Volume-targeted versus pressure-limited ventilation for preterm infants: a systematic review and meta-analysis

Ventilation practices in the neonatal intensive care units in Saudi Arabia, survey of the utilization of volume-targeted ventilation among practicing neonatologists

OBJECTIVE

To assess the current practice in using volume-targeted ventilation among neonatologists working at the Neonatal Intensive Care Units (NICU) of Saudi Arabia.

METHODS

The questionnaire was provided electronically to 153 practicing Neonatologists working in 39 NICUs. The survey's results were received and statistically analyzed.

RESULTS

One hundred nineteen (119) responses were received with, a 78% response rate. Volume Targeted Ventilation (VTV) was used routinely by 67.2%, whereas 21.8% still use only pressure control (PC)/pressure limited (PL) mode. During the acute phase of ventilation support, Assist Control was the most popular synchronized mode, whereas Synchronized Intermittent Mandatory Ventilation (SIMV) with pressure support (PS) or PSV were the two most common modes during the weaning phase, 31.8%, and 31% respectively. The majority of the neonatologists used a tidal volume of 4 ml/kg as the lowest and 6 ml/kg as the highest. The major reasons for not implementing VTV were the limited availability of ventilator devices that have an option of VTV, followed by lack of experience.

CONCLUSION

VTV is the predominant ventilation practice approach among neonatologists working in the KSA. Limited availability and lack of experience in using are the main challenges. Efforts to equip NICUs with the most advanced ventilation technology, enhance practitioners' experience and sufficient training in its use are warranted.

Artesunate Alleviates Hyperoxia-Induced Lung Injury in Neonatal Mice by Inhibiting NLRP3 Inflammasome Activation

Bronchopulmonary dysplasia (BPD) is a chronic respiratory disease in preterm infants that may cause persistent lung injury. Artesunate exhibits excellent anti-inflammatory in lung injury caused by various factors. This study aimed to investigate the effect of the artesunate on hyperoxia-induced lung injury in neonatal mice and its mechanism. A BPD model of hyperoxic lung injury in neonatal mice was established after hyperoxia (75% oxygen) exposure for 14 days, and part of the mice received intraperitoneal injections of the artesunate. H&E staining was used to observe the pathology of lung tissue, and the degree of oxidative stress in the lung tissue was determined by commercial kits. The levels of inflammatory cytokines in the serum and lung tissues of neonatal mice were detected by an enzyme-linked immunosorbent assay. Immunohistochemical experiments were performed to further evaluate the expression of IL-1β. The real-time quantitative polymerase chain reaction was used to determine the mRNA level of the NLRP3 inflammasome. The western blot assay was used to measure the levels of NLRP3 inflammasome and NF-κB pathway-related proteins. Artesunate ameliorated weight loss and lung tissue injury in neonatal mice induced by hyperoxia. The level of malondialdehyde was decreased, while the activity of superoxide dismutase and the level of glutathione increased after artesunate treatment. Artesunate reduced the level of inflammation cytokines TNF-α, IL-6, and IL-1β in the serum and lung. Moreover, artesunate inhibited the mRNA expression and protein levels of NLRP3, ASC, and caspase-1, as well as the phosphorylation of the NF-κB and IκBα. Our findings suggest that artesunate treatment can attenuate hyperoxia-induced lung injury in BPD neonatal mice by inhibiting the activation of NLRP3 inflammasome and the phosphorylation of the NF-κB pathway.

Understanding pediatric ventilation in the operative setting. Part II: Setting perioperative ventilation

Approaches toward lung-protective ventilation have increasingly been investigated in recent years. Despite evidence being found in adults undergoing surgery, data in younger children are still scarce and controversial. From a physiological perspective, however, the continuously changing characteristics of the respiratory system from birth through adolescence require an approach based on the analysis of each individual patient. The modern anesthesia workstation provides such information, with the technical strengths and weaknesses being discussed in a review preceding the present work (see Part I). The present summary aims to provide ideas on how to translate the information displayed on the anesthesia workstation to patient-oriented clinical ventilation settings.

Tidal Volume in Pediatric Ventilation: Do You Get What You See?

Mechanical ventilators are increasingly evolving into computer-driven devices. These technical advancements have impact on clinical decisions in pediatric intensive care units (PICUs). A good understanding of the design of mechanical ventilators can improve clinical care. Tidal volume (TV) is one of the corner stones of ventilation: multiple technical factors influence the TV and, thus, influence clinical decision making. Ventilator manufacturers make various design choices regarding the phase, site and conditions of TV measurement as well as algorithmic processing choices. Such choice may impact the measurement and subsequent display of TV. A software change of the TV measuring algorithm of the SERVO-i^® (Getinge, Solna, Sweden) at the PICU of the University Medical Centre Utrecht was studied in a prospective cohort. It showed, as example, a clinically significant impact of 8% difference in reported TV. Design choices in both the hardware and software of mechanical ventilators can have a clinically relevant impact on the measurement of tidal volume. In our search for the optimal TV for lung-protective ventilation, such choices should be taken into account.

Nasal continuous positive airway pressure levels for the prevention of morbidity and mortality in preterm infants

BACKGROUND

Preterm infants are at risk of lung atelectasis due to various anatomical and physiological immaturities, placing them at high risk of respiratory failure and associated harms. Nasal continuous positive airway pressure (CPAP) is a positive pressure applied to the airways via the nares. It helps prevent atelectasis and supports adequate gas exchange in spontaneously breathing infants. Nasal CPAP is used in the care of preterm infants around the world. Despite its common use, the appropriate pressure levels to apply during nasal CPAP use remain uncertain.

OBJECTIVES

To assess the effects of 'low' (≤ 5 cm H₂O) versus 'moderate-high' (> 5 cm H₂O) initial nasal CPAP pressure levels in preterm infants receiving CPAP either: 1) for initial respiratory support after birth and neonatal resuscitation or 2) following mechanical ventilation and endotracheal extubation.

SEARCH METHODS

We ran a comprehensive search on 6 November 2020 in the following databases: CENTRAL via CRS Web and MEDLINE via Ovid. We also searched clinical trials databases and the reference lists of retrieved articles for randomized controlled trials (RCTs) and quasi-randomized trials.

SELECTION CRITERIA

We included RCTs, quasi-RCTs, cluster-RCTs and cross-over RCTs randomizing preterm infants of gestational age < 37 weeks or birth weight < 2500 grams within the first 28 days of life to different nasal CPAP levels.

DATA COLLECTION AND ANALYSIS

We used the standard methods of Cochrane Neonatal to collect and analyze data. We used the GRADE approach to assess the certainty of the evidence for the prespecified primary outcomes.

