Cardiovascular Function and Arterial Blood Gases during Isolated Ultrafiltration in Healthy Man

Abstract

In order to recognize possible cardiovascular signs of underhydration during isolated ultrafiltration (IUF), we have studied the physiological hemodynamic adaptation to IUF in healthy man both above and below normohydration. In 7 subjects IUF was performed with the subjects in a normohydrated state at the start of IUF. In 8 subjects the IUF was preceded by a 1-hour infusion of Ringer solution equal to 3% of body weight. By invasive techniques, cardiac index (thermodilution), stroke index, heart rate, brachial and pulmonary arterial blood pressures, systemic vascular resistance index, central blood temperature, P_aO₂ and P_aCO₂ were measured. Calf vascular resistance was assessed by venous occlusion plethysmography. A recirculation period of 30 min was followed by IUF in both study groups. During IUF with overhydration and normohydration at the start of IUF, cardiac output fell because of a decline in stroke volume and an unchanged heart rate. Blood pressure remained constant because of systemic vascular constriction. P_aO₂ and P_aCO₂ remained unchanged. IUF in healthy man is mainly characterized by vascular constriction and an unchanged heart rate. Thus, the cardiovascular adaptation to ultrafiltration was the same whether or not ultrafiltration was performed at overhydration or normohydration at the start of ultrafiltration. Therefore, it is unlikely that monitoring of heart rate or noninvasive recording of blood pressure can predict whether a subject is becoming underhydrated during isolated ultrafiltration. The adaptation to IUF is similar to that observed during the treatment of uremic patients without complications.

Cardiovascular Function and Arterial Blood Gases during Sham Dialysis in Healthy Man

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Intercenter variance in clinical trials of head trauma—experience of the National Acute Brain Injury Study: Hypothermia

“…16 Dehydration produces vasoconstriction in some physiological states, and the incidence of dehydration differed among centers. 8,9 The lack of a standard method for the management of fluids, morphine, and vasopressor therapy probably led to the variations in MABP and CPP management.…”

Die Rolle von Hämodynamik und Biosignalen für eine „verträgliche“ Hämodialyse

“…In einer visionären experimentellen Arbeit von 1988 konnte die Bergström-Gruppe zeigen, dass bei isolierter UF bei Gesunden ein klinisch apparenter Bezold-Jarisch-Reflex durch eine physiologische, sympathotone Gegenregulation mit Vasokonstriktion verhindert wird [60]. Somit kann hier die Brücke geschlagen werden von den osmotischen Dialyseverschiebungen zum Status des vegetativen Nerven systems, welches unter unseren heutigen Dialysebedingungen vermutlich zu wenig adressiert wird.…”