Trends in caffeine use and association between clinical outcomes and timing of therapy in very low birth weight infants

Impact of early caffeine administration on respiratory outcomes in very preterm infants initially receiving invasive mechanical ventilation

OBJECTIVE

The guidelines recommend early caffeine administration for preterm infants requiring non-invasive mechanical ventilation since earlier treatment is associated with better outcomes. The objective was to evaluate the impact of early caffeine therapy (within 24 hours after birth) on respiratory outcomes in very preterm infants who were initially receiving invasive mechanical ventilation.

METHODS

This was an observation cohort study from 1 January 2018 to 31 December 2022 based on a database that was prospectively collected and maintained. Infants who initially received invasive mechanical ventilation were divided into two groups based on the timing of caffeine initiation: within the first 24 hours after birth (early) and within 48 hours of birth or later (late). Generalised linear mixed models with a random effect model for the centre were used to assess the impact of different caffeine initiation times on neonatal outcomes.

RESULTS

Among the cohort of 9880 infants born at <32 weeks gestation, 2381 were eligible for this study (early initiation: 1758 (73.8%) and late initiation: 623 (26.2%)). For infants born at more than 28 weeks of gestation, the adjusted generalised linear mixed model showed that the duration of invasive mechanical ventilation was 1.34 (95% CI -2.40 to -0.27) days shorter and the incidence of moderate-to-severe bronchopulmonary dysplasia (BPD) was lower (adjusted OR 0.63; 95% CI 0.41 to 0.96) in the early caffeine group compared with the late caffeine group.

CONCLUSION

In very preterm infants who initially receive invasive mechanical ventilation, early administration of caffeine within 24 hours after birth can shorten the duration of invasive mechanical ventilation, reduce the incidence of moderate-to-severe BPD and improve respiratory outcomes. The very early initiation of caffeine treatment does not appear to be associated with any adverse outcomes.

TRIAL REGISTRATION NUMBER

ChiCTR1900025234.

Strategies for the prevention of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a common morbidity affecting preterm infants and is associated with substantial long-term disabilities. The pathogenesis of BPD is multifactorial, and the clinical phenotype is variable. Extensive research has improved the current understanding of the factors contributing to BPD pathogenesis. However, effectively preventing and managing BPD remains a challenge. This review aims to provide an overview of the current evidence regarding the prevention of BPD in preterm infants, offering practical insights for clinicians.

Administration time of caffeine in preterm infants: systematic review and meta-analysis

To assess the ideal time for caffeine administration in preterms, identifying its effects and safety. Study Design: Meta-analysis conducted including preterms <32 weeks GA or BW < 1500 g, comparing caffeine administration time: <24 x ≥24HOL, <48 x ≥48HOL, <72 x ≥72HOL. 18 studies included 76.998 patients. The median age of starting caffeine was the first 24 HOL. In the overall comparisons, there was reduction in patent ductus arteriosus (OR 0.71 [0.55, 0. 92]; low evidence), retinopathy of prematurity (OR 0.71 [0.54, 0.93]; moderate evidence), severe brain injury (OR 0.79 [0.70, 0.91]; moderate evidence), bronchopulmonary dysplasia (BPD) (OR 0.69 [0.59, 0.81]; moderate evidence), composite outcome of BPD or death (OR 0.76 [0.66, 0.88]; moderate evidence). Mortality increase was found (OR 1.20 [1.12, 1.29], very low evidence).Caffeine in the first 24 HOL has benefits in reducing morbidities associated with prematurity. Mortality finding is potentially due to survival bias.

Evaluation of a respiratory care protocol including less invasive surfactant administration in preterm infants

BACKGROUND

Respiratory care protocol including less invasive śsurfactant administration (LISA) in ≤29 weeks' gestational age (GA) infants introduced in October 2018.

METHODS

Retrospective study of infants admitted on continuous positive airway pressure (CPAP) October 2018 to December 2021. Maternal and neonatal variables were compared between infants managed on CPAP with and without LISA. Infants who received LISA and subsequently required mechanical ventilation (MV) within 72 h of life (HOL) [LISA failure (LF)] were compared with those who required no MV [LISA success (LS)].

RESULTS

249 infants were admitted on CPAP, 5 were intubated prior to LISA, 143 required LISA and 101 remained on CPAP without surfactant. Of those receiving LISA, 108 were LS and 35 were LF. Compared to LS, LF infants were of lower GA and birth weight, required higher fractional inspired oxygen (FiO2), and CPAP level at birth, admission, one HOL, and an hour after LISA. Moreover, LF infants had higher mortality and morbidity. Together GA ≤ 25 weeks' and FiO2 ≥ 0.3 an hour after LISA best predicted LF.

CONCLUSIONS

Over 80% of infants admitted on CPAP avoided MV within 72 HOL. Early predictors of LF provide targets for future interventions to decrease need for MV in preterm infants.

IMPACT

Less invasive surfactant administration (LISA) decreases the need for mechanical ventilation (MV) and improves outcomes. However, some infants require MV within 72 h of life (HOL) despite LISA (LISA failure). Over 80% of ≤29 weeks' gestational age (GA) infants can be successfully managed on CPAP with or without surfactant in the first 72 HOL. A combination of factors including ≤25 weeks' GA and fraction of inspired oxygen ≥0.3 an hour after LISA predict LISA failure. Evaluation of a noninvasive respiratory support strategy including LISA provides targets for intervention to decrease need for MV in preterm infants.

The Babyccino: The Role of Caffeine in the Prevention of Acute Kidney Injury in Neonates-A Literature Review

Acute kidney injury (AKI) in neonates is associated with increased morbidity and mortality. Theophylline (a methylxanthine) has been shown to prevent neonatal AKI but is seldom used due to its unfavorable profile. Caffeine, another methylxanthine, is utilized ubiquitously to treat apnea of prematurity, but there are no randomized trials evaluating its efficacy in preventing neonatal AKI. This literature review aims to summarize the existing research pertaining to the relationship between caffeine and neonatal AKI. The review was conducted using Pubmed, Embase, Google Scholar, and Cochrane. Inclusion criteria incorporated empirical studies, being published in English, and being available electronically. All eight studies identified were included. Seven studies found caffeine-exposed premature neonates had lower rates of AKI than caffeine-unexposed neonates. Four found reduced AKI severity with caffeine exposure. One study included term neonates and did not find a difference in the AKI rate between caffeine-exposed and non-exposed babies. Limitations include exclusively observational studies, short study periods, heterogenous definitions of prematurity, and a lack of assessment of dose-effect relationships. In conclusion, premature neonates exposed to caffeine appear to have lower rates and potentially less severe AKI. Further research is needed before caffeine can be considered for use in the primary prevention of neonatal AKI.

Caffeine and kidney function at two years in former extremely low gestational age neonates

BACKGROUND

Extremely low gestational age neonates (ELGANs) are at risk for chronic kidney disease. The long-term kidney effects of neonatal caffeine are unknown. We hypothesize that prolonged caffeine exposure will improve kidney function at 22-26 months.

METHODS

Secondary analysis of the Preterm Erythropoietin Neuroprotection Trial of neonates <28 weeks' gestation. Participants included if any kidney outcomes were collected at 22-26 months corrected age. Exposure was post-menstrual age of caffeine discontinuation.

PRIMARY OUTCOMES

'reduced eGFR' <90 ml/min/1.73 m2, 'albuminuria' (>30 mg albumin/g creatinine), or 'elevated blood pressure' (BP) >95th %tile. A general estimating equation logistic regression model stratified by bronchopulmonary dysplasia (BPD) status was used.

