Duration of monitoring after cessation of oxygen therapy in infants with bronchiolitis

AIM

There is no evidence for how long bronchiolitis patients should be observed after coming off oxygen therapy and wide practice variation exists. We aimed to investigate whether it is safe to discharge bronchiolitis patients 4 h after cessation of oxygen therapy.

METHODS

A retrospective single-centre cohort study of 884 infants (n = 462 in 2018 vs. n = 422 in 2019) aged 0-24 months admitted with bronchiolitis in 2018 and 2019 was conducted after implementation of a bronchiolitis protocol recommending discharge home 4 h post-cessation of oxygen therapy in 2019. We compared the rate of readmissions and Clinical Reviews/Rapid Responses in the pre- and post-exposure cohorts.

RESULTS

There was a significant reduction in median (interquartile range (IQR)) time to discharge post oxygen cessation by 87 min (510 (370-1033) min versus 423 (273-904) min; P < 0.001) and in median (IQR) length of stay by 6.7 h (2.11 (1.54-2.97) days vs. 1.83 (1.17-2.71) days; P < 0.001). There was no significant difference between readmissions in 2018 compared to 2019 (0.6% vs. 1.4%; P = 0.317). In 2018, there were two Clinical Reviews and in 2019 there were two Rapid Responses post-cessation of oxygen. There were 89 patients discharged within 4 h of cessation of oxygen therapy (n = 18 in 2018 vs. n = 71 in 2019; P < 0.001) with no readmissions, Clinical Reviews or Rapid Responses in the 2019 cohort.

CONCLUSIONS

This study demonstrates that patients can be discharged 4 h after cessation of supplemental oxygen without increased risk of adverse events.

A Systematic Review of Clinical Practice Guidelines for Neonatal Abstinence Syndrome

BACKGROUND

The prevalence of neonatal abstinence syndrome is increasing, but the number and quality of clinical practice guidelines available are unknown. This systematic review aimed to identify, appraise and evaluate clinical practice guidelines for neonatal abstinence syndrome.

METHODS

A systematic search of databases and the grey literature was conducted between 1 June and 1 July 2022. Full-text guidelines published by national or state-wide institutions were included. The recommendations from each guideline were extracted. The AGREE-II instrument was used to assess guideline quality. Sufficient-quality scores were defined as >60 and good-quality scores were >80 for each domain of AGREE-II.

RESULTS

A total of 1703 records were identified, and 22 guidelines from the United States, Australia, Canada and the United Kingdom, published between 2012 to 2021, were included. The quality scores were low, with median scores of 37/100 for stakeholder involvement, 33/100 for methodology, 34/100 for applicability and 0 for editorial independence. Scope and purpose scored 72/100, and presentation scored 85/100. Sixteen (73%) guidelines did not meet the cut-offs for clinical use.

CONCLUSION

Many guidelines were of insufficient quality to guide clinical practice for neonatal abstinence syndrome. This emphasises the need for high-quality studies to inform clinical practice guidelines, improve care and reduce the risk of poor outcomes in these high-risk infants.

Determination of critical operational conditions favoring sulfide production from domestic wastewater treated by a sulfur-utilizing denitrification process

The aim of this study was to determine the critical operational conditions leading to the generation of sulfide in a domestic wastewater treated by a sulfur-utilizing denitrification process. The influence of various important parameters on the reduction of the sulfates present in denitrified domestic wastewaters to sulfide was studied. Experiments were carried out in batch mode with denitrified domestic wastewaters containing various amounts of both organic matter and sulfates. Preliminary results showed that aqueous sulfide was generated for DOC and sulfate contents higher than 56 mg/L and 371 mg/L, respectively, while DOC and sulfate contents of 77 mg/L and 412 mg/L, respectively, were required to allow the release of gaseous H₂S. Good correlations were also observed between gaseous sulfide production and the values of ORP and DOC, while the amounts of dissolved sulfide produced seemed to be correlated with the ORP values and the concentration of sulfates. Additional experiments were conducted using a Box-Behnken methodology to determine if the production of aqueous or gaseous sulfide can be predicted depending on the DOC (from 50 to 90 mg/L) and sulfate contents (from 160 to 380 mg/L) at various temperatures ranging from 5 to 25 °C. The highest sulfide generation (H₂S_(g) = 84.8 ppm and H₂S_(aq) = 2.42 mg/L) occurred at 25 °C with DOC and sulfate concentrations starting from 90 mg/L and 270 mg/L, respectively, indicating that the production of sulfides from denitrified domestic wastewaters required conditions not likely to occur at the effluent of a sulfur-based denitrification unit following secondary treatment.

Basal ganglia perfusion in the preterm infant during transition

BACKGROUND

The preterm brain is susceptible to changes in blood flow. Using power Doppler images, digital imaging techniques have been developed to measure the total amount of blood flow in a defined area, giving the index: fractional moving blood volume (FMBV). The aim of this study was to investigate temporal changes in basal ganglia perfusion during the transitional period after birth.

