Respiratory function after birth in infants with congenital diaphragmatic hernia

OBJECTIVE

To characterise the transitional pulmonary physiology of infants with congenital diaphragmatic hernia (CDH) using measures of expiratory tidal volume (TV) and end-tidal carbon dioxide (ETCO2).

DESIGN

Prospective single-centre observational study.

SETTING

Quaternary neonatal intensive care unit.

PATIENTS

Infants with an antenatal diagnosis of CDH born at the Children's Hospital of Philadelphia.

INTERVENTIONS

TV and ETCO2 were simultaneously recorded using a respiratory function monitor (RFM) during invasive positive pressure ventilation immediately after birth.

MAIN OUTCOME MEASURES

TV per birth weight and ETCO2 values were summarised for each minute after birth. Subgroups of interest were defined by liver position (thoracic vs abdominal) and extracorporeal membrane oxygenation (ECMO) treatment.

RESULTS

RFM data were available for 50 infants from intubation until a median (IQR) of 9 (7-14) min after birth. TV and ETCO2 values increased for the first 10 min after birth, but intersubject values were heterogeneous. TVs were overall lower and ETCO2 values higher in infants with an intrathoracic liver and infants who were ultimately treated with ECMO. On hospital discharge, survival was 88% (n=43) and 34% (n=17) of infants were treated with ECMO.

CONCLUSION

Respiratory function immediately after birth is heterogeneous for infants with CDH. Lung aeration, as evidenced by expired TV and ETCO2, appears to be ongoing throughout the first 10 min after birth during invasive positive pressure ventilation. Close attention to expired TV and ETCO2 levels by 10 min after birth may provide an opportunity to optimise and individualise ventilatory support for this high-risk population.

Common Quality Improvement Methodologies Including the Model for Improvement, Lean, and Six Sigma

This article reviews several common quality improvement methodologies, including the Model for Improvement, Lean, and Six Sigma. We demonstrate how these methods are based on a similar improvement science foundation. We describe the tools used to understand problems in the context of systems and the mechanisms to learn and build knowledge, using specific examples from the neonatology and pediatric literature. We conclude with a discussion on the importance of the human side of change in quality improvement, including team formation and culture.

Use of ventilation/perfusion mismatch to guide individualised CPAP level selection in preterm infants: a feasibility trial

OBJECTIVE

To measure within-subject changes in ventilation/perfusion (V'/Q') mismatch in response to a protocol of individualised nasal continuous positive airway pressure (CPAP) level selection.

DESIGN

Single-arm, non-randomised, feasibility trial.

SETTING

Three centres in the Children's Hospital of Philadelphia neonatal care network.

PATIENTS

Twelve preterm infants of postmenstrual age 27-35 weeks, postnatal age >24 hours, and receiving a fraction of inspired oxygen (FiO₂) >0.25 on CPAP of 4-7 cm H₂O.

INTERVENTIONS

We applied a protocol of stepwise CPAP level changes, with the overall direction and magnitude guided by individual responses in V'/Q' mismatch, as determined by the degree of right shift (kilopascals, kPa) in a non-invasive gas exchange model. Best CPAP level was defined as the final pressure level at which V'/Q' improved by more than 5%.

MAIN OUTCOME MEASURES

Within-subject change in V'/Q' mismatch between baseline and best CPAP levels.

RESULTS

There was a median (IQR) within-subject reduction in V'/Q' mismatch of 1.2 (0-3.2) kPa between baseline and best CPAP levels, p=0.02. Best CPAP was observed at a median (range) absolute level of 7 (5-8) cm H₂O.

CONCLUSIONS

Non-invasive measures of V'/Q' mismatch may be a useful approach for identifying individualised CPAP levels in preterm infants. The results of our feasibility study should be interpreted cautiously and replication in larger studies evaluating the impact of this approach on clinical outcomes is needed.

TRIAL REGISTRATION NUMBER

NCT02983825.

