What are the clues to distinguish between a cardiac and respiratory problem in emergency situations?

The sound emitted by the patient when breathing can indicate a problem in the upper airways (pharynx, larynx, trachea).
If the sounds are more evident ventrally than dorsally, there is probably a pneumothorax.
Patients with non-cardiogenic respiratory pathology usually have a palpable femoral pulse with a normal or increased frequency and normal or increased temperature.
Patients with cardiogenic pulmonary edema often present with crepitus in the perihilar area (around the sixth intercostal space) and a holosystolic heart murmur.
Patients with inflammatory systemic disease may cause acute respiratory distress syndrome (ARDS) or pulmonary thromboembolism, characterized by harsh and hard sounds on auscultation.