The behaviour of gas bubbles in blood subjected to an oscillating pressure

Tsujino, T.; Shima, A.

doi:10.1016/0021-9290(80)90034-2

Cited by 14 publications

(6 citation statements)

References 16 publications

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“…These calculations estimated that in static blood 8-m-diameter contrast bubbles would have a life span of Ͻ200 ms. Furthermore, theoretical and experimental work demonstrates accelerated bubble dissolution with increased fluid pressure (54) and flow velocity (65). Thus, during exercise, with increased vascular pressures and blood flow velocity, contrast bubble survival times would likely be even shorter than at rest.…”

Section: Discussionmentioning

confidence: 99%

Exercise-induced intrapulmonary arteriovenous shunting in healthy humans

Eldridge¹,

Dempsey²,

Haverkamp³

et al. 2004

Journal of Applied Physiology

205

245

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We hypothesized that increasing exercise intensity recruits dormant arteriovenous intrapulmonary shunts, which may contribute to the widened alveolar-arterial oxygen difference seen with exercise. Twenty-three healthy volunteers (13 men and 10 women, aged 23-48 yr) with normal lung function and a wide range of fitness (mean maximal oxygen uptake = 126% predicted; range = 78-200% predicted) were studied by agitated saline contrast echocardiography (4-chamber apical view). All 23 subjects had normal resting contrast echocardiograms without evidence of intracardiac or intrapulmonary shunting. However, with cycle ergometer exercise, 21 of 23 (91%) of the subjects showed a delayed (>3 cardiac cycles) appearance of contrast bubbles in the left heart. This pattern is consistent with passage of contrast bubbles through the pulmonary circulation. Because the contrast bubbles are known to be significantly larger than pulmonary capillaries, we propose that they are traveling through direct arteriovenous intrapulmonary shunts. In all cases, the intrapulmonary shunting developed at submaximal oxygen uptakes [%maximal oxygen uptake = 59 +/- 20 (SD)] and once evident persisted at all subsequent work rates. Within 3 min of exercise termination, the contrast echocardiograms with bubble injection showed no evidence of intrapulmonary shunting. These dynamic shunts will contribute significantly to the widened alveolar-arterial oxygen difference seen with exercise. They may also act as a protective parallel vascular network limiting the rise in regional pulmonary vascular pressure while preserving cardiac output during exercise.

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Section: Discussionmentioning

confidence: 99%

Exercise-induced intrapulmonary arteriovenous shunting in healthy humans

Eldridge¹,

Dempsey²,

Haverkamp³

et al. 2004

Journal of Applied Physiology

205

245

View full text Add to dashboard Cite

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“…Meltzer et al (1980) estimated that the survival time for these bubbles is less than 200 ms, and mean whole‐lung transit time in well‐trained endurance athletes has been shown to exceed 2 s at intensities above 90% of (Hopkins et al 1996; Zavorsky et al 2002). As well, bubble dissolution is greater with increasing fluid pressure (Tsujino & Shima, 1980) and increasing flow velocity (Yang et al 1971), both of which occur during incremental exercise. Therefore, it is unlikely that contrasts entering the left ventricle during exercise would be the result of small diameter bubbles passing through the pulmonary capillaries.…”

Section: Discussionmentioning

confidence: 99%

Intra‐pulmonary shunt and pulmonary gas exchange during exercise in humans

Stickland¹,

Welsh

Haykowsky

et al. 2004

The Journal of Physiology

161

196

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In young, healthy people the alveolar-arterial P O 2 difference (A-aDO 2 ) is small at rest, but frequently increases during exercise. Previously, investigators have focused on ventilation/perfusion mismatch and diffusion abnormalities to explain the impairment in gas exchange, as significant physiological intra-pulmonary shunt has not been found. The aim of this study was to use a non-gas exchange method to determine if anatomical intra-pulmonary (I-P) shunts develop during exercise, and, if so, whether there is a relationship between shunt and increased A-aDO 2 . Healthy male participants performed graded upright cycling to 90%V O 2 max while pulmonary arterial (PAP) and pulmonary artery wedge pressures were measured. Blood samples were obtained from the radial artery, cardiac output (Q) was calculated by the direct Fick method and I-P shunt was determined by administering agitated saline during continuous 2-D echocardiography. A-aDO 2 progressively increased with exercise and was related toQ (r = 0.86) and PAP (r = 0.75). No evidence of I-P shunt was found at rest in the upright position; however, 7 of 8 subjects developed I-P shunts during exercise. In these subjects, point bi-serial correlations indicated that I-P shunts were related to the increased A-aDO 2 (r = 0.68),Q (r = 0.76) and PAP (r = 0.73). During exercise, intra-pulmonary shunt always occurred when A-aDO 2 exceeded 12 mmHg andQ was greater than 24 l min −1 . These results indicate that anatomical I-P shunts develop during exercise and we suggest that shunt recruitment may contribute to the widened A-aDO 2 during exercise.