RESULTS

598 participants had at least one kidney metric at follow up. Within the whole cohort, postmenstrual age of caffeine discontinuation was not associated with any abnormal measures of kidney function at 2 years. In the stratified analysis, for each additional week of caffeine, the no BPD group had a 21% decreased adjusted odds of eGFR <90 ml/min/1.73m2 (aOR 0.78; CI 0.62-0.99) and the BPD group had a 15% increased adjusted odds of elevated BP (aOR 1.15; CI: 1.05-1.25).

CONCLUSIONS

Longer caffeine exposure during the neonatal period is associated with differential kidney outcomes at 22-26 months dependent on BPD status.

IMPACT

In participants born <28 weeks' gestation, discontinuation of caffeine at a later post menstrual age was not associated with abnormal kidney outcomes at 22-26 months corrected age. When assessed at 2 years of age, later discontinuation of caffeine in children born <28 weeks' gestation was associated with a greater risk of reduced eGFR in those without a history of BPD and an increased odds of hypertension in those with a history of BPD. More work is necessary to understand the long-term impact of caffeine on the developing kidney.

Association of Caffeine Daily Dose With Respiratory Outcomes in Preterm Neonates: A Retrospective Cohort Study

Apnea and poor respiratory drive increase the risk of extubation failure (EF) and prolonged invasive mechanical ventilation (IMV) in preterm neonates (pre-nates) with respiratory distress. Caffeine citrate (CC) is often prescribed for pre-nates in doses of 5-10 mg/kg in 24 h. This study aimed to evaluate the most effective dosage regimen (5 mg/kg/day vs >5-10 mg/kg/day) to prevent apnea and EF with minimal caffeine-associated potential side effects (CC-APSEs) in pre-nates. This one-year retrospective cohort study included all the eligible neonates admitted to NICU and received CC-therapy till 28 days of life (DOL) or discharge. Based on CC-daily dose formed LD-caffeine-group (5 mg/kg/day) and HD-caffeine-group (>5-10 mg/kg/day). Antenatal, prenatal, and postnatal characteristics, CC-regimen, comorbidities, and CC-APSEs were compared between the groups. Predictors of apnea and EF were analyzed through logistic regression. There were 181 and 72 neonates in the LD and HD-caffeine-groups respectively. In HD-caffeine-group daily CC-dose was 7 to 7.5 mg/kg/day in 93% of neonates and >7.5 to 10 mg/kg/day in only 7%. Significantly fewer neonates experienced apnea and EF in the HD-caffeine-group till 28DOL or discharge. This difference was even greater in the subgroup of ≤28 weeks GA (15.6% vs 40.0%; P < .01). In HD-caffeine-group the incidence of severe/moderate-BPD was significantly lower and the frequency of CC-APSEs was higher. Multivariate analysis showed that; the smaller the GA higher the risk of apnea (AOR = 0.510, 95% CI 0.483-0.999) and EF (AOR = 0.787, 95% CI 0.411-0.997). The HD-caffeine was inversely associated with developing apnea (AOR = 0.244, 95% CI 0.053-0.291) and EF (AOR = 0.103, 95% CI 0.098-2.976). IMV-duration before extubation (AOR = 2.229, 95% CI 1.672-2.498) and severe/moderate-BPD (AOR = 2.410, 95%CI 1.104-2.952) had a high risk of EF. Initiating early HD-caffeine may prevent apnea and extubation failure in preterm neonates. Optimization of caffeine initiation time and dosages can be a safe and feasible approach to decrease the burden of neonatal respiratory morbidities.

National survey on caffeine use in neonatal units across the United Kingdom

AIM

To understand the variations in practice for caffeine use among neonatal units in the United Kingdom.

METHODS

An online survey was sent to every neonatal unit in the United Kingdom.

RESULTS

We received a response from 92 neonatal units (47%) with the proportion of response from special care, Local neonatal units, neonatal intensive care units and neonatal surgical units were 23%, 34%, 23% and 21% respectively. All the units reported the use of caffeine, and 40 units (46%) initiated caffeine within 24 h of birth. Fifty-nine units (64%) reported routine use of caffeine for pre-term infants <32 weeks. Seventy-one units (77%) reported that they continue caffeine for infants needing mechanical ventilation. Thirty-one units (34%) discontinued caffeine at 34 weeks post-menstrual age, irrespective of the respiratory support. Ten units (11%) reported discontinuation of caffeine only after weaning off all respiratory support, and 40% of units had a variable practice of discontinuing caffeine depending on the individual baby. Seventy-nine units (86%) reported they would regularly optimise caffeine dose based on weight checks.

CONCLUSION

Our survey showed some variation in practice with regards to the timing of caffeine initiation, gestational age cut-off for routine caffeine prescription and discontinuation.

Observational cohort study of use of caffeine in preterm infants and association between early caffeine use and neonatal outcomes

OBJECTIVE

To quantify trends in caffeine use in infants born at <32 weeks' gestational age (GA), and to investigate the effects of early vs late caffeine on neonatal outcomes.

STUDY DESIGN

Retrospective propensity score matched cohort study using routinely recorded data from the National Neonatal Research Database of infants born at <32 weeks' GA admitted to neonatal units in England and Wales (2012-2020).

RESULTS

89% (58 913/66 081) of infants received caffeine. In 70%, caffeine was started early (on the day of birth or the day after), increasing from 55% in 2012 to 83% in 2020. Caffeine was given for a median (IQR) of 28 (17-43) days starting on day 2 (1-3) and continued up to 34 (33-34) weeks postmenstrual age.In the propensity score matched cohort of 13 045 pairs of infants, the odds of preterm brain injury (early caffeine, 2306/13 045 (17.7%) vs late caffeine, 2528/13 045 (19.4%), OR=0.89 (95% CI 0.84 to 0.95)) and bronchopulmonary dysplasia (BPD) (early caffeine, 4020/13 045 (32.8%) vs late caffeine, 4694/13 045 (37.7%), OR=0.81 (95% CI 0.76 to 0.85)) were lower in the group that received early caffeine compared with those who received it later.

CONCLUSIONS

Early use of caffeine has increased in England and Wales. This is associated with reduced risks of BPD and preterm brain injury. Randomised trials are needed to find the optimal timing of caffeine use and the groups of infants who will benefit most from early administration of caffeine.

A Modern Look at the Development of Intrauterine Pneumonia in Premature Newborns: Literature Review

Infectious diseases such as malaria, pneumonia, diarrhea and preventable neonatal diseases are common causes of death in children. Globally, neonatal mortality is 44% (2.9 million) annually, with up to 50% of babies dying within the first day of life. Pneumonia kills between 750000 and 1.2 million infants in the neonatal period each year in developing countries. Premature birth, pneumonia, and labor complications are common causes of neonatal mortality. The objective of the study is to present the general characteristics of congenital pneumonia, vitamin D deficiency and micronutrient deficiencies in premature infants. To date, numerous studies confirm the relationship between the inadequate supply of the body with macro- and microelements and the development of diseases of varying severity, including metabolic disorders. Based on this, primary screening, aimed at identifying metabolic disorders of macro- and microelements and further drug correction, should become the main concept for the management of patients in modern times.

Effects of caffeine on diaphragmatic activity in preterm infants

BACKGROUND

Caffeine is the first-choice drug for the treatment for apnea of prematurity (AOP) in preterm infants and it has been reported that it improves the diaphragm activity. The aim of this study was to evaluate by ultrasound possible changes in diaphragm contractility and motility induced by caffeine.

