The application of continuous positive airway pressure (CPAP) has been shown to have some benefits in the treatment of preterm infants with respiratory distress. CPAP has the potential to reduce lung ...damage, particularly if applied early before atelectasis has occurred. Early application may better conserve an infant's own surfactant stores and consequently may be more effective than later application.
• To determine if early compared with delayed initiation of CPAP results in lower mortality and reduced need for intermittent positive-pressure ventilation in preterm infants in respiratory distress ○ Subgroup analyses were planned a priori on the basis of weight (with subdivisions at 1000 grams and 1500 grams), gestation (with subdivisions at 28 and 32 weeks), and according to whether surfactant was used ▫ Sensitivity analyses based on trial quality were also planned ○ For this update, we have excluded trials using continuous negative pressure SEARCH METHODS: We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 6), in the Cochrane Library; Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations Daily and Versions(R); and the Cumulative Index to Nursing and Allied Health Literatue (CINAHL), on 30 June 2020. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.
We included trials that used random or quasi-random allocation to either early or delayed CPAP for spontaneously breathing preterm infants in respiratory distress.
We used the standard methods of Cochrane and Cochrane Neonatal, including independent assessment of trial quality and extraction of data by two review authors. We used the GRADE approach to assess the certainty of evidence.
We found four studies that recruited a total of 119 infants. Two were quasi-randomised, and the other two did not provide details on the method of randomisation or allocation used. None of these studies used blinding of the intervention or the outcome assessor. Evidence showed uncertainty about whether early CPAP has an effect on subsequent use of intermittent positive-pressure ventilation (IPPV) (typical risk ratio (RR) 0.77, 95% confidence interval (CI) 0.43 to 1.38; typical risk difference (RD) -0.08, 95% CI -0.23 to 0.08; I² = 0%, 4 studies, 119 infants; very low-certainty evidence) or mortality (typical RR 0.93, 95% CI 0.43 to 2.03; typical RD -0.02, 95% CI -0.15 to 0.12; I² = 33%, 4 studies, 119 infants; very low-certainty evidence). The outcome 'failed treatment' was not reported in any of these studies. There was an uncertain effect on air leak (pneumothorax) (typical RR 1.09, 95% CI 0.39 to 3.04, I² = 0%, 3 studies, 98 infants; very low-certainty evidence). No trials reported intraventricular haemorrhage or necrotising enterocolitis. No cases of retinopathy of prematurity were reported in one study (21 infants). One case of bronchopulmonary dysplasia was reported in each group in one study involving 29 infants. Long-term outcomes were not reported.
All four small trials included in this review were performed in the 1970s or the early 1980s, and we are very uncertain whether early application of CPAP confers clinical benefit in the treatment of respiratory distress, or whether it is associated with any adverse effects. Further trials should be directed towards establishing the appropriate level of CPAP and the timing and method of administration of surfactant when used along with CPAP.
The use of supplemental oxygen in the care of extremely preterm infants has been common practice since the 1940s. Despite this, there is little agreement regarding which oxygen saturation (SpO₂) ...ranges to target to maximise short- or long-term growth and development, while minimising harms. There are two opposing concerns. Lower oxygen levels (targeting SpO₂ at 90% or less) may impair neurodevelopment or result in death. Higher oxygen levels (targeting SpO₂ greater than 90%) may increase severe retinopathy of prematurity or chronic lung disease.The use of pulse oximetry to non-invasively assess neonatal SpO₂ levels has been widespread since the 1990s. Until recently there were no randomised controlled trials (RCTs) that had assessed whether it is better to target higher or lower oxygen saturation levels in extremely preterm infants, from birth or soon thereafter. As a result, there is significant international practice variation and uncertainty remains as to the most appropriate range to target oxygen saturation levels in preterm and low birth weight infants.
