Pope Francis, hospitalised with pneumonia in both lungs, slept “all night long and continues to rest” after suffering two bouts of acute respiratory failure, the Vatican said on Tuesday.

The 88-year-old pope was admitted to Rome’s Gemelli hospital on February 14 with bronchitis, which developed into pneumonia in both lungs, sparking alarm across the globe.

On Monday, the pope “experienced two episodes of acute respiratory failure, caused by a significant accumulation of endobronchial mucus and consequent bronchospasm,” the Vatican had said in its evening update.

Acute respiratory failure, which can be life-threatening, occurs when the lungs cannot pass enough oxygen into the blood, or when carbon dioxide builds up in the body.

The Vatican added that Francis’ prognosis remained “reserved”, an indication that doctors could not predict the likely outcome of his condition.