Diameter and flow velocity changes in small pulmonary vessels due to microembolization

Shirai, Masamitsu; Sada, Kouji; Ninomiya, Ishio

doi:10.1152/jappl.1988.65.1.288

Cited by 7 publications

(2 citation statements)

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“…Also, the P values are smaller for the arterial PO 2 and PCO 2 , although they are still significantly different from the baseline. Because this study used a decrease of regional flow as an indicator of the presence of an embolism, we also cannot say whether another embolism could lodge more proximally in the same blood vessel as a result of reestablishment of flow or even in the continued presence of an occlusion to flow, as has been seen previously (40).…”

Section: Vertical Distributionmentioning

confidence: 89%

“…The total number of microspheres injected per dog was 1.1 ϫ 10 7 (only one of the five injections required 3 ϫ 10 6 microspheres), which would occlude ϳ1% of these vessels. Because it is possible that 15-µm microspheres could lodge in series in a given vessel (40), then even Ͻ1% of the vessels might be occluded by microspheres. N 2 emboli were presumed to be present in a lung piece when there was a Ͼ10% (of baseline) decrease in relative PBF.…”

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confidence: 99%

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Spatial distribution of venous gas emboli in the lungs

Souders¹,

Doshier²,

Polissar³

et al. 1999

Journal of Applied Physiology

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The distribution of gaseous pulmonary emboli is presumed to be determined by their buoyancy. We hypothesized that regional pulmonary blood flow may also influence their distribution. Therefore, pulmonary blood flow was measured in supine, anesthetized dogs with use of 15-microm fluorescent microspheres at baseline and during N(2) embolism. The animals were killed, and the lungs were excised, air-dried, and diced into approximately 2-cm(3) pieces with weights and spatial coordinates recorded. Embolism was defined as a >10% flow decrease relative to baseline. Vertically, the incidence of embolism increased substantially by 6 +/- 1% per additional centimeter in height compared with baseline (P = 0.0003). Embolism also increased radially by 3 +/- 1%/cm from the hilum (P = 0.002). There was a weaker but statistically significant increase in embolism to pieces with greater baseline flow, 9 +/- 2% for every 1. 0 increase in relative baseline flow (P = 0.008). We conclude that the distribution of gaseous emboli is influenced by buoyancy and flow dynamics within the pulmonary vasculature.

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Section: Vertical Distributionmentioning

confidence: 89%

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confidence: 99%

Spatial distribution of venous gas emboli in the lungs

Souders¹,

Doshier²,

Polissar³

et al. 1999

Journal of Applied Physiology

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Comparison of haemodynamic effects during venous air infusion and after decompression in pigs

Vik

Jenssen

Brubakk

1994

Europ. J. Appl. Physiol.

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We have compared haemodynamic effects of venous gas emboli during continuous air infusion into the right atrium and after rapid decompression in pigs. Eight anaesthetized and spontaneously breathing pigs received continuous air infusion at a rate of either 0.05 ml.kg-1.min-1 (six pigs, air infusion group) or 0.10 ml.kg-1.min-1 (two pigs). Another eight pigs (decompression group) underwent a 30-min compression to 5 bar (500 kPa, absolute pressure), followed by a rapid decompression (2 bar.min-1). Haemodynamic variables were measured or calculated, and bubbles in the pulmonary artery were monitored using transoesophageal echocardiography. The results showed less variation in the maximal increase in mean pulmonary arterial pressure (BPa,pulm) during air infusion (0.05 ml.kg-1.min-1) than after decompression, although the mean maximal increase did not differ between the two groups [28.0 mmHg (3.73 kPa), 95% confidence interval (CI) 23.5-32.5, vs 32.0 mmHg (4.27 kPa), 95% CI 25.3-38.7, P = 0.3]. The BPa,pulm stabilized or decreased very slowly after peak values were reached in the air infusion group, whereas the BPa,pulm decreased rapidly during the same period in the decompression group. No significant changes in mean arterial pressure were observed during air infusion (0.05 ml.kg-1.min-1), in contrast to the rapid increase and the subsequent decrease, that appeared after decompression. Finally, the maximal bubble count was much lower in the air infusion group than in most of the pigs in the decompression group. The two pigs that received 0.10 ml.kg-1.min-1 stopped breathing after 5-min infusion, developed arterial hypotension and died.

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Diameter and flow velocity changes of feline small pulmonary vessels in response to sympathetic nerve stimulation

et al. 1994

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Using an X-ray television system, we measured directly changes in the internal diameter (ID), flow velocity, and volume flow of the small pulmonary vessels (100-500 microns ID) in response to electrical sympathetic nerve stimulation (SNS) in anaesthetized cats before and after adrenergic receptor blockade. Flow velocity was obtained by measuring the distance that the leading edge of the contrast medium moved per 0.1 s in the small arteries. Volume flow was obtained from the product of flow velocity and cross-sectional area calculated from the ID of the small arteries. SNS was accomplished with 10- to 15-V square-wave pulses of 2-ms duration at 20-30 Hz for 20-s periods. In response to SNS, arterial ID decreased significantly by 8-13% in the 200- to 500-microns vessels but not in the 100- to 200-microns vessels. In the veins, on the other hand, there was no significant ID decrease in any of the 100- to 500-microns vessels. After alpha-receptor blockade (phentolamine, 2 mg/kg i.v.), there were significant ID increases (4-9%) in the 100- to 500-microns arteries in response to SNS, the maximum increases being in the 100- to 200-microns arteries. After beta-blockade (propranolol, 2 mg/kg i.v.), the ID decrease due to SNS in the 200- to 500-microns arteries was enhanced (24-27%) and, in addition, the 100- to 200-microns arteries exhibited a significant ID decrease (18%). Combined alpha- and beta-blockade completely abolished the ID decrease due to SNS. In the veins, on the other hand, no ID change occurred even after alpha- or beta-blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

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Diameter and flow velocity changes in small pulmonary vessels due to microembolization

Cited by 7 publications

References 0 publications

Spatial distribution of venous gas emboli in the lungs

Spatial distribution of venous gas emboli in the lungs

Comparison of haemodynamic effects during venous air infusion and after decompression in pigs

Diameter and flow velocity changes of feline small pulmonary vessels in response to sympathetic nerve stimulation

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