Which of the following is the first sign seen in aspiration pneumonitis?

Though tachycardia and wheeze are usually seen, tachyponea is usually the first sign. Aspiration of gastric acid causes chemical pneumonia, which has also been called aspiration pneumonitis (Mendelson's syndrome). In fact, aspiration of a massive amount of gastric contents can produce acute respiratory distress within 1 hour. The acidity of gastric contents results in chemical burns to the tracheobronchial tree involved in the aspiration. If the pH of the aspirated fluid is less than 2.5 and the volume of aspirate is greater than 0.3 mL/kg of body weight (20-25 mL in adults), it has a greater potential for causing chemical pneumonia. The initial chemical burn is followed by an inflammatory cellular reaction fueled by the release of potent cytokines, paicularly tumor necrosis factor (TNF)-alpha and interleukin (IL)-8.