Breathing Bag Research Articles

Sterilization and reuse of masks for a standardized exhaled breath collection device by autoclaving

Exhaled breath research has been hindered by a lack of standardization in collection and analysis methodologies. Recently, the Respiration Collector for In Vitro Analysis (ReCIVA) sampling device has illustrated the potential to provide a consistent and convenient method for exhaled breath collection onto adsorbent media. However, the significant costs, compared to exhaled breath bags, associated with the standardized collector is believed to be the reason for limited widespread use by researchers in the exhaled breath field. For example, in addition to the sampling hardware, a single-use disposable silicon mask affixed with a filter is required for each exhaled breath collection. To reduce the financial burden, streamline device upkeep, reduce waste material, and ease the logistical burden associated with the single use masks, it is hypothesized that the consumable masks and filters could be sterilized by autoclaving for reuse. The masks were contaminated, autoclaved, and then tested for any surviving pathogens with spore strip standards and by measuring the optical density of cultures. The compound background collected when using the ReCIVA with new masks was compared to that collected with repeatedly autoclaved masks via thermal desorption gas chromatography mass spectrometry (TD-GC-MS). The capacity to block particulate matter of new filters was tested against that of autoclaved filters by introducing an aerosol and comparing pre-filter and post-filter particle counts. Finally, breath samplings were conducted with new masks and autoclaved masks to test for changes in measurements by TD-GC-MS of exogenous and endogenous compounds. The data illustrate the autoclave cycle sterilizes masks spiked with saliva to background levels (p = 0.2527). The results indicate that background levels of siloxane compounds are increased as masks are repetitively autoclaved. The data show that mask filters have significant breakthrough of 1 μm particles after five repetitive autoclaving cycles compared to new filters (p = 0.0219). Finally, exhaled breath results utilizing a peppermint ingestion protocol indicate two compounds associated with peppermint, menthone and 1-Methyl-4-(1-methylethyl)-cyclohexanol, and an endogenous exhaled breath compound, isoprene, show no significant difference if sampled with a new mask or a mask autoclaved five times (p > 0.1063). Collectively, the data indicate that ReCIVA masks and filters can be sterilized via autoclave and reused. The results suggest ReCIVA mask and filter reuse should be limited to three times to limit potentially problematic background contaminants and filter dysfunction.

Exhaled VOCs can discriminate subjects with COVID-19 from healthy controls

COVID-19 detection currently relies on testing by reverse transcription polymerase chain reaction (RT-PCR) or antigen testing. However, SARS-CoV-2 is expected to cause significant metabolic changes in infected subjects due to both metabolic requirements for rapid viral replication and host immune responses. Analysis of volatile organic compounds (VOCs) from human breath can detect these metabolic changes and is therefore an alternative to RT-PCR or antigen assays. To identify VOC biomarkers of COVID-19, exhaled breath samples were collected from two sample groups into Tedlar bags: negative COVID-19 (n = 12) and positive COVID-19 symptomatic (n = 14). Next, VOCs were analyzed by headspace solid phase microextraction coupled to gas chromatography-mass spectrometry. Subjects with COVID-19 displayed a larger number of VOCs as well as overall higher total concentration of VOCs (p < 0.05). Univariate analyses of qualified endogenous VOCs showed approximately 18% of the VOCs were significantly differentially expressed between the two classes (p < 0.05), with most VOCs upregulated. Machine learning multivariate classification algorithms distinguished COVID-19 subjects with over 95% accuracy. The COVID-19 positive subjects could be differentiated into two distinct subgroups by machine learning classification, but these did not correspond with significant differences in number of symptoms. Next, samples were collected from subjects who had previously donated breath bags while experiencing COVID-19, and subsequently recovered (COVID Recovered subjects (n = 11)). Univariate and multivariate results showed >90% accuracy at identifying these new samples as Control (COVID-19 negative), thereby validating the classification model and demonstrating VOCs dysregulated by COVID are restored to baseline levels upon recovery.

Memsorb™, a novel CO2 removal device part I: in vitro performance with the Zeus IE®.