1. What are the effects of targeting lower versus higher oxygen saturation ranges on death or major neonatal and infant morbidities, or both, in extremely preterm infants?2. Do these effects differ in different types of infants, including those born at a very early gestational age, or in those who are outborn, without antenatal corticosteroid coverage, of male sex, small for gestational age or of multiple birth, or by mode of delivery?
We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 4), MEDLINE via PubMed (1966 to 11 April 2016), Embase (1980 to 11 April 2016) and CINAHL (1982 to 11 April 2016). We also searched clinical trials databases, conference proceedings and the reference lists of retrieved articles for randomised controlled trials.
Randomised controlled trials that enrolled babies born at less than 28 weeks' gestation, at birth or soon thereafter, and targeted SpO₂ ranges of either 90% or below or above 90% via pulse oximetry, with the intention of maintaining such targets for at least the first two weeks of life.
We used the standard methods of Cochrane Neonatal to extract data from the published reports of the included studies. We sought some additional aggregate data from the original investigators in order to align the definitions of two key outcomes. We conducted the meta-analyses with Review Manager 5 software, using the Mantel-Haenszel method for estimates of typical risk ratio (RR) and risk difference (RD) and a fixed-effect model. We assessed the included studies using the Cochrane 'Risk of bias' and GRADE criteria in order to establish the quality of the evidence. We investigated heterogeneity of effects via pre-specified subgroup and sensitivity analyses.
Five trials, which together enrolled 4965 infants, were eligible for inclusion. The investigators of these five trials had prospectively planned to combine their data as part of the NeOProM (Neonatal Oxygen Prospective Meta-analysis) Collaboration. We graded the quality of evidence as high for the key outcomes of death, major disability, the composite of death or major disability, and necrotising enterocolitis; and as moderate for blindness and retinopathy of prematurity requiring treatment.When an aligned definition of major disability was used, there was no significant difference in the composite primary outcome of death or major disability in extremely preterm infants when targeting a lower (SpO₂ 85% to 89%) versus a higher (SpO₂ 91% to 95%) oxygen saturation range (typical RR 1.04, 95% confidence interval (CI) 0.98 to 1.10; typical RD 0.02, 95% CI -0.01 to 0.05; 5 trials, 4754 infants) (high-quality evidence). Compared with a higher target range, a lower target range significantly increased the incidence of death at 18 to 24 months corrected age (typical RR 1.16, 95% CI 1.03 to 1.31; typical RD 0.03, 95% CI 0.01 to 0.05; 5 trials, 4873 infants) (high-quality evidence) and necrotising enterocolitis (typical RR 1.24, 95% 1.05 to 1.47; typical RD 0.02, 95% CI 0.01 to 0.04; 5 trials, 4929 infants; I² = 0%) (high-quality evidence). Targeting the lower range significantly decreased the incidence of retinopathy of prematurity requiring treatment (typical RR 0.72, 95% CI 0.61 to 0.85; typical RD -0.04, 95% CI -0.06 to -0.02; 5 trials, 4089 infants; I² = 69%) (moderate-quality evidence). There were no significant differences between the two treatment groups for major disability including blindness, severe hearing loss, cerebral palsy, or other important neonatal morbidities.A subgroup analysis of major outcomes by type of oximeter calibration software (original versus revised) found a significant difference in the treatment effect between the two software types for death (interaction P = 0.03), with a significantly larger treatment effect seen for those infants using the revised algorithm (typical RR 1.38, 95% CI 1.13 to 1.68; typical RD 0.06, 95% CI 0.01 to 0.10; 3 trials, 1716 infants). There were no other important differences in treatment effect shown by the subgroup analyses using the currently available data.
In extremely preterm infants, targeting lower (85% to 89%) SpO₂ compared to higher (91% to 95%) SpO₂ had no significant effect on the composite outcome of death or major disability or on major disability alone, including blindness, but increased the average risk of mortality by 28 per 1000 infants treated. The trade-offs between the benefits and harms of the different oxygen saturation target ranges may need to be assessed within local settings (e.g. alarm limit settings, staffing, baseline outcome risks) when deciding on oxygen saturation targeting policies.