METHODS

Twenty-four preterm infants were examined with serial cranial ultrasounds at four time points during the first 48 h of life. FMBV was calculated using power Doppler images at each time point.

RESULTS

All infants had analyzable data and FMBV was successfully calculated at all time points. Twenty-three of the 24 infants had an increasing trend in FMBV over time. The median FMBV increased from 17% at 6 h to 25% at 48 h. One-way repeated measures ANOVA showed a significant increase in values at P < 0.001 at each of the four time points.

CONCLUSION

We have demonstrated changes in basal ganglia blood flow as the cerebral circulation adapts to extrauterine life. With further investigation, this technique may be useful in the assessment of preterm circulatory adaptation, either alone or in conjunction with other modes of evaluating cerebral blood flow.

Assessment of sulfide production risk in soil during the infiltration of domestic wastewater treated by a sulfur-utilizing denitrification process

This study aimed to determine the potential of sulfide generation during infiltration through soil of domestic wastewater treated by a sulfur-utilizing denitrification process. Three types of soil with different permeability rates (K s = 0.028, 0.0013, and 0.00015 cm/s) were investigated to evaluate the potential risk of sulfur generation during the infiltration of domestic wastewater treated by a sulfur-utilizing denitrification system. These soils were thoroughly characterized and tested to assess their capacity to be used as drainages for wastewaters. Experiments were conducted under two operating modes (saturated and unsaturated). Sulfate, sulfide, and chemical oxygen demand (COD) levels were determined over a period of 100 days. Despite the high concentration of sulfates (200 mg/L) under anaerobic conditions (ORP = -297 mV), no significant amount of sulfide was generated in the aqueous (<0.2 mg/L) or gaseous (<0.15 ppm) phases. Furthermore, the soil permeability did not have a noticeable effect on the infiltration of domestic wastewater treated by a sulfur-utilizing denitrification system due to low contents of organic matter (i.e., dissolved organic carbon, DOC). The autotrophic denitrification process used to treat the domestic wastewater allowed the reduction of the concentration of biochemical oxygen demand (BOD5) below 5 mg/L, of DOC below 7 mg/L, and of COD below 100 mg/L.

Spatiotemporal Image Correlation and Volumetric Impedance Indices in the Neonatal Brain: Proof of Concept and Preliminary Reproducibility

OBJECTIVES

Changes in tissue perfusion can be critically important in the vulnerable neonate, but they are very difficult to assess at the bedside. Spatiotemporal image correlation (STIC) sonography is an exciting concept that allows assessment of blood flow by rearranging and merging multiple 2-dimensional color images to create serial 3-dimensional images showing regional blood flow throughout the cardiac cycle. Variations in tissue blood flow may reflect tissue impedance and perfusion. The aim of this study was to demonstrate that it is possible to use STIC images to evaluate tissue impedance in the neonatal brain.

METHODS

Spatiotemporal image correlation data sets were acquired by cranial sonography in 19 neonates. Offline data analysis was performed by using virtual organ computer-aided analysis. With the use of STIC images from different phases of the cardiac cycle, impedance indices were calculated, based on maximum (systolic), minimum (diastolic), and mean virtual organ computer-aided analysis values, in the same way that resistive indices are calculated in 2-dimensional sonography.

RESULTS

Volumetric indices for tissue impedance were obtained for all neonates. Intraclass correlation coefficients (95% confidence intervals) for volumetric impedance indices were as follows: systolic/diastolic ratio, 0.793 (0.615-0.906); pulsatility index, 0.790 (0.609-0.905); and resistive index, 0.783 (0.598-0.901). Interclass correlation coefficients for image processing and analysis were as follows: systolic/diastolic ratio, 0.868 (0.692-0.947); pulsatility index, 0.904 (0.772-0.962); and resistive index, 0.914 (0.794-0.966).

CONCLUSIONS

This study shows that STIC data sets can be used to calculate volumetric impedance indices in the neonatal brain. Preliminary assessment shows that this technique appears reliable and allows evaluation of regional tissue impedance in the neonate.

Reference Ranges for Neonatal Basal Ganglia Perfusion as Measured by Fractional Moving Blood Volume

BACKGROUND

Regional changes in cerebral blood flow and perfusion are implicated in the pathogenesis of adverse neurological events that lead to death and severe disability in the newborn infant. The basal ganglia, in particular, are extremely sensitive to acute hypoxia in the perinatal period, but normal perfusion to this area is unknown.

OBJECTIVES

To establish a reference range for regional basal ganglia perfusion using fractional moving blood volume (FMBV) as an index.

