Assessment of pulse transit time to indicate cardiovascular changes during obstetric spinal anaesthesia

Sharwood-Smith, Geoffrey H.; Bruce, John; Drummond, Gordon B.

doi:10.1093/bja/aei266

Cited by 82 publications

(72 citation statements)

References 26 publications

(23 reference statements)

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“…36 More recently, oximeter-based PTT has been used to obtain accurate measurements of changes in blood pressure that occur during induction of general anesthesia as well as to achieve rapid detection of the onset of hypotension in patients undergoing spinal anesthesia for Cesarean delivery. 37,38 While more validation studies are needed, the near instantaneous response time shown in both of these studies is encouraging. 33,34 In aggregate, these data suggest that PTT, at least over short time periods, provides useful information for immediate detection of hemodynamic changes that might be missed if only an oscillometric cuff method is used for periodic blood pressure assessments.…”

Section: Physiology Of the Ppgmentioning

confidence: 84%

Advances in photoplethysmography: beyond arterial oxygen saturation

Bartels

Thiele

2015

Can J Anesth/J Can Anesth

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Purpose Photoplethysmography permits continuous measurement of heart rate and peripheral oxygen saturation and has been widely used to inform clinical decisions. Recently, a myriad of noninvasive hemodynamic monitoring devices using this same technology have been increasingly available. This narrative review aims to summarize the principles that form the basis for the function of these devices as well as to comment on trials evaluating their accuracy and clinical application. Principal findings Advanced monitoring devices extend photoplethysmography technology beyond measuring oxygen concentration and heart rate. Quantification of respiratory variation of the photoplethysmographic waveform reflects respiratory variation of the arterial pressure waveform and can be used to gauge volume responsiveness. Both the volume-clamp and physiocal techniques are extensions of conventional photoplethysmography and permit continuous measurement of finger arterial blood pressure. Finger arterial pressure waveforms can subsequently inform estimations of cardiac output. Conclusions Although respiratory variations of the plethysmographic waveform correlate only modestly with the arterial blood pressure waveform, fluid responsiveness can be relatively consistently assessed using both approaches. Continuous blood pressure measurements obtained using the volume-clamp technique may be as accurate as conventional brachial noninvasive blood pressure measurements. Most importantly, clinical comparative effectiveness studies are still needed in order to determine if these technologies can be translated into improvement of relevant patient outcomes. RésuméObjectif La photopléthysmographie permet la mesure continue de la fréquence cardiaque et de la saturation en oxygène périphérique, et elle est largement utilisée pour les prises de décisions cliniques. Depuis peu, un très grand nombre de dispositifs non invasifs de surveillance hémodynamique utilisant la même technologie envahit le marché. Cette synthèse narrative vise à résumer les principes à la base du fonctionnement de ces dispositifs et à commenter les essais évaluant leur exactitude ainsi que leurs applications cliniques. Constatations principales Les dispositifs de surveillance avancée étendent la technologie de photopléthysmographie au-delà de la mesure de la concentration en oxygène et de la fréquence cardiaque. La quantification de la variation respiratoire du tracé photopléthysmographique reflète la variation respiratoire du tracé de pression artérielle et peut servir à jauger la réactivité au volume. Les deux techniques de compression volumique (volume-clamp) au doigt et la technique physiocal sont des prolongements de Author contributions Karsten Bartels wrote approximately 50% of the manuscript and critically edited the remainder. Robert H. Thiele wrote approximately 50% of the manuscript and critically edited the remainder.

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Section: Physiology Of the Ppgmentioning

confidence: 84%

Advances in photoplethysmography: beyond arterial oxygen saturation

Bartels

Thiele

2015

Can J Anesth/J Can Anesth

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“…This may constitute a problem in certain situations such as when flow redistribution to central parts of the body (heavy injury, temperature etc.) degrades these measurements; another situation where central measurements may prove advantageous is during the presence of strong movements of the peripheral locations which affect pressure measurements [4].…”

Section: Introductionmentioning

confidence: 99%

“…1) Method 1: Sugawara et al [6] showed a linear relationship between percentage changes in instantaneous blood pressure and diameter of the carotid artery. Method 2: According to [3,4,7] there is a non-linear relationship between mean arterial blood pressure ( P) and compliance (ratio of change in volume for a change in pressure), which in turn is related to pulse wave velocity (PWV).…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation into radar‐based central blood pressure estimation

Solberg¹,

Aardal

Berger

et al. 2015

IET Radar, Sonar & Navigation

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To assess whether radar technology can be used for monitoring blood pressure via information from the aorta, two experiments were performed: (i) measurements on a phantom model and (ii) acquisitions on a human subject for in vivo experiments. A linear dependency of phase on radius in the radar echoes in the phantom model showed that the information regarding the radius of a circular, cylindrical object depended on the clutter environment: in a low-clutter case two distinct reflections were identified, whereas in the high-clutter case it was possible to extract a proxy. Radar echoes from antennas strapped to the back of a human subject showed a clear signature from a discernible, distinct reflector believed to be the aorta. However, as for the highclutter case, only a proxy for aortic radius is available as basis for estimation, which is most likely coupled with aortic displacements.

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“…1 However, there is limited understanding in the current literature about the potential use of PTT-related measurement in assessing the ratio of the crural and brachial BP or the ankle brachial index (ABI).…”

mentioning

confidence: 99%