MAIN RESULTS

Eleven trials met inclusion criteria of the review. Four trials were parallel-group RCTs reporting our prespecified primary or secondary outcomes. Two trials randomized 316 infants to low versus moderate-high nasal CPAP for initial respiratory support, and two trials randomized 117 infants to low versus moderate-high nasal CPAP following endotracheal extubation. The remaining seven studies were cross-over trials reporting short-term physiological outcomes. The most common potential sources of bias were absent or unclear blinding of personnel and assessors and uncertain selective reporting. Nasal CPAP for initial respiratory support after birth and neonatal resuscitation None of the six primary outcomes prespecified for inclusion in the summary of findings was eligible for meta-analysis. No trials reported on moderate-severe neurodevelopmental impairment at 18 to 26 months. The remaining five outcomes were reported in a single trial. On the basis of this trial, we are uncertain whether low or moderate-high nasal CPAP levels improve the outcomes of: death or bronchopulmonary dysplasia (BPD) at 36 weeks' postmenstrual age (PMA) (risk ratio (RR) 1.02, 95% confidence interval (CI) 0.56 to 1.85; 1 trial, 271 participants); mortality by hospital discharge (RR 1.04, 95% CI 0.51 to 2.12; 1 trial, 271 participants); BPD at 28 days of age (RR 1.10, 95% CI 0.56 to 2.17; 1 trial, 271 participants); BPD at 36 weeks' PMA (RR 0.80, 95% CI 0.25 to 2.57; 1 trial, 271 participants), and treatment failure or need for mechanical ventilation (RR 1.00, 95% CI 0.63 to 1.57; 1 trial, 271 participants). We assessed the certainty of the evidence as very low for all five outcomes due to risk of bias, a lack of consistency across multiple studies, and imprecise effect estimates. Nasal CPAP following mechanical ventilation and endotracheal extubation One of the six primary outcomes prespecified for inclusion in the summary of findings was eligible for meta-analysis. On the basis of these data, we are uncertain whether low or moderate-high nasal CPAP levels improve the outcome of treatment failure or need for mechanical ventilation (RR 1.52, 95% CI 0.92 to 2.50; 2 trials, 117 participants; I² = 17%; risk difference 0.15, 95% CI -0.02 to 0.32; number needed to treat for an additional beneficial outcome 7, 95% CI -50 to 3). We assessed the certainty of the evidence as very low due to risk of bias, inconsistency across the studies, and imprecise effect estimates. No trials reported on moderate-severe neurodevelopmental impairment at 18 to 26 months or BPD at 28 days of age. The remaining three outcomes were reported in a single trial. On the basis of this trial, we are uncertain whether low or moderate-high nasal CPAP levels improve the outcomes of: death or BPD at 36 weeks' PMA (RR 0.87, 95% CI 0.51 to 1.49; 1 trial, 93 participants); mortality by hospital discharge (RR 2.94, 95% CI 0.12 to 70.30; 1 trial, 93 participants), and BPD at 36 weeks' PMA (RR 0.87, 95% CI 0.51 to 1.49; 1 trial, 93 participants). We assessed the certainty of the evidence as very low for all three outcomes due to risk of bias, a lack of consistency across multiple studies, and imprecise effect estimates.  AUTHORS' CONCLUSIONS: There are insufficient data from randomized trials to guide nasal CPAP level selection in preterm infants, whether provided as initial respiratory support or following extubation from invasive mechanical ventilation. We are uncertain as to whether low or moderate-high nasal CPAP levels improve morbidity and mortality in preterm infants. Well-designed trials evaluating this important aspect of a commonly used neonatal therapy are needed.

The Intertemporal Role of Respiratory Support in Improving Neonatal Outcomes: A Narrative Review

Defining improvements in healthcare can be challenging due to the need to assess multiple outcomes and measures. In neonates, although progress in respiratory support has been a key factor in improving survival, the same degree of improvement has not been documented in certain outcomes, such as bronchopulmonary dysplasia. By exploring the evolution of neonatal respiratory care over the last 60 years, this review highlights not only the scientific advances that occurred with the application of invasive mechanical ventilation but also the weakness of the existing knowledge. The contributing role of non-invasive ventilation and less-invasive surfactant administration methods as well as of certain pharmacological therapies is also discussed. Moreover, we analyze the cost-benefit of neonatal care-respiratory support and present future challenges and perspectives.

Development of an artificial placenta for support of premature infants: narrative review of the history, recent milestones, and future innovation

Over 50 years ago, visionary researchers began work on an extracorporeal artificial placenta to support premature infants. Despite rudimentary technology and incomplete understanding of fetal physiology, these pioneering scientists laid the foundation for future work. The research was episodic, as medical advances improved outcomes of premature infants and extracorporeal life support (ECLS) was introduced for the treatment of term and near-term infants with respiratory or cardiac failure. Despite ongoing medical advances, extremely premature infants continue to suffer a disproportionate burden of mortality and morbidity due to organ immaturity and unintended iatrogenic consequences of medical treatment. With advancing technology and innovative approaches, there has been a resurgence of interest in developing an artificial placenta to further diminish the mortality and morbidity of prematurity. Two related but distinct platforms have emerged to support premature infants by recreating fetal physiology: a system based on arteriovenous (AV) ECLS and one based on veno-venous (VV) ECLS. The AV-ECLS approach utilizes only the umbilical vessels for cannulation. It requires immediate transition of the infant at the time of birth to a fluid-filled artificial womb to prevent umbilical vessel spasm and avoid gas ventilation. In contradistinction, the VV-ECLS approach utilizes the umbilical vein and the internal jugular vein. It would be applied after birth to infants failing maximal medical therapy or preemptively if risk stratified for high mortality and morbidity. Animal studies are promising, demonstrating prolonged support and ongoing organ development in both systems. The milestones for clinical translation are currently being evaluated.

Lung Ultrasound in Bronchopulmonary Dysplasia: Patterns and Predictors in Very Preterm Infants

INTRODUCTION

Lung ultrasound (LUS) is useful for respiratory management in very preterm infants (VPI), but little is known about the echographic patterns in bronchopulmonary dysplasia (BPD), the relation between the image findings, and the severity of the disease and its long-term outcomes. We aimed to describe LUS patterns in BPD and analyze the accuracy of LUS to predict the need for respiratory support at 36 weeks postmenstrual age (PMA) in VPI.

METHODS

Preterm infants ≤30.6 weeks of gestational age were recruited. LUS was performed at admission, at 7th, and 28th day of life (DOL) with a standardized protocol (6 zones: anterior, lateral, and posterior fields). Clinical data, respiratory outcomes, and image findings were recorded.

RESULTS

Eighty-nine patients were studied. Infants with BPD had significantly higher LUS score at admission, at 7th, and 28th DOL. Patients with BPD exhibited more consolidations and pleural line abnormalities at 7th and 28th DOL than those without BPD (p < 0.001), regardless of the definition used for BPD. LUS at 7th DOL predicted NICHD 2001-BPD with R2 = 0.522; AUC = 0.87 (0.79-0.94), p < 0.001, and Jensen 2019-BPD with R2 = 0.315 (AUC = 0.80 [0.70-0.90], p < 0.001). A model including mechanical ventilation >5 days, oxygen therapy for 7 days and LUS score at 7th DOL accurately predicted the need for respiratory support at 36 weeks PMA (R2 = 0.655, p < 0.001) with an AUC = 0.90 (0.84-0.97), p < 0.001.

CONCLUSION

LUS score, pleural line abnormalities, and consolidations can be useful to diagnose BPD in VPI and to predict its severity after the first week of life.

Lung disease and pulmonary hypertension in the premature infant

The premature infant is born into the world unprepared to naturally thrive in a foreign environment. Lung development entails immense growth, structural remodeling and differentiation of specialized cells during the normal term perinatal and postnatal periods. Thus, the premature infant presents with a lung deficient for appropriate respiration. Disruption of lung development seen in bronchopulmonary dysplasia (BPD) and chronic lung disease (CLD) results in not only impaired airway growth but also a deficiency in the accompanying vasculature including the capillary system required for gas exchange. Deficient vascular area can lead to elevated pulmonary vascular resistance and the development of pulmonary hypertension (PH). Unlike PH seen in children and adults with pulmonary arterial hypertension (PAH), treatment with conventional pulmonary vasodilators can be limited in developmental lung disease-associated PH because there are fewer blood vessels to dilate. In this brief review, we highlight some of the knowledge on PH in the premature infant presented at the Proceedings of the 22^nd Annual Update on Pediatric and Congenital Cardiovascular Disease.