Quality improvement methods - Part II

To solve complex problems in healthcare, providers need the will to make change, well thought-out or evidence-based ideas, and a quality improvement methodology for executing those ideas. This review will focus on specific elements of execution. A previous review by Picarillo (1) discussed the Model for Improvement, process maps, Pareto charts, Ishikawa diagrams, and driver diagrams. Here, Lean/Six Sigma (LSS) is introduced as an additional methodology for quality improvement (QI), including a selected discussion of some associated LSS tools. Specifically, the Failure Modes and Effects Analysis (FMEA) will be reviewed in more detail. This is a tool to proactively identify possible errors in processes of care, prioritize those which may have the biggest impact if they reached the patient, and develop action plans to address them. Finally, Planned Experimentation is presented as a mechanism to organize your testing strategy for ideas for change. Having an understanding of the concepts in this review and that by Picarillo (1) will provide a sound foundation in the methodology and tools needed to address quality problems in healthcare.

Nitric Oxide and Cellular Maturity Are Key Components of Pro-Inflammatory Cytokine-Induced Apoptosis of Human Fetal Lung Epithelial Cells

Inflammation is a major contributor to the pathogenesis of bronchopulmonary dysplasia (BPD). BPD is associated with prematurity of birth, sepsis, with increased production of both cytokines and nitric oxide, and with the shedding of bronchial epithelial cells. The pathological mechanisms involved in this disease remain unclear, in particular the role that epithelial maturity plays. The effects of pro-inflammatory cytokines upon immature and mature cells are examined within this study, using primary culture of human lung epithelial cells. Pro-inflammatory cytokines increase inducible nitric oxide synthase (iNOS) expression and raise NO production, irrespective of cellular maturity. Pre-incubation with 1400W, a specific iNOS inhibitor, abrogated pro-inflammatory cytokine-induced NO generation and apoptosis. However, immature fetal lung epithelial cells were uniquely sensitive to cellular injury in response to cytokine exposure. These observations suggest that pro-inflammatory cytokines, which are present within BPD, may cause apoptosis of lung epithelial cells via de novo generation of NO. Furthermore, the prematurity of lung epithelial cells may be a factor in free radical mediated pulmonary damage.

Adverse neonatal outcomes: examining the risks between preterm, late preterm, and term infants

OBJECTIVE

There is a relative paucity of data regarding neonatal outcomes in the late preterm cohort (34 to 36 6/7 weeks). This study sought to assess differences in adverse outcomes between infants delivering 32 to 33 6/7, 34 to 36 6/7 weeks, and 37 weeks or later.

STUDY DESIGN

Data were collected as part of a retrospective cohort study of preterm labor patients (2002-2005). Patients delivering 32 weeks or later were included (n = 264). The incidence of adverse outcomes was assessed. Significant associations between outcomes and gestational age at delivery were determined using chi(2) analyses and Poisson regression modeled cumulative incidence and controlled for confounders.

RESULTS

Late preterm infants have increased risk of adverse outcomes, compared with term infants. Controlling for confounders, there was a 23% decrease in adverse outcomes with each week of advancing gestational age between 32 and 39 completed weeks (relative risk 0.77, P < .001, 95% confidence interval, 0.71-0.84).

CONCLUSION

Further investigation regarding obstetrical management and long-term outcomes for this cohort is warranted.

Biological significance of nitric oxide-mediated protein modifications

Nitric oxide (NO), despite an apparently simple diatomic structure, has a wide variety of functions in both physiology and pathology and within every major organ system. It has become an increasingly important scientific challenge to decipher how this wide range of activity is achieved. To this end a number of investigators have begun to explore how NO-mediated posttranslational modifications of proteins may represent mechanisms of cellular signaling. These modifications include: 1). binding to metal centers; 2). nitrosylation of thiol and amine groups; 3). nitration of tyrosine, tryptophan, amine, carboxylic acid, and phenylalanine groups; and 4). oxidation of thiols (both cysteine and methionine residues) and tyrosine. However, two particular modifications have recently received much attention, nitrosylation of thiols to produce S-nitrosothiol and nitration of tyrosine residues to produce nitrotyrosine. It is the purpose of this review to examine the possibility that these modifications may play a role in NO-mediated signaling.