scholarly journals Lower Body Positive Pressure Application with an Antigravity Suit in Acute Carotid Occlusion

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Karine Berthet ◽  
Anne Claire Lukaszewicz ◽  
Marie-Germaine Bousser ◽  
Didier Payen
Keyword(s):  
Potential Risk ◽  
Venous Pressure ◽  
Carotid Occlusion ◽  
Positive Pressure ◽  
Lower Body ◽  
Lower Body Positive Pressure ◽  
Risk Of Bleeding ◽  
Clinical Recovery ◽  
Pressure Application ◽  
Body Positive

The challenge in acute stroke is still to reperfuse as early as possible the ischemic territory. Since fibrinolytic therapies have a limited window with potential risk of bleeding, having a nonpharmacologic mean to recruit vessels in area surrounding necrosis might be useful. We propose here to use antigravity suit inflated at “venous” pressure levels to shift blood towards thoracic and brain territories. We report two cases of spectacular clinical recovery after acute carotid occlusion.

Hemodynamic responses to graded lower body positive pressure

1993 ◽  
Vol 265 (1) ◽  
pp. H69-H73 ◽  
Author(s):  
X. Shi ◽  
C. G. Crandall ◽  
P. B. Raven
Keyword(s):  
Forearm Blood Flow ◽  
Venous Pressure ◽  
Positive Pressure ◽  
Intramuscular Pressure ◽  
Lower Body ◽  
Central Venous ◽  
Lower Body Positive Pressure ◽  
Pressure Sensitive ◽  
Body Positive ◽  
Forearm Vascular Resistance

Fourteen healthy young men were exposed to progressive increases in lower body positive pressure (LBPP) from 0 to 40 Torr in the supine position. Central venous pressure (CVP) increased 1.09 mmHg (P < 0.05) at 5 Torr LBPP. Between 20 and 40 Torr LBPP CVP increased 0.85 mmHg, resulting in a total increase of 2.06 mmHg (P < 0.05). During 0–20 Torr LBPP mean arterial pressure (MAP) increased from 86 to 89 mmHg with a slope of 0.15 mmHg/Torr LBPP. Stroke volume and cardiac output were significantly increased at 20 Torr LBPP. Beyond 20 Torr LBPP, MAP increased to 95 mmHg at 40 Torr (P < 0.05) with a slope of 0.32 mmHg/Torr LBPP. Forearm blood flow increased above rest at 40 Torr LBPP (P< 0.05). However, neither peripheral nor forearm vascular resistance decreased significantly from rest. Despite the significant increases in MAP, heart rate was unchanged above 20 Torr LBPP. These data suggest that LBPP produces increases in CVP at 0–20 Torr by translocation of blood volume from the legs to the thorax. At LBPP > 20 Torr, further increases in CVP and MAP were produced by other mechanisms possibly related to an activation of intramuscular pressure-sensitive receptors.

Baroreceptor-mediated suppression of osmotically stimulated vasopressin in normal humans

1988 ◽  
Vol 65 (3) ◽  
pp. 1226-1230 ◽  
Author(s):  
S. R. Goldsmith
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Central Venous Pressure ◽  
Venous Pressure ◽  
Positive Pressure ◽  
Lower Body ◽  
Central Venous ◽  
Lower Body Positive Pressure ◽  
Body Positive

