia, oxygen is ad-ministered to the neonate to reverse or prevent is defined as a deficit of oxygen at the cellularlevel, and is commonly caused by one or more of thefollowing: the reduced availability of oxygen at the alve-olar level, due to pulmonary disease (hypoventilation, un-even matching of ventilation to perfusion, diffusion de-fects); intrapulmonary shunts or right to left cardiacshunts.

9 Reduced oxygen carrying capacity due to anemia orabnormal blood hemoglobin; or impaired oxygen deliverydue to shock, heart failure, or localized decreases in ,13 Left untreated, hypoxia can lead to serious andpermanent brain injury and responses to oxygen therapy vary greatly,depending on the particular cause of hypoxia and the de-gree of impairment. Hypoxia caused by hypoventilationand ventilation-perfusion anomalies associated with pul-monary disease will be most responsive to oxygen large increases in FIO2will produce only small in-creases in available oxygen if hypoxia is caused by cardiacshunts, shock, and hemoglobin ,13It should be stressed, however, that even small increases inoxygen availability may prevent life-threatening decom-pensation in the hypoxic StressThe role of oxygen and oxidative stress in the develop-ment of a number of neonatal diseases has generated muchinterest.

10 Oxidative stress has been defined as an imbalancebetween pro-oxidant and anti-oxidant forces in the include oxygen radicals or reactive oxygenspecies, which can be cytotoxic because of their ability toalter cellular components and function. Reactive oxygenspecies are generated as a result of normal mitochondrialrespiration, but also during the reperfusion phase of hy-poxic tissue injury and in association with infection ,16 Oxygen is toxic because of the pro-duction of reactive oxygen species; thus oxygen adminis-tration increases oxidative defenses include the enzymes superoxidedismutase, catalase, and glutathione.