METHODS

We studied 26 preterm infants with gestational age ≤34 weeks treated with caffeine for the prevention or treatment of AOP. Diaphragmatic ultrasound was performed 15 min (T₀ ) before and 60 min (T₆₀ ) after the loading (20 mg/kg) or maintenance (5 mg/kg) dose of caffeine.

RESULTS

Diaphragmatic excursion (DE) and thickness at the end of inspiration (DT-in) and expiration (DT-ex), as well as peak velocity of the excursion at the end of inspiration (DT-in) and expiration (DT-ex) increased after administration of both loading and maintenance dose of caffeine.

CONCLUSIONS

Ultrasounds confirmed that caffeine improves the activity of diaphragm in preterm infants improving its thickness, amplitude of excursions, and contraction velocity. These results are consistent with the effectiveness of caffeine in treating AOP and decreasing the risk of failure of noninvasive respiratory support in preterm infants with respiratory distress syndrome (RDS).

Effects of a small-baby protocol on early and long-term outcomes in extremely preterm infants: A quality improvement study

BACKGROUND

Extremely preterm (EPT) infants (≤28 weeks) remain at risk for poor outcomes. Small baby protocols (SBPs) may improve outcomes, but optimal strategies are unknown.

METHODS

This study evaluated whether EPT infants managed using an SBP would have better outcomes compared to a historical control (HC) group. The study compared a HC group of EPT infants 23 0/7 weeks to 28 0/7 weeks GA (2006-2007), to a similar SBP group (2007-2008). Survivors were followed until 13 years of life. The SBP emphasized antenatal steroids, delayed cord clamping, respiratory and hemodynamic minimalism, prophylactic indomethacin, early empiric caffeine, and control of sound and light.

RESULTS

There were 35 HC subjects and 35 SBP subjects. The SBP group had less severe IVH-PVH (9 % vs. 40 %, risk ratio 0.7, 95 % CI 0.5-0.9, P = 0.002) mortality (17 % vs. 46 %, risk ratio 0.6, 95 % CI 0.5-0.9, P = 0.004), and acute pulmonary hemorrhage (6 % vs. 23 %, risk ratio 0.8, 95 % CI 0.7-1.0, P = 0.04). Compliance with the SBP protocol was excellent. For the SBP group in the first 72 h, no subjects received inotropes, hydrocortisone, or sodium bicarbonate. Intubation, mechanical ventilation, fluid boluses, sedation, red blood cell transfusions, and insulin use decreased. At 10-13 years, more SBP subjects had survived without NDI (51 % vs. 23 %, risk ratio = 1.6, 95 % CI = 1.1-2.4, P = 0.01). More SBP subjects also survived without NDI and with a Vineland Adaptive Behavior Composite score > 85 (44 % vs. 11 %, risk ratio = 2.0, 95 % CI = 1.2-3.2, P ≤0.001). The SBP group had less visual impairment.

CONCLUSION

An SBP was associated with improved outcomes, including normal neurologic survival after 10 years.

Respiratory management in the premature neonate

INTRODUCTION

Advances in neonatal care have made possible the increased survival of extremely preterm infants. Even though there is widespread recognition of the harmful effects of mechanical ventilation on the developing lung, its use has become imperative in the management of micro-/nano-preemies. There is an increased emphasis on the use of less-invasive approaches such as minimally invasive surfactant therapy and non-invasive ventilation that have been proven to result in improved outcomes.

AREAS COVERED

Here, we review the evidence-based practices surrounding the respiratory management of extremely preterm infants including delivery room interventions, invasive and non-invasive ventilation approaches, and specific ventilator strategies in respiratory distress syndrome and bronchopulmonary dysplasia. Adjuvant relevant respiratory pharmacotherapies used in preterm neonates are also discussed.

EXPERT OPINION

Early use of non-invasive ventilation and use of less invasive surfactant administration are key strategies in the management of respiratory distress syndrome in preterm infants. Ventilator management in bronchopulmonary dysplasia must be tailored according to the individual phenotype. There is strong evidence to start caffeine early to improve respiratory outcomes, but evidence is lacking on the use of other pharmacological agents in preterm neonates, and an individualized approach has to be considered for their use.

Effects of Different Onset Times of Early Caffeine Treatment on Mesenteric Tissue Oxygenation and Necrotizing Enterocolitis: A Prospective, Randomized Study

OBJECTIVE

Caffeine treatment is routinely used in premature infants to prevent development of apnea and bronchopulmonary dysplasia. Although a limited number of studies have reported that early caffeine treatment may cause development of necrotizing enterocolitis (NEC) by reducing mesenteric blood flow, this issue is still under discussion. The aim of this study is to investigate the possible effect of different onset times of early caffeine treatment on mesenteric tissue oxygen saturation and NEC development in premature infants.

STUDY DESIGN

A total of 87 preterm infants with ≤1,250-g birth weight (BW) was included in this prospective study. The cases were randomized as group 1 (first 24 hours) and group 2 (72nd hour) caffeine treatment groups and monitored by near-infrared spectroscopy (NIRS) for 72 hours from the time of admission until cerebral, renal, and mesenteric tissue oxygen saturations (rSO₂) were recorded. The cases were followed-up to the 40th week in terms of NEC and other neonatal morbidities.

RESULTS

A total of 87 infants were included in the study, including 45 in group 1 and 42 in group 2. The groups were similar in terms of demographic characteristics. The incidence of NEC in group 1 (20%) was higher in comparison to group 2 (9%). The mesenteric rSO₂ values in the first 72 hours of group 1 were lower than those of group 2. Low gestational week, BW, and late onset of enteral feeding were found to be other significant risk factors for NEC.

CONCLUSION

In this study, mesenteric tissue oxygenation was lower, and NEC was higher in group 1. Mesenteric rSO₂ measurements may be useful in predicting the development of NEC in patients receiving early caffeine therapy.

KEY POINTS

· Onset time of early caffeine treatment may effect on mesenteric tissue oxygen saturation.. · Caffeine treatment that onset in the first 24 hours may be associated with NEC development.. · Mesenteric rSO2 measurements may be useful in patients receiving early caffeine therapy..

Effects of early aminophylline therapy on clinical outcomes in premature infants

BACKGROUND

Aminophylline use and the association between clinical outcomes and therapy timing have been less investigated. The objective of this study was to determine the efficacy of early aminophylline use (within the first two days of life) in premature infants.

METHOD

A retrospective observational cohort of infants weighing <1500 g and <30 weeks of gestational age at Kaohsiung Veterans General Hospital received aminophylline either within the first two days of life (EA, early aminophylline group), after the third day of life (LA, late aminophylline group), or without aminophylline during the first month of life (WA, without aminophylline group). Demographic data and neonatal clinical outcomes were compared among the three groups.

RESULTS

This study included 89 preterm infants (EA = 33, LA = 38, WA = 18). The EA group had a lower incidence of bronchopulmonary dysplasia (BPD) than the WA group (adjusted odds ratio [aOR] = 8.86(1.56-59.32); P = 0.024). Although there was no significant difference in BPD incidence between the EA and LA groups (aOR = 2.66(0.51-13.81), P = 0.244), a trend remained. Birth body weight less than 1000 g was also a significant risk factor for BPD (aOR = 8.86(1.32-47.41), P = 0.014). The duration of mechanical ventilation was shorter in the infants in the EA group compared to the WA group (estimated beta = -11.344(-19.57-3.12); P = 0.008).

CONCLUSION

Early aminophylline administration may be associated with a decreased incidence of BPD in preterm infants. However, the clinical benefits of aminophylline treatment require further investigation. In addition, a birth body weight of less than 1000 g was a crucial risk factor for BPD.

