BACKGROUND: Recent studies have highlighted the recognition of diaphragmatic dysfunction as a significant factor contributing to respiratory disturbances in severely ill COVID-19 patients. In the field of noninvasive respiratory support, high-flow nasal cannula (HFNC) has shown effectiveness in relieving diaphragm dysfunction. This study aims to investigate the diaphragmatic response to HFNC in patients with COVID-19 pneumonia by utilizing ultrasound.
METHODS: This retrospective study was conducted in a medical-surgical intensive care unit (ICU) at a tertiary care center in Buenos Aires, Argentina (Sanatorio de Los Arcos) over a 16-month period (January 2021-June 2022). The study included patients admitted to the ICU with a diagnosis of COVID-19 pneumonia who were deemed suitable candidates for HFNC therapy by the attending physician. Diaphragm ultrasound was conducted, measuring diaphragmatic excursion (DE) both before and during the utilization of HFNC for these patients.
RESULTS: A total of 10 patients were included in the study. A statistically significant decrease in respiratory rate was observed with the use of HFNC (p = 0.02), accompanied by a significant increase in DE (p = 0.04).
CONCLUSIONS: HFNC leads to a reduction in respiratory rate and an increase in DE as observed by ultrasound in patients with COVID-19 pneumonia, indicating promising enhancements in respiratory mechanics. However, further research is required to validate these findings.

OBJECTIVE: Traumatic brachial plexus injury (BPI) is a high-morbidity condition with an escalating incidence. One of the treatment options is neurotization using the ipsilateral phrenic nerve. Therefore, diagnosis of nerve dysfunction is a crucial step in preoperative planning. This study aimed to assess the accuracy and reliability of the fluoroscopic sniff test for preoperative diagnosis of phrenic nerve injury in patients with traumatic BPI.
METHODS: The study was conducted from June 2019 to August 2023 at a tertiary care hospital. A preoperative fluoroscopic sniff test was performed. During brachial plexus surgery, direct phrenic nerve stimulation was conducted as a gold standard of phrenic nerve function. Two nonoperating orthopedic surgeons interpreted the accuracy and reliability of the test.
RESULTS: Seventy-four patients with traumatic BPI (66 males and 8 females) with a median age of 26 years were enrolled. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the fluoroscopic sniff test were 90.9% (95% CI 75.7%-98.1%), 100% (95% CI 91.4%-100%), 100% (95% CI 88.4%-100%), 93.2% (95% CI 82.3%-97.6%), and 95.9% (95% CI 88.6%-99.2%), respectively. Interobserver reliability showed excellent agreement (κ = 1, p < 0.001).
CONCLUSIONS: The fluoroscopic sniff test was proven to be an accurate, reliable, and simple tool to evaluate phrenic nerve function in patients with traumatic BPI. Preoperative testing should be performed to reduce operative time to identify the phrenic nerve as a donor for nerve transfer surgery in cases in which no function is detected from the fluoroscopic sniff test.

Mechanical ventilation (MV) is an essential life-saving technique, but prolonged MV can cause significant diaphragmatic dysfunction due to atrophy and decreased contractility of the diaphragm fibres, called ventilator-induced diaphragmatic dysfunction (VIDD). It is not clear about the mechanism of occurrence and prevention measures of VIDD. Irisin is a newly discovered muscle factor that regulates energy metabolism. Studies have shown that irisin can exhibit protective effects by downregulating endoplasmic reticulum (ER) stress in a variety of diseases; whether irisin plays a protective role in VIDD has not been reported. Sprague-Dawley rats were mechanically ventilated to construct a VIDD model, and intervention was performed by intravenous administration of irisin. Diaphragm contractility, degree of atrophy, cross-sectional areas (CSAs), ER stress markers, AMPK protein expression, oxidative stress indicators and apoptotic cell levels were measured at the end of the experiment.Our findings showed that as the duration of ventilation increased, the more severe the VIDD was, the degree of ER stress increased, and the expression of irisin decreased.ER stress may be one of the causes of VIDD. Intervention with irisin ameliorated VIDD by reducing the degree of ER stress, attenuating oxidative stress, and decreasing the apoptotic index. MV decreases the expression of phosphorylated AMPK in the diaphragm, whereas the use of irisin increases the expression of phosphorylated AMPK. Irisin may exert its protective effect by activating the phosphorylated AMPK pathway.

