Ventilatory and ECMO treatment of H1N1-induced severe respiratory failure: results of an Italian referral ECMO center

Abstract

BackgroundSince the first outbreak of a respiratory illness caused by H1N1 virus in Mexico, several reports have described the need of intensive care or extracorporeal membrane oxygenation (ECMO) assistance in young and often healthy patients. Here we describe our experience in H1N1-induced ARDS using both ventilation strategy and ECMO assistance.MethodsFollowing Italian Ministry of Health instructions, an Emergency Service was established at the Careggi Teaching Hospital (Florence, Italy) for the novel pandemic influenza. From Sept 09 to Jan 10, all patients admitted to our Intensive Care Unit (ICU) of the Emergency Department with ARDS due to H1N1 infection were studied. All ECMO treatments were veno-venous. H1N1 infection was confirmed by PCR assayed on pharyngeal swab, subglottic aspiration and bronchoalveolar lavage. Lung pathology was evaluated daily by lung ultrasound (LUS) examination.ResultsA total of 12 patients were studied: 7 underwent ECMO treatment, and 5 responded to protective mechanical ventilation. Two patients had co-infection by Legionella Pneumophila. One woman was pregnant. In our series, PCR from bronchoalveolar lavage had a 100% sensitivity compared to 75% from pharyngeal swab samples. The routine use of LUS limited the number of chest X-ray examinations and decreased transportation to radiology for CT-scan, increasing patient safety and avoiding the transitory disconnection from ventilator. No major complications occurred during ECMO treatments. In three cases, bleeding from vascular access sites due to heparin infusion required blood transfusions. Overall mortality rate was 8.3%.ConclusionsIn our experience, early ECMO assistance resulted safe and feasible, considering the life threatening condition, in H1N1-induced ARDS. Lung ultrasound is an effective mean for daily assessment of ARDS patients.

Stress and strain within the lung

“…It appears, therefore, that there is an increasing trend to consider lung stress and strain, at least in their global expression, as a meaningful tool to tailor a well tolerated mechanical ventilation instead of employing plateau airway pressures and tidal volume as standardized on ideal body weight. In this light, it is interesting to note that, in patients with severe respiratory failure due to H1N1 pandemia, there has been an increasing use of extracorporeal membrane lung oxygenation [32,33], which allows a complete control and limitation of lung stress and strain [34].…”

Clinical review: Extracorporeal membrane oxygenation

“…Some papers specified more details, which are still in line with lung-protective strategies aiming for a further reduction of tidal volume (for example, 3 to 5 ml/kg ideal body weight) while maintaining relative high mean airway pressure by high positive end-expiratory pressure (PEEP). In this scenario, however, we may find extreme differences [15,36,40-42]. As an example, in several centers in Italy it was not uncommon to observe very low tidal volumes with the respiratory rate limited to 7 or 8 breaths/minute and a high mean airway pressure related to high PEEP application.…”

Transferring Patients With Refractory Hypoxemia to a Regional Extracorporeal Membrane Oxygenation Center

“…25 , 26 Later studies suggested a benefit to patients with severe ARDS, [27][28][29][30][31] whereas other studies revealed mixed results. [32][33][34] However, ECMO therapy gained worldwide attention as a treatment option during the 2009 H1N1 pandemic, and interest was rekindled in its use for other cases of refractory hypoxemia. 3 , 6 , 8 The study by Peek et al 3 was the only controlled clinical trial that used modern ECMO technology to treat ARDS from various causes.…”