Single Breath Research Articles

Clinical Effects of Enhanced Recovery after Surgery in Perioperative Period Patients with Video-Assisted Thoracoscopic Lobectomy.

Enhanced recovery after surgery (ERAS) guidelines provide significant benefits for patients after surgery. Care bundles combine various evidence-based treatments and care measures for managing refractory clinical diseases. Therefore, we aimed to evaluate the ERAS measures and care bundles to reduce post-operative complications associated with video-assisted thoracic surgery (VATS) lobectomy and promote patients' recovery. As a retrospective study, this study included 120 non-small cell lung carcinoma patients, who were divided into a control group and an observation group according to the post-operative care methods of the patients in the medical record system. Among them, sixty patients, admitted from January 2018 to January 2019, were included in the control group, and 60 patients, admitted from January 2022 to January 2023, were included in the observation group. The control group received routine care (non-ERAS group), and the observation group followed the bundles of care strategy based on ERAS guidelines (ERAS group). Data collected included baseline characteristics, clinical parameters, and post-operative parameters of patients in the ERAS and non-ERAS groups. The clinical data of all patients came from the hospital medical record system. There were no significant differences in gender, age, tumor node metastasis (TNM) stages, smoking, and drinking between the ERAS and non-ERAS groups (p > 0.05). Similarly, no significant differences were observed in Cardiac Ejection fraction (≥50%), forced expiratory volume in 1 sec % (FEV1%) forced vital capacity (FVC), Lymphocyte, Neutrophils (%), and Tumor diameter between the ERAS and non-ERAS groups (p > 0.05). In contrast, significant differences were found in FVC, FEV1%, diffusing capacity of the lungs for carbon monoxide single breath (DLCO SB), Albumin, C-reactive protein, Leukocyte, Monocytes, Lymphocyte (%), Hemoglobin, and Neutrophils between the ERAS and non-ERAS groups (p < 0.05). Furthermore, Receiver Operating Characteristic (ROC) analysis indicated that Leukocytes, DLCO, C-reactive protein (CRP), FEV1%, Monocytes, Lymphocytes (%), Neutrophils (%), and Body Mass Index (BMI) were essential predictors of ERAS. Using cutoff values of Leukocytes >12.5, FEV1% >112.9, Monocytes >16.8 (109/L), and Neutrophils >11.6, patients undergoing VATS lobectomy were more likely to experience a quick recover. When ERAS measures integrated bundles of care, the extubation time can reduced to less than 5.5 days, the visual analogue scale (VAS) score to less than 3.5, and the post-operative hospital stay to less than 10.5 days. ERAS management measures based on bundles of care can significantly improve the prognosis of patients undergoing VATS lobectomy, reduce post-operative complications, and accelerate safe rehabilitation. Furthermore, they can greatly shorten hospital stays, lower overall healthcare costs, and alleviate social and family burdens. These significant differences may be related to factors such as Leukocytes, FEV1%, Monocytes, and Neutrophils.

Comparing in vitro nitric oxide blood uptake to its pulmonary diffusing capacity

Whether endothelium derived Nitric Oxide (NO) uptake by the blood is limited by a boundary layer, the red cell membrane or its interior is the subject of continued debate. Whether lung uptake of NO in the single-breath DLNO test is limited by blood or not is also debated. To understand which processes are limiting blood NO uptake we have modelled NO chemical kinetics and we have derived a shrinking core model, Thiele Modulus and FTCS (Euler) numerical solution. In a rapid reaction apparatus, NO uptake appears limited by a boundary layer, and throughout the red cell, by diffusion. In the single breath situation, and arguably with endogenous NO in vivo, NO uptake appears limited by a boundary layer and a pseudo first order chemical reaction in the outer molecular layers of the red cell. We have not found evidence to support red cell membrane limitation.

Stylising agency, identity and solidarities in South African English language classrooms

In a call for papers, the English Academy of Southern Africa (EASA) problematises what we perceive as the challenges of stylising agency, identity and solidarities in South African literature in English and English Language classroom encounters. The academy argues that speaking of literature and literacy in a single breath is to take for granted a linear relationship between literature and literacy. In interrogating ways of reading, this article contends that such proficiency is itself unstable and shifting, subject to different contexts and approaches inasmuch as these diverse ways are contingent upon material and technological changes. Literacy is a contested term: while it denotes the ability to read and write, a more nuanced understanding recognizes its capacity to confer value and influence aesthetic judgment. Already implicit in such an understanding is the mutually reinforcing relation between literature and literacy: the cognitive skillset which enables us to read is constantly being modified by what we read, and by the material forms which our reading takes. The entanglement of literature and literacy is embedded in cultures, compelling us to ask how particular teachers, writers and critical literary approaches shape our reading practices, our ways of seeing. The same entanglement generates questions about social justice, access to education, and material affordances.

