Expiratory Research Articles

COPD stage detection: leveraging the auto-metric graph neural network with inspiratory and expiratory chest CT images.

Chronic obstructive pulmonary disease (COPD) is a common lung disease that can lead to restricted airflow and respiratory problems, causing a significant health, economic, and social burden. Detecting the COPD stage can provide a timely warning for prompt intervention in COPD patients. However, existing methods based on inspiratory (IN) and expiratory (EX) chest CT images are not sufficiently accurate and efficient in COPD stage detection. The lung region images are autonomously segmented from IN and EX chest CT images to extract the lung radiomics and 3D CNN features. Furthermore, a strategy for concatenating and selecting features was employed in COPD stage detection based on radiomics and 3D CNN features. Finally, we combine all the radiomics, 3D CNN features, and factor risks (age, gender, and smoking history) to detect the COPD stage based on the Auto-Metric Graph Neural Network (AMGNN). The AMGNN with radiomics and 3D CNN features achieves the best performance at 89.7 of accuracy, 90.9 of precision, 89.5 of F1-score, and 95.8 of AUC compared to six classic machine learning (ML) classifiers. Our proposed approach demonstrates high accuracy in detecting the stage of COPD using both IN and EX chest CT images. This method can potentially establish an efficient diagnostic tool for patients with COPD. Additionally, we have identified radiomics and 3D CNN as more appropriate biomarkers than Parametric Response Mapping (PRM). Moreover, our findings indicate that expiration yields better results than inspiration in detecting the stage of COPD.

Exhalomics as a noninvasive method for assessing rumen fermentation in dairy cows: Can exhaled-breath metabolomics replace rumen sampling?

Previously, we used secondary electrospray ionization-mass spectrometry (SESI-MS) to investigate the diurnal patterns and signal intensities of exhaled (EX) volatile fatty acids (VFA) of dairy cows. The current study aimed to validate the potential of an exhalomics approach for evaluating rumen fermentation. The experiment was conducted in a switchback design, with 3 periods of 9 d each, including 7 d for adaptation and 2 d for sampling. Four rumen-cannulated original Swiss Brown (Braunvieh) cows were randomly assigned to 1 of 2 diet sequences (ABA or BAB): (A) low starch (LS; 6.31% starch on a dry matter basis) and (B) high starch (HS; 16.2% starch on a dry matter basis). Feeding was once per day at 0830 h. Exhalome (with the GreenFeed System), and rumen samples were collected 8 times to represent every 3 h of a day, and EX-VFA and ruminal (RM)-VFA were analyzed using SESI-MS and HPLC, respectively. Furthermore, the VFA concentration in the gas phase (HR-VFA) was predicted based on RM-VFA and Henry's Law (HR) constants. No interactions were identified between the types of diets (HS vs. LS) and the measurement methods on daily average VFA profiles (RM vs. EX or HR vs. EX), suggesting a consistent performance among the methods. Additionally, when the 3-h interval VFA data from HS and LS diets were analyzed separately, no interactions were observed between methods and time of day, indicating that the relative daily pattern of VFA molar proportions was similar regardless of the VFA measurement method used. The results revealed that the levels of acetate sharply increased immediately after feeding, trailed by an increase in the acetate:propionate ratio and a steady increase for propionate (2 h after feeding the HS diet, 4 h for LS), and butyrate. This change was more pronounced for the HS diet than the LS diet. However, there was no overall diet effect on the VFA molar proportions, although the measurement methods affected the molar proportions. Furthermore, we observed a strong positive correlation between the levels of RM and EX acetate for both diets (HS: r = 0.84; LS: r = 0.85), RM and EX propionate (r = 0.74), and RM and EX acetate:propionate ratio (r = 0.80). Both EX-VFA and RM-VFA exhibited similar responses to feeding and dietary treatments, suggesting that EX-VFA could serve as a useful proxy for characterizing RM-VFA molar proportions to evaluate rumen fermentation. Similar relationships were observed between RM-VFA and HR-VFA. In conclusion, this study underscores the potential of exhalomics as a reliable approach for assessing rumen fermentation. Moving forward, research should further explore the depth of exhalomics in ruminant studies to provide a comprehensive insight into rumen fermentation metabolites, especially across diverse dietary conditions.

