🫀Ventriculo-arterial coupling in septic shock: better cardiac efficiency does not necessarily mean better tissue perfusion One of the fundamental assumptions in septic shock resuscitation is that improving cardiac performance will restore peripheral perfusion. But is this physiological relationship as predictable as we believe? Thisnarticle explored the question in a prospective observational study during the first six hours of septic shock resuscitation. Left ventriculo-arterial coupling (LVAC) describes the interaction between arterial load (Ea) and ventricular end-systolic elastance (Ees): LVAC = Ea/Ees An elevated ratio indicates that arterial load is excessive relative to ventricular contractility, potentially compromising the efficiency of mechanical energy transfer. The investigators defined uncoupling as LVAC >1.36 and examined its relationship with capillary refill time (CRT). The results challenge a purely macrocirculatory approach. Patients transitioning from uncoupled to coupled exhibited a 33.8% reduction in CRT, accompanied by increased stroke volume, stroke work and ventricular efficiency. Conversely, patients developing uncoupling experienced a 17.5% prolongation of CRT. However, the overall correlation between changes in LVAC and CRT was weak and statistically nonsignificant Perhaps the most interesting finding concerns fluid responsiveness. In initially uncoupled patients, fluid administration increased stroke volume by 14%, yet CRT did not significantly improve. Dobutamine produced a comparable stroke volume increase of 14.2%, but was associated with a 26.2% reduction in CRT. This distinction is physiologically important. Increasing preload and increasing contractility can produce similar changes in stroke volume while exerting different effects on ventricular energetics, arterial interaction and peripheral perfusion. Nevertheless, these observational findings cannot establish that dobutamine is superior to fluids. The interventions were not randomized, and their clinical indications differed. What does this mean at the bedside? Fluid responsiveness identifies the capacity to increase cardiac output following preload augmentation. It does not establish that additional flow will improve tissue perfusion. Similarly, restoring ventriculo-arterial coupling may improve cardiovascular mechanical performance without necessarily correcting microvascular dysfunction. In septic shock, endothelial injury, heterogeneous capillary flow, altered vascular reactivity and impaired oxygen extraction may persist despite apparently favorable macrocirculatory changes. This study reinforces the importance of integrating echocardiography, arterial pressure, fluid responsiveness and peripheral perfusion rather than treating any single parameter as the ultimate resuscitation target. Reference📚 Caicedo Ruiz JD, et al. Annals of Intensive Care. 2026;16:100179. doi.org/10.1016/j.aicoj.2026…