METHODS

Head ultrasounds were performed on neonates from 25 to 41 weeks' gestation. Power Doppler images were obtained from a pre-specified coronal plane. FMBV was calculated offline after selecting the basal ganglia as a region of interest. The average of five calculations was considered to be representative of the regional perfusion for each neonate. The data were analysed, and a neonatal reference range was defined.

RESULTS

124 neonates were included in the study, and all had analysable data. The mean FMBV was 28.8% (±9.6) with a reference range defined as 10-48%. The mean FMBV for neonates <32 weeks', 32-35 weeks' and >35 weeks' gestation were 29.4% (±7.8), 29.2% (±11.0) and 27.4% (±9.7), respectively. Analysis of variance showed no significant difference between neonates based on gestation.

CONCLUSIONS

We have successfully used the index FMBV to define a reference range for perfusion in the basal ganglia. These data can be used as a reference for subsequent studies that evaluate basal ganglia perfusion in pathological conditions.

Identification of dichloroacetic acid degrading Cupriavidus bacteria in a drinking water distribution network model

AIMS

Bacterial community structure and composition of a drinking water network were assessed to better understand this ecosystem in relation to haloacetic acid (HAA) degradation and to identify new bacterial species having HAA degradation capacities.

METHODS AND RESULTS

Biofilm samples were collected from a model system, simulating the end of the drinking water distribution network and supplied with different concentrations of dichloroacetic and trichloroacetic acids at different periods over the course of a year. The samples were analysed by culturing, denaturing gradient gel electrophoresis (DGGE) and sequencing. Pipe diameter and HAA ratios did not impact the bacterial community profiles, but the season had a clear influence. Based on DGGE profiles, it appeared that a particular biomass has developed during the summer compared with the other seasons. Among the bacteria isolated in this study, those from genus Cupriavidus were able to degrade dichloroacetic acid. Moreover, these bacteria degrade dichloroacetic acid at 18°C but not at 10°C.

CONCLUSIONS

The microbial diversity evolved throughout the experiment, but the bacterial community was distinct during the summer. Results obtained on the capacity of Cupriavidus to degrade DCAA only at 18°C but not at 10°C indicate that water temperature is a major element affecting DCAA degradation and confirming observations made regarding season influence on HAA degradation in the drinking water distribution network.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first demonstration of the HAA biodegradation capacity of the genus Cupriavidus.

Metalworking fluids biodiversity characterization

AIMS

Hypersensitivity pneumonitis of machinists associated with metalworking fluids (MWF) was recently linked to Mycobacterium immunogenum. In addition to Mycobacterium, impacts of continuous and massive contact to other micro-organisms, such as Pseudomonas, were little studied. This report intended to quantify and characterize the microbial load of 44 in-use MWF.

METHODS AND RESULTS

The main biodiversity of MWF was assessed using cultural methods, quantitative PCR (qPCR) and denaturing gradient gel electrophoresis (DGGE). Total bacteria concentrations ranged from undetectable to 10(9) 16S rRNA gene copies per millilitre. Concentrations obtained by qPCR were up to five orders of magnitude higher than by culture, suggesting that MWF contamination is generally underestimated. Two samples showed high concentrations of Myco. immunogenum (1.55 x 10(7) and 3.49 x 10(5) 16S rRNA gene copies per millilitre). The overall biodiversity was low, as observed by culture and DGGE, and was comparable to data found in the literature. Pseudomonas pseudoalcaligenes was by far the main bacteria found in MWF samples (33 out of 44), followed by Ochrobactrum anthropi (32 out of 44). There was no significant relationship between the biodiversity profiles and the kind of MWF or equipment used, making it difficult to predict which micro-organisms will colonize each particular MWF.

CONCLUSIONS

Very high concentrations of bacteria were found in most MWF studied and limited biodiversities were observed. Many species of micro-organisms were retrieved from MWF samples, but they were mostly colonized by Pseudomonas pseudoalcaligenes and Ochrobactrum anthropi.

SIGNIFICANCE AND IMPACT OF THE STUDY

The major micro-organisms observed or recovered in this study from in-use MWF were present in very high concentrations, and thus further studies are needed to confirm their role in workers' respiratory disorders or health-related problems.

[Long-term follow-up of 128 children 13-14 years old, with birth weights of less than 2500 grams]

The records of 128 children, whose birth weight was below 2500 g and who were seen again at the ages of 13-14 years, were analyzed. Owing to the knowledge of the data of the last maternal menses in 115 cases, they could be separated in at-term dysmature, premature dysmature and true premature infants. The comparison between the 3 groups led to the following differences: On average, there is little difference between true premature infants and normal neonatal population, on both somatic and psychological points of view. Physical development is less satisfactory in at-term dysmature infants. If their median of I.Q. is close to normal, high intellectual abilities are rare and mental deficiency more frequent. In the physical, auditory, visual and psycho-motor fields, premature dysmature infants are the most underpriviliged.