OBJECTIVES: To determine if prophylactic nasal CPAP commenced soon after birth regardless of respiratory status in the very preterm or very low birth weight infant reduces the use of IPPV and the incidence of chronic lung disease (CLD) without adverse effects.
SEARCH STRATEGY: The search was updated in April 2005. The standard search strategy of the Neonatal Review Group was used. This included searches of the Oxford Database of Perinatal Trials, Cochrane Library Issue 1 2005, MEDLINE 1966-April 2005, previous reviews including cross references, abstracts, conferences, symposia, proceedings, expert informants, journal hand searching mainly in the English language.
SELECTION CRITERIA: All trials using random or quasi-random patient allocation of very preterm infants < 32 weeks gestation and / or < 1500 gms at birth were eligible. Comparison had to be between prophylactic nasal CPAP commencing soon after birth regardless of the respiratory status of the infant compared with "standard" methods of treatment where CPAP or IPPV is used for a defined respiratory condition.
DATA COLLECTION AND ANALYSIS: Standard methods of the Cochrane Collaboration and its Neonatal Review Group, including independent assessment of trial quality and extraction of data by each author, were used. Data were analysed using relative risk (RR). Meta-analysis was performed using a fixed effects model.
MAIN RESULTS: There are no statistically significant differences in any of the outcomes studied in either of the eligible trials (Han 1987; Sandri 2004) reporting on 82 and 230 infants respectively. In Han 1987 there are trends towards increases in the incidence of BPD at 28 days [RR 2.27 (0.77, 6.65)], death [RR 3.63 (0.42, 31.08)] and any IVH [RR 2.18 (0.84, 5.62)] in the CPAP group. In Sandri 2004 there is a trend towards an increase in IVH grade 3 or 4 [RR 3.0 (0.96, 28.42)] in the CPAP group. No outcome was significantly different in any of the meta-analyses.
AUTHORS' CONCLUSIONS: There is currently insufficient information to evaluate the effectiveness of prophylactic nasal CPAP in very preterm infants. Neither of the included studies reviewed showed evidence of benefit in reducing the use of IPPV. The tendency for some adverse outcomes to be increased is of concern and further multicentre randomized controlled trials are needed to clarify this.
METHODS: A total of 401 whole blood samples with a fresh HbA1c measurement were randomly selected from The Malaysian Cohort's (TMC) biobank. The HbA1c measurements of fresh and frozen (stored for 7-8 years) samples were assayed using different high-performance liquid chromatography (HPLC) systems. The HbA1c values of the fresh samples were then calculated and corrected according to the later system. The reproducibility of HbA1c measurements between calculated-fresh and frozen samples was assessed using a Passing-Bablok linear regression model. The Bland-Altman plot was then used to evaluate the concordance of HbA1c values.
RESULTS: The different HPLC systems highly correlated (r = 0.99) and agreed (ICC = 0.96) with each other. Furthermore, the HbA1c measurements for frozen samples strongly correlate with the corrected HbA1c values of the fresh samples (r = 0.875) with a mean difference of -0.02 (SD: -0.38 to 0.38). Although the mean difference is small, discrepancies were observed within the diabetic and non-diabetic samples.
CONCLUSION: These data demonstrate that the HbA1c measurements between fresh and frozen samples are highly correlated and reproducible.
DESIGN AND STUDY SAMPLE: Study 1 determined ETSPL values in 25 normal-hearing subjects aged 18-25 years at seven test frequencies (500-8000 Hz). Study 2 assessed the intra- and inter-session test-retest threshold reliability in a separate group of 50 adult subjects.
RESULTS: The ETSPL values for the consumer IE deviated from the reference values for audiometric IEs, with the largest differences (7-9 dB) observed at 500 Hz across ear tips. This is likely related to shallow tip insertions. However, test-retest threshold variations were comparable to those reported for audiometric transducers.
