In the per protocol analysis for the subgroup with
confirmed chronic obstructive pulmonary disease, we
found significant differences between treatment arms
for blood gas measurements (table 4). Patients who
received titrated oxygen were significantly less likely
to have respiratory acidosis (P= 0.01) due to acute
hypercapnia (P= 0.02) than were patients who received
high flow oxygen. We found no significant differences
between treatment arms in length of hospital stay or
requirement for ventilation for all patients or the subgroup with confirmed chronic obstructive pulmonary
disease (table 4). Death rates were similar to those seen
in the intention to treat analysis for all patients and the
subgroup with confirmed chronic obstructive pulmonary disease, although the differences did not reach statistical significance (table 4).