P039 Genioglossus motor control during mandibular advancement.

Abstract Introduction High genioglossus muscle activity is thought to prevent/resolve upper airway collapse. Overall genioglossal activity results from the simultaneous firing of many motor units (MUs) which typically have one of 5 firing patterns: active only (IP) or at higher frequency (IT) during inspiration; active only (EP) or at higher frequency during expiration (ET); and constantly active without respiratory modulation (TT). To date, most experimental manipulations tested (e.g. hypoxia, hypercapnia, resistive loading) have influenced IP and IT MUs, with minimal changes in ET, EP and TT MUs. We hypothesized that IT/IP MUs respond to respiratory drive, whereas TT/EP/ET MUs will change in response to airway anatomical manipulations. Methods The number and firing frequencies of genioglossal MUs were assessed with intramuscular electrodes in healthy individuals during wakefulness, before and during mandibular advancement (MAD) to 80% of maximum with an myTAP device, to change airway anatomy but minimally alter respiratory drive. Results 201 MUs were identified from 55 trials in 14 participants. Ventilation did not differ between baseline and MAD. At baseline, 175 MUs were active: EP=0.6%, ET=12.6%, IP=14.9%, IT=48%, TT=24%. During MAD, 35 MUs ceased firing, but an additional 26 MUs began firing, with the resulting MUs proportions not differing from baseline: EP=0%, ET=10.2%, IP=21.1%, IT=36.7%, TT=31.9%, χ2(9)=12.0, p=.213. The mean firing frequency of MUs did not change during MAD (baseline=20.9±4.7Hz, MAD=21.9±5.4Hz). Discussion Contrary to the hypothesis, the firing patterns of genioglossal MUs did not differ from baseline during mandibular advancement. What controls the non-respiratory/expiratory MUs of the genioglossus remains unclear.

A technique to determine the end-expiratory lung volume and dead space in a ventilated patient: Theoretical considerations

The term “dead space (VD)” refers to the volume of air/gas in the respiratory tract which does not take part in gas exchange. VD can increase in some pathological settings and has been found to be a prognostic marker in acute lung injury and respiratory distress syndrome. The end-expiratory lung volume (EELV) in a mechanically ventilated patient is the volume in the lungs at the end of passive expiration which is often influenced by disease, atelectasis, airway resistance, shunt, pulmonary vascular resistance, right heart strain, etc. Measuring EELV and VD may allow monitoring of disease state and treatment effect. VD can be derived from the arterial and exhaled CO2 partial pressures. In the intensive care unit, certain ventilators can measure EELV automatically. Unfortunately, there are no means of measuring EELV in the operating room. We herein propose a technique that may theoretically allow for measurement of the EELV and VD in the operating room setting without special equipment or an arterial blood sample.

High frequency jet-ventilation anaesthesia in patients with laryngeal patholog

Airway management in laryngeal surgeries is a challenge for an anesthesiologist due to sharing of airway with a surgeon. The airway is often compromised with potential for perioperative worsening. Introduction of high-frequency jet ventilation (HFJV) in 1970 offered a new modality to secure airway in the laryngology procedures, excluding the disadvantages of classic tracheal intubation. HFJV is characterized by delivery of small tidal volumes (1–2 ml/kg) from a high-pressure jet at supraphysiological frequencies (1–10 Hz) followed by passive expiration. At ENT clinic of “T.Moșneaga” hospital HFJV are used for several years. Applied via supraglottic aproach, HFJV is first choice in patients with severe laryngeal obstruction, lesions of posterior glottic regions, a lot of pacients being suffering of laryngeal papillomatosis. This method can be safely used in microlaryngeal surgery, excluding a lot of serious intraoperative complications, esspecially combustions of conventional endotracheal tubes. Till now, there are not reported complications in our local practice of HFJV.

