Arterial dP/dt(max )accurately reflects left ventricular contractility during shock when adequate vascular filling is achieved

BACKGROUND: Peak first derivative of femoral artery pressure (arterial dP/dt(max)) derived from fluid-filled catheter remains questionable to assess left ventricular (LV) contractility during shock. The aim of this study was to test if arterial dP/dt(max )is reliable for assessing LV contractility during various hemodynamic conditions such as endotoxin-induced shock and catecholamine infusion. METHODS: Ventricular pressure-volume data obtained with a conductance catheter and invasive arterial pressure obtained with a fluid-filled catheter were continuously recorded in 6 anaesthetized and mechanically ventilated pigs. After a stabilization period, endotoxin was infused to induce shock. Catecholamines were transiently administrated during shock. Arterial dP/dt(max )was compared to end-systolic elastance (Ees), the gold standard method for assessing LV contractility. RESULTS: Endotoxin-induced shock and catecholamine infusion lead to significant variations in LV contractility. Overall, significant correlation (r = 0.51; p < 0.001) but low agreement between the two methods were observed. However, a far better correlation with a good agreement were observed when positive-pressure ventilation induced an arterial pulse pressure variation (PPV) ≤ 11% (r = 0.77; p < 0.001). CONCLUSION: While arterial dP/dt(max )and Ees were significantly correlated during various hemodynamic conditions, arterial dP/dt(max )was more accurate for assessing LV contractility when adequate vascular filling, defined as PPV ≤ 11%, was achieved.