Soda lime-based CO2 absorbents are safe, but not ideal for reasons of ecology, economy, and dust formation. The Memsorb™ is a novel CO2 removal device that uses cardiopulmonary bypass oxygenator technology instead: a sweep gas passes through semipermeable hollow fibers, adding or removing gas from the circle breathing system. We studied the in vitro performance of a prototype Memsorb™ used with a Zeus IE® anesthesia machine when administering sevoflurane and desflurane in O2/air mixtures. The Zeus IE® equipped with Memsorb™ ventilated a 2L breathing bag with a CO2 inflow port in its tip. CO2 kinetics were studied by using different combinations of CO2 inflow (VCO2), Memsorb™ sweep gas flow, and Zeus IE® fresh gas flow (FGF) and ventilator settings. More specifically, it was determined under what circumstances the inspired CO2 concentration (FICO2) could be kept < 0.5%. O2 kinetics were studied by measuring the inspired O2 concentration (FIO2) resulting from different combinations of Memsorb™ sweep gas flow and O2 concentrations, and Zeus IE® FGFs and O2 concentrations. Memsorb™'s sevoflurane and desflurane waste was determined by measuring their injection rates during target-controlled closed-circuit anesthesia (TCCCA), and were compared to historical controls when using a soda lime absorbent (Draegersorb 800+) under identical conditions. With 160mL/min VCO2 and 5 L/min minute ventilation (MV), lowering the sweep gas flow at any fixed Zeus IE® FGF increased FICO2 in a non-linear manner. Sweep gas flow adjustments kept FICO2 < 0.5% over the entire Zeus IE® FGF range tested with VCO2 up to 280mL/min; tidal volume and respiratory rate affected the required sweep gas flow. At 10 L/min MV and low FGF (< 1.5 L/min), even a maximum sweep flow of 43 L/min was unable to keep FICO2 ≤ 0.5%. When the O2 concentration in the Zeus IE® FGF and the Memsorb™ sweep gas flow differed, FIO2 drifted towards the sweep gas O2 concentration, and more so as FGF was lowered; this effect was absent once FGF > minute ventilation. During sevoflurane and desflurane TCCCA, the Zeus IE® FGF remained zero while agent usage per % end-expired agent increased with increasing end-expired target agent concentrations and with a higher target FIO2. Agent waste during target-controlled delivery was higher with Memsorb™ than with the soda lime product, with the difference remaining almost constant over the FGF range studied. With a 5 L/min MV, Memsorb™ successfully removes CO2 with inflow rates up to 240mL/min if an FICO2 of 0.5% is accepted, but at 10 L/min MV and low FGF (< 1.5 L/min), even a maximum sweep flow of 43 L/min was unable to keep FICO2 ≤ 0.5%. To avoid FIO2 deviating substantially from the O2 concentration in the fresh gas, the O2 concentration in the fresh gas and sweep gas should match. Compared to the use of Ca(OH)2 based CO2 absorbent, inhaled agent waste is increased. The device is most likely to find its use integrated in closed loop systems.

Studies on Packaging and Storage of Green Capsicum (Cv. Indra) at Different Storage Conditions

The effect of different packaging materials along with two storage conditions i.e. Zero Energy Cool Chamber (ZECC) and Cold Storage (CS) were assessed for maintaining quality attributes and extending shelf life of green capsicum. The qualities of capsicums were assessed by physiological loss in weight, firmness, rotting, ascorbic acid and moisture content. The green capsicum fruits in all the treatments showed increasing trends of physiological loss in weight (%), TSS (°B) and rotting (%) while in moisture content, ascorbic acid (mg 100-1 g) and firmness (N) showed decreasing trend during the advancement of storage period in ZECC and CS. The quality of capsicum fruits of green varieties under CS and ZECC were found to be best when packed in cellulose acetate (CA) film followed by breathing bags. The shelf life of green capsicum fruits was extended up to 40 days in CS, 24 days in ZECC when packed in CA film followed by breathing bags and was found to be beneficial in extending the shelf life of capsicum fruits. The green capsicum packed in CA films was found to be best packaging material for extending the shelf life followed by breathing bags and without vent polythene bags of 100 micron, 50 micron and 25 micron, in CS and ZECC storage in respect of quality parameters.

The oral 13C-bicarbonate technique for determination of energy expenditure in dogs: dietary and environmental factors affecting the respiratory quotient and 13C recovery factor

