Correction: Expired CO2 Levels Indicate Degree of Lung Aeration at Birth

Carbon dioxide monitoring during neonatal stabilisation at delivery (COSTA-Neo)-Multi centre observational study

BACKGROUND

The data is evolving on exhaled carbon dioxide (ECO2) levels for preterm infants requiring stabilisation.

OBJECTIVES

To establish the trends of ECO2 levels during the first 10 minutes of stabilisation in preterm infants at birth.

METHODS

We conducted a multi-centre, prospective observational study. We included all preterm infants ≤ 32 weeks needing stabilisation. We recorded blinded ECO2 using Masimo Rad-97TM Pulse oximeter with Capnography. We used the first 10 minutes of ECO2, pulse rate (PR) and oxygen saturation (SpO2) data from pulse oximeter for our analysis. We collected stabilisation and clinical details. Ethics approval and informed consent was obtained.

RESULTS

We recruited 150 preterm infants, with data of 131 babies available for analysis. Median (and interquartile range) birth gestational age and birth weight were 28 (26.5 - 30) weeks and 1110 (800- 1422.5) grams. All infants received positive end expiratory pressure (PEEP). In addition, 91 (69%) received positive pressure inflations, 34 (26%) received only PEEP and 34 (26%) were intubated within the first 10 minutes of life. Using bootstrapping, the 50% confidence interval for ECO2 at 5 minutes was estimated to range from 3.042 kPa1 to 3.328 kPa and has minimal change after 5 minutes. ECO2 appeared earlier than any valid PR and SpO2 data with median time difference of 16 (2-22) s) and 14 (0-20) s respectively.

CONCLUSIONS

We have provided trends of ECO2 in preterm infants needing stabilisation during the first 10 minutes of life. ECO2 appeared at least as early as any valid PR and earlier than SpO2.

Expired carbon dioxide during newborn resuscitation as predictor of outcome

AIM

To explore and compare expired CO₂ (ECO₂) and heart rate (HR), during newborn resuscitation with bag-mask ventilation, as predictors of 24-h outcome.

METHODS

Observational study from March 2013 to June 2017 in a rural Tanzanian hospital. Side-stream measures of ECO₂, ventilation parameters, HR, clinical information, and 24-h outcome were recorded in live born bag-mask ventilated newborns with initial HR < 120 bpm. We analysed the data using logistic regression models and compared areas under the receiver operating curves (AUC) for ECO₂ and HR within three selected time intervals after onset of ventilation (0-30 s, 30.1-60 s and 60.1-300 s).

RESULTS

Among 434 included newborns (median birth weight 3100 g), 378 were alive at 24 h, 56 had died. Both ECO₂ and HR were independently significant predictors of 24-h outcome, with no differences in AUCs. In the first 60 s of ventilation, ECO₂ added extra predictive information compared to HR alone. After 60 s, ECO₂ lost significance when adjusted for HR. In 70% of newborns with initial ECO₂ <2% and HR < 100 bpm, ECO₂ reached ≥2% before HR ≥ 100 bpm. Survival at 24 h was reduced by 17% per minute before ECO₂ reached ≥2% and 44% per minute before HR reached ≥100 bpm.

CONCLUSIONS

Higher levels and a faster rise in ECO₂ and HR during newborn resuscitation were independently associated with improved survival compared to persisting low values. ECO₂ increased before HR and may serve as an earlier predictor of survival.

Establishment of functional residual capacity at birth: Observational study of 821 neonatal resuscitations

AIM OF THE STUDY

Establishing functional residual capacity (FRC) during positive pressure ventilation (PPV) of apnoeic neonates is critical for survival. This may be difficult due to liquid-filled airways contributing to low lung compliance. The objectives were to describe initial PPV, changes in lung compliance and establishment of FRC in near-term/term neonates ≥36 weeks gestation at birth.

METHODS

Observational study of all neonatal resuscitations between 01.07.13 and 30.06.18 in a Tanzanian referral hospital. Perinatal events and characteristics were observed and recorded by trained research assistants. PPV were performed using self-inflating bag-masks without positive end-expiratory pressure (PEEP). Ventilation signals (pressure/flow), expired CO₂ (ECO₂) and heart rate were recorded by resuscitation monitors.