Therapeutic Interventions in Rat Models of Preterm Hypoxic Ischemic Injury: Effects of Hypothermia, Caffeine, and the Influence of Sex

Infants born prematurely have an increased risk of experiencing brain injury, specifically injury caused by Hypoxia Ischemia (HI). There is no approved treatment for preterm infants, in contrast to term infants that experience Hypoxic Ischemic Encephalopathy (HIE) and can be treated with hypothermia. Given this increased risk and lack of approved treatment, it is imperative to explore and model potential treatments in animal models of preterm injury. Hypothermia is one potential treatment, though cooling to current clinical standards has been found to be detrimental for preterm infants. However, mild hypothermia may prove useful. Caffeine is another treatment that is already used in preterm infants to treat apnea of prematurity, and has shown neuroprotective effects. Both of these treatments show sex differences in behavioral outcomes and neuroprotective effects, which are critical to explore when working to translate from animal to human. The effects and research history of hypothermia, caffeine and how sex affects these treatment outcomes will be explored further in this review article.

A survey of barriers and facilitators to caffeine use for apnoea of prematurity in low- and middle-income countries

BACKGROUND

Despite its associated benefits which include better long-term pulmonary and neurodevelopmental outcome, the use of caffeine for apnoea of prematurity (AoP) has been limited in low- and middle-income countries (LMIC).

AIM

To better understand current caffeine use, the barriers and facilitators to its use and perceptions and practices in LMIC which have a disproportionately high burden of prematurity.

METHODS

An anonymous online global survey was conducted, targeting healthcare providers working and training in paediatrics and/or neonatology in LMIC.

RESULTS

A total of 181 respondents in 16 LMIC were included in the analysis; most were physicians working in publicly-funded urban tertiary hospitals. Most had received training in the use of caffeine for AoP (77%), reported expertise (70%) and confidence (96%) in its use, and had access to caffeine (65%). Caffeine availability was reported to be the greatest barrier (48%) and the greatest facilitator (37%). Other common barriers included cost (31%), access (7%) and policies or guidelines on caffeine use (7%); other common facilitators included policies or guidelines on caffeine use (11%), access (10%), staff/other providers' acceptance of caffeine as an appropriate treatment (9%) and the availability of staff to administer caffeine (8%). Most (79%) noted that access to caffeine was important, 92% agreed that caffeine improves quality of care, and 95% agreed that caffeine improves patient outcome.

CONCLUSION

Improving availability and access to low-cost caffeine will be key to increasing caffeine use in LMIC.

ABBREVIATIONS

AoP: Apnoea of Prematurity; LMIC: low- and middle-Income countries; REDCap: Research Electronic Data Capture.

Caffeine and bronchopulmonary dysplasia: Clinical benefits and the mechanisms involved

Bronchopulmonary dysplasia (BPD) is a chronic respiratory disease that occurs during the neonatal period and is commonly associated with prematurity. This condition results in a severe economic burden on society and the families involved. Caffeine is used not only for the treatment of apnea in prematurity, but also for the prevention of BPD. There are multiple clinical benefits of caffeine treatment, including improved extubation success, a reduced duration of mechanical ventilation, improved lung function, and a reduction of patent ductus arteriosus requiring treatment. These clinical benefits of caffeine for the treatment of BPD are supported by both clinical trials and evidence from animal models. However, the mechanism by which caffeine protects against BPD remains unclear. Here, we review the clinical value of caffeine in the prevention of BPD and its potential mechanisms of action, including anti-inflammatory, antioxidant, antifibrotic, and antiapoptotic properties, the regulation of angiogenesis, and diuretic effects. Our aim is to provide a new theoretical basis for the clinical treatment of BPD.

Moving Bronchopulmonary Dysplasia Research from the Bedside to the Bench

Although advances in the respiratory management of extremely preterm infants have led to improvements in survival, this progress has not yet extended to a reduction in the incidence of bronchopulmonary dysplasia (BPD). BPD is a complex multifactorial condition that primarily occurs due to disturbances in the regulation of normal pulmonary airspace and vascular development. Preterm birth and exposure to invasive mechanical ventilation also compromises large airway development, leading to significant morbidity and mortality. Although both predisposing and protective genetic and environmental factors have been frequently described in the clinical literature, these findings have had limited impact on the development of effective therapeutic strategies. This gap is likely because the molecular pathways that underlie these observations are yet not fully understood, limiting the ability of researchers to identify novel treatments that can preserve normal lung development and/or enhance cellular repair mechanisms. In this review article, we will outline various well-established clinical observations whilst identifying key knowledge gaps that need to be filled with carefully designed pre-clinical experiments. We will address these issues by discussing controversial topics in the pathophysiology, the pathology and the treatment of BPD, including an evaluation of existing animal models that have been used to answer important questions.

The center-effect on outcomes for infants born at less than 25 weeks

Marked variation exists in the care of infants born at <25 weeks' gestation. The center or location where a fetus or infant is cared for influences outcomes at very early gestational ages. Understanding this "center-effect," including characteristics associated with centers that have high survival of births at <25 weeks' gestation, may inform future studies and guide care practices to improve outcomes. This review focuses on the impact that the location or center of birth has on survival and other important outcomes for infants born at <25 weeks' gestation. We review potential sources of variation in care practices and other factors that might explain the "center-effect."

Evidence of an active Cushing reflex in a preterm neonate with hyaline membrane disease: a case report

Background

The Cushing reflex does not appear to have been described in preterm neonates. This case report shows the presence of an active Cushing reflex in a 32-week preterm neonate with hyaline membrane disease.

Case presentation

The 1.94 kg Caucasian infant was delivered by caesarean section following concerns about possible maternal infection and fetal compromise. Chest X-ray showed mild-to-moderate hyaline membrane disease and treatment was initiated with supplemental oxygen and nasal continuous positive airway pressure. It is probable that a pneumothorax occurred at 5–6 hours of age, with progression during the day. Interstitial air, pneumomediastinum, and tension pneumothorax were diagnosed on subsequent X-ray, and ultrasound of the brain showed a grade IV intraventricular hemorrhage. A review of the nurses’ recordings of heart rate, blood pressure, and respiratory rate showed a progressive increase in blood pressure accompanied by slowing of the heart rate and irregular respiration. These are features of the Cushing reflex that is elicited in response to raised intracranial pressure.

Conclusion

While well-described in older children and adults, in neonates the Cushing reflex has mainly been described in animal experiments and infants who have developed hydrocephalus. It is likely that in this case, the reflex was elicited as a result of a progressive increase in intracranial pressure due to the combination of elevated intrathoracic pressure, obstructed venous return from the brain, and concurrent intraventricular hemorrhage.

Caffeine: cardiorespiratory effects and tissue protection in animal models

The aim of this review is to analyze the cardiorespiratory and tissue-protective effects of caffeine in animal models. Peer-reviewed literature published between 1975 and 2021 was retrieved from CAB Abstracts, PubMed, ISI Web of Knowledge, and Scopus. Extracted data were analyzed to address the mechanism of action of caffeine on cardiorespiratory parameters (heart rate and rhythm), vasopressor effects, and some indices of respiratory function; we close this review by discussing the current debate on the research carried out on the effects of caffeine on tissue protection. Adenosine acts through specific receptors and is a negative inotropic and chronotropic agent. Blockage of its cardiac receptors can cause tachycardia (with arrhythmogenic potential) due to the intense activity of β1 receptors. In terms of tissue protection, caffeine inhibits hyperoxia-induced pulmonary inflammation by decreasing proinflammatory cytokine expression in animal models. The protection that caffeine provides to tissues is not limited to the CNS, as studies have demonstrated that it generates attenuation of inflammatory effects in pulmonary tissue. It inhibits the effects of some pro-inflammatory cytokines and prevents functional and structural changes.

