Gas Bubble Detection in Fluid Lines by Means of Pulsed Doppler Ultrasound

Hatteland, K; Semb, Bjarne K. H.

doi:10.3109/14017438509102706

Cited by 24 publications

(14 citation statements)

References 4 publications

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“…3a). This top corresponded to an air bubble size of 50 µm in diameter because the acoustic impedance for glass spheres of the size of 200 µm corresponded to this size (5,6). The top in level 5 for 6‐dB moderation resulted in that air bubbles are sorted as follows: level 1 is 5–15 µm, level 2 is 15–25 µm, level 3 is 25–35 µm, level 4 is 35–45 µm, level 5 is 45–55 µm, level 6 is 55–65 µm, level 7 is 65–75 µm, level 8 is 75–85 µm, and level 9 represents air bubbles of the size 85 µm and larger (Fig.…”

Section: Resultsmentioning

confidence: 99%

Air Bubbles Pass the Security System of the Dialysis Device Without Alarming

Jönsson¹,

Karlsson²,

Forsberg

et al. 2007

Artificial Organs

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During hemodialysis microembolic findings have been noted after the venous chamber (subclavian vein). The aim of this study was to evaluate if air could pass the venous chamber and, if so, if it passes the safety-system detector for air-infusion without triggering an alarm. Various in vitro dialysis settings were performed using regular dialysis devices. A dextran fluid was used instead of blood to avoid the risk of development of emboli. Optical visualization as well as recirculation and collection of eventual air into an intermediate bag were investigated. In addition, a specifically designed ultrasound monitor was placed after the venous air trap to measure the presence of eventual microbubbles. Speed of dialysis fluid was changed, as was the level of the fluid in the air trap. Thereby a fluid level was considered "high" if it was close to the top of the air trap and "low" if it was around the mid part of the air trap. By optical vision microbubbles were seen at the bottom of the air trap and could pass the air trap towards the venous line without alarming. During recirculation several mL of air were collected in an intermediate bag after the venous line. Ultrasound monitoring exhibited the presence of microbubbles of the size of approximately 5 microm upwards passing to the venous line in all runs performed. Amount of bubbles differed between devices and in general an increased fluid speed correlated significantly with the increased counts of microbubbles/min. No alarming of the detector occurred. A more concentrated fluid allowed higher counts/min when flow was increased to 600 mL/min. Data revealed that air passes the safety-sensor in the air trap without alarming. The presence of air increased in general with fluid speed and a lower fluid level in the air trap. Differences were present between devices. If this affects the patients has to be elucidated.

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Section: Resultsmentioning

confidence: 99%

Air Bubbles Pass the Security System of the Dialysis Device Without Alarming

Jönsson¹,

Karlsson²,

Forsberg

et al. 2007

Artificial Organs

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“…The center for each detection level (Ranges 1–8) was for Range 1, 5 µm; Range 2, 10 µm; Range 3, 15 µm; Range 4, 20 µm; Range 5, 25 µm; Range 6, 30 µm; Range 7, 35 µm; and Range 8, 40 µm all with an SD of ±2.5 µm. Range 9 represented detection level for bubbles above 42.5 µm (8).…”

Section: Methodsmentioning

confidence: 99%

The Sensor in the Venous Chamber Does Not Prevent Passage of Air Bubbles During Hemodialysis

Stegmayr¹,

Forsberg

Jönsson³

et al. 2007

Artificial Organs

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We previously showed, in vitro, that micro bubbles pass the air trap without inducing an alarm. The aim was to investigate if micro bubbles bypass the detector during hemodialysis (HD). During HD (40 patients, 47 HD sessions, 231 measurements), an ultrasound detector was fixed just after the venous air trap. Micro bubble size was measured in the range from 5 microm up to >42.5 microm. Blood flow was at a mean 346 mL/min (SD +/- 57). The mean of all micro bubbles per minute, without inducing an alarm, was at start 128 (range 0-769). Measurements revealed the presence of micro bubbles in all of the series and in 90% of the measurements. There was no difference between start and end of the same dialyses. There was a correlation between blood flow and extent of micro bubbles for the smaller sizes and the sum of all bubbles (r > or = 0.29, P < or = 0.026). Micro bubbles passed the air trap without alarming. Most bubbles were approximately 5 microm.

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“…for this reason, research results on this basic problem have been reported in both materials science literature [1] and medical journals [2], [3].…”

mentioning

confidence: 99%

“…Gas bubbles have been also characterized using pulsed doppler ultrasound [3]. doppler shift gives the bubble velocity and the reflected energy from the bubbles is proportional to the bubble size.…”

mentioning

confidence: 99%

Mesh-free modeling of the interaction between a point-focused acoustic lens and a cavity

Placko

Yanagita

Rahani

et al. 2010

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Interaction between a cavity or void in a liquid and a converging ultrasonic beam generated by a point-focused acoustic lens is investigated. A semi-analytical technique called the distributed point source method (DPSM) is adopted because no analytical solution is available for this problem involving cavities of different size and the finite element method is not very efficient for modeling high-frequency ultrasonic problems. The solution shows that if the cavity is placed very close to the focal point of the lens then it can be detected by the acoustic lens. The detectability of the cavity at the off-focus position depends on the distance of the cavity from the focal point. The variation of this distance as the cavity moves in horizontal and vertical directions from the focal point is also investigated.

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Gas Bubble Detection in Fluid Lines by Means of Pulsed Doppler Ultrasound

Cited by 24 publications

References 4 publications

Air Bubbles Pass the Security System of the Dialysis Device Without Alarming

Air Bubbles Pass the Security System of the Dialysis Device Without Alarming

The Sensor in the Venous Chamber Does Not Prevent Passage of Air Bubbles During Hemodialysis

Mesh-free modeling of the interaction between a point-focused acoustic lens and a cavity

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