An HIV positive male, admitted to the ICU with septic shock secondary to lobar pneumonia, is being mechanically ventilated. After 2 days of IV ceftriaxone, trimethoprim-sulfamethoxazole, and erythromycin, his fever has resolved. Blood cultures are positive for S. pneumoniae. SpO2 is 92% on room air and BP is 80/40 mm Hg, despite adequate fluids and 2 mcg/kg/min of norepinephrine. Fuher examination reveals warm skin and full peripheral pulses. What is the next best step in management?