The Difference Between Set and Delivered Tidal Volume: A Lung Simulation Study

Background

Precise control of tidal volume is one of the keys in limiting ventilator-induced lung injury and ensuring adequate ventilation in mechanically ventilated neonates. The aim of the study was to compare the tidal volume (mVT) measured from the expiratory limb of the ventilator with the actual tidal volume (aVT) that would be delivered to the patient using a lung model to simulate a neonate.

Methods

This study was conducted using the ASL5000 lung simulator. Three combinations of parameters were set: resistance (cmH₂O/L/sec) and compliance (mL/cmH₂O) of 50 and 2 (Group 1), 100 and 1 (Group 2), and 150 and 0.5 (Group 3), respectively. The ASL5000 was connected to each of the ventilators including one anesthesia machine ventilator (Drager Fabius GS) and two ICU ventilators (Servo-i Universal and Evita Infinity V500). Each ventilator was evaluated with a set tidal volume of 30 mL (sVT) and a respiratory rate of 25 breathes/minute in both the volume-controlled ventilation (VCV) and dual-controlled ventilation (DCV) modes.

Results

The discrepancies between sVT, mVT and aVT were highest with the Fabius anesthesia machine ventilator and increased in the simulated lung injury groups. When comparing the ICU ventilators, the difference was greater the Servo-i and increased when using the DCV mode and with simulated lung injury.

Conclusion

Accurate tidal volumes were achieved only with the Infinity ICU ventilator. This was true regardless of mode of ventilation and even during simulated lung injury.

Effect of high-frequency oscillatory ventilation combined with volume guarantee on preterm infants with hypoxic respiratory failure

BACKGROUND

The aim of this study was to assess the effect of volume guarantee (VG) on high-frequency oscillatory ventilation (HFOV) compared with HFOV alone in preterm infants with hypoxic respiratory failure (HRF).

METHODS

Fifty-two preterm infants with HRF refractory to conventional mechanical ventilation (CMV) were enrolled in this study. Between June 2012 and February 2016, HFOV alone was used as rescue therapy when CMV failed for 34 infants, whereas HFOV combined with VG was used as rescue therapy for the other 18 infants between March 2016 and December 2017.

RESULTS

HFOV combined with VG resulted in a reduction in the combined outcome of death or bronchopulmonary dysplasia (BPD) (p = 0.017) and also a reduction in episodes of hypercarbia (p = 0.010) compared with HFOV alone.

CONCLUSION

In this study, the preterm infants with HRF ventilated using HFOV combined with VG had a reduced combined outcome of death or BPD and hypercarbia compared with those who received HFOV alone.

Volume-targeted versus pressure-limited ventilation for preterm infants

BACKGROUND

To compare the effects of volume-targeted ventilation (VTV) with pressure-limited ventilation (PLV) in preterm infants.

METHODS

A total of 100 preterm infants who required mechanical ventilation during the two study periods were investigated. PLV was used for 50 preterm infants during period 1 and VTV was used for 50 preterm infants during period 2. Clinical outcomes including mortality rate, duration of mechanical ventilation, air leak syndrome, hypocarbia, hypercarbia, hypoxemia, combined outcome of death or bronchopulmonary dysplasia (BPD), intraventricular hemorrhage, and retinopathy of prematurity were evaluated.

RESULTS

There was no significant difference (p > 0.05) in the duration of mechanical ventilation, air leak syndrome, hypocarbia, hypoxemia, or BPD between the two study groups. The mortality rate, hypercarbia, and combined outcome of death or BPD were significantly lower (p < 0.05) in the VTV group compared with the PLV group.

CONCLUSION

Preterm infants using VTV had a lower mortality rate, less hypercarbia, and a significant decrease in the combined outcome of death or BPD.

A dedicated respiratory function monitor to improve tidal volume delivery during neonatal anesthesia

BACKGROUND

Tight control of tidal volume using accurate monitoring may improve neonatal outcomes. However, respiratory function monitors incorporated in current anesthetic workstations are generally inaccurate at tidal volumes used for infants.

AIMS

To determine if a specific respiratory function monitor for neonatal infants improved expired tidal volume delivery during anesthesia.

METHOD

Infants <3 months old requiring intubation for surgery in the operating theater were studied. After intubation a Phillips NM3, Acutronic Florian, or Novametrix Ventcheck Respiratory Function Monitor was integrated into the circuit, and clinicians given access to the display for the duration of anesthesia. Breath-to-breath expired tidal volume delivery, leak, and delivered pressure were recorded, with cardiorespiratory parameters. These were compared with a matched control group with clinicians blinded to respiratory function monitor display.

RESULTS

A total of 10 055 and 2569 inflations were measured in the respiratory function monitor visible (n = 32) and masked (n = 33) groups, respectively, with mean (standard deviation) delivered expired tidal volume 7.5 (2.4) mL/kg and 7.7 (3.0) mL/kg, respectively; mean difference (95% confidence interval) -0.2 (-1.1, 0.8) mL/kg (Welch's t test). In the visible group, 55.6% of expired tidal volumes were between 4 and 8 mL/kg compared to 51.7% in the masked group; relative benefit (95% confidence interval), 1.08 (1.03, 1.12). Expired tidal volume was less likely to be <4 mL/kg in the visible group compared to masked group; 6.4% vs 9.8%, 1.53 (1.33, 1.76). The use of a respiratory function monitor also reduced the number of inflations >10 mL/kg; 13.0% vs 22.0%, 1.11 (1.09, 1.14).

CONCLUSION

Tidal volumes <4 mL/kg and >10 mL/kg are frequently delivered during neonatal anesthesia. The inclusion of an accurate respiratory function monitor may reduce the risk of exposure to potentially harmful tidal volumes.

Bronchopulmonary Dysplasia and Pulmonary Outcomes of Prematurity

Bronchopulmonary dysplasia (BPD) is a chronic lung disease most commonly seen in premature infants who require mechanical ventilation and oxygen therapy. Despite advances in neonatal care resulting in improved survival and decreased morbidity, limited progress has been made in reducing rates of BPD. Therapeutic options to protect the vulnerable developing lung are limited as are strategies to treat lung injury, resulting in ongoing concerns for long-term pulmonary morbidity after preterm birth. Lung protective strategies and optimal nutrition are recognized to improve pulmonary outcomes. However, characterization of late outcomes is challenged by rapid advances in neonatal care. As a result, current adult survivors reflect outdated medical practices. Although neonatal pulmonary disease tends to improve with growth, compromised respiratory health has been documented in young adult survivors of BPD. With improved survival of premature infants but limited progress in reducing rates of disease, BPD represents a growing burden on health care systems. [Pediatr Ann. 2019;48(4):e148-e153.].

Impact of delivered tidal volume on the occurrence of intraventricular haemorrhage in preterm infants during positive pressure ventilation in the delivery room

BACKGROUND AND OBJECTIVES

Delivery of inadvertent high tidal volume (V_T) during positive pressure ventilation (PPV) in the delivery room is common. High V_T delivery during PPV has been associated with haemodynamic brain injury in animal models. We examined if V_T delivery during PPV at birth is associated with brain injury in preterm infants <29 weeks' gestation.

METHODS

A flow-sensor was placed between the mask and the ventilation device. V_T values were compared with recently described reference ranges for V_T in spontaneously breathing preterm infants at birth. Infants were divided into two groups: V_T<6  mL/kg or V_T>6 mL/kg (normal and high V_T, respectively). Brain injury (eg, intraventricular haemorrhage (IVH)) was assessed using routine ultrasound imaging within the first days after birth.