ABSTRACT The oral 13C-bicarbonate technique (o13CBT) can be used for short-term measurements of CO2 production (RCO2) and energy expenditure (EEx). The method relies on appropriate estimates for the respiratory quotient (RQ) and recovery factor (RF) of 13C. Four Retriever dogs were included in four experiments to validate the o13CBT against indirect calorimetry (IC), and determine RQ and RF; Expt. 1: feeding different protein:fat:carbohydrate ratios [in % of metabolisable energy]: 25:33:42 in a maintenance (Mnt.) diet; 38:26:36 in a high-protein high-fibre (HFibre) diet and 27:56:17 in a high-fat (HFat) diet, simultaneously with start of measurements (T0); Expt. 2: the Mnt. diet at T0 or 4 h postprandial (T4); Expt. 3: T4 at different ambient temperatures, 22°C and 15°C; Expt. 4: T4 after 1 h physical activity. The RCO2 and EEx were determined from the respiration chamber measurements made simultaneously with IC and the o13CBT (o13CBTonline), and in Expts. 1 and 2, also on two consecutive days using o13CBT with collection of breath into breath bags (o13CBTbreathbags). The RQ values obtained at T0 reflected dietary compositions, with the highest least square mean (LSM) of 0.954 for the Mnt. diet, 0.905 for the HFibre and 0.877 for the HFat diet (p < 0.05). An increased interval between meal and measurement period decreased RQ significantly (p < 0.05) in Expt. 2, LSM being 0.954 at T0 and 0.909 at T4. Ambient temperature (Expt. 3) and physical activity (Expt. 4) did not influence postprandial RQ. The RF values were not significantly affected by diet (Expt. 1). Measurements starting at T0 (Expt. 2) resulted in higher (p < 0.05) RF values than at T4 (LSM = 0.971 and 0.836, respectively). The ambient temperatures (Expt. 3) did not influence postprandial RF. However, when dogs were physically active prior to measurements (Expt. 4), RF values (LSM = 1.019) were higher (p < 0.05) than when resting only (LSM = 0.836). Calculations based on RQ and RF determined in each experiment resulted in RCO2 and EEx values which were not different regardless of method used, except for Expt. 1 where EEx-values [kJ · kg BW–0.75 · d–1] were higher (p < 0.05) when measured with o13CBTbreathbags (460) than by IC (421) and o13CBTonline (420). Provided accurate RQ and RF values, the o13CBTbreathbags can be used as an independent and minimally invasive research tool to determine EEx in dogs under carefully standardised conditions.

Exhaled nitric oxide detection for diagnosis of COVID-19 in critically ill patients.

COVID-19 may present with a variety of clinical syndromes, however, the upper airway and the lower respiratory tract are the principle sites of infection. Previous work on respiratory viral infections demonstrated that airway inflammation results in the release of volatile organic compounds as well as nitric oxide. The detection of these gases from patients' exhaled breath offers a novel potential diagnostic target for COVID-19 that would offer real-time screening of patients for COVID-19 infection. We present here a breath tester utilizing a catalytically active material, which allows for the temporal manifestation of the gaseous biomarkers' interactions with the sensor, thus giving a distinct breath print of the disease. A total of 46 Intensive Care Unit (ICU) patients on mechanical ventilation participated in the study, 23 with active COVID-19 respiratory infection and 23 non-COVID-19 controls. Exhaled breath bags were collected on ICU days 1, 3, 7, and 10 or until liberation from mechanical ventilation. The breathalyzer detected high exhaled nitric oxide (NO) concentration with a distinctive pattern for patients with active COVID-19 pneumonia. The COVID-19 "breath print" has the pattern of the small Greek letter omega (). The "breath print" identified patients with COVID-19 pneumonia with 88% accuracy upon their admission to the ICU. Furthermore, the sensitivity index of the breath print (which scales with the concentration of the key biomarker ammonia) appears to correlate with duration of COVID-19 infection. The implication of this breath tester technology for the rapid screening for COVID-19 and potentially detection of other infectious diseases in the future.

Independent Lung Ventilation-Experimental Studies on a 3D Printed Respiratory Tract Model.

Independent lung ventilation (ILV) is a life-saving procedure in unilateral pulmonary pathologies. ILV is underused in clinical practice, mostly due to the technically demanding placement of a double lumen endotracheal tube (ETT). Moreover, the determination of ventilation parameters for each lung in vivo is limited. In recent years, the development of 3D printing techniques enabled the production of highly accurate physical models of anatomical structures used for in vitro research, considering the high risk of in vivo studies. The purpose of this study was to assess the influence of double-lumen ETT on the gas transport and mixing in the anatomically accurate 3D-printed model of the bronchial tree, with lung lobes of different compliances, using various ventilation modes. The bronchial tree was obtained from Respiratory Drug Delivery (RDD Online, Richmond, VA, USA), processed and printed by a dual extruder FFF 3D printer. The test system was also composed of left side double-lumen endotracheal tube, Siemens Test Lung 190 and anesthetic breathing bag (as lobes). Pressure and flow measurements were taken at the outlets of the secondary bronchus. The measured resistance increased six times in the presence of double-lumen ETT. Differences between the flow distribution to the less and more compliant lobe were more significant for the airways with double-lumen ETT. The ability to predict the actual flow distribution in model airways is necessary to conduct effective ILV in clinical conditions.