Model-based Estimation of Neonatal Pleural Pressure

Spontaneous breathing during mechanical ventilation is common in the neonatal intensive care unit. The breathing efforts in spontaneous breaths generate negative pressures in the pleural space, complicating model-based analysis due to unknown parameter tradeoff. This paper estimates the pleural pressure and elastance in a single compartment model applied to data from a neonate undergoing synchronous intermittent mandatory ventilation. Two sets of 60 breaths were analysed. Resistance is empirically modelled based on endotracheal tube dimensions. Breath-to-breath elastance is estimated from expiration data, assuming passive expiration, and inspiratory pleural pressure is modelled using B-spline functions. Typical breathing trends were observed, patient-triggered inspiration was apparent, and the work of breathing was significantly decreased in ventilator supported breaths compared to unsupported breaths. Additionally, examples of ventilator-patient asynchrony were observed when comparing pleural pressure to airway pressure. This study contributes to the development of computational models for respiration mechanics. The fundamental aim is to provide clinicians with more physiological insight and tools to improve neonatal ventilation support.

Study of Nocturnal Oxygen Desaturation in Chronic Obstructive Pulmonary Disease Patients

Background: Abnormal sleep architecture with decreased rapid eye movement sleep and arousals during the periods of nocturnal oxygen desaturation (NOD) are seen in patients with chronic obstructive pulmonary disease (COPD) with significant consequences. This study was done to evaluate the prevalence of NOD and other sleep-related disorders in COPD patients. Patients and Methods: This prospective cross-sectional study was conducted in the sleep laboratory of our tertiary center over 1 year. Fifty COPD patients were enrolled in this study. They were classified into mild COPD and moderate COPD, according to the Global Initiative for Obstructive Lung Disease (GOLD) classification. Complete history, physical examination, and relevant laboratory investigations were taken. All patients were subjected to overnight polysomnography. Results: Eight patients had mild COPD, whereas 42 patients had moderate COPD. Mean sleep efficiency was decreased with an average of 71.08% with a significant difference between mild and moderate COPD cases. Minimal SpO2, average SpO2, SpO2

Acute Exacerbation of Chronic Obstructive Pulmonary Disease in Rural Area: Why, How, and What Next?

Background: Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) leads to fall in lung function, quality of life, and ultimately disease progression. The present study is an effort to study in detail about COPD exacerbation in a rural tertiary hospital. Aim: To study demographic, clinical, and laboratory profile of hospitalized patients of AECOPD. Methodology: Retrospective data of 170 consecutive patients of AECOPD were collected from records, were divided into two groups based on severity, and were analyzed: Group 1 for admission in the wards and Group 2 for intensive care unit (ICU) admissions. Results: A total of 141 (82.9%) patients were hospitalized in the wards, whereas 29 (17.1%) were admitted in the ICU. The mean age was 62.36 years in the wards and 64.89 years in the ICU. Nearly 89.4% of patients were smokers. Dyspnea (100%) was the most common symptom followed by cough (99%) and expectoration (98%). The mean respiratory rate at the time of presentation was 26/min in the wards and 31.56/min in the ICU. The mean oxygen saturation was 93% in the wards and 88.62% in the ICU. The mean post forced expiratory volume in 1 s (FEV1) was 43.98% in ward patients and 29.28% among ICU patients. Arterial blood gas revealed mean PaCO2 of 44.25 mmHg in the wards and 63.24 mmHg in the ICU. The mean pH in the ward was 7.48 compared to 7.34 in the ICU. The mean pulmonary arterial pressure (PAP) was higher in the ICU (53.74 mmHg) than in the ward (38.87 mmHg). Conclusion: The ratio of hospitalization in ICU to ward was 1:5. The site of treatment depends on respiratory rate, oxygen saturation, post-FEV1%, PAP, pH, and PaCO2.

Projected frontal area and its components during front crawl depend on lung volume.

We examined the influence of lung volume on the vertical body position, trunk inclination, and projected frontal area (PFA) during swimming and the inter-relationships among these factors. Twelve highly trained male swimmers performed a 15 m front crawl with sustained maximal inspiration (INSP), maximal expiration (EXP), and intermediate (MID) at a target velocity of 1.20 m·s-1 . Using our developed digital human model, which allows inverse kinematics calculations by fitting individual body shapes measured with a three-dimensional photonic image scanner to individually measured underwater motion capture data, vertical center of mass (CoM) position, trunk inclination, and PFA were calculated for each complete stroke cycle. In particular, the PFA was calculated by automatic processing of a series of parallel frontal images obtained from a reconstructed digital human model. The vertical CoM position was higher with a larger lung-volume level (p < 0.01). The trunk inclination was smaller in INSP and MID than in EXP (p < 0.01). PFA was smaller with a larger lung-volume level (p < 0.01). Additionally, there was a significant interaction of vertical CoM position and trunk inclination with PFA (p=0.006). There was a negative association between PFA and vertical CoM position, and a positive association between PFA and trunk inclination less than the moderate vertical CoM position (each p < 0.05). These results obtained using our methodology indicate that PFA decreases with increasing lung volume due to an increase in vertical CoM position, and additionally due to a decrease in trunk inclination at low-to-moderate lung-volume levels.