Stimulating and maintaining spontaneous breathing during transition of preterm infants

Most preterm infants breathe at birth, but need additional respiratory support due to immaturity of the lung and respiratory control mechanisms. To avoid lung injury, the focus of respiratory support has shifted from invasive towards non-invasive ventilation. However, applying effective non-invasive ventilation is difficult due to mask leak and airway obstruction. The larynx has been overlooked as one of the causes for obstruction, preventing face mask ventilation from inflating the lung. The larynx remains mostly closed at birth, only opening briefly during a spontaneous breath. Stimulating and supporting spontaneous breathing could enhance the success of non-invasive ventilation by ensuring that the larynx remains open. Maintaining adequate spontaneous breathing and thereby reducing the need for invasive ventilation is not only important directly after birth, but also in the first hours after admission to the NICU. Respiratory distress syndrome is an important cause of respiratory failure. Traditionally, treatment of RDS required intubation and mechanical ventilation to administer exogenous surfactant. However, new ways have been implemented to administer surfactant and preserve spontaneous breathing while maintaining non-invasive support. In this narrative review we aim to describe interventions focused on stimulation and maintenance of spontaneous breathing of preterm infants in the first hours after birth.

Optimizing respiratory management in preterm infants: a review of adjuvant pharmacotherapies

Adjuvant respiratory therapies in preterm neonates aim to reduce long-term morbidities and mortality. Commonly utilized therapies include caffeine, systemic glucocorticosteroids, inhaled steroids, inhaled bronchodilators, and diuretics. This review discusses the available literature that supports some of these practices and points out where clinical practices are not corroborated by evidence. Therapies with no proven clinical benefit must be weighed against potential adverse effects.

Effects of Caffeine on Splanchnic Oxygenation in Preterm Infants

OBJECTIVE

The aim of this study is to assess the effects of administering 20 mg/kg loading dose of caffeine citrate intravenously on splanchnic oxygenation in preterm infants.

STUDY DESIGN

The infants with a gestational age (GA) of <34 weeks who were administered with a 20 mg/kg intravenous loading dose of caffeine citrate within 48 hours after birth were investigated prospectively. Regional splanchnic oxygen saturation (rsSO₂) and splanchnic fractional tissue oxygen extraction rate (sFTOE) were measured using near-infrared spectroscopy before caffeine infusion, immediately after caffeine infusion and 1, 2, 3, 4, and 6 hours (h) after dose completion; postdose values were compared with predose values.

RESULTS

A total of 41 infants with a mean GA of 29.2 ± 1.6 weeks and birth weight of 1,315 ± 257 g as well as postnatal age of 32.2 ± 10.8 hours were included in the study. rsSO₂ significantly reduced from 63.1 to 57.5% immediately after caffeine infusion, 55.1% after 1 hour, and 55.2% after 2 hours with partial recovery at 3-hour postdose. sFTOE increased correspondingly.

CONCLUSION

Caffeine reduces splanchnic oxygenation and increases splanchnic oxygen extraction for at least 2 hours with partial recovery to predose levels at 3-hour postdose.

Effects of Single Loading Dose of Intravenous Caffeine on Cerebral Oxygenation in Preterm Infants

OBJECTIVE

The aim of this study was to evaluate the effects of caffeine on cerebral oxygenation in preterm infants.

STUDY DESIGN

This was a prospective study of infants with a gestational age (GA) of < 34 weeks who were treated intravenously with a loading dose of 20 mg/kg caffeine citrate within the first 48 hours of life. Regional cerebral oxygen saturation (rSO₂C) and cerebral fractional tissue oxygen extraction (cFTOE) were measured using near-infrared spectroscopy before administering caffeine (baseline), immediately after administering caffeine, and 1, 2, 3, 4, 6, and 12 hours after dose completion; postdose values were compared with the baseline values.

RESULTS

A total of 48 infants with a mean GA of 29.0 ± 1.9 weeks, birth weight of 1,286 ± 301 g, and postnatal age of 32.4 ± 11.3 hours were included in the study. rSO₂C significantly decreased from 81.3 to 76.7% soon after administering caffeine, to 77.1% at 1 hour, and to 77.8% at 2 hours with recovery at 3 hours postdose. rSO₂C was 80.2% at 12 hours postdose. cFTOE increased correspondingly. Although rSO₂C values were lower and cFTOE values were higher compared with the baseline values at 3, 4, 6, and 12 hours after caffeine administration, this was not statistically significant.

CONCLUSION

A loading dose of caffeine temporarily reduces cerebral oxygenation and increases cerebral tissue oxygen extraction in preterm infants. Most probably these changes reflect a physiological phenomenon without any clinical importance to the cerebral hemodynamics, as the reduction in cerebral oxygenation and increase in cerebral tissue oxygen extraction remain well within acceptable range.

Early High-Dose Caffeine Improves Respiratory Outcomes in Preterm Infants

The objective of the study is to determine if early high-dose caffeine (HD) therapy is associated with shorter duration of mechanical ventilation, bronchopulmonary dysplasia (BPD), or decreased need for mechanical ventilation. We conducted a single center, retrospective cohort study of 273 infants less than 32 weeks gestational age (GA). Infants receiving early HD (10 mg/kg/day maintenance) caffeine citrate started within 24 h of life were compared with those receiving LD (6 mg/kg/day) with variable timing of initiation using linear and logistic regression models. The infants in the early HD group had 91.4 (95% confidence interval (CI): −166.6, −16.1; p = 0.018) less hours of mechanical ventilation up to 36 weeks PMA or discharge as compared with the LD group. Moreover, infants in the HD group had 0.37 (95% CI: 0.14, 0.97; p = 0.042) times lower odds of developing moderate/severe BPD compared with the LD group. Infants receiving early HD caffeine had improved respiratory outcomes with no increase in measured comorbidities. Large prospective studies are needed to determine the long-term outcomes of using high-dose caffeine prophylaxis for preterm infants.

Surfactant protein D and bronchopulmonary dysplasia: a new way to approach an old problem

Surfactant protein D (SP-D) is a collectin protein synthesized by alveolar type II cells in the lungs. SP-D participates in the innate immune defense of the lungs by helping to clear infectious pathogens and modulating the immune response. SP-D has shown an anti-inflammatory role by down-regulating the release of pro-inflammatory mediators in different signaling pathways such as the TLR4, decreasing the recruitment of inflammatory cells to the lung, and modulating the oxidative metabolism in the lungs. Recombinant human SP-D (rhSP-D) has been successfully produced mimicking the structure and functions of native SP-D. Several in vitro and in vivo experiments using different animal models have shown that treatment with rhSP-D reduces the lung inflammation originated by different insults, and that rhSP-D could be a potential treatment for bronchopulmonary dysplasia (BPD), a rare disease for which there is no effective therapy up to date. BPD is a complex disease in preterm infants whose incidence increases with decreasing gestational age at birth. Lung inflammation, which is caused by different prenatal and postnatal factors like infections, lung hyperoxia and mechanical ventilation, among others, is the key player in BPD. Exacerbated inflammation causes lung tissue injury that results in a deficient gas exchange in the lungs of preterm infants and frequently leads to long-term chronic lung dysfunction during childhood and adulthood. In addition, low SP-D levels and activity in the first days of life in preterm infants have been correlated with a worse pulmonary outcome in BPD. Thus, SP-D mediated functions in the innate immune response could be critical aspects of the pathogenesis in BPD and SP-D could inhibit lung tissue injury in this preterm population. Therefore, administration of rhSP-D has been proposed as promising therapy that could prevent BPD.