Respiratory pressure and split flow data collection device with rapid occlusion attachment

Respiratory model-based methods require datasets containing enough dynamics to ensure model identifiability for development and validation. Rapid expiratory occlusion has been used to identify elastance and resistance within a single breath. Currently accepted practice for rapid expiratory occlusion involves a 100 ms occlusion of the expiratory pathway. This article presents a low-cost modular rapid shutter attachment to enable identification of passive respiratory mechanics. Shuttering faster than 100 ms creates rapid expiratory occlusion without the added dynamics of muscular response to shutter closure, by eliminating perceived expiratory blockage via high shutter speed. The shutter attachment fits onto a non-invasive venturi-based flow meter with separated inspiratory and expiratory pathways, established using one-way valves. Overall, these elements allow comprehensive collection of respiratory pressure and flow datasets with relatively very rapid expiratory occlusion.

Development and integration of a hierarchical Pd/WO3 acetone-sensing device for real-time exhaled breath monitoring with disposable face mask

This study introduces an inventive acetone-sensing device seamlessly integrated into a disposable face mask, enabling real-time continuous breath monitoring. The sensor demonstrates exceptional sensitivity, registering a response of 8.22 at 1 ppm and an impressive sensor response of 57.33 at 100 ppm of acetone concentration. Particularly noteworthy is the remarkable lower limit of detection (LOD) of 0.076 ppm within the concentration range of 0.1–0.8 ppm, underscored by a robust R2 value of 0.994. To validate practicality, the Pd/WO3 sensor was fabricated onto cellulose paper and utilized for real-time breath analysis, yielding a substantial sensor response of 1.70 at 8 vol% (equivalent to a single exhale breath volume). The unique design incorporates a built-in disposable face mask, facilitating dependable and convenient real-time breath analysis. Additionally, this research explores the profound impact of introducing acetone and Pd atoms on the energy levels and dipole moments. The species elucidated through density functional theory (DFT) investigations encompassing WO3, WO3-acetone, Pd-WO3, and Pd-WO3-acetone species. This work presents an innovative and cost-effective approach for developing a portable, non-invasive, and highly sensitive acetone-sensing device, effectively integrated into a disposable face mask for real-time breath analysis. This pioneering technology holds immense potential for various applications in healthcare and beyond.

Large animal ventilator-integrated volumetric capnography generates clinically acceptable values of physiologic dead space in anesthetized healthy adult horses.

To evaluate the agreement between the Tafonius large animal ventilator-integrated volumetric capnography (vCap) software and the Respironics NICO noninvasive cardiac output monitor reference system. Data were collected from 56 healthy adult horses undergoing general anesthesia. Animals were placed under general anesthesia and connected to the Tafonius large animal ventilator circle system. A flow partitioning device with CO2 and flow sensors was utilized to couple the endotracheal tube to the NICO monitor. Tafonius CO2 and flow sensors are incorporated into the Y-piece of the breathing circuit. Arterial blood samples were collected to determine the partial pressure of arterial carbon dioxide (PaCO2) immediately before data collection. The PaCO2 was input into the Tafonius and NICO monitor, and dead space ventilation (%Vd), end-tidal CO2 partial pressure (ETco2), mixed-expired CO2 partial pressure (Peco2), and expired tidal volume (Vt) were calculated over a single breath. Multiple measurements were completed for each patient, with a total of 200 paired data points collected for analysis. Data were assessed for normality, and Bland-Altman analysis was performed. Bias and 95% limits of agreement were calculated. The limits of agreement for %Vd of the ventilator-derived measurements fell within ± 10% of the NICO monitor reference method. Our results indicate that, when compared to the NICO monitor method, the Tafonius-integrated vCap software provides clinically acceptable values of Peco2, Vt, and %Vd in healthy adult horses.

Pulmonary Function Assessment in Myasthenia Gravis Patients in a National Referral Hospital in Indonesia.

