All the patients exhibited a severe metabolic acidosis with the BE range from -16.0 to -4.4 mmol/L (median, -10.3 mmol/L) upon admission. The acid-base disturbances were maintained with the BE range from -14.4 to -4.1 mmol/L (median, -7.6 mmol/L) at 3 hours, and from -15.2 to -3.1 mmol/L (median, -4.7 mmol/L) at 12 hours after admission with infusion of fluids and/or norepinephrine. The metabolic acidosis was refractory to intensive treatment with mechanical ventilation, infusion of fluids and/or norepinephrine at 24 hours with the BE range from -8.3 to -3.1 mmol/L (median, -4.9 mmol/L; Figure  1 ). Sodium bicarbonate for metabolic acidosis was not administered because the blood pH was kept in the normal range (7.35-7.45) with effective ventilation.