Gas flow during bronchoscopic ablation therapy causes gas emboli to the heart: a comparative animal study.

BACKGROUND: Thermal ablation is one of the most commonly used modalities to treat central airway obstruction. Both laser and argon plasma coagulation (APC) have been reported to cause gas emboli and cardiac arrest. We sought to determine whether bronchoscopic ablation therapy can result in systemic gas emboli, correlate their presence with the rate of gas flow, and establish whether a zero-flow (ZF) modality would result in the significant reduction or elimination of emboli. METHODS: CO(2) laser delivered through a photonic bandgap fiber (PBF) and APC were applied in the trachea and mainstem bronchi of six anesthetized sheep at varying dosages and gas flow rates. Direct epicardial echocardiography was used to obtain a four-chamber view and detect gas emboli. RESULTS: The presence of gas flow accompanying APC and the CO(2) laser with forward flow correlated significantly with the appearance of gas bubbles in the atria. A definite dose response was observed between the gas flow rate and the number of bubbles seen. When the CO(2) laser was delivered through a PBF with ZF to the trachea or bronchi, no bubbles were observed. CONCLUSION: Bronchoscopic thermal ablation therapy using gas flow is associated with gas emboli in a dose-dependent fashion. The use of the flexible PBF with ZF is not associated with the development of gas emboli. Further study is required to determine whether a clinically safe threshold of gas emboli exists, and the relationships among the pathologic depth of tissue destruction, gas flow, pulse duration, and the development of gas emboli.

Magnetic resonance imaging showed no signs of overuse or permanent injury to the lumbar sacral spine during a Special Forces training course.

BACKGROUND CONTEXT: Special Forces training is even more demanding than that of elite athletes. The training includes grueling physical activity and periods of sleep deprivation. The soldiers routinely carry heavy loads up to 40% of their body weight on their backs while running and marching for distances up to 90 km. PURPOSE: Our purpose was to find out if Special Forces recruits are able to complete the preparatory Navy Seals training program without sustaining magnetic resonance imaging (MRI) signs of overuse or irreversible injury to their backs. STUDY DESIGN/SETTING: Prospective cohort study. We performed MRI scans before and after 14 weeks of Navy Seals preparatory training course. PATIENT SAMPLE: Ten soldiers underwent MRI of their lumbar sacral spines and right knees before and after the completion of Navy Seals preparatory training. OUTCOME MEASURES: Physiologic measures. Lumbar sacral spine and knee MRI tests were performed before and after the training to identify changes in the spinal discs, facet joints, pars interarticularis, vertebral bodies, knee articular cartilage, ligaments, knee menisci, and the presence or absence of soft tissue and/or bone edema. METHODS: We investigated the difference in spine and knee pathology before and after a 14-week Navy Seals preparatory training course by using MRI criteria. The recruits participating in the study were monitored for acute and overuse injuries every 3 to 4 weeks. RESULTS: Before the training, seven out of ten spine MRI scans were normal. Two showed small L5-S1 disc bulges, one of them with concomitant Scheuermann's disease. Another soldier's MRI showed L1-L4 mild Scheuermann's disease. Follow-up MRI showed no spinal changes. Before the training, one knee had a small lateral femoral condyle cartilage lesion. Nine of ten knees had prepatellar swelling, five had increased joint fluid, and two bone edema. Follow-up magnetic resonance imaging showed improvement in the prepatellar swelling in eight soldiers, no change in one soldier, and increased knee effusion and a new medial femoral condyle bone edema in another. The lateral femoral condyle lesion remained unchanged. CONCLUSIONS: According to MRI criteria, the soldiers in this study completed the 14-week training, which involved loading of their spines far beyond the levels recommended by the US National Institute for Occupational Safety and Health without sustaining irreversible damage to their spines or knees. Although the subjects' knees showed signs of overuse injury, their backs did not.

[Exercise induced hyponatremia].

A normal water-electrolyte balance is essential for normal function of body systems during physical activity. During recent years, awareness of the importance of drinking amongst athletes and Israeli Defense Force (IDF) soldiers, in particular, has been highlighted. A large number of athletes tend to drink prior to, during and after their exercise in order to enhance physical abilities and to prevent heat casualties and dehydration. However, excessive water consumption combined with sweat induced electrolytes loss during physical activity, may cause hyponatremia in extreme cases. Recently, several cases of exercise induced hyponatremia were reported in the IDF, resulting from improper water consumption. In this article, we describe a clinical case of exercise-induced hyponatremia in a soldier and a review of the literature, including the etiology, clinical characterization and recommended treatment. Moreover, water consumption recommendations with regard to physical activity are presented. The application of such recommendations may prevent future events of exercise-induced hyponatremia.