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“…Depending on the degree of saturation of the surrounding fluid, an 8-m microbubble should dissolve in 190 -550 ms in static blood (34,56,57). Considering that the mean pulmonary capillary transit time from rest to maximal exercise (30 l/min) ranges from 750 to 450 ms, respectively, the significantly increased pressures and flows will only further accelerate the time to microbubble dissolution (44,57,58). For these reasons, small-diameter microbubbles rapidly collapse, while the sieve action of the pulmonary capillary bed filters out large-diameter microbubbles such that in the absence of any right-to-left shunt no microbubbles appear in the left heart.…”

Section: Methodsmentioning

confidence: 99%

“…Effect of initial gas bubble composition on detection of inducible intrapulmonary arteriovenous shunt during exercise in normoxia, hypoxia, or hyperoxia. J Appl Physiol 110: [35][36][37][38][39][40][41][42][43][44][45]2011. First published September 16, 2010; doi:10.1152/japplphysiol.00145.2010.-Concern has been raised that altering the fraction of inspired O2 (FIO 2 ) could accelerate or decelerate microbubble dissolution time within the pulmonary vasculature and thereby invalidate the ability of saline contrast echocardiography to detect intrapulmonary arteriovenous shunt in subjects breathing either a low or a high FI O 2 .…”

mentioning

confidence: 99%

Effect of initial gas bubble composition on detection of inducible intrapulmonary arteriovenous shunt during exercise in normoxia, hypoxia, or hyperoxia

Elliott

Choi

Laurie

et al. 2011

Journal of Applied Physiology

119

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Concern has been raised that altering the fraction of inspired O₂ (Fi(O₂)) could accelerate or decelerate microbubble dissolution time within the pulmonary vasculature and thereby invalidate the ability of saline contrast echocardiography to detect intrapulmonary arteriovenous shunt in subjects breathing either a low or a high Fi(O₂). The present study determined whether the gaseous component used for saline contrast echocardiography affects the detection of exercise-induced intrapulmonary arteriovenous shunt under varying Fi(O₂). Twelve healthy human subjects (6 men, 6 women) performed three 11-min bouts of cycle ergometer exercise at 60% peak O₂ consumption (Vo(2peak)) in normoxia, hypoxia (Fi(O₂) = 0.14), and hyperoxia (Fi(O₂) = 1.0). Five different gases were used to create saline contrast microbubbles by two separate methods and were injected intravenously in the following order at 2-min intervals: room air, 100% N₂, 100% O₂, 100% CO₂, and 100% He. Breathing hyperoxia prevented exercise-induced intrapulmonary arteriovenous shunt, whereas breathing hypoxia and normoxia resulted in a significant level of exercise-induced intrapulmonary arteriovenous shunt. During exercise, for any Fi(O₂) there was no significant difference in bubble score when the different microbubble gas compositions made with either method were used. The present results support our previous work using saline contrast echocardiography and validate the use of room air as an acceptable gaseous component for use with saline contrast echocardiography to detect intrapulmonary arteriovenous shunt during exercise or at rest with subjects breathing any Fi(O₂). These results suggest that in vivo gas bubbles are less susceptible to changes in the ambient external environment than previously suspected.

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The behaviour of gas bubbles in blood subjected to an oscillating pressure

Cited by 14 publications

References 16 publications

Exercise-induced intrapulmonary arteriovenous shunting in healthy humans

Exercise-induced intrapulmonary arteriovenous shunting in healthy humans

Intra‐pulmonary shunt and pulmonary gas exchange during exercise in humans

Effect of initial gas bubble composition on detection of inducible intrapulmonary arteriovenous shunt during exercise in normoxia, hypoxia, or hyperoxia

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