Bronchopulmonary dysplasia. Survival after prolonged mechanical ventilation

Liberation and mortality outcomes in pediatric long-term ventilation: A qualitative systematic review

OBJECTIVE

To provide a systematic review of liberation from positive pressure ventilation and mortality of children with chronic respiratory failure who used long-term invasive and noninvasive ventilation (LTV).

METHODS

Papers published from 1980 to 2018 were identified using Pubmed MEDLINE, Ovid MEDLINE, Embase, and Cochrane databases. Search results were limited to English-language papers with (a) patients less than 22 years at initiation, (b) patients who used invasive ventilation (IV) via tracheostomy or noninvasive ventilation (NIV), and (c) data on mortality or liberation from LTV. Data were presented using descriptive statistics; changes in outcomes over time were explored using linear regression. Follow-up variability, cohort heterogeneity, and insufficient data precluded combining data to estimate incidences or rates.

RESULTS

One hundred and thirty papers with 12 704 patients were included. The median number of patients was 37 (interquartile range [IQR] 17-74, range 6-3802). Twenty-five percent of patients were initiated on IV; 75% on NIV. The maximum follow-up ranged from 0.5 to 31.8 years (median 8.8 years). The median proportion of patients liberated in these papers was 3% (IQR 0%-21%). The median proportion of mortality was 18% (IQR 8%-27%). Proportions of liberation and mortality did not significantly change over time. Progression of underlying disease (44%), respiratory illness (19%), and LTV accident (11%) were the most common causes of death.

CONCLUSIONS

These papers collectively show most patients survive for many years using LTV; in many subgroups, death is a more common outcome than liberation. However, the limitations of these papers preclude robust prognostication.

Allogeneic administration of human umbilical cord-derived mesenchymal stem/stromal cells for bronchopulmonary dysplasia: preliminary outcomes in four Vietnamese infants

Background

Bronchopulmonary dysplasia (BPD) is a severe condition in premature infants that compromises lung function and necessitates oxygen support. Despite major improvements in perinatal care minimizing the devastating effects, BPD remains the most frequent complication of extreme preterm birth. Our study reports the safety of the allogeneic administration of umbilical cord-derived mesenchymal stem/stromal cells (allo-UC-MSCs) and the progression of lung development in four infants with established BPD.

Methods

UC tissue was collected from a healthy donor, followed by propagation at the Stem Cell Core Facility at Vinmec Research Institute of Stem Cell and Gene Technology. UC-MSC culture was conducted under xeno- and serum-free conditions. Four patients with established BPD were enrolled in this study between May 25, 2018, and December 31, 2018. All four patients received two intravenous doses of allo-UC-MSCs (1 million cells/kg patient body weight (PBW) per dose) with an intervening interval of 7 days. Safety and patient conditions were evaluated during hospitalization and at 7 days and 1, 6 and 12 months postdischarge.

Results

No intervention-associated severe adverse events or prespecified adverse events were observed in the four patients throughout the study period. At the time of this report, all patients had recovered from BPD and were weaned off of oxygen support. Chest X-rays and CT scans confirmed the progressive reductions in fibrosis.

Conclusions

Allo-UC-MSC administration is safe in preterm infants with established BPD.

Trial registration This preliminary study was approved by the Vinmec International Hospital Ethics Board (approval number: 88/2019/QĐ-VMEC; retrospectively registered March 12, 2019).

Expensive care? Resource-based thresholds for potentially inappropriate treatment in intensive care

In intensive care, disputes sometimes arise when patients or surrogates strongly desire treatment, yet health professionals regard it as potentially inappropriate. While professional guidelines confirm that physicians are not always obliged to provide requested treatment, determining when treatment would be inappropriate is extremely challenging. One potential reason for refusing to provide a desired and potentially beneficial treatment is because (within the setting of limited resources) this would harm other patients. Elsewhere in public health systems, cost effectiveness analysis is sometimes used to decide between different priorities for funding. In this paper, we explore whether cost-effectiveness could be used to determine the appropriateness of providing intensive care. We explore a set of treatment thresholds: the probability threshold (a minimum probability of survival for providing treatment), the cost threshold (a maximum cost of treatment), the duration threshold (the maximum duration of intensive care), and the quality threshold (a minimum quality of life). One common objection to cost-effectiveness analysis is that it might lead to rationing of life-saving treatment. The analysis in this paper might be used to inform debate about the implications of applying cost-effectiveness thresholds to clinical decisions around potentially inappropriate treatment.

