Exploring pulmonary distribution of intratracheally instilled liquid foams in excised porcine lungs

The applicability of inhalation therapy to some severe pulmonary conditions is often compromised by limited delivery rates (i.e. total dose) and low deposition efficiencies in the respiratory tract, most notably in the deep pulmonary acinar airways. To circumvent such limitations, alternative therapeutic techniques have relied for instance on intratracheal liquid instillations for the delivery of high-dose therapies. Yet, a longstanding mechanistic challenge with such latter methods lies in delivering solutions homogeneously across the whole lungs, despite an inherent tendency of non-uniform spreading driven mainly by gravitational effects. Here, we hypothesize that the pulmonary distribution of instilled liquid solutions can be meaningfully improved by foaming the solution prior to its instillation, owing to the increased volume and the reduced gravitational bias of foams. As a proof-of-concept, we show in excised adult porcine lungs that liquid foams can lead to significant improvement in homogenous pulmonary distributions compared with traditional liquid instillations. Our ex-vivo results suggest that liquid foams can potentially offer an attractive novel pulmonary delivery modality with applications for high-dose regimens of respiratory therapeutics.

Group B Streptococcus real-time PCR may potentially reduce intrapartum maternal antibiotic treatment

BACKGROUND

Protocols for preventing early-onset group B streptococcal (GBS) neonatal infection may result in unnecessary antibiotics administration. Real-time polymerase chain reaction (PCR) can provide a result within 30-60 min and has been found to be specific and sensitive for defining intrapartum GBS status.

OBJECTIVE

To evaluate whether implementation of GBS fast real-time PCR to all women who require GBS prophylaxis may reduce the use of maternal prophylactic antibiotics.

METHODS

This prospective cohort study included women admitted to a single delivery ward who required prophylactic antibiotics either due to a positive antepartum GBS culture screening performed at 35-37 weeks or due to an unknown GBS status with an intrapartum risk factor. All the women were tested by a double vaginal swab (real-time PCR and culture) as soon as it became apparent, they required antibiotic prophylaxis and prior to its administration.

RESULTS

Between May 2019 and August 2020, 303 women met eligibility criteria and were enrolled, but four were excluded from the analysis due to failed culture or PCR tests. Of 299 women included in the study, 208 (69.5%) and 180 (60.2%) women, showed no evidence of GBS on intrapartum culture or PCR, respectively. Of 89 GBS antepartum carriers, 43 (48.3%) and 32 (35.9%) had negative intrapartum culture and PCR results, respectively. Of the 210 women with risk factors, 165 (78.5%) were culture negative and 148 (70.4%) had a negative PCR. Using intrapartum culture as the gold standard, intrapartum GBS real-time PCR was found to have a sensitivity of 97.8% (95% confidence interval [CI] 92.3, 99.7) and a specificity of 85.6% (95% CI 80.1, 90.1).

CONCLUSIONS

Compared with antepartum universal culture screening or intrapartum risk-factor assessment, the need for maternal antibiotic treatment may be substantially reduced by implementation of intrapartum GBS real-time PCR, without compromising the sensitivity of GBS detection.

Expect the Unexpected-First Case of Congenital Rubella Syndrome in Israel in 20 Years: A Case Report

Congenital rubella syndrome (CRS) is a devastating condition associated with significant morbidity. Due to universal vaccination programs, it is currently a rare condition, especially in developed countries. We report an infant born in Israel to a foreign worker from the Philippines who presented with a blueberry muffin rash immediately after birth. Initial workup revealed sonographic brain anomalies, abnormal hearing tests, and a patent ductus arteriosus. CRS was subsequently confirmed by laboratory diagnosis. Rubella virus genotype 1E was detected in the infant's nasopharyngeal swab and urine samples. This was the first case of CRS in Israel in 20 years, emphasizing the need to "think outside the box" when dealing with infants of mothers who are foreign workers, refugees, or visitors of foreign relatives, in which rubella immune status is unknown. Additionally, public health authorities should consider the routine assessment of rubella immunity status of foreign workers in order to avoid such tragic, preventable diseases. We present a case of congenital rubella syndrome - rarely seen in developed countries. This emphasis the need to "think out of the box" when dealing with infants of mothers who come from countries in which the vaccination program is not well established.

Ventilation‐induced epithelial injury drives biological onset of lung trauma in vitro and is mitigated with prophylactic anti‐inflammatory therapeutics

Mortality rates among patients suffering from acute respiratory failure remain perplexingly high despite the maintenance of blood oxygen homeostasis during ventilatory support. The biotrauma hypothesis advocates that mechanical forces from invasive ventilation trigger immunological mediators that spread systemically. Yet, how these forces elicit an immune response remains unclear. Here, a biomimetic in vitro three‐dimensional (3D) upper airways model allows to recapitulate lung injury and immune responses induced during invasive mechanical ventilation in neonates. Under such ventilatory support, flow‐induced stresses injure the bronchial epithelium of the intubated airways model and directly modulate epithelial cell inflammatory cytokine secretion associated with pulmonary injury. Fluorescence microscopy and biochemical analyses reveal site‐specific susceptibility to epithelial erosion in airways from jet‐flow impaction and are linked to increases in cell apoptosis and modulated secretions of cytokines IL‐6, ‐8, and ‐10. In an effort to mitigate the onset of biotrauma, prophylactic pharmacological treatment with Montelukast, a leukotriene receptor antagonist, reduces apoptosis and pro‐inflammatory signaling during invasive ventilation of the in vitro model. This 3D airway platform points to a previously overlooked origin of lung injury and showcases translational opportunities in preclinical pulmonary research toward protective therapies and improved protocols for patient care.

Teaching During the COVID-19 Pandemic: The Experience of the Faculty of Medicine at the Technion-Israel Institute of Technology

BACKGROUND

The coronavirus disease-2019 (COVID-19) pandemic forced drastic changes in all layers of life. Social distancing and lockdown drove the educational system to uncharted territories at an accelerated pace, leaving educators little time to adjust.

OBJECTIVES

To describe changes in teaching during the first phase of the COVID-19 pandemic.

METHODS

We described the steps implemented at the Technion-Israel Institute of Technology Faculty of Medicine during the initial 4 months of the COVID-19 pandemic to preserve teaching and the academic ecosystem.

