Negative- pressure pulmonary oedema after septoplasty

摘要

Negative pressure pulmonary oedema, an uncommon problem, occurs when large inspiratory force is generated against an obstructed upper airway resulting in decreased intra-thoracic pressure which increases venous return to the right heart and pulmonary capillary wedge pressure. It commonly involves young, healthy male patients undergoing general anaesthesia. Early diagnosis and prompt treatment are important to enhance recovery and prevent complications. We report a case of a 18 year old healthy, non-smoking male who developed negative pressure pulmonary oedema after septoplasty, and removal of neck swelling. With prompt diagnosis and appropriate treatment, the patient recovered well without significant sequelae. Introduction Negative-pressure pulmonary oedema (NPPE), first described by Oswalt in 1977 is a rare clinical entity 1 . The prevalence is less than 0.1% as a complication of all surgical procedures 2 . This form of non-cardiogenic pulmonary edema may result in immediate or delayed hypoxemia.We report a case of NPPE following septoplasy and removal of a neck swelling. With prompt diagnosis and appropriate treatment, the patient recovered well without significant sequelae. Case report An 18 year old, healthy, non-smoking man, weighing 44 kg, was admitted for septoplasty and removal of a neck swelling. He had an unremarkable medical history and physical examination. He was pre-medicated with alprazolam, 0.5 mg and metoclopramide, 10 mg, given orally one hour before surgery. Glycopyrrolate, 0.2 mg was given as an anti-sialogogue and tramadol, 100 mg was given for analgesia. After preoxygenation for 3 minutes, anaesthesia was induced with thiopentone, 200 mg and vecuronium, 5 mg was used to facilitate endotracheal intubation. The throat was packed with wet gauze after intubation.Anaesthesia was maintained with oxygen (O2), nitrous oxide (N2O), isoflurane and vecuronium. The procedure lasted approximately 60 minutes with minimal blood loss. A total of 700 ml of crystalloid was given as fluid replacement. The patient's intra-operative course was smooth with stable vital signs and oxygenation. At the end of the procedure, the throat pack was removed and the neuromuscular block was reversed with neostigmine, 2.5 mg and atropine, 1.2 mg. The patient was extubated after thorough oral suction and attainment of sufficient muscle power.While shifting the patient to recovery room, breath holding was observed. The pulse oximeter was reapplied which revealed oxygen saturation of 30% and immediately, bag and mask ventilation was resumed and oxygen saturation came up to 100%. Chest auscultation revealed bilateral rhonchi. Deriphylline (etofylline 84.7 mg and theophylline 25.3 mg) and hydrocortisone, 100 mg were given. After a few minutes, the patient started breathing spontaneously. At this time, chest auscultation revealed bilateral basal crepts. Furosemide, 20 mg was given while the patient was ventilated with bag and mask. Suddenly, the patient coughed out copious amount of pink, frothy sputum suggestive of pulmonary oedema.The patient was re-intubated after giving thiopentone and succinylcholine. Endotracheal suction was done which kept pouring pink frothy secretions. Chest auscultation was repeated which revealed bilateral coarse crepts. Furosemide, 40 mg was given. The patient was shifted to intensive care unit (ICU) for elective mechanical ventilation.An immediate cardiac consultation was done which showed no obvious cardiac cause for patient's pulmonary oedema. The patient's arterial blood gas (ABG) report on arrival in ICU revealed a pH of 7.34 with carbon dioxide tension (pCO2) of 53.2 mm Hg and an oxygen tension (pO2) of 338.5 mm Hg with no base deficit. The chest radiograph revealed bilateral diffuse pulmonary infiltrates consistent with pulmonary oedema (Figure 1).