Eligibility Criteria
The indication for hospitalization according to the national protocol
was as follows: fever above 39° or being toxic in the examination,
respiratory distress, the use of respiratory muscle relaxants, the use
of suprasternal or intercostal retraction, a respiratory rate greater
than 30 per minute, a heart rate higher than 120 beats per minute, a
peripheral blood O2 saturation level less than 93%,
having an underlying disease (eg, diabetes, hypertension, heart failure,
immune system disorders, renal or hepatic impairment, a history of
asthma or chronic obstructive pulmonary disease, and smoking), age over
50 years in the case of being symptomatic, and the involvement of
one-third of 3 to 5 pulmonary lobes. The exclusion criteria were
composed of being a child, having unstable vital signs, being either
intubated or needing intubation, being admitted to the ICU, having
decreased levels of consciousness, having a respiratory rate greater
than 24, having a blood pressure level below 90/60 mm Hg, exhibiting
multi-lobular infiltration on CT scans or chest X-rays, having permanent
hypoxia, being pregnant or lactating, and having previous allergies to
NAC or glutathione-based drugs. The withdrawal criteria were comprised
of drug intolerance, severe complications probably related to NAC during
treatment, and unwillingness to continue collaboration with the study at
any point and for any reason.