Rationing potentially inappropriate treatment in newborn intensive care in developed countries

In newborn intensive care, parents sometimes request treatment that professionals regard as 'futile' or 'potentially inappropriate'. One reason not to provide potentially inappropriate treatment is because it would be excessively costly relative to its benefit. Some public health systems around the world assess the cost-effectiveness of treatments and selectively fund those treatments that fall within a set threshold. This article explores the application of such thresholds to questions in newborn intensive care: (i) when a newborn infant's chance of survival is too small; (ii) how long treatment should continue; (iii) when quality of life is too low; and (iv) when newborn infants are too premature for cost-effective intensive care. This analysis yields some potentially surprising conclusions. Newborn intensive care may be cost-effective even in the setting of very low probability of survival, very poor predicted quality of life, for protracted periods of time, or for the most premature of newborns.

Neurally adjusted ventilatory assist for infants under prolonged ventilation

BACKGROUND

Severe bronchopulmonary dysplasia often leads to prolonged mechanical ventilation lasting several months. Cyanotic episodes frequently occur in these patients, necessitating long-term sedation and/or intermittent muscle paralysis. Neurally adjusted ventilatory assist (NAVA) might provide precisely the amount of support that these patients need without sedation.

METHODS

We reviewed the medical records of preterm infants who underwent tracheostomy and required mechanical ventilation for >6 months during a period of 6 years. We compared two groups of patients: those supported with NAVA for ≥2 months versus those supported by pneumatically triggered assist methods. We also evaluated any change after NAVA use in the NAVA group.

RESULTS

Among 14 prematurely born patients who received prolonged ventilation, nine were supported with NAVA and five were supported using other ventilator modes. Duration of continuous sedation was significantly shorter and the bolus use of sedatives was also significantly lower in the NAVA group than in the pneumatically triggered assist group. In addition, the NAVA group received a lower dose of dexamethasone than the pneumatically triggered assist group. Compared with before NAVA, the frequency of cyanotic episodes and of the bolus sedatives was significantly decreased after implementation of NAVA.

CONCLUSIONS

For infants on prolonged mechanical ventilation, NAVA could reduce cyanotic episodes and the need for sedatives and dexamethasone. NAVA may be superior to pneumatically triggered modes in terms of the minimization of patient-ventilator dyssynchrony while delivering appropriate respiratory support in premature infants with tracheostomy.

Determinants of chronic lung disease severity in the first year of life; A population based study

OBJECTIVES

First, create a clinical severity score for patients with chronic lung disease of infancy (CLDi) following neonatal intensive care unit (NICU) stay. Second, using California wide population-based data, identify factors associated with clinical severity of CLDi at 4-9 months corrected gestational age (CGA).

STUDY DESIGN

Pediatric pulmonologists ranked and weighted eight factors reflecting clinical severity of CLDi. Utilizing these data we scored and assigned these to 4-9 month old CGA moderate/severe bronchopulmonary dysplasia (BPD) infants, born<30 weeks gestational age (GA), within the California High Risk Infant Follow up (HRIF) program. Infants were studied relative to factors from the California Perinatal Quality Care Collaborative (CPQCC).

RESULTS

We received survey responses from 43/88 pediatric pulmonologists from 28/53 North American training centers who are experts in CLDi. Strong agreement between ranking (72-100%) of respiratory system parameters and weighting (out of 100 points weighting was within 20 points) was observed with severity of CLDi. Data from 940 CLDi premature infants <30 weeks GA were obtained. Infants with severe CLDi scores at 4-9 months CGA (relative to a zero score) showed positive associations with being male, odds ratio[OR] = 2.45[confidence interval (CI) 1.26-4.77]), >30 ventilator days, OR = 3.82 (1.30-11.2), postnatal steroids OR = 3.94 (1.94-7.84), and a surprising inverse association with retinopathy of prematurity stage 3-4, OR = 0.24 (0.09-0.67) CONCLUSIONS: The CLDi clinical severity score allowed for standardized assessment of pulmonary morbidity, and evaluation of risk factors in the NICU for CLDi following NICU discharge. These observations point to risk factors associated with CLDi outcomes at 4-9 months CGA.

Epidemiology of bronchopulmonary dysplasia

First described more than 40 years ago, bronchopulmonary dysplasia (BPD) remains one of the most serious and vexing challenges in the care of very preterm infants. Affecting approximately one-quarter of infants born <1500g birth weight, BPD is associated with prolonged neonatal intensive care unit hospitalization, greater risk of neonatal and post-neonatal mortality and a host of associated medical and neurodevelopmental sequelae. This seminar focuses on the epidemiology and definition of BPD as well as the current evidence pertaining to a number of potential preventive treatments for BPD: non-invasive respiratory support technologies, inhaled nitric oxide, vitamin A, and caffeine.

