Asthma, Ecmo And Eosinophils

A man in his 30s, with a history of mild childhood asthma only, went to his local hospital with difficulty in breathing. His presentation was preceded by 6 days of worsening breathlessness, wheeze and cough. He had been using his mother’s salbutamol inhaler and received oral amoxicillin in the community. He was hypertensive, tachycardic and had a respiratory rate of 32 breaths/min. He could not complete sentences, peak flow measurement or lie flat. Chest auscultation revealed diffuse polyphonic wheeze. Arterial blood gas (ABG) while receiving fraction of inspired oxygen (FiO2) 40% revealed pH 7.32, PaO2 9.7 kPa, PaCO2 6.7 kPa. He had a blood eosinophil count of 0.5×109/L, serum C-reactive protein of 30 mg/L with normal renal and liver profiles. His chest radiograph (figure 1A) revealed clear lung fields with no pneumothorax or consolidation. He was treated with nebulised bronchodilators, intravenous broad-spectrum antibiotics, magnesium, hydrocortisone and aminophylline before transfer to the high dependency unit.\n\n\n\nFigure 1 \n(A) Presentation chest radiograph. (B) CT thorax, day 1 extracorporeal membrane oxygenation (ECMO) treatment. (C) Summary of antibiotic and steroid therapy, change in blood eosinophil and bronchoalveolar lavage (BAL) % and ECMO sweep requirements (necessary to clear CO2). Shaded area is time spent on ECMO. Key: MP, methylprednisolone; Vc, vancomycin (D). Eosinophil-rich BAL.\n\n\n\nOver 48 hours, there was an improvement and treatments were gradually weaned but on day 3 there was a respiratory deterioration associated with a PaCO2 of 7.6 kPa requiring intubation. Treatment was augmented with a ketamine infusion and inhaled sevoflurane. Despite optimum ventilation strategies, 4 hours after intubation there was severe gas trapping requiring manual decompression, low tidal volumes and a rising arterial PaCO2. A referral to the local extracorporeal membrane oxygenation (ECMO) centre was made.\n\nOn our arrival, the patient was in ventilatory failure with severe gas trapping. Pre-ECMO …