Prophylactic versus therapeutic caffeine for apnea of prematurity: a randomized controlled trial

BACKGROUND

Therapeutic initiation of methyxanthines for treatment of apnea in preterm infants was the standard policy. Caffeine therapy is beneficial for various outcomes of preterm infants.

AIM

To evaluate the efficacy of early prophylactic compared to routine therapeutic caffeine therapy on duration of oxygen support and other outcomes of preterm infants.

METHODS

In a randomized controlled trial including preterm infants < 32 weeks' gestation, prophylactic (in the first 72 h of life) versus therapeutic (only if apnea exists or infant requires mechanical ventilation) decision of caffeine was compared. The primary outcome was the duration of oxygen therapy. Secondary outcomes included duration of respiratory support modalities; bronchoplumonary dysplasia (BPD); necrotizing enterocolitis; intra-ventricular hemorrhage; retinopathy of prematurity; length of hospital stay (LOS); neonatal mortality; and caffeine side effects.

RESULTS

We enrolled 90 infants in the prophylactic and 91 infants in therapeutic groups respectively. Prophylactic caffeine decreased the duration of oxygen therapy [median and IQR of 28 (18-36) days versus 34 (23-51) days, p = .005 respectively]. Prophylactic caffeine significantly decreased the durations of respiratory support modalities, LOS, and incidences of mild to moderate BPD without reported effects on the incidence of severe BPD or other clinical outcomes compared to therapeutic caffeine. A significantly higher proportion of infants in the prophylactic caffeine group did not require mechanical ventilation during their NICU admission and a significant lower proportion required late mechanical ventilation compared to the prophylactic caffeine group.

CONCLUSION

Prophylactic caffeine decreased the duration of oxygen therapy, invasive and noninvasive ventilation, incidences of mild to moderate BPD, and LOS in preterm infants.

Potential Effects of Nutraceuticals in Retinopathy of Prematurity

Retinopathy of prematurity (ROP), the most common cause of childhood blindness, is a hypoxia-induced eye disease characterized by retinal neovascularization. In the normal retina, a well-organized vascular network provides oxygen and nutrients as energy sources to maintain a normal visual function; however, it is disrupted when pathological angiogenesis is induced in ROP patients. Under hypoxia, inadequate oxygen and energy supply lead to oxidative stress and stimulate neovasculature formation as well as affecting the function of photoreceptors. In order to meet the metabolic needs in the developing retina, protection against abnormal vascular formation is one way to manage ROP. Although current treatments provide beneficial effects in reducing the severity of ROP, these invasive therapies may also induce life-long consequences such as systemic structural and functional complications as well as neurodevelopment disruption in the developing infants. Nutritional supplements for the newborns are a novel concept for restoring energy supply by protecting the retinal vasculature and may lead to better ROP management. Nutraceuticals are provided in a non-invasive manner without the developmental side effects associated with current treatments. These nutraceuticals have been investigated through various in vitro and in vivo methods and are indicated to protect retinal vasculature. Here, we reviewed and discussed how the use of these nutraceuticals may be beneficial in ROP prevention and management.

Enteral Vitamin A for Reducing Severity of Bronchopulmonary Dysplasia: A Randomized Trial

BACKGROUND AND OBJECTIVES

Evidence suggests that intramuscular vitamin A reduces the risk of bronchopulmonary dysplasia (BPD) in preterm infants. Our objective was to compare enteral water-soluble vitamin A with placebo supplementation to reduce the severity of BPD in extremely preterm infants.

METHODS

We conducted a double-blind randomized controlled trial in infants <28 weeks' gestation who were to receive either enteral water-soluble vitamin A (5000 IU per day) or a placebo. Supplementation was started within 24 hours of introduction of feeds and continued until 34 weeks' postmenstrual age (PMA). The primary outcome was the severity of BPD, assessed by using the right shift of the pulse oximeter saturation versus the inspired oxygen pressure curve.

RESULTS

A total of 188 infants were randomly assigned. The mean ± SD birth weight (852 ± 201 vs 852 ± 211 g) and gestation (25.8 ± 1.49 vs 26.0 ± 1.39 weeks) were comparable between the vitamin A and placebo groups. There was no difference in the right shift (median [25th-75th percentiles]) of the pulse oximeter saturation versus inspired oxygen pressure curve (in kilopascals) between the vitamin A (11.1 [9.5-13.7]) and placebo groups (10.7 [9.5-13.1]) (P = .73). Enteral vitamin A did not affect diagnosis of BPD or other clinical outcomes. Plasma retinol levels were significantly higher in the vitamin A group versus the placebo group on day 28 and at 34 weeks' PMA.

CONCLUSIONS

Enteral water-soluble vitamin A supplementation improves plasma retinol levels in extremely preterm infants but does not reduce the severity of BPD.

A Prediction Model of Extubation Failure Risk in Preterm Infants

Objectives: This study aimed to identify variables and develop a prediction model that could estimate extubation failure (EF) in preterm infants. Study Design: We enrolled 128 neonates as a training cohort and 58 neonates as a validation cohort. They were born between 2015 and 2020, had a gestational age between 25^0/7 and 29^6/7 weeks, and had been treated with mechanical ventilation through endotracheal intubation (MVEI) because of acute respiratory distress syndrome. In the training cohort, we performed univariate logistic regression analysis along with stepwise discriminant analysis to identify EF predictors. A monogram based on five predictors was built. The concordance index and calibration plot were used to assess the efficiency of the nomogram in the training and validation cohorts. Results: The results of this study identified a 5-min Apgar score, early-onset sepsis, hemoglobin before extubation, pH before extubation, and caffeine administration as independent risk factors that could be combined for accurate prediction of EF. The EF nomogram was created using these five predictors. The area under the receiver operator characteristic curve was 0.824 (95% confidence interval 0.748-0.900). The concordance index in the training and validation cohorts was 0.824 and 0.797, respectively. The calibration plots showed high coherence between the predicted probability of EF and actual observation. Conclusions: This EF nomogram was a useful model for the precise prediction of EF risk in preterm infants who were between 25^0/7 and 29^6/7 weeks' gestational age and treated with MVEI because of acute respiratory distress syndrome.

Encephalopathy in Preterm Infants: Advances in Neuroprotection With Caffeine

With the improvement in neonatal rescue technology, the survival rate of critically ill preterm infants has substantially increased; however, the incidence of brain injury and sequelae in surviving preterm infants has concomitantly increased. Although the etiology and pathogenesis of preterm brain injury, and its prevention and treatment have been investigated in recent years, powerful and effective neuroprotective strategies are lacking. Caffeine is an emerging neuroprotective drug, and its benefits have been widely recognized; however, its effects depend on the dose of caffeine administered, the neurodevelopmental stage at the time of administration, and the duration of exposure. The main mechanisms of caffeine involve adenosine receptor antagonism, phosphodiesterase inhibition, calcium ion activation, and γ-aminobutyric acid receptor antagonism. Studies have shown that there are both direct and indirect beneficial effects of caffeine on the immature brain. Accordingly, this article briefly reviews the pharmacological characteristics of caffeine, its mechanism of action in the context of encephalopathy in premature infants, and its use in the neuroprotection of encephalopathy in this patient population.

What is bronchopulmonary dysplasia and does caffeine prevent it?

