To the Editors:
Endotracheal intubation and mechanical ventilation are mainstays in the management of patients with acute respiratory distress syndrome (ARDS), but this treatment strategy exposes the patient to several risks and complications. A small number of ARDS patients can be treated with noninvasive ventilation and these patients have less ventilator-associated pneumonia and a lower mortality rate [1]. However, failure to improve oxygenation with noninvasive ventilation indicates the need for endotracheal intubation [1].
In patients with severe respiratory failure, extracorporeal membrane oxygenation (ECMO) is increasingly being used on top of mechanical ventilation to facilitate oxygenation and protective ventilation [2]. A novel concept is the use of ECMO in awake, spontaneously breathing patients to avoid the complications of invasive ventilation. So far, “awake ECMO” has been used predominantly in patients with end-stage lung disease as bridge to lung transplantation [3, 4]. The use of awake ECMO as bridge to recovery has recently been described in a patient with hypercapnic respiratory failure [5], but not yet in patients with ARDS.
We describe a patient with ARDS following septic shock who failed noninvasive ventilation and was successfully treated with awake ECMO, thereby avoiding endotracheal intubation and mechanical ventilation.
This 26-yr-old female was admitted to our hospital with urosepsis caused by Escherichia coli. Past medical history was remarkable for Ewing’s sarcoma, which had been treated with hemipelvectomy and radiochemotherapy 9 yrs previously, and had been in remission since then. On admission, the patient presented with septic shock. Initial therapy consisted of volume resuscitation, intravenous noradrenalin and antibiotics. At that time, the patient was mildly tachypnoeic but had clear lung fields on chest radiography and did not require supplemental oxygen therapy. On day 3, haemodynamics had stabilised and the patient no longer required vasopressors, but respiratory function progressively deteriorated. The patient became tachypnoeic and hypoxaemic with increasing oxygen demand. Chest radiography then demonstrated disseminated patchy infiltrates in all lung fields. Noninvasive ventilation via a sealed facemask was instituted and an inspiratory oxygen fraction (FI,O2) of 0.7 was required to maintain oxygen saturations at 90%. After 9 h on noninvasive ventilation, the patient became agitated and oxygenation deteriorated (minute ventilation 17 L·min−1; FI,O2 0.7; oxygen tension 50 mmHg; carbon dioxide tension 36 mmHg). Her Murray score at that time was 3 (arterial oxygen tension/FI,O2 ratio 71; diffuse infiltrates in all four quadrants; continuous positive airway pressure 6 cmH2O on non-invasive ventilation; lung compliance 23 mL·cmH2O−1) [6]. At that stage, the need for intubation was discussed with the patient, who vehemently declined. Therefore, we suggested initiating awake venovenous ECMO support, to which the patient agreed. Venous access was established via the left femoral and right internal jugular veins as described elsewhere [3]. The whole procedure was performed under local anaesthesia and low-dose analgosedation with 5 mg morphine and 200 mg propofol while the patient was still responsive and receiving noninvasive ventilation. Gas exchange improved immediately after ECMO insertion and the patient no longer required noninvasive ventilation. The patient felt comfortable (fig. 1), did not complain of dyspnoea and did not require sedation any more. Details of the ECMO settings and the further clinical course are shown in table 1. Gas exchange subsequently improved and, 4 days later, she was weaned from extracorporeal support. She fully recovered and was discharged from the hospital 8 days after decannulation.
To the best of our knowledge, this is the first report of awake ECMO in a patient with ARDS. Obviously, this strategy will not replace invasive ventilation as the standard ARDS treatment, but it may become a viable alternative in carefully selected candidates. Our patient had already recovered from septic shock and was no longer in a hypotensive and hyperdynamic circulatory state, which was probably a prerequisite for the high efficacy of ECMO support. Her prompt improvement and rapid recovery after ECMO insertion were remarkable and the course of ARDS in patients receiving ECMO support without invasive ventilation warrants further study. In patients with more severe lung injury one might also consider the use of ECMO in awake patients receiving noninvasive ventilation. To date, the use of ECMO in awake patients is investigational and must be carefully investigated before broader use.
Footnotes
Statement of Interest
None declared.
- ©ERS 2012