Noninvasive Ventilation

Systematic Reviews and Randomized clinical trials have shown that the use of noninvasive ventilation (NIV) compared to invasive mechanical ventilation reduces the risk of bronchopulmonary dysplasia and or mortality. Most commonly used NIV modes include nasal continuous positive airway pressure, bi-phasic modes, such as, bi-level positive airway pressure, nasal intermittent positive pressure ventilation, high flow nasal cannula, noninvasive neurally adjusted ventilatory assist, and nasal high frequency ventilation are discussed in this review.

Economic and Clinical Impact of Using Human Milk-Derived Fortifier in Very Low Birth Weight Infants

Background: Implementation of exclusive human milk (EHM) feeding defined as mother's own milk or donor human milk fortified with human milk-derived fortifiers can place an economic burden on institutions. Methods: Retrospective study of very low birth weight (VLBW) infants before and after the implementation of EHM feedings. Neonatal demographics and clinical outcomes including necrotizing enterocolitis, severe retinopathy of prematurity, bronchopulmonary dysplasia, late-onset sepsis, days on parenteral nutrition (PN), and length-of-stay were collected. The net cost to the institution was estimated using published data. Results: Sixty-four infants in the pre-EHM period and 57 infants in the post-EHM period were enrolled. Net product acquisition cost in 2020 and 2021 was $884,823. The EHM feeding guideline led to a reduction in the mean length of stay and mean days of PN use by 6.3 and 6.8 days per infant, respectively. This led to a cost saving of $1,813,444 ($31,815 per infant). No significant difference in incidence of short-term morbidities was observed. Combining the cost avoidance from clinical outcomes, the estimated financial impact over 2 years excluding insurance reimbursement was an estimated $ 913,840 ($16,032 per infant). Conclusion: Implementation of EHM-based feeding in VLBW infants is a cost-effective option for neonatal intensive care units that can result in reduced length of stay and days on PN without adversely impacting short-term morbidities.

Effect of Maternal Preeclampsia on Cardiac Structure and Function in Very Low Birth Weight Infants

OBJECTIVE

 We aimed to determine whether exposure to severe maternal preeclampsia (PE) in very low birth weight (VLBW) infants is associated with hypertrophic cardiac changes and altered hemodynamics.

STUDY DESIGN

 Case-control study of VLBW infants born at Los Angeles General Medical Center from May 2015 to August 2023, who had an echocardiogram within the first 7 days of life. Cases were infants exposed to maternal PE and controls were infants not exposed to maternal PE matched by birth weight (BW) 1:1. Laboratory, placental pathology results, hemodynamic data and clinical outcomes were collected and compared between cases and control infants.

RESULTS

 A total of 43 cases matched by BW with control infants were studied. There were no significant anatomical cardiac changes by echocardiography between cases and control infants. Cases had significantly higher blood pressure within the first 72 hours of life and lower ejection fraction (EF), fractional shortening, and peak systolic flow velocity through their patent ductus arteriosus (PDA) within the first week of life. Cases were more likely to be smaller despite being born at a later gestational age (GA), as well as small for GA with placental weight less than 10th percentile compared to control infants.

CONCLUSION

 Our findings indicate that infants born to mothers with PE have higher systemic vascular resistance as evidenced by elevated blood pressure, and lower EF and shortening fraction and higher pulmonary vascular resistance as evidenced by lower peak flow velocity through the PDA. We did not observe hypertrophic cardiac changes in exposed infants. These findings should be considered in clinical decision-making during management of these infants.

KEY POINTS

· VLBW infants exposed to severe PE have higher rate of Small for gestational age and smaller placentas.. · VLBW infants exposed to severe PE have higher systemic vascular resistance during transitional period and lower EF and fractional shortening.. · VLBW infants exposed to severe PE have higher pulmonary vascular resistance..

Evaluation of the Puritan Bennett™ 980 Ventilator System Safety and Performance in the Real-World Setting

Purpose

Mechanical ventilation is a life-supporting intervention but is associated with known risks and complications. To improve the efficacy and safety profile of mechanical ventilation, manufacturers have developed advanced ventilator settings, modes, and alarm strategies to optimize ventilation for patient needs while avoiding complications. However, there is little real-world data published on the deployment of ventilator technology. The main objective of this study was to assess the clinical safety and performance of the Puritan Bennett™ 980 Ventilator System (PB980) using real-world clinical data collected from a diverse, global patient population.

Methods

This was a multi-center, post-market registry study that included nine sites: four in the United States of America, one in Europe, and four in China. Patients were enrolled into the registry if they were intended to be treated with a PB980. Data collection began at the start of ventilation and continued until extubation off the ventilator or up to seven days of ventilation, whichever occurred first. Subjects were divided by age into three categories: infants (0-365 days), pediatric (1-17 years), and adult (18 years and older). The primary outcome was device-related complication rate.

Results

Two-hundred-and-eleven subjects were enrolled (41 infants, 48 pediatric, and 122 adults). Sixteen deaths, unrelated to device deficiency, occurred during the data collection timeframe (relative frequency: 7.58, 95% CI: 4.40, 12.0). Only one device-related adverse event was reported (relative frequency: 0.47% 95% CI: 0.01%, 2.61%).

Conclusion

Ventilation by the PB980 was delivered safely in this multi-center observational study, which included a diverse sample of patients with broad ventilatory needs.

Common Clinical Scenarios of Systemic Hypertension in the NICU

Hypertension affects ∼1% to 3% of newborns in the NICU. However, the identification and management of hypertension can be challenging because of the lack of data-driven diagnostic criteria and management guidelines. In this review, we summarize the most recent approaches to diagnosis, evaluation, and treatment of hypertension in neonates and infants. We also identify common clinical conditions in neonates in whom hypertension occurs, such as renal vascular and parenchymal disease, bronchopulmonary dysplasia, and cardiac conditions, and address specific considerations for the evaluation and treatment of hypertension in those conditions. Finally, we discuss the importance of ongoing monitoring and long-term follow-up of infants diagnosed with hypertension.

Umbilical Cord Milking Versus Delayed Cord Clamping in Infants 28 to 32 Weeks: A Randomized Trial

OBJECTIVES

To determine whether rate of severe intraventricular hemorrhage (IVH) or death among preterm infants receiving placental transfusion with UCM is noninferior to delayed cord clamping (DCC).

METHODS

Noninferiority randomized controlled trial comparing UCM versus DCC in preterm infants born 28 to 32 weeks recruited between June 2017 through September 2022 from 19 university and private medical centers in 4 countries. The primary outcome was Grade III/IV IVH or death evaluated at a 1% noninferiority margin.

RESULTS

Among 1019 infants (UCM n = 511 and DCC n = 508), all completed the trial from birth through initial hospitalization (mean gestational age 31 weeks, 44% female). For the primary outcome, 7 of 511 (1.4%) infants randomized to UCM developed severe IVH or died compared to 7 of 508 (1.4%) infants randomized to DCC (rate difference 0.01%, 95% confidence interval: (-1.4% to 1.4%), P = .99).

CONCLUSIONS

In this randomized controlled trial of UCM versus DCC among preterm infants born between 28 and 32 weeks' gestation, there was no difference in the rates of severe IVH or death. UCM may be a safe alternative to DCC in premature infants born at 28 to 32 weeks who require resuscitation.

Effect of assessing velocity time integral at different locations across ventricular outflow tracts when calculating cardiac output in neonates

This study aims to evaluate the effect of assessing velocity time integral at different locations across ventricular outflow tracts for calculating cardiac output (CO) in neonates. Velocity time integral (VTI) and CO were measured at 3 different locations across right and left ventricular outflow tracts using transthoracic echocardiography in healthy term neonates without any major congenital heart disease. ANOVA with Bonferroni correction was used to determine the differences between the VTI and CO sampled at these three locations. Forty-one neonates met inclusion criteria with mean gestational age of 38.6 ± 1 weeks and mean birth weight of 3155 ± 463 g. The median hours after birth when echocardiography was obtained was 23 h (range 11-68 h after birth). Left CO were 121 ± 30 mL/kg/min, 155 ± 38 mL/kg/min, and 176 ± 36 mL/kg/min measured below the valve, hinges of the valve, and tip of the valve, respectively. Right CO were 197 ± 73 mL/kg/min, 270 ± 83 mL/kg/min, and 329 ± 104 mL/kg/min measured below the valve, hinges of the valve, and tip of the valve, respectively. A statistically significant difference (P < 0.001) was found in the VTI and CO measured at the 3 different locations across both left and right ventricular outflow tracts.     Conclusions: There is a significant difference in measurements of VTI and CO depending on the location of Doppler gate sampling across the ventricular outflow tracts. Consistency and precision in Doppler gate location are essential for measuring VTI and calculating CO while assessing changes in hemodynamic status in critically ill infants. What is Known: • Targeted Neonatal Echocardiography is increasingly applied to measure cardiac output in critically ill neonates and serial assessments are performed to assess the trend in changes in cardiac output. • Noninvasive measurement using velocity time integral to calculate cardiac output is commonly performed. However, location of Doppler sample gate to measure ventricular outflow tract velocity time integral is not consistent. What is New: • Statistically significant changes in measured velocity time integral and cardiac output are noted based on the location of Doppler gate sampling. • To monitor the cardiac output for trending, it is important to be consistent with regards to the location of the Doppler sample gate to assess changes in cardiac output in critically ill newborns.

