Integration of a respiratory function monitor into newborn positive pressure ventilation training; development of a standardised training intervention

Objective

One in twenty newborns require resuscitation with positive pressure ventilation (PPV) at birth. Newborn face mask ventilation is often poorly performed. To address this, the potential role of respiratory function monitors (RFM) in newborn resuscitation training has been highlighted. The objective of this study was to develop a standardised training intervention on newborn PPV using an RFM with a simple visual display to identify and correct suboptimal ventilations.

Methods

We adapted the framework from a simulation development guideline to create a hands-on intervention on newborn PPV using an RFM with simple visual feedback (Monivent NeoTraining). We enrolled a group of healthcare professionals to a manikin-based pilot study as part of this process, conducting a series of teaching sessions to refine the intervention. Suggested changes were gathered from participants and instructors. Our main objective was to develop a standardised, reproducible training intervention.

Results

A standardised training intervention on newborn PPV was systematically developed. Twenty-six healthcare professionals working in tertiary neonatal care participated in a pilot study, consisting of eight training sessions. Each iteration of the intervention was informed by the previous session. Instructions for the delivery of teaching were standardised and a training algorithm was developed.

Conclusion

RFM's have been shown to be effective tools in research settings, addressing poor technique and face mask leak. They are not routinely used in newborn resuscitation training. To address this, we developed a standardised training intervention on newborn PPV using an RFM with simple visual feedback.

A dose response study of inhaled nitric oxide in hypoxic respiratory failure in preterm infants

BACKGROUND

Inhaled nitric oxide (iNO) is used widely in newborn infants with hypoxic respiratory failure, despite the known and theoretical toxicity of iNO, and a relative lack of information about appropriate doses.

AIM

To determine whether a dose-response relationship existed for iNO in preterm infants.

DESIGN

A four-period, four-dose, cross-over design was used with iNO given for 15 min in a randomised sequence in concentrations of 5, 10, 20 and 40 parts per million (ppm), with a minimum 5 min wash-out period. Data on ventilatory, blood gas and other physiological measurements were recorded before and at the end of each period. The relationship of clinical response with iNO dose and period was analysed using multivariate regression.

SUBJECTS

Infants with gestational age < 34 weeks and < 28 days postnatal age with hypoxic respiratory failure were recruited.

OUTCOME MEASURE

A clinically significant dose-response was defined as a rise in the post-ductal arterial oxygen tension (PaO(2)) of at least 3 kPa.

RESULTS

Thirteen infants were recruited. At trial entry, ten were < 3 days of age; 11 were being treated with high frequency oscillatory ventilation; median (inter-quartile range) gestational age 27 (25-29) weeks; birthweight 983 (765-1120) g; oxygenation index 27.1 (21.8-28.8). Six infants (46%) showed a clinically significant response. After adjusting for period and patient effect, no evidence for an overall dose effect was identified (likelihood ratio test, p=0.34).

CONCLUSION

No evidence of a dose-response relationship with iNO was found in this study of very preterm infants with respiratory failure.

The role of matrix metalloproteinases -9 and -2 in development of neonatal chronic lung disease

AIM

Matrix metalloproteinases (MMPs) -9 and -2 degrade type-IV collagen, a major constituent of lung basement membrane, and may have a role in the pathogenesis of neonatal chronic lung disease (CLD). We determined factors influencing MMP levels in neonatal bronchoalveolar lavage (BAL) fluid to establish whether an imbalance between MMP and its inhibitor could be implicated in CLD.

METHODS

We measured MMP-9 and -2 and tissue inhibitor of metalloproteinase-1 (TIMP-1) levels in 316 BAL fluid samples from 121 babies of gestational ages 23 to 42 wk over the first 14 d of life to determine effects of gestation and postnatal age. Median MMP-9, -2, TIMP-1 and MMP-9/TIMP-1 ratio in BAL were further studied in a subgroup of 85 babies <33 wk gestation to determine their ability to predict CLD and to establish effects of antenatal corticosteroid therapy (ANCS).

RESULTS

MMP-9, -2 and TIMP levels did not vary with postnatal age over the first week. Median MMP-9 levels and MMP-9/TIMP-1 ratio increased with decreasing gestation in preterm babies. The MMP-9/TIMP-1 ratio was higher in babies who developed CLD, implying a proteinase/antiproteinase imbalance, but this association disappeared when controlled for gestational age. ANCS had no effect on BAL fluid MMP or TIMP levels.