RESULTS

Several established methodologies, such as the flipped classroom and active learning, demonstrated effectiveness. In addition, we used creative methods to teach clinical medicine during the ban on bedside teaching and modified community engagement activities to meet COVID-19 induced community needs.

CONCLUSIONS

The challenges and the lessons learned from teaching during the COVID-19 pandemic prompted us to adjust our teaching methods and curriculum using multiple online teaching methods and promoting self-learning. It also provided invaluable insights on our pedagogy and the teaching of medicine in the future with emphasis on students and faculty being part of the changes and adjustments in curriculum and teaching methods. However, personal interactions are essential to medical school education, as are laboratories, group simulations, and bedside teaching.

Neonatal SARS-CoV-2 Infections in Breastfeeding Mothers

OBJECTIVES

To assess infection rates predischarge and postdischarge in breast milk-fed newborns with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-positive mothers who were separated postdelivery from their mothers and discharged from the hospital. Also, we aim to evaluate breastfeeding rates predischarge and postdischarge.

METHODS

Nasopharyngeal swabs for SARS-CoV-2 were obtained from symptomatic and high-risk women in the delivery room. Mothers with positive SARS-CoV-2 test results were separated from the newborns. Newborns were screened within 48 hours of delivery, and anti-infectious guidelines were imparted to the mothers before discharge. Rescreening took place ≥14 days postdischarge. Data regarding SARS-CoV-2-positive household members and breastfeeding were obtained by follow-up phone calls.

RESULTS

A total of 73 newborns of SARS-CoV-2-positive mothers were born in Israel during the ∼3-month period under study. Overall, 55 participated in this study. All neonates tested negative for the virus postdelivery. A total 74.5% of the neonates were fed unpasteurized expressed breast milk during the postpartum separation until discharge. Eighty-nine percent of the neonates were discharged from the hospital after their mothers were instructed in anti-infection measures. In 40% of the households, there were additional SARS-CoV-2-positive residents. A total of 85% of the newborns were breastfed postdischarge. Results for all 60% of the newborns retested for SARS-CoV-2 postdischarge were negative.

CONCLUSIONS

No viral infection was identified in neonates born to and separated from their SARS-CoV-2-positive mothers at birth and subsequently fed unpasteurized breast milk. All infants breastfed at home remained SARS-CoV-2 negative. These findings may provide insights regarding the redundancy of postpartum mother-newborn separation in SARS-CoV-2-positive women and, assuming precautions are adhered to, support the safety of breast milk.

Using heated humidified high-flow nasal cannulas for premature infants may result in an underestimated amount of water reaching the airways

AIM

Condensation often occurs when providing humidified respiratory support. We examined conditions conducive to excess water formation in heated humified high-flow nasal cannula (HHHFNC).

METHODS

An HHHFNC device, at 35 or 37°C, was attached with a nasal cannula to a reservoir and tested in five ambient conditions and flows. For Group A, tubing and collection bottle remained at room temperature (23°C). Group B, tubing and reservoir remained inside an incubator (31°C). Group C, tubing and reservoir remained at 33°C. In Group D, the HHHFNC was set to 35°C, the reservoir remained at 33°C, and the nasal cannula and tubing remained at 23°C. Group E, same as D, with HHHFNC at 37°C.

RESULTS

The largest amounts of collected water were in groups A and E. Both had highest temperature differences. Median (range) was 4.9°C (4.1-6.9) and 4.0°C, collecting 38.4 (26.4-50.4) and 26.4 (19.2-50.4) ml/24 h, respectively. Smallest amounts of water were seen with lower temperature differences as in groups B, C, and D with 2.7 (1.9-4.7), 1.6 (1.2-2.1), and 2.0°C with 8.4 (0.0-33.6), 2.4 (0.0-14.4), and 9.6 (4.8-16.8) ml/24 h, respectively.

CONCLUSION

HHHFNC devices may produce clinically significant amounts of water reaching the upper airways. This may be prevented with appropriate device set-up.

Towards homogenization of liquid plug distribution in reconstructed 3D upper airways of the preterm infant

Liquid plug therapies are commonly instilled in premature babies suffering from infant respiratory distress syndrome (IRDS) by a procedure called surfactant replacement therapy (SRT) in which a surfactant-laden bolus is instilled endotracheally in the neonatal lungs, dramatically reducing mortality and morbidity in neonatal populations. Since data are frequently limited, the optimal method for surfactant delivery has yet to be established towards more standardized guidelines. Here, we explore the dynamics of liquid plug transport using an anatomically-relevant, true-scale in vitro 3D model of the upper airways of a premature infant. We quantify the initial plug's distribution as a function of two underlying parameters that can be clinically controlled; namely, the injection flow rate and the viscosity of the administered fluid. By extracting a homogeneity index (HI), our in vitro results underline how the combination of both high fluid viscosity and injection flow rates may be advantageous in improving homogeneous dispersion. Such outcomes are anticipated to help refine future SRT administration guidelines towards more uniform distribution using more anatomically-realistic 3D in vitro models at true scale of the preterm neonate.

[GETTING READY FOR THE FIRST MINUTE OF LIFE - THE DEVELOPMENT AND ORGANIZATION OF NEONATAL RESUSCITATION IN ISRAEL]

The recognition of the newborn as a separate patient with special unique needs and rights began relatively late compared to other medical disciplines. This process occurred concomitantly with the development of modern neonatology in the country and the establishment of special care nurseries. The process included organization of skilled teams, standardization of treatment methods, introduction of standardized language and practices, and teamwork optimization. The importance of providing support to a newborn in distress after birth - in the first minute, and as needed for the first hour of his life, coined as "The Golden Hour", is highlighted in the training sessions in the program. These principles are conveyed today in multiple simulation-based training courses of multidisciplinary teams taking place in most Israeli hospitals, based on the recommendations of the leading organizations in the field and following the consensus statements outlined by the International Liaison Committee for Resuscitation (ILCOR). This article describes the processes that enabled present achievements, and the goals for further future improvements in the outcomes of newborn resuscitation in Israel.