Transient Hypoglycemia and Biochemical Differences in Infants Less Than 1,250 G at Birth Fed Human Milk with Human Milk-Derived Fortifier versus Cow Milk-Derived Fortifier

OBJECTIVE

 Fortification of human milk (HM) with either human milk-derived fortifier (HMDF) or cow milk-derived fortifier (CMDF) is important in preterm infants. The objective is to compare the incidence of hypoglycemia, and biochemical values in infants less than 1,250 g at birth fed HMDF versus CMDF.

STUDY DESIGN

 It is a retrospective cohort study on infants less than 1,250 g at birth who were fed with HMDF or CMDF. Hypoglycemia was defined as blood glucose (BG) level equal to or less than 60 mg/dL within 72 hours of full enteral feeds when off total parenteral nutrition and intravenous fluids.

RESULTS

 Ninety infants were enrolled (HMDF = 61, CMDF = 29). HMDF group had a higher rate of hypoglycemia (46 vs. 24%; p = 0.048) after achievement of full enteral feeding. The median minimum BG was lower (61 vs. 71; p ≤ 0.01), while blood urea nitrogen (12 vs. 6; p ≤ 0.01) and albumin (3.1 vs. 2.7; p ≤ 0.01) were higher in HMDF group compared with CMDF.

CONCLUSION

 At full enteral feedings in infants less than 1,250 g at birth, an HMDF diet may predispose to hypoglycemia needing intervention. Close monitoring of BG levels once off parenteral nutrition is recommended.

KEY POINTS

· Exclusive human milk (EHM) feeding results in better nutritional indices.. · EHM feeding at higher calorie/ounce improves growth.. · Blood glucose needs to be monitored when off TPN during EHM feeding..

Two-Year Outcomes After Minimally Invasive Surfactant Therapy in Preterm Infants: Follow-Up of the OPTIMIST-A Randomized Clinical Trial

Importance

The long-term effects of surfactant administration via a thin catheter (minimally invasive surfactant therapy [MIST]) in preterm infants with respiratory distress syndrome remain to be definitively clarified.

Objective

To examine the effect of MIST on death or neurodevelopmental disability (NDD) at 2 years' corrected age.

Design, Setting, and Participants

Follow-up study of a randomized clinical trial with blinding of clinicians and outcome assessors conducted in 33 tertiary-level neonatal intensive care units in 11 countries. The trial included 486 infants with a gestational age of 25 to 28 weeks supported with continuous positive airway pressure (CPAP). Collection of follow-up data at 2 years' corrected age was completed on December 9, 2022.

Interventions

Infants assigned to MIST (n = 242) received exogenous surfactant (200 mg/kg poractant alfa) via a thin catheter; those assigned to the control group (n = 244) received sham treatment.

Main Outcomes and Measures

The key secondary outcome of death or moderate to severe NDD was assessed at 2 years' corrected age. Other secondary outcomes included components of this composite outcome, as well as hospitalizations for respiratory illness and parent-reported wheezing or breathing difficulty in the first 2 years.

Results

Among the 486 infants randomized, 453 had follow-up data available (median gestation, 27.3 weeks; 228 females [50.3%]); data on the key secondary outcome were available in 434 infants. Death or NDD occurred in 78 infants (36.3%) in the MIST group and 79 (36.1%) in the control group (risk difference, 0% [95% CI, -7.6% to 7.7%]; relative risk [RR], 1.0 [95% CI, 0.81-1.24]); components of this outcome did not differ significantly between groups. Secondary respiratory outcomes favored the MIST group. Hospitalization with respiratory illness occurred in 49 infants (25.1%) in the MIST group vs 78 (38.2%) in the control group (RR, 0.66 [95% CI, 0.54-0.81]) and parent-reported wheezing or breathing difficulty in 73 (40.6%) vs 104 (53.6%), respectively (RR, 0.76 [95% CI, 0.63-0.90]).

Conclusions and Relevance

In this follow-up study of a randomized clinical trial of preterm infants with respiratory distress syndrome supported with CPAP, MIST compared with sham treatment did not reduce the incidence of death or NDD by 2 years of age. However, infants who received MIST had lower rates of adverse respiratory outcomes during their first 2 years of life.

Trial Registration

anzctr.org.au Identifier: ACTRN12611000916943.

Outcomes of patent foramen ovale greater than 3 mm at birth in extremely low birthweight infants

BACKGROUND

Foramen ovale (FO) is an obligate fetal shunt that typically resolves after birth, although patency throughout life is not uncommon. The natural history of patent FO (PFO) is known in term infants, but less is known about its course in extremely preterm infants. We describe the echocardiographic changes in FO size from birth to discharge in extremely low birth weight (ELBW) infants in this retrospective study.

METHODS

Cohort was divided based on size of FO at birth. Size of FO at discharge was measured and evaluated relative to postnatal weight gain. Demographics and clinical outcomes were compared between the two groups.

RESULTS

Of the 54 ELBW infants, 50 were born with FO less than 3 mm in diameter (small), and 4 were born with FO greater than 3 mm (large). Of small defects, the majority (44/50, 88%) did not increase in size with weight gain, and minority (6/50, 12%) increased in size, and three of these 6 patients, FO grew to be slightly larger than 3 mm. In contrast, all large defects (4 of 4, 100%) nearly doubled in size with postnatal growth. These 4 ELBW infants with enlargement of FO had a flap valve evident on echocardiogram obtained prior to discharge, and subsequently closed on outpatient follow-up echocardiograms, although time to resolution was variable (6 months - 3 years). One infant had presumptive resolution because of the presence of flap valve.

CONCLUSION

No maternal or neonatal demographic characteristics were predictive of FO enlargement, although, demonstrable flap valve on discharge echocardiogram correlated with resolution of FO on outpatient follow-up echocardiogram. Therefore, based on our data, we recommend that ELBW infants born with large FO should have echocardiographic re-evaluation of the atrial septal opening prior to discharge, to specify the presence of a flap valve or lack thereof, which is an important detail that can help a neonatologist determine the need for outpatient cardiac follow-up.

Transcutaneous bilirubin levels in extremely preterm infants less than 30 weeks gestation

OBJECTIVE

The primary objective of this study was to determine the relationship between transcutaneous bilirubin (TcB) levels and total serum bilirubin (TSB) levels in extremely preterm infants.

STUDY DESIGN

We conducted a prospective multicenter study of extremely preterm infants less than 30 weeks gestation in California. Difference between paired TcB and TSB values were compared based on gestational age, birth weight, maternal race/ethnicity, chronological age as well as during and after phototherapy.

RESULTS

TSB values ranged from 0 to 12.6 mg/dl and the TcB values ranged from 0 to 14.2 mg/dl. TSB was predicted with a high degree of accuracy at TSB = 2.37 + 0.54 (TcB) with r = 0.786. There was good correlation across gestational age, birth weight, race/ethnic, chronological age subgroups as well as during and after phototherapy.

CONCLUSION

Our study supports the use of TcB as a screening tool for monitoring jaundice in extremely preterm infants.

Twin Premature Infants With Riboflavin and Biotin Deficiency Presenting With Refractory Lactic Acidosis, Rash, and Multiorgan Failure During Prolonged Parenteral Nutrition

We are reporting monochorionic, diamniotic twin premature infants born at 25 weeks and 6 days gestation with riboflavin (vitamin B2) and biotin (vitamin B7) deficiency, while on prolonged total parenteral nutrition (TPN) during vitamin shortage. They presented initially with skin rash, lactic acidosis, and thrombocytopenia. Both twins progressed to severe respiratory failure, severe lactic acidosis, with refractory vasodilatory shock, pancytopenia, ischemic bowel injury, acute kidney injury, liver injury, and capillary leak syndrome leading to death of twin A. The surviving twin B was diagnosed with riboflavin and biotin deficiency that presented with abnormal metabolic work up suggestive of maple syrup urine disease, glutaric acidemia type 2, and X-linked adrenoleukodystrophy. Twin B was started on riboflavin and biotin supplementation at 41 days of life, with rapid improvement in clinical findings and laboratory abnormalities within days of starting biotin and riboflavin supplementation. He was discharged home in stable condition at 49 weeks of postmenstrual age.

