Surgical correction of abdominal muscle diastasis may decrease intra-abdominal volume and increase intra-abdominal pressure. The induced changes may ultimately lead to respiratory compromise. In abdominoplasty, one of the most frequently performed esthetic procedures, those changes are believed to be transient and clinically insignificant. We describe a case where acute change in respiratory physiology after abdominoplasty led to severe respiratory failure with significantly decreased pulmonary compliance in a young and otherwise healthy patient. In this case mechanical ventilation failed to improve compliance, and reversal of abdominoplasty was required to restitute pulmonary function.

Elevated peak inspiratory pressures (PIPs) cause harm via hypoventilation, barotrauma, and hemodynamic instability. Heat and moisture exchangers (HMEs) are used during mechanical ventilation to prevent heat loss, dehydration of airway mucosa, and accumulation of dried secretions. Multiple reports detail sudden HME occlusions causing increased PIPs. We describe 4 cases of gradually increasing PIPs from progressive HME obstruction that occurred within 6 months of an institutional change to a newer model. HME obstruction should be considered when PIPs are elevated. Alternative heat and moisture preservation strategies should be contemplated, as HMEs increase airflow resistance and add another point of possible malfunction.

In this case study, we evaluate the unique physiological profiles of two world-champion breath-hold divers. At close to current world-record depths, the extreme physiological responses to both exercise and asphyxia during progressive elevations in hydrostatic pressure are profound. As such, these professional athletes must be capable of managing such stress, to maintain performing at the forefront human capacity. In both divers, pulmonary function before and after deep dives to 102 m and 117 m in the open sea was assessed using noninvasive pulmonary gas exchange (indexed via the O2 deficit, which is analogous to the traditional alveolar to arterial oxygen difference), ultrasound B-line scores, airway resistance, and airway reactance. Hydrostatic-induced lung compression was also quantified via spirometry. Both divers successfully performed their dives. Pulmonary gas exchange efficiency was impaired in both divers at 10 min but had mostly restored within a few hours. Mild hemoptysis was transiently evident immediately following the 117-m dive, whereas both divers experienced nitrogen narcosis. Although B-lines were only elevated in one diver postdive, reductions in airway resistance and reactance occurred in both divers, suggesting that the compressive strain on the structural characteristics of the airways can persist for up to 3.5 h. Marked echocardiographic dyssynchrony was evident in one diver after 10 m of descent, which persisted until resolving at ∼77 m during ascent. In summary, despite the enormous hydrostatic and physiological stress to diving beyond 100 m on a single breath, these data provide valuable insight into the extraordinary capacity of those at the pinnacle of apneic performance.NEW & NOTEWORTHY This study shows that world-champion breath-hold divers demonstrate incredible tolerability to extreme levels of hydrostatic-induced lung compression. Immediately following dives to >100 m, there were acute impairments in pulmonary gas exchange efficiency, mild accummulation of extravascular lung fluid, noticable intrathoracic discomfort, and evident nitrogen narcosis, however, within a few hours, these had all mostly resolved.

Acute respiratory distress syndrome virus-2 (SARS-CoV-2) responsible for coronavirus disease 2019 (COVID-19) infection, which causes global public health emergencies, has sped widely for more than 5 months and has the risk of long-term transmission. No effective treatment has been discovered to date. In the cases we report, the patient continued to deteriorate even after administration of antiviral drugs such as lopinavir/ritonavir, interferon-α, and ribavirin, as well as intravenous injection of meropenem, methylprednisolone, and immunoglobulin. So, we infused the patient with convalescent plasma (CP), and the absolute lymphocyte count increased the next day and returned to normal on the fourth day. Followed by intravenous infusion of mesenchymal stem cells (MSCs), bilateral infiltrates were absorbed and the pulmonary function was significantly improved. We note that the intravenous infusion of CP and MSCs for the treatment of severe COVID-19 patients may have synergistic characteristics in inhibiting cytokine storm, promoting the repair of lung injury, and recovering pulmonary function. We hope to provide a reference for the research direction of COVID-19 clinical strategies.

Cough is a troublesome and difficult-to-treat symptom that accompanies a diverse range of pulmonary and extrapulmonary conditions. Although considerable advances have been made over recent years in basic cough biology, this has not translated into improved clinical management. A major challenge has been in understanding the heterogeneity underlying the development and persistence of chronic cough in different patients. We present evidence that such heterogeneity begins with the multiple peripheral and central neural pathways capable of eliciting cough and associated respiratory behaviours, and extends to incorporate the diversity of diseases that underlie cough and the clinical phenotypic and pathological endotypic presentations that can vary substantially between individual patients with cough. A better understanding of how these sources of heterogeneity are expressed across individual patients with chronic cough is needed to better predict the efficacy of clinical management strategies and of specifically targeted therapies, which will facilitate the development of more personalised clinical approaches to treat patients with chronic cough.