Ventilation-induced jet suggests biotrauma in reconstructed airways of the intubated neonate

We investigate respiratory flow phenomena in a reconstructed upper airway model of an intubated neonate undergoing invasive mechanical ventilation, spanning conventional to high-frequency ventilation (HFV) modes. Using high-speed tomographic particle image velocimetry, we resolve transient, three-dimensional flow fields and observe a persistent jet flow exiting the endotracheal tube whose strength is directly modulated according to the ventilation protocol. We identify this synthetic jet as the dominating signature of convective flow under intubated ventilation. Concurrently, our in silico wall shear stress analysis reveals a hitherto overlooked source of ventilator-induced lung injury as a result of jet impingement on the tracheal carina, suggesting damage to the bronchial epithelium; this type of injury is known as biotrauma. We find HFV advantageous in mitigating the intensity of such impingement, which may contribute to its role as a lung protective method. Our findings may encourage the adoption of less invasive ventilation procedures currently used in neonatal intensive care units.

While waiting for a vaccine: opportunities for optimization of neonatal group B streptococcal (GBS) disease prevention in Israel

OBJECTIVE

To quantify effects of different strategies for decreasing neonatal early onset GBS sepsis (EOGBS) in Israel.

STUDY DESIGN

A risk allocation model for EOGBS among infants ≥ 35w was adapted to Israeli data. Effects of strategies for antepartum (APS) and intrapartum (IPS) screening, and intrapartum (IAP) and/or postpartum antibiotic prophylaxis (PAP) were calculated.

RESULTS

Estimated EOGBS attack rates (AR) with APS in 90%, IAP in 90%, may reduce AR to 0.18/1000. A rapid intrapartum test would further decrease AR to 0.16/1000, while reducing IAP from 21.3 to 12.5% of women. For babies with risk factors and GBS+ who do not receive IAP, further risk reduction could be achieved by PAP.

CONCLUSION

IAP remains the main intervention to decrease EOGBS. IAP and PAP together may reduce EOGBS present incidence by 40%. Combining rapid intrapartum screening with selective IAP and selective PAP for remaining gaps, would be the most efficient strategy.

Red blood cell (RBC) suspensions in confined microflows: Pressure-flow relationship

Microfluidic-based assays have become increasingly popular to explore microcirculation in vitro. In these experiments, blood is resuspended to a desired haematocrit level in a buffer solution, where frequent choices for preparing RBC suspensions comprise notably Dextran and physiological buffer. Yet, the rational for selecting one buffer versus another is often ill-defined and lacks detailed quantification, including ensuing changes in RBC flow characteristics. Here, we revisit RBC suspensions in microflows and attempt to quantify systematically some of the differences emanating between buffers. We measure bulk flow rate (Q) of RBC suspensions, using PBS- and Dextran-40, as a function of the applied pressure drop (ΔP) for two hematocrits (∼0% and 23%). Two distinct microfluidic designs of varying dimensions are employed: a straight channel larger than and a network array similar to the size of individual RBCs. Using the resulting pressure-flow curves, we extract the equivalent hydrodynamic resistances and estimate the relative viscosities. These efforts are a first step in rigorously quantifying the influence of the 'background' buffer on RBC flows within microfluidic devices and thereby underline the importance of purposefully selecting buffer suspensions for microfluidic in vitro assays.

Red blood cell dynamics in biomimetic microfluidic networks of pulmonary alveolar capillaries

The pulmonary capillary networks (PCNs) embody organ-specific microvasculatures, where blood vessels form dense meshes that maximize the surface area available for gas exchange in the lungs. With characteristic capillary lengths and diameters similar to the size of red blood cells (RBCs), seminal descriptions coined the term "sheet flow" nearly half a century ago to differentiate PCNs from the usual notion of Poiseuille flow in long straight tubes. Here, we revisit in true-scale experiments the original "sheet flow" model and devise for the first time biomimetic microfluidic platforms of organ-specific PCN structures perfused with RBC suspensions at near-physiological hematocrit levels. By implementing RBC tracking velocimetry, our measurements reveal a wide range of heterogonous RBC pathways that coexist synchronously within the PCN; a phenomenon that persists across the broad range of pressure drops and capillary segment sizes investigated. Interestingly, in spite of the intrinsic complexity of the PCN structure and the heterogeneity in RBC dynamics observed at the microscale, the macroscale bulk flow rate versus pressure drop relationship retains its linearity, where the hydrodynamic resistance of the PCN is to a first order captured by the characteristic capillary segment size. To the best of our knowledge, our in vitro efforts constitute a first, yet significant, step in exploring systematically the transport dynamics of blood in morphologically inspired capillary networks.

Does Haptoglobin Phenotype Influence Postnatal Morbidity in Preterm Neonates?

BACKGROUND

Haptoglobin (Hp) is an acute phase protein with antioxidant, bacteriostatic, and anti-inflammatory activities. Hp proteins associated with the three major phenotypes differ in their proinflammatory and anti-inflammatory action. Inflammation and oxidative stress are both involved in most pathophysiological processes in premature infants. The objective of this study was to determine whether Hp phenotype influences clinical manifestations and sepsis incidence in the premature infants.

OBJECTIVE

Infants born before 35 weeks gestational age were prospectively evaluated for Hp phenotype and clinical events, including sepsis, necrotizing enterocolitis, bronchopulmonary dysplasia, intraventricular hemorrhage, and retinopathy of prematurity. The participants were observed until discharge.

METHODS

A total of 122 preterm infants were enrolled in the study. Clinical events were not affected by the Hp phenotype. The expression of Hp protein was extremely low in the study population. More septic episodes were found in infants with a birth weight greater than 1,500 g, although, the difference was not statistically significant.

RESULTS

Extremely low expression of Hp may explain the lack of a correlation between Hp phenotype and sepsis in preterm infants. Further research involving a larger neonatal population is required to better understand the role of the Hp phenotype in morbidity of premature infants.

Prophylactic treatment of asthma by an ozone scavenger in a mouse model

Our hypothesis that inflammation in asthma involves production of ozone by white blood cells and that ozone could be an inflammatory mediator suggests that scavengers of reactive oxygen species (ROS), for example, electron-rich olefins, could serve for prophylactic treatment of asthma. Olefins could provide chemical protection against either exogenous or endogenous ozone and other ROS. BALB/c mice pretreated by inhalation of d-limonene before an ovalbumin challenge exhibited significant attenuation of the allergic asthma symptoms. Diminution of the inflammatory process was evident by reduced levels of aldehydes, reduced counts of neutrophils in the BAL fluid and by histological tests. A surprising systemic effect was observed by decreased levels of aldehydes in the spleen, suggesting that the examination of tissues and organs that are remote from the inflammation foci could provide valuable information on the distribution of the oxidative stress and may serve as guide for targeted treatment.