A Review of User-Centred Design Methods for Designing a Portable Oil Spill Skimmer

Boom and skimmer are mechanical techniques in Oil Spill Response and Recovery (OSRR) that collect oil from the water surface. However, there are several drawbacks of using boom and skimmer, such as the oil could pass over the boom during strong wind and high tides. Moreover, the currently available oil skimmer designed by the engineers is heavy-duty; in consequence, it is ineffective in shallow water. Thus, there is a need to develop a portable oil spill skimmer to complement the current drawbacks. Several journals on the fabrication of the oil spill skimmer were reviewed. Findings from literature shows that the development of oil spill skimmer lacks user requirements when designing a portable oil spill skimmer. This article provides a systematic review of Kansei Engineering and the Analytical Hierarchy Process in the product development process. Therefore, Kansei Engineering and Analytical Hierarchy Process (AHP) can be incorporated in the early stage of designing a portable oil spill skimmer. This paper also includes the application of Kansei Engineering and AHP in design research articles. Findings from observed articles indicate a lack of design and development technologies relating to products for environmental protection; the AHP and Kansei Engineering application is somewhat lacking. Moreover, the fabrication of an oil spill skimmer focuses more on technical specifications and includes fewer user requirements. As a result, the characteristics such as ease of use, robustness, and safety cannot be evaluated. The AHP and Kansei Engineering methodology can be extended to the design and manufacture of products for environmental protection.

Evaluation of Correlation and Agreement between SpO2/FiO2 ratio and PaO2/FiO2 ratio in Neonates

Objectives This article evaluates correlation and agreement between oxygen saturation (SpO2)/fraction of inspired oxygen (FiO2) (SF) ratio and partial pressure of oxygen (PaO2)/FiO2 (PF) ratio. It also derives and validates predictive PF ratio from noninvasive SF ratio measurements for clinically relevant PF ratios and derives SF ratio equivalent of PF ratio cutoffs used to define acute lung injury (ALI, PF < 300) and acute respiratory distress syndrome (ARDS, PF < 200).

Methods Retrospective cohort study including neonates with respiratory failure over a 6-year study period. Correlation and agreement between PF ratio with SF ratio was analyzed by Pearson's correlation coefficient and Bland–Altman analysis. Generalized estimating equation was used to derive PF ratio from measured PF ratio and derive corresponding SF ratio for PF ratio cutoffs for ALI and ARDS.

Results A total of 1,019 paired measurements from 196 neonates with mean 28 (± 4.7) weeks' gestational age and 925 (± 1111) g birth weight were analyzed. Strong correlation was noted between SF ratio and PF ratio (r = 0.90). Derived PF ratios from regression (1/PF = –0.0004304 + 2.0897987/SF) showed strong accuracy measures for PF ratio cutoffs < 200 (area under the curve [AUC]: 0.85) and < 100 (AUC: 0.92) with good agreement. Equivalent SF ratio to define ALI was < 450, moderate ARDS was < 355, and severe ARDS was < 220 with strong accuracy measures (AUC > 0.81, 0.84, and 0.93, respectively).

Conclusion SF ratio correlated strongly with PF ratio with good agreement between derived PF ratio from noninvasive SpO2 source and measure PF ratio. Derived PF ratio may be useful to reliably assess severity of respiratory failure in neonates. Further studies are needed to validate SF ratio with clinical illness severity and outcomes.

The effect of cooking duration on radical scavenging properties of Hypsizygus tessellatus and Pleurotus ostreatus

Mushrooms are a popular ingredient in the human diet due to their flavour, nutritional values and functional properties, in particular, their antioxidant potential. Most mushrooms are consumed after cooking and the impact of cooking methods and durations on the antioxidant properties of various edible mushrooms have been reported. However, the reports on the effect of cooking on the antioxidant properties of Hypsizygus tessellatus (shimeji), a widely consumed mushroom in East Asia, are limited. Therefore, this study aimed to investigate the effect of cooking duration on the radical scavenging properties of H. tessellatus. Pleurotus ostreatus was included for comparison purposes. Mushroom samples were prepared raw, boiled in distilled water for 1 min, 3 mins and 5 mins, then blended and centrifuged to obtain mushroom extracts. The mushroom extracts were evaluated for their radical scavenging properties using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Results showed that 1-min cooked H. tessellatus extract exhibited the highest radical scavenging activity (76.6±2.14% DPPH scavenging activity) while extract boiled for 5 mins had the lowest radical scavenging activity (62.9±6.08% DPPH scavenging activity). Thus, cooking time has a significant effect on the radical scavenging activity of H. tessellatus extract. In conclusion, the effect of cooking on H. tessellatus and P. ostreatus can be both beneficial and disadvantageous depending on the duration.

Effectiveness of Simulation Training in Acquiring Echocardiography Skills among Neonatology Care Providers

OBJECTIVE

 The objective of this study was to test the hypothesis that simulation training improves echocardiography skills.

STUDY DESIGN

 In this prospective study, 43 participants (16 neonatologists, 26 neonatology fellows, and 1 nurse practitioner) were tested on the simulator after 4 hours of didactic sessions on topographical cardiac anatomy and standard echocardiographic views. Participants were given 20 minutes to obtain and save the standard views. After the simulation hands-on training for 8 hours over 3 days, they were tested again. Each image was scored from 0 to 3 based on the image quality. Pre- and postsimulator training data were compared using both automated and visual scoring methods.

RESULTS

 After the hands-on simulator training, the automated median (interquartile) score for the quality of acquired images increased from 36 (22, 43) to 55 (48, 58), p < 0.0001. The increase was similar using visual scoring. The number of views with acceptable or good image quality (scores of 2 or 3) increased from 11 (6, 16) to 20 (17, 21), p < 0.0001. The neonatology fellows and faculty, as well as those with or without prior echocardiography experience, demonstrated significant improvement.

CONCLUSIONS

 Echocardiography simulation is an effective tool in improving echocardiography skills among neonatology care providers.

KEY POINTS

· Simulation is effective in acquiring echocardiography skills among neonatology care providers.. · Simulation improves image acquisition in those with and without prior echocardiography experience.. · Effectiveness of simulation in retaining the acquired echocardiography skill should be investigated..

Bisindolylmaleimide Ligands Stabilize c-MYC G-Quadruplex DNA Structure and Downregulate Gene Expression

G-Quadruplex (G4) structures play a pivotal role in diverse biological functions, including essential processes, such as telomere maintenance and gene regulation. G4 structures formed in functional regions of genomes are actively pursued toward therapeutics and are targeted by small-molecule ligands that alter their structure and/or stability. Herein, we report the synthesis of bisindolylmaleimide-based (BIM) ligands, which preferentially stabilize parallel G4 structures of c-MYC and c-KIT oncogenes over the telomeric h-RAS1 G4 and duplex DNAs. The preferential stabilization of parallel G4s with BIM ligands is further validated by the DNA polymerase stop assay, where stop products were only observed for templates containing the c-MYC G4 sequence. Nuclear magnetic resonance (NMR) titration studies indicate that the lead ligand BIM-Pr1 forms a 2:1 complex with c-MYC G4 DNA with a K_D of 38 ± 5 μM. The BIM ligand stacks at the 5' and 3' quartets, with molecular modeling and dynamics studies supporting the proposed binding mode. The ligand is cytotoxic to HeLa cells and downregulates c-MYC gene expression. Collectively, the results present bisindolylmaleimide scaffolds as novel and powerful G4 targeting agents.

Late Preterm Infant With Postnatal Diagnosis of Renal Tubular Dysgenesis

A male infant born at 34 weeks' gestation presented with acute cardiorespiratory decompensation soon after birth followed by renal failure. Initial clinical course was complicated by ventilator requirement, bilateral pneumothoraces, and hypotension managed with multiple inotropes. Persistent renal failure with oliguria and renal ultrasound showing noncystic medical renal disease prompted further investigation. Whole-exome sequencing showed 2 pathologic mutations in the angiotensin-converting enzyme (ACE) gene, suggesting a diagnosis of renal tubular dysgenesis (RTD). Renal tubular dysgenesis is usually a fatal condition affecting the renin-angiotensin system with possible autosomal recessive inheritance. Acquired cases have been described in the setting of in utero exposure to medications such as nonsteroidal anti-inflammatory medications (NSAIDs) and ACE inhibitors. Renal tubular dysgenesis should be suspected in any neonate presenting with renal failure, refractory hypotension, ventilator requirement, hypoplastic lungs, renal ultrasound showing normal-sized echogenic noncystic kidneys with poor corticomedullary differentiation, and antenatal history significant for oligohydramnios. The overall prognosis of patients with RTD continues to improve with better ventilatory management and renal replacement therapies.

