The effect of unilateral chest drainage for transpulmonary pressure during mechanical ventilation.

INTRODUCTION: Chest tube drainage is usually performed through an underwater seal at a level of 10-20 cmH2O. Based on the definition of transpulmonary pressure, continuous chest drainage creates continuous negative pressure, decreasing pleural surface pressure and increasing transpulmonary pressure. We investigated how unilateral chest drainage could affect the tidal volume or driving pressure during mandatory mechanical ventilation. METHODS: This study was an experimental study using a lung-thoracic model and anesthesia ventilator. Tidal volume was set to 300 mL with pressure-controlled ventilation or volume-controlled ventilation. Left tidal volume and right tidal volume were measured independently using respirometers with positive end-expiratory pressure (PEEP) levels of 0, 10, and 20 cmH2O. Simultaneously, left negative pressure of the chest drainage was changed to 0, 10, and 20 cmH2O. RESULTS: In all conditions, a tidal volume of 300 mL was achieved. In both pressure-controlled ventilation and volume-controlled ventilation, the left tidal volume increased with the application of chest drainage at 10 cmH2O when the PEEP level was 0 cmH2O, but left tidal volume decreased with the application of chest drainage at 20 cmH2O. Furthermore, when PEEP was 10 cmH2O, the left tidal volume decreased in proportion to the pressure of thoracic drainage. The right tidal volumes changed inversely with their counterpart left tidal volumes. CONCLUSION: Unilateral chest drainage caused unbalanced ventilation of the left and right lungs regardless of pressure-controlled ventilation or volume-controlled ventilation.

Use of intraoperative transesophageal echocardiography and epiaortic ultrasound to diagnose false lumen enlargement of chronic aortic dissection.

In communicating aortic dissection, if only the entry or reentry is closed, residual blood flow may cause enlargement of the false lumen. In this case, surgeons were unable to occlude the entry with a stent graft due to the strong flexion of the bilateral common iliac arteries, so they closed only the reentry in the hope that blood flow from the reentry would be high. Unfortunately, due to the high blood flow from the entry, the false lumen was enlarged. But the use of transesophageal echocardiography and epiaortic ultrasound contributed to its diagnosis.

Integrated Assessment of Discrepancy Between Tracheal Tube and Tube Exchanger as Advancement: A Manikin Simulation Study.

BACKGROUND: Advancing a tracheal tube over a tracheal tube exchanger into the trachea frequently causes difficulties because of the tube impingement on laryngeal structures. In the present study, we measured the resistance of tube advancement both objectively and subjectively with a variety of combinations of tube exchanger sizes and tracheal tubes using a manikin simulator. METHODS: Lubricated 7.5 mm ID standard and Parker Flex-Tip (PFT) tracheal tubes were railroaded over the tube exchangers (OD 1-6 mm) into the trachea through the oral route in a manikin. Consequently, 12 combinations of tracheal tube-exchanger tube assemblies were evaluated. Tube advancing resistance at the laryngeal inlet was subjectively evaluated. The objective tube advancing resistance (force) at the laryngeal inlet was evaluated using a digital force gauge. The execution of each tracheal tube-exchanger trial was conducted 10 times. RESULTS: With a 1-mm tube exchanger, all intubation attempts with both standard and PFT tubes failed. Esophageal intubation or severe impingement at the right arytenoid accompanied with a bent tracheal tube was observed. With a 2-mm tube exchanger, during intubation with a standard tracheal tube, rotation of the tube was sometimes required; however, all other intubations were done without problems. When PFT tubes were used, all intubation attempts were performed without problems. The rest of the trials were successfully performed regardless of the combinations of tube exchangers and tracheal tubes; however, one attempt of intubation with a combination of a 5 mm tube exchanger and a standard tracheal tube required withdrawal and rotation of the tube because of impingement at the epiglottis. In cases where there was no gap resistance, which means tube advancing resistance generated by a gap between an introducer and a tracheal tube, the pressing force was approximately less than 10 N. However, in the cases requiring some interventions to overcome the gap, the pressing force reached around 15 N. When intubation failed, for example when the tube bent, or esophageal intubation, the pressing force reached around 30 N. CONCLUSIONS: Impingement due to the gap between the tube exchanger and the tracheal tube is thought to occur in the PFT tube less frequently. Once an impingement occurs, we can feel approximately twice the amount of resistance as usual, which may be a chance to consider taking some interventions. When the impingement is not released, regardless of interventions, excessive force may result in esophageal intubation or tracheal injury.

