In vivo Detection of Circulating Gas Emboli associated with Decompression Sickness using the Doppler Flowmeter

Gillis, Murlin F.; Peterson, P.L.; Karagianes, M.T.

doi:10.1038/217965a0

Cited by 48 publications

(17 citation statements)

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“…This phenomenon was first exploited by Gillis and coworkers 4 for the in vivo detection of circulating gas emboli during decompression sickness in animals and later to detect air embolism during neurosurgical procedures and cardiopulmonary bypass using the transcranial Doppler Technique. 8 -9 Transcranial Doppler study may not be possible when the transcranial ultrasonic window or the middle cerebral artery signal cannot be located.…”

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confidence: 99%

Detection of paradoxical cerebral echo contrast embolization by transcranial Doppler ultrasound.

Teague

Sharma

1991

Stroke

127

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Contrast echocardiography has been shown to be a sensitive method for detecting patent foramen ovale in embolic stroke, implying paradoxical embolization. However, not all twodimensional echocardiographic studies are of diagnostic quality, and direct evidence for paradoxical cerebral embolization remains lacking. We addressed these problems by simultaneously using transcranial Doppler ultrasound and contrast echocardiography to compare relative sensitivity and concordance in the detection of right-to-left vascular shunting. Forty-six patients with stroke, transient neurologic defect, or question of atrial septal defect underwent study at rest and during Valsalva strain. Two-dimensional echocardiography detected shunting in 26% at rest and 15% during Valsalva strain, whereas transcranial Doppler study returned rates of 41% and 41%, respectively. Concordance was 82% and 75%, respectively. Discordant studies almost always had evidence of paradoxical contrast embolization by transcranial T he etiology of stroke in more than a third of young adult patients may remain uncertain even after extensive clinical study. 1 Paradoxical embolization via patent atrial foramen ovale has become suspect as a cause of embolic strokes or transient ischemic attacks. "3 Contrast echocardiography with patients at rest and during provocative maneuvers has been shown to be a sensitive method for noninvasively detecting patent foramen ovale in these patients.1 -3 However, not all two-dimensional echocardiographic studies are of diagnostic quality. Moreover, the technique only reveals the substrate for paradoxical embolization; the arterial delivery of emboli originating in the venous system at critical target organs is not demonstrated.The objective of contrast echocardiography in the evaluation of interatrial shunting is the detection of microcavitation gas bubbles entering left heart chambers after intravenous injection. As an alternative to ultrasonic imaging, Doppler ultrasound has served as a sensitive detector of blood-borne gas bubbles in From the University of Oklahoma Health Sciences Center, Cardiology Section, Oklahoma City, Okla.Presented in part at the 61st Scientific Sessions of the American Heart Association.Address for correspondence: Steve M. Teague, MD, MetroHealth Medical Center, 3395 Scranton Road, Cleveland, OH 44109.Received August 14, 1990; accepted February 21, 1991. decompression sickness by demonstrating air bubbles in the pulmonary artery. 4 -7 Specially designed transcranial Doppler devices have been used to detect micro air emboli in the middle cerebral artery during surgery. -9The purpose of this study was to use transcranial Doppler ultrasound as a detector of gas bubbles in the middle cerebral artery simultaneously with two-dimensional apical echocardiography as a detector of bubbles in the left atrium and ventricle so as to compare relative sensitivity and demonstrate concordance in the detection of right-to-left vascular shunting. Subjects and MethodsWe studied 46 consecutive patients referred for contr...

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confidence: 99%

Detection of paradoxical cerebral echo contrast embolization by transcranial Doppler ultrasound.

Teague

Sharma

1991

Stroke

127

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“…D'abord détectés chez les plongeurs lors des accidents de décompression (à la fin des années 1960) [5], ces signaux ont ensuite été identifiés dans diverses circonstances [1,2,6-8], et rattachés à des micro-emboles solides (cruoriques) ou gazeux [9,10]. Les critères consensuels permettant leur reconnaissance sont les suivants [4] :…”

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Visualisation du passage de micro-emboles cérébraux par ultrasonographie en mode B-Flow

Aichoun¹,

Schuster²,

Rienzo³

et al. 2015

Journal des Maladies Vasculaires

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“…However, current technology does not allow differentiation between say a larger platelet embolus and a smaller thrombus embolus. The use of models has allowed the detailed study of the frequency spectrum associated with emboli and artefact, and com puterised algorithms have been developed which can differentiate between the two.In the 1960s the extreme sensitivity of the ultrasonic Doppler flowmeter to air bubbles in the circulating fluid had been noted regularly during in vitro testing and cali bration procedures [1]. This led to its exploitation in the deliberate detection of gaseous emboli.…”

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confidence: 99%

“…Every air bubble introduced, 'no mat ter how small', was detected. In subsequent studies using Doppler flowmeters, gaseous emboli appeared as a tran sient increase in audio signal amplitude with a character istic sound best described as a 'chirp' [1], Recent technol ogy allows the Doppler signal to be processed by fast Fou rier transformation and the frequency spectrum to be dis played; air emboli appears as high intensity signals within the flow velocity spectrum.…”

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Experimental Embolic Events

Markus¹

1995

Cerebrovasc Dis

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In both in vitro and in vivo models, microscopic air bubbles and glass microspheres as small as 5–20 µm, can be detected using Doppler ultrasound and appear as short duration high intensity signals. Less echogenic common embolic materials, such as thrombus, atheroma and platelet aggregates, can also be detected with a high sensitivity, although the smallest emboli which have been introduced into models are 0.2–0.4 mm. Emboli of all types result in a characteristic frequency-focused short duration high intensity signal, although very intense signals may result in receiver overload and aliasing. Both in vitro and in animal models, a positive correlation has been found between embolus size and both relative intensity increase and duration of embolic signals. This may allow information about embolus relative size to be derived from the Doppler signal. Air bubbles result in more intense signals than similarly sized solid emboli, and thrombus and atheroma embolic signals are more intense than those produced by platelet aggregates. However, current technology does not allow differentiation between say a larger platelet embolus and a smaller thrombus embolus. The use of models has allowed the detailed study of the frequency spectrum associated with emboli and artefact, and computerised algorithms have been developed which can differentiate between the two.

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In vivo Detection of Circulating Gas Emboli associated with Decompression Sickness using the Doppler Flowmeter

Cited by 48 publications

References 1 publication

Detection of paradoxical cerebral echo contrast embolization by transcranial Doppler ultrasound.

Detection of paradoxical cerebral echo contrast embolization by transcranial Doppler ultrasound.

Visualisation du passage de micro-emboles cérébraux par ultrasonographie en mode B-Flow

Experimental Embolic Events

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