Effect of Minimally Invasive Surfactant Therapy vs Sham Treatment on Death or Bronchopulmonary Dysplasia in Preterm Infants With Respiratory Distress Syndrome: The OPTIMIST-A Randomized Clinical Trial

IMPORTANCE

The benefits of surfactant administration via a thin catheter (minimally invasive surfactant therapy [MIST]) in preterm infants with respiratory distress syndrome are uncertain.

OBJECTIVE

To examine the effect of selective application of MIST at a low fraction of inspired oxygen threshold on survival without bronchopulmonary dysplasia (BPD).

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial including 485 preterm infants with a gestational age of 25 to 28 weeks who were supported with continuous positive airway pressure (CPAP) and required a fraction of inspired oxygen of 0.30 or greater within 6 hours of birth. The trial was conducted at 33 tertiary-level neonatal intensive care units around the world, with blinding of the clinicians and outcome assessors. Enrollment took place between December 16, 2011, and March 26, 2020; follow-up was completed on December 2, 2020.

INTERVENTIONS

Infants were randomized to the MIST group (n = 241) and received exogenous surfactant (200 mg/kg of poractant alfa) via a thin catheter or to the control group (n = 244) and received a sham (control) treatment; CPAP was continued thereafter in both groups unless specified intubation criteria were met.

MAIN OUTCOMES AND MEASURES

The primary outcome was the composite of death or physiological BPD assessed at 36 weeks' postmenstrual age. The components of the primary outcome (death prior to 36 weeks' postmenstrual age and BPD at 36 weeks' postmenstrual age) also were considered separately.

RESULTS

Among the 485 infants randomized (median gestational age, 27.3 weeks; 241 [49.7%] female), all completed follow-up. Death or BPD occurred in 105 infants (43.6%) in the MIST group and 121 (49.6%) in the control group (risk difference [RD], -6.3% [95% CI, -14.2% to 1.6%]; relative risk [RR], 0.87 [95% CI, 0.74 to 1.03]; P = .10). Incidence of death before 36 weeks' postmenstrual age did not differ significantly between groups (24 [10.0%] in MIST vs 19 [7.8%] in control; RD, 2.1% [95% CI, -3.6% to 7.8%]; RR, 1.27 [95% CI, 0.63 to 2.57]; P = .51), but incidence of BPD in survivors to 36 weeks' postmenstrual age was lower in the MIST group (81/217 [37.3%] vs 102/225 [45.3%] in the control group; RD, -7.8% [95% CI, -14.9% to -0.7%]; RR, 0.83 [95% CI, 0.70 to 0.98]; P = .03). Serious adverse events occurred in 10.3% of infants in the MIST group and 11.1% in the control group.

CONCLUSIONS AND RELEVANCE

Among preterm infants with respiratory distress syndrome supported with CPAP, minimally invasive surfactant therapy compared with sham (control) treatment did not significantly reduce the incidence of the composite outcome of death or bronchopulmonary dysplasia at 36 weeks' postmenstrual age. However, given the statistical uncertainty reflected in the 95% CI, a clinically important effect cannot be excluded.

TRIAL REGISTRATION

anzctr.org.au Identifier: ACTRN12611000916943.

Association between blood carboxyhemoglobin level and bronchopulmonary dysplasia in extremely low birthweight infants

Carboxyhemoglobin (CO-Hb) can be endogenously formed in the presence of oxidative stress and may be elevated in inflammatory lung disease. There is lack of evidence of its relationship with the development of bronchopulmonary dysplasia (BPD) in extremely low birthweight (ELBW) infants. The objective of the study is to evaluate the relationship between blood CO-Hb levels in the first 14 days of life (DOL) in ELBW infants and the development of BPD at 36 weeks postmenstrual age (PMA). This is a retrospective cohort study of 58 ELBW infants born at LAC-USC Medical Center between June 2015 and and June 2019 who survived to 36 weeks PMA. CO-Hb values were collected daily from DOL 1 to DOL 14. BPD definition using the recent 2019 NICHD criteria was used. Multivariate logistic regression was performed to determine the association between blood CO-Hb levels and BPD. Receiver operator curve was used to evaluate the ability of the median fraction of inspired oxygen (FiO₂) level used at DOL 11-14 in discriminating absent to mild BPD versus moderate to severe BPD. 58 ELBW infants were included in the study. 24 (41%) were diagnosed with moderate to severe BPD, while 34 (59%) were diagnosed with no to mild BPD. Severity of BPD was fairly discriminated by FiO₂ at DOL 11-14, but not with CO-Hb levels at any point within the first 14 DOL. The role and mechanism of CO-Hb production in this population need to be further studied.

Maternal-to-Fetal Transmission of Syphilis and Congenital Syphilis

Between 2012 and 2018, rates of congenital syphilis increased by 291% in the United States. In 2018, the rate of congenital syphilis was the highest it has been since 1995. Given these concerning epidemiologic trends, this review seeks to summarize the maternal-to-fetal transmission of syphilis to ensure adequate care of affected mothers and their infants. It also serves as a call to reinvest public health resources and reestablish infrastructure to ensure reversal of this concerning trend to stop preventable perinatal deaths, associated morbidities, and long-term consequences of congenital syphilis.

Secret Key Generation Schemes for Physical Layer Security

Physical layer security (PLS) has evolved to be a pivotal technique in ensuring secure wireless communication. This paper presents a comprehensive analysis of the recent developments in physical layer secret key generation (PLSKG). The principle, procedure, techniques and performance metricesare investigated for PLSKG between a pair of users (PSKG) and for a group of users (GSKG). In this paper, a detailed comparison of the various parameters and techniques employed in different stages of key generation such as, channel probing, quantisation, encoding, information reconciliation (IR) and privacy amplification (PA) are provided. Apart from this, a comparison of bit disagreement rate, bit generation rate and approximate entropy is also presented. The work identifies PSKG and GSKG schemes which are practically realizable and also provides a discussion on the test bed employed for realising various PLSKG schemes. Moreover, a discussion on the research challenges in the area of PLSKG is also provided for future research.

Pericoronary adipose tissue attenuation in low-risk asymptomatic individuals, sex-differences and association with markers of cardiovascular disease

Funding Acknowledgements

Type of funding sources: None.

Introduction

Pericoronary adipose tissue (PCAT) attenuation by coronary computed tomography angiography (CCTA) is a marker of coronary inflammation and predicts clinical outcomes in symptomatic patients undergoing CCTA. Sex-differences in PCAT CT attenuation among asymptomatic individuals are not previously described.

Purpose

To evaluate PCAT CT attenuation according to sex and markers of cardiovascular disease (CVD).

Methods

Cross-sectional cohort study including asymptomatic individuals, 50- or 60-year of age, not taking any medicine and without known CVD or type-2 diabetes. At baseline and 5-year follow-up smoking habits, blood pressures and biochemistry (lipids, CRP, fibrinogen, D-dimer, t-PA, PAI-1, vWF) were recorded and Agatston Score measured. At follow-up, CCTA was achieved. Quantitative coronary plaque analysis was performed and PCAT CT attenuation within a radial distance of 3 mm from the outer vessel wall 10–50 mm distal to the origin of the right coronary artery measured. A validated PCAT CT attenuation threshold (high vs low risk) of -70.1 Hounsfield units was applied.

Results

Included were 123 participants (60 women). Independent of co-variation, PCAT CT attenuation (median, [IQR]) was lower in women (-71.0, [-77.2- -67.0]) vs men (-64.5, [-69.9- -57.4]), p &lt; 0.001. No associations between PCAT CT attenuation (high vs low) and risk factors of CVD, CAC or coronary plaque volumes were demonstrated (Table). Variations in blood pressures, biochemical markers and CAC over five years were not associated with PCAT CT attenuation.

Conclusion

In low-risk asymptomatic individuals, PCAT CT attenuation was lower in women compared to men, irrespective of markers of CVD.

