Dear Editor,We read with great interest the brief case report by Carbonelli et al. [1] that highlights the pivotal role of a correct physical examination in the diagnosis of platypnea-orthodeoxia syndrome (P-OS) that occurred after a sublobar lung resection. The P-OS is a rare clinical manifestation characterized by dyspnea with a decrease in arterial blood oxygen saturation, which occur when the patient is sitting or standing up, and is relieved in the supine position [2]. It is frequently related to a patent foramen ovale (PFO), but it is itself not sufficient to produce clinically detectable issues (Fig. 1). Conditions leading to an increase in right heart pressures, such as pulmonary arteriovenous shunt, chronic obstructive pulmonary disease, surgical lung resection, pulmonary embolism, constrictive pericarditis, and kyphoscoliosis, can increase the right-to-left shunting, and may lead to a P-OS [3]. However, it is known that not all patients with P-OS have elevated right heart pre ...