UNASSIGNED: As common abnormal conditions in clinical practice, hypoxemia and respiratory failure are mainly caused by various respiratory diseases. However, other causes are easily overlooked but deserve more attention from doctors.
UNASSIGNED: A 44-year-old man presented with dyspnea for 10 years. In the early stage, his dyspnea was mild without hypoxemia, and he was misdiagnosed with polycythemia vera due to elevated hemoglobin level. He later developed to respiratory failure but he did not have weakness in his extremities. The positional difference in pulmonary function tests and arterial blood gas analysis led us to identify the respiratory muscle dysfunction. Fatty infiltration of the thigh muscle found by magnetic resonance imaging and muscle biopsies gave us more clues to the causes of diaphragmatic dysfunction. Finally, in combination with his family history and the results of whole exome sequencing, he was diagnosed with hereditary myopathy with early respiratory failure (HMERF, OMIM 603689) caused by a variant in the titin gene (TTN).
UNASSIGNED: We have identified a Chinese family with HMERF due to genetic variants in TTN NM_001256850.1: c.90272C > T, p. Pro30091Leu, located at g.179410829A > G on chromosome 2 (GRCh37), which may be specifically associated with the diagrammatic dysfunction. And hyperhemoglobinemia could serve as a potential sign for the early identification of HMERF.

OBJECTIVE: We aimed to quantify perioperative changes in diaphragmatic function and phrenic nerve conduction in patients undergoing routine thoracic surgery.
METHODS: A prospective observational study was performed in patients undergoing esophageal resection or pulmonary lobectomy. Examinations were carried out the day prior to surgery, 3 days and 10-14 days after surgery. Endpoints for diaphragmatic function included ultrasonographic measurements of diaphragmatic excursion and thickening fraction. Endpoints for phrenic nerve conduction included baseline-to-peak amplitude, peak-to-peak amplitude, and transmission delay. Measurements were assessed on both the surgical side and the non-surgical side of the thorax.
RESULTS: Forty patients were included in the study. Significant reductions in diaphragmatic excursion were seen on the surgical side of the thorax for all excursion measures (posterior part of the right hemidiaphragm, p < 0.001; hemidiaphragmatic top point, p < 0.001; change in intrathoracic area, p < 0.001). Significant changes were seen for all phrenic nerve measures (baseline-to-peak amplitude, p < 0.001; peak-to-peak amplitude, p < 0.001; transmission delay, p = 0.041) on the surgical side. However, significant changes were also seen on the non-surgical side for all phrenic nerve measures (baseline-to-peak amplitude, p < 0.001; peak-to-peak amplitude, p < 0.001; transmission delay, p = 0.022). A postoperative reduction in posterior diaphragmatic excursion of more than 50% was significantly associated with postoperative pulmonary complications (coefficient: 2.69 (95% CI [1.38, 4.01], p < 0.001).
CONCLUSIONS: Thoracic surgery caused a significant unilateral reduction in diaphragmatic excursion on the surgical side of the thorax, which was accompanied by significant changes in phrenic nerve conduction. However, phrenic nerve conduction was also significantly affected on the non-surgical side to a lesser extent, which was not mirrored in diaphragmatic excursion. Our findings suggest that phrenic nerve paresis plays a role in postoperative diaphragmatic dysfunction, which may be a contributing factor in the pathogenesis of postoperative pulmonary complications.
BACKGROUND: NCT04507594.

BACKGROUND: The high morbidity and mortality of tuberculosis has led to the development of numerous therapeutic interventions during the pre-antibiotic era. In 1894, Forlanini proposed the technique of collapse therapy, using spontaneous pneumothorax. In 1926, Bernou developed the oleothorax technique to induce an iatrogenic collapse of the lung through the instillation of oil into the pleural cavity, which was subsequently removed. Nowadays, there are few patients that still represent a living testimony of this historic technique and have been described through traditional radiology.
METHODS: We report the case of a patient with evidence of a right oleothorax that was investigated not only with traditional radiology but also with the use of chest ultrasonography. Ultrasounds were able to show peculiar characteristics of the oleothorax, including its particular echogenicity, the rigidity and static nature of the collection, the presence of peripheral calcifications, and the negative impact of the collection on diaphragmatic mobility and excursion.
CONCLUSIONS: To our knowledge, this is the first report of an ultrasound description of oleothorax. We have observed that ultrasound examination, in cases of basal oleothorax, is able to add information regarding its radiological appearance and physiopathological implications on ventilatory mechanics and diaphragmatic distress.

Dynamic digital radiography (DDR) is a high-resolution radiographic imaging technique using pulsed X-ray emission to acquire a multiframe cine-loop of the target anatomical area. The first DDR technology was orthostatic chest acquisitions, but new portable equipment that can be positioned at the patient\'s bedside was recently released, significantly expanding its potential applications, particularly in chest examination. It provides anatomical and functional information on the motion of different anatomical structures, such as the lungs, pleura, rib cage, and trachea. Native images can be further analyzed with dedicated post-processing software to extract quantitative parameters, including diaphragm motility, automatically projected lung area and area changing rate, a colorimetric map of the signal value change related to respiration and motility, and lung perfusion. The dynamic diagnostic information along with the significant advantages of this technique in terms of portability, versatility, and cost-effectiveness represents a potential game changer for radiological diagnosis and monitoring at the patient\'s bedside. DDR has several applications in daily clinical practice, and in this narrative review, we will focus on chest imaging, which is the main application explored to date in the literature. However, studies are still needed to understand deeply the clinical impact of this method.

