The study goal was to evaluate responses in humans following decompression from open-water SCUBA diving with the hypothesis that exertion underwater and use of a breathing mixture containing more oxygen and less nitrogen (enriched air nitrox) would alter annexin V-positive microparticle (MP) production and size changes and neutrophil activation, as well as their relationships to intravascular bubble formation. Twenty-four divers followed a uniform dive profile to 18 m of sea water breathing air or 22.5 m breathing 32% oxygen/68% nitrogen for 47 min, either swimming with moderately heavy exertion underwater or remaining stationary at depth. Blood was obtained pre- and at 15 and 120 min postdive. Intravascular bubbles were quantified by transthoracic echocardiography postdive at 20-min intervals for 2 h. There were no significant differences in maximum bubble scores among the dives. MP number increased 2.7-fold, on average, within 15 min after each dive; only the air-exertion dive resulted in a significant further increase to 5-fold over baseline at 2 h postdive. Neutrophil activation occurred after all dives. For the enriched air nitrox stationary at depth dive, but not for other conditions, the numbers of postdive annexin V-positive particles above 1 μm in diameter were correlated with intravascular bubble scores (correlation coefficients ∼0.9, P < 0.05). We conclude that postdecompression relationships among bubbles, MPs, platelet-neutrophil interactions, and neutrophil activation appear to exist, but more study is required to improve confidence in the associations.

Arterialization of gas bubbles after decompression from scuba diving has traditionally been associated with pulmonary barotraumas or cardiac defects, such as the patent foramen ovale. Recent studies have demonstrated the right-to-left passage of bubbles through intrapulmonary arterial-venous anastamoses (IPAVA) that allow blood to bypass the pulmonary microcirculation. These passages open up during exercise, and the aim of this study is to see if exercise in a postdiving period increases the incidence of arterialization. After completing a dive to 18 m for 47 min, patent foramen ovale-negative subjects were monitored via transthoracic echocardiography, within 10 min after surfacing, for bubble score at rest. Subjects then completed an incremental cycle ergometry test to exhaustion under continuous transthoracic echocardiography observation. Exercise was suspended if arterialization was observed and resumed when the arterialization cleared. If arterialization was observed a second time, exercise was terminated, and oxygen was administered. Out of 23 subjects, 3 arterialized at rest, 12 arterialized with exercise, and 8 did not arterialize at all even during maximal exercise. The time for arterialization to clear with oxygen was significantly shorter than without. Exercise after diving increased the incidence of arterialization from 13% at rest to 52%. This study shows that individuals are capable of arterializing through IPAVA, and that the intensity at which these open varies by individual. Basic activities associated with SCUBA diving, such as surface swimming or walking with heavy equipment, may be enough to allow the passage of venous gas emboli through IPAVA.

BackgroundSeveral studies have suggested that idiopathic pulmonary fibrosis (IPF) may be related to repeated aspiration of gastric contents over long periods of time. We aimed to investigate differences between pH measured directly in the lung, and biomarkers of acute inflammation in patients with newly diagnosed IPF and in patients with newly diagnosed GERD.Material/MethodsAll subjects (N=61) underwent collection of medical history, physical examination, pulmonary function testing, bronchoscopy, endoscopy, arterial blood gas analyses, and biochemical testing.ResultsPreviously diagnosed GERD was found in 56.7%, typical symptoms of reflux in 80%, and Helicobacter pylori in gastric biopsy specimens in 76.6% of the cases. pH in peripheral branches of bronchi in the cases was 5.32±0.44 and was 6.27±0.31 (p<0.001) in the control group. The average values of LDH, ALP, and CRP in bronchoalveolar aspirate and in serum, as well as TNF-α in bronchoalveolar aspirate, were significantly higher in IPF patients.ConclusionsThe more acidic environment in the bronchoalveolar aspirate of the IPF subjects could contribute to the development or progression of IPF, possibly via changes in local metabolism or by damaging local cells and tissue. However, further studies with larger numbers of patients are required to clarify the role of gastric fluid aspiration in IPF pathogenesis. Our preliminary work has identified inflammatory biomarkers LDH, ALP, and TNF-α as potentially important in the pathologic processes in IPF. Further research is needed to determine their importance in clinical intervention and patient care.

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Localized interlobar effusions in congestive heart failure (phantom or vanishing lung tumor/s) is/are uncommon but well known entities. An 83-year-old man presented with shortness of breath, swollen legs, and dry cough enduring five days. Chest-X-ray (CXR) revealed massive sharply demarked round/oval homogeneous dense shadow 10 × 7 cm in size in the right inferior lobe. The treatment with the loop diuretics and fluid intake reduction resulted in complete resolution of the observed round/oval tumor-like image on the control CXR three days later. Radiologic appearance of such a mass-like configuration in patients with congestive heart failure demands correction of the underlying heart condition before further diagnostic investigation is performed to avoid unnecessary, expensive, and possibly harmful diagnostic and treatment errors.