A comparison of bolus versus continuous cardiac output in an experimental model of heart failure

Non-invasive assessment of cardiac hemodynamics in patients with advanced cancer and with chronic heart failure: a pilot feasibility study

INTRODUCTION

Relationships between cardiac pressure and volume have been suggested as markers of cardiac contractility; parameters include stroke work and the maximal rate of pressure rise during isovolumic contraction (dP/dtmax). Patients with cancer often display dyspnea and fatigue. These are also frequent symptoms in patients with chronic heart failure (HF). The reasons for similar symptoms in cancer patients are unknown. Using the novel Nexfin Finapres technique, we sought to assess measures of cardiac performance in patients with cancer and compare these values with those from control subjects and patients with chronic HF.

MATERIAL AND METHODS

We prospectively studied 98 patients (control n = 18, chronic HF n = 37, advanced pancreatic or colorectal cancer n = 43) and assessed blood pressure (BP), stroke volume (SV), cardiac output (CO), and dP/dtmax at rest.

RESULTS

All parameters of interest could be assessed using the Nexfin Finapres technique with SV and CO being significantly higher in patients with cancer than in controls (both p < 0.05). The SV was significantly higher in patients with chronic HF than in controls (p < 0.05). In patients with cancer, SV correlated with age (r = -0.45, p < 0.01) and body weight (r = +0.55, p = 0.0001). In chronic HF, SV declined with increasing age (r = -0.49, p < 0.01); in control subjects, SV increased with increasing body weight (r = +0.57, p = 0.01).

CONCLUSIONS

Patients with cancer tended to display elevated BP, CO, SV, and dP/dtmax as compared to control subjects and patients with HF. These findings may reveal an elevated risk for cardiovascular diseases in this group.

Systemic arterial waveform analysis and assessment of blood flow during extracorporeal circulation

BACKGROUND

The pressure recording analytical method (PRAM) is a method for real-time beat-to-beat quantification of peripheral blood flow based on the analysis of arterial waveform morphology. Since PRAM can be implemented in any conditions of flow, whether physiological or artificial, we assessed its accuracy in patients undergoing cardiac surgery during extracorporeal circulation (ECC), using the roller-pump device as the reference gold standard.

METHODS

We prospectively studied 32 patients undergoing elective coronary surgery. Flow values obtained by PRAM from the radial artery were compared with simultaneous values by thermodilution in physiological conditions of flow and with the roller-pump device readings during ECC.

RESULTS

Before and after ECC, the overall estimates of flow measured by PRAM closely agreed with thermodilution (mean difference 0.07 +/- 0.40 L/min). During ECC, PRAM estimates of flow also closely correlated with simultaneous pump readings (mean difference 0.11 +/- 0.33 L/min). At time of weaning from ECC, two patterns of hemodynamic adaptation were documented by PRAM following resumption of cardiac contraction: in most patients (n =26; 80%), cardiac output (CO) was stable (reduction < or = 10% compared to the steady ECC phase); six patients (20%) showed a fall in CO exceeding 10% and up to 38%.

CONCLUSIONS

PRAM provided accurate, continuous quantification of peripheral blood flow during each phase of cardiac surgery, including ECC, and allowed early recognition of patients with low CO during weaning from the pump.