Joao Henrique Neves Soares1,2, Alysson Roncally Carvalho3,4, Bruno Curty Bergamini3, Maria Alice Kuster Gress5, Frederico Caetano Jandre3, Walter Araujo Zin4, Antonio Giannella-Neto3. 1. Laboratory of Pulmonary Engineering, Biomedical Engineering Program/COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, 22210-03, Brazil. jhsoares@vt.edu. 2. Department of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA. jhsoares@vt.edu. 3. Laboratory of Pulmonary Engineering, Biomedical Engineering Program/COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, 22210-03, Brazil. 4. Laboratory of Respiration Physiology, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, 22210-03, Brazil. 5. Laboratory of Animal Research, Veterinary School, Fluminense Federal University, Niteroi, RJ, 24320-340, Brazil.
Abstract
PURPOSE: We compared respiratory mechanics between the positive end-expiratory pressure of minimal respiratory system elastance (PEEPminErs) and three levels of PEEP during low-tidal-volume (6 mL/kg) ventilation in rats. METHODS: Twenty-four rats were anesthetized, paralyzed, and mechanically ventilated. Airway pressure (Paw), flow (F), and volume (V) were fitted by a linear single compartment model (LSCM) Paw(t) = Ers × V(t) + Rrs × F(t) + PEEP or a volume- and flow-dependent SCM (VFDSCM) Paw(t) = (E1 + E2 × V(t)) × V(t) + (K1 + K2 × |F(t)|) × F(t) + PEEP, where Ers and Rrs are respiratory system elastance and resistance, respectively; E1 and E2× V are volume-independent and volume-dependent Ers, respectively; and K1 and K2 × F are flow-independent and flow-dependent Rrs, respectively. Animals were ventilated for 1 h at PEEP 0 cmH2O (ZEEP); PEEPminErs; 2 cmH2O above PEEPminErs (PEEPminErs+2); or 4 cmH2O above PEEPminErs (PEEPminErs+4). Alveolar tidal recruitment/derecruitment and overdistension were assessed by the index %E2 = 100 × [(E2 × VT)/(E1 + |E2| × VT)], and alveolar stability by the slope of Ers(t). RESULTS: %E2 varied between 0 and 30% at PEEPminErs in most respiratory cycles. Alveolar Tidal recruitment/derecruitment (%E2 < 0) and overdistension (%E2 > 30) were predominant in the absence of PEEP and in PEEP levels higher than PEEPminErs, respectively. The slope of Ers(t) was different from zero in all groups besides PEEPminErs+4. CONCLUSIONS: PEEPminErs presented the best compromise between alveolar tidal recruitment/derecruitment and overdistension, during 1 h of low-VT mechanical ventilation.
PURPOSE: We compared respiratory mechanics between the positive end-expiratory pressure of minimal respiratory system elastance (PEEPminErs) and three levels of PEEP during low-tidal-volume (6 mL/kg) ventilation in rats. METHODS: Twenty-four rats were anesthetized, paralyzed, and mechanically ventilated. Airway pressure (Paw), flow (F), and volume (V) were fitted by a linear single compartment model (LSCM) Paw(t) = Ers × V(t) + Rrs × F(t) + PEEP or a volume- and flow-dependent SCM (VFDSCM) Paw(t) = (E1 + E2 × V(t)) × V(t) + (K1 + K2 × |F(t)|) × F(t) + PEEP, where Ers and Rrs are respiratory system elastance and resistance, respectively; E1 and E2× V are volume-independent and volume-dependent Ers, respectively; and K1 and K2 × F are flow-independent and flow-dependent Rrs, respectively. Animals were ventilated for 1 h at PEEP 0 cmH2O (ZEEP); PEEPminErs; 2 cmH2O above PEEPminErs (PEEPminErs+2); or 4 cmH2O above PEEPminErs (PEEPminErs+4). Alveolar tidal recruitment/derecruitment and overdistension were assessed by the index %E2 = 100 × [(E2 × VT)/(E1 + |E2| × VT)], and alveolar stability by the slope of Ers(t). RESULTS: %E2 varied between 0 and 30% at PEEPminErs in most respiratory cycles. Alveolar Tidal recruitment/derecruitment (%E2 < 0) and overdistension (%E2 > 30) were predominant in the absence of PEEP and in PEEP levels higher than PEEPminErs, respectively. The slope of Ers(t) was different from zero in all groups besides PEEPminErs+4. CONCLUSIONS: PEEPminErs presented the best compromise between alveolar tidal recruitment/derecruitment and overdistension, during 1 h of low-VT mechanical ventilation.
Entities:
Keywords:
Alveolar overdistention; Anesthesia; PEEP choice; Protective ventilation; Tidal recruitment/derecruitment
Authors: Marcelo B P Amato; Maureen O Meade; Arthur S Slutsky; Laurent Brochard; Eduardo L V Costa; David A Schoenfeld; Thomas E Stewart; Matthias Briel; Daniel Talmor; Alain Mercat; Jean-Christophe M Richard; Carlos R R Carvalho; Roy G Brower Journal: N Engl J Med Date: 2015-02-19 Impact factor: 91.245
Authors: Esther K Wolthuis; Goda Choi; Mark C Dessing; Paul Bresser; Rene Lutter; Misa Dzoljic; Tom van der Poll; Margreeth B Vroom; Markus Hollmann; Marcus J Schultz Journal: Anesthesiology Date: 2008-01 Impact factor: 7.892
Authors: Ana Fernandez-Bustamante; Soshi Hashimoto; Ary Serpa Neto; Pierre Moine; Marcos F Vidal Melo; John E Repine Journal: BMC Anesthesiol Date: 2015-05-06 Impact factor: 2.217
Authors: Marcela L Machado; Joao H N Soares; Bruno H Pypendop; Antonio J A Aguiar; Christina Braun; Gabriel C Motta-Ribeiro; Frederico C Jandre Journal: Front Vet Sci Date: 2022-05-04