Quantitative CT lung densitometry as an obstructive marker for the diagnosis of bronchiolitis obliterans in children.

The purpose of this study is to evaluate the quantitative diagnostic performance of computed tomography (CT) densitometry in pediatric patients with bronchiolitis obliterans (BO). We measured the mean lung density (MLD) and represented the difference of MLD in inspiratory and expiratory phases (MLDD), the ratio of the MLD (E/I MLD), and the relative volume percentage of lung density at 50-Hounsfield unit (HU) interval threshold (E600 to E950). We calculated the sensitivity, specificity, and diagnostic accuracy of the lung density indices for the diagnosis of BO. A total of 81 patients, including 51 patients with BO and 30 controls, were included in this study. In the BO patients, expiratory (EXP) MLD and MLDD were significantly lower, and E/I MLD and expiratory low attenuation areas below the threshold of −850 HU to −950 HU (E850, E900, and E950) were statistically significantly higher than controls. Multivariate logistic regression analysis showed that MLDD (odds ratio [OR] = 0.98, p < .001), E/I MLD (OR = 1.39, p < .001), and E850 to E950 were significant densitometry parameters for BO diagnosis. In a receiver-operating characteristic analysis, E900 (cutoff, 1.4%; AUC = 0.920), E/I MLD (cutoff, 0.87; AUC = 0.887), and MLDD (cutoff, 109 HU; AUC = 0.867) showed high accuracy for the diagnosis of BO. In conclusion, the lung CT densitometry can serve as a quantitative marker providing additional indications of expiratory airflow limitation in pediatric patients with BO.

Flow-controlled expiration (FLEX) homogenizes pressure distribution in a four compartment physical model of the respiratory system with chest wall compliance

Objective. Flow-controlled expiration (FLEX) has been shown to attenuate ventilator-induced lung injury in animal models. It has also shown to homogenize compartmental pressure distribution in a physical model of the inhomogeneous respiratory system having independent compartments. We hypothesized that the homogenizing effects of FLEX are also effective in this regard when the independence of compartments is suspended by simulated chest wall compliance. Approach. A four compartment physical model of the respiratory system having chest wall compliance (137 ml/cmH2O) was developed. Two of the four compartments had high compliance (18 ml/cmH2O) and two had low compliance (10 ml/cmH2O). These compartments were each combined with either high (6.8 cmH2O·s/l) or low resistance (3.5 cmH2O·s/l). The model was ventilated in the volume-controlled ventilation mode with either passive expiration or with FLEX. The maximal pressure differences (ΔP max) and the maximal differences of mean pressure (ΔP mean) between the compartments during expiration were determined. Main results. With passive expiration ΔP max reached up to 3.4 ± 0.03 cmH2O but only 0.9 ± 0.01 cmH2O with FLEX (p < 0.001). Maximal differences of ΔP mean were significantly lower with FLEX as compared to passive expiration (extending up to 0.4 ± 0.04 cmH2O versus 2.0 ± 0.15 cmH2O, p < 0.001). Significance. The homogenizing effects of FLEX on compartmental pressure distribution could be reproduced in a more complex physical model of the inhomogeneous respiratory system having chest wall compliance and might be a mechanism underlying the lung protective effects of ventilation with FLEX.