Zn/Ga-DFO iron-chelating complex attenuates the inflammatory process in a mouse model of asthma

Background

Redox-active iron, a catalyst in the production of hydroxyl radicals via the Fenton reaction, is one of the key participants in ROS-induced tissue injury and general inflammation. According to our recent findings, an excess of tissue iron is involved in several airway-related pathologies such as nasal polyposis and asthma.

Objective

To examine the anti-inflammatory properties of a newly developed specific iron–chelating complex, Zn/Ga−DFO, in a mouse model of asthma.

Materials and methods

Asthma was induced in BALBc mice by ovalbumin, using aluminum hydroxide as an adjuvant. Mice were divided into four groups: (i) control, (ii) asthmatic and sham-treated, (iii) asthmatic treated with Zn/Ga−DFO [intra-peritoneally (i/p) and intra-nasally (i/n)], and (iv) asthmatic treated with Zn/Ga−DFO, i/n only. Lung histology and cytology were examined. Biochemical analysis of pulmonary levels of ferritin and iron-saturated ferritin was conducted.

Results

The amount of neutrophils and eosinophils in bronchoalveolar lavage fluid, goblet cell hyperplasia, mucus secretion, and peri-bronchial edema, showed markedly better values in both asthmatic-treated groups compared to the asthmatic non-treated group. The non-treated asthmatic group showed elevated ferritin levels, while in the two treated groups it returned to baseline levels. Interestingly, i/n-treatment demonstrated a more profound effect alone than in a combination with i/p injections.

Conclusion

In this mouse model of allergic asthma, Zn/Ga−DFO attenuated allergic airway inflammation. The beneficial effects of treatment were in accord with iron overload abatement in asthmatic lungs by Zn/Ga−DFO. The findings in both cellular and tissue levels supported the existence of a significant anti-inflammatory effect of Zn/Ga−DFO.

Asthma pathophysiology was shown to be associated with iron overload.

A therapeutic effect of the novel iron–chelating complexes was demonstrated.

Histological and cytological markers of inflammation were studied.

The complexes could be administered intranasally or by intraperitonneal injections.

Highly sensitive monitoring of chest wall dynamics and acoustics provides diverse valuable information for evaluating ventilation and diagnosing pneumothorax

Current practice of monitoring lung ventilation in neonatal intensive care units, utilizing endotracheal tube pressure and flow, end-tidal CO2, arterial O2 saturation from pulse oximetry, and hemodynamic indexes, fails to account for asymmetric pathologies and to allow for early detection of deteriorating ventilation. This study investigated the utility of bilateral measurements of chest wall dynamics and sounds, in providing early detection of changes in the mechanics and distribution of lung ventilation. Nine healthy New Zealand rabbits were ventilated at a constant pressure, while miniature accelerometers were attached to each side of the chest. Slowly progressing pneumothorax was induced by injecting 1 ml/min air into the pleural space on either side of the chest. The end of the experiment ( tPTX) was defined when arterial O2 saturation from pulse oximetry dropped <90% or when vigorous spontaneous breathing began, since it represents the time of clinical detection using common methods. Consistent and significant changes were observed in 15 of the chest dynamics parameters. The most meaningful temporal changes were noted for features extracted from subsonic dynamics (<10 Hz), e.g., tidal amplitude, energy, and autoregressive poles. Features from the high-frequency band (10–200 Hz), e.g., energy and entropy, exhibited smaller but significant changes. At 70% tPTX, identification of asymmetric ventilation was attained for all animals. Side identification of the pneumothorax was achieved at 50% tPTX, within a 95% confidence interval. Diagnosis was, on average, 34.1 ± 18.8 min before tPTX. In conclusion, bilateral monitoring of the chest dynamics and acoustics provide novel information that is sensitive to asymmetric changes in ventilation, enabling early detection and localization of pneumothorax.

[Why perform routine brain sonography in late preterm infants?]

We present a case of a late preterm baby with respiratory distress syndrome (RDS), prolonged jaundice and congenital hypothyroidism. The infant developed late lenticulostriate vasculopathy (LSV). LSV was previously described in association with various neurodevelopmental abnormalities and in this case would have been missed by the current US brain screening recommendations for newborns.

Design of aerosol face masks for children using computerized 3D face analysis

BACKGROUND

Aerosol masks were originally developed for adults and downsized for children. Overall fit to minimize dead space and a tight seal are problematic, because children's faces undergo rapid and marked topographic and internal anthropometric changes in their first few months/years of life. Facial three-dimensional (3D) anthropometric data were used to design an optimized pediatric mask.

METHODS

Children's faces (n=271, aged 1 month to 4 years) were scanned with 3D technology. Data for the distance from the bridge of the nose to the tip of the chin (H) and the width of the mouth opening (W) were used to categorize the scans into "small," "medium," and "large" "clusters."

RESULTS

"Average" masks were developed from each cluster to provide an optimal seal with minimal dead space. The resulting computerized contour, W and H, were used to develop the SootherMask® that enables children, "suckling" on their own pacifier, to keep the mask on their face, mainly by means of subatmospheric pressure. The relatively wide and flexible rim of the mask accommodates variations in facial size within and between clusters.

CONCLUSIONS

Unique pediatric face masks were developed based on anthropometric data obtained through computerized 3D face analysis. These masks follow facial contours and gently seal to the child's face, and thus may minimize aerosol leakage and dead space.

[Hypothermia as a treatment for hypoxic ischemic encephalopathy after neonatal asphyxia--update]

Hypoxic-ischemic encephalopathy (HIE) due to neonatal asphyxia is an important cause of irreversible bad neurodevelopmental outcomes in children. Understanding the mechanisms causing the central nervous system cell death enabled the development of new treatment strategies that may decrease the severity of neurological damage. This survey includes data on epidemiology, pathogenesis, clinical features and diagnostic criteria of HIE. We discuss the neuro-protective mechanisms of therapeutic hypothermia and provide data on clinical studies conducted to investigate the impact and safety of this treatment in newborn infants affected by HIE. In addition, other therapeutic options of neuro-protective agents are mentioned.

Nonimmune hydrops fetalis caused by G6PD deficiency hemolytic crisis and congenital dyserythropoietic anemia

We present a case of a female neonate who had a nonimmune hydrops fetalis and severe hemolytic anemia due to a rare combination of glucose-6-phosphate dehydrogenase (G6PD) deficiency and congenital dyserythropoietic anemia. We conclude that in severe cases with persistent anemia one should search after delivery for a second reason other than G6PD deficiency alone.