CONCLUSION

MMPs may have a role in the development of lung injury and fibrosis, but estimating their levels in the first week of life does not help with prediction of CLD.

Chorioamnionitis increases matrix metalloproteinase-8 concentrations in bronchoalveolar lavage fluid from preterm babies

OBJECTIVE

To determine the effects of chorioamnionitis and antenatal corticosteroids on matrix metalloproteinase-8 (MMP-8) concentrations in bronchoalveolar lavage (BAL) fluid from preterm babies in the first week of life.

DESIGN

Prospective observational study.

SETTING

Regional neonatal intensive care unit.

PATIENTS

Thirty five ventilated preterm babies < 33 weeks gestation, seven of whom were born after chorioamnionitis, which was diagnosed histologically as the presence of inflammatory cells in the chorioamnionic plate.

METHODS

MMP-8 was measured by enzyme linked immunosorbent assay (ELISA) in 90 serial BAL samples taken during the first six postnatal days. The median MMP-8 concentration for each baby was calculated.

RESULTS

Median MMP-8 concentrations were higher in the chorioamnionitis group than in those without (43 v 5 ng/ml). Partial or complete courses of antenatal corticosteroids had no effect on MMP-8 concentrations.

CONCLUSIONS

Higher concentrations of MMP-8 are found in BAL fluid from preterm babies from pregnancies complicated by chorioamnionitis. This type I collagenase may contribute to the lung injury that occurs in some babies with respiratory distress syndrome.

Type I collagenases in bronchoalveolar lavage fluid from preterm babies at risk of developing chronic lung disease

OBJECTIVE

To assess whether increased collagenolysis precedes severe chronic lung disease (CLD).

METHODS

Matrix metalloproteinase-1 (MMP-1) and MMP-8 (enzymes that degrade type I collagen, the main structural protein of lung extracellular matrix) were measured by enzyme linked immunosorbent assay in 100 bronchoalveolar lavage samples taken during the first 6 postnatal days from 45 ventilated preterm babies < 33 weeks gestation. The median value for each baby was calculated. CLD was defined as an oxygen requirement after the 36th week after conception.

RESULTS

MMP-8 levels in bronchoalveolar lavage fluid were higher (median 13 ng/ml) in 20 babies who developed CLD than in 25 without CLD (median 2 ng/ml). No MMP-1 was detected in any sample.

CONCLUSIONS

MMP-8 can be detected in bronchoalveolar lavage fluid from preterm babies, and higher levels are found in those who later develop CLD. MMP-8 may contribute to lung injury that occurs as a prelude to CLD.

The present status of exogenous surfactant for the newborn

This year is the 20th anniversary of the first successful trial of exogenous surfactant for respiratory distress syndrome in the newborn and it is perhaps a good time to review recent advances in basic science and clinical practice as they relate to surfactant therapy.

[Treatment of very low birth weight infant: is it evidenced-based?]

AIM

To determine what percentage of therapeutic interventions for very low birth weight infants undergoing neonatal intensive care is evidence based.

METHODS

The management of 80 very low birth weight infants admitted to our neonatal unit during 1998 was retrospectively reviewed. For each clinical diagnosis e.g. respiratory distress syndrome, patent ductus arteriosus or chronic lung disease all interventions were recorder. Each intervention was then categorised according to the level of supporting evidence. Level I was supported by evidence from randomised controlled trials or meta-analysis of multiple trials. Level II included interventions backed by convincing non-experimental evidence where randomised controlled trials would be unnecessary or unethical. Level III were treatments in common use without substantial supporting evidence. These categorizations were made after extensive researching of Medline, The Cochrane Database and the Randomised Controlled Trial Register, detailed hand-searching of the literature as well as using local expertise and knowledge.

RESULTS

943 separate interventions were recorded in the charts of the 80 babies. Overall 91.3% were shown to be evidence-based of which 58.7% were level I, 32.6% were level II and only 8.7% were level III.

CONCLUSIONS

91.3% of interventions for very low birth weight infants in our neonatal intensive care unit were evidence-based and only 8.7% had no substantial supporting evidence. Care of the very low birthweight infants is largely evidence-based.