Arterial pressure variations as parameters of brain perfusion in response to central blood volume depletion and repletion

Bronzwaer, Anne-Sophie G. T.; Stok, Wim J.; Westerhof, Berend E.; Lieshout, Johannes J. van

doi:10.3389/fphys.2014.00157

Cited by 13 publications

(13 citation statements)

References 64 publications

(75 reference statements)

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“…Measurements were performed with subjects positioned on a custom built computer controlled tilt table which minimizes confounding muscle tensing and vestibular stimulation [ 19 ]. In healthy humans the horizontal position provides for an 'optimal' central blood volume [ 20 , 21 ] and therefore resting supine measurements represent normovolemic conditions whereas 30° (gravitational load 0.5 G) and 70° (0.9 G) passive head-up tilt (HUT) induces central hypovolemia [ 22 , 23 ]. Following stepwise elevation of body angle, that body position was maintained for 5 minutes at respectively 30° and 70° to allow for hemodynamic adaptation.…”

Section: Methodsmentioning

confidence: 99%

Arterial Pressure Variation as a Biomarker of Preload Dependency in Spontaneously Breathing Subjects – A Proof of Principle

et al. 2015

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ObjectivePulse (PPV) and systolic pressure variation (SPV) quantify variations in arterial pressure related to heart-lung interactions and have been introduced as biomarkers of preload dependency to guide fluid treatment in mechanically ventilated patients. However, respiratory intra-thoracic pressure changes during spontaneous breathing are considered too small to affect preload and stroke volume sufficiently for the detection by PPV and/or SPV. This study addressed the effects of paced breathing and/or an external respiratory resistance on PPV and SPV in detecting preload dependency in spontaneously breathing subjects.MethodsIn 10 healthy subjects, hemodynamic and respiratory parameters were evaluated during progressive central hypovolemia (head-up tilt). Breathing conditions were varied by manipulating breathing frequency and respiratory resistance. Subjects responding with a reduction in stroke volume index ≥15% were classified as having developed preload dependency. The ability for PPV and SPV to predict preload dependency was expressed by the area under the ROC curve (AUC).ResultsA breathing frequency at 6/min increased the PPV (16±5% vs. 10±3%, p<0.001) and SPV (9±3% vs. 5±2%, p<0.001) which was further enhanced by an expiratory resistance (PPV: 19±3%, p = 0.025 and SPV: 10±2%, p = 0.047). These respiratory modifications, compared to free breathing, enhanced the predictive value of PPV with higher accuracy (AUC: 0.92 vs. 0.46).ConclusionUnder conditions of progressive central hypovolemia, the application of an external respiratory resistance at a breathing frequency of 6/min enhanced PPV and SPV and is worth further study for detection of preload dependency from arterial pressure variations in non-ventilated subjects.

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Section: Methodsmentioning

confidence: 99%

Arterial Pressure Variation as a Biomarker of Preload Dependency in Spontaneously Breathing Subjects – A Proof of Principle

et al. 2015

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“…Positional changes from supine to sitting or standing result in a decrease of cerebral blood flow (CBF) as demonstrated by different techniques ( Yoshimoto et al, 1994 , Ouchi et al, 2001 , Oblak et al, 2002 , Alperin et al, 2005 , Wang et al, 2010 , Bronzwaer et al, 2014 ). CBF measurements by extracranial Doppler echography of the internal carotid and vertebral arteries (ICA and VA) in the supine position have been described in a number of studies ( Schoning et al, 1994 , Deane and Markus, 1997 , Seidel et al, 1999 , Dorfler et al, 2000 , Scheel et al, 2000 , Yazici et al, 2005 , Oktar et al, 2006 , Albayrak et al, 2007 , Nemati et al, 2009 , Nevo et al, 2010 , Sato et al, 2012 , Liu et al, 2013 ).…”

Section: Introductionmentioning

confidence: 99%

Cerebral blood flow changes during tilt table testing in healthy volunteers, as assessed by Doppler imaging of the carotid and vertebral arteries

Campen¹,

Verheugt

Visser³

2018

Clinical Neurophysiology Practice

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“…The tilt angle plotted in time describes a sine between 0°and 60°at the given frequencies. A version of the SinTilt-protocol has been used in an earlier publication from this laboratory (Bronzwaer et al 2014).…”

Section: Methodsmentioning

confidence: 99%

Slow sinusoidal tilt movements demonstrate the contribution to orthostatic tolerance of cerebrospinal fluid movement to and from the spinal dural space

et al. 2019

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Standing up elicits a host of cardiovascular changes which all affect the cerebral circulation. Lowered mean arterial blood pressure ( ABP ) at brain level, change in the cerebral venous outflow path, lowered end‐tidal P CO 2 ( P ET CO 2 ), and intracranial pressure ( ICP ) modify cerebral blood flow ( CBF ). The question we undertook to answer is whether gravity‐induced blood pressure ( BP ) changes are compensated in CBF with the same dynamics as are spontaneous or induced ABP changes in a stable position. Twenty‐two healthy subjects (18/4 m/f, 40 ± 8 years) were subjected to 30° and 70° head‐up tilt ( HUT ) and sinusoidal tilts (SinTilt, 0°↨60° around 30° at 2.5–10 tilts/min). Additionally, at those three tilt levels, they performed paced breathing at 6–15 breaths/min to induce larger than spontaneous cardiovascular oscillations. We measured continuous finger BP and cerebral blood flow velocity ( CBF v) in the middle cerebral artery by transcranial Doppler to compute transfer functions ( TF s) from ABP ‐ to CBF v oscillations. SinTilt induces the largest ABP oscillations at brain level with CBF v gains strikingly lower than for paced breathing or spontaneous variations. This would imply better autoregulation for dynamic gravitational changes. We demonstrate in a mathematical model that this difference is explained by ICP changes due to movement of cerebrospinal fluid ( CSF ) into and out of the spinal dural sack. Dynamic cerebrovascular autoregulation seems insensitive to how BP oscillations originate if the effect of ICP is factored in. CSF ‐movement in‐and‐out of the spinal dural space contributes importantly to orthostatic tolerance by its effect on cerebral perfusion pressure.

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Arterial pressure variations as parameters of brain perfusion in response to central blood volume depletion and repletion

Cited by 13 publications

References 64 publications

Arterial Pressure Variation as a Biomarker of Preload Dependency in Spontaneously Breathing Subjects – A Proof of Principle

Arterial Pressure Variation as a Biomarker of Preload Dependency in Spontaneously Breathing Subjects – A Proof of Principle

Cerebral blood flow changes during tilt table testing in healthy volunteers, as assessed by Doppler imaging of the carotid and vertebral arteries

Slow sinusoidal tilt movements demonstrate the contribution to orthostatic tolerance of cerebrospinal fluid movement to and from the spinal dural space

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