On day 8, he had dyspnea after coming back from the bathroom, and became tachypneic (respiratory rate: 43 breaths per minute) and tachycardic (heart rate: 115 beats per minute), requiring 10 L of oxygen via the nonrebreather mask to maintain his SpO2 level above 94%. Chest auscultation showed diffuse bilateral crackles, and there were no signs of fluid overload. Arterial blood gas results were pH 7.48 (normal range: 7.35–7.45), pO2 63 mm Hg (normal range: 83–108), HCO3 27.4 mmol/L (normal range: 23–27) and pCO2 34 mm Hg (normal range: 35–45). The patient was given oxygen and salbutamol nebulization but without significant improvement. The repeated chest X-ray (Fig. 5) showed bilateral infiltrations and his calculated PaO2/FiO2 ratio = 143 (PaO2: 63 on 6 L oxygen, FiO2 44%). Cardiac causes have been ruled out, so he fulfilled the ARDS criteria. Moreover, he was still neutropenic, and his ferritin, LDH and triglyceride levels were elevated (Table 3). So, the patient was transferred to the intensive care unit.