Tiny golden angle stack-of-stars (tygaSoS) free-breathing functional lung imaging

PurposeMRI of the lung parenchyma is still challenging due to cardiac and respiratory motion, and the low proton density and short T2*. Clinical feasible MRI methods for functional lung assessment are of great interest. It was the objective of this study to evaluate the potential of combining the ultra-short echo-time stack-of-stars approach with tiny golden angle (tyGASoS) profile ordering for self-gated free-breathing lung imaging. MethodsFree-breathing tyGASoS data were acquired in 10 healthy volunteers (3 smoker (S), 7 non-smoker (NS)). Images in different respiratory phases were reconstructed applying an image-based self-gating technique. Resulting image quality and sharpness, and parenchyma visibility were qualitatively scored by three blinded independent reader, and the signal-to-noise ratio (SNR), proton fraction (fP) and fractional ventilation (FV) quantified. ResultThe imaging protocol was well tolerated by all volunteers. Image quality was sufficient for subsequent quantitative analysis in all cases with good to excellent inter-reader reliability. Between expiration (EX) and inspiration (IN) significant differences (p < 0.001) were observed in SNR (EX: 3.73 ± 0.89, IN: 3.14 ± 0.74) and fP (EX: 0.27 ± 0.09, IN: 0.25 ± 0.08). A significant (p < 0.05) higher fP (EX/IN: 0.22 ± 0.07/0.21 ± 0.07 (NS), 0.33 ± 0.07/0.30 ± 0.06 (S)) was observed in the smoker group. No significant FV differences resulted between S and NS. ConclusionThe study proves the feasibility of free-breathing tyGASoS for multiphase lung imaging. Changes in fP may indicate an initial response in the smoker group and as such proves the sensitivity of the proposed technique. A major limitation in FV quantification rises from the large inter-subject variability of breathing patterns and amplitudes, requiring further consideration.

Ambulatory chest physiotherapy in mild-to-moderate acute bronchiolitis in children under two years of age- A randomized control trial.

Objective:The aim of this study was to compare the role of a chest physiotherapy (CP) intervention to no intervention on the respiratory status of children under two years of age, with mild-to-moderate bronchiolitis.Methods:Out of 80 eligible children observed in the Emergency Room, 45 children completed the study with 28 randomized to the intervention group and 17 to the control group. The intervention protocol, applied in an ambulatory setting, consisted of combined techniques of passive prolonged slow expiration, rhinopharyngeal clearance and provoked cough. The control group was assessed with no chest physiotherapy intervention. The efficacy of chest physiotherapy was assessed using the Kristjansson Respiratory Score at the admission and discharge of the visit to the Emergency Room and during clinical visits at day 7 and day 15.Results:There was a significant improvement in the Kristjansson Respiratory Score in the intervention group compared to the control group at day 15 [1.2 (1.5) versus 0.3 (0.5); -value, in the control and intervention groups, respectively], with a mean difference (95% CI) of ( to ).Conclusion:Chest physiotherapy had a positive impact on the respiratory status of children with mild-to-moderate bronchiolitis.Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT04260919.

Respiratory rate monitoring system based on inorganic halide perovskite humidity sensor

The traditional respiratory rate measurement technologies have several deficiencies, such as subjective appraised results, complicated signal extraction processes, difficult access to equipment, and inconvenience to move due to the wired connection setting. The respiratory airflow can directly reflect the human breath, and the respiratory frequency is usually 1012 breaths/min (1 ventilation every 56 seconds). The humidity difference between exhalation and inhalation can be directly used to measure respiratory rate. In the present work, a wireless respiratory rate monitoring system based on inorganic halide perovskite humidity sensor was developed. The sensor exhibits an ultrasensitive humidity sensing performance, which overcomes the long response/recovery time (> 10 seconds) of the commercial humidity sensors. The system utilized a Zigbee wireless communication to transmit the measurement signal, which separates the signal detection and processing parts, making it easier for the tester to move. The upper computer software was designed and used for data processing to calculate the breathing rate. The system can accurately monitor the respiratory rate in real-time, recognize and alarm the apnea successfully by comparing with a setting threshold value. The test results show that the system can accurately monitor the breathing rate with a maximum error of 1 time per minute. The system possesses great potential for application in respiratory rate monitoring due to its high accuracy, simple operation, portability, and low cost.