Table. Patient characteristics stratified by PCAT CT attenuation PCAT CT attenuation ≤ -70.1 HU (n = 49) PCAT CT attenuation &gt; -70.1 HU (n = 74) p-value Risk factors Age65-years55-years 2623 3143 0.32 SexMenWomen 1534 4826 &lt;0.001 TobaccoNeverCurrent/previous 1732 3737 0.10 Systolic BP, mmHgDiastolic BP, mmHgTotal cholesterol, mmol/lLDL-cholesterol, mmol/lHDL-cholesterol, mmol/lTriglycerides, mmol/l 137 (17)76 (10)5.61 (0.92)3.50 (0.93)1.41 (0.30)1.65 (0.99 - 2.22) 136 (16)77 (10)5.42 (0.82)3.30 (0.82)1.45 (0.35)1.35 (1.03 - 2.11) 0.660.590.230.220.570.52 Biochemistry CRP, mg/lFibrinogen, μmol/lD-dimer, mg/lvWFt-PAPAI-1 1.16 (0.99 - 2.22)9.5 (8.5 - 10.7)0.40 (0.30 - 0.49)128 (102 - 154)7.1 (5.8 - 8.8)20.5 (16.2 - 31.8) 0.61 (0.30 - 1.14)9.0 (7.8 - 10.0)0.32 (0.24 - 0.47)116 (92 - 146)6.3 (5.1 - 8.8)20.3 (14.7 - 26.3) &lt;0.010.10&lt;0.050.110.200.34 Coronary plaque data Agatston ScoreTotal plaque volume, mm&sup3;NCP volume, mm&sup3;CP volume, mm&sup3;LD-NCP volume, mm&sup3; 1 (0 - 36)15.7 (0 - 143.3)0 (0 - 128.1)0 (0 - 14.6)0.5 (0 - 18.7) 8 (0 - 115)15.6 (0 - 268.2)13.5 (0 - 220.5)1.7 (0 - 31.7)1.8 (0 - 21.8) 0.300.450.490.360.74 Values are n (%), mean (SD) or median (IQR).Abbreviations: HU =Hounsfield unit; LDL =low-density lipoprotein; HDL =high-density lipoprotein; BP =blood pressure; CRP = c-reactive protein: vWF =von-Willebrand Factor; t-PA =tissue plasminogen activator; PAI-1 =plasminogen activator inhibitor -1; NCP =non-calcified plaque; CP =calcified plaque; LD-NCP =low-density non-calcified plaque.

Proportion of Retinopathy of Prematurity That Was Treated across Regions in the United States

OBJECTIVES

Retinopathy of prematurity (ROP) is the leading preventable cause of blindness in children worldwide. Major eye and visual problems are strongly linked to ROP requiring treatment. Objectives of the study are to: (1) evaluate the trends and regional differences in the proportion of treated ROP, (2) describe risk factors, and (3) examine if treated ROP predicts mortality.

STUDY DESIGN

Retrospective data analysis was conducted using the Kids' Inpatient Database from 1997 to 2012. ROP was categorized into treated ROP (requiring laser photocoagulation or surgical intervention) and nontreated ROP. Bivariate and multivariate logistic regression analyses were performed.

RESULTS

Out of 21,955,949 infants ≤ 12 months old, we identified 70,541 cases of ROP and 7,167 (10.2%) were treated. Over time, the proportion of treated ROP decreased (p = < 0.001). While extremely low birth weight infants cared for in the Midwest was associated with treated ROP (adjusted odds ratio [aOR] = 29.05; 95% confidence interval [CI]: 10.64-79.34), black race (aOR = 0.57; 95% CI: 0.51-0.64) care for in the birth hospital (aOR = 0.44; 95% CI: 0.41-0.48) was protective. Treated ROP was not associated with mortality.

CONCLUSION

The proportion of ROP that is surgically treated has decreased in the United States; however, there is variability among the different regions. Demographics and clinical practice may have contributed for this variability.

Synthesis of the Dynamical Properties of Feedback Loops in Bio-Pathways

Feedback loops regulate various biological functions such as oscillations, bistability, and robustness. They play a significant role in developmental signalling and failure of feedback can lead to disease. Systematic analysis of feedback loops could be useful in understanding their properties and biological effects. We propose here a method to automatically analyze feedback loops in bio-pathways and synthesize temporal logic properties which describe their dynamics. Starting with an ordinary differential equations (ODEs) based model of a bio-pathway, for a chosen feedback loop present in the pathway, we use a convolutional neural network to classify the behaviours of the key components of the feedback according to templates specified in bounded linear temporal logic (BLTL). Once a template has been identified, we instantiate the symbolic variables appearing in the template and synthesize properties using a parameter estimation procedure based on sequential hypothesis testing. We have applied this framework to a number of bio-pathway models and validated that the synthesized properties faithfully describe the behaviours of the feedback loops.

The emerging role of nebulization for maintenance treatment of chronic obstructive pulmonary disease at home

Inhalation therapy is the cornerstone of chronic obstructive pulmonary disease (COPD) management. However, for many COPD patients who are managed at home, nebulization therapy offers an effective alternative treatment and fulfills the gap of catering to the specific population of patients who are unable to use handheld inhaler devices appropriately. The present review highlights key aspects, namely selection of the right beneficiaries for home nebulization, available drugs in nebulized formulations for the treatment of COPD, and the importance of care, cleaning, and maintenance, which are prerequisites for ensuring successful nebulization therapy.

Bronchopulmonary dysplasia predicted at birth by artificial intelligence

Aim

To develop a fast bedside test for prediction and early targeted intervention of bronchopulmonary dysplasia (BPD) to improve the outcome.

Methods

In a multicentre study of preterm infants with gestational age 24‐31 weeks, clinical data present at birth were combined with spectral data of gastric aspirate samples taken at birth and analysed using artificial intelligence. The study was designed to develop an algorithm to predict development of BPD. The BPD definition used was the consensus definition of the US National Institutes of Health: Requirement of supplemental oxygen for at least 28 days with subsequent assessment at 36 weeks postmenstrual age.

Results

Twenty‐six (43%) of the 61 included infants developed BPD. Spectral data analysis of the gastric aspirates identified the most important wave numbers for classification and surfactant treatment, and birth weight and gestational age were the most important predictive clinical data. By combining these data, the resulting algorithm for early diagnosis of BPD had a sensitivity of 88% and a specificity of 91%.

Conclusion

A point‐of‐care test to predict subsequent development of BPD at birth has been developed using a new software algorithm allowing early targeted intervention of BPD which could improve the outcome.

Systemic to Pulmonary Collaterals in Extremely Low Birth Weight Infants: Incidence, Clinical Significance, and Hemodynamic Features

OBJECTIVE

This study aimed to determine the incidence of systemic to pulmonary collaterals (SPCs) in extremely low birth weight infants and to assess its clinical and hemodynamic significance beyond the neonatal period.

STUDY DESIGN

Retrospective cohort study was conducted on 61 infants with echocardiogram performed at the time of discharge to determine the presence of SPC and to measure the right and left ventricular outputs and left atrium to aortic ratio. We compared two groups: small or no SPC (Group 1) to moderate or large SPC (Group 2) on demographics, clinical outcomes, and echocardiographic parameters.

RESULTS

Sixty-one infants were included. The incidence of SPC was 57%; 21% of infants had moderate or large shunts and 31% had small SPC. Demographics, clinical outcomes, and echocardiographic parameters were not significantly different between small or no SPC and moderate to large SPC.

CONCLUSION

More than half of the infants had SPC. The size of the shunt did not affect the clinical outcomes nor the echocardiographic parameters measured. All infants had cardiac output above the normative mean.

Nasal High-Frequency Oscillatory Ventilation in Preterm Infants with Moderate Respiratory Distress Syndrome: A Multicenter Randomized Clinical Trial

OBJECTIVE

To determine whether nasal high-frequency oscillatory ventilation (NHFOV) as a primary mode of respiratory support as compared with nasal continuous airway pressure (NCPAP) will reduce the need for invasive mechanical ventilation in preterm infants (260/7-336/7 weeks of gestational age [GA]) with respiratory distress syndrome (RDS).

METHODS

This multicenter randomized controlled trial was conducted in 18 tertiary neonatal intensive care units in China. A total of 302 preterm infants born at a GA of 260/7-336/7 weeks with a diagnosis of RDS were randomly assigned to either the NCPAP (n = 150) or the NHFOV (n = 152) group. The primary outcome was the need for invasive mechanical ventilation during the first 7 days after birth.