A Case of Silent COVID-19 Pneumonia Found by an Optional Chest CT Scan During a Health Check.

We experienced a case of silent Coronavirus disease 2019 (COVID-19) pneumonia that was found by an optional chest computed tomography (CT) scan during a health check. A 62-year-old man with a present medical history of hypertension visited the health screening center at Tokai University Tokyo Hospital on August 7th, 2020. Prior to entry into the hospital, his body temperature was measured and his history was obtained (called 'COVID-19 triage'), but there were no remarkable findings. Subsequently, patchy ground glass opacities were observed with peripheral distribution in bilateral multiple lobes. Based on this finding COVID-19 pneumonia was highly suspected. Subsequently, a PCR test was positive for COVID-19. Even in health check settings, we should be aware of possible encounters with COVID-19 infections. The high risk of silent spread plays a significant role in the ongoing pandemic. Chest CT scans, which can efficiently identify silent COVID-19 pneumonia, should be performed earlier during health check examinations, at least before gastroendoscopy, which causes significant droplet dispersion. Health check examination providers should not cancel or postpone health checks; rather, it is necessary for them to provide health check examinees with a safe environment with minimal delay in access to recommended health care services.

Transient maintenance of tracheal patency upon the insertion of a flexible bronchoscope in a patient with an anterior mediastinal mass: a case report.

BACKGROUND: Patients with an anterior mediastinal mass are at risk of perioperative respiratory collapse. CASE PRESENTATION: A 74-year-old woman with a large anterior mediastinal mass that led to partial tracheal collapse (shortest diameter, 1.3 mm) was scheduled for tracheobronchial balloon dilation and stent placement under general anesthesia. Although veno-venous extracorporeal membrane oxygenation (V-V ECMO) had been established, maximum flow was limited to 1.6 L/min, and general anesthesia induction was followed by hypoxia probably due to inadequate ventilation. A flexible bronchoscope was inserted through the tracheal lumen that was being compressed by the anterior mass; this not only increased tracheal patency but also enabled positive pressure ventilation and resulted in recovery from hypoxia. Scheduled procedures were successfully performed without complications. CONCLUSION: We describe a case wherein tracheal patency was transiently maintained by inserting a flexible bronchoscope in a patient with an anterior mediastinal mass.

Effect of Soft X-ray Irradiation on Film Properties of a Hydrogenated Si-Containing DLC Film.

The effect of soft X-ray irradiation on hydrogenated silicon-containing diamond-like carbon (Si-DLC) films intended for outer space applications was investigated by using synchrotron radiation (SR). We found that the reduction in film thickness was about 60 nm after 1600 mA·h SR exposure, whereas there was little change in their elemental composition. The reduction in volume was attributable to photoetching caused by SR, unlike the desorption of hydrogen in the case of exposure of hydrogenated DLC (H-DLC) film to soft X-rays. The ratio of the sp2 hybridization carbon and sp3 hybridization carbon in the hydrogenated Si-DLC films, sp2/(sp2 + sp3) ratio, increased rapidly from ~0.2 to ~0.5 for SR doses of less than 20 mA·h. SR exposure significantly changed the local structure of carbon atoms near the surface of the hydrogenated Si-DLC film. The rate of volume reduction in the irradiated hydrogenated Si-DLC film was 80 times less than that of the H-DLC film. Doping DLC film with Si thus suppresses the volume reduction caused by exposure to soft X-rays.

Intra-aneurysmal embolization of cellulose porous beads to regenerate vessel wall: an experimental study.

