One Pressure, Many Targets: Left Ventricular Filling Pressure as a Candidate Effect Modifier for Non-Invasive Ventilation in Acute Coronary Syndromes

Non-invasive ventilation relieves acute cardiogenic pulmonary edema and reduces intubation. Whether it saves lives is disputed; restricting the pooled record to the least biased trials leaves neither endpoint significant. My hypothesis: raising pleural pressure subtracts venous return; whether that subtraction is banked as unloading or paid as lost output depends on preload responsiveness, for which left ventricular filling pressure is a candidate effect modifier and not a measure. One radiographic label may contain two gas-exchange phenotypes, proposed for groups, not patients: carbon dioxide accumulates far more slowly than an ischemia-driven presentation floods the alveolus, and the remodeled ventricle arrives hypercapnic. Applied pressure inflates flooded air spaces without removing lung water, lowers left ventricular transmural pressure, and reaches two cardiac submechanisms. The left ventricular arm follows the sign rule; the renal arm follows it only through volume status; and in right ventricular infarction, the recorded filling pressure misleads, while the pulmonary arm does not reverse. In acute coronary syndromes, the first prediction fails if transmural pressure falls no more in the elevated than in the normal stratum, or if stroke volume index does not fall in the latter. The outer boundary is the requirement for emergency reperfusion, a limit inferred rather than measured directly.