ICU Physiology in 1,000 Words: The Right Ventricular Afterload (Part 1 of 2) By Jon-Emile S. Kenny M.D. With my trusted-resident – Dr. Lina Miyakawa – at my side we watched as our patient could not maintain his oxygen saturation above 82%. The patient had terrible aspiration pneumonia superimposed upon horrendous methamphetamine-related pulmonary arterial hypertension [PAH]. With cardiac anesthesia preparing to intubate, Lina and I were told that paralysis was important for if the patient were to Valsalva, his pulmonary arterial pressures would shoot up, raise his right ventricular afterload and plummet his cardiac output; the reasoning didn’t sit well with me, however.