The haemodynamics of septic shock.

Both peripheral vascular abnormalities and changes in myocardial function are hallmarks of septic shock. Their complex interactions result in inadequate and maldistributed microcirculatory flow and progressive organ dysfunction. Inappropriate vasodilation, microembolization and endothelial cell injury are proposed mechanisms that may induce maldistribution of flow in the microcirculation and inefficient, defective peripheral oxygen extraction. Abnormal myocardial function is manifested by diminished right and left ventricular ejection fractions, ventricular dilatation, altered Frank-Starling curves and diastolic pressure-volume relationships. These changes are already observed in an early stage of septic shock and are entirely reversible in survivors.