PURPOSE: Although the treatment of intracranial cerebral aneurysms with detachable coils is now widely accepted, the problem of coil compaction and recanalization remains unsolved. If the vessel wall can be regenerated at the neck orifice of an aneurysm, thereby reducing the blood flow into the aneurysm, the recurrence rate of the aneurysm would decrease. Accordingly, we aimed to insert cellulose porous beads (CPBs) into rat models of external carotid artery (ECA) aneurysm and study their efficacy in promoting vessel wall regeneration. METHODS: Using a rat aneurysm model, we examined the tissue response to CPBs that were inserted into the ligated ECA sac of rats. The sacs were removed on days 14, 42, 84, and 180 after insertion and subjected to conventional and immunohistochemical examination. We evaluated the tissue response in the ECA sacs and observed the vessel wall regeneration progress. RESULTS: At the neck orifice of the aneurysm in which the CPB was inserted, a layer of regenerating α-smooth muscle actin-positive spindle cells was observed on day 14. The regenerative cell layer gradually thickened until day 42 and, thereafter, the thickness remained unchanged until day 180. A monolayer of factor VIII-positive cells also appeared at the neck orifice on day 14 and covered the entire orifice until day 180. The CPBs were stably localized in the sac without degradation or signs of inflammation. CONCLUSION: CPBs may be promising as embolic materials that can induce stable vessel wall regeneration at the neck orifice of an aneurysm without surrounding inflammatory reactions.

Technical Obstacles for Low-Volume Surgeons in Primary Anterior Cruciate Ligament Reconstruction.

A longer surgical time will lead to postoperative complications in orthopaedic surgery. According to previous reports, surgeon volume affects a surgical time in anterior cruciate ligament (ACL) reconstruction. However, little attention has been paid to difference of a surgical time between high- and low-volume surgeons in ACL reconstruction. The purpose of the present study was to investigate the surgical time for both high- and low-volume surgeons and to clarify technical obstacles as well as the important technique to reduce the surgical time in ACL reconstruction. A total of 103 knees in 103 patients with ACL tear were enrolled. All the procedures were performed by 13 different surgeons. The surgeons were divided into two surgeon groups (high- and low-volume groups) based on the number of annual cases. The operative technique was divided into the same five steps to perform comparisons of step-by-step surgical time between the surgeon groups of different volumes. The statistical comparison was done between high- and low-volume groups in terms of surgical time in each step. Total operation times were 87.8 ± 17.6 and 129.9 ± 42.9 minutes in high- and low-volume group, respectively. Low-volume surgeons took much time in tendon harvesting and bone tunnel creation using arthroscopy. Low-volume surgeons took more time for primary ACL reconstruction, especially in tendon harvesting, compared with high-volume surgeons. Tendon harvesting was extremely important, as well as bone tunnel creation, for low-volume surgeons to reduce surgical time in primary ACL reconstruction.

Late Onset of the Fabella Syndrome after Total Knee Arthroplasty.

Some differential diagnosis is thought due to knee pain after total knee arthroplasty (TKA) and fabella syndrome may cause post-TKA pain due to mechanical irritation. In this present case, a 64-year-old woman experienced lateral knee pain which was localized at the iliotibial ligament 8 years after the surgery. Fabella syndrome was diagnosed, and fabellectomy provided immediate resolution of the pain. The previous reports have revealed the symptoms occurred after 6 days to a year after total knee arthroplasty. This case widens the time span and the consideration of the fabella syndrome. The reason of this late onset symptom could be due to the enlargement of the fabella over time. We report that the differential diagnosis of fabella syndrome should be thought in symptoms of late onset knee pain after total knee arthroplasty.

Selective adsorption of 1,3-dimethyltrisulfane (DMTS) responsible for aged odour in Japanese sake using supported gold nanoparticles.