Scimitar syndrome is a rare complex of congenital anomalies of the cardiopulmonary system. In patients with scimitar syndrome, the right pulmonary vein abnormally drains into the inferior vena cava, right atrium, coronary sinus, azygos vein, portal vein, or hepatic vein. The syndrome gets its name from the Turkish sword-like image that appears on chest x-ray. Some patients with scimitar syndrome survive in adulthood undiagnosed. Herein, we discuss positional oxygenation and hemodynamic changes associated with scimitar syndrome, especially in the left lateral decubitus position, detected during preoperative anesthetic examination in an adult patient who underwent general anesthesia for left mastectomy.

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BACKGROUND: The point in the airway that allows the smallest maximal flow is known as the \"choke point\". The tube law describes the velocity of the expired air, which cannot exceed the wave-speed. Flow limitation during forced expiration is affected by the relationship between the transmural pressure (Ptm) and cross-sectional area (A) of the airway. Wave speed is dependent on the stiffness of the airway wall, as well as on the cross-section of the airway itself (dA/dPtm).
METHODS: Airway stenting at the wave-speed, flow-limiting segment (choke point) is assessed by using a catheter, via the working channel of a stereoscopic bronchoscope, to measure the difference between lateral pressure and pleural pressure.
RESULTS: Based on the wave-speed concept of maximal expiratory flow limitation, stenting at the choke point increased the cross-sectional area and supported the weakened airway wall, thus improving expiratory flow limitation and relieving dyspnea.
CONCLUSIONS: To ensure correct stent positioning and thus optimal functional benefit, it is important to locate the exact position of tracheobronchial stenosis.

Glottic obstruction is a major cause of dyspnea. Without understanding the normal function of the glottis in breathing, treating dyspnea does not restore normal physiology. Therefore, we designed a computational fluid dynamics (CFD) model that tested the respiratory cycle in larynges with normal glottis and congenital glottic web (CGW). A CGW case and a control subject (CC) were selected from the computed tomography (CT) archive. 3D computational models of the larynges with structured boundary layer were constructed from axial CT images after mesh refinement study. CFD analyses were based on the Reynolds-averaged Navier-Stokes approach. Incompressible flow solver (pressure-based) and SST k-w turbulence model were chosen for this study. To simulate a real-time breathing process, time varying flow rate boundary condition was derived from the spirometer of a healthy, non-smoking woman. Glottic areas were measured as 51.64 and 125.43 mm(2) for the CGW patient and CC, respectively. Time-dependent velocity contours and streamlines for the CC and CGW patient were drawn. The CC showed uniform flow, all through the inspiration and expiration phases. However, the CGW patient showed separation of flow at the glottis level, which caused areas of stagnation in the supraglottis (during expiration) and the subglottis and trachea (during inspiration). Specialized geometry of the normal larynx maintained uniform flow with low shear stress values on the wall even at high mass flow rates. Distortion of this geometry may cause obstruction of flow at multiple levels and, therefore, should be evaluated at multiple levels.

BACKGROUND: Facial coverings (e.g., balaclavas, niqabs, medical/surgical masks, respirators, etc.), that impose low levels of airflow resistive loads, are worn by millions of pregnant women worldwide, but little data exist addressing their impact on pregnancy-associated cardiovascular and pulmonary responses.
METHODS: 16 pregnant and 16 non-pregnant women were monitored physiologically (heart rate, blood pressure, mean arterial pressure, total peripheral resistance, stroke volume, cardiac output, oxygen saturation, transcutaneous carbon dioxide, fetal heart rate) and subjectively (exertion) for 1 h of mixed sedentary postural activity (sitting, standing) and moderate exercise (bicycle ergometer) with and without wearing N95 filtering facepiece respirators with filter resistive loads of 94.1 Pa (9.6 mm H2O) - 119.6 Pa (12.2 mm H2O) pressure.
RESULTS: The external airflow resistive loads were associated with increases in diastolic pressure (p = 0.004), mean arterial pressure (p = 0.01), and subjective exertion score (p < 0.001) of all study subjects. No significant differences were noted with the external resistive loads between the pregnant and non-pregnant groups for any cardiovascular, pulmonary and subjective variable over 1 h.
CONCLUSIONS: Low external airflow resistive loads, during combined sedentary postural activity and moderate exercise over 1 h, were associated with increases in the diastolic and mean arterial pressures of all study subjects, but pregnancy itself was not associated with any significant differences in physiologic or subjective responses to the external airway resistive loads utilized in the study.