A 28-year-old female patient presented through her primary care physician with symptoms of atypical chest pain and chronic cough. Her pain was described as pleuritic and intermittently radiating to the right arm. Her medical history was significant for recurrent respiratory infections, gastritis, and a left ovarian cyst treated with ipsilateral salpingo-oophorectomy. She denied any history of smoking, known lung disease, or extrapulmonary infections.

Diaphragm flutter is a rare disorder defined by dyspnea and often thoracoabdominal pain associated with rapid rhythmic involuntary contractions of the diaphragm with no effective treatment. A 35-year-old woman's flutter was triggered by increasing the depth of breathing and by (electrical) stimulation of the diaphragm. Medical therapy, phrenic nerve crush, and diaphragm pacer stimulation were ineffective. Since increasing diaphragm activity was a trigger, resting the diaphragm was tried. A manual resuscitator and, subsequently, mouthpiece and nasal noninvasive ventilatory support (NVS) instantaneously halted the flutter for 3 months and almost instantaneously for another 6 months. For 16 months, it has continued to halt flutter with rare episodes when getting out of bed that resolve with up to 40 minutes of NVS. To our knowledge, this is the first case of idiopathic diaphragmatic flutter for which diaphragm rest was used as successful treatment with no adverse effects. This should be tried for future cases.

Normal sleep-related rapid eye movement sleep atonia, reduced lung volumes, reduced chemosensitivity, and impaired airway dilator activity become significant vulnerabilities in the setting of neuromuscular disease. In that context, the compounding effects of respiratory muscle weakness and disease-specific features that promote upper airway collapse or cause dilated cardiomyopathy contribute to various sleep-disordered breathing events. The reduction in lung volumes with neuromuscular disease is further compromised by sleep and the supine position, exaggerating the tendency for upper airway collapse and desaturation with sleep-disordered breathing events. The most commonly identified events are diaphragmatic/pseudo-central, due to a decrease in the rib cage contribution to the tidal volume during phasic rapid eye movement sleep. Obstructive and central sleep apneas are also common. Noninvasive ventilation can improve survival and quality of sleep but should be used with caution in the context of dilated cardiomyopathy or significant bulbar symptoms. Noninvasive ventilation can also trigger sleep-disordered breathing events, including ineffective triggering, autotriggering, central sleep apnea, and glottic closure, which compromise the potential benefits of the intervention by increasing arousals, reducing adherence, and impairing sleep architecture. Polysomnography plays an important diagnostic and therapeutic role by correctly categorizing sleep-disordered events, identifying sleep-disordered breathing triggered by noninvasive ventilation, and improving noninvasive ventilation settings. Optimal management may require dedicated hypoventilation protocols and a technical staff well versed in the identification and troubleshooting of respiratory events.

There is increasing appreciation that mitochondria serve cellular functions beyond oxygen sensing and energy production. Accordingly, it has become important to explore noncanonical roles of mitochondria in normal and pathophysiological processes that influence airway structure and function in the context of diseases such as asthma and COPD. Mitochondria can sense upstream processes such as inflammation, infection, tobacco smoke, and environmental insults important in these diseases and in turn can respond to such stimuli through altered mitochondrial protein expression, structure, and resultant dysfunction. Conversely, mitochondrial dysfunction has downstream influences on cytosolic and mitochondrial calcium regulation, airway contractility, gene and protein housekeeping, responses to oxidative stress, proliferation, apoptosis, fibrosis, and certainly metabolism, which are all key aspects of airway disease pathophysiology. Indeed, mitochondrial dysfunction is thought to play a role even in normal processes such as aging and senescence and in conditions such as obesity, which impact airway diseases. Thus, understanding how mitochondrial structure and function play central roles in airway disease may be critical for the development of novel therapeutic avenues targeting dysfunctional mitochondria. In this case, it is likely that mitochondria of airway epithelium, smooth muscle, and fibroblasts play differential roles, consistent with their contributions to disease biology, underlining the challenge of targeting a ubiquitous cellular element of existential importance. This translational review summarizes the current state of understanding of mitochondrial processes that play a role in airway disease pathophysiology and identifying areas of unmet research need and opportunities for novel therapeutic strategies.

Lung cancer screening with low-dose CT (LDCT) scan was shown to reduce lung cancer mortality in the National Lung Screening Trial, a large randomized controlled trial of high-risk current and former smokers. Despite ongoing uncertainty over the effectiveness of LDCT scan in the real-world setting, the Centers for Medicare and Medicaid Services (CMS) decided to cover LDCT scan as a preventive service. As part of its National Coverage Determination, CMS set forth a series of requirements for reimbursement of LDCT scan, including a counseling and shared decision-making visit prior to a LDCT scan being ordered. During this visit, providers must determine patient eligibility, engage in shared decision-making around LDCT scan, discuss the importance of adherence to screening, and provide smoking cessation counseling (if applicable). Two new billing codes were introduced for the counseling and shared decision-making visit and subsequent LDCT scan. In this review, we summarize the evidence around lung cancer screening and describe practical aspects of the counseling and shared decision-making, including billing considerations. We conclude with a discussion of the greater implications of CMS National Coverage Determination, especially as it pertains to quality assurance around new screening tests.