Continuous Cardiac Output in Septic Shock by Simulating a Model of the Aortic Input Impedance

Jellema, Wilbert T.; Wesseling, Karel H.; Groeneveld, A. B. Johan; Stoutenbeek, C. P.; Thijs, L. G.; Lieshout, Johannes J. van

doi:10.1097/00000542-199905000-00016

Cited by 194 publications

(159 citation statements)

References 31 publications

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“…The ModelFlow method assumes a population average of aortic area depending on sex, age, height and mass. Several studies have validated the ModelFlow method compared with the standard invasive techniques (thermodilution and pulse dye densitometry) and indicate that this method provides a reliable estimate of changes in cardiac output in healthy exercising humans (Matsukawa et al 2004), patients with septic shock (Jellema et al 1999) or during prolonged tilt testing (Harms et al 1999). However, the validity of absolute ModelFlow estimates are uncertain during initial changes in posture or with ageing (Remmen et al 2002).…”

Section: Limitationsmentioning

confidence: 99%

Compression leggings modestly affect cardiovascular but not cerebrovascular responses to heat and orthostatic stress in young and older adults

Lucas

Ainslie

Morrison

et al. 2011

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We tested the hypothesis that wearing commercially available compression leggings would attenuate postural reductions in mean arterial blood pressure (MAP) and cerebral perfusion during heat stress, particularly in older adults. Six older (70 years±4) and six younger (29 years±4) males were heated (esophageal temperature raised 0.5°C) in a water-perfused suit whilst wearing compression or control leggings (>1 week apart, randomized order). Blood flow velocity in the middle cerebral artery (MCAv), blood pressure (photoplethysmography), total peripheral resistance (TPR; ModelFlow) and the partial pressure of end-tidal carbon dioxide were measured continuously before and during 3-min standing in each thermal state. When supine, compression leggings did not change any cardiorespiratory variables in either age group or thermal condition (P>0.05). Upon standing, wearing compression leggings delayed (~15%; P=0.044) the maximal drop (nadir) in MAP irrespective of age or thermal condition. During the last minute of standing, wearing compression leggings in normothermia increased TPR (+16%) in older participants but dropped TPR (−8%) in younger participants (P=0.004 compression×age group). When standing and heated, wearing compression leggings lowered TPR in older and younger participants (~43%; P<0.01) without changing MAP or MCAv (P>0.05). In older adults, when standing, compression leggings maintained MAP by elevating TPR. In contrast, under combined heat and orthostatic stress, wearing compression leggings dropped TPR in both older and younger adults, though MAP and MCAv were maintained.

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Section: Limitationsmentioning

confidence: 99%

Compression leggings modestly affect cardiovascular but not cerebrovascular responses to heat and orthostatic stress in young and older adults

Lucas

Ainslie

Morrison

et al. 2011

AGE

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“…When calibrated against a "gold standard" method to determine cardiac output (CO) such as thermodilution or the Fick method, this methodology provides accurate estimates of changes in SV in patients with septic shock 20 and cardiovascular disease 19,21 and during orthostatic stress. 22 The middle cerebral artery blood velocity (MCA V) was measured in the proximal segment of the right MCA (Multidop X4).…”

Section: Measurementsmentioning

confidence: 99%

Impaired Cerebral Autoregulation in Patients With Malignant Hypertension

et al. 2004

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Background-In patients with a malignant hypertension, immediate parenteral treatment with blood pressure-lowering agents such as intravenous sodium nitroprusside (SNP) is indicated. In this study, we evaluated static and dynamic cerebral autoregulation (CA) during acute blood pressure lowering with SNP in these patients. Methods and Results-In 8 patients with mean arterial pressure (MAP) Ͼ140 mm Hg and grade III or IV hypertensive retinopathy at hospital admission, middle cerebral artery blood velocity (MCA V) and blood pressure were monitored. Dynamic CA was expressed as the 0.1-Hz MCA V mean to MAP phase lead and static CA as the MCA V mean to MAP relationship during SNP treatment. Eight normotensive subjects served as a reference group. In the patients, the MCA V mean to MAP phase lead was lower (30Ϯ8°versus 58Ϯ5°, meanϮSEM; PϽ0.05), whereas the transfer gain tended to be higher. During SNP treatment, target MAP was reached within 90 minutes in all patients. The MCA V mean decrease was 22Ϯ4%, along with a 27Ϯ3% reduction in MAP (from 166Ϯ4 to 121Ϯ6 mm Hg; PϽ0.05) in a linear fashion (averaged slope, 0.82Ϯ0.15% cm · s Ϫ1 · % mm Hg

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“…40 The Modelflow method assumes a population average of aortic area depending on gender, age, height and weight. Several studies have validated the Modelflow method compared with standard invasive techniques and indicate that this method provides a reliable estimate of changes in cardiac output in a variety of physiological 41 and pathological 42,43 conditions. Moreover, it has been shown that after calibration, the tracking of changes in SV and .…”

Section: Methodological Considerationsmentioning

confidence: 99%

Identical pattern of cerebral hypoperfusion during different types of syncope

et al. 2009

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Syncope is caused by insufficient oxygen supply to the brain. There have been attempts to classify syncope on the basis of defects in the venous system, arterial system (that is impaired systemic vascular resistance) or a combination of the two (that is mixed). We examined the hypothesis that a comparable decrease in cerebral perfusion would be evident at pre-syncope irrespective of the category of dysfunction. Young healthy volunteers (N ¼ 37) participated. The protocol consisted of 15 min supine rest, followed by 601 head-up tilt and lower body suction in increments of À10 mm Hg for 5 min each until pre-syncope. Beat-to-beat blood pressure (BP) (Finometer or intra-arterial), cardiac output (Finometer), middle cerebral artery blood velocity (MCAv), end-tidal CO 2 and cerebral oxygenation were monitored continuously. At pre-syncope, mixed dysfunction was common (21 out of 37 participants), followed by venular dysfunction (15 out of 37 participants). In the venular and mixed groups, comparable orthostatic tolerance and declines in BP (À37 vs À43% from baseline, respectively), end-tidal PCO 2 , MCAv (À35 vs À38%) and cerebral oxygenation (À5 vs À7%) were evident despite distinct mechanisms purportedly being responsible for the hypotension. Although different determinants of hypotension do exist, cerebral hypoperfusion occurs to a similar extent.

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Continuous Cardiac Output in Septic Shock by Simulating a Model of the Aortic Input Impedance

Cited by 194 publications

References 31 publications

Compression leggings modestly affect cardiovascular but not cerebrovascular responses to heat and orthostatic stress in young and older adults

Compression leggings modestly affect cardiovascular but not cerebrovascular responses to heat and orthostatic stress in young and older adults

Impaired Cerebral Autoregulation in Patients With Malignant Hypertension

Identical pattern of cerebral hypoperfusion during different types of syncope

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