Increases in central venous pressure and arterial pressure have been reported to have variable effects on normal arginine vasopressin (AVP) levels in healthy humans. To test the hypothesis that baroreceptor suppression of AVP secretion might be more likely if AVP were subjected to a prior osmotic stimulus, we investigated the response of plasma AVP to increased central venous pressure and mean arterial pressure after hypertonic saline in six normal volunteers. Plasma AVP, serum osmolality, heart rate, central venous pressure, mean arterial pressure, and pulse pressure were assessed before and after a 0.06 ml.kg-1.min-1-infusion of 5% saline give over 90 min and then after 10 min of 30 degrees head-down tilt and 10 min of head-down tilt plus lower-body positive pressure. Hypertonic saline increased plasma AVP. After head-down tilt, which did not change heart rate, pulse pressure, or mean arterial pressure but did increase central venous pressure, plasma AVP fell. Heart rate, pulse pressure, and central venous pressure were unchanged from head-down tilt values during lower-body positive pressure, whereas mean arterial pressure increased. Plasma AVP during lower-body positive pressure was not different from that during tilt. Osmolality increased during the saline infusion but was stable throughout the remainder of the study. These data therefore suggest that an osmotically stimulated plasma AVP level can be suppressed by baroreflex activation. Either the low-pressure cardiopulmonary receptors (subjected to a rise in central venous pressure during head-down tilt) or the sinoaortic baroreceptors (subjected to hydrostatic effects during head-down tilt) could have been responsible for the suppression of AVP.(ABSTRACT TRUNCATED AT 250 WORDS)

Temporary application of lower body positive pressure improves intracranial velocities in symptomatic acute carotid occlusion or tight stenosis: A pilot study

2021 ◽  
pp. 174749302110080
Author(s):  
Isabelle Crassard ◽  
Karine Berthet ◽  
Philippa Lavallée ◽  
Marion Houot ◽  
Didier Payen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Carotid Occlusion ◽  
Positive Pressure ◽  
Lower Body ◽  
Lower Body Positive Pressure ◽  
Body Positive ◽  
Blood Flow Velocities ◽  
Flow Velocities

Background Patients with isolated cervical carotid artery occlusion not eligible to recanalization therapies but with compromised intracranial hemodynamics may be at risk of further clinical events. Apart from lying flat until spontaneous recanalization or adjustment of the collateral circulation hopefully occurs, no specific treatment is currently implemented. Improving collateral flow is an attractive option in this setting. Lower body positive pressure (LBPP) is known to result in rapid venous blood shift from the lower to the upper body part, in turn improving cardiac preload and output, and is routinely used in acute hemorrhagic shock. We report here cerebral blood flow velocities measured during LBPP in this patient population. Methods This is a retrospective analysis of the clinical, physiological, and transcranial Doppler monitoring data collected during and 15 min after LBPP in 21 consecutive patients (10 females, median age: 54 years) with recently symptomatic isolated carotid occlusion/tight stenosis (unilateral in 18) mostly due to atherosclerosis or dissection. LBPP was applied for 90 min at a median 5 days after symptom onset. Results At baseline, middle-cerebral artery velocities were markedly lower on the symptomatic, as compared to asymptomatic, side. LBPP significantly improved blood flow velocities in both the symptomatic and asymptomatic middle-cerebral artery as well as the basilar artery, which persisted 15 min after discontinuing the procedure. LBPP also resulted in mild but significant increases in mean arterial blood pressure. Conclusions LBPP improved intracranial hemodynamics downstream recently symptomatic carotid occlusion/tight stenosis as well as in the contralateral and posterior circulations, which persisted after LBPP deflation. Randomized trials should determine if this easy-to-use, noninvasive, nonpharmacologic approach has long-lasting benefits on the intracranial circulation and improves functional outcome.

Carotid baroreflex responsiveness to lower body positive pressure-induced increases in central venous pressure

1993 ◽  
Vol 265 (3) ◽  
pp. H918-H922 ◽  
Author(s):  
X. Shi ◽  
J. T. Potts ◽  
B. H. Foresman ◽  
P. B. Raven
Keyword(s):  
Central Venous Pressure ◽  
Venous Pressure ◽  
Positive Pressure ◽  
Lower Body ◽  
Central Venous ◽  
Baroreflex Control ◽  
Lower Body Positive Pressure ◽  
Carotid Baroreflex ◽  
Body Positive ◽  
Neck Pressure