Gold (Au) nanoparticles (NPs) supported on SiO2 (Au/SiO2) were prepared by a practical impregnation method and applied as an adsorbent for 1,3-dimethyltrisulfane (DMTS), which is responsible for an unpleasant odour in drinks, especially Japanese sake. Compared with a conventional adsorbent, activated carbon, Au/SiO2 selectively reduced the DMTS concentration in Japanese sake without decreasing the concentrations of other aromatic components. DFT calculations revealed that the selective adsorption of DMTS occurred through the formation of a stable intermediate. The size of the supported Au NPs was controlled by the preparation conditions and determined from TEM observations and XRD measurements, and the size was ranged from 2.4 nm to 30 nm. Au/SiO2 having Au NPs with a diameter of 2.4 nm adsorbed DMTS the most efficiently. Smaller Au NPs showed better DMTS adsorption capabilities because larger amounts of Au atoms were exposed on their surfaces in the size range of this study. Langmuir-type monolayer adsorption and one-to-one binding of Au-S are proposed to occur based on an adsorption isotherm experiment. Even though significant differences of the fruity aroma score were not observed in the sensory evaluation between Au/SiO2 and activated carbon for this less aromatic Japanese sake, Au/SiO2 selectively decreased the DMTS concentration in the instrumental analysis.

Factors Affecting Longer Surgical Times in Total Knee Arthroplasty for Obese Patients-A Comparative Study between High- and Nonhigh-Volume Surgeons.

Obesity has a negative influence on surgical times in total knee arthroplasty (TKA). Our purpose in this multicenter study was to compare surgical times between high- (HV) and nonhigh-volume (NHV) surgeons and clarify the important factors affecting longer surgical times in primary TKA for obese patients. A total of 798 knees, average age 75.1 years, were enrolled. All TKAs were done using the same measured resection technique by 25 surgeons at 12 facilities and were divided into three groups based on body mass index (kg/m2) of the patients (Group A: <24.9, Group B: 25-29.9, Group C: ≥30). Operative techniques including four surgical steps (surgical exposure, bone cutting, trial and fixation of the permanent component, and wound closure) were evaluated both in HV and NHV surgeons. In classifying surgeon volume, HV surgeons had performed >100 TKAs annually for many years, and other surgeons who had performed <100 TKAs annually were defined as NHV surgeons. Patient demographics, surgical details, and surgical times in each phase were compared using nonrepeated measures of analysis of variance and a post hoc Student-Newman-Keuls test. A total of 331, 327, 140 TKAs were allocated to Groups A, B, C, respectively. Regarding patient demographics, patients in Group C were younger and had the worst ranges of motion. The longest surgical time was observed in Group C of NHV surgeons (p < 0.05). Concerning each surgical phase, surgeons took much more time in surgical exposure and fixation of the permanent component for obese patients in NHV surgeons (p < 0.05). Our results suggest that younger age and lower range of motion were observed in obese patients, which led to longer surgical times. In addition, NHV surgeons took much time in surgical exposure and fixation of the permanent component for obese patients, while surgical time was similar among groups for HV surgeons.

Late Somatic Gene 2 disrupts parental spheroids cooperatively with Volvox hatching enzyme A in Volvox.

MAIN CONCLUSION: We identified LSG2 as a novel lytic enzyme that accumulates in the parental extracellular matrix and disrupts parental spheroids cooperatively with VheA secreted by juveniles in Volvox. Spatiotemporally restricted degradation of extracellular matrix (ECM) is essential for development and survival in multicellular organisms. In an asexual life cycle of green algae Volvox, juveniles are released from parental spheroids through holes made by restricted degradation of parental ECM at the proper timing. Lytic enzyme(s) should specifically degrade parental ECM upon Volvox hatching, but little is known about the mechanisms of spatiotemporally restricted parental degradation. Here, we identified a glycoprotein encoded by the Late Somatic Gene 2 (LSG2) as a novel lytic enzyme that accumulates in parental ECM during the prehatching stages. The dual action of LSG2 and Volvox hatching enzyme A (VheA), a serine protease secreted by juveniles, causes the degradation of ECM sheets at all stages and destroys even daughter spheroids, while VheA alone disrupts spheroids only in the prehatching stage when LSG2 is accumulated, suggesting that the combination of LSG2 and VheA is sufficient to cause the degradation of ECM sheet. In the prehatching stage, parental spheroids became susceptible to the proteolysis by a mixture of bacterial proteases applied externally, which could be facilitated by LSG2. These results suggest that LSG2 disrupts parental ECM cooperatively with VheA by modifying the parental ECM to make it fragile, and that the appropriate activity of these enzymes is crucial for the parent-specific ECM degradation at the proper timing.