Recent satellite and hydrographic observations have shown that the rate of freshwater accumulation in the Beaufort Gyre of the Arctic Ocean has accelerated over the past decade. This acceleration has ...coincided with the dramatic decline observed in Arctic sea ice cover, which is expected to modify the efficiency of momentum transfer into the upper ocean. Here, a simple process model is used to investigate the dynamical response of the Beaufort Gyre to the changing efficiency of momentum transfer, and its link with the enhanced accumulation of freshwater. A linear relationship is found between the annual mean momentum flux and the amount of freshwater accumulated in the Beaufort Gyre. In the model, both the response time scale and the total quantity of freshwater accumulated are determined by a balance between Ekman pumping and an eddyinduced volume flux toward the boundary, highlighting the importance of eddies in the adjustment of the Arctic Ocean to a change in forcing. When the seasonal cycle in the efficiency of momentum transfer is modified (but the annual mean momentum flux is held constant), it has no effect on the accumulation of freshwater, although it does impact the timing and amplitude of the annual cycle in Beaufort Gyre freshwater content. This suggests that the decline in Arctic sea ice cover may have an impact on the magnitude and seasonality of the freshwater export into the North Atlantic.
Background
Clinical and radiographic criteria are traditionally used to determine the need for surfactant therapy in preterm infants. Lung ultrasound is a bedside test that offers a rapid, ...radiation‐free, alternative to this approach.
Objective
To conduct a systematic review and meta‐analysis to determine the accuracy of a lung ultrasound score (LUS) in identifying infants who would receive at least one surfactant dose. Secondary aims were to evaluate the predictive accuracy for ≥2 doses and the accuracy of a different image classification system based on three lung ultrasound profiles.
Methods
PubMed, SCOPUS, Biomed Central, and the Cochrane library between January 2011 and December 2021 were searched. Full articles enrolling preterm neonates who underwent lung ultrasound to predict surfactant administration were assessed and analyzed following Preferred Reporting Items for Systematic Review and Meta‐Analysis Protocols (PRISMA‐P) and QUADAS‐2 guidelines.
Results
Seven prospective studies recruiting 697 infants met the inclusion criteria. Risk of bias was generally low. Oxygen requirement, clinical and radiographic signs of respiratory distress syndrome were used as reference standards for surfactant replacement. The summary receiver operator characteristic (sROC) curve for LUS predicting first surfactant dose showed an area under the curve (AUC) = 0.88 (95% confidence interval CI: 0.82–0.91); optimal specificity and sensitivity (Youden index) were 0.83 and 0.81 respectively. Pooled estimates of sensitivity, specificity, diagnostic odds ratio, negative predictive value, and positive predictive value for LUS predicting the first surfactant dose were 0.89 (0.82–0.95), 0.86 (0.78–0.95), 3.78 (3.05–4.50), 0.92 (0.87–0.97), 0.79 (0.65–0.92). The sROC curve for the accuracy of Type 1 lung profile in predicting first surfactant dose showed an AUC of 0.88; optimal specificity and sensitivity were both 0.86. Two studies addressing the predictive accuracy of LUS for ≥2 surfactant doses had high heterogeneity and were unsuitable to combine in a meta‐analysis.
Discussion
Despite current significant variation in LUS thresholds, lung ultrasound is highly predictive of the need for early surfactant replacement. This evidence was derived from studies with homogeneous patient characteristics and low risk of bias.
Respiratory distress syndrome (RDS) is the single most important cause of morbidity and mortality in preterm infants. In infants with progressive respiratory insufficiency, intermittent positive ...pressure ventilation (IPPV) with surfactant is the standard treatment for the condition, but it is invasive, potentially resulting in airway and lung injury. Continuous distending pressure (CDP) has been used for the prevention and treatment of RDS, as well as for the prevention of apnoea, and in weaning from IPPV. Its use in the treatment of RDS might reduce the need for IPPV and its sequelae.
