A 72-year-old man on ICU with septic shock has received aggressive fluid resuscitation (50 mL/kg) over 6 hours. His CVP is 14 mmHg, MAP is 62 mmHg on noradrenaline 0.15 mcg/kg/min, and ScvO2 is 68%. A passive leg raise test shows no increase in cardiac output. What does the PLR result indicate about further fluid management?