Transient decrease in PaCO(2) and asymmetric chest wall dynamics in early progressing pneumothorax

PURPOSE

Diagnosis of pneumothorax (PTX) in newborn infants has been reported as late. To explore diagnostic indices for early detection of progressing PTX, and offer explanations for delayed diagnoses.

METHODS

Progressing PTX was created in rabbits (2.3 ± 0.5 kg, n = 7) by injecting 1 ml/min of air into the pleural space. Hemodynamic parameters, tidal volume, EtCO(2), SpO(2), blood gas analyses and chest wall tidal displacements (TDi) on both sides of the chest were recorded.

RESULTS

(Mean ± SD): A decrease in SpO(2) below 90 % was detected only after 46.6 ± 11.3 min in six experiments. In contrary to the expected gradual increase of CO(2), there was a prolonged transient decrease of 14.2 ± 4.5 % in EtCO(2) (p < 0.01), and a similar decrease in PaCO(2) (p < 0.025). EtCO(2) returned back to baseline only after 55.2 ± 24.7 min, and continued to rise thereafter. The decrease in CO(2) was a mirror image of the 14.6 ± 5.3 % increase in tidal volume. The analysis of endotracheal flow and pressure dynamics revealed a paradoxical transient increase in the apparent compliance. Significant decrease in mean arterial blood pressure was observed after 46.2 ± 40.1 min. TDi provided the most sensitive and earliest sign of PTX, decreasing on the PTX side after 16.1 ± 7.2 min. The TDi progressively decreased faster and lower on the PTX side, thus enabling detection of asymmetric ventilation.

CONCLUSIONS

The counterintuitive transient prolonged decrease in CO(2) without changes in SpO(2) may explain the delay in diagnosis of PTX encountered in the clinical environment. An earlier indication of asymmetrically decreased ventilation on the affected side was achieved by monitoring the TDi.

A new method for continuous monitoring of chest wall movement to characterize hypoxemic episodes during HFOV

INTRODUCTION

Monitoring ventilated infants is difficult during high-frequency oscillatory ventilation (HFOV). This study tested the possible causes of hypoxemic episodes using a new method for monitoring chest wall movement during HFOV in newborn infants.

METHODS

Three miniature motion sensors were attached to both sides of the chest and to the epigastrium to measure the local tidal displacement (TDi) at each site. A >20% change in TDi was defined as deviation from baseline.

RESULTS

Eight premature infants (postmenstrual age 30.6 ± 2.6 weeks) were monitored during 10 sessions (32.6 h) that included 21 hypoxemic events. Three types of such events were recognized: decrease in TDi that preceded hypoxemia (n = 11), simultaneous decrease in TDi and SpO2 (n = 6), and decrease in SpO(2) without changes in TDi (n = 4). In the first group, decreases in TDi were detected 22.4 ± 18.7 min before hypoxemia, and were due to airway obstruction by secretions or decline in lung compliance. The second group resulted from apnea or severe abdominal contractions. In the third group, hypoxia appeared following a decrease in FiO2.

CONCLUSIONS

Monitoring TDi may enable early recognition of deteriorating ventilation during HFOV that eventually leads to hypoxemia. In about half of cases, hypoxemia is not due to slowly deteriorating ventilation.

Benefits of high frequency oscillatory ventilation for premature infants

BACKGROUND

High frequency oscillatoryventilation based on optimal lung volume strategy is one of the accepted modes of ventilatory support for respiratory distress syndrome in very low birth weight infants. In 1999 itwas introduced in our unit as the primary ventilation modality for RDS.

OBJECTIVES

To evaluate if the shift to HFOV influenced the outcome of ventilated VLBW infants in the neonatal intensive care unit of Carmel Medical Center.

METHODS

Data were obtained from the medical charts of VLBW infants born at Carmel Medical Center, and late mortality data from the Israel Ministry of Internal Affairs records. A retrospective analysis and a comparison with a historical control group ventilated by the conventional method were performed.

RESULTS

A total of 232 VLBW infants with RDS were mechanically ventilated during the period 1995 to 2003: 120 were ventilated using HFOV during 1999-2003 and 102 infants using CV during 1995-1999. The mean gestational age of survivors was 27.4 +/- 2 weeks in the HFOV group and 28.4 +/- 2 in the conventional ventilation group (P = 0.03). The sub-sample of infants with birth weight < 1000 g ventilated with HFOV showed higher survival rates than the infants in the conventional ventilation group, 53 vs. 25 (64.6% vs. 44.6%) respectively (P < 0.05). A trend for lower incidence of pulmonary interstitial emphysema was observed in the HFOV group.

CONCLUSIONS

The introduction of HFOV based on optimal lung volume strategy proved to be an efficient and safe method of ventilation support for VLBW infants in our unit.

Subpleural microvascular flow velocities and shear rates in normal and septic mechanically ventilated rats

Changes in pulmonary microhemodynamics are important variables in a large variety of pathological processes. We used in vivo fluorescent videomicroscopy of the subpleural microvasculature in mechanically ventilated rats to directly monitor microvascular flow velocity (FV) and shear rate in pulmonary arterioles, capillaries, and venules in healthy rats and in septic rats 20 h after cecal ligation and puncture (CLP). Observations were made through a small thoracotomy after injection of fluorescent microspheres (D = 1 microm) into the systemic circulation. The FVs were calculated off-line by frame-by-frame measurements of the distance covered by individual microspheres per unit of time. In healthy rats, inspiratory FV were 1322 +/- 142 microm/s in subpleural arterioles and 599 +/- 25 microm/s in capillaries. The highest FV was found in venules (1552 +/- 132 microm/s). The calculated shear rates were 547 +/- 62/s in arterioles and 619 +/- 19/s in capillaries. The highest shear rates were detected in venules (677 +/- 59/s). No significant changes in FV and shear rates were observed throughout the 1-h observation period in any of the microvascular compartments. Pulmonary microvascular FV and shear rates found in sham-operated rats in the CLP experiments were not significantly different from values of healthy rats. The CLP caused a significant increase in leukocyte sequestration in the lungs and a mean of 27% to 34% decrease in FV in all sections of the pulmonary microvasculature (P < 0.001 in capillaries and P < 0.05 in venules). Also, CLP caused a 23% decrease in capillary shear rate that reached only borderline statistical significance (P < 0.06) and a significant 35% decrease in mean shear rate in venules (P < 0.05). Fluorescent videomicroscopy is offered as a stable and reproducible method for in vivo determinations of pulmonary microhemodynamics in clinically relevant models of sepsis.