RESULTS

19,587 neonates were born, 1451 received PPV, of these 821 of median (p25, p75) birthweight 3180 (2844, 3500) grams and gestation 38 (37, 40) weeks had ≥20 ventilations and complete datasets. There was a significant increase in expired volume (from 3.3 to 6.0 ml/kg), ECO₂ (0.3-2.4%), lung compliance (0.13-0.19 ml/kg/mbar) and heart rate (109-138 beats/min) over the first 20 PPVs. Inflation volume, time, and peak inflation pressure (PIP) were stable around 12-13 ml/kg, 0.45 s, and 36 mbar, respectively.

CONCLUSIONS

The combination of increasing expired volumes, ECO₂, and heart rate with decreasing inflation/expired volume ratios and constant PIP, suggests establishment of FRC during the first 20 PPVs in near-term/term neonates using a self-inflating bag-mask without PEEP, the most common device worldwide for ventilating non-breathing neonates. Initial lung compliance is low, and with short inflation times, higher than recommended PIP seem necessary to deliver adequate tidal volumes.

Predictors for expired CO2 in neonatal bag-mask ventilation at birth: observational study

BACKGROUND

Expired carbon dioxide (ECO2) indicates degree of lung aeration immediately after birth. Favourable ventilation techniques may be associated with higher ECO2 and a faster increase. Clinical condition will however also affect measured values. The aim of this study was to explore the relative impact of ventilation factors and clinical factors on ECO2 during bag-mask ventilation of near-term newborns.

METHODS

Observational study performed in a Tanzanian rural hospital. Side-stream measures of ECO2, ventilation data, heart rate and clinical information were recorded in 434 bag-mask ventilated newborns with initial heart rate <120 beats per minute. We studied ECO2 by clinical factors (birth weight, Apgar scores and initial heart rate) and ventilation factors (expired tidal volume, ventilation frequency, mask leak and inflation pressure) in random intercept models and Cox regression for time to ECO2 >2%.

RESULTS

ECO2 rose non-linearly with increasing expired tidal volume up to >10 mL/kg, and sufficient tidal volume was critical for the time to reach ECO2 >2%. Ventilation frequency around 30/min was associated with the highest ECO2. Higher birth weight, Apgar scores and initial heart rate were weak, but significant predictors for higher ECO2. Ventilation factors explained 31% of the variation in ECO2 compared with 11% for clinical factors.

CONCLUSIONS

Our findings indicate that higher tidal volumes than currently recommended and a low ventilation frequency around 30/min are associated with improved lung aeration during newborn resuscitation. Low ECO2 may be used to identify unfavourable ventilation technique. Clinical factors are also associated with persistently low ECO2 and must be accounted for in the interpretation.

Systematic Review of Capnography with Mask Ventilation during Cardiopulmonary Resuscitation Maneuvers

The latest guidelines identify capnography as an instrument used to assess bag-valve-mask ventilation during cardiopulmonary resuscitation (CPR). In this review, we analyzed the feasibility and reliability of capnography use with face mask ventilation during CPR maneuvers in adults and children. This systematic review was completed in December 2018; data for the study were obtained from the following databases: EBSCOhost, SCOPUS, PubMed, Índice Bibliográfico Español en Ciencias de la Salud (IBECS), TESEO, and Cochrane Library Plus. Two reviewers independently assessed the eligibility of the articles; we analyzed publications from different sources and identified studies that focused on the use of capnography with a face mask during CPR maneuvers in order to describe the capnometry value and its correlation with resuscitation outcomes and the assistance of professionals. A total of 888 papers were collected, and 17 papers were included that provided objective values for the use of capnography with a mask for ventilation. Four were randomized clinical trials (RCT) and the rest were observational studies. Four studies were completed in adults and 13 were completed in newborns. After the analysis of the papers, we recommended a capnographic level of C in adults and B in newborns. Despite the little evidence obtained, capnography has been demonstrated to facilitate the advanced clinical practice of mask ventilation in cardiopulmonary resuscitation, to be reliable in the early detection of heart rate increase in newborns, and to asses in-airway patency and lung aeration during newborn resuscitation.