140 Measuring gastric emptying in horses with the 13C-acetate breath test when changing feeding order

Feeding order of oats and forage may influence the rate of gastric emptying (GE), but knowledge of GE is limited as it can be challenging to measure. The 13 C-acetate breath test (ABT) has been suggested as a minimally invasive way to measure GE using spot samples of breath air. The objective of this study was to determine the effect of feeding order of oats and forage on GE in horses. It was hypothesized that feeding oats before forage increases the rate of GE of oats as compared with feeding oats after forage. Four adult horses (15–24 yr) were used in this 2 × 2 crossover study, with 2 periods of 12 d. Each period consisted of a 10 d diet adaptation and 2 d sampling. Horses were fed the same amount of oats (470g dry matter (DM)) and forage (6900g DM) per day. Forage was fed 3 times per day (06, 14 and 20h), while oats were only fed in the morning either before or after forage. On d 2 of sampling, oats were mixed with 1g of 13 C-acetate. Before feeding oats, 3 baseline samples of exhaled breath air were taken. After feeding oats, a total of 12 samples were taken every half hour for 4 h, and then every hour until 8 h after administration of 13 C-acetate. Exhaled breath was collected in 1L breath bags using a mask connected to a 2-way non-rebreathing valve system. The mask covered one of the nostrils and a breath sample was taken within 30s. The breath bags were analyzed for 13 C-enrichment of CO 2 by means of an infrared isotope analyzer. The 13 C excretion curve (% dose recovered/h), was plotted using the formula y = a tb e −ct where y is the exhaled 13 C per hour in % of the dose (PDR, %/h), t is time (h) and a, b and c are regression constants. Half dose recovery time (T 1/2 ) was calculated from the area under the fitted cumulative 13 C excretion curve using the Excel function Gammainv (0.5;b+1;1/c), and time of peak excretion (T max ) was calculated as b/c. The effect of feeding order was compared using PROC mixed in SAS and considered significant if P < 0.05. The results indicate a faster rate of GE of oats when feeding oats before hay and there was approximately 1 h difference in T max . Oats will spend less time in the stomach when feeding oats before hay, but how this affects the digestion of starch in the stomach, small intestine and hindgut needs further investigations. In conclusion, the 13 C-ABT is a promising minimal invasive technique for measuring GE in horses.

An unusual cause of intraoperative hypercarbia: Who's the boss:- Machine or The Man behind the machine?

Sir, Modern integrated anaesthesia workstations provide comprehensive facilities for patient ventilation, gas delivery and agent vapourisation, and allow seamless integration of patient monitoring and recording with anaesthesia information systems. American Society of Anesthesiologists (ASA) 2008 recommendations for pre-anaesthesia checkout advocate pre-use testing of anaesthesia machine before the conduct of anaesthesia.[1] Modern anaesthesia workstations including Dräger Perseus® A500 (Dräger, Germany) have integrated automatic self-testing to circumvent human errors and ensure administration of safe anaesthesia.[2] A 5 year-old boy with left hydrocele was posted for elective open herniotomy. Dräger Perseus® A500 anaesthesia workstation (Dräger, Germany) which had already passed an automated self-test was used to administer general anaesthesia with controlled ventilation using i-gel® supraglottic airway device (Intersurgical Limited, Wokingham) in-situ with ultrasound-guided left ilioinguinal and iliohypogastric nerve block. After obtaining valid informed parental consent, the child was pre-medicated with oral midazolam 0.5 mg/kg and wheeled into the operating room (OR). Standard ASA monitors were attached and incremental induction with sevoflurane (2-8%) was done. On achieving jaw relaxation and loss of purposeful movement, size 2 i-gel® was inserted and controlled ventilation using volume control auto-flow mode initiated. Anaesthesia was maintained using air-oxygen (50:50) and sevoflurane titrated to maintain age-adjusted minimum alveolar concentration (MAC) -1, with fresh gas flows (FGF) of 0.5 L/min. Following this, ultrasound-guided left-sided ilioinguinal and iliohypogastric nerve block using 0.15 ml/kg of 0.25% bupivacaine was given. A few minutes later, end-tidal carbon dioxide (ETCO2) and fraction of inspired carbon dioxide (FiCO2) values were observed to have risen from baseline values of 34 to 62 and 0 to 16 respectively. Switching over to the manual controlled mode of ventilation showed no increase in airway resistance (peak airway pressure <15 cm H2O) with bilaterally equal breath sounds. However, ETCO2 values continued to rise. At this point, we switched over to Jackson Rees (JR) circuit, to rule out the possibility of a faulty closed circuit. Simultaneously, a quick survey of the machine revealed an empty absorbent canister. The same was immediately refilled, following which ETCO2 values gradually normalised. Increased ETCO2 under anaesthesia is either due to decreased excretion or increased production [Table 1].[34] In accordance with our OR standard operating procedure (SOP), the canisters are refilled as required, which is usually on completion of the last case of the day. Visual inspection for exhausted carbon dioxide absorbent is a standard practice in the ASA checklist. We failed to identify the empty canister on visual inspection prior to beginning the case, which was a gross error irrespective of the high-end anaesthesia workstation. However, the machine passed the automated self-test and did not alert us regarding the same. Dräger Perseus® A500 workstation (Dräger, Germany) has two functional tools to support the safe conduct of low flow anaesthesia viz. the Low Flow Wizard and the Econometer.[5] Low Flow Wizard enables real-time analysis of data like patient uptake, breathing system leakage and the volume of carbon dioxide absorbed by the absorbent and compares the sum of these values with the actual FGF.[5] Econometer displays the FGF in a colour-coded bar graph based on filling of the manual breathing bag with each delivered breath, thus enabling a judicious and economical FGF set-up.[5] However, none of these tools are designed to identify the presence of an empty absorbent canister per se or indicate the time to complete exhaustion.Table 1: Causes of increased end-tidal carbon dioxide[4]We recommend that automated self-tests should include testing for presence of the absorbent to ensure patient safety. This assumes greater importance particularly in the context of increasing practice of paediatric low flow anaesthesia. Furthermore, an in-built alarm indicating the absorbent's functional capacity should be incorporated into the anaesthesia workstation to avert human errors and avoid hypercarbia. The advancements of the century may be leading us to an era of robotic anaesthesia and hi-tech workstations; nonetheless, “it is not the machine, but the man behind it that matters.” Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Q‐VENT—A novel device for emergency ventilation of the lungs in patients with respiratory failure due to diseases such as COVID‐19