Lower body positive pressure (LBPP) was applied at 4 and 30 Torr to increase central venous pressure (CVP). CVP increased with LBPP (r = 0.55, P < 0.01), and the increases were significant at 4 and 30 Torr (7.4 and 7.8 mmHg) from the control (6.0 mmHg). During LBPP cardiac output increased, which was significantly related to the increase in CVP (r = 0.63, P < 0.01). The carotid baroreflex was elicited by trains of neck pressure and suction from 40 to -65 Torr. The carotid-cardiac and carotid-vasomotor baroreflex responses were assessed by determining the maximal gains of heart rate (HR) interval and intraradial mean arterial pressure (MAP) to changes in carotid sinus pressure using a logistic model. The carotid-cardiac and carotid-vasomotor baroreflex gains were negatively related to LBPP, and at 30 Torr, both gains (5.6 ms/mmHg and -0.14 mmHg/mmHg) were significantly smaller than the control (12.4 ms/mmHg and -0.24 mmHg/mmHg). The decreases in carotid-cardiac and carotid-vasomotor baroreflex sensitivity during LBPP were primarily associated with the increases in CVP (r = -0.52, P < 0.01, and r = -0.74, P < 0.01, respectively). These data suggest that the increases in CVP and/or central blood volume diminish the sensitivity of the carotid baroreflex control of HR and MAP by enhancing the tonic inhibitory influence from the cardiopulmonary baroreceptors.

Effect of increased intracardiac and arterial pressure on plasma vasopressin in humans

1984 ◽  
Vol 246 (5) ◽  
pp. H647-H651 ◽  
Author(s):  
S. R. Goldsmith ◽  
A. W. Cowley ◽  
G. S. Francis ◽  
J. N. Cohn
Keyword(s):  
Heart Rate ◽  
Volume Expansion ◽  
Venous Pressure ◽  
Positive Pressure ◽  
Lower Body ◽  
Water Restriction ◽  
Lower Body Positive Pressure ◽  
Arterial Blood ◽  
Body Positive ◽  
Cardiopulmonary Receptors

The effects of loading cardiopulmonary and sinoaortic baroreceptors on plasma arginine vasopressin (AVP) levels were examined in 18 healthy young adults after a mild water restriction. Cardiopulmonary receptors were acutely loaded by volume expansion which increased central venous pressure (CVP) from 4.7 +/- 1.9 to 7.3 +/- 2.2 mmHg but did not change mean arterial blood pressure (MAP). Both receptor groups were acutely loaded by applications of lower body positive pressure, which induced a comparable increase in CVP and, in addition, raised MAP from 85 +/- 6.7 to 93 +/- 6.8 mmHg (P less than 0.001). There was evidence of reflex activation as forearm blood flow and heart rate increased during volume expansion while the increase in heart rate was blocked during lower body positive pressure. Neither intervention significantly altered the control AVP level of 4.6 +/- 1.4 pg/ml. An investigation of more prolonged stimulation of cardiopulmonary receptors was carried out using 1 h of head-down tilt. Again, despite increases in CVP (5.1 +/- 1.3 to 9.0 +/- 1.4 mmHg, P less than 0.005), AVP (5.7 +/- 2.4 pg/ml) did not decrease. MAP did not change during head-down tilt. There were no changes in osmolality throughout any of the studies. AVP levels in humans are therefore not responsive to moderate isosmotic loading of the cardiopulmonary and sinoaortic baroreceptors under conditions of mild water restriction.

scholarly journals Effect of Uphill Running on VO2, Heart Rate and Lactate Accumulation on Lower Body Positive Pressure Treadmills

Sports ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 51
Author(s):  
Daniel Fleckenstein ◽  
Olaf Ueberschär ◽  
Jan C. Wüstenfeld ◽  
Peter Rüdrich ◽  
Bernd Wolfarth
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Body Weight Support ◽  
Positive Pressure ◽  
Lower Body ◽  
Lactate Accumulation ◽  
Biomechanical Stress ◽  
Lower Body Positive Pressure ◽  
Weight Support ◽  
Body Positive