Myasthenia gravis (MG) can cause respiratory muscle weakness and the need of ventilator support. Spirometry as the gold standard for pulmonary function examination has limited availability, especially in our hospital which is only available in outpatient clinic during work hours (not in emergency room or patient room). Furthermore, all primary healthcare in Indonesia do not have spirometry equipment, thus other alternatives are required. This study aimed to analyze the relationship between a single breath counting test (SBCT), peak flow meter (PFM), and spirometry to assess pulmonary function in MG patients in a national referral hospital in Indonesia. A single-center, cross-sectional study was conducted and SBCT, PFM, and spirometry examination were performed in MG patients and healthy controls. Seventy patients, aged 47.7 ± 13.4 years old, participated in this study. SBCT, forced vital capacity first second (FVC1), and forced expiratory volume first second (FEV1) value between MG patients and healthy controls showed a significant difference, in which healthy controls have higher SBCT, FVC1, and FEV1 values (p = 0.000, p = 0.000 and p = 0.001 respectively). There was a significant difference between PFM with SBCT and FVC1 value in MG patients. Strong correlation was found between SBCT and FVC1 in MG patients. MG patients had worse pulmonary function compared to healthy controls. SBCT and PFM examination have a significant correlation with FVC1 in MG patients. Therefore, SBCT and PFM can be used as a bedside tool to detect respiratory impairment in MG patients.

Radiation Induced Lung Injury in Rats after Pre-Oxygenation Radiotherapy

Deep inspiratory breath holding (DIBH) has been widely used during the radiotherapy of thoracic tumors. The main disadvantage of voluntary DIBH is the short duration of each breath hold. The hypocapnia induced by hyperoxia (oxygen concentration > 50%) pre-oxygenation (PreO2) combined with mechanical hyperventilation has been reported to prolong the duration of single breath hold, but its safety remains controversial, especially the sensitivity of lung tissue to radiation damage under hyperoxia exposure has not been elucidated. In this study, we aim to investigate the changes of radiation induced lung injury in rats after PreO2 radiation. We evaluated the lung tissue of rats at different time points (48h, 2w, 4w, 8w, 12w) after thoracic radiation (15Gy single fraction to the right lung), and sequenced the transcriptome of lung tissue at 48 hours after irradiation. Rat cohorts (n = 7/group): 1. Control (Con); 2. Radiation group (RT); 3. Pre-oxygenation (oxygen concentration > 90%) for 8 hours before thoracic radiation (PreO2). The inflammatory exudation emerged in the pulmonary interstitium at 48 hours, and reached the most serious alveolitis after four weeks of irradiation (the comparison of alveolitis scores in RT4w vs Con4w and PreO2(4w) vs Con4w, P<0.001) on hematoxylin-eosin staining. While the alveolitis scores in RT group and PreO2 group were not statistically different at each time point. Masson staining showed that the pulmonary fibrosis in the RT group and the PreO2 group reached an obvious pathological change at 12 weeks after irradiation, but the difference between the two groups was not significant. Transcriptome sequencing showed that the number of differential genes in PreO2 vs Con was 559 (302 up-regulated genes and 257 down-regulated genes). The GO enrichment analysis indicated that chromosome segregation was the most significant functional item with P value in the comparative analysis, and the KEGG enrichment analysis suggested that cell division was the most significant enrichment pathway of these differential genes. While there was a small quantity of differential genes in PreO2 vs RT group (3 up-regulated genes and 12 down-regulated genes). Pentose and glucuronate conversions were the most significant enrichment pathway of these differential genes. This study demonstrated that PreO2 radiotherapy did not increase the severity of radiation induced lung injury in rats compared to conventional radiotherapy. Further study should be conducted to confirm these results and to investigate the regulatory mechanism of pneumonia caused by PreO2 radiotherapy.

Comparison between compressed sensing and segmented cine cardiac magnetic resonance: a meta-analysis

PurposeHighly accelerated compressed sensing cine has allowed for quantification of ventricular function in a single breath hold. However, compared to segmented breath hold techniques, there may be underestimation or overestimation of LV volumes. Furthermore, a heterogeneous sample of techniques have been used in volunteers and patients for pre-clinical and clinical use. This can complicate individual comparisons where small, but statistically significant differences exist in left ventricular morphological and/or functional parameters. This meta-analysis aims to provide a comparison of conventional cine versus compressed sensing based reconstruction techniques in patients and volunteers.MethodsTwo investigators performed systematic searches for eligible studies using PubMed/MEDLINE and Web of Science to identify studies published 1/1/2010-3/1/2021. Ultimately, 15 studies were included for comparison between compressed sensing cine and conventional imaging.ResultsCompared to conventional cine, there were small, statistically significant overestimation of LV mass, underestimation of stroke volume and LV end diastolic volume (mean difference 2.65 g [CL 0.57–4.73], 2.52 mL [CL 0.73–4.31], and 2.39 mL [CL 0.07–4.70], respectively). Attenuated differences persisted across studies using prospective gating (underestimated stroke volume) and non-prospective gating (underestimation of stroke volume, overestimation of mass). There were no significant differences in LV volumes or LV mass with high or low acceleration subgroups in reference to conventional cine except slight underestimation of ejection fraction among high acceleration studies. Reduction in breath hold acquisition time ranged from 33 to 64%, while reduction in total scan duration ranged from 43 to 97%.ConclusionLV volume and mass assessment using compressed sensing CMR is accurate compared to conventional parallel imaging cine.

