Why measure cardiac output?

AUTOR(ES)

Pinsky, Michael R

FONTE

BioMed Central

RESUMO

Although cardiac output is a primary determinant of global O2 transport there are no absolute values that reflect circulatory adequacy, though very low values are of negative prognostic use. There is no agreement as to what constitutes a clinically relevant change in cardiac output. A recent clinical trial suggests that early goal-directed therapy aimed at increasing cardiac output improves survival. Thus, in some patients, measurement of cardiac output is indicated as an aid to prognosis, diagnosis and to monitor the adequacy of therapy. Gonzalez et al. compared PAC thermodilution cardiac output with indirect Fick measures of cardiac output. They found that at lower cardiac outputs (< 5 l/min) the agreement between the two techniques is good, whereas at higher flows increased differences exist between the two measures. As discussed in this commentary, this study did not address the three potential questions related to PAC monitoring of cardiac output. These questions are: can the PAC cardiac output data be used to monitor cardiac output? Do technical and physiological constraints limit the accuracy of PAC cardiac output? And; are PAC cardiac output measurement errors due to respiratory variation in pulmonary blood flow? Ways of answering each question are given.

Documentos Relacionados

• Post-prandial worsening of angina: all due to changes in cardiac output?
• Early diagnosis of myocardial infarction: why measure cardiac enzymes?
• Regional blood flow in chronic heart failure: the reason for the lack of correlation between patients' exercise tolerance and cardiac output?
• Do shocks permanently change output? Local persistency in economic time series
• Did the US boycott of French products spread to include scientific output?