AbstractSince the end of 2019, a novel coronavirus (SARS‐CoV‐2) causing pneumonia, often progressing to rapid deterioration with acute respiratory distress syndrome (ARDS) requiring advanced life support, has been spreading worldwide. The humanitarian crisis we are currently witnessing across the globe is threatening access to artificial ventilation of the lungs (AVL) for patients with respiratory failure. Q‐vent is a multi‐way air valve system with filters and heater/humidifier module produced by 3D printer from a new composite material based on Phloxine B, Saponite and Polylactic acid that prevents the formation of bacterial biofilms. This automated device, which can be fitted with commercially available Ambu® Breathing Bags or similar, provides a high degree of controllability along with one‐box complexity. A built‐in cough sensor warns of patient's awakening. In the case of power failure, Q‐vent switches to battery reserve. The developed device was tested on an intubated model (Gaumard® Scientific ‐ UNI®) corresponding to a patient (80 kg) with lung compliance 50 ml/cm H2O to simulate ARDS for 24 hours. The inspiration‐to‐expiration (I:E) ratio, tidal volume set to 8 ml/kg PBW (L‐type pneumonia) and 6 ml/kg PBW (H‐type Pneumonia), and frequency of inspiration were adjusted to test Q‐Vent operation at a range of different conditions. All functions performed reliably throughout the testing procedure. Q‐Vent successfully passed the Rapidly Manufactured Ventilator System (RMVS001) validation issued by MHRA and is awaiting clinical trials to determine its value in overcoming crises caused by the lack of conventional AVL.

Effect of new simple breathing apparatus on oxygen therapy in patients with severe and critical coronavirus disease 2019

To make a new simple respirator and observe the oxygen therapy effect of the respirator on patients with severe and critical coronavirus disease 2019 (COVID-19). Based on the infectivity and hospital requirements of COVID-19, a new simple respirator was designed by the medical staff of the Department of Anesthesiology of the Second Affiliated Hospital of Nanchang University, which was applied on the 22 patients with severe and critical COVID-19 who needed oxygen therapy admitted to the Cancer Center of Tongji Medical College of Huazhong University of Science and Technology from February 15th to March 15th in 2020. The new simple respirator contained two National Utility Model Patents (a respirator: ZL 2015 2 0410623.6, a fluid switch and oxygen suction device: ZL 2017 2 0873509.6), which was mainly composed of anesthesia mask and filter, L-shaped connecting tube, soft breathing bladder, connecting tube and elastic fixing belt. When in use, the anesthesia mask was fixed to the patient's mouth and nose with elastic straps, the connecting tube was inserted into the oxygen meter interface, the oxygen flow was adjusted to 6-10 L/min, and the L-shaped connecting tube was opened immediately after the soft breathing bag was full. The carbon dioxide and excess oxygen in the body was discharged from exhaust port. The oxygen flow was lowered to 2-3 L/min, the patient's respiratory rate (RR) was observed through the soft breathing bag fluctuations, and the oxygen flow was adjusted at any time. The changes of pulse oxygen saturation (SpO2), RR and heart rate (HR) before and after application of new simple respirator were observed, and the blood gas test results of part of the patients were collected. Twenty-two patients with severe and critical COVID-19 had significantly higher SpO2 at 10 minutes after application of the new simple ventilator than before application (0.994±0.007 vs. 0.952±0.017, P < 0.01), and RR was significantly lower than that before application (times/min: 27.59±3.63 vs. 29.64±3.81, P < 0.01); after 1 day of application, each index was further improved. All 13 patients who received blood gas analysis indicated no carbon dioxide accumulation. The new simple respirator can significantly improve the oxygen therapy effect of patients with severe and critical COVID-19. At the same time, 2019 novel coronavirus (2019-nCoV) can be filtered through the filter to reduce the formation of aerosol and protect the medical staff and patients.