The anuric preterm newborn infant with a normal renal ultrasound: a diagnostic and ethical challenge

Diagnosis and treatment of an anuric premature infant with severe respiratory compromise and a normal renal ultrasound (US), is a difficult task that requires a multidisciplinary approach. A 29-week gestation premature male infant, born after 5 weeks of worsening oligohydramnios, was ventilated for respiratory distress and remained anuric. Intensive clinical investigations and pediatric nephrology consultation that predicted very poor prognosis were followed by progressive renal failure, electrolyte imbalance, respiratory failure, ventricular arrhythmia, and finally cardiac arrest and death on day 5. In view of the predicted poor outcome, and after discussion with the parents, a decision was made not to start peritoneal dialysis (PD), and to offer only palliative therapy, with comfort care alone. Pre and postnatal diagnosis lead, in this case, to an ethical challenge that focuses on the question of futility.

A model for second-trimester Down syndrome sonographic screening based on facial landmarks and digit length measurement

OBJECTIVE

To determine whether Down syndrome can be detected by combining measurements of fetal nasal bone (NB) length, prenasal thickness (PT) and digits 2 and 3 of the hand.

METHODS

Two hundred and fifty-four normal and 25 Down-syndrome fetuses were scanned between 15 and 33 weeks' gestation. Physicians performing the scans were not blinded to the fetal karyotype. Both PT and NB were measured in a mid-sagittal plane. For PT measurement calipers were placed between the frontonasal angle and the outer skin edge. Digits 2 and 3 of one hand were also measured. The results (except for PT/NB ratio) were expressed in multiples of the normal gestation-specific median (MoM). A logistic regression model was used to estimate the odds of the fetus having Down syndrome given different combinations of NB, PT, PT/NB ratio, and digits 2 and 3 measurements. The odds were used to calculate the risk of Down syndrome for each pregnant woman from her age and measurements.

RESULTS

The median PT MoM for unaffected fetuses and Down-syndrome fetuses was 1.12 vs. 1.35 (P < 0.0001). The median NB MoM for unaffected and Down-syndrome fetuses was 1.03 vs. 0.81 (P < 0.001) and the PT/NB ratio MoM for unaffected and Down-syndrome fetuses was 0.63 vs. 0.96 (P < 0.001). The respective median MoM values for digits 2 and 3 of the Down-syndrome fetuses were significantly smaller (0.81 vs. 0.93 and 0.89 vs. 0.95, respectively, P = 0.003). Only the PT/NB ratio and digit 2 were finally included in the logistic regression equation. Using a 1 in 200 risk cut-off, the observed sensitivity and false-positive rate were 76% and 6.7%, respectively.

CONCLUSION

Combining the PT/NB ratio and digit 2 measurements yielded a promising screening detection rate. Confirmation of our findings in a prospective study is needed before the method can be used clinically.

[Trends of electronic publishing in medicine and life sciences]

Scientific publication in the electronic media is gaining popularity in academic libraries, research institutions and commercial organizations. The electronic journal may shorten the processes of writing and publication, decrease publication and distribution costs, and enable access from any location in the world. Electronic publications have unique advantages: it is possible to search them, to create hyperlinks to references and footnotes, as well as to information on the web and to include graphics and photographs at a very low cost. Audio, video and tri-dimensional images may also be included. Electronic publishing may also speed up review and publication processes and enable the writer to receive immediate feedback through the web. However, in spite of the advantages, there are certain points that must be considered: accessibility to previously published material is not guaranteed as databases are not always stable and coverage may change without notice. In addition, the price that commercial publishers charge for their services may be very high or be subject to the purchase of a packaged deal that may include unwanted databases. Many issues of copyright and the use of published material are not yet finalized. In this review we discuss the advantages and disadvantages of the electronic scientific publication, the feasibility of keeping appropriate quality and peer-review process, the stability and accessibility of databases managed by the publishers and the acceptance of the electronic format by scientists and clinicians.

An automated method for analysis of flow characteristics of circulating particles from in vivo video microscopy

The behavior of white and red blood cells, platelets, and circulating injected particles is one of the most studied areas of physiology. Most methods used to analyze the circulatory patterns of cells are time consuming. We describe a system named CellTrack, designed for fully automated tracking of circulating cells and micro-particles and retrieval of their behavioral characteristics. The task of automated blood cell tracking in vessels from in vivo video is particularly challenging because of the blood cells' nonrigid shapes, the instability inherent in in vivo videos, the abundance of moving objects and their frequent superposition. To tackle this, the CellTrack system operates on two levels: first, a global processing module extracts vessel borders and center lines based on color and temporal patterns. This enables the computation of the approximate direction of the blood flow in each vessel. Second, a local processing module extracts the locations and velocities of circulating cells. This is performed by artificial neural network classifiers that are designed to detect specific types of blood cells and micro-particles. The motion correspondence problem is then resolved by a novel algorithm that incorporates both the local and the global information. The system has been tested on a series of in vivo color video recordings of rat mesentery. Our results show that the synergy between the global and local information enables CellTrack to overcome many of the difficulties inherent in tracking methods that rely solely on local information. A comparison was made between manual measurements and the automatically extracted measurements of leukocytes and fluorescent microspheres circulatory velocities. This comparison revealed an accuracy of 97%. CellTrack also enabled a much larger volume of sampling in a fraction of time compared to the manual measurements. All these results suggest that our method can in fact constitute a reliable replacement for manual extraction of blood flow characteristics from in vivo videos.