OBJECTIVE: Thoracic ultrasound (TUS) has been established as a powerful diagnostic and monitoring tool in the Intensive Care Unit (ICU). However, studies outside the critical care setting are scarce. The aim of this study was to investigate the value of TUS for hospitalized or ambulatory community patients.
METHODS: This was a retrospective study conducted from 2016 to 2020 in the TUS clinic at Heraklion University Hospital. TUS examination was performed using a standard ultrasound machine (EUB HITACHI 8500), and a high-frequency microconvex probe (5-8 MHz). Patients had been referred by their primary physician to address a range of different questions. The various respiratory system entities were characterised according to internationally established criteria.
RESULTS: 762 TUS studies were performed on 526 patients due to underlying malignancy (n = 376), unexplained symptoms/signs (n = 53), pregnancy related issues (n = 42), evaluation of abnormal findings in X-ray (n = 165), recent surgery/trauma (n = 23), recent onset respiratory failure (n = 12), acute respiratory infection (n = 66) and underlying non-malignant disease (n = 25). Pleural effusion was the commonest pathologic entity (n = 610), followed by consolidation (n = 269), diaphragmatic dysfunction/paradox (n = 174) and interstitial syndrome (n = 53). Discrepancies between chest X-ray and ultrasonographic findings were demonstrated in 96 cases. The TUS findings guided invasive therapeutic management in 448 cases and non-invasive management in 43 cases, while follow-up monitoring was decided in 271 cases.
CONCLUSIONS: This study showed that TUS can identify the most common respiratory pathologic entities encountered in hospitalized and community ambulatory patients, and is especially useful in guiding the decision making process in a diverse group of patients.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that can impact any organ in the body. The pathophysiology of shrinking lung syndrome (SLS), a rare pulmonary complication of SLE, remains unknown. The objective of the current case series was to investigate the effects of inspiratory muscle training (IMT) on diaphragm thickness/mobility, respiratory muscle strength, peripheral muscle thickness/strength, and functional exercise capacity in patients with SLE and associated SLS. Three patients with SLE were included in the case series. Respiratory muscle strength, peripheral muscle strength, peripheral muscle thickness, diaphragm muscle thickness, diaphragm muscle mobility, functional exercise capacity, and pulmonary function test were assessed. A significant improvement has been determined in respiratory muscle strength, functional exercise capacity, peripheral muscle strength, peripheral muscle thickness, diaphragm muscle thickness, and diaphragm muscle mobility. This is the first case series showing the beneficial effects of IMT on respiratory muscle strength, diaphragm thickness/mobility, peripheral muscle thickness/strength, and exercise capacity in patients with SLE.

BACKGROUND: Diaphragm dysfunction is common in critically ill patients and associated with poorer outcomes. The function of the diaphragm can be evaluated at the bedside by measuring diaphragmatic excursion using ultrasonography. In this study, we investigated the ability of right-sided diaphragmatic excursion (RDE) to predict the need for invasive mechanical ventilation (IMV).
METHODS: Critically ill patients aged 18 years and older who presented to our emergency department between May 20, 2021 and May 19, 2022 and underwent measurement of RDE within 10 min of arrival were enrolled in this prospective study. The ability of RDE to predict the need for IMV was assessed by multivariable logistic regression and analysis of the area under the receiver-operating characteristic curve (AUROC).
RESULTS: A total of 314 patients were enrolled in the study; 113 (35.9%) of these patients required IMV. An increase of RDE value per each 0.1 cm was identified to be an independent predictor of IMV (adjusted odds ratio 0.08, 95% confidence interval [CI] 0.04-0.17, p < 0.001; AUROC 0.850, 95% CI 0.807-0.894). The RDE cutoff value was 1.2 cm (sensitivity 82.3%, 95% CI 74.0-88.8; specificity 78.1%, 95% CI 71.7-83.6). Time on a ventilator was significantly longer when the RDE was ≤ 1.2 cm (13 days [interquartile range 5, 27] versus 5 days [interquartile range 3, 8], p = 0.006).
CONCLUSIONS: In this study, RDE had a good ability to predict the need for IMV in critically ill patients. The optimal RDE cutoff value was 1.2 cm. Its benefit in patient management requires further investigation.