Correlation between bronchial dilation test and asthma control level in children with asthma

OBJECTIVE To study the correlation between the bronchial dilation test (BDT) and asthma control level in children with asthma. METHODS A total of 153 children with asthma, aged 5-14 years, who attended the outpatient service from March 2016 to March 2018 were enrolled. According to the presence or absence of atopic constitution, they were divided into an allergic group with 79 children and a non-allergic group with 74 children. The correlation between BDT and Childhood Asthma Control Test (C-ACT) scores was analyzed for both groups. RESULTS All basic pulmonary function parameters were positively correlated with C-ACT scores in the non-allergic group (P < 0.05). Except the forced vital capacity, peak expiratory flow and maximal expiratory flow at 25% vital capacity in percent predicted values, the other pulmonary function parameters were positively correlated with C-ACT scores in the allergic group (P < 0.05). The improvement rates of all BDT parameters (except maximal expiratory flow at 25% vital capacity in the allergic group and maximal expiratory flow at 50% vital capacity in the non-allergic group) were negatively correlated with C-ACT scores in the two groups (P < 0.05). CONCLUSIONS The improvement rate of BDT is well correlated with C-ACT scores in children with asthma, suggesting that BDT can be used as an index for predicting asthma control level.

Lack of association between heart period variability asymmetry and respiratory sinus arrhythmia in healthy and chronic heart failure individuals.

Temporal asymmetry is a peculiar aspect of heart period (HP) variability (HPV). HPV asymmetry (HPVA) is reduced with aging and pathology, but its origin is not fully elucidated. Given the impact of respiration on HPV resulting in the respiratory sinus arrhythmia (RSA) and the asymmetric shape of the respiratory pattern, a possible link between HPVA and RSA might be expected. In this study we tested the hypothesis that HPVA is significantly associated with RSA and asymmetry of the respiratory rhythm. We studied 42 middle-aged healthy (H) subjects, and 56 chronic heart failure (CHF) patients of whom 26 assigned to the New York Heart Association (NYHA) class II (CHF-II) and 30 to NYHA class III (CHF-III). Electrocardiogram and lung volume were monitored for 8 minutes during spontaneous breathing (SB) and controlled breathing (CB) at 15 breaths/minute. The ratio of inspiratory (INSP) to expiratory (EXP) phases, namely the I/E ratio, and RSA were calculated. HPVA was estimated as the percentage of negative HP variations, traditionally measured via the Porta’s index (PI). Departures of PI from 50% indicated HPVA and its significance was tested via surrogate data. We found that RSA increased during CB and I/E ratio was smaller than 1 in all groups and experimental conditions. In H subjects the PI was about 50% during SB and it increased significantly during CB. In both CHF-II and CHF-III groups the PI was about 50% during SB and remained unmodified during CB. The PI was uncorrelated with RSA and I/E ratio regardless of the experimental condition and group. Pooling together data of different experimental conditions did not affect conclusions. Therefore, we conclude that the HPVA cannot be explained by RSA and/or I/E ratio, thus representing a peculiar feature of the cardiac control that can be aroused in middle-aged H individuals via CB.

Nitrification Activity of the Sponge Chondrosia reniformis Under Elevated Concentrations of Ammonium

This study examined the ability of a Mediterranean demosponge Chondrosia reniformis to oxidize exogenous ammonium, simulating N-rich conditions that occur near finfish farms. We hypothesized that as the concentration of ammonium increases in the surrounding seawater, nitrification mediated by microbes associated with C. reniformis will lead to enhancement of ammonium uptake, nitrate excretion and oxygen consumption by the sponge holobiont. To test this hypothesis, we conducted laboratory experiments with C. reniformis explants exposed to ammonium enrichments (300–6667 nM) and to ambient seawater (45–1511 nM ammonium). We analyzed inhaled (IN) and exhaled (EX) water samples for dissolved oxygen, ammonium, nitrates and retention of picoplankton cells. We observed ammonium uptake in nearly half the cases and excretion of nitrate in most experimental outcomes. Yet, the consumption of ammonium and oxygen, as well as the excretion of nitrate by C. reniformis were not related to the concentration of inhaled ammonium, which suggests that the nitrification activity of sponge-associated microbes is not necessarily related to the concentration of ammonium in the surrounding seawater. Further research is required to reveal the sources of nitrate released from sponges and the fate of this nitrate in natural and manipulated ecosystems.

