Clinical Approach to Patients with COVID-19 and Unrecognized Obstructive Sleep Apnea.

Purpose: We conducted a retrospective case series of seven male COVID-19 patients with respiratory failure and suspected OSA based on clinical features to evaluate the effects of undiagnosed obstructive sleep apnea (OSA) on COVID-19 outcomes and the response to a continuous positive airway pressure (CPAP) treatment. Cardiorespiratory polygraphy (CRP) and a continuous positive airway pressure treatment were used for diagnosis and management. They confirmed severe obstructive sleep apnea in all patients (apnea/hypopnea index > 30) and improved overnight oxygenation and symptoms at the 1-month follow-up. Conclusions: Undiagnosed obstructive sleep apnea may negatively impact COVID-19 outcomes by exacerbating respiratory failure. Recognition and treatment with continuous positive airway pressure can optimize the management of such patients.

Arterial blood gases' analysis in elite breath-hold divers at extreme depths.

PURPOSE: To showcase results of arterial blood gases' analysis in elite breath-hold divers sampled at depths where their total lung capacities are below their residual lung volume on surface. METHODS: Three male elite breath-hold divers performed body plethysmographies to determine their lung volumes. Two dives were performed, one on normal inhalation to 60 m of depth and the second on complete exhalation to 10 m of depth. Blood samples were taken on five occasions; before the first dive, at 60 and 10 m of depth and immediately after resurfacing after both dives. RESULTS: Arterial blood gases' analysis at 60 m of depth showed an increase in partial pressures of oxygen and carbon dioxide, a consequent decrease in pH and an increase in concentration of HCO3-. After resurfacing, in two divers, values mostly returned to normal; hypoxemia was observed in one diver. At 10 m of depth, all values showed similar variation, and hypoxemia was observed in the same diver but at depth. Upon resurfacing, all values returned to normal. CONCLUSION: This is the first study performed at depths where the total lung capacities of participants are below their residual lung volumes at the surface. Partial pressure of carbon dioxide increases at depth to higher than normal values causing pH to decrease thus exceeding the buffering potential of the blood. In addition, previous assumptions that maximum depth in breath-hold divers is where total lung capacity is reduced to their residual volume proved wrong as our group of divers had no symptoms after resurfacing.

Haemoptysis in breath-hold divers; where does it come from?

INTRODUCTION: The aim of reporting these two cases is to present visual evidence by bronchoscopy of the origin of haemoptysis in two elite breath-hold divers. CASE REPORTS: Two male elite breath-hold divers of similar physical characteristics presented to our clinic after performing dives of up to 75 and 59 meters of seawater depth for 2:30 and 2:35 (minutes:seconds) respectively. Both patients presented with haemoptysis. Lung ultrasound was performed. The first patient had crackles on chest auscultation, overt pulmonary oedema clinically and 90 ultrasound lung comets. The second patient had no oedema or crackles, but presented with 20 ultrasound lung comets. Video bronchoscopy was performed which showed traces of blood coming from all three segments of the right upper lobe in both patients. The rest of the airways and lungs were intact. CONCLUSIONS: These finding suggest that the apical parts of the lungs are the most prone to deep-dive induced damage. The precise mechanism of lung barotrauma and haemoptysis in breath-hold divers remains to be elucidated. These findings may be of importance for a better understanding of the underlying pathology of haemoptysis.