Evaluation of cardiac performance in hemodynamically unstable patients with septic shock

ABSTRACT

Septic shock is characterized by bi-ventricular dysfunction within the first 24 hours after its onset due to circulating mediators, myocardial ischemia and micorvascular dysfunction. The aim of this study was to assess the cardiac functions in patients with septic shock and the prognostic effect of its derangement. Eighteen patients with septic shock were studied at the Critical Medicine Department at Alexandria, Main University hospital. Clinical evaluation of the severity of illness was done using the Simplified Acute Physiology Score, as well as hemodynamic assessment by Swan-Ganz catheter and echocardiography on admission, after 24 and 48 hours. All patients were put on Dobutamine and Dopamine infusions on admission. If shock persisted, adrenaline was infused. The ejection fraction decreased in all patients, and was paradoxically lower in those who survived. The total peripheral resistance increased with treatment in patients who finally survived, but continued to diminish in non-survivors. The changes in stroke volume, cardiac output and cardiac index with treatment were insignificant in both groups. After 24 hours, 14 patients did not respond to treatment with significant diminution in the peripheral resistance. Cardiac dysfunction in septic shock is characterized by peripheral vasodilatation and impaired global performance. This transient vasodilatation may be an adaptive mechanism to maintain cardiac output. The left ventricular ejection fraction is depressed in the initial phase of septic shock, and is more markedly depressed in patients who ultimately will recover. An increasing systemic vascular resistance during the course of septic shock is an important marker in the improvement of survival rate