Systematic Review of Capnography with Mask Ventilation during Cardiopulmonary Resuscitation Maneuvers

The latest guidelines identify capnography as an instrument used to assess bag-valve-mask ventilation during cardiopulmonary resuscitation (CPR). In this review, we analyzed the feasibility and reliability of capnography use with face mask ventilation during CPR maneuvers in adults and children. This systematic review was completed in December 2018; data for the study were obtained from the following databases: EBSCOhost, SCOPUS, PubMed, Índice Bibliográfico Español en Ciencias de la Salud (IBECS), TESEO, and Cochrane Library Plus. Two reviewers independently assessed the eligibility of the articles; we analyzed publications from different sources and identified studies that focused on the use of capnography with a face mask during CPR maneuvers in order to describe the capnometry value and its correlation with resuscitation outcomes and the assistance of professionals. A total of 888 papers were collected, and 17 papers were included that provided objective values for the use of capnography with a mask for ventilation. Four were randomized clinical trials (RCT) and the rest were observational studies. Four studies were completed in adults and 13 were completed in newborns. After the analysis of the papers, we recommended a capnographic level of C in adults and B in newborns. Despite the little evidence obtained, capnography has been demonstrated to facilitate the advanced clinical practice of mask ventilation in cardiopulmonary resuscitation, to be reliable in the early detection of heart rate increase in newborns, and to asses in-airway patency and lung aeration during newborn resuscitation.

Effective ventilation: The most critical intervention for successful delivery room resuscitation

Lung aeration is the critical first step that triggers the transition from fetal to postnatal cardiopulmonary physiology after birth. When an infant is apneic or does not breathe sufficiently, intervention is needed to support this transition. Effective ventilation is therefore the cornerstone of neonatal resuscitation. In this article, we review the physiology of cardiopulmonary transition at birth, with particular attention to factors the caregiver should consider when providing ventilation. We then summarize the available clinical evidence for strategies to monitor and perform positive pressure ventilation in the delivery room setting.

Using exhaled CO2 to guide initial respiratory support at birth: a randomised controlled trial

IMPORTANCE

A sustained inflation (SI) provided at birth might reduce bronchopulmonary dysplasia (BPD).

OBJECTIVE

This study aims to examine whether an SI-guided exhaled carbon dioxide (ECO₂) compared with positive pressure ventilation (PPV) alone at birth decreases BPD.

DESIGN

Randomised controlled trial. Infants were randomly allocated to either SI (SI group) or PPV (PPV group).

PARTICIPANTS

Participants of this study include infants between 23⁺⁰ and 32⁺⁶ weeks gestation with a need for PPV at birth.

INTERVENTION

Infants randomised into the SI group received an initial SI with a peak inflation pressure (PIP) of 24 cmH₂O over 20 s. The second SI was guided by the amount of ECO₂. If ECO₂ was ≤20 mm Hg, a further SI of 20 s was delivered. If ECO₂ was >20 mm Hg the second SI was 10 s. Infants randomised into the PPV group received mask PPV with an initial PIP of 24 cmH₂O.

PRIMARY OUTCOMES

Reduction in BPD defined as the need for respiratory support or supplemental oxygen at corrected gestational age of 36 weeks.

RESULTS

SI (n=76) and PPV (n=86) group had similar rates of BPD (23% vs 33%, p=0.090, not statistically significant). The duration of mechanical ventilation was significantly reduced with SI versus PPV (63 (10-246) hours versus 204 (17-562) hours, respectively (p=0.045)). No short-term harmful effects were identified from two SI lasting up to 40 s (eg, pneumothorax, intraventricular haemorrhage or patent ductus arteriosus).

CONCLUSION

Preterm infants <33 weeks gestation receiving SI at birth had lower duration of mechanical ventilation and similar incidence of BPD compared with PPV. Using ECO₂ to guide length of SI is feasible.

TRIAL REGISTRATION NUMBER

NCT01739114; Results.