Intratracheal administration of glucocorticoids using surfactant as a vehicle

1. Glucocorticoids are an effective treatment in the amelioration of chronic lung disease in neonates. However, systemic administration of glucocorticoids to neonates is associated with significant side-effects that preclude them as an early intervention to prevent onset of the condition. Conversely, local intratracheal administration of glucocorticoids may prevent inflammatory insult to the lungs without the development of systemic side-effects. We therefore investigated whether local intratracheal delivery of corticosteroids could be facilitated using surfactant as a vehicle. 2. Addition of dexamethasone to either diluted or commercial artificial surfactant, Survanta (Abbott Industries, Sydney, NSW, Australia), did not alter the surface properties of the surfactant. 3. After intratracheal instillation to rats, radiolabelled dexamethasone in Survanta was well distributed throughout all four lobes of the lungs. A concentration gradient of the steroid was observed between the root and the peripheral sections of all lobes. 4. Our results suggest that surfactant is an effective vehicle for intratracheal delivery of glucocorticoids. Moreover, we propose that prophylactic intratracheal administration of glucocorticoids administered shortly after birth may prevent inflammatory insult to the lungs and thereby reduce the likelihood of chronic lung disease developing.

A three-day course of dexamethasone therapy to prevent chronic lung disease in ventilated neonates: a randomized trial

BACKGROUND

Although several trials of early dexamethasone therapy have been completed to determine if such therapy would reduce mortality and chronic lung disease (CLD) in infants with respiratory distress, optimal duration and side effects of such therapy remain unknown.

PURPOSE

The purpose of this study was: 1) to determine if a 3-day course of early dexamethasone therapy would reduce CLD and increase survival without CLD in neonates who received surfactant therapy for respiratory distress syndrome and 2) to determine adverse effects associated with such therapy.

DESIGN

This was a prospective multicenter randomized trial comparing a 3-day course of dexamethasone therapy beginning at 24 to 48 hours of life to placebo therapy. Two hundred forty-one neonates (dexamethasone n = 118, placebo n = 123), who weighed between 500 g and 1500 g, received surfactant therapy, and were at significant risk for CLD or death using a model to predict CLD or death at 24 hours of life, were enrolled in the trial. Infants randomized to receive early dexamethasone were given 6 doses of dexamethasone at 12-hour intervals beginning at 24 to 48 hours of life. The primary outcomes compared were survival without CLD and CLD. CLD was defined by the need for supplemental oxygen at the gestational age of 36 weeks. Complication rates and adverse effects of study drug therapy were also compared.

RESULTS

Neonates randomized to early dexamethasone treatment were more likely to survive without CLD (RR: 1.3; 95% CI: 1.03, 1.7) and were less likely to develop CLD (RR: 0.6; CI: 0.3, 0. 98). Mortality rates were not significantly different. Subsequent dexamethasone therapy use was less in early dexamethasone-treated neonates (RR: 0.8; CI: 0.7, 0.96). Very early (</=7 days of life) intestinal perforations were more common among dexamethasone-treated neonates (8% vs 1%).

CONCLUSION

We conclude that an early 3-day course of dexamethasone therapy increases survival without CLD, reduces CLD, and reduces late dexamethasone therapy in high-risk, low birth weight infants who receive surfactant therapy for respiratory distress syndrome. Potential benefits of early dexamethasone therapy at the dosing schedule used in this trial need to be weighed against the risk for early intestinal perforation.

Prolonged mechanical ventilation in children

Improvements in neonatal and pediatric intensive care have produced a growing population of children dependent on mechanical ventilation for survival. Long-term mechanical ventilation has become a realistic alternative to death from progressive respiratory failure for many children with chronic respiratory illness. This article reviews the pathophysiology, etiology, and management of chronic respiratory failure in childhood.

Prognostic value of clinical and radiological status on day 28 of life for subsequent course in very low birthweight (< 1,500g) babies with bronchopulmonary dysplasia

To test the hypothesis that the short-term (approximately 6 months) course of babies with bronchopulmonary dysplasia (BPD) could be predicted from the clinical and radiological status on day 28 of life, we retrospectively examined the medical records of 79 infants born between 1985 and 1988 who required supplemental oxygen and/or ventilatory support on day 28. Chest roentgenographs taken close to day 28 (+/- 7 days) were scored on a scale of 0-10. Four babies died from causes not related to BPD. Four of the remaining 75 died from BPD, and the rest are alive. Forty-six of 71 were weaned from supplementary oxygen by 37 weeks corrected gestational age, and only 13/71 remained on supplemental oxygen after 40 weeks gestational age. To determine which variables contributed most to the outcome, defined as total days on supplemental oxygen, a multiple regression analysis was performed, including only those variables the tolerance of which exceeded 0.7 (sex, FiO2, ventilatory mode, and infectious status). FiO2 and ventilatory mode together predicted 15% of the variability in outcome, so that a high FiO2 and ventilator dependence on day 28 of life were highly correlated with a prolonged need for supplemental oxygen (F = 4.28, P < 0.05).