Effects of inhaled nitric oxide on lung injury after intestinal ischemia-reperfusion in rats

Splanchnic ischemia/reperfusion (I/R) induces a systemic inflammatory response with acute lung injury. Impaired production of endothelial nitric oxide (NO) plays a key role in this process. We evaluated the effects of early treatment with inhaled NO (iNO) on lung microcirculatory inflammatory changes during splanchnic I/R. I/R was induced in rats by occlusion of the superior mesenteric artery (SMA; 40 min) and reperfusion (90 min). Four groups were studied: Control, anesthesia only; Sham, all surgical procedures without I/R, ventilated with air; Air, SMA I/R, ventilation with air; and NO, SMA I/R, ventilation with NO (20 ppm) starting 10 min before reperfusion. Intravital video microscopy was used to monitor pulmonary macromolecular flux and capillary flow velocity (CFV). Leukocyte infiltration was determined by morphometry. SMA I/R decreased mean arterial blood pressure, capillary CFV (P < 0.01), and shear rate (P < 0.01), and increased pulmonary macromolecular leak by 138% +/- 8% (P < 0.001). iNO markedly attenuated the increase in macromolecular leak (P < 0.01), blunted the decrease in capillary CFV (P < 0.05) and shear rate (P < 0.05), and prevented the increase in leukocyte infiltration of the lungs after SMA I/R (P < 0.05). The direct, real-time, in vivo data suggest that early institution of low-dose iNO therapy effectively ameliorates the acute remote pulmonary inflammatory response after splanchnic I/R.

Effects of hyperoxia on local and remote microcirculatory inflammatory response after splanchnic ischemia and reperfusion

Splanchnic ischemia-reperfusion (I/R) causes tissue hypoxia that triggers local and systemic microcirculatory inflammatory responses. We evaluated the effects of hyperoxia in I/R induced by 40-min superior mesenteric artery (SMA) occlusion and 120-min reperfusion in four groups of rats: 1) control (anesthesia only), 2) sham operated (all surgical procedures without vascular occlusion; air ventilation), 3) SMA I/R and air, 4) SMA I/R and 100% oxygen ventilation started 10 min before reperfusion. Leukocyte rolling and adhesion in mesenteric microvessels, pulmonary microvascular blood flow velocity (BFV), and macromolecular (FITC-albumin) flux into lungs were monitored by intravital videomicroscopy. We also determined pulmonary leukocyte infiltration. SMA I/R caused marked decreases in mean arterial blood pressure (MABP) and blood flow to the splanchnic and hindquarters vascular beds and pulmonary BFV and shear rates, followed by extensive increase in leukocyte rolling and adhesion and plugging of >50% of the mesenteric microvasculature. SMA I/R also caused marked increase in pulmonary sequestration of leukocytes and macromolecular leak with concomitant decrease in circulating leukocytes. Inhalation of 100% oxygen maintained MABP at significantly higher values (P < 0.001) but did not change regional blood flows. Oxygen therapy attenuated the increase in mesenteric leukocyte rolling and adherence (P < 0.0001) and maintained microvascular patency at values not significantly different from sham-operated animals. Hyperoxia also attenuated the decrease in pulmonary capillary BFV and shear rates, reduced leukocyte infiltration in the lungs (P < 0.001), and prevented the increase in pulmonary macromolecular leak (P < 0.001), maintaining it at values not different from sham-operated animals. The data suggest that beneficial effects of normobaric hyperoxia in splanchnic I/R are mediated by attenuation of both local and remote inflammatory microvascular responses.

Effect of maternal tocolysis on the incidence of severe periventricular/intraventricular haemorrhage in very low birthweight infants

AIM

To examine the relation between grade III-IV periventricular/intraventricular haemorrhage (PVH/IVH) and antenatal exposure to tocolytic treatment in very low birthweight (VLBW) premature infants.

STUDY DESIGN

The study population consisted of 2794 infants from the Israel National VLBW Infant Database, of gestational age 24-32 weeks, who had a cranial ultrasound examination during the first 28 days of life. Infants of mothers with pregnancy induced hypertension or those exposed to more than one tocolytic drug were excluded. Of the 2794 infants, 2013 (72%) had not been exposed to tocolysis and 781 (28%) had been exposed to a single tocolytic agent. To evaluate the effect of tocolysis and confounding variables on grade III-IV PVH/IVH, the chi(2) test, univariate analysis, and a logistic regression model were used.

RESULTS

Of the 781 infants (28%) exposed to tocolysis, 341 (12.2%) were exposed to magnesium sulphate, 263 (9.4%) to ritodrine, and 177 (6.3%) to indomethacin. The overall incidence of grade III-IV PVH/IVH was 13.4%. In the multivariate logistic regression analysis, the following factors were related significantly and independently to grade III-IV PVH/IVH: no prenatal steroid treatment, low gestational age, one minute Apgar score 0-3, respiratory distress syndrome, patent ductus arteriosus, mechanical ventilation, and pneumothorax. Infants exposed to ritodrine tocolysis (but not to the other tocolytic drugs) were at significantly lower risk of grade III-IV PVH/IVH after adjustment for other variables (odds ratio = 0.3; 95% confidence interval 0.2 to 0.6).

CONCLUSION

This study suggests that antenatal exposure of VLBW infants to ritodrine tocolysis, in contrast with tocolysis induced by magnesium sulphate or indomethacin, was associated with a lower incidence of grade III-IV PVH/IVH.

The effect of glucocorticoids on the expression of L-selectin on polymorphonuclear leukocyte

When active bone marrow release is induced by inflammatory stimuli, it is associated with an increase in L-selectin expression on circulating polymorphonuclear leukocyte (PMN). This contrasts sharply with glucocorticoid-induced granulocytosis that is associated with decreased L-selectin expression on PMN. The present study was designed to determine if the reduced L-selectin expression observed after glucocorticoid treatment is the result of suppression of L-selectin synthesis in the bone marrow. New Zealand white rabbits treated with dexamethasone (2.0 mg/kg, a single dose intravenously) were shown to have decreased L-selectin expression on circulating PMN 12 to 24 hours after treatment (P <.01) with a return to baseline levels by 48 hours. When dexamethasone was administered 48 hours after the bone marrow PMN were pulse labeled with the thymidine analogue, 5'-bromo-2'-deoxyuridine (BrdU), L-selectin expression on BrdU-labeled PMN released from the bone marrow was decreased (P <.01). Dexamethasone decreased L-selectin expression on segmented PMN in the bone marrow (P <.05) but not on PMN already in the circulation. We conclude that glucocorticoids decrease L-selectin expression on circulating PMN by downregulating L-selectin expression in the maturation pool of bone marrow and speculate that this is an important glucocorticoid effect that influences the recruitment of PMN into inflammatory sites.

Effect of vitamin K1 on glucose-6-phosphate dehydrogenase deficient neonatal erythrocytes in vitro

AIM

To determine whether vitamin K1, which is routinely administered to neonates, could act as an exogenous oxidising agent and be partly responsible for haemolysis in glucose-6-phosphat-dehydrogenase (G-6-PD).