RESULTS

A total of 165 preterm infants were included, 124 (75%) had high V_T and 41 (25%) normal V_T. The mean (SD) gestational age and birth weight in high and normal V_T group was similar, 26 (2) and 26 (1) weeks, 858 (251) g and 915 (250) g, respectively. IVH in the high V_T group was diagnosed in 63 (51%) infants compared with 5 (13%) infants in the normal V_T group (P=0.008).Severe IVH (grade III or IV) developed in 33/124 (27%) infants in the high V_T group and 2/41 (6%) in the normal V_T group (P=0.01).

CONCLUSIONS

High V_T delivery during mask PPV at birth was associated with brain injury. Strategies to limit V_T delivery during mask PPV should be used to prevent high V_T delivery.

Endothelial Extracellular Vesicles in Pulmonary Function and Disease

The pulmonary vascular endothelium is involved in the pathogenesis of acute and chronic lung diseases. Endothelial cell (EC)-derived products such as extracellular vesicles (EVs) serve as EC messengers that mediate inflammatory as well as cytoprotective effects. EC-EVs are a broad term, which encompasses exosomes and microvesicles of endothelial origin. EVs are comprised of lipids, nucleic acids, and proteins that reflect not only the cellular origin but also the stimulus that triggered their biogenesis and secretion. This chapter presents an overview of the biology of EC-EVs and summarizes key findings regarding their characteristics, components, and functions. The role of EC-EVs is specifically delineated in pulmonary diseases characterized by endothelial dysfunction, including pulmonary hypertension, acute respiratory distress syndrome and associated conditions, chronic obstructive pulmonary disease, and obstructive sleep apnea.

[A comparative study of two ventilation modes in the weaning phase of preterm infants with respiratory distress syndrome]

OBJECTIVE

To compare the efficacy between synchronized intermittent mandatory ventilation (SIMV) and pressure support ventilation with volume guarantee (PSV+VG) in the weaning phase of preterm infants with respiratory distress syndrome (RDS).

METHODS

Forty preterm infants with RDS who were admitted to the neonatal intensive care unit between March 2016 and May 2017 were enrolled as subjects. All infants were born at less than 32 weeks' gestation and received mechanical ventilation. These patients were randomly and equally divided into SIMV group and PSV+VG group in the weaning phase. Ventilator parameters, arterial blood gas, weaning duration (from onset of weaning to extubation), duration of nasal continuous positive airway pressure (NCPAP) after extubation, extubation failure rate, the incidence rates of pneumothorax, patent ductus arteriosus (PDA) and bronchopulmonary dysplasia (BPD), and the mortality rate were compared between the two groups.

RESULTS

The PSV+VG group had significantly decreased mean airway pressure, weaning duration, duration of NCPAP after extubation, and extubation failure rate compared with the SIMV group (P<0.05). There were no significant differences in arterial blood gas, mortality, or incidence rates of pneumothorax, PDA and BPD between the two groups (P>0.05).

CONCLUSIONS

For preterm infants with RDS, the PSV+VG mode may be a relatively safe and effective mode in the weaning phase. However, multi-center clinical trials with large sample sizes are needed to confirm the conclusion.

Preventing Continuous Positive Airway Pressure Failure: Evidence-Based and Physiologically Sound Practices from Delivery Room to the Neonatal Intensive Care Unit

Routine use of continuous positive airway pressure (CPAP) to support preterm infants with respiratory distress is an evidenced-based strategy to decrease incidence of bronchopulmonary dysplasia. However, rates of CPAP failure remain unacceptably high in very premature neonates, who are at high risk for developing bronchopulmonary dysplasia. Using the GRADE framework to assess the quality of available evidence, this article reviews strategies aimed at decreasing CPAP failure, starting with delivery room interventions and followed through to system-based efforts in the neonatal intensive care unit. Despite best efforts, some very premature neonates fail CPAP. Also reviewed are predictors of CPAP failure in this vulnerable population.

How best to capture the respiratory consequences of prematurity?

Chronic respiratory morbidity is a common complication of premature birth, generally defined by the presence of bronchopulmonary dysplasia, both clinically and in trials of respiratory therapies. However, recent data have highlighted that bronchopulmonary dysplasia does not correlate with chronic respiratory morbidity in older children born preterm. Longitudinally evaluating pulmonary morbidity from early life through to childhood provides a more rational method of defining the continuum of chronic respiratory morbidity of prematurity, and offers new insights into the efficacy of neonatal respiratory interventions. The changing nature of preterm lung disease suggests that a multimodal approach using dynamic lung function assessment will be needed to assess the efficacy of a neonatal respiratory therapy and predict the long-term respiratory consequences of premature birth. Our aim is to review the literature regarding the long-term respiratory outcomes of neonatal respiratory strategies, the difficulties of assessing dynamic lung function in infants, and potential new solutions.

Better measures are needed to predict chronic respiratory morbidity in survivors born prematurely http://ow.ly/1L3n30ihq9C

Accuracy of near-patient vs. inbuilt spirometry for monitoring tidal volumes in an in-vitro paediatric lung model

Spirometric monitoring provides precise measurement and delivery of tidal volumes within a narrow range, which is essential for lung-protective strategies that aim to reduce morbidity and mortality in mechanically-ventilated patients. Conventional anaesthesia ventilators include inbuilt spirometry to monitor inspiratory and expiratory tidal volumes. The GE Aisys CS² anaesthesia ventilator allows additional near-patient spirometry via a sensor interposed between the proximal end of the tracheal tube and the respiratory tubing. Near-patient and inbuilt spirometry of two different GE Aisys CS² anaesthesia ventilators were compared in an in-vitro study. Assessments were made of accuracy and variability in inspiratory and expiratory tidal volume measurements during ventilation of six simulated paediatric lung models using the ASL 5000 test lung. A total of 9240 breaths were recorded and analysed. Differences between inspiratory tidal volumes measured with near-patient and inbuilt spirometry were most significant in the newborn setting (p < 0.001), and became less significant with increasing age and weight. During expiration, tidal volume measurements with near-patient spirometry were consistently more accurate than with inbuilt spirometry for all lung models (p < 0.001). Overall, the variability in measured tidal volumes decreased with increasing tidal volumes, and was smaller with near-patient than with inbuilt spirometry. The variability in measured tidal volumes was higher during expiration, especially with inbuilt spirometry. In conclusion, the present in-vitro study shows that measurements with near-patient spirometry are more accurate and less variable than with inbuilt spirometry. Differences between measurement methods were most significant in the smallest patients. We therefore recommend near-patient spirometry, especially for neonatal and paediatric patients.

Recent Advances in Bronchopulmonary Dysplasia: Pathophysiology, Prevention, and Treatment

Bronchopulmonary dysplasia (BPD) is potentially one of the most devastating conditions in premature infants with longstanding consequences involving multiple organ systems including adverse effects on pulmonary function and neurodevelopmental outcome. Here we review recent studies in the field to summarize the progress made in understanding in the pathophysiology, prognosis, prevention, and treatment of BPD in the last decade. The work reviewed includes the progress in understanding its pathobiology, genomic studies, ventilatory strategies, outcomes, and therapeutic interventions. We expect that this review will help guide clinicians to treat premature infants at risk for BPD better and lead researchers to initiate further studies in the field.

Effect of ventilator mode on patient-ventilator synchrony and work of breathing in neonatal pigs

BACKGROUND

Patient-ventilator asynchrony can result in increased work of breathing (WOB) and need for increased sedation, as well as respiratory muscle fatigue and prolonged mechanical ventilation. Different ventilator modes may result in varying degrees of asynchrony and WOB.