Multi-Walled Carbon Nanotube Growth in Multi-Walled Carbon Nanotubes by Chemical Vapor Deposition.

We report chemical vapor deposition (CVD) growth of a multi-walled carbon nanotube (MWCNT) inside another MWCNTs from a cementite (Fe3C) catalyst nanoparticles. The CNTs have bi or tri-layered core(s)-sheath structure with various crystallinity. The sheath grows first at a lower temperature, and then the catalyst nanoparticle works again to grow the core(s) at a higher temperature in the tip or root growth mode. Transmission electron microscopy (TEM) observation provides a clear piece of evidence of reverse-inward growth.

Flattened Multiwalled Carbon Nanotube with Multi-Layered Structure.

Fabrication of novel nanostructures based on carbon nanotubes has been a focus of recent interest since they are expected to inherit excellent properties of carbon nanotube. To find new nanotube-based nanostructures, it is important to find a new growth mode or process. This paper reports the formation of a multiwalled carbon nanotube that has bi-layered structure and is partly flattened. Transmission electron microscopy observations suggest that the outer multiwalled layer was formed first from a Fe catalyst nanoparticle, and was partly flattened during the growth. Then the catalyst nanoparticle worked again to form the inner multiwalled tube moving inside the outer tube and became flattened at the same position of the outer tube. It is likely that the inner growth gave an expansion stress against the flattened outer tube; nevertheless, the flattened part of the outer tube remained. This observation evidences that the flattening of the nanotube occurred simultaneously during the growth and was stabilized by structural defect.

Numerical Analysis of Organ Doses Delivered During Computed Tomography Examinations Using Japanese Adult Phantoms with the WAZA-ARI Dosimetry System.

A dosimetry system for computed tomography (CT) examinations, named WAZA-ARI, is being developed to accurately assess radiation doses to patients in Japan. For dose calculations in WAZA-ARI, organ doses were numerically analyzed using average adult Japanese male (JM) and female (JF) phantoms with the Particle and Heavy Ion Transport code System (PHITS). Experimental studies clarified the photon energy distribution of emitted photons and dose profiles on the table for some multi-detector row CT (MDCT) devices. Numerical analyses using a source model in PHITS could specifically take into account emissions of x rays from the tube to the table with attenuation of photons through a beam-shaping filter for each MDCT device based on the experiment results. The source model was validated by measuring the CT dose index (CTDI). Numerical analyses with PHITS revealed a concordance of organ doses with body sizes of the JM and JF phantoms. The organ doses in the JM phantoms were compared with data obtained using previously developed systems. In addition, the dose calculations in WAZA-ARI were verified with previously reported results by realistic NUBAS phantoms and radiation dose measurement using a physical Japanese model (THRA1 phantom). The results imply that numerical analyses using the Japanese phantoms and specified source models can give reasonable estimates of dose for MDCT devices for typical Japanese adults.

Anterior Cruciate Ligament Reconstruction Does Not Fully Restore Normal 3D Knee Kinematics at 12 Months During Walking and Walk-Pivoting: A Longitudinal Gait Analysis Study.

The purpose of the current study was to longitudinally evaluate how preoperative knee kinematics change after ACL reconstruction. Three-dimensional gait analysis using the point cluster method was undertaken on the same subjects preoperatively and at 3, 6, and 12 months after ACL reconstructive surgery. Thirteen subjects (7 males, 6 females) were examined while performing 2 different activities at self-selected speeds: walking and walk-pivoting (walking, pivoting toward the landed limb side and walking away). The contralateral knees of subjects at 12 months postoperatively were selected as control knees. Flexion range in the stance phase increased with time after surgery, but remained lower than in the contralateral knee, even at 12 months postoperatively (P < .05) during walking and walk-pivoting. The rotation pattern during walking and walk-pivoting showed an offset toward external rotation by 6 months postoperatively compared with control knees, while at 12 months postoperatively the offset had nearly disappeared and the movement pattern resembled that in control knees. These findings suggest that a return to sport participation by 6 months after ACL reconstruction requires careful consideration. Depending on the type of sport, activity restriction even after 12 months may need to be considered to allow complete kinematic restoration.