Morag Campbell

End tidal carbon dioxide levels during the resuscitation of prematurely born infants.

BACKGROUND Successful resuscitation of prematurely born infants is dependent on achieving adequate alveolar ventilation and vasodilation of the pulmonary vascular bed. Elevation of end-tidal carbon dioxide (ETCO(2)) levels may indicate pulmonary vasodilation. AIMS This research aims to study the temporal changes in ETCO(2) levels and the infants respiratory efforts during face mask resuscitation in the labour suite, and to determine if the infants first inspiratory effort was associated with a rise in the ETCO(2) levels, suggesting pulmonary vasodilation had occurred. STUDY DESIGN This study is an observational one. SUBJECTS The subjects of the study are forty infants with a median gestational age of 30 weeks (range 23-34). OUTCOME MEASURES Inflation pressures, expiratory tidal volumes and ETCO(2) levels were measured. RESULTS The median expiratory tidal volume of inflations prior to the onset of the infants respiratory efforts (passive inflations) was lower than that of the inflation associated with the first inspiratory effort (active inflation) (1.8 (range 0.1-7.3) versus 6.3 ml/kg (range 1.9-18.4), p<0.001), as were the median ETCO(2) levels (0.3 (range 0.1-2.1) versus 3.4 kPa (0.4-11.5), p<0.001). The median expiratory tidal volume (4.5 ml/kg (range 0.5-18.3)) and ETCO(2) level (2.2 kPa (range 0.3-9.3)) of the two passive inflations following the first active inflation were also higher than the median expiratory tidal volume and ETCO(2) levels of the previous passive inflations (p<0.001, p<0.0001 respectively). CONCLUSION These results suggest that during face mask resuscitation, improved carbon dioxide elimination, likely due to pulmonary vasodilation, occurred with the onset of the infants respiratory efforts.

Survey of UK newborn resuscitation practices.

Surveys of newborn resuscitation practices1,–,4 have revealed differences between and in countries, but the equipment and techniques used in the UK are guided by the UK Resuscitation Council, and staff involved must undertake a newborn life support course. We hypothesised, therefore, that in the UK there would be consistency of practice regardless of the level of neonatal care, and our aim was to test this hypothesis. A questionnaire was sent to the lead paediatrician of 212 hospitals with newborn units. Differences in resuscitation practices according to the level of neonatal care were assessed for statistical significance using the χ2 test. There was an 85% response. …

The first five inflations during resuscitation of prematurely born infants

Objective To study the first five inflations during the resuscitation of prematurely born infants and whether the infants inspiratory efforts influenced the expired tidal volume. Design Prospective observational study. Setting Two tertiary perinatal centres. Patients Thirty infants, median gestational age 30 (23–34) weeks. Interventions The first five inflations delivered via a face mask and t-piece device were examined using respiratory function monitoring. Main outcome measures Inflation pressures, inflation times and expiratory volumes were recorded and comparison made of inflations during which the infant made an inspiratory effort (active inflation) or did not (passive inflation). Results Overall, the median expired tidal volume was 2.5 (0–19.8) ml/kg and was lower for passive (median 2.1 ml/kg, range 0–19.8 ml/kg) compared with active (median 5.6 ml/kg, range 1.2–12.2 ml/kg) inflations (ratio of geometric means 1.85, 95% CI 1.18 to 28%) (p=0.007). Overall, the median face mask leak was 54.5% and was lower for active (34.5%) compared with passive (60.7%) inflations (mean difference in % leak: 12.4%, 95% CI 0.9 to 24%) (p=0.0354). There was a significant positive correlation between the expiratory volumes and the inflation pressures (R2 between subjects 0.19, p=0.04) and a negative correlation between the expiratory tidal volumes and the face mask leaks (R2 between subjects=0.051, p<0.001), but there was no significant correlation between the inflation times and the expiratory tidal volumes. Conclusion The expired tidal volume, inflation pressures and times during the first five inflations during resuscitation were variable. The expired tidal volumes were significantly greater if the infant inspired during the inflation.

Neuromuscular Blockade and Lung Function during Resuscitation of Infants with Congenital Diaphragmatic Hernia

Background: There is no consensus or evidence as to whether a neuromuscular blocking agent should be used during the initial resuscitation of infants with congenital diaphragmatic hernia (CDH) in the labour ward. Objective: To determine if administration of a neuromuscular blocking agent affected the lung function of infants with CDH during their initial resuscitation in the labour ward. Methods: Fifteen infants with CDH were studied (median gestational age 38 weeks, range 34–41; birth weight 2,790 g, range 1,780–3,976). Six infants had undergone feto-endotracheal occlusion (FETO). Flow, airway pressure, tidal volume and dynamic lung compliance changes were recorded using a respiratory function monitor (NM3, Respironics). Twenty inflations immediately before, immediately after and 5 min after administration of a neuromuscular blocking agent (pancuronium bromide) were analysed. Results: The median dynamic lung compliance of the 15 infants was 0.22 ml/cm H2O/kg (range 0.1–0.4) before and 0.16 ml/cm H2O/kg (range 0.1–0.3) immediately after pancuronium bromide administration (p < 0.001) and remained at a similar low level 5 min after pancuronium bromide administration. The FETO compared to the non-FETO infants had a lower median dynamic compliance both before (p < 0.0001) and 5 min after pancuronium administration (p < 0.001) and required significantly longer durations of ventilation (p = 0.004), supplementary oxygen (p = 0.003) and hospitalisation (p = 0.007). Conclusions: Infants with CDH, particularly those who have undergone FETO, have a low lung compliance at birth, and this is further reduced by administration of a neuromuscular blocking agent.

Detection of exhaled carbon dioxide following intubation during resuscitation at delivery

Objectives End tidal carbon dioxide (ETCO2) monitoring can facilitate identification of successful intubation. The aims of this study were to determine the time to detect ETCO2 following intubation during resuscitation of infants born prematurely and whether it differed according to maturity at birth or the Apgar scores (as a measure of the infant’s condition after birth). Design Analysis of recordings of respiratory function monitoring. Setting Two tertiary perinatal centres. Patients Sixty-four infants, with median gestational age of 27 (range 23–34)weeks. Interventions Respiratory function monitoring during resuscitation in the delivery suite. Main outcome measures The time following intubation for ETCO2 levels to be initially detected and to reach 4 mm Hg and 15 mm Hg. Results The median time for initial detection of ETCO2 following intubation was 3.7 (range 0–44) s, which was significantly shorter than the median time for ETCO2 to reach 4 mm Hg (5.3 (range 0–727) s) and to reach 15 mm Hg (8.1 (range 0–827) s) (both P<0.001). There were significant correlations between the time for ETCO2 to reach 4 mm Hg (r=−0.44, P>0.001) and 15 mm Hg (r=−0.48, P<0.001) and gestational age but not with the Apgar scores. Conclusions The time for ETCO2 to be detected following intubation in the delivery suite is variable emphasising the importance of using clinical indicators to assess correct endotracheal tube position in addition to ETCO2 monitoring. Capnography is likely to detect ETCO2 faster than colorimetric devices.