OBJECTIVE

The objectives of this study were to assess the incidence of asynchrony and the effect of asynchrony on WOB in three modes of ventilation: pressure regulated volume control (PRVC), synchronized intermittent mandatory ventilation/volume control plus pressure support (SIMV/VC plus PS), and SIMV/PRVC plus PS.

METHODS

Ten piglets (2.1 ± 0.3 kg) were studied, each in the healthy and surfactant-depleted, lung-injured state. Piglets were sedated, intubated, and ventilated with the three modes of ventilation randomly applied. Piglets then underwent surfactant washout, after which the lungs were re-recruited, and the modes of ventilation were repeated. Airway flow and pressure waveforms were acquired via pneumotachograph. Waveforms were analyzed for patient-ventilator asynchrony and pressure time product (PTP) as an estimate of patient WOB. RESULTS SIMV/VC plus PS had the highest incidence of asynchrony. The incidence of asynchrony was less in the injured lung. PTP (cm H₂ O*S) was increased for SIMV/VC plus PS (healthy 0.10 ± 0.12; injured 0.15 ± 0.13) compared to PRVC (healthy 0.05 ± 0.05; injured 0.06 ± 0.03), (P < 0.03) in both the healthy and injured lung models.

CONCLUSIONS

Asynchrony and WOB are highest with SIMV/VC plus PS. If SIMV is utilized, SIMV/PRVC plus a PS that optimizes tidal volume may be preferable. PRVC has the least asynchrony and WOB in the injured lung.

Lung-protective ventilatory strategies in intubated preterm neonates with RDS

This article provides a narrative review of lung-protective ventilatory strategies (LPVS) in intubated preterm infants with RDS. A description of strategies is followed by results on short-and long-term respiratory and neurodevelopmental outcomes. Strategies will include patient-triggered or synchronized ventilation, volume targeted ventilation, the technique of intubation, surfactant administration and rapid extubation to NCPAP (INSURE), the open lung concept, strategies of high-frequency ventilation, and permissive hypercapnia. Based on this review single recommendations on optimal LPVS cannot be made. Combinations of several strategies, individually applied, most probably minimize or avoid potential serious respiratory and cerebral complications like bronchopulmonary dysplasia and cerebral palsy.

Tidal Volume Delivery during the Anesthetic Management of Neonates Is Variable

OBJECTIVES

To describe expiratory tidal volume (V_T) during routine anesthetic management of neonates at a single tertiary neonatal surgical center, as well as the proportion of V_T values within the range of 4.0-8.0 mL/kg.

STUDY DESIGN

A total of 26 neonates needing surgery under general anesthesia were studied, of whom 18 were intubated postoperatively. V_T was measured continuously during normal clinical care using a dedicated neonatal respiratory function monitor (RFM), with clinicians blinded to values. V_T, pressure, and cardiorespiratory variables were recorded regularly while intubated intraoperatively, during postoperative transport, and for 15 minutes after returning to the neonatal intensive care unit (NICU). In addition, paired V_T values from the anesthetic machine were documented intraoperatively.

RESULTS

A total of 2597 V_T measures were recorded from 26 neonates. Intraoperative and postoperative transport expiratory V_T values were highly variable compared with the NICU V_T (P < .0001, Kruskal-Wallis test), with 51% of inflations outside the 4.0-8.0 mL/kg range (35% and 38% of V_T >8.0 mL/kg, respectively), compared with 29% in the NICU (P < .001, χ² test). The use of a flow-inflating bag resulted in a median (range) V_T of 8.5 mL/kg (range, 5.3-11.4 mL/kg) vs 5.6 ml/kg (range, 4.3-7.9 mL/kg) using a Neopuff T-piece system (P < .0001, Mann-Whitney U test). The mean anesthetic machine expiratory V_T was 3.2 mL/kg (95% CI, -4.5 to 10.8 mL/kg) above RFM.

CONCLUSIONS

V_T is highly variable during the anesthetic care of neonates, and potentially injurious V_T is frequently delivered; thus, we suggest close V_T monitoring using a dedicated neonatal RFM.

Volume-Targeted Ventilation in the Neonate: Benchmarking Ventilators on an Active Lung Model

OBJECTIVE

Mechanically ventilated neonates have been observed to receive substantially different ventilation after switching ventilator models, despite identical ventilator settings. This study aims at establishing the range of output variability among 10 neonatal ventilators under various breathing conditions.

DESIGN

Relative benchmarking test of 10 neonatal ventilators on an active neonatal lung model.

SETTING

Neonatal ICU.

SUBJECTS

Ten current neonatal ventilators.

INTERVENTIONS

Ventilators were set identically to flow-triggered, synchronized, volume-targeted, pressure-controlled, continuous mandatory ventilation and connected to a neonatal lung model. The latter was configured to simulate three patients (500, 1,500, and 3,500 g) in three breathing modes each (passive breathing, constant active breathing, and variable active breathing).

MEASUREMENTS AND MAIN RESULTS

Averaged across all weight conditions, the included ventilators delivered between 86% and 110% of the target tidal volume in the passive mode, between 88% and 126% during constant active breathing, and between 86% and 120% under variable active breathing. The largest relative deviation occurred during the 500 g constant active condition, where the highest output machine produced 147% of the tidal volume of the lowest output machine.

CONCLUSIONS

All machines deviate significantly in volume output and ventilation regulation. These differences depend on ventilation type, respiratory force, and patient behavior, preventing the creation of a simple conversion table between ventilator models. Universal neonatal tidal volume targets for mechanical ventilation cannot be transferred from one ventilator to another without considering necessary adjustments.

Coexistence of Ureaplasma and chorioamnionitis is associated with prolonged mechanical ventilation

BACKGROUND

Both histologic chorioamnionitis (HCAM) and Ureaplasma infection are considered important contributors to perinatal lung injury. We tested the hypothesis that coexistence of maternal HCAM and perinatal Ureaplasma exposure increases the risk of prolonged mechanical ventilation in extremely low-birthweight (ELBW) infants.

METHODS

A retrospective cohort study was carried out of all ELBW infants born between January 2008 and December 2013 at a single academic center. Placental pathology and gastric fluid Ureaplasma data were available for all infants. Culture and polymerase chain reaction were used to detect Ureaplasma in gastric fluid. Prolonged mechanical ventilation was defined as mechanical ventilation that began within 28 days after birth and continued.

RESULTS

Of 111 ELBW infants enrolled, 84 survived beyond 36 weeks of postmenstrual age (PMA) and were included in the analysis. Eighteen infants (21.4%) had both HCAM and Ureaplasma exposure. Seven infants (8.3%) required mechanical ventilation beyond 36 weeks of PMA. Coexistence of HCAM and Ureaplasma in gastric fluid was significantly associated with prolonged mechanical ventilation after adjustment for gestational age, sex, mode of delivery, and use of macrolide antibiotics (OR, 8.7; 95%CI: 1.1-67.2).

CONCLUSIONS

Coexistence of maternal HCAM and perinatal Ureaplasma exposure significantly increases the risk of prolonged mechanical ventilation in ELBW infants.

Liberation from home mechanical ventilation and decannulation in children

BACKGROUND

The prevalence of children requiring outpatient invasive long-term mechanical ventilation is increasing. For some children, liberation from home mechanical ventilation (HMV) and decannulation is the desired outcome. This study describes our experience liberating tracheostomy and HMV (T-HMV) dependent children from respiratory technologies.

METHODS

We reviewed charts of T-HMV dependent children who were cared for at our institution and decannulated between July 1999 and December 2011. Patient characteristics, diagnoses, and important steps leading to decannulation were recorded.