COVID-19 GEÇİRİP İYİLEŞMİŞ KİŞİLER VE KONTROLLERDE COVID-19 PANDEMİSİNİN FİZİKSEL VE SOSYAL ETKİLERİNİN KARŞILAŞTIRILMASI: BİR VAKA KONTROL ÇALIŞMASI

Purpose: To compare the fatigue and dyspnea level, respiratory function, mental fatigue, sleep quality, and social influence of the COVID-19 pandemic in convalescent and controls and to explore the relationship between these characteristics in both groups.&#x0D; Methods: A total of 352 participants, including COVID-19 convalescent (n=176) and controls (n=176), participated in this study. The following instruments were used by online technologies: Visual Analog Scale (VAS) to investigate fatigue and dyspnea level, Single Breath Counting (SBC) test to measure respiratory function, Wood Mental Fatigue Inventory (WMFI) to evaluate mental fatigue, Pittsburg Sleep Quality Index (PSQI) to assess the sleep quality and Social Influences Survey Questionnaire (SISQ) to investigate social influences of the pandemic. &#x0D; Results: COVID-19 convalescents reported higher levels of tiredness, dyspnea, and mental fatigue than controls (p

Estimation of transpulmonary driving pressure during synchronized mechanical ventilation using a single lower assist maneuver (LAM) in rabbits: a comparison to measurements made with an esophageal balloon

BackgroundMechanical ventilation is applied to unload the respiratory muscles, but knowledge about transpulmonary driving pressure (ΔPL) is important to minimize lung injury. We propose a method to estimate ΔPL during neurally synchronized assisted ventilation, with a simple intervention of lowering the assist for one breath (“lower assist maneuver”, LAM).MethodsIn 24 rabbits breathing spontaneously with imposed loads, titrations of increasing assist were performed, with two neurally synchronized modes: neurally adjusted ventilatory assist (NAVA) and neurally triggered pressure support (NPS). Two single LAM breaths (not sequentially, but independently) were performed at each level of assist by acutely setting the assist to zero cm H2O (NPS) or NAVA level 0 cm H2O/uV (NAVA) for one breath. NPS and NAVA titrations were followed by titrations in controlled-modes (volume control, VC and pressure control, PC), under neuro-muscular blockade. Breaths from the NAVA/NPS titrations were matched (for flow and volume) to VC or PC. Throughout all runs, we measured diaphragm electrical activity (Edi) and esophageal pressure (PES). We measured ΔPL during the spontaneous modes (PL_PES) and controlled mechanical ventilation (CMV) modes (PL_CMV) with the esophageal balloon. From the LAMs, we derived an estimation of ΔPL (“PL_LAM”) using a correction factor (ratio of volume during the LAM and volume during assist) and compared it to measured ΔPL during passive (VC or PC) and spontaneous breathing (NAVA or NPS). A requirement for the LAM was similar Edi to the assisted breath.ResultsAll animals successfully underwent titrations and LAMs for NPS/NAVA. One thousand seven-hundred ninety-two (1792) breaths were matched to passive ventilation titrations (matched Vt, r = 0.99). PL_LAM demonstrated strong correlation with PL_CMV (r = 0.83), and PL_PES (r = 0.77). Bland–Altman analysis revealed little difference between the predicted PL_LAM and measured PL_CMV (Bias = 0.49 cm H2O and 1.96SD = 3.09 cm H2O). For PL_PES, the bias was 2.2 cm H2O and 1.96SD was 3.4 cm H2O. Analysis of Edi and PES at peak Edi showed progressively increasing uncoupling with increasing assist.ConclusionDuring synchronized mechanical ventilation, a LAM breath allows for estimations of transpulmonary driving pressure, without measuring PES, and follows a mathematical transfer function to describe respiratory muscle unloading during synchronized assist.

Multisample Ultrasound Point Shear Wave Elastography of the Liver: Repeatability and Agreement With Conventional Point Shear Wave Elastography.

