Prediction of readiness to decannulation from venovenous extracorporeal membrane oxygenation.

OBJECTIVE: The criteria and process for liberation from extracorporeal membrane oxygenation in patients with severe acute respiratory distress syndrome are not standardized. The predictive accuracy of the oxygen challenge test as a diagnostic test in determining weaning and decannulation from venovenous extracorporeal membrane oxygenation was tested. DESIGN: A single-centre, retrospective, observational cohort study. SETTING: Tertiary referral severe respiratory failure centre in a university hospital in the United Kingdom. PATIENTS: 253 adults with severe acute respiratory distress syndrome requiring extracorporeal membrane oxygenation. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Patients had median age: 43 years (interquartile range: 32-52) years, extracorporeal membrane oxygenation days: 9 (interquartile range: 6-14) and acute physiology and chronic health evaluation II score 17.5 (interquartile range: 15-20). Oxygen challenge test value (PaO2-OCT) with best prediction was 31 kPa (232 mmHg; sensitivity 0.74; specificity 0.70; area under curve 0.77 (confidence interval: 0.73-0.81)). PaO2-OCT did not perform well as a prospective test to identify readiness to decannulation. Only 24 patients (10%) were decannulated 48 hours after their first positive oxygen challenge test (true positive) and 73.4% patients were false positives (positive oxygen challenge test but not decannulated). True positives had higher tidal volume (541 ± 218 vs 368 mL ± 210; p < 0.05) and minute ventilation (9.34 ± 5.36 vs 6.33 L/min ± 4.43; p < 0.05). Blood flow (3.17 ± 0.23 vs 3.53 L/min ± 0.56; p < 0.05), sweep gas flow (1.42 ±1.83 vs 3.74 L/min ± 2.43; p < 0.05) and extracorporeal membrane oxygenation minute volume at time of first positive oxygen challenge test was lower in true positives (1.66 ± 2.26 vs 4.82 ± 3.43 L/min). This was a strong predictor for decannulation within 48 hours (area under curve: 0.88, confidence interval: 0.88-0.89). CONCLUSIONS: In severe acute respiratory distress syndrome requiring venovenous extracorporeal membrane oxygenation, the PaO2-OCT is a poor predictor of readiness to decannulate from extracorporeal membrane oxygenation. Additional factors involved in the control of respiratory drive and carbon dioxide clearance, particularly native lung dead space and total minute ventilation, should be assessed.

An international survey: the role of specialist nurses in adult respiratory extracorporeal membrane oxygenation.

BACKGROUND: The last decade has seen an increase in the number of centres able to provide venovenous extracorporeal membrane oxygenation (VV-ECMO) internationally across different health care systems. To support this growth, a variety of staffing arrangements have been adopted depending on local need and availability of resources, both in terms of manpower and finances to safely meet the complex needs of the patient and circuit management. AIM: The aim of the survey was to describe current staffing arrangements of care provision for adult patients on VV-ECMO, with a focus on understanding the professional roles and responsibilities of staff managing the circuit in order to inform further discussion around different approaches to staffing. METHODS: We conducted a cross-sectional international survey using an electronic questionnaire emailed to 177 worldwide ECMO centres treating adult patients with acute respiratory failure. The survey questions were generated through an internal and external iterative process and assessed for clarity, content and face validity. RESULTS: The response rate was 82%. Respondents managed extracorporeal oxygenation for adult respiratory alone (75%) or in combination with adult cardiac (67%), paediatric respiratory (62%) and paediatric cardiac (58%). The specialist nurse to patient ratio was 1:1 in 59% of centres, with 24-h/day presence in 74%. Overall, the specialist nurse provided the 24-h/day management of the circuit, including interventions. Perfusionists were responsible for the technical aspects of circuit management. CONCLUSIONS: A specialist nurse with perfusion backup is the staffing arrangement implemented by most centres and likely reflects the most efficient use of the professional competences available. RELEVANCE TO CLINICAL PRACTICE: Staffing for adult respiratory extracorporeal support has important implications for the planning of workforce, training and education, quality of service and the number of ECMO beds available.