RESULTS

Forty-six children achieved HMV independence and decannulation. The most common indications for T-HMV were lower airway and parenchymal lung disease. The median ages at tracheotomy, initiation of HMV, initiation of tracheostomy collar (TC) trials, HMV independence, and decannulation were 3.5, 6.0, 12.0, 25.5, and 40.5 months, respectively. Twenty-five children (54%) skipped either using a speaking valve, tracheostomy capping, or both without increased likelihood of recannulation. (P = 0.03). Common procedures prior to decannulation were airway surgery, bronchoscopy, and polysomnography (n = 30, 46, and 46 children, respectively). A median of 9.5 clinic visits and 5 hospitalizations occurred from initial hospital discharge to just prior to decannulation. HMV was primarily weaned as an outpatient.

CONCLUSION

Liberation from respiratory technology is a complex, multi-step process that can be accomplished in medically complex children with varying underlying disease processes at relatively young ages. Five major steps (tracheotomy, initiation of HMV, initiation of TC trials, HMV independence, and decannulation) performed in conjunction with clinic visits, procedures, and home nursing support were integral in the successful decannulation process. Pediatr Pulmonol. 2016;51:838-849. © 2016 Wiley Periodicals, Inc.

Chronic lung disease in very low birth weight infants: Persistence and improvement of a quality improvement process in a tertiary level neonatal intensive care unit

OBJECTIVE

We previously demonstrated a significant reduction in our incidence of chronic lung disease in our NICU using potentially better practices of avoiding delivery room endotracheal intubation and using early nasal CPAP. We sought to demonstrate whether these improvements were sustained and or improved over time.

STUDY DESIGN

We conducted a retrospective, cross-sectional analysis of infants 501-1500 grams born at our hospital between 2005 and 2013. Infants born during the 2005-2007, 2008-2010 and 2011-2013 epochs were grouped together, respectively. Descriptive analysis was conducted to determine the number and percent of maternal and neonatal characteristics by year grouping. Chi-squared tests were used to determine whether there were any statistically significant changes in characteristics across year groupings.. Two outcome variables were assessed: a diagnosis of chronic lung disease based on the Vermont Oxford Network definition and being discharged home on supplemental oxygen.

RESULTS

There was a statistically significant improvement in the incidence of chronic lung disease in infants below 27 weeks' gestation in the three year period in the 2011-2013 cohort compared with those in the 2005-2007 cohort. We also found a statistically significant improvement in the number of infants discharged on home oxygen with birth weights 751-1000 grams and infants with gestational age less than 27 weeks in the 2011-2013 cohort compared to the 2005-2007 cohort.

CONCLUSIONS

We demonstrated sustained improvement in our incidence of CLD between 2005 and 2013. We speculate that a multifaceted strategy of avoiding intubation and excessive oxygen in the delivery room, the early use of CPAP, as well as the use of volume targeted ventilation, when needed, may help significantly reduce the incidence of CLD.

Volume Guarantee Ventilation: Effect on Preterm Infants with Frequent Hypoxemia Episodes

BACKGROUND

Preterm infants on mechanical ventilation have spontaneous hypoxemia episodes (HE) triggered by decreases in lung volume and tidal volume (VT). Volume guarantee (VG) is a mode where the ventilator peak pressure is adjusted to keep the exhaled VT at a target level. The effect of VG on HE under routine clinical conditions has not been fully evaluated.

OBJECTIVE

To evaluate the effect of VG on HE in preterm infants in comparison to pressure control (PC) ventilation under routine clinical conditions.

METHODS

Twenty-four mechanically ventilated preterm infants with ≥4 HE of arterial oxygen saturation (SpO2) <75% over 8 h were enrolled. They were studied over 2 consecutive 24-hour periods of VG and PC, in random order.

RESULTS

While the frequency of HE (SpO2 <85% for ≥20 s) did not differ, their duration was reduced during VG. The frequency or duration of severe HE (SpO2 <75% for ≥20 s) did not differ between PC and VG. The proportion of time in severe hypoxemia (SpO2 <75%) during VG did not differ from PC [median: 4.4 (IQR 2.9-5.0) vs. 5.0% (IQR 3.9-6.9), p = 0.44]. The fraction of inspired oxygen (FiO2) was lower during VG compared to PC.

CONCLUSION

The use of VG during routine clinical conditions resulted in a modest reduction in the duration of HE (SpO2 <85%) and FiO2 compared to PC. The use of VG did not reduce the more severe HE.

Ventilation strategies for preventing oxidative stress-induced injury in preterm infants with respiratory disease: an update

Reactive oxygen and nitrogen species are produced by several inflammatory and structural cells of the airways. The lungs of preterm newborns are susceptible to oxidative injury induced by both reactive oxygen and nitrogen species. Increased oxidative stress and imbalance in antioxidant enzymes may play a role in the pathogenesis of inflammatory pulmonary diseases. Preterm infants are frequently exposed to high oxygen concentrations, infections or inflammation; they have reduced antioxidant defense and high free iron levels which enhance toxic radical generation. Multiple ventilation strategies have been studied to reduce injury and improve outcomes in preterm infants. Using lung protective strategies, there is the need to reach a compromise between satisfaction of gas exchange and potential toxicities related to over-distension, derecruitment of lung units and high oxygen concentrations. In this review, the authors summarize scientific evidence concerning oxidative stress as it relates to resuscitation in the delivery room and to the strategies of ventilation.

Accuracy of currently available neonatal respiratory function monitors for neonatal resuscitation

This study aimed to test the accuracy in volume measurements of three available respiratory function monitors (RFMs) for neonatal resuscitation and the effect of changing gas conditions. The Florian, New Life Box Neo-RSD (NLB Neo-RSD) and NICO RFM were tested on accuracy with volumes of 10 and 20 mL and on changes in volume measurements under changing gas conditions (oxygen level 21-100 % and from cold dry air (24 ± 2 °C) to heated humidified air (37 °C). Volume differences >10 % were considered clinically relevant. We found that the mean (SD) volume difference was clinically acceptable for all devices (10, 20 mL): Florian (+8.4 (1.2)%, +8.4 (0.5)%); NLB Neo-RSD (+5.8 (1.1)%, +4.3 (1.4)%); and NICO (-8.2 (0.9)%, -8.7 (0.8)%). Changing from cold dry to heated humidified air increased the volume difference using the Florian (cold dry air, heated humidified air (+5.2 (1.2)%, +12.2 (0.9)%) but not NLB Neo-RSD (+2.0(1.6)%, +3.4(2.8)%) and NICO (-2.3 % (0.8), +0.1 (0.6)%). Similarly, when using heated humidified air, increasing oxygen enlarged increased the volume difference using the Florian (oxygen 21 %, 100 %: +12.2(1.0)%, +19.8(1.1)%), but not NLB Neo-RSD (+0.2(1.9)%, +1.1(2.8)%) and NICO (-5.6(0.9)%, -3.7(0.9)%). Clinically relevant changes occurred when changing both gas conditions (Florian +25.7(1.7)%; NLB Neo-RSD +3.8(2.4)%; NICO -5.7(1.4)%).

CONCLUSION

The available RFMs demonstrated clinically acceptable deviations in volume measurements, except for the Florian when changing gas conditions.

WHAT IS KNOWN

•Respiratory function monitors (RFMs) are increasingly used for volume measurements during respiratory support of infants at birth. •During respiratory support at birth, gas conditions can change quickly, which can influence the volume measurements. What is new: •The available RFMs have clinically acceptable deviations when measuring the accuracy of volume measurements. •The RFM using a hot wire anemometer demonstrated clinically relevant deviations in volume measurements when changing the gas conditions. These deviations have to be taken into account when interpreting the volumes directly at birth.