To characterize the technical performance of a multisample ultrasound point shear wave elastography (pSWE) technique that allows 15 individual measurements of liver stiffness in a single acquisition. In 56 overweight and obese adults, research ultrasound examinations were performed using conventional pSWE and multisample pSWE (Sequoia; Siemens Healthineers). Five independent measurements were acquired with the conventional technique over five consecutive breath holds (5C1 and DAX transducers). A single multisample acquisition (DAX transducer) of up to 15 unique measurements was acquired during a single breath hold. All imaging was performed before (baseline) and after a "coffee break" (repeat). Median liver stiffness measurements between techniques and between baseline and repeat imaging were compared using Pearson correlation (r) and intra-class correlation (ICC) coefficients. Mean participant age was 33.7 ± 11.4 years; 40 participants were female. There was high correlation between conventional pSWE measurements obtained using the 5C1 and DAX transducers at baseline (r = .75 [95% CI: 0.61-0.85], P < .0001) and repeat (r = .88 [95% CI: 0.78-0.92], P < .0001). There was moderate agreement between conventional pSWE measurements obtained using the 5C1 and DAX transducers at baseline (ICC = 0.69 [95% CI: 0.52-0.81]), and good agreement at repeat (ICC = 0.81 [95% CI: 0.65-0.90]). There was moderate correlation (r = .59 [95% CI: 0.39-0.74], P < .0001) and moderate agreement (ICC = 0.58 [95% CI: 0.38-0.73]) between baseline conventional and multisample pSWE measurements acquired using the DAX transducer; there was high correlation (r = .73 [95% CI: 0.57-0.83], P < .0001) and moderate agreement (ICC = 0.72 [95% CI: 0.56-0.82] between techniques at repeat. There was moderate correlation (r = .65 [95% CI: 0.46-0.78], P < .0001) and moderate agreement (ICC = 0.64 [95% CI: 0.45-0.77]) between baseline and repeat multisample pSWE measurements. Multisample pSWE, allowing up to 15 measurements in a single breath hold, showed moderate to high correlation and moderate agreement with conventional pSWE.

The added value of haemoglobin to height, age, and sex to predict DLCO in subjects with preserved exercise capacity.

The single breath diffusion capacity for carbon monoxide (DLCO) captures several aspects of the role of the lung in meeting the metabolic demands of the body. The magnitude of the independent contributors to the DLCO is unknown. The aim of this study was to investigate the factors that independently contribute to the DLCO. The objective was to investigate the impact of height, age, sex and haemoglobin on DLCO, alveolar volume (VA) and carbon monoxide transfer coefficient (KCO). Study participants were pre-screened based on normal exercise capacity achieved during an incremental cardio-pulmonary exercise testing (CPET) using cycle ergometry at McMaster University Medical Center between 1988-2012. Participants who had an FEV1>80% predicted, with an FEV1/FVC ≥0.7 and who achieved a maximum power output ≥80% were selected for analysis. In total, 16,298 subjects [61% male, mean height 1.70m (range 1.26-2.07), age 49 yrs (10-94), weight 79 kg (23-190) had DLCO measured while demonstrating normal spirometry and exercise capacity. The DLCO increased exponentially with height, was 15% greater in males, increased with age yearly until 20, then decreased yearly after the age of 35, and was 6% higher per gram of haemoglobin (5.58*Height(m)1.69*1.15 in Males*(1-0.006*Age>35)*(1+0.01*Age<20) *(1+0.06*Hb gm/dl), (r = 0.76). Height, age, sex, and haemoglobin all have independent influence on the DLCO in subjects with normal spirometry and preserved exercise capacity.

MRI and Pulmonary Function Tests' Results as Ventilation Inhomogeneity Markers in Children and Adolescents with Cystic Fibrosis.

Magnetic resonance imaging (MRI) of the chest is becoming more available in the detection and monitoring of early changes in lung function and structure in patients with cystic fibrosis (CF). The aim of this study was to assess the relationship between pulmonary function tests (PFT) and perfusion deficits in CF children measured by MRI. We performed a retrospective analysis of the perfusion lung MRI scans and the results of spirometry, oscillometry, body plethysmography, single-breath carbon monoxide uptake, and multiple-breath washout technique (MBW). There were statistically significant correlations between the MRI perfusion scores and MBW parameters (2.5% LCI, M1/M0, M2/M0), spirometry parameters (FEV1, FVC, FEF25/75), reactance indices in impulse oscillometry (X5Hz, X10Hz), total lung capacity (TLC) measured in single breath carbon monoxide uptake, markers of air-trapping in body plethysmography (RV, RV/TLC), and the diffusing capacity of the lungs for carbon monoxide. We also observed significant differences in the aforementioned PFT variables between the patient groups divided based on perfusion scores. We noted a correlation between markers of functional lung deficits measured by the MRI and PFTs in CF children. MRI perfusion abnormalities were reflected sooner in the course of the disease than PFT abnormalities.