Characterization of standardized breath sampling for off-line field use

Due to several sources of potential variability associated with exhaled breath bag sampling procedures for off-line analysis, the Respiration Collector for in vitro Analysis (ReCIVA) sampler was developed. Although designed to improve upon several pitfalls of sampling with exhaled breath bags, the ReCIVA remains a minimally studied research tool. In this manuscript, several attributes of the ReCIVA sampler are investigated among three individual tests, such as background contamination, control software version, performance of different adsorbent tubes, duplicate sample production, and comparison to exhaled breath bags. The data shows greater than a 58% reduction in background siloxanes can be achieved with submersion of ReCIVA masks in ethyl alcohol or baking the masks at a high temperature (200 °C). The results illustrate the ReCIVA control software version plays a key role in the flow rates applied to thermal desorption (TD) tubes. Using exhaled isoprene as a representative analyte, the data suggest duplicate samples among ReCIVA pump banks can be achieved using two different thermal desorption tubes, Tenax TA and Tenax/Carbograph 5TD, when using an updated control software and manually calibrating the ReCIVA pumps to uniform flow rates (Tenax p = 0.3869, 5TD p = 0.3131). Additionally, using the updated control software and manual ReCIVA flow calibration, the data suggest the ReCIVA can produce statistically similar results among TD tube types (p = 0.3824) and compared to standard exhaled breath bags (p = 0.1534). Collectively, these results establish a method for manually calibrating the flow of the ReCIVA device to allow for the most consistent results. These data support further experimentation into the use of the ReCIVA sampler for exhaled breath research.

Evaluation on the Wear Fit and Activity of Emergency Escape Breathing Devices for Ship Accidents

선박 운항 중 화재나 사고 시에 선박 내부의 복잡한 구조나 침수로 인해 갑판으로의 신속한 피난이 어려울 경우 유해가스나 산소 부족에 대응하기 위해서는 비상탈출용 호흡구난장비가 필수적이다. 최근 국내에서도 비상탈출호흡 구가 개발 보급되고 있으나, 기본 성능만 만족할 뿐 실제 사용시의 착용성 및 활동성에 대한 평가 사례가 없어 그효용성에 대해 의혹이 크다. 본 연구에서는 선박사고에 적합한 비상탈출호흡구에 대한 착용성 및 활동성 평가 항목을 제반 국제 기준으로부터 도출하였고, 개방식과 폐쇄식 각각의 국산 제품 샘플에 대한 평가를 수행하였다. 개방식은 시인성, 착용시간, 호흡저항 및 호스 걸림 부분에서, 폐쇄식은 정화통 방해, 무게 불균형, 호흡백 시야 가림 부분에서 개선이 필요한 것으로 평가되었다. ABSTRThe use of emergency escape breathing devices (EEBD) is strongly required to protect against toxic gas or flooding caused by ship fires or accidents. Recently developed domestic EEBD products only satisfy the basic performance requirements, but no wear fit and activity performance evaluation has been done for real usage. In this study, the global level test requirements for wear comfort and activity of EEBDs were developed and the open and closed type of domestic EEBD products were evaluated. Poor visibility, longer wear time, breathing resistance, and hose obstruction in an open type and canister obstruction, weight unbalance, and an invisible black breathing bag in the closed type EEBD were estimated to be the main problems that need to be improved.

Assessment of a Noninvasive Exhaled Breath Test for the Diagnosis of Oesophagogastric Cancer