Experimental visualization of expiratory diffusion under face-to-face situation with utterance

Experimental visualization of expiratory diffusion under face-to-face situation with utterance

Hypoxemia in an adolescent: when the cause is between the lines

Spontaneous pneumomediastinum is a rare entity in pediatric age, with multifactorial etiology. A 16-year-old male with multiple allergies (mites, dogs, cats, and grasses), daily smoker (one pack/day for one year), and regular cannabis, cocaine, and amphetamine consumer went to the Emergency Department of the local hospital with cough, dyspnea, chest pain, and fever with 12 hours of evolution. On physical examination, the boy presented facies complaints, polypnea, shortness of breath, extensive subcutaneous emphysema in the cervical region and right hemithorax, and diminished vesicular murmur bilaterally with expiratory wheezing. Chest x-ray was performed, revealing alterations compatible with pneumomediastinum and subcutaneous emphysema in the cervical region. Urine test was positive for tetrahydrocannabinoids. Atopy (IgE levels) study was performed, with positive result, and serological testing was performed for Mycoplasma pneumoniae, showing IgM of 33U/mL and IgG of 25U/mL.In this clinical case, multiple pneumomediastinum triggering/predisposing factors can be identified, including marked smoking habits, acute mycoplasma infection, and inhaled and smoked drug consumption. The aim of this study was to review the pathophysiology/semiology of pneumomediastinum and emphasize the importance of clinical suspicion.

LUNG ULTRASOUND B-LINES CORRELATE WITH STATIC COMPLIANCE IN MECHANICALLY VENTILATED PATIENTS

SESSION TITLE: Insights into the Care of Patients with Respiratory Failure SESSION TYPE: Original Investigations PRESENTED ON: October 18-21, 2020 PURPOSE: Lung ultrasound is a quick, non-invasive, and widely available tool used to assess for a multitude of disease processes Recently, a quick point assessment of B-lines (B-line score) has been shown to be an accurate marker of extra-vascular lung water In mechanically ventilated patients, static lung compliance is calculated as Cstat = VT/(Pplat-PEEP), with VT meaning tidal volume, Pplat plateau pressure, and PEEP positive end expiratory pressure A limitation of this technique is that patients need to be passive on the ventilator to accurately measure PPlat, something which is difficult given efforts to reduce sedation Other techniques, such as esophageal manometry, have been used to estimate transpulmonary pressures, but is limited by being invasive and subject to error Our study sought to determine if the B-line score correlates with lung compliance in mechanically ventilated patients We hypothesized that the B-line score would inversely correlate with static lung compliance METHODS: This was a prospective observational study performed in the medical intensive care units of NYU Langone Health and Bellevue Hospital Center Inclusion criteria included all adult patients requiring mechanical ventilation Exclusion criteria included reasons to have reduced respiratory system compliance from an extrapulmonary etiology: BMI > 35, abdominal hypertension, significant pleural effusions, or pneumothorax Lung ultrasound was performed at 4 points over the anterior chest Each image was independently scored by two intensivists The number of B-lines seen in each window were counted and added together to create the B-line score Static lung compliance was determined using the formula above;inspiratory hold maneuvers were used to obtain plateau pressures RESULTS: A total of 99 observations were performed The mean B-line score was 4 73 +/- 0 60 with a range score from 0 to 25 5 Ultrasound B-line score inversely correlated with static lung compliance (Spearman's r = -0 60, p<0 001), net fluid balance in the 24 hours prior to the scan (Spearman's r = -0 26, p=0 02), and P/F ratio (Spearman's r = -0 37, p<0 001) CONCLUSIONS: Ultrasound B-line score correlates with for static lung compliance in mechanically ventilated patients CLINICAL IMPLICATIONS: Our study demonstrates that an assessment of B-lines on lung ultrasound is an effective marker of important clinical characteristics in mechanically ventilated patients In patients where assessments of these factors are limited, use of this quick and simple B-line score may be clinically useful This is especially true in the recent COVID-19 pandemic, where imaging tests and monitoring may be limited given isolation precautions Whether serial B-line scores in the same patient correlate with clinical improvement in the above-mentioned markers is yet to be determined DISCLOSURES: No relevant relationships by Andrew Lehr, source=Web Response No relevant relationships by Vikramjit Mukherjee, source=Web Response, value=Consulting fee Removed 04/27/2020 by Vikramjit Mukherjee, source=Web Response No relevant relationships by Deepak Pradhan, source=Web Response No relevant relationships by Bishoy Zakhary, source=Web Response