A Pilot Study “To Derive the Normal Values of Single Breath Count in Young Healthy Adults”

Introduction: Pulmonary function tests such as spirometer and peak expiratory flow rate are the standard measuresto test lung volumes and capacities; but generally there is a lack of such equipment in emergency departments.Hence there is a need for an easier, quicker and convenient outcome measure in such set-ups. Single breath count(SBC) can be a simple assessment method in such clinical settings. However no studies for normal values of SBCin young Healthy adults were found during the search for literature.Objective: The objective of this study was to estimate normal value of SBC in Healthy young adult population.Results: 100 participants were enrolled from 18-24 years of age in the study. The mean SBC was 39(±7) and 41(±9)in females and males respectively. The SBC had a significant positive correlation with age at r=0.3, p value 0.0051and height at r=0.28, p value 0.0038. The SBC had a non-significant negative correlation with BMI and weight.Discussion: The results show that SBC was influenced significantly by gender (males&gt;females), age and height ofthe individuals. However BMI and weight did not seem to influence the SBC.Conclusion: SBC is a test which is easy to perform and appears to correlate well with standard measures ofpulmonary functions. We estimated the normal values of SBC in young healthy adults which can be used in theclinical set up.

Assessment of prognostic value of heart rate response to single deep breath in cases of acute myocardial infarction involving anterior wall or inferior wall within first 12 hours of admission

Introduction: The sympatho-vagal balance on the SA node produces beat to beat variation in heart rate which is markedly increased in normal subjects on deep breathing cycles. Heart rate variability testing gives an estimation of altered vagal-sympathetic balance and is a marker of low vagal tone on the heart. This study assesses a simple bedside test involving a single cycle of deep breathing to assess heart rate variability response. Methods: A prospective observational study was done from May 2018 to September 2018 in the department of cardiology in 52 subjects diagnosed as suffering from acute myocardial infarction. For this test, ECG recording in all limb leads was taken while the patient was asked to perform deep breathing for ten seconds. The difference between the maximum and minimum R-R interval was recorded as an index of heart rate variability. The patient was then followed up till discharge for improvement or deterioration in clinical condition. Results: Forty-one subjects (78.8%) had a heart variability response of less than 10 beats per minute and the rest eleven (20.2%) individuals had a variability response of &gt;10 beats per minute. Patients who had low heart rate variability (n=41) showed higher incidence of acute left ventricular failure (75%), arrhythmia (17.5%) as compared to patients who had normal heart rate variability. Conclusions: This test can serve as an inexpensive, feasible and bedside alternative to conventional methods and can be correlated with negative prognosis in patients with acute MI.

Characterization of Breath Sensor at Different Frequencies in Outdoor Condition

This paper investigates a breath sensor device that is designed to detect the moisture in human bulk matrix in outdoor conditions. The human bulk matrix is rich in moisture and carbon dioxide apart from the 872 volatile organic compounds emanating from the human breath. Human breathing effort is a respiration process that involves inhalation and exhalation modes. The human bulk matrix is a product of the latter. Most research in human breath analysis is concentrating on both human bulk matrix and breathing pattern. The aim of this study is to characterize the fabricated breath sensor at different input wave frequencies in the outdoor environment. In this study, an outdoor experiment was carried out using the breath sensor device that is connected to the input waveform from the frequency generator and the output reading is captured using the oscilloscope. A single exhaled breath originated from the human subject is required to activate the breath sensor. This method is easier and simpler, and the output wave result is generated by an oscilloscope in real-time. The result indicates that the investigated breath sensor is suitable for clinical and healthcare monitoring. Early studies indicate that the breath sensor can diagnose diseases related to breathing problems such as sleep apnoea, asthma, and strokes.

Lack of Association between Diaphragm Thickening Fraction and Transdiaphragmatic Pressure Swing in COVID-19 Pneumonia during Helmet Continuous Positive Airway Pressure: Research Letter.