Early esophagogastric cancer (OGC) stage presents with nonspecific symptoms. The aim of this study was to determine the accuracy of a breath test for the diagnosis of OGC in a multicenter validation study. Patient recruitment for this diagnostic validation study was conducted at 3 London hospital sites, with breath samples returned to a central laboratory for selected ion flow tube mass spectrometry (SIFT-MS) analysis. Based on a 1:1 cancer:control ratio, and maintaining a sensitivity and specificity of 80%, the sample size required was 325 patients. All patients with cancer were on a curative treatment pathway, and patients were recruited consecutively. Among the 335 patients included; 172 were in the control group and 163 had OGC. Breath samples were collected using secure 500-mL steel breath bags and analyzed by SIFT-MS. Quality assurance measures included sampling room air, training all researchers in breath sampling, regular instrument calibration, and unambiguous volatile organic compounds (VOCs) identification by gas chromatography mass spectrometry. The risk of cancer was identified based on a previously generated 5-VOCs model and compared with histopathology-proven diagnosis. Patients in the OGC group were older (median [IQR] age 68 [60-75] vs 55 [41-69] years) and had a greater proportion of men (134 [82.2%]) vs women (81 [47.4%]) compared with the control group. Of the 163 patients with OGC, 123 (69%) had tumor stage T3/4, and 106 (65%) had nodal metastasis on clinical staging. The predictive probabilities generated by this 5-VOCs diagnostic model were used to generate a receiver operator characteristic curve, with good diagnostic accuracy, area under the curve of 0.85. This translated to a sensitivity of 80% and specificity of 81% for the diagnosis of OGC. This study shows the potential of breath analysis in noninvasive diagnosis of OGC in the clinical setting. The next step is to establish the diagnostic accuracy of the test among the intended population in primary care where the test will be applied.

Portable Device for Measuring Breath Acetone Based on Sample Preconcentration and Cavity Enhanced Spectroscopy.

A portable and compact device is demonstrated for measuring acetone in breath samples. The device features a 7 cm long high finesse optical cavity as an optical sensor that is coupled to a miniature adsorption preconcentrator containing 0.5 g of polymer material. Acetone is trapped out of breath and released into the optical cavity where it is probed by a near-infrared diode laser operating at ∼1670 nm. With an optical cavity mirror reflectivity of 99.994%, a limit of detection of 159 ppbv (1σ) is demonstrated on samples from breath bags. Initial results on direct breath sampling are presented with a precision of 100 ppbv. The method is validated with measurements made using an ion-molecule reaction mass spectrometer. Data are presented on elevated breath acetone from two individuals following an overnight fast and exercise, and from a third individual during several days of routine behavior.

Respiratory Monitoring System for Underwater Use

Monitoring a diver's respiratory parameters is a challenge. A respiratory monitoring system (RMS) should allow measurements of gas flows, gas composition (O2 and CO2, breath by breath) and pressure swings at the mouth. For physiologic research, breathing resistance and gas composition should be independently adjustable. The pressure of the breathing gas relative to the diver's lung centroid (static lung loading, hydrostatic imbalance) should be controlled. Ideally, an RMS has no depth limitations.In the RMS described here, the diver breathes through a full face mask and large bore hoses to an inspiratory and an expiratory side. Each side has a flow meter and temperature and pressure (relative to the mask) sensors. The inspiratory side is supplied with a constant, surface‐adjustable gas flow to a bag from which the diver breathes. This flow is adjusted to keep the bag full at the beginning of inhalation. Excess gas bubbles into the water. Expiration is buffered by another bag and bubbles into the water.Gas from the mask is sampled to a mass spectrometer for continuous analysis. The flow meter, mass spectrometer, pressure and temperature signals are displayed in real time and recorded.The prone diver is positioned on a cycle ergometer that keeps the chest in a known position relative to the RMS. The depth of the exhaust ports of the RMS relative to the diver's lung centroid controls hydrostatic imbalance. Resistance elements can be added to either breathing hose. The size and shape of the breathing bags set elastic loads.Breathing gas with selected concentrations of O2 and CO2 permits assessment of gas composition effects on respiratory performance when a diver is challenged by experimenter‐imposed respiratory impediments. The RMS has been used in a pool at a depth of about 3 m in close to 100 experiments without incident.

Erroneous tidal volume measurement due to malfunctioned spirolog flow sensor

Received: June 10, 2015; Accepted: July 27, 2015; Published: August 10, 2015 An 60 year-old obese class I woman (weight 80 kg, height 160 cm, body mass index 31.25) was mechanically ventilated for an abdominal surgery, using Fabius GS anesthesia machine (Draeger Medical, AG &Co, Lubeck, Germany). Before usage, the anesthesia machine had undergone a standard morning operational check up in which all apparatus components passed. A set tidal volume (TV) of 600 ml was installed. Although the expected TV administered to the patient was supposed to be within the range of the predetermined values (600 ml), the actual TV that had been measured by the Spirolog flow sensor fluctuated between 270 to 290 ml only. Physical examination including inspection of gross chest movement and lung auscultation revealed a fairly ventilated patient. End tidal CO2 was around 35 mmHg, peak inspiratory pressure 23-35mmHg and the state of muscle relaxation adequate. Raising the fresh gas flow to 6 liters per minute, switching to manual ventilation mode and compressing the inflated breathing bag with semi-closed adjustable pressure limiting valve to check for leaks did not unveil the reason for a leak neither within the anesthesia machine nor in the breathing circuit and airways surroundings. To rule out an unnoticed miniature puncture in the disposable circle tubing, it was replaced by a new kit and a second leak test was made, which again passed without revealing the source to any faulty element.