Bronchopulmonary dysplasia (BPD) is among the most severe complications of very premature birth. Clinical and laboratory studies indicate that lung immaturity, inflammatory lung injury, and disordered lung repair are the primary mechanisms responsible for the development of BPD. Caffeine, initiated within the first 10 days after birth, is one of few drug therapies shown to significantly decrease the risk of BPD in very low birth weight infants. This benefit is likely derived, at least in part, from reduced exposure to positive airway pressure and supplemental oxygen with caffeine therapy. Additional cardiorespiratory benefits of caffeine that may contribute to the lower risk of BPD include less frequent treatment for a PDA, improved pulmonary mechanics, and direct effects on pulmonary inflammation, alveolarization, and angiogenesis. Routine administration of caffeine is indicated in the vast majority of very low birth weight infants. However, current preventative strategies including widespread use of caffeine do not avert BPD in all cases. As such, there is continued need for novel methods to further reduce the risk of BPD in very low birth weight infants.

National and international guidelines for neonatal caffeine use: Are they evidenced-based?

The Caffeine for Apnea of Prematurity (CAP) trial showed that caffeine was safe when used with standard dosing and provided both pulmonary and neurological benefits to preterm infants. Since its publication almost 15 years ago, the use of caffeine in extremely premature infants in Newborn Intensive Care Units worldwide has increased, with almost all receiving the drug during their hospital stay. Subsequent observational studies suggested that administration of caffeine before 3 days of age may have greater benefits, leading many neonatologists to start caffeine prophylactically in all very low birth weight infants. Several publicly available national and international guidelines on caffeine advocate prophylactic use, and some recommend higher doses than those used in the CAP trial. This article will review the evidence basis for neonatal caffeine therapy in light of these guidelines.

When to start and stop caffeine and why respiratory status matters

Caffeine as tested in the CAP trial is safe and effective for preterm infants with birthweights less than 1250 g. Evidence for its use beyond the indications and timing used in this trial is of low quality and conflicting. Some studies suggest that earlier use of caffeine increases the risk of mortality while others suggest it has important benefits. It appears that infants with apnea of prematurity and those receiving assisted ventilation are the most likely to benefit from caffeine. Based on currently available evidence, routine early prescription of caffeine does not appear to be indicated. Infants continue to have potentially damaging episodes of hypoxia secondary to apnea beyond 34 weeks' postmenstrual age. It is unclear whether prolonged use of caffeine improves outcomes in these infants. Randomized trials to resolve these uncertainties are required. They need to be large, at least the size of the CAP trial, and include neurodevelopmental outcomes.

Can pentoxifylline and similar xanthine derivatives find a niche in COVID-19 therapeutic strategies? A ray of hope in the midst of the pandemic

COVID-19 pandemic presents an unprecedented challenge to identify effective drugs for treatment. Despite multiple clinical trials using different agents, there is still a lack of specific treatment for COVID-19. Having the potential role in suppressing inflammation, immune modulation, antiviral and improving respiratory symptoms, this review discusses the potential role of methylxanthine drugs like pentoxifylline and caffeine in the management of COVID-19 patients. COVID-19 pathogenesis for clinical features like severe pneumonia, acute lung injury (ALI) / acute respiratory distress syndrome (ARDS), and multi-organ failures are excessive inflammation, oxidation, and cytokine storm by the exaggerated immune response. Drugs like pentoxifylline have already shown improvement of the symptoms of ARDS and caffeine has been in clinical use for decades to treat apnea of prematurity (AOP) in preterm infants and improve respiratory function. Pentoxifylline is well-known anti-inflammatory and anti-oxidative molecules that have already shown to suppress Tumor Necrosis Factor (TNF-α) as well as other inflammatory cytokines in pulmonary diseases, and this may be beneficial for better clinical outcomes in COVID-19 patients. Pentoxifylline enhances blood flow, improves microcirculation and tissue oxygenation, and caffeine also efficiently improves tissue oxygenation, asthma, decreases pulmonary hypertension and an effective analgesic. There are significant shreds of evidence that proved the properties of pentoxifylline and caffeine against virus-related diseases as well. Along with the aforementioned evidences and high safety profiles, both pentoxifylline and caffeine offer a glimpse of considerations for future use as a potential adjuvant to COVID-19 treatment. However, additional clinical studies are required to confirm this speculation.

Caffeine citrate maintenance doses effect on extubation and apnea postventilation in preterm infants

BACKGROUND

Caffeine citrate is used to prevent apnea in premature infants and help in extubation of invasive ventilation, but the optimal dose remains undetermined.

METHODS

Neonates born at less than 30 weeks gestation who had received invasive ventilation for at least 48 hours and a loading dose of 20 mg/kg caffeine citrate were randomly assigned into high (10 mg/kg daily) or low (5 mg/kg daily) maintenance dose groups. The drug was discontinued if no apnea occurred for 7 consecutive days.

RESULTS

A total of 111 infants were assigned into the high (54) or low (57) dose groups. Extubation failure (16.7% vs 36.8%), age of extubation (8.2 ± 2.1 vs 10.7 ± 2.3 day), duration of invasive ventilation (7.2 ± 2.1 vs 8.5 ± 2.4 day), duration of ventilation before extubation (8.0 ± 1.8 vs 10.1 ± 1.9 day), and number of days of apnea (1.8 ± 1.3 vs 3.2 ± 1.1 day) were significantly lower in the high dose group than the low dose group. Difference in time until failure (6.7 ± 1.7d vs 7.0 ± 1.9d) and duration of nasal continuous positive airway pressure(7.8 ± 1.8 vs 8.0 ± 2.2 day) were not significant. Furthermore, no significant differences in the incidence of tachycardia (9.3% vs 12.3%), abdominal distension (16.7% vs 12.3%), feeding intolerance (3.7% vs 5.3%), or irritability (7.4% vs 5.3%) were observed between groups.

CONCLUSIONS

A higher maintenance dose of caffeine citrate reduced the incidence of extubation failure and apnea of prematurity without increasing the occurrence of adverse reactions.

Bronchopulmonary Dysplasia: Then, Now, and Next

Bronchopulmonary dysplasia (BPD) has evolved considerably since its first description over 50 years ago. This review aims to provide a historical framework for conceptualizing BPD and a current understanding of the changing definition, epidemiology, pathophysiology, treatment, and outcomes of BPD. The transdisciplinary approach that led to the initial phenotypic description of BPD continues to hold promise today. Investigators are refining the definition of BPD in light of changes in clinical care and increasing survival rates of very preterm infants. Despite improvements in perinatal care the incidence of BPD continues to increase. There is growing recognition that antenatal risk factors play a key role in the development of BPD. Strategies designed to prevent or limit neonatal lung injury continue to evolve. Defining the phenotype of infants with BPD can meaningfully direct treatment. Infants with BPD benefit from an interdisciplinary approach to longitudinal care with a focus on growth and neurocognitive development. While the ultimate impact of BPD on long-term pulmonary morbidity remains an active area of investigation, current data indicate that most children and adolescents with a history of BPD have a quality of life comparable to that of other preterm infants.

Confounding biases in studies on early- versus late-caffeine in preterm infants: a systematic review

BACKGROUND

Caffeine is indicated for the management of apnoea of prematurity and extubation in preterm infants. Early initiation of caffeine administration has increased in the past decades with the purpose of reducing respiratory morbidity. However, there might be harms associated with this approach. This systematic review aims to assess whether early administration of caffeine reduces morbidity and mortality in preterm infants.

METHODS

The methods were published in a preregistered protocol. The literature search was performed in February 2019 with no restrictions for language or publication date. Randomised controlled trials (RCTs) and cohort studies comparing early versus late caffeine administration to infants born before week 34 were included.