METHODS

G-6-PD deficient (n = 7) and control (n = 10) umbilical cord blood red blood cells were incubated in vitro with a vitamin K1 preparation (Konakion). Two concentrations of Vitamin K1 were used, both higher than that of expected serum concentrations, following routine injection of 1 mg vitamin K1. Concentrations of reduced glutathione (GSH) and methaemoglobin, indicators of oxidative red blood cell damage, were determined before and after incubation, and the mean percentage change from baseline calculated.

RESULTS

Values (mean (SD)) for GSH, at baseline, and after incubation with vitamin K1 at concentrations of 44 and 444 microM, respectively, and percentage change from baseline (mean (SD)) were 1.97 + 0.31 mumol/g haemoglobin, 1.89 +/- 0.44 mumol/g (-4.3 +/- 13.1%), and 1.69 +/- 0.41 mumol/g (-14.5 +/- 9.3%) for the G-6-PD deficient red blood cells, and 2.27 +/- 0.31 mumol/g haemoglobin, 2.09 +/- 0.56 mumol/g (-7.2 +/- 23.2%), and 2.12 +/- 0.38 mumol/g (-6.0 + 14.1%) for the control cells. For methaemoglobin (percentage of total haemoglobin), the corresponding values were 2.01 +/- 0.53%, 1.93 +/- 0.37% (-0.6 +/- 17.4%) and 2.06 +/- 0.43% (5.7 +/- 14.2%) for the G-6-PD deficient red blood cells, and 1.56 +/- 0.74%, 1.70 +/- 0.78% (12.7 +/- 21.9%), and 1.78 +/- 0.71% (20.6 +/- 26.8%) for the control red blood cells. None of the corresponding percentage changes from baseline was significantly different when G-6-PD deficient and control red blood cells were compared.

CONCLUSIONS

These findings suggest that G-6-PD deficient red blood cells are not at increased risk of oxidative damage from vitamin K1.

Hyperbaric oxygen therapy in the pediatric patient: the experience of the Israel Naval Medical Institute

The pediatric patient is to be found in hyperbaric facilities throughout the world, receiving hyperbaric oxygen (HBO) therapy for both life-threatening and chronic diseases.

OBJECTIVE

To review the experience accumulated at the Israel Naval Medical Institute in the treatment of pediatric patients.

DESIGN

A retrospective analysis and review of all records of patients younger than age 18 years.

RESULTS

Between 1980 and 1997, 139 pediatric patients age 2 months to 18 years (mean, 7.7 years) received HBO treatment at the Israel Naval Medical Institute. Of the children, 111 (79%) suffered from acute carbon monoxide (CO) poisoning; 13 (9.2%) were treated after crush injury, traumatic ischemia, or compartment syndrome; 4 (2.8%) had clostridial myonecrosis; 1 (0.7%) had necrotizing fasciitis; 5 (3.6%) had refractory osteomyelitis; 2 (1.4%) had suffered massive air embolism; 2 (1.4%) had purpura fulminans; and 1 (0.7%) suffered from decompression sickness. Outcome, judged by neurologic sequelae, mortality, and extent of soft tissue loss and limb amputation, was favorable in 129 patients (93%). Two patients (1.4%) died, 1 as a result of CO poisoning and the other, gas gangrene; 2 of the patients in the CO group (1.4%) remained with neurologic sequelae, and 6 patients in the acute traumatic ischemia group (4.3%) underwent limb amputation.

CONCLUSIONS

We had a favorable experience with 129 of a total 139 pediatric patients treated at our facility for the indications listed. A basic knowledge of HBO therapy is needed to refer the pediatric patient for treatment when indicated. The needs of the pediatric patient, especially the critically ill, require specific skills and equipment inside the hyperbaric chamber. Close collaboration between the pediatrician and the hyperbaric medicine physician is essential to ensure adequate care for infants and children.

L-selectin expression on polymorphonuclear leukocytes and monocytes in premature infants: reduced expression after dexamethasone treatment for bronchopulmonary dysplasia

We examined the effect of dexamethasone on the expression of the adhesion molecule L-selectin on circulating polymorphonuclear leukocytes (PMLs) and monocytes from premature infants with bronchopulmonary dysplasia (BPD). Nineteen infants who received dexamethasone (Dex group) and 28 who did not receive dexamethasone (no Dex group) were studied. L-selectin expression, measured as mean fluorescence intensity, was lower on circulating PMLs (5.7 +/- 0.6 vs 10.6 +/- 0.7, p < 0.001) and monocytes (7.9 +/- 0.9 vs 12.5 +/- 0.9, p < 0.02) isolated from those who had received dexamethasone. Because L-selectin is important for the recruitment of PMLs to inflammatory foci in the lungs, we speculate that one of the mechanisms by which dexamethasone reduces inflammation in BPD is by impairing the ability of leukocytes to migrate into the BPD lesions.

Bone marrow infusion in adults

OBJECTIVE

To asses the feasibility and success rate of vascular access through intraosseous infusions in adults, in elective and emergency situations using a novel, automatic device, the bone injection gun.

DESIGN

A prospective, nonrandomized trial.

MATERIALS AND METHODS

Two groups of patients were prospectively selected over an 11-month period. Group 1: Adult patients with recent closed long bone fractures, who underwent orthopedic surgery to upper and lower limbs and needed regional anesthesia. Group 2: Adult patients who required emergency or semiemergency vascular access, in whom intravenous central or peripheral cannulation could not be established within a reasonable period of time.

MAIN RESULTS

Fifty adult patients, aged 27 through 78 years, underwent the procedure, which was universally successful. In group 1, n = 31 patients; in group 2 (n = 19), 12 patients had multiple injuries, and seven underwent emergency resuscitation. In 76% of the cases, the needle was inserted into the area of the tibial tuberosity; in the reminder of the cases, the needle was inserted at the distal end of the radial bone and into the lateral or the medial malleolus. The success rate for an adequate insertion was 100% in this group of patients. No complications from the procedure were observed in this series.

CONCLUSIONS

This study emphasizes the importance and feasibility of the intraosseous route for infusion of fluids and medications in emergency situations in adults. The use of an impact, high speed automatic needle insertion device provides a higher success rate of vascular access via the intraosseal route in adult patients.