CONCLUSIONS: Ear tip-specific corrections to the reference thresholds in the standards are required for calibration of consumer IEs used in low-cost audiometry when their ear tips only allow superficial insertion into the ear canal.
OBJECTIVES: 1. To assess the effects of CPAP on AoP in preterm infants (this may be compared to supportive care or mechanical ventilation). 2. To assess the effects of different CPAP delivery systems on AoP in preterm infants.
SEARCH METHODS: Searches were conducted in September 2022 in the following databases: Cochrane Library, MEDLINE, Embase, and CINAHL. We also searched clinical trial registries and the reference lists of studies selected for inclusion.
SELECTION CRITERIA: We included all randomised and quasi-randomised controlled trials (RCTs) in which researchers determined that CPAP was necessary for AoP in preterm infants (born before 37 weeks). Cross-over studies were also included, provided sufficient data were available for analysis.
DATA COLLECTION AND ANALYSIS: We used the standard methods of Cochrane and Cochrane Neonatal, including independent assessment of risk of bias and extraction of data by at least two review authors. Discrepancies were resolved by involvement of a third author. We used the GRADE approach to assess the certainty of evidence for the following outcomes: 1) failed CPAP; 2) apnoea; 3) adverse effects of CPAP.
MAIN RESULTS: We included four single-centre trials conducted in Malaysia, Spain, Germany, and North America, involving 138 infants with a mean/median gestation of 26 to 28 weeks. Two studies were parallel-group RCTs and two were cross-over trials. None of the studies compared CPAP with supportive care. All trials compared one form of CPAP with another. Two compared a variable flow device with ventilator CPAP, one compared two different variable flow devices, and one compared a variable flow device with bubble CPAP. Interventions were administered for periods ranging between six and 48 hours, with pressures between 4 and 6 cm H2O. We assessed all trials as having a high risk of bias for blinding of participants and personnel, and two studies for blinding of outcome assessors. We found a high risk of a carry-over effect in two studies where the washout period was not adequately described, and a high risk of bias in a study that appeared to use an analysis method not generally accepted for cross-over studies. Comparison 1. CPAP and supportive care compared to supportive care alone We did not identify any study for inclusion in this comparison. Comparison 2. CPAP delivered by different types of devices 2a. Variable flow compared to ventilator CPAP Two studies were included in this comparison. We are very uncertain whether there is any difference in the incidence of failed CPAP, defined as the need for mechanical ventilation (risk ratio (RR) 0.16, 95% confidence interval (CI) 0.01 to 2.90; 1 study, 26 participants; very low-certainty). We are very uncertain whether there is any difference in the frequency of apnoea events (mean difference (MD) per four-hour interval -0.10, 95% CI -1.30 to 1.10; 1 study, 26 participants; very low-certainty). We are uncertain whether there is any difference in adverse events. Neurodevelopmental outcomes were not reported. 2b. Variable flow compared to bubble CPAP We included one study in this comparison, but it did not report our pre-specified outcomes. 2c. Infant Flow variable flow CPAP compared to Medijet variable flow CPAP We are very uncertain whether there is any difference in the incidence of failed CPAP (RR 2.62, 95% CI 0.91 to 7.53; 1 study, 80 participants; very low-certainty). The frequency of apnoea was not reported, and we do not know whether there is any difference in adverse events. Neurodevelopmental outcomes were not reported. Comparison 3. CPAP compared to mechanical ventilation We did not identify any studies for inclusion in this comparison.
AUTHORS' CONCLUSIONS: Due to the limited available evidence, we are very uncertain whether any CPAP device is more effective than other forms of supportive care, other CPAP devices, or mechanical ventilation for the prevention and treatment of AoP. The devices used in these studies included two types of variable flow CPAP device: bubble CPAP and ventilator CPAP. For each comparison, data were only available from a single study. There are theoretical reasons why these devices might have different effects on AoP, therefore further trials are indicated.