Prediction of outcome of preterm infants with severe bronchopulmonary dysplasia

Forty-four preterm infants of less than 30 weeks gestation and birthweight < or = 1250 g, with severe bronchopulmonary dysplasia requiring mechanical ventilation for at least 28 days, were reviewed. Twenty-seven infants (61%) survived; 17 died. There were no significant differences between survivors and non-survivors with respect to birthweight, gestational age, sex, Apgar score at 5 min or pulmonary diagnosis. Non-survivors displayed more severe changes on chest X-ray than the survivors. Peak inspiratory pressure (PIP), ventilator rate (VR), ventilator index and mean airways pressure were significantly higher in the non-surviving infants on days 2, 3, 4, 7, 14, 21 and 28, with non-survivors also having significantly higher alveolar-arterial oxygen gradients and lower arterial-alveolar oxygen ratios than the survivors. Discriminant analysis with cross-validation by pairing PIP and VR on day 28 produced a positive predictive value for non-survival of 88% and a negative predictive value of 89%. This result was better than was obtained for any other pair of ventilator parameter or oxygenation index. Discriminant analysis by combining X-ray appearances with ventilator settings did not improve the prediction. Having established a statistical model based on the PIP and VR of ventilator-dependent preterm infants on day 28, the outcome can be predicted with a high degree of confidence. This has the immediate potential application of indicating to staff in the neonatal unit a realistic approach to take when counselling parents of these infants.

First-year infections after initial hospitalization in low birth weight infants with and without bronchopulmonary dysplasia

Symptoms of infection, specific infections, antibiotic course and hospitalizations were evaluated prospectively by using monthly questionnaires after initial hospitalization in 73 low birth weight (LBW) infants (less than 1751 g) and a subgroup of 19 infants with bronchopulmonary dysplasia (BPD) compared with 63 full-term controls matched for age, sex and home locality. The immunoglobulin G, A, M and E levels of the LBW infants were measured at corrected ages of 1, 2, 4, 6, 8, 10 and 12 months. The LBW infants, the subgroup with BPD and their controls had similar frequencies of infectious symptoms and episodes of infection. Dyspnoea and lower respiratory tract infections often caused by respiratory syncytial virus (RBV) were more frequent and more severe among LBW and especially BPD infants compared with controls. Male sex, a large family and day-care were significant risk factors for illness. The IgG levels of the LBW infants were subnormal at the corrected age of 1 month, but otherwise immunoglobulin levels were normal. The results suggest that LBW infants and especially those with BPD are prone to lower respiratory tract infections and should be considered candidates for immunoprophylaxis against RBV. In order to reduce morbidity home care is preferable to day-care.

The effect of extracorporeal membrane oxygenation on the survival of neonates with high-risk congenital diaphragmatic hernia: 45 cases from a single institution

At The Children's Hospital, Boston (TCH), in the 3 years before extracorporeal membrane oxygenation (ECMO) was available, infants with high-risk congenital diaphragmatic hernia (CDH) had a 47% survival rate. In February 1984, ECMO was introduced and offered to all high-risk CDH infants with a 100% predicted mortality. Since February 1984, 45 infants with high-risk CDH presented to TCH. Twenty-six (58%) were supported with ECMO; 19 (42%) never met the criteria for 100% predicted mortality and were supported with conventional mechanical ventilation (CMV). Overall survival was 49%. Nine (35%) of the 26 ECMO patients survived. Thirteen (68%) of the 19 CMV patients survived. Although there was no change in survival, there was a change in the cause of death. Deaths in the ECMO group were either early (n = 8, secondary to a complication of ECMO or lack of pulmonary improvement) or late (n = 9). The late deaths were infants who were successfully weaned from ECMO, never weaned from CMV, and who died secondary to complications of chronic lung disease.

Bronchopulmonary dysplasia. Pharmacologic treatments and prediction of outcome

Bronchopulmonary dysplasia (BPD) is a progressive disorder of the lungs of newborn infants initially involving distal airways, but followed in weeks by the development of abnormalities in all parts of the lung architecture. BPD develops primarily but not exclusively in premature infants. The incidence in the general population has never been assessed accurately in a prospective manner. One retrospectively calculated incidence figure is 1.2 infants per 1,000 total live births per year in the United States (17). With approximately 4 million births annually in North America, there are about 5,000 babies each year who develop BPD. The additional weeks, months, and, in some cases, years of hospitalization, the frequent rehospitalizations, and the mortality of 20–50% beyond 1 month of age (17) underscore the disproportionate financial and emotional toll of BPD not only on patients and families but caregivers as well. The glacial rates of improvement in the illness, the frequent setbacks, and the profound disruption to family life all support the contention that BPD is a major public health problem.