title: Impact of Changing Clinical Practices on Early Blood Gas Analyses in Very Preterm Infants and Their Associated Inpatient Outcomes.
abstract: BACKGROUND
  Early studies suggest an association of abnormal carbon dioxide (PCO2) or oxygen (PO2) levels with adverse inpatient outcomes in very preterm babies. Recent resuscitation practice changes, such as targeted oxygen therapy, end-expiratory pressure, and rescue surfactant may influence these associations.
  
  
  OBJECTIVE
  The aim of this study is to assess the range of the initial partial pressures of PCO2and PO2in preterm neonates <33 weeks gestational age after birth and their correlation to inpatient neonatal outcomes.
  
  
  METHODS
  This is a prospective observational cohort study of infants <33 weeks gestational age with arterial or venous blood gas analysis performed within the first hour after birth.
  
  
  RESULTS
  One hundred seventy infants (arterialn= 75, venousn= 95) with mean (SD) gestational age of 28 (3) weeks and birth weight of 1,111 (403) g were included. None of the infants with arterial blood gases had hypocarbia (<30 mmHg), 32 (43%) had normocarbia (30-55 mmHg), and 43 (57%) had hypercarbia (>55 mmHg). Seventeen of the infants with arterial blood gases (22%) had hypoxia (<50 mmHg), 50 (67%) normoxia, and 8 (11%) hyperoxia (>80 mmHg). In infants with venous blood samples, none had venous PCO2< 40 mmHg, 41 (43%) had venous PCO240-60 mmHg, and 54 (57%) had venous PCO2> 60 mmHg. Multivariable logistic regression analysis showed no association of low or high PCO2or PO2with death or major inpatient morbidities.
  
  
  CONCLUSIONS
  With current resuscitation and stabilization practices, hyperoxia and hypocarbia was uncommon, and hypercarbia occurred frequently. None of these findings correlate with adverse inpatient outcomes or death. Our findings are in direct contrast to published observations using historical practices.
authors.affiliation: Centre for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, AB, Canada; Department of Pediatrics, Hong Kong University-Shenzhen Hospital, Shenzhen, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Huang
authors.affiliation: Centre for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, AB, Canada; Department of Pediatrics, Hong Kong University-Shenzhen Hospital, Shenzhen, China; Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.
authors.forename: Po-Yin
authors.initials: PY
authors.lastname: Cheung
authors.affiliation: Centre for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, AB, Canada; Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.
authors.forename: Megan
authors.initials: M
authors.lastname: O'Reilly
authors.affiliation: Centre for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital , Edmonton, AB , Canada.
authors.forename: Sylvia
authors.initials: S
authors.lastname: van Os
authors.affiliation: Centre for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital , Edmonton, AB , Canada.
authors.forename: Anne Lee
authors.initials: AL
authors.lastname: Solevåg
authors.affiliation: Centre for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, AB, Canada; Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.
authors.forename: Khalid
authors.initials: K
authors.lastname: Aziz
authors.affiliation: Centre for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, AB, Canada; Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.
authors.forename: Georg M
authors.initials: GM
authors.lastname: Schmölzer
keywords: blood gas; delivery room; hypercarbia; hyperoxia; hypocarbia; hypoxia; infants; neonatal resuscitation