Less invasive ventilation in extremely low birth weight infants from 1997 to 2011: survey versus evidence

Evidence for target values of arterial oxygen saturation (SaO2), CO2, and pH has changed substantially over the last 20 years. A representative survey concerning treatment strategies in extremely low-birth-weight infants (ELBW) was sent to all German neonatal intensive care units (NICUs) treating ELBW infants in 1997. A follow-up survey was conducted in 2011 and sent to all NICUs in Germany, Austria, and Switzerland. During the observation period, NICUs targeting SaO2 of 80, 85, and 90 % have increased, while units aiming for 94 and 96 % decreased (all p < 0.001). Similarly, NICUs aiming for pH 7.25 or lower increased, while 7.35 or higher decreased (both p < 0.001). Furthermore, more units targeted a CO2 of 50 mmHg (7.3 kPa) or higher (p < 0.001), while fewer targeted 40 or 35 mmHg (p < 0.001). Non-invasive ventilation (NIV) was used in 80.2 % of NICUs in 2011. The most frequently used ventilation modes were synchronized intermittent mandatory ventilation (SIMV) (67.5 %) and intermittent positive pressure ventilation (IPPV) (59.7 %) in 1997 and SIMV (77.2 %) and synchronized intermittent positive pressure ventilation (SIPPV) (26.8 %) in 2011. NICUs reporting frequent or always use of IPPV decreased to 11.0 % (p < 0.001). SIMV (77.2 %) and SIPPV (26.8 %) did not change from 1997 to 2011, while high-frequency oscillation (HFO) increased from 9.1 to 19.7 % (p = 0.018). Differences between countries, level of care, and size of the NICU were minimal.

CONCLUSIONS

Target values for SaO2 decreased, while CO2 and pH increased significantly during the observation period. Current values largely reflect available evidence at time of the surveys.

WHAT IS KNOWN

• Evidence concerning target values of oxygen saturation, CO 2 , and pH in extremely low-birth-weight infants has grown substantially. • It is not known to which extent this knowledge is transferred into clinical practice and if treatment strategies have changed.

WHAT IS NEW

• Target values for oxygen saturation in ELBW infants decreased between 1997 and 2011 while target values for CO 2 and pH increased. • Similar treatment strategies existed in different countries, hospitals of different size, or university versus nonuniversity hospitals in 2011.

Volume guarantee pressure support ventilation in extremely preterm infants and neurodevelopmental outcome at 18 months

OBJECTIVE

Compared with pressure-controlled ventilation (PCV), volume-targeted ventilation is associated with decreased neonatal complications, including the combined outcome of death or bronchopulmonary dysplasia. However, little is known about its effect on neurodevelopmental outcome. We evaluated the hypothesis that as compared with PCV, volume-targeted ventilation reduces the risk of the combined outcome of neurodevelopmental impairment or death in very low birth weight infants.

STUDY DESIGN

We studied a cohort of extremely preterm infants managed with either volume guarantee pressure support ventilation (VGPSV; n=135) or PCV (n=135). Infants were evaluated at 18 months adjusted age with a standardized neurological examination and the Bayley Scales of Infant and Toddler Development-third edition. Logistic regression models were used to evaluate the association of ventilation mode and neurodevelopmental outcome.

RESULT

Rates of pulmonary interstitial emphysema (odds ratio 0.6; 95% confidence limits: 0.4, 0.8), hypotension (odds ratio: 0.7; 95% confidence limits: 0.5, 0.9) and mortality (odds ratio 0.45; 95% confidence limits: 0.22, 0.9) were lower among infants treated with VGPSV. The infants in the VGPSV group had a significantly shorter duration on mechanical ventilation compared with infants in the PCV group (log-rank test P<0.01). Seventy percent (155/221) of survivors were evaluated at 18 months adjusted age. A trend towards benefit for the combined outcome of death or neurodevelopmental impairment was seen in the VGPSV group but did not reach statistical significance (odds ratio: 0.59; 95% confidence limits: 0.32, 1.08).

CONCLUSION

VGPSV was associated with a decreased risk of short-term complications but not long-term developmental impairment in this modest-sized cohort.

Advances in respiratory support for high risk newborn infants

BACKGROUND

A significant proportion of premature infants present with respiratory failure early in life and require supplemental oxygen and some form of mechanical respiratory support.

FINDINGS

Many technical advances in the devices for neonatal respiratory support have occurred in recent years and new management strategies have been developed and evaluated in this population. This article describes some of these novel methods and discusses their application and possible advantages and limitations.

CONCLUSION

Newer methods of respiratory support have led to marked improvement in outcome of premature infants with respiratory failure. Some of these strategies are very promising but further investigation to evaluate their short term efficacy and impact on long term respiratory and other relevant outcomes is needed before wider use.

Nebulized pentoxifylline for reducing the duration of oxygen supplementation in extremely preterm neonates

OBJECTIVE

To evaluate the efficacy and safety of nebulized pentoxifylline for reducing the duration of oxygen supplementation in extremely preterm neonates at high risk of bronchopulmonary dysplasia (BPD).

STUDY DESIGN

Single-center, randomized, double-blind, placebo-controlled trial was conducted. Infants of 23(0) to 27(6) weeks' gestational age requiring mechanical ventilation or ≥30% supplemental oxygen on continuous positive airway pressure at 72-168 hours were randomized to receive 20 mg/kg (1 mL/kg) nebulized pentoxifylline or an equal volume of normal saline placebo every 6 hours for 10 consecutive days via a vibrating mesh nebulizer. The primary outcome was the duration of oxygen supplementation at 40 weeks' postmenstrual age. We used Cox proportional hazards regression modeling to analyze outcomes.

RESULTS

All infants had adequate data for analysis of the primary outcome. Intention-to-treat analysis revealed no differences in duration of oxygen supplementation at 40 weeks' postmenstrual age between pentoxifylline (n=41) and placebo (n=40) groups (median 2262 vs 2160 hours, adjusted hazard ratio: 1.14, 95% CI 0.72-1.80, P=.63). There was no difference in mortality and further secondary outcomes. No adverse effects were noted.

CONCLUSIONS

Nebulized pentoxifylline is safe but did not reduce the duration of oxygen supplementation in extremely preterm infants at high risk of BPD. Dose-ranging studies and large, well-designed clinical trials are required to determine whether the use of nebulized or systemic pentoxifylline as a prophylactic therapy offers small but relevant benefits for prevention of BPD.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12611000145909.

Ventilator-induced lung injury in preterm infants

In preterm infants, the need for intubation and mechanical ventilation is associated with ventilator-induced lung injuries and subsequent bronchopulmonary dysplasia. The aim of the present review was to improve the understanding of the mechanisms of injury that involve cytokine-mediated inflammation to contribute to the development of new preventive strategies. Relevant articles were retrieved from the PubMed database using the search terms "ventilator-induced lung injury preterm", "continuous positive airway pressure", "preterm", and "bronchopulmonary dysplasia". The resulting data and other relevant information were divided into several topics to ensure a thorough, critical view of ventilation-induced lung injury and its consequences in preterm infants. The role of pro-inflammatory cytokines (particularly interleukins 6 and 8 and tumor necrosis factor alpha) as mediators of lung injury was assessed. Evidence from studies conducted with animals and human newborns is described. This evidence shows that brief periods of mechanical ventilation is sufficient to induce the release of pro-inflammatory cytokines. Other forms of mechanical and non-invasive ventilation were also analyzed as protective alternatives to conventional mechanical ventilation. It was concluded that non-invasive ventilation, intubation followed by early surfactant administration and quick extubation for nasal continuous positive airway pressure, and strategies that regulate tidal volume and avoid volutrauma (such as volume guarantee ventilation) protect against ventilator-induced lung injury in preterm infants.