To determine the effect of continuous distending pressure (CDP) on the need for IPPV and associated morbidity in spontaneously breathing preterm infants with respiratory distress.Subgroup analyses were planned on the basis of birth weight (> or < 1000 or 1500 g), gestational age (groups divided at about 28 weeks and 32 weeks), methods of application of CDP (i.e. CPAP and CNP), application early versus late in the course of respiratory distress and high versus low pressure CDP and application of CDP in tertiary compared with non-tertiary hospitals, with the need for sensitivity analysis determined by trial quality.At the 2008 update, the objectives were modified to include preterm infants with respiratory failure.
We used the standard search strategy of the Neonatal Review Group. This included searches of the Oxford Database of Perinatal Trials, the Cochrane Central Register of Controlled Trials (CENTRAL, 2015 Issue 4), MEDLINE (1966 to 30 April 2015) and EMBASE (1980 to 30 April 2015) with no language restriction, as well as controlled-trials.com, clinicaltrials.gov and the International Clinical Trials Registry Platform of the World Health Organization (WHO).
All random or quasi-random trials of preterm infants with respiratory distress were eligible. Interventions were continuous distending pressure including continuous positive airway pressure (CPAP) by mask, nasal prong, nasopharyngeal tube or endotracheal tube, or continuous negative pressure (CNP) via a chamber enclosing the thorax and the lower body, compared with spontaneous breathing with oxygen added as necessary.
We used standard methods of The Cochrane Collaboration and its Neonatal Review Group, including independent assessment of trial quality and extraction of data by each review author.
We included six studies involving 355 infants - two using face mask CPAP, two CNP, one nasal CPAP and one both CNP (for less ill babies) and endotracheal CPAP (for sicker babies). For this update, we included no new trials.Continuous distending pressure (CDP) is associated with lower risk of treatment failure (death or use of assisted ventilation) (typical risk ratio (RR) 0.65, 95% confidence interval (CI) 0.52 to 0.81; typical risk difference (RD) -0.20, 95% CI -0.29 to -0.10; number needed to treat for an additional beneficial outcome (NNTB) 5, 95% CI 4 to 10; six studies; 355 infants), lower overall mortality (typical RR 0.52, 95% CI 0.32 to 0.87; typical RD -0.15, 95% CI -0.26 to -0.04; NNTB 7, 95% CI 4 to 25; six studies; 355 infants) and lower mortality in infants with birth weight above 1500 g (typical RR 0.24, 95% CI 0.07 to 0.84; typical RD -0.28, 95% CI -0.48 to -0.08; NNTB 4, 95% CI 2.00 to 13.00; two studies; 60 infants). Use of CDP is associated with increased risk of pneumothorax (typical RR 2.64, 95% CI 1.39 to 5.04; typical RD 0.10, 95% CI 0.04 to 0.17; number needed to treat for an additional harmful outcome (NNTH) 17, 95% CI 17.00 to 25.00; six studies; 355 infants). We found no difference in bronchopulmonary dysplasia (BPD), defined as oxygen dependency at 28 days (three studies, 260 infants), as well as no difference in outcome at nine to 14 years (one study, 37 infants).
In preterm infants with respiratory distress, the application of CDP as CPAP or CNP is associated with reduced respiratory failure and mortality and an increased rate of pneumothorax. Four out of six of these trials were done in the 1970s. Therefore, the applicability of these results to current practice is difficult to assess. Further research is required to determine the best mode of administration.
