Biochemical indicators of LV function during mechanical ventilatory support in critically ill adults

Introduction: The role of cardiac function is emerging as a poorly explored but potentially significant factor in ventilator dependence. Measuring LV function in the ICU is difficult. Therefore, surrogate biochemical markers were evaluated to determine if they correlate with standard measures and whether these surrogates can be used to predict duration of MVS especially in the absence of PA catheter. Methods: Blood samples for plasma norepmephnne levels (PNL) and atrial natnureuc peptade (ANP) were collected while hemodynamic parameters were observed using standard methods on the day following the initiation of mechanical ventilatory support. Results: PNL was significantly correlated with systemic vascular resistance (r - .57, p <.05, n = 14) and ANP was significantly correlated with PA occluded pressure (r - .42, p<.05, n=32). Of patients alive at 7 days after intubation (n=27), 66.7% of three with Day 1 PNLs ≤900 pg/L weaned from MVS within 7 days, while only 38.9% of those with Day 1 PNLs >900 pg/L did so. Conclusions: Biochemical indicators such as PNL and ANP may be useful in categorizing hemodynamic status in mechanically ventilated adults when a PA catheter IB not in place.