Comparison of breath gases, including acetone, with blood glucose and blood ketones in children and adolescents with type 1 diabetes

Previous studies have suggested that breath gases may be related to simultaneous blood glucose and blood ketone levels in adults with type 2 and type 1 diabetes. The aims of this study were to investigate these relationships in children and young people with type 1 diabetes in order to assess the efficacy of a simple breath test as a non-invasive means of diabetes management. Gases were collected in breath bags and measurements were compared with capillary blood glucose and ketone levels taken at the same time on a single visit to a routine hospital clinic in 113 subjects (59 male, age 7 years 11 months–18 years 3 months) with type 1 diabetes. The patients were well-controlled with relatively low concentrations of the blood ketone measured (β hydroxybutyrate, 0–0.4 mmol l−1). Breath acetone levels were found to increase with blood β hydroxybutyrate levels and a significant relationship was found between the two (Spearman’s rank correlation ρ = 0.364, p < 10−4). A weak positive relationship was found between blood glucose and breath acetone (ρ = 0.16, p = 0.1), but led to the conclusion that single breath measurements of acetone do not provide a good measure of blood glucose levels in this cohort. This result suggests a potential to develop breath gas analysis to provide an alternative to blood testing for ketone measurement, for example to assist with the management of type 1 diabetes.

Micropreconcentrator in LTCC Technology with Mass Spectrometry for the Detection of Acetone in Healthy and Type-1 Diabetes Mellitus Patient Breath.

Breath analysis has long been recognized as a potentially attractive method for the diagnosis of several diseases. The main advantage over other diagnostic methods such as blood or urine analysis is that breath analysis is fully non-invasive, comfortable for patients and breath samples can be easily obtained. One possible future application of breath analysis may be the diagnosing and monitoring of diabetes. It is, therefore, essential, to firstly determine a relationship between exhaled biomarker concentration and glucose in blood as well as to compare the results with the results obtained from non-diabetic subjects. Concentrations of molecules which are biomarkers of diseases’ states, or early indicators of disease should be well documented, i.e., the variations of abnormal concentrations of breath biomarkers with age, gender and ethnic issues need to be verified. Furthermore, based on performed measurements it is rather obvious that analysis of exhaled acetone as a single biomarker of diabetes is unrealistic. In this paper, the author presents results of his research conducted on samples of breath gas from eleven healthy volunteers (HV) and fourteen type-1 diabetic patients (T1DM) which were collected in 1-l SKC breath bags. The exhaled acetone concentration was measured using mass spectrometry (HPR-20 QIC, Hiden Analytical, Warrington, UK) coupled with a micropreconcentrator in LTCC (Low Temperature Cofired Ceramic). However, as according to recent studies the level of acetone varies to a significant extent for each blood glucose concentration of single individuals, a direct and absolute relationship between blood glucose and acetone has not been proved. Nevertheless, basing on the research results acetone in diabetic breath was found to be higher than 1.11 ppmv, while its average concentration in normal breath was lower than 0.83 ppmv.

Investigation and analysis on disaster site first aid skills of community healthcare workers

Objective The aim of this study was to investigate the status on disaster site first aid skills of community healthcare workers at Hangzhou and to provide medical institution with a reference to train the disaster site first aid skills .Methods The researchers investigated 400 healthcare workers ’ disaster site first aid skills from 8 community health service centers .Results Totals of 373 questionnaires were returned with an effective rate of 93.5%.The average score of disaster site first aid skills of community healthcare workers was （3.83 ±0.28）.The score of using simple breathing bag was （4.33 ±0.70）.The score of performing CPR technique was （4.21 ±0.70）.Logistic regression analysis showed that the influencing factors of disaster site first aid skills were participation in disaster rescue and the male gender （P〈0.05）.100% of the community healthcare workers were interested in learning disaster site first aid skills .93.7% of the community healthcare workers expressed a strong willingness to learn relevant skills .Conclusions The overall level of the disaster site first aid skills of community healthcare workers is not good , but their learning intention are strong .It is necessary to strengthen the disaster site first aid skills training and to take various training programs which cover a wide range of contents , such as disaster rescue simulation exercises , scenario simulation test and participation in the site rescue.Meanwhile, continuing education opportunities should be actively provided to enhance the disaster site first aid skills of community healthcare workers . Key words: Community health care service; Disaster; Data collection; Healthcare professional; On-site first aid skills