Septic shock is associated with severe hypotension, and tissue hypoperfusion . If this is not rapidly corrected, will lead to organ failure and often death. Septic shock is characterized by the requirement for vasopressors to maintain a mean arterial pressure of over 65 mmhg , and a serum lactate level of over 2mmol/l, in the absence of hypovolaemia.(1) In the early stages of sepsis, there is a high cardiac output, vaso dilatation and warm extremities. This is followed by, hypotension, low cardiac output, poor peripheral perfusion and cold extremities (2) The cardio vascular dysfunction which occurs in sepsis is responsible for the causation of multiple organ failure and its correct management is therefore crucial for a successful…show more content… These are, left ventricular dilatation, a depressed contractility and recovery in 7-10 days along with the resolution of sepsis.(11) In contrast to cardiogenic shock, the left ventricular filling pressures are low or normal.(11). This is probably due to an increase in left ventricular compliance. (9) The contractility is decreased. Both end systolic and end diastolic volumes are increased. The stroke volume and cardiac index are increased. (9) It has been demonstrated that both right and left ventricular contractility is decreased in septic shock.(12) Right ventricular dilatation can also occur. (13)).It has been shown that nearly 30% of septic shock patients have right ventricular dilatation. This implies right ventricular dysfunction.(14) The third feature is that it is reversible with recovery from…show more content… (18) A decrease in the afterload, would mean that the heart pumps against a lowered resistance and therefore a given volume would have an increased output as against a normal situation.
Therefore with the severe drop in afterload in septic shock, the Frank Starling curve will be shifted up and to the left. This can occur even if the myocardium is dysfunctional. The severe drop in afterload may compensate for the loss of contractility of the myocardium. This would give the impression that cardiac function is satisfactory. The shift in the curve upward and to the left, will also indicate a greater fluid responsiveness. The associated right ventricular dysfunction will also show a false fluid responsiveness.(19).Inappropriate fluid resuscitation can occur under these circumstances.
The cardiac function curve would therefore be an inappropriate method to assess cardiac function in septic shock.
This would also mean, that the left ventricular ejection fraction, may appear normal despite an actual depression of contractility. Therefore in septic shock, a normal ejection fraction, and a high stroke volume and cardiac index maybe obtained because of the aforesaid reasons. The left ventricular ejection fraction is not a reliable index of LV systolic function in septic