RESULTS

Treatment failure occurred in 15 of 152 infants (9.9%) in the -NHFOV group and in 26 of 150 infants (17.3%) in the NCPAP group (95% CI of risk difference: -15.2 to 0.4, p = 0.06). In the subgroup analysis, NHFOV resulted in a significantly lower rate of treatment failure than did NCPAP in the strata of 26+0/7-29+6/7weeks of GA (11.9 vs. 32.4%, 95% CI of risk difference: -39.3 to -1.7, p = 0.03) and birth weight <1,500 g (10.4 vs. 29.6%, 95% CI of risk difference: -33.8 to -4.6, p = 0.01). The rate of thick secretions causing an airway obstruction was higher in the NHFOV group than in the NCPAP group (13.8 vs. 5.3%, 95% CI of risk difference: 1.9-15.1, p = 0.01). No significant differences in other secondary outcomes were found between the NHFOV and NCPAP groups.

CONCLUSIONS

NHFOV was not superior to NCPAP with regard to the primary outcome when applied as the primary respiratory support for RDS in infants between 26+0/7 and 33+6/7 weeks of GA. In the subgroup analysis, NHFOV seemed to improve effectiveness than NCPAP in preterm infants <30 weeks of GA.

Synthetic Surfactant CHF5633 Compared with Poractant Alfa in the Treatment of Neonatal Respiratory Distress Syndrome: A Multicenter, Double-Blind, Randomized, Controlled Clinical Trial

OBJECTIVE

To compare efficacy and safety of a new synthetic surfactant, CHF5633, enriched with surfactant proteins, SP-B and SP-C peptide analogues, with porcine surfactant, poractant alfa, for the treatment of respiratory distress syndrome in infants born preterm.

STUDY DESIGN

Neonates born preterm on respiratory support requiring fraction of inspired oxygen (FiO₂) ≥0.30 from 24^0/7 to 26^6/7 weeks and FiO₂ ≥0.35 from 27^0/7 to 29^6/7 weeks of gestation to maintain 88%-95% oxygen saturation were randomized to receive 200 mg/kg of CHF5633 or poractant alfa. If necessary, redosing was given at 100 mg/kg. Efficacy end points were oxygen requirement (FiO₂, respiratory severity score [FiO₂ × mean airway pressure]) in the first 24 hours, 7 and 28 days, discharge home, and/or 36 weeks of postmenstrual age; mortality and bronchopulmonary dysplasia at 28 days and 36 weeks of PMA. Adverse events and immunogenicity were monitored for safety.

RESULTS

Of the 123 randomized neonates, 113 were treated (56 and 57 in CHF5633 and poractant alfa groups, respectively). In both arms, FiO₂ and respiratory severity score decreased from baseline at all time points (P < .001) with no statistically significant differences between groups. Rescue surfactant use (19 [33.9%] vs 17 [29.8%]), bronchopulmonary dysplasia (31 [55.4%] and 32 [56.1%]), and mortality at day 28 (4 [7.1%] and 3 [5.3%]) were similar in the CHF5633 and poractant alfa groups, respectively. In 2 (3.4%) and 1 (1.7%) neonates, adverse drug reactions were reported in CHF5633 and poractant alfa groups, respectively. No immunogenicity was detected.

CONCLUSIONS

Treatment with CHF5633 showed similar efficacy and safety as poractant alfa in neonates born preterm with moderate-to-severe respiratory distress syndrome.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02452476.

Extremely Preterm Infant Born to a Mother With Severe COVID-19 Pneumonia

Little is known about the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on pregnant women, fetuses, and neonates, especially when the virus is contracted early in pregnancy. The literature is especially lacking on the effects of SARS-CoV-2 on extremely preterm (<28 weeks gestation) infants who have underdeveloped immune systems. We report the case of an extremely preterm, 25-week 5-days old infant, born to a mother with severe COVID-19 (coronavirus disease-2019) pneumonia. In this case, there is no evidence of vertical transmission of SARS-CoV-2 based on reverse transcription-polymerase chain reaction testing, despite extreme prematurity. However, it appears that severe maternal COVID-19 may have been associated with extremely preterm delivery, based on observed histologic chorioamnionitis. This is the first reported case of an extremely preterm infant born to a mother with severe COVID-19 pneumonia who required intubation, and was treated with hydroxychloroquine, azithromycin, remdesivir, tocilizumab, convalescent plasma, inhaled nitric oxide, and prone positioning for severe hypoxemic respiratory failure prior to and after delivery of this infant. The infant remains critically ill with severe respiratory failure on high-frequency ventilation, inotropic support, hydrocortisone for pressor-resistant hypotension, and inhaled nitric oxide for severe persistent pulmonary hypertension with a right to left shunt across the patent ductus arteriosus and foramen ovale. Pregnant women or women planning to get pregnant should take all precautions to minimize exposure to SARS-CoV-2 to decrease adverse perinatal outcomes.

Perinatal quality improvement bundle to decrease hypothermia in extremely low birthweight infants with birth weight less than 1000 g: single-center experience over 6 years

Normothermia (36.5°C–37. 5°C) at the time of admission to the neonatal intensive care unit (NICU) in extremely low birthweight (ELBW) infants (birth weight <1000 g) is associated with decreased morbidity and mortality, decreased length of stay and hospital costs. We designed a thermoregulation bundle to decrease hypothermia (<36.5°C) in ELBW infants with a multidisciplinary perinatal quality improvement initiative that included the following key interventions: dedicated delivery room (DR)/operating room (OR) for all preterm deliveries of ≤32 weeks with DR/OR temperature set 24/7 at 74°F by the hospital engineering staff, use of exothermic mattress, preheated radiant warmer set at 100% for heat prior to delivery, servo-controlled mode after the neonate is placed on the warmer, and use of plastic wrap, head cap and warm towels. A total of 200 ELBW infants were admitted to our NICU between January 1, 2014 and December 31, 2019. Hypothermia (<36.5°C) occurred in 2.5% of infants, normothermia (36.5°C–37.5°C) in 91% of infants and transitional hyperthermia (>37.5°C) in 6.5% of ELBW infants. No case of moderate hypothermia (32°C–36°C) was seen in our infants. Our target rate of less than 10% hypothermia was reached in ELBW infants over the last 2 years with no cases of moderate hypothermia in 6 years. Eliminating hypothermia among ELBW remains a challenge and requires team effort and continuous quality improvement efforts.

Pulmonary Venous Congestion and Pulmonary Hemorrhage in an Extremely Premature Neonate With a Large Patent Ductus Arteriosus and Closed Patent Foramen Ovale: A Case Report

We describe a case of an extremely low birthweight infant with a large patent ductus arteriosus and closed foramen ovale resulting in markedly increased pulmonary blood flow, pulmonary venous congestion, and pulmonary hemorrhage.

A Review on Non-invasive Respiratory Support for Management of Respiratory Distress in Extremely Preterm Infants

Majority of extremely preterm infants require positive pressure ventilatory support at the time of delivery or during the transitional period. Most of these infants present with respiratory distress (RD) and continue to require significant respiratory support in the neonatal intensive care unit (NICU). Bronchopulmonary dysplasia (BPD) remains as one of the major morbidities among survivors of the extremely preterm infants. BPD is associated with long-term adverse pulmonary and neurological outcomes. Invasive mechanical ventilation (IMV) and supplemental oxygen are two major risk factors for the development of BPD. Non-invasive ventilation (NIV) has been shown to decrease the need for IMV and reduce the risk of BPD when compared to IMV. This article reviews respiratory management with current NIV support strategies in extremely preterm infants both in delivery room as well as in the NICU and discusses the evidence to support commonly used NIV modes including nasal continuous positive airway pressure (NCPAP), nasal intermittent positive pressure ventilation (NIPPV), bi-level positive pressure (BI-PAP), high flow nasal cannula (HFNC), and newer NIV strategies currently being studied including, nasal high frequency ventilation (NHFV) and non-invasive neutrally adjusted ventilatory assist (NIV-NAVA). Randomized, clinical trials have shown that early NIPPV is superior to NCPAP to decrease the need for intubation and IMV in preterm infants with RD. It is also important to understand that selection of the device used to deliver NIPPV has a significant impact on its success. Ventilator generated NIPPV results in significantly lower rates of extubation failures when compared to Bi-PAP. Future studies should address synchronized NIPPV including NIV-NAVA and early rescue use of NHFV in the respiratory management of extremely preterm infants.

Effects of Patent Ductus Arteriosus on Organ Blood Flow in Infants Born Very Preterm: A Prospective Study with Serial Echocardiography

OBJECTIVE

To characterize the effects of a patent ductus arteriosus (PDA) on different organ blood flows in infants born preterm.