Recently, evaluation of the diaphragm by means of ultrasound has become popular.1 The increase in diaphragm thickness during inspiration (thickening fraction) has been proposed as a noninvasive bedside measure of diaphragm function,2,3 although previous studies have reported wide variability between thickening, inspiratory effort, and transdiaphragmatic pressure.4–6 We hypothesized that the force-length and force-generating relationship in the diaphragm is altered by different positive end-expiratory pressure (PEEP) levels in patients with SARS-CoV-2.7We investigated the relationship between diaphragm thickening fraction and transdiaphragmatic pressure swing during noninvasive helmet continuous positive airway pressure. From March to December 2021, a total of 26 consecutive patients with laboratory-confirmed SARS-CoV-2 infection admitted to the intensive care unit of Santa Chiara Hospital (Trento, Italy) were prospectively enrolled. The study was approved by the ethics committee (Rep. Int. 282/2022), and written informed consent was obtained. At intensive care unit admission, according to the local protocol, noninvasive respiratory assistance with helmet continuous positive airway pressure was started, and a nasogastric tube provided with two balloons for registering the esophageal and gastric pressures was inserted.8 Intragastric positioning of the tube was checked with standard methods; both balloons were inflated with manufacturer- recommended volume. Intragastric position of the lower balloon was confirmed by positive pressure deflections during gentle abdominal compressions; the mid-lower third esophageal position of the proximal balloon was confirmed by inspiratory negative deflections and the presence of cardiac artifacts. In vivo calibration of the filling volume was performed. Patients underwent a trial with three increasing levels of PEEP, lasting 30 min each. The first level was set at 0 cm H2O. PEEP was then increased to 5 and 10 cm H2O; fractional expired oxygen tension was left unchanged. An average of three measurements was made, with careful attention to select the same breaths for the diaphragm ultrasound and for esophageal/gastric pressure measurements. During the last 5 min of each step, esophageal and transdiaphragmatic pressure swing and diaphragmatic ultrasound were recorded. The right hemidiaphragm was identified in the zone of apposition as a three-layered structure by B-mode ultrasonography, with the probe at the mid-axillary line at the 10th intercostal space.1 Thickness was measured from frozen M-mode images as the distance from the pleural to the peritoneal line. All the examinations were performed by the same expert physician and recorded for a subsequent offline analysis.The study population had a median age of 67.5 [62.3–72.5 interquartile range] yr, 16 (61.5%) were male, body mass index was 27 [24–33 interquartile range] kg/m2, and Pao2/fractional expired oxygen tension ratio and Paco2 at admission were 122 [103–139 interquartile range] and 39 [37–44 interquartile range] mmHg, respectively. No association was found between diaphragm thickening fraction and transdiaphragmatic pressure swings or esophageal pressure swings, at 0 cm H2O, 5 cm H2O, and 10 cm H2O (fig. 1).In a previous investigation, Steinberg et al.9 found that neither thickening fraction nor diaphragmatic excursion was able to estimate esophageal pressure swings in patients with SARS-CoV-2. We sought to extend these findings by investigating the relationship between diaphragm ultrasound and the transdiaphragmatic pressure swing, which should be more representative of the contribution of the diaphragm to the total inspiratory effort. Similar to other authors,4 we confirm the lack of association between diaphragm thickening and the transdiaphragmatic pressure. Despite that it may lie on the nonlinear pressure–volume relationship of the diaphragm, during a single breath, the diaphragm inspiratory thickening and the transdiaphragmatic pressure generated depend on the specific pattern of thoracoabdominal motion (i.e., a descent of the diaphragm rather than expansion of the rib cage). The application of PEEP also causes changes in the diaphragm geometry also modifying the force generated by the diaphragm that may not be uniform across the muscle.The different position of the diaphragm muscle over its force or length relationship is likely explained by changes in end-expiratory lung volume during the PEEP trial. Although not directly measured, diaphragm dysfunction can also be a contributing factor; COVID-19 is associated with a viral myositis,10 which might have affected diaphragm force-generating capacity.However, the impact of the small sample size on any statistical inference must be considered, and the lack of Gilbert index and pressure-time product of diaphragmatic pressure calculation reduces the interpretation of our results.In summary, despite being promising for its feasibility and noninvasive characteristics, the assessment of diaphragm thickening should not be used as a surrogate for inspiratory effort. In SARS-CoV-2 patients during helmet continuous positive airway pressure in the acute setting, an increase in inspiratory effort, as measured by transdiaphragmatic pressure swings, is not related to diaphragm thickening fraction. We suggest caution against using this tool to inform clinical choices about respiratory support, at least until more robust data will be available.Support was provided solely from institutional and/or departmental sources.The authors declare no competing interests.