Understanding ice shelf water (ISW) structure is crucial for studying the basal melting of ice shelves. In this study, we performed large‐eddy simulation experiments to assess ISW structure and basal ...melt patterns under different current velocity scenarios observed in the Larsen C ice shelf, Antarctica. The LES results revealed that the thickness of ISW is primarily determined by the meridional velocity (perpendicular to the grounding line), while the zonal velocity influences the potential temperature and salinity of ISW. We found that a key parameter determining the basal melt rate was northward meltwater advection which originates from variances in meltwater generation. This advection, in turn, leads to the tilted isopycnals and the potential for thermohaline interleaving in a diffusive convection regime. The different slopes of isopycnals induce distinct heat fluxes, resulting in different basal melt rates far from and near the grounding line (∼0.44 and 1.59 m yr−1, respectively).
Plain Language Summary
The loss of ice mass from the Antarctic ice sheet is accelerating, posing a threat to human lives through global sea level rise. Understanding ice shelf water (ISW), which refers to seawater below freezing temperature, is crucial as it directly or indirectly influences basal ice melting. However, direct observations are extremely challenging, leaving this understanding unclear. To tackle this issue, we utilized a numerical model to gain insight into the fundamental characteristics of ISW. We demonstrated that the direction and magnitude of ocean currents beneath the ice shelf play a significant role in determining the thickness and properties of ISW. Moreover, the key factor in basal melting was the northward movement of meltwater from intense ice melting regions near the grounding line. This movement determined the spatial distribution of ocean temperature and salinity. The horizontal gradient of ocean temperature and salinity induces mixing and horizontal intrusion. Interestingly, these mixing and intrusion phenomena occur in opposite directions, resulting in a wiggling pattern in the velocity profile. The main findings of our study will contribute to the formulation of a parameterization for basal melting, which can be incorporated into large‐scale ocean models or ice sheet dynamics models.
Key Points
Direction and magnitude of ocean currents beneath an Larsen C ice shelf affect the ice shelf water thickness and properties
Northward meltwater advection causes 0.052°C difference of thermal drivings with different melt rates far from and near the grounding line
Ocean heat intrusion to ice shelf base is induced by Ekman dynamics and thermohaline interleaving by tilted isopycnals
Previous randomised trials and meta-analyses have shown nasal continuous positive airway pressure (NCPAP) to be a useful method of respiratory support after extubation. However, infants managed in ...this way sometimes 'fail' and require endotracheal reintubation with its attendant risks and expense. Nasal intermittent positive pressure ventilation (NIPPV) is a method of augmenting NCPAP by delivering ventilator breaths via nasal prongs. Older children and adults with chronic respiratory failure benefit from NIPPV and the technique has been applied to neonates. However, serious side effects including gastric perforation have been reported with older techniques to provide NIPPV.
To determine the effect of management with NIPPV compared with NCPAP on the need for additional ventilatory support in preterm infants having their endotracheal tube removed following a period of intermittent positive pressure ventilation.To compare the rates of gastric distension, gastrointestinal perforation, necrotising enterocolitis, chronic lung disease, duration of hospitalisation, rates of apnoea, air leaks and mortality between NIPPV and NCPAP.
We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 7, 2013), MEDLINE (1966 to 4 September 2013), EMBASE (1980 to 4 September 2013), CINAHL (1982 week 3 to August 2013) and PubMed (4 September 2013). We searched previous reviews including cross-references, and conference and symposia proceedings. We contacted experts in the field. We also searched Clinicaltrials.gov for any ongoing trials.
We included randomised and quasi-randomised trials comparing the use of NIPPV with NCPAP in preterm infants being extubated. NIPPV included non-invasive support delivered by a mechanical ventilator or a bilevel device in a synchronised or non-synchronised way. Participants included ventilated preterm infants who were ready to be extubated to non-invasive respiratory support. Interventions compared were NIPPV, either by short nasal prongs or nasopharyngeal tube, and NCPAP, delivered by the same methods.Types of outcomes measures included: failure of therapy (respiratory failure, rates of endotracheal reintubations); gastrointestinal complications (i.e. abdominal distension requiring cessation of feeds, gastrointestinal perforation or necrotising enterocolitis); pulmonary air leaks; chronic lung disease (oxygen requirement at 36 weeks' postmenstrual age) and mortality.