RESULTS

Two RCTs and 14 cohort studies were included. All studies but one had a serious/critical overall risk of bias. Few studies reported on long-term or patient-relevant outcomes. No meta-analysis could be performed.

CONCLUSION

Based on the available evidence, no conclusions about the optimal timing of caffeine administration can be drawn. There are inherent methodological problems in the cohort studies. RCTs are needed to answer the question of optimal timing for caffeine administration in neonatal care. Future trials should focus on outcomes relevant to patients and their families and include long-term outcomes.

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.

[Comparison of the efficacy of domestic and imported caffeine citrate in the treatment of apnea in preterm infants: a prospective randomized double-blind controlled trial]

OBJECTIVE

To compare the efficacy of domestic and imported caffeine citrate in the treatment of apnea in preterm infants.

METHODS

A total of 98 preterm infants with a gestational age of 28 - <34 weeks between April 2018 and December 2019 were enrolled. They were randomly administered with domestic (n=48) or imported caffeine citrate (n=50) within 6 hours after birth. The therapeutic effects, complications, adverse effects and clinical outcomes were compared between the two groups.

RESULTS

There were no significant differences in the incidence of apnea within 7 days after birth, daily frequency of apnea, the time of apnea disappearance, the failure rate of intubation-surfactant-extubation strategy, the time of non-invasive assisted ventilation, the duration of oxygen therapy, the duration of caffeine citrate therapy, the length of hospital stay, blood gas analysis results, liver and kidney function testing results between the two groups (P>0.05). There were no significant differences in the incidence of complications and the mortality rate between the two groups (P>0.05). There was no significant difference in the incidence of adverse effects between the two groups (P>0.05).

CONCLUSIONS

The efficacy and safety of domestic caffeine citrate in the treatment of apnea are similar to those of imported caffeine citrate in preterm infants.

Caffeine Therapy in Preterm Infants: The Dose (and Timing) Make the Medicine

Caffeine is one of the most commonly utilized medications in the NICU. In preterm infants, short-term and long-term pulmonary and neurodevelopmental benefits of therapy are well documented in the literature. While robust evidence supports the use of standard doses of caffeine for apnea of prematurity or to facilitate successful extubation, much remains unknown regarding the boundaries of efficacy and safety for this common therapeutic agent. Escalating dosing regimens seem to provide additional benefit in select infants, but grave toxicity has also been documented with early utilization of high-dose caffeine. Conflicting data exist surrounding the ideal timing of initiation of therapy. Even the widely adhered to discontinuation point has been challenged by data supporting continued use. Until robust data definitively support change, practice should align with current evidence defining clear, safe, and efficacious dosing and timing of caffeine therapy.

Variations in preterm stabilisation practices and caffeine therapy between two European tertiary level neonatal units

AIM

To investigate interinstitutional differences in preterm infant stabilisation between two European tertiary neonatal centres with particular focus on intubation timing, surfactant administration, caffeine therapy and neonatal morbidity and mortality.

METHODS

Retrospective (2012-2014) study of very low birth weight (VLBW) preterm infants admitted to John Radcliffe Hospital (UK centre) and Charité Medical Centre (German centre). Timing of intubation, surfactant and caffeine administration and respiratory outcomes were examined.

RESULTS

Gestational age, birth weight and five-minute Apgar scores of VLBW infants from the UK centre (n = 86) were comparable to those from the German centre (n = 96). Significant differences in antenatal steroid therapy, intubation timing and surfactant therapy were noted. Timing of caffeine initiation differed significantly between centres (median 0 [0-2.5] UK vs. 2 [1.5-4] days German centre); however, caffeine was discontinued at a similar corrected gestational age of 34.7 weeks. Mechanical ventilation was significantly longer at the UK centre, but there was no difference in bronchopulmonary dysplasia (BPD) (44% UK vs. 36% German centre) or mortality (15% UK vs. 13% German centre).

CONCLUSION

Timing of primary intubation and caffeine therapy differed significantly between centres. However, earlier intubation and caffeine administration in the UK centre were not associated with a changed incidence of BPD.

[Safety and efficacy of caffeine use started at different time in preterm infants: a multicenter study in Jiangsu Province, China]

OBJECTIVE

To study the efficacy and safety of caffeine used in the early (≤72 hours after birth) and late (>72 hours after birth) stage in preterm infants with a gestational age of ≤31 weeks.

METHODS

A retrospective analysis was performed for 640 preterm infants (with a gestational age of ≤31 weeks) who were admitted to the neonatal intensive care unit of eight hospitals in Jiangsu Province, China. Of the 640 preterm infants, 510 were given caffeine in the early stage (≤72 hours after birth; early use group) and 130 were given caffeine in the late stage (>72 hours after birth; late use group). The clinical data were compared between the two groups.

RESULTS

There were no significant differences in birth weight, Apgar score, sex, gestational age, and age on admission between the two groups (P>0.05). Compared with the late use group, the early use group had a significantly younger age at the beginning and withdrawal of caffeine treatment (P<0.05) and a significantly shorter duration of caffeine treatment (P<0.05). There was no significant difference in respiratory support on admission between the two groups (P>0.05). Compared with the late use group, the early use group had significantly lower incidence rate of apnea (P<0.05) and significantly shorter oxygen supply time and length of hospital stay (P<0.05). There were no significant differences between the two groups in the incidence rates of neonatal intracranial hemorrhage, periventricular leukomalacia, necrotizing enterocolitis, retinopathy of prematurity, and patent ductus arteriosus at discharge and NBNA score at the corrected gestational age of 40 weeks (P>0.05). However, significant differences were found in the incidence of bronchopulmonary dysplasia and the rate of home oxygen therapy, but there was no significant difference in the mortality rate between the two groups (P>0.05).

CONCLUSIONS

Early use of caffeine can shorten the duration of caffeine treatment, oxygen supply time, and length of hospital stay, with little adverse effect, in preterm infants with a gestational age of ≤31 weeks.

Caffeine in preterm infants: where are we in 2020?

The incidence of preterm birth is increasing, leading to a growing population with potential long-term pulmonary complications. Apnoea of prematurity (AOP) is one of the major challenges when treating preterm infants; it can lead to respiratory failure and the need for mechanical ventilation. Ventilating preterm infants can be associated with severe negative pulmonary and extrapulmonary outcomes, such as bronchopulmonary dysplasia (BPD), severe neurological impairment and death. Therefore, international guidelines favour non-invasive respiratory support. Strategies to improve the success rate of non-invasive ventilation in preterm infants include pharmacological treatment of AOP. Among the different pharmacological options, caffeine citrate is the current drug of choice. Caffeine is effective in reducing AOP and mechanical ventilation and enhances extubation success; it decreases the risk of BPD; and is associated with improved cognitive outcome at 2 years of age, and pulmonary function up to 11 years of age. The commonly prescribed dose (20 mg·kg-1 loading dose, 5-10 mg·kg-1 per day maintenance dose) is considered safe and effective. However, to date there is no commonly agreed standardised protocol on the optimal dosing and timing of caffeine therapy. Furthermore, despite the wide pharmacological safety profile of caffeine, the role of therapeutic drug monitoring in caffeine-treated preterm infants is still debated. This state-of-the-art review summarises the current knowledge of caff-eine therapy in preterm infants and highlights some of the unresolved questions of AOP. We speculate that with increased understanding of caffeine and its metabolism, a more refined respiratory management of preterm infants is feasible, leading to an overall improvement in patient outcome.