Aspiration Pneumonitis

A 58-year-old man with a history of gastroesophageal reflux disease (GERD) and hiatal hernia is scheduled for elective laparoscopic cholecystectomy under general anesthesia. Preoperative assessment reveals he took a heavy meal 3 hours before arriving at the hospital. During rapid sequence intubation, aspiration of gastric contents occurs despite proper cricoid pressure. Within 2 hours of surgery, the patient develops acute hypoxemia (SpO₂ 88% on FiO₂ 0.6), bilateral crackles on auscultation, and frothy sputum. Chest X-ray shows bilateral infiltrates predominantly in dependent lung zones. What is the most appropriate immediate management?

A 42-year-old woman with uncontrolled diabetes mellitus and obesity (BMI 34 kg/m²) undergoes emergency cesarean section under general anesthesia for fetal distress. She had consumed a large meal 2 hours before admission. During induction, despite rapid sequence intubation with cricoid pressure, aspiration of gastric contents occurs. The anesthesiologist notes particulate matter in the oropharynx. Six hours postoperatively, the patient develops fever (38.5°C), tachycardia (110 bpm), and productive cough with purulent sputum. Chest X-ray shows new infiltrates in the right lower lobe. What is the most likely diagnosis and the next appropriate step?

In the context of aspiration pneumonitis prevention, what is the minimum fasting period recommended before elective surgery under general anesthesia to reduce gastric volume and aspiration risk?