title: Feasibility and safety of low-flow extracorporeal carbon dioxide removal to facilitate ultra-protective ventilation in patients with moderate acute respiratory distress sindrome.
abstract: BACKGROUND
  Mechanical ventilation with a tidal volume (VT) of 6 mL/kg/predicted body weight (PBW), to maintain plateau pressure (Pplat) lower than 30 cmH2O, does not completely avoid the risk of ventilator induced lung injury (VILI). The aim of this study was to evaluate safety and feasibility of a ventilation strategy consisting of very low VT combined with extracorporeal carbon dioxide removal (ECCO2R).
  
  
  METHODS
  In fifteen patients with moderate ARDS, VT was reduced from baseline to 4 mL/kg PBW while PEEP was increased to target a plateau pressure--(Pplat) between 23 and 25 cmH2O. Low-flow ECCO2R was initiated when respiratory acidosis developed (pH < 7.25, PaCO2 > 60 mmHg). Ventilation parameters (VT, respiratory rate, PEEP), respiratory compliance (CRS), driving pressure (DeltaP = VT/CRS), arterial blood gases, and ECCO2R system operational characteristics were collected during the period of ultra-protective ventilation. Patients were weaned from ECCO2R when PaO2/FiO2 was higher than 200 and could tolerate conventional ventilation settings. Complications, mortality at day 28, need for prone positioning and extracorporeal membrane oxygenation, and data on weaning from both MV and ECCO2R were also collected.
  
  
  RESULTS
  During the 2 h run in phase, VT reduction from baseline (6.2 mL/kg PBW) to approximately 4 mL/kg PBW caused respiratory acidosis (pH < 7.25) in all fifteen patients. At steady state, ECCO2R with an average blood flow of 435 mL/min and sweep gas flow of 10 L/min was effective at correcting pH and PaCO2 to within 10 % of baseline values. PEEP values tended to increase at VT of 4 mL/kg from 12.2 to 14.5 cmH2O, but this change was not statistically significant. Driving pressure was significantly reduced during the first two days compared to baseline (from 13.9 to 11.6 cmH2O; p < 0.05) and there were no significant differences in the values of respiratory system compliance. Rescue therapies for life threatening hypoxemia such as prone position and ECMO were necessary in four and two patients, respectively. Only two study-related adverse events were observed (intravascular hemolysis and femoral catheter kinking).
  
  
  CONCLUSIONS
  The low-flow ECCO2R system safely facilitates a low volume, low pressure ultra-protective mechanical ventilation strategy in patients with moderate ARDS.
authors: Department of Anesthesia and Critical Care - AOU Città della Salute e della Scienza di Torino, University of Turin, Corso Dogliotti 14, 10126, Torino, Italy. vito.fanelli@unito.it.
authors: Vito
authors: V
authors: Fanelli
authors: Dipartimento di Anestesia e Rianimazione, Ospedale Policlinico Umberto I, Sapienza Università di Roma, Rome, Italy.
authors: Marco V
authors: MV
authors: Ranieri
authors: Servei de Medicina Intensiva, Hospital de Sant Pau, Barcelona, Spain.
authors: Jordi
authors: J
authors: Mancebo
authors: Department of Anesthesiology, Emergency and Intensive Care Medicine, University Medical Center Göttingen, Göttingen, Germany.
authors: Onnen
authors: O
authors: Moerer
authors: Department of Anesthesiology, Emergency and Intensive Care Medicine, University Medical Center Göttingen, Göttingen, Germany.
authors: Michael
authors: M
authors: Quintel
authors: ALung Technologies, Pittsburgh, USA.
authors: Scott
authors: S
authors: Morley
authors: Servei de Medicina Intensiva, Hospital de Sant Pau, Barcelona, Spain.
authors: Indalecio
authors: I
authors: Moran
authors: Servei de Medicina Intensiva, Hospital de Sant Pau, Barcelona, Spain.
authors: Francisco
authors: F
authors: Parrilla
authors: Department of Anesthesia and Critical Care - AOU Città della Salute e della Scienza di Torino, University of Turin, Corso Dogliotti 14, 10126, Torino, Italy.
authors: Andrea
authors: A
authors: Costamagna
authors: Department of Anesthesia and Critical Care - AOU Città della Salute e della Scienza di Torino, University of Turin, Corso Dogliotti 14, 10126, Torino, Italy.
authors: Marco
authors: M
authors: Gaudiosi
authors: Service de Réanimation Médicale, iCAN, Institute of Cardiometabolism and Nutrition, Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors: Alain
authors: A
authors: Combes
mesh_terms: D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000378:metabolism* / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012121:Respiration, Artificial / Q000009:adverse effects / Q000379:methods*; D012128:Respiratory Distress Syndrome / Q000628:therapy*; D015656:Respiratory Mechanics / Q000502:physiology; D013990:Tidal Volume / Q000502:physiology; D055397:Ventilator-Induced Lung Injury / Q000517:prevention & control*
chemical_list: D002245:Carbon Dioxide