Lower body positive pressure treadmills (LBPPTs) as a strategy to reduce musculoskeletal load are becoming more common as part of sports conditioning, although the requisite physiological parameters are unclear. To elucidate their role, ten well-trained runners (30.2 ± 3.4 years; VO2max: 60.3 ± 4.2 mL kg−1 min−1) ran at 70% of their individual velocity at VO2max (vVO2max) on a LBPPT at 80% body weight support (80% BWSet) and 90% body weight support (90% BWSet), at 0%, 2% and 7% incline. Oxygen consumption (VO2), heart rate (HR) and blood lactate accumulation (LA) were monitored. It was found that an increase in incline led to increased VO2 values of 6.8 ± 0.8 mL kg−1 min−1 (0% vs. 7%, p < 0.001) and 5.4 ± 0.8 mL kg−1 min−1 (2% vs. 7%, p < 0.001). Between 80% BWSet and 90% BWSet, there were VO2 differences of 3.3 ± 0.2 mL kg−1 min−1 (p < 0.001). HR increased with incline by 12 ± 2 bpm (0% vs. 7%, p < 0.05) and 10 ± 2 bpm (2% vs. 7%, p < 0.05). From 80% BWSet to 90% BWSet, HR increases of 6 ± 1 bpm (p < 0.001) were observed. Additionally, LA values showed differences of 0.10 ± 0.02 mmol l−1 between 80% BWSet and 90% BWSet. Those results suggest that on a LBPPT, a 2% incline (at 70% vVO2max) is not yet sufficient to produce significant physiological changes in VO2, HR and LA—as opposed to running on conventional treadmills, where significant changes are measured. However, a 7% incline increases VO2 and HR significantly. Bringing together physiological and biomechanical factors from previous studies into this practical context, it appears that a 7% incline (at 80% BWSet) may be used to keep VO2 and HR load unchanged as compared to unsupported running, while biomechanical stress is substantially reduced.

scholarly journals Analysis of 3-D Kinematics Using H-Gait System during Walking on a Lower Body Positive Pressure Treadmill

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2619
Author(s):  
Yoshiaki Kataoka ◽  
Ryo Takeda ◽  
Shigeru Tadano ◽  
Tomoya Ishida ◽  
Yuki Saito ◽  
...  
Keyword(s):  
Motion Analysis ◽  
Wearable Sensors ◽  
Three Dimensional ◽  
Lower Limbs ◽  
Positive Pressure ◽  
Lower Body ◽  
Lower Body Positive Pressure ◽  
Gait Kinematics ◽  
Peak Knee ◽  
Body Positive

Recently, treadmills equipped with a lower-body positive-pressure (LBPP) device have been developed to provide precise body weight support (BWS) during walking. Since lower limbs are covered in a waist-high chamber of an LBPP treadmill, a conventional motion analysis using an optical method is impossible to evaluate gait kinematics on LBPP. We have developed a wearable-sensor-based three-dimensional motion analysis system, H-Gait. The purpose of the present study was to investigate the effects of BWS by a LBPP treadmill on gait kinematics using an H-Gait system. Twenty-five healthy subjects walked at 2.5 km/h on a LBPP treadmill under the following three conditions: (1) 0%BWS, (2) 25%BWS and (3) 50%BWS conditions. Acceleration and angular velocity from seven wearable sensors were used to analyze lower limb kinematics during walking. BWS significantly decreased peak angles of hip adduction, knee adduction and ankle dorsiflexion. In particular, the peak knee adduction angle at the 50%BWS significantly decreased compared to at the 25%BWS (p = 0.012) or 0%BWS (p < 0.001). The present study showed that H-Gait system can detect the changes in gait kinematics in response to BWS by a LBPP treadmill and provided a useful clinical application of the H-Gait system to walking exercises.

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