Undersea biomedical research最新文献_第2页

Paradoxical air embolism in pigs with a patent foramen ovale. 猪卵圆孔未闭的矛盾性空气栓塞。

Undersea biomedical research Pub Date : 1992-09-01

A Vik, B M Jenssen, A O Brubakk

{"title":"Paradoxical air embolism in pigs with a patent foramen ovale.","authors":"A Vik, B M Jenssen, A O Brubakk","doi":"","DOIUrl":"","url":null,"abstract":"Recent studies have indicated that divers with a patent foramen ovale (PFO) are at risk of developing some forms of decompression sickness. Thus, the objective of the present study was to investigate if the occurrence of paradoxical air embolism (PAE) was enhanced in pigs with a PFO compared to the occurrence in pigs without such a defect. Out of 54 pigs, 18 had a PFO (group PFO), and the other 36 composed the controls (group C). The pigs were anesthetized, mechanically ventilated, and received venous air infusion at four different rates (0.050, 0.075, 0.100, and 0.200 ml.kg-1.min-1). PAE was monitored by use of a transesophageal echocardiographic probe to detect if any arterial air bubbles were present in the left atrium or the aorta. We found that PAE appeared at a lower infusion rate in group PFO than in group C. When PAE occurred, the mean pulmonary arterial pressure and the mean arterial pressure were significantly higher in pigs with a PFO than in the control pigs. Finally, the infused air volume per kilogram of body weight in group PFO was significantly lower than that observed in group C. The results demonstrated that the risk of PAE occurring in mechanically ventilated pigs with a PFO was greater compared to the risk observed in pigs without a PFO.","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"19 5","pages":"361-74"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12682728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Xenon washout from the rabbit femur during short hyperbaric exposures. 兔股骨在短时间高压暴露时的氙气冲洗。

Undersea biomedical research Pub Date : 1992-09-01

T R Davis

引用次数: 0

Intravascular bubble composition in guinea pigs: a possible explanation for differences in decompression risk among different gases. 豚鼠血管内气泡组成:不同气体间减压风险差异的可能解释。

Undersea biomedical research Pub Date : 1992-09-01

R S Lillo, M E Maccallum, J M Caldwell

{"title":"Intravascular bubble composition in guinea pigs: a possible explanation for differences in decompression risk among different gases.","authors":"R S Lillo, M E Maccallum, J M Caldwell","doi":"","DOIUrl":"","url":null,"abstract":"Differences in risk of decompression sickness (DCS) that have been observed among inert gases may reflect differences in gas solubility or diffusivity or both. A higher risk gas might generate a larger volume of evolved gas during decompression, thereby increasing the probability of DCS. If this hypothesis is correct, the composition of bubbles that develop during decompression should reflect such gas differences. Unanesthetized guinea pigs were compressed to depths ranging from 250 to 350 fsw with air, He-O2 (21% O2) or one of a number of N2-He-O2 or N2-Ar-O2 mixtures (21% O2). Animals were held at depth from 15 to 60 min, then decompressed slowly (60 fsw/min) or rapidly (less than 15 s) to 5 fsw. If severe DCS developed, as judged by changes in physiologic variables, death usually occurred quickly. Gas/blood samples were then immediately withdrawn from the right atrium or the inferior vena cava, and the gas phase analyzed for He, N2, Ar, O2, and CO2 via gas chromatography. Bubbles from all dives contained 5-9% CO2, 1-4% O2, with the balance inert gas. Bubbles after N2-He-O2 dives contained substantially more N2 than He (up to 1.9 times more) compared to the dive mixture; bubbles after N2-Ar-O2 dives contained more Ar than N2 (up to 1.8 times more). For N2-He-O2 dives, the actual inert gas makeup of bubbles was dependent on the time-at-depth and the decompression profile. Results may reflect differences among He, N2, and Ar in tissue solubility/diffusivity and gas exchange rates, and support the rank order of increasing DCS risk (He less than N2 less than Ar) and rate of gas exchange (N2 less than He) observed previously during rat dives.","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"19 5","pages":"375-86"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12529202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Cerebral blood flow distribution during exposure to 5 bar oxygen in awake rats. 清醒大鼠暴露于5bar氧时的脑血流分布。

Undersea biomedical research Pub Date : 1992-09-01

G W Bergö, I Tyssebotn

{"title":"Cerebral blood flow distribution during exposure to 5 bar oxygen in awake rats.","authors":"G W Bergö, I Tyssebotn","doi":"","DOIUrl":"","url":null,"abstract":"The regional cerebral blood flow (rCBF) and cardiac output (CO) were measured in conscious rats by the microsphere method during control, after 5 and 60 min at 5 bar O2, and 5 min after decompression to air. The arterial acid-base balance was essentially unchanged during hyperbaric O2 and after decompression, except for a slightly reduced CO2 and HCO3 during the O2 exposure. The heart rate (HR) fell at 1 bar O2, continued to fall during compression, and remained low. A marked HR rise occurred in air after decompression. The systolic arterial pressure (AP) increased, while mean AP was constant during the O2 exposure. The CO and total cerebral blood flow fell in proportion to the arterial O2 content increase. The rCBF was unevenly distributed in control, and fell to a disparate degree and remained low in some regions during O2 exposure. Due to the rCBF fall, the O2 supply was limited, the glucose supply was reduced, and CO2 and heat transport probably were limited, suggesting a labile metabolic state locally in the brain. After decompression, blood flow remained low in several regions, making hypoxia likely for a considerable time in several brain areas, whereas the rest of the brain had normalized or increased blood flow. The HR and systolic AP remained high for at least 30 min after decompression.","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"19 5","pages":"339-54"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12529200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evaluation of energy requirements from body mass, lean body mass, fat content, and energy intake in GUSI dives. 评估GUSI潜水中体重、瘦体重、脂肪含量和能量摄入的能量需求。