Three review authors independently extracted data regarding clinical outcomes including extubation failure, endotracheal reintubation, rates of apnoea, gastrointestinal perforation, feeding intolerance, necrotising enterocolitis, chronic lung disease, air leaks and duration of hospital stay. We analysed the trials using risk ratio (RR), risk difference (RD) and number needed to treat for an additional beneficial outcome (NNTB) or additional harmful outcome (NNTH) for dichotomous outcomes and mean difference (MD) for continuous outcomes.
The search identified eight trials enrolling 1316 infants in total and comparing extubation of infants to NIPPV or NCPAP. Five trials used the synchronised form of NIPPV, two trials used the non-synchronised form and one trial used both methods. Six studies used NIPPV delivered by a ventilator, one study used a bilevel device and one study used both methods. When all studies were included, the meta-analysis demonstrated a statistically and clinically significant reduction in the risk of meeting extubation failure criteria (typical RR 0.71, 95% CI 0.61 to 0.82; typical RD -0.12, 95% CI -0.17 to -0.07; NNTB 8, 95% CI 6 to 14; 8 trials, 1301 infants) and needing reintubation (typical RR 0.76, 95% CI 0.65 to 0.88; typical RD -0.10, 95% CI -0.15 to -0.05; NNTB 10, 95% CI 7 to 20; 8 trials, 1301 infants). While the method of synchronisation varied (Graseby capsule or pneumotachograph/flow-trigger), the five trials that synchronised NIPPV showed a statistically significant benefit for infants extubated to NIPPV in terms of prevention of extubation failure up to one week after extubation. NIPPV provided via a ventilator appeared more beneficial than bilevel devices in reducing extubation failure in the first week. There was no significant reduction in the rates of chronic lung disease (typical RR 0.97, 95% CI 0.83 to 1.14; typical RD -0.01, 95% CI -0.07 to 0.05), death or difference in the incidence of necrotising enterocolitis between interventions. There was a reduction in air leaks in infants randomised to NIPPV (typical RR 0.50, 95% CI 0.28 to 0.89; typical RD -0.03; 95% CI -0.05 to -0.01; NNTB 33, 95% CI 20 to 100).
NIPPV reduces the incidence of symptoms of extubation failure and need for reintubation within 48 hours to one week more effectively than NCPAP; however, it has no effect on chronic lung disease or mortality. Synchronisation may be important in delivering effective NIPPV. The device used to deliver NIPPV may also be important; however, there are insufficient data to support strong conclusions. NIPPV does not appear to be associated with increased gastrointestinal side effects.
the impact of synchronisation of NIPPV on the technique's safety and efficacy should be established in large trials. The efficacy of bilevel devices should be compared with NIPPV provided by a ventilator in trials. The best combination of settings for NIPPV needs to be established in future trials.
Global fibre supply increased to 113 million tonnes in 2021, contributing to elevated energy and water consumption levels, agricultural pollution, and post-consumer textile waste. Introducing ...second-hand clothing as an alternative to mitigate textile waste is advantageous for providing affordable clothing. However, the disposal of substandard and unsold garments obstructs riverways and drainage systems, leading to flooding. Moreover, incineration produces heightened greenhouse gas emissions, exacerbating poverty and impeding development, particularly in Africa. Nevertheless, textile wastes present opportunities for establishing large-scale regeneration and recycling facilities, offering the potential for employment generation and skill development in Africa. This mini-review aims to underscore Africa’s potential and challenges in textile waste recycling. The findings underscore the importance of recognizing African textile waste, both as an environmental hazard and as a valuable resource for the production of new clothing. Additionally, they emphasize how efforts to add value to recovered textiles are gaining traction, particularly in East, South, and North Africa. However, no formal textile recycling facilities were identified in West and Central Africa. This mini-review is constrained by data limitations, encouraging future researchers to broaden its scope by examining individual countries and recycling companies.
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