Postural Pseudoanemia: Posture-Dependent Change in Hematocrit

Jacob, Giris; Raj, Satish R.; Ketch, Terry; Pavlin, Boris I; Biaggioni, Italo; Ertl, Andrew C.; Robertson, David

doi:10.4065/80.5.611

Cited by 53 publications

(50 citation statements)

References 17 publications

(16 reference statements)

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“…3). The lower hematocrit of the supine posture occasionally puts otherwise healthy persons into the usually accepted ''anemia'' range of hematocrit, and has therefore been called ''postural pseudoanemia [9]'' for that reason. Thus, much of the ''noise'' in hematocrit measurement in clinical practice is actually not noise but reflective of changes in blood related to patient's posture in the time leading up to the sampling.…”

Section: Orthostatic Blood Volume Shiftmentioning

confidence: 99%

The pathophysiology and diagnosis of orthostatic hypotension

Robertson

2008

Clin Auton Res

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139

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Orthostatic Hypotension (OH) is a common manifestation of blood pressure dysregulation. OH takes a heavy toll on quality of life. It has many potential etiologies, and many effects of aging can increase susceptibility to OH. Neurological disorders are especially likely to cause severe OH. In this brief review, the pathogenesis of OH is considered, particularly in terms of autonomic neuropathy, multiple system atrophy (MSA), pure autonomic failure, baroreflex failure, and dopamine beta hydroxylase deficiency. While OH is difficult to treat, its control greatly enhances the quality of life.

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Section: Orthostatic Blood Volume Shiftmentioning

confidence: 99%

The pathophysiology and diagnosis of orthostatic hypotension

Robertson

2008

Clin Auton Res

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139

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“…Dynamic ⌬PV (%)ϭ100ϫ(Hct 1 ϪHct 2 )/Hct 2 ϫ(1ϪHct 1 ). 11 Percentage of change in the total plasma protein (triplicates measured with Refractometer, Leica) was calculated to further confirm the PV% changes in Hct.…”

Section: Plasma Shiftmentioning

confidence: 99%

“…8,9 As a result, Ն12% of intravascular fluid transfers from the intravascular space to surrounding tissues. 10,11 This plasma shift can be estimated indirectly by measuring sequential changes in hematocrit (Hct) or total protein (TP) concentration. 10,12 Although much has been reported about the hemoconcentration effect on total plasma protein level, no data are available regarding this effect on a variety of specific circulating proteins, including coagulation factors.…”

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confidence: 99%

Orthostatic Hypercoagulability

et al. 2008

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Abstract-Orthostatic stress causes significant plasma shift and raises transmural pressure in lower extremities, resulting in an increase in endothelial activation and plasma proteins concentrations, possibly including coagulation factors. This may lead to activation of the coagulation system during standing. To test this hypothesis, we recruited 18 healthy volunteers (9 females and 9 males; mean age: 25Ϯ1.2 years; body mass index: 21.7Ϯ0.5 kg/m 2 ). Hemodynamics, plasma shift (extrapolated from sequential hematocrit concentration), plasma proteins, and coagulation tests, including procoagulants; fibrinogen, factor V, and factor VIII activity; prothrombin fragments 1 and 2; and endothelial activation-related factors (tissue factor and von Willebrand factor), as well as protein C global pathway, were determined at rest supine and at 15 minutes, 30 minutes, and 60 minutes of still standing. Thirty minutes of standing caused a decrease in plasma volume by 12.0Ϯ0.5% and an increase in plasma protein by 13.0Ϯ0.7%. Fibrinogen, factor V, and factor VIII activity rose by 12.0Ϯ1.2%, 13.0Ϯ1.0%, and 40.0Ϯ6.0% (PϽ0.002 for all), respectively. Prothrombin fragments 1 and 2 were elevated by 150.0Ϯ30.0%. Tissue factor and von Willebrand factor increased by 30.0Ϯ9.0% and 17.4Ϯ51.0% (PϽ0.02 for both), respectively. However, protein C assay results decreased from 0.95Ϯ0.20 to 0.83Ϯ0.16 (PϽ0.001). We hereby introduce a novel physiological mechanism, "orthostatic procoagulation," that should be considered during coagulation tests. Furthermore, it could be extrapolated to the pathophysiology of stasis and venous thromboembolism.

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“…Youmans et al [5] estimated that the incidence of this alteration ranged from 6% to 15% in healthy subjects. More recently, Jacob et al [6] referred to the condition observed after hospital admission in patients who undergo phlebotomy in a supine position as "postural pseudo-anemia." In their experimental study on 28 healthy subjects, the authors found that the average hematocrit was 41.8% when samples were taken from the patient in an upright position against 37.7% in a supine position [6,7].…”

Section: Introductionmentioning

confidence: 98%

“…More recently, Jacob et al [6] referred to the condition observed after hospital admission in patients who undergo phlebotomy in a supine position as "postural pseudo-anemia." In their experimental study on 28 healthy subjects, the authors found that the average hematocrit was 41.8% when samples were taken from the patient in an upright position against 37.7% in a supine position [6,7]. Rapid changes in white blood cell (WBC) count, with an increase in leukocytes, mainly neutrophils, can be caused by inflammatory diseases and psychologic stress from pain, anxiety, or trauma.…”

Section: Introductionmentioning

confidence: 98%