Beat-to-beat measurement of cardiovascular effects of a single subcutaneous dose of terbutaline in healthy subjects

Objective: To evaluate the cardiovascular effects over time of a single subcutaneous (SC) dose of terbutaline 0.75mg in young healthy volunteers using continuous, beat-to-beat monitoring of cardiovascular effects. Design and methods: Nine healthy young volunteers were administered a SC dose of terbutaline sulphate 0.75mg. Cardiovascular effects...

A comparison of cardiac output derived from the arterial pressure wave against thermodilution in cardiac surgery patients

In three clinical centres, we compared a new method for measuring cardiac output with conventional thermodilution. The new method computes beat-to-beat cardiac output from radial artery pressure by simulating a three-element model of aortic input impedance, and includes non-linear aortic mechanical properties and a self-adapting systemic...

Why use Finapres or Portapres rather than intra-arterial or intermittent non-invasive techniques of blood pressure measurement?

In the clinic, blood pressure is measured almost exclusively using non- invasive intermittent techniques, of which the auscultatory (Riva- Rocci/Korotkoff, RRK) and the computerized oscillometric method are most often used. However, both methods only provide a momentary value. In addition, the accuracy is hampered by phenomena such as cuff...

Single injection thermodilution: A flow-corrected method

Application of the Stewart-Hamilton equation in the thermodilution technique requires flow to be constant. In patients in whom ventilation of the lungs is controlled, flow modulations may occur leading to large errors in the estimation of mean cardiac output. Methods: To eliminate these errors, a modified equation was developed. The resulting...

Computation of aortic flow from pressure in humans using a nonlinear, three-element model

We computed aortic flow pulsations from arterial pressure by simulating a nonlinear, time-varying three-element model of aortic input impedance. The model elements represent aortic characteristic impedance, arterial compliance, and systemic vascular resistance. Parameter values for the first two elements were computed from a published, age...

Cardiovascular instability and baroreflex activity in a patient with tetanus

In a patient with tetanus we tested the hypothesis that the hyperadrenergic cardiovascular instability might be due to impairment of the baroreceptor reflex by the tetanus toxin. Baroreflex sensitivity assessed with the phenylephrine method was found to be normal. Changes in arterial pressure correlated inversely with relative changes in plasma...

Non-invasive continuous finger blood pressure measurement during orthostatic stress compared to intra-arterial pressure

The aim of the study was to evaluate whether invasive blood pressure responses to orthostatic stress can be replaced by non-invasive continuous finger blood pressure responses. Intrabrachial and Finapres blood pressures were simultaneously measured during passive head up tilt and during active standing from the supine or sitting position in...

An adequate strategy for the thermodilution technique in patients during mechanical ventilation

The application of the thermodilution method in conditions associated with variations in blood flow implies a misuse of the Stewart Hamilton equation. Therefore, we studied the reliability of the thermodilution method for the estimation of mean cardiac output (CO) during mechanical ventilation in patients (n = 9). Variation of the injection...

Continuous cardiac output monitoring by pulse contour during cardiac surgery

Most pulse contour methods are unreliable under changing haemodynamic conditions, because no corrections are made for pressure-dependent compliance and reflections of pressure waves. The pulse contour method of Wesseling includes such corrections. Four thermodilution measurements equally spread over the ventilatory cycle were used to calibrate...