A narrowed pulse pressure (≤20-25 mmHg) is suggestive of decreased stroke volume. It may be a manifestation of pericardial tamponade, constrictive pericarditis, tachycardia, aortic stenosis, hypovolemia, increased peripheral vascular resistance as seen in early septic shock, or decreased stroke volume. Pay attention to narrowed pulse pressure in the sick appearing and trauma patient.
Roberts: Clinical Procedures in Emergency Medicine, 5th ed.
Jane M. Orient: Sapira’s Art & Science of Bedside Diagnosis, 3rd ed.