Comparison of Pre-oxygenation with Single Vital Capacity Breath Technique and Tidal Volume Breathing Technique for Adult Patients Undergoing General Anaesthesia

Background: Pre-oxygenation before induction of general anaesthesia is widely used for enhancing oxygen reserves and preventing hypoxia. Several techniques for pre-oxygenation have been described. This study was designed to compare the PaO2 and ETO2 with single vital capacity breath technique (SVCB) and tidal volume breathing technique (TVB) for adult patients undergoing general anaesthesia.&#x0D; Methods: Fifty patients were pre-oxygenated with both techniques - first SVCB then TVB separated by five minutes of breathing room air or till ETO2 &amp; PaO2 values reached baseline values (whichever was later). ABG samples &amp; ETO2 readings were taken before pre-oxygenation &amp; every thirty seconds for three minutes in both techniques.&#x0D; Results: Pre-test, mean PaO2 and ETO2 values of both techniques (SVCB and TVB) were similar. In SVCB technique, the mean PaO2 (mmHg) and ETO2 (%) significantly increased at 30 seconds (p ≤ 0.001) from 95.26 and 17.14 (pre-test time) to 304.34 and 92.48 respectively. In TVB technique, an exponential increase was noted. The mean PaO2 (mmHg) and ETO2(%) significantly increased at 180 seconds (p ≤ 0.001) from 96.26 and 16.26 (pre-test time) to 305.64 and 93.08 respectively. Peak values of oxygenation in both groups were similar but achieved at different time points.&#x0D; Conclusion: SVCB technique achieves high oxygenation rapidly but is not sustained thus can be used for rapid sequence induction though not recommended for difficult airway scenarios. TVB technique also achieves high oxygenation but steadily. TVB may be used for induction, including, rapid sequence induction but after 3-5 minutes of pre-oxygenation.

A hybrid model- and deep learning-based framework for functional lung image synthesis from multi-inflation CT and hyperpolarized gas MRI.

Hyperpolarized gas MRI is a functional lung imaging modality capable of visualizing regional lung ventilation with exceptional detail within a single breath. However, this modality requires specialized equipment and exogenous contrast, which limits widespread clinical adoption. CT ventilation imaging employs various metrics to model regional ventilation from non-contrast CT scans acquired at multiple inflation levels and has demonstrated moderate spatial correlation with hyperpolarized gas MRI. Recently, deep learning (DL)-based methods, utilizing convolutional neural networks (CNNs), have been leveraged for image synthesis applications. Hybrid approaches integrating computational modeling and data-driven methods have been utilized in cases where datasets are limited with the added benefit of maintaining physiological plausibility. To develop and evaluate a multi-channel DL-based method that combines modeling and data-driven approaches to synthesize hyperpolarized gas MRI lung ventilation scans from multi-inflation, non-contrast CT and quantitatively compare these synthetic ventilation scans to conventional CT ventilation modeling. In this study, we propose a hybrid DL configuration that integrates model- and data-driven methods to synthesize hyperpolarized gas MRI lung ventilation scans from a combination of non-contrast, multi-inflation CT and CT ventilation modeling. We used a diverse dataset comprising paired inspiratory and expiratory CT and helium-3 hyperpolarized gas MRI for 47 participants with a range of pulmonary pathologies. We performed six-fold cross-validation on the dataset and evaluated the spatial correlation between the synthetic ventilation and real hyperpolarized gas MRI scans; the proposed hybrid framework was compared to conventional CT ventilation modeling and other non-hybrid DL configurations. Synthetic ventilation scans were evaluated using voxel-wise evaluation metrics such as Spearman's correlation and mean square error (MSE), in addition to clinical biomarkers of lung function such as the ventilated lung percentage (VLP). Furthermore, regional localization of ventilated and defect lung regions was assessed via the Dice similarity coefficient (DSC). We showed that the proposed hybrid framework is capable of accurately replicating ventilation defects seen in the real hyperpolarized gas MRI scans, achieving a voxel-wise Spearman's correlation of 0.57±0.17 and an MSE of 0.017±0.01. The hybrid framework significantly outperformed CT ventilation modeling alone and all other DL configurations using Spearman's correlation. The proposed framework was capable of generating clinically relevant metrics such as the VLP without manual intervention, resulting in a Bland-Altman bias of 3.04%, significantly outperforming CT ventilation modeling. Relative to CT ventilation modeling, the hybrid framework yielded significantly more accurate delineations of ventilated and defect lung regions, achieving a DSC of 0.95 and 0.48 for ventilated and defect regions, respectively. The ability to generate realistic synthetic ventilation scans from CT has implications for several clinical applications, including functional lung avoidance radiotherapy and treatment response mapping. CT is an integral part of almost every clinical lung imaging workflow and hence is readily available for most patients; therefore, synthetic ventilation from non-contrast CT can provide patients with wider access to ventilation imaging worldwide.