STUDY DESIGN

Infants born preterm at ≤30 weeks of gestational age had daily echocardiography and Doppler assessments of middle cerebral artery, celiac artery, superior mesenteric (SMA), and renal arteries (RA) during the first postnatal week. Abnormal organ blood flow was defined as either reverse or absent diastolic flow, abnormally low mean or systolic velocities, or abnormally high pulsatility or resistance index.

RESULTS

Twenty-five infants born very preterm (gestational age 27.0 ± 2.1 weeks) were enrolled. PDA presence at time of measurement increased the risk of abnormal organ blood flows (39% vs 8%, P < .001). Ductal diameter and left atrium-to-aortic root (LA/Ao) ratio correlated positively with resistance index (celiac artery, SMA, RA), and negatively with mean velocity (ductal diameter: SMA, RA; LA/Ao ratio: RA). A PDA >2.0 mm, LA/Ao ratio >1.4, and their combination were associated with 8.0 (95% CI 1.6-39.4)-, 6.7 (1.3-34.7)-, and 38.2 (3.2-455.5)-fold increase in risk of abnormal organ blood flow index, respectively. Abnormal descending aorta flow was detected in only 2% of measurements.

CONCLUSIONS

Ductal size >2.0 mm and LA/Ao >1.4, especially in combination, are associated with a greater risk of abnormal organ blood flows. We suggest that Doppler assessment of the renal and superior mesenteric arteries are more likely to detect systemic hypoperfusion than the descending aorta.

Consumer Practices and Risk Factors that Predispose to Premature Browning in Cooked Ground Beef

Premature browning is a condition in which cooked ground beef patties turn brown before the USDA recommended temperature of 71°C. This presents a potential food safety concern, as consumers may be eating undercooked meat. Although various intrinsic and extrinsic factors contribute to premature browning, the current knowledge indicates that the myoglobin form present within the interior of patties has a significant influence on cooked color. The objective of the study was to determine the consumer practices of cooking, methods to determine doneness, and type of packaging of their purchased ground beef. The data utilized in this study came from Food Demand Survey (FooDS), which tracks consumer preferences, food expenditures, price expectations, and awareness and concern for a variety of food issues. The sample size of FooDS on-line survey for this study was 1,030. The survey questions consisted of doneness of patties, cooking time, and packaging type of patties. Pictures of different packaging types such as a tray, vacuum package, film wrapped, butcher wrapped paper, frozen patties, and chub were also included. Approximately 67% of respondents indicated that they determine the doneness of ground beef patties by visual observation, 18% identify the doneness by a certain length of time for cooking, and 13.5% use a meat thermometer. Interestingly, 69% of respondents noted that they like a brown interior color of cooked patties. If the patties were prone to premature browning, the chances of consuming undercooked patties are higher. Only 5.7% of people bought patties packaged in a vacuum, while 60% of respondents bought patties packaged in film wrapped or in a tray. Even after 20 yr of attempt by the USDA to educate consumers about safe cooking, the current practices increase the likelihood of premature browning and food safety concerns.

Characterization of the Cofactors Involved in Non-Enzymatic Metmyoglobin Reduction In Vitro

ObjectivesConsumers’ meat purchasing decisions are strongly influenced by color. Myoglobin is the primary meat pigment that contributes to meat color. Myoglobin consists of an iron-containing heme ring and amino acids in the form of globin chains. Both the state of the heme iron and the type of ligand affects meat color. The consumer-preferred bright cherry-red color oxymyoglobin is formed when the iron is in the ferrous state and oxygen bind to the heme. The oxidation of oxymyoglobin or deoxymyoglobin results in the formation of the brown color, ferric metmyoglobin. Predominant metmyoglobin accumulation negatively impacts consumer purchasing choices. Although muscle type and pre- and post-harvest factors can influence meat discoloration, meat has an inherent ability to reduce metmyoglobin through enzymatic pathways, mitochondria-mediated pathways, and non-enzymatic mechanisms. In the enzymatic pathway, an electron from NADH is transferred to metmyoglobin by an enzyme and an electron carrier; while in mitochondria-mediated pathway, an electron from the electron-transport chain is transferred via cytochromes. Previous research speculated the role of non-enzymatic pathway in meat color; however, limited studies have characterized the cofactors present in a meat system. The objectives of this study were to characterize cofactors in non-enzymatic metmyoglobin reduction and determine the effect of storage temperature and postmortem muscle pH in-vitro.Materials and MethodsPurified equine metmyoglobin was reduced in the presence of combinations of electron carriers and donors. Methylene blue and cytochrome c were evaluated as the electron carriers, and NADH and ascorbate were considered as the electron donors. The cofactors were held at 4 and 25°C to determine temperature effects on the reduction of metmyoglobin, and the same cofactor combinations were evaluated at pH of 5.2, 5.6, 6.0, and 6.4 to reflect postmortem muscle pH. Spectrophotometry was utilized to monitor the rates of metmyoglobin reduction. The experiments were replicated five times, and the data were analyzed using the Mixed Procedure of SAS.ResultsThe results indicated that methylene blue was a significantly more effective electron carrier than cytochrome c with both electron donors, ascorbate and NADH. EDTA had no impact on the non-enzymatic metmyoglobin reducing the ability of methylene blue (P = 0.91). Temperature and pH had cofactor specific effects on the non-enzymatic reduction of metmyoglobin. Lower temperature resulted in an increased non-enzymatic metmyoglobin reduction for methylene blue regardless of electron donor (ascorbate, P = 0.03, NADH, P = 0.04). As pH increased, the non-enzymatic metmyoglobin reducing activity reduced significantly in the presence of NADH and methylene blue.ConclusionIn conclusion, the characteristics of the cofactors at specific temperatures and pH impacted the non-enzymatic reduction of metmyoglobin. Further, current in vitro research indicated that non-enzymatic metmyoglobin reduction is possible at lower temperature and meat pH.

Differential Protein Abundance in Dark-Cutting and Normal-pH Beef

ObjectivesDark-cutting beef is a meat quality defect in which meat does not display the marketable bright-red color. Although previous studies have indicated that the ultimate pH of dark-cutting beef is greater than normal, the mechanistic basis for the occurrence is not clear. Various mitochondrial and glycolytic enzymes/proteins are involved in muscle metabolism and lowering of pH. However, limited knowledge is currently available on the muscle protein profile differences between dark-cutting and normal-pH beef. The objective of the current study was to identify proteins related to the development of the dark-cutting condition by comparing the protein expression differences between dark-cutting and normal-pH beef.Materials and MethodsDark-cutting and normal-pH beef samples were collected from six (n = 6) different animals after slaughter. Tissue samples (0.5 g) were digested in 5 mL of lysis buffer. Tissue lysates were homogenized, boiled, sonicated using a bioruptor and centrifuged at 10,000 g for 10 min. Samples were digested with trypsin/Lys-C overnight at 37°C, after which additional 2 µg/mL of protease was added and digestion was continued for another 8h. The resulting trypsinolytic peptides were acidified to 1% trifluoroacetic acid and purified by solid phase extraction with C18 affinity media. Protein expression profiles of both dark-cutting and normal-pH beef samples were determined using LC-MS/MS mass spectrometry-based proteomics. Collected raw data instrument files were searched against a bovine proteome database of 23,968 bovine proteome sequences using MaxQuant (V.1.5.3.8). Differential protein expression analysis was done in Perseus (V.1.5.1.3). Ingenuity pathway analysis (IPA) was utilized to determine the significant pathways of the differentially expressed proteins in dark-cutting and normal-pH beef. Gene ontology enrichment pathway analysis was performed to determine the main functions of the differentially expressed proteins in dark-cutting and normal-pH beef identified in our samples.ResultsMass spectrometry analysis identified 1148 proteins, and 97 of these proteins were differentially expressed between normal-pH and dark-cutting beef (P < 0.05). Fold change of 1.5 was observed for 29 proteins. Dark-cutting beef had 19 abundant proteins, while normal-pH beef had 10 abundant proteins. The majority of the upregulated proteins in dark-cutting beef were involved in mitochondrial functioning and metabolism, while the majority of the downregulated proteins were important in glycogen degradation, calcium signaling, α-adrenergic signaling, n-NOS-signaling and the proteasome pathways.ConclusionThe results identify new protein biomarkers associated with dark-cutting and suggest new mechanistic explanations for the dark-cutting phenotype.

