title: Apnea test during brain death assessment in mechanically ventilated and ECMO patients.
abstract: OBJECTIVE
  To evaluate the feasibility and efficacy of an apnea test (AT) technique that combines the application of positive end expiratory pressure (PEEP) with subsequent pulmonary recruitment in a large cohort of brain-dead patients.
  
  
  METHODS
  This study was a retrospective analysis of prospectively collected data on brain-dead patients admitted to our institution (Hospital San Gerardo, Monza, Italy) between January 2010 and December 2014. The rate of aborted apnea tests (ATs), occurrence of complications (i.e., pneumothorax, cardiac arrhythmias, cardiac arrest, and severe hypoxia, defined as PaO2 < 40 mmHg), ventilator settings, hemodynamics, and blood gas analyses were evaluated. Subgroup analysis was performed, with patients classified into veno-arterial extracorporeal membrane oxygenation (ECMO) or non-ECMO groups, and into hypoxic (i.e., baseline PaO2/FiO2 < 200 mmHg) and non-hypoxic (i.e., baseline PaO2/FiO2 > 200 mmHg) groups.
  
  
  RESULTS
  In total, 169 consecutive patients including 25 on ECMO were included in the study. No AT abortion nor severe complications were detected. The AT was completed in all patients. Fluid boluses and increases or initiation of vasoactive drugs were required in less than 10 and 3% of the AT procedures, respectively. No clinically meaningful alteration in hemodynamics was recorded. Severe hypoxia occurred during 7 (2.4%) and 4 (8%) of the ATs performed in non-ECMO and ECMO patients, respectively (p = 0.063), and it occurred more frequently in hypoxic patients than in non-hypoxic patients (11.1 vs. 4.8%, respectively; p = 0.002).
  
  
  CONCLUSIONS
  In a large cohort of consecutive patients, including the largest patient population on ECMO reported to date, our AT technique that combines the application of PEEP with subsequent pulmonary recruitment proved to be feasible and safe.
authors.affiliation: School of Medicine and Surgery, University of Milan-Bicocca, Via Cadore 48, 20900, Monza, Italy. marco.giani84@gmail.com.|Department of Anesthesia and Intensive Care, IRCCS San Raffaele Hospital, Vita-Salute University, Via Olgettina 60, 20132, Milan, Italy. marco.giani84@gmail.com.
authors.forename: Marco
authors.initials: M
authors.lastname: Giani
authors.affiliation: School of Medicine and Surgery, University of Milan-Bicocca, Via Cadore 48, 20900, Monza, Italy. vittorio.scaravilli@gmail.com.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Scaravilli
authors.affiliation: School of Medicine and Surgery, University of Milan-Bicocca, Via Cadore 48, 20900, Monza, Italy. sebastiano.colombo@gmail.com.
authors.forename: Sebastiano Maria
authors.initials: SM
authors.lastname: Colombo
authors.affiliation: Neurointensive Care, Department of Emergency and Intensive Care, San Gerardo Hospital, Via Pergolesi 33, 20900, Monza (MB), Italy. andreaconfa@gmail.com.
authors.forename: Andrea
authors.initials: A
authors.lastname: Confalonieri
authors.affiliation: School of Medicine and Surgery, University of Milan-Bicocca, Via Cadore 48, 20900, Monza, Italy. rosambra.leo@gmail.com.
authors.forename: Rosambra
authors.initials: R
authors.lastname: Leo
authors.affiliation: Cardiac Surgical Intensive Care Unit, Department of Emergency and Intensive Care, San Gerardo Hospital, Via Pergolesi 33, 20900, Monza (MB), Italy. elenamaggioni75@libero.it.
authors.forename: Elena
authors.initials: E
authors.lastname: Maggioni
authors.affiliation: Cardiac Surgical Intensive Care Unit, Department of Emergency and Intensive Care, San Gerardo Hospital, Via Pergolesi 33, 20900, Monza (MB), Italy. l.avalli@hsgerardo.org.
authors.forename: Leonello
authors.initials: L
authors.lastname: Avalli
authors.affiliation: Neurointensive Care, Department of Emergency and Intensive Care, San Gerardo Hospital, Via Pergolesi 33, 20900, Monza (MB), Italy. neurorianimazione@hsgerardo.org.
authors.forename: Alessia
authors.initials: A
authors.lastname: Vargiolu
authors.affiliation: School of Medicine and Surgery, University of Milan-Bicocca, Via Cadore 48, 20900, Monza, Italy. giuseppe.citerio@unimib.it.|Neurointensive Care, Department of Emergency and Intensive Care, San Gerardo Hospital, Via Pergolesi 33, 20900, Monza (MB), Italy. giuseppe.citerio@unimib.it.
authors.forename: Giuseppe
authors.identifier: http://orcid.org/0000-0002-5374-3161
authors.initials: G
authors.lastname: Citerio
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001049:Apnea / Q000175:diagnosis*; D001926:Brain Death / Q000175:diagnosis* / Q000331:legislation & jurisprudence; D002423:Cause of Death; D015199:Extracorporeal Membrane Oxygenation / Q000379:methods*; D005260:Female; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000379:methods; D012121:Respiration, Artificial / Q000379:methods*; D012189:Retrospective Studies
keywords: Apnea; Brain death; Extracorporeal membrane oxygenation; Mechanical ventilation