Bronchopulmonary dysplasia early changes leading to long-term consequences

Neonatal chronic lung disease, i.e., bronchopulmonary dysplasia, is characterized by impaired pulmonary development resulting from the impact of different risk factors including infections, hyperoxia, and mechanical ventilation on the immature lung. Remodeling of the extracellular matrix, apoptosis as well as altered growth factor signaling characterize the disease. The immediate consequences of these early insults have been studied in different animal models supported by results from in vitro approaches leading to the successful application of some findings to the clinical setting in the past. Nonetheless, existing information about long-term consequences of the identified early and most likely sustained changes to the developing lung is limited. Interesting results point towards a tremendous impact of these early injuries on the pulmonary repair capacity as well as aging related processes in the adult lung.

Fifty years in neonatology

Neonatology, the care and study of newborn infants, is a 'young' specialty. Over the last 50 years, there have been many advances in the way that neonatologists care for newborn infants, particularly those born preterm, leading to dramatic improvements in mortality. To illustrate these advances, we describe four eras in neonatology from the point of view of the junior hospital doctor.

Neurally adjusted ventilatory assist in preterm neonates with acute respiratory failure

BACKGROUND

Neurally adjusted ventilatory assist (NAVA) is a novel mode of ventilation that has been demonstrated to improve infant-ventilator interaction, compared to the conventional modes in retrospective and short-term studies.

OBJECTIVES

To prospectively evaluate the physiologic effects of NAVA in comparison with pressure-regulated volume control (PRVC) in two nonrandomized 12-hour periods.

METHODS

We studied 14 consecutive intubated preterm neonates receiving mechanical ventilation for acute respiratory failure. Peak airway pressure (Pawpeak), diaphragm electrical activity (EAdi), tidal volume (VT), mechanical (RRmec) and neural (RRneu) respiratory rates, neural apneas, and the capillary arterialized blood gases were measured. The RRmec-to-RRneu ratio (MNR) and the asynchrony index were also calculated. The amount of fentanyl administered was recorded.

RESULTS

Pawpeak and VT were greater in PRVC (p < 0.01). Blood gases and RRmec were not different between modes, while RRneu and the EAdi swings were greater in NAVA (p = 0.02 and p < 0.001, respectively). MNR and the asynchrony index were remarkably lower in NAVA than in PRVC (p = 0.03 and p < 0.001, respectively). 1,841 neural apneas were observed during PRVC, with none in NAVA. Less fentanyl was administered during NAVA, as opposed to PRVC (p < 0.01).

CONCLUSIONS

In acutely ill preterm neonates, NAVA can be safely and efficiently applied for 12 consecutive hours. Compared to PRVC, NAVA is well tolerated with fewer sedatives.

Unraveling the Links Between the Initiation of Ventilation and Brain Injury in Preterm Infants

The initiation of ventilation in the delivery room is one of the most important but least controlled interventions a preterm infant will face. Tidal volumes (V T) used in the neonatal intensive care unit are carefully measured and adjusted. However, the V Ts that an infant receives during resuscitation are usually unmonitored and highly variable. Inappropriate V Ts delivered to preterm infants during respiratory support substantially increase the risk of injury and inflammation to the lungs and brain. These may cause cerebral blood flow instability and initiate a cerebral inflammatory cascade. The two pathways increase the risk of brain injury and potential life-long adverse neurodevelopmental outcomes. The employment of new technologies, including respiratory function monitors, can improve and guide the optimal delivery of V Ts and reduce confounders, such as leak. Better respiratory support in the delivery room has the potential to improve both respiratory and neurological outcomes in this vulnerable population.

Risk Indicators for Air Leaks in Preterm Infants Exposed to Restrictive Use of Endotracheal Intubation

OBJECTIVES

To identify perinatal risk indicators for air leaks in preterm infants treated with a policy of restrictive use of endotracheal intubation based on sustained inflations followed by noninvasive ventilation in the delivery room.

METHODS

Perinatal variables and variables of respiratory support in the delivery room were analyzed retrospectively in a cohort of 297 inborn preterm infants with a gestational age <29 weeks born in 2005-2009 in a tertiary care center with respect to their associations with air leaks. Multivariate logistic regression analysis was performed to analyze independent risk indicators.

RESULTS

Gestational age was 26 weeks + 0 days (22+3 to 28+6), birth weight was 790 g (265-1,660) and 270/297 survived (91.0%). A total of 63 (21.2%) developed air leaks, 32 (10.8%) pneumothorax, 44 (14.8%) pulmonary interstitial emphysema, and 1 (0.3%) pneumopericardium. The infants with air leaks had a higher risk of death (p < 0.01) and of intraventricular hemorrhage grade 3/4 (p < 0.05). Air leaks were associated with less use of prenatal steroids (p < 0.01), more frequent use of cardiac compressions (p < 0.01), use of a pressure of 30 cm H2O for sustained inflations (p < 0.05), and intubation in the delivery room (p < 0.01). After multivariate logistic regression only prenatal steroids (OR 0.41, 0.20-0.85), epinephrine (OR 3.56, 1.55-8.15) and surfactant use (OR 12.03, 3.39-42.72) remained significant.

CONCLUSIONS

Our approach resulted in a high survival rate but was associated with a substantial rate of air leaks, which were associated with death and severe intraventricular hemorrhage. Prenatal steroids were protective, and epinephrine and surfactant use were significant risk indicators, whereas the use of sustained inflations was not a risk factor.

An innovative nonanimal simulation trainer for chest tube insertion in neonates

BACKGROUND AND OBJECTIVE

Competence in the chest tube insertion procedure is vital for practitioners who take care of critically ill infants. The use of animals for training is discouraged, and there are no realistic simulation models available for the neonatal chest tube insertion procedure. The objective of this study was to assess the effectiveness of teaching the chest tube insertion procedure by using an easily constructed, nonanimal simulation model.

METHODS

An inexpensive infant chest tube insertion model was developed by using simple hardware. A prospective cohort study with pre-posttest intervention design was conducted with pediatric and combined internal medicine-pediatrics residents. Residents completed a questionnaire about their previous experience of chest tube insertion, knowledge, self-evaluation of knowledge, comfort, and skills; pre, post, and a month after an individualized education session and demonstration of the procedure on the model. Clinical skills were assessed by using a 32-point scoring system when residents performed the procedure on the model immediately after training and a month later.

RESULTS

All residents had significant improvement in knowledge and self-evaluation of knowledge, comfort, and skills scores after the education session and training on the model and this improvement was retained after 1 month (P < .001). Clinical skills scores decreased slightly 1 month after training (P = .08). Scores were not significantly different between the levels of trainees.

CONCLUSIONS

An educational intervention using an easily constructed and inexpensive chest tube insertion model is effective in improving knowledge, comfort, and skills in trainees. The model can be used repeatedly to maintain proficiency.

Cell-based therapies for the preterm infant

The severely preterm infant receives a multitude of life-saving interventions, many of which carry risks of serious side effects. Cell therapy is an important and promising arm of regenerative medicine that may address a number of these problems. Most forms of cellular therapy use stem/progenitor cells or stem-like cells, which have the capacity to migrate, engraft and exert anti-inflammatory effects. Although some of these cell-based therapies have made their way to clinical trials in adults, little headway has been made in the neonatal patient group. This review discusses the efficacy of cell therapy in preclinical studies to date and their potential applications to diseases that afflict many prematurely born infants. Specifically, we identify the major hurdles that must be overcome before cell therapies can be safely used in the neonatal intensive care unit.