Effect of Temperature on Oxymyoglobin and Metmyoglobin Denaturation Properties

ObjectivesPremature browning is a condition where the interior of patty/steak will appears fully cooked before the temperature necessary to kill foodborne pathogens is reached. Previous research reported that approximately 50% of ground beef retailed in the US is susceptible to premature browning. Myoglobin form present in the interior of steak or patties determines the cooked color appearance. Although previous studies noted that myoglobin denaturation is primarily responsible for the cooked color appearance, limited knowledge is currently available about the effect of temperature on oxymyoglobin and metmyoglobin denaturation properties. The objective of the current study was to determine the effects of myoglobin forms on thermal stability using circular dichroism spectroscopy.Materials and MethodsOxymyoglobin and metmyoglobin solutions at pH 5.6 in 50 mM sodium phosphate buffer were incubated in a continuous heat increment water bath for 10 min. At specific temperature points (65, 71, 73, and 76°C), myoglobin denaturation was determined by changes in myoglobin concentration and by protein unfolding (fluorescence and absorbance) methods. The myoglobin thermal stability was also determined by circular dichroism spectroscopy. Changes in secondary protein structure were determined every 2°C from 52 to 92°C. The data were analyzed as completely randomized using the Mixed Procedure of SAS. A significance level of 0.05 was used to determine differences between means.ResultsOxymyoglobin had greater (p < 0.05) unfolding (as indicated by absorbance changes) than metmyoglobin at all temperatures. However, at 65, 71, and 73°C there were no differences (p > 0.05) in fluorescence intensities between myoglobin forms. Circular dichroism spectroscopy indicates that oxymyoglobin is more heat labile than metmyoglobin.ConclusionThe results indicate that oxymyoglobin had greater denaturation and unfolding than metmyoglobin. Use of appropriate myoglobin denaturation quantification technique will help characterize premature browning.

Comparison of Oxidizing Solutions in the Evaluation of Metmyoglobin Reducing Activity in Dark-Cutting Beef

ObjectivesMetmyoglobin reducing activity (MRA) is an inherent muscle biochemical property that can influence color stability. Hence, MRA is used in color research to better understand meat color changes. A greater postmortem muscle pH can affect inherent biochemical properties, including the conventional methodologies to determine MRA. The MRA methodology described in the American Meat Science Association Color Guide utilize changes in nitric oxide induced-metmyoglobin level pre- and post-incubation. However, a greater muscle pH can limit initial metmyoglobin formation. Hence, the methodology discussed in the AMSA color guide may not provide accurate results. Therefore, the objectives of this research were to compare different conditions to induce initial metmyoglobin formation.Materials and MethodsIn the first objective, normal-pH and dark-cutting steaks were dipped in 0.3%s (level recommended in the AMSA color guide) and 1% nitrite solution to induce metmyoglobin formation. Metmyoglobin formed steaks were blotted dry, vacuum packaged, and incubated at 30°C to induce metmyoglobin reduction. In the second experiment, 1% ferricyanide solution was used as an oxidizing agent. The methodology used in objective 1 was used to measure MRA. The experiments were replicated three times and the data were analyzed using the Mixed Procedure of SAS.ResultsThere was no effect (P > 0.05) of nitrite concentration on MRA of dark-cutting beef. However, when 1% ferricyanide was used as an oxidizing agent, initial metmyoglobin was more (P < 0.05) in dark-cutting beef compared with 0.3% sodium nitrite solution.ConclusionThe results suggest that the use of a strong oxidizing agent can impart more metmyoglobin formation in high-pH/dark-cutting beef.

Effects of Finishing Diet and Packaging on Longissimus Dorsi Color

ObjectivesMeat color is extremely influential in purchasing decisions as consumers associate a bright-red color with freshness. The type of finishing diet can influence beef color. Previous studies have shown that grass-finished cattle have darker muscle color than grain-finished cattle. With the use of modified atmospheric packaging (MAP), beef purveyors are able to vary the gas compositions within a package and enhance beef color. However, limited studies have determined the effects of modified atmospheric packaging on grass-finished beef color. The objective of this study was to determine how finishing diet and packaging type affects the color of the longissimus dorsi (LD) muscle.Materials and MethodsDuring the stocker period, all of the cattle were on a forage diet. Cattle were then randomly assigned to either a conventional grain-based diet or an alfalfa pasture diet for finishing. Both conventionally and pasture-finished cattle were fed for 91 d. Cattle were slaughtered on the same day at a commercial beef processing facility under normal conditions and chilled for approximately 30 h. After grading, one strip loin from each carcass was collected and transported to Oklahoma State University. At 11 d postmortem, one steak (n = 60) from each strip loin was vacuum packaged and randomly assigned to display. Those steaks were then randomly assigned to PVC, HiOx-MAP (80% oxygen and 20% carbon dioxide), or CO-MAP (0.4% carbon monoxide, 69.5% nitrogen, and 30% carbon dioxide) packaging and were displayed under retail conditions for 5 d. Muscle darkening (MD), muscle color (MC), and surface discoloration (SD) were all analyzed by a trained panel (n = 6). MD was evaluated only on d 0 and MC and SD were scored once every 24 h for 0, 1, 2, 3, and 4 d. Lipid oxidation was measured by thiobarbituric acid reactive substances (TBARS) assay on d 4. Data were analyzed using the Mixed Procedure of SAS.ResultsThere was a significant display day by finishing diet by packaging interaction (P < 0.05) for muscle color and surface discoloration. There was also a significant finishing diet by packaging interaction (P < 0.05) for muscle darkening. Steaks packaged in HiOx-MAP remained the most stable in color and the brightest cherry-red colored throughout display time (P < 0.05) compared with other packaging types. PVC was the most discolored (P < 0.05) on d 3 and 4 when compared to HiOx-MAP and CO-MAP with the grain-finished PVC packaged steaks showing the most discoloration on d 4. Pasture-finished steaks packaged in CO-MAP displayed the darkest colored muscle (P < 0.05) on d 0. Steaks packaged in PVC had a higher amount of lipid oxidation (P < 0.05) compared with other packaging types.ConclusionThese results indicate that HiOx-MAP more effectively maintains the desired beef color of bright cherry-red for pasture-finished beef. The results also indicate that the use of appropriate packaging type can minimize the losses due to discoloration of steaks from either grain or grass-finished beef.

The Effect of Modified Atmospheric Packaging on Beef Color Sensory Characteristics of Different Muscle pH Categories

ObjectivesAny deviation from the bright-red color of beef can lead to discounted price or consumer rejection. Fresh beef lean color is influenced by pH. Various packaging techniques have been developed to enhance the lean color of beef steaks. Therefore, the objective of the current study was to evaluate the effects of modified atmospheric packaging on three different beef muscle pH categories.Materials and MethodsThe three categories evaluated for this study were: Normal (pH = 5.57 ± 0.1; N-pH), Moderately high (pH = 5.70 ± 0.09; M-pH), and High (pH = 6.39 ± 0.03; H-pH). The pH was taken on the carcass, at the 12th and 13th rib interface within 72 h of harvest at a commercial beef processing plant. Strip loins were fabricated from each carcass (n = 12) and sent to Oklahoma State University for further analysis. Strip loins were then cut into 2.54 cm steaks and randomly assigned to 1 of 3 packaging treatments: polyvinyl chloride overwrap (PVC), carbon monoxide modified atmosphere packaging (CO-MAP; 0.4% CO, 69.6% N, and 30% CO2) and high-oxygen modified atmospheric packaging (HiOx-MAP; 80% O2, and 20% CO2). Visual color measurements for muscle color (MC; (1 = extremely bright cherry-red and 7 = extremely dark red), and surface discoloration (SD; 1 = no discoloration [0%] and 7 = extensive discoloration [81–100%]) were recorded on d 2, 4, and 6 of retail display by a trained panel. Data were analyzed using the Mixed Procedure of SAS.ResultsFor all pH treatments, PVC packaging possessed the darkest muscle color (P < 0.05) score compared to CO- and HiOx-MAP. When comparing N-pH, M-pH, and H-pH values, CO-MAP had approximately a 27.3%, 22.2%, and 25.3% improvement in muscle color, indicating a brighter lean color compared to PVC. Additionally, HiOx-MAP had approximately a 10.9%, 17.4%, and 16.5% improvement in muscle color score for N-pH, M-pH, and H-pH, respectively. When packaging steaks in either CO- or HiOx-MAP there was no significant difference (P > 0.05) between d 4 and 6 of retail display for muscle color. However, there was a significant (P < 0.05) darkening in muscle color for steaks packaged in PVC from d 4 to 6 of retail display. By the fourth d of retail, N-pH steaks packaged in PVC had 38.3% and 39.0% greater (P < 0.05) surface discoloration than CO- and HiOx-MAP, respectively.ConclusionThese results suggest that packaging steaks of different pH categories in CO- or HiOx-MAP can improve the surface color compared to PVC packaging.