In patients with CS secondary to acute myocardial infarction, the use of epinephrine compared with norepinephrine was associated with similar effects on arterial pressure and cardiac index and a higher incidence of refractory shock. (Study Comparing the Efficacy and Tolerability of Epinephrine and Norepinephrine in Cardiogenic Shock [OptimaCC]; NCT01367743).

When considering global hemodynamic effects, epinephrine is as effective as norepinephrine-dobutamine. Nevertheless, epinephrine is associated with a transient lactic acidosis, higher heart rate and arrhythmia, and inadequate gastric mucosa perfusion. Thus, the combination norepinephrine-dobutamine appears to be a more reliable and safer strategy.

Introduction. The PiCCO transpulmonary thermodilution technique provides two indices of cardiac systolic function, the cardiac function index (CFI) and the global ejection fraction (GEF). Both appear to be correlated with left ventricular ejection fraction (LVEF) measured by echocardiography in patients with circulatory failure, especially in septic shock. The aim of the present study was to test the reliability of CFI as an indicator of LVEF in patients with cardiogenic shock. Methods. In thirty-five patients with cardiogenic shock, we performed (i) simultaneous measurements of echocardiography LVEF and cardiac function index assessed by transpulmonary thermodilution (n = 72) and (ii) transpulmonary thermodilution before/after increasing inotropic agents (n = 18). Results. Mean LVEF was 31% (+/−11.7), CFI 3/min (+/−1), and GEF 14.2% (+/−6). CFI and GEF were both positively correlated with LVEF (P < 0.0001, r 2 = 0.27). CFI and GEF were significantly increased with inotropic infusion (resp., P = 0.005, P = 0.007). A cardiac function index <3.47/min predicted a left ventricular ejection fraction ≤35% (sensitivity 81.1% and specificity 63%). In patients with right ventricular dysfunction, CFI was not correlated with LVEF. Conclusion. CFI is correlated with LVEF provided that patient does not present severe right ventricular dysfunction. Thus, the PiCCO transpulmonary thermodilution technique is useful for the monitoring of inotropic therapy during cardiogenic shock.

Biguanide poisoning is associated with lactic acidosis. The exact mechanism of biguanide-induced lactic acidosis is not well understood. In the previous issue of Critical Care, Protti and colleagues demonstrated that biguanide-induced lactic acidosis may be due in part to a reversible inhibition of mitochondrial respiration. Thus, in the absence of an antidote, increased drug elimination through dialysis is logical.