Emmanuel Charbonney1, Stéphane Delisle2, Dominique Savary3, Gilles Bronchti4, Marceau Rigollot5, Adrien Drouet3, Bilal Badat5, Paul Ouellet6, Patrice Gosselin7, Alain Mercat8, Laurent Brochard9, Jean-Christophe M Richard10. 1. Centre de Recherche de l 'Hôpital du Sacré-cœur de Montréal, Montreal, Canada; Département de médecine, Faculté de Médecine Université de Montréal, Montreal, Canada; Laboratoire d'anatomie, Université du Québec à Trois-Rivières (UQTR) et CIUSSS MCQ, Trois-Rivières, Canada. Electronic address: emmanuel.charbonney@umontreal.ca. 2. Centre de Recherche du Centre Hospitalier Universitaire de Montréal (CHUM), Montreal, Canada. 3. SAMU74, Emergency Department, General Hospital of Annecy, Annecy, France. 4. Laboratoire d'anatomie, Université du Québec à Trois-Rivières (UQTR) et CIUSSS MCQ, Trois-Rivières, Canada. 5. Air Liquide Medical Systems, Antony, France. 6. Vitalité Health Network, North West Zone, Edmundston and Department of surgery, Université de Sherbrooke, Sherbrooke, Canada. 7. Hôpital Pierre-Le Gardeur, Terrebonne, Canada. 8. Critical Care Department, Angers University Hospital, Angers, France. 9. Keenan Centre for Biomedical Research, Li Ka Shing Knowledge Institute,St. Michael's Hospital, Toronto, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada. 10. SAMU74, Emergency Department, General Hospital of Annecy, Annecy, France; INSERM UMR 955, Créteil, France.
Abstract
BACKGROUND: Studying ventilation and intrathoracic pressure (ITP) induced by chest compressions (CC) during Cardio Pulmonary Resuscitation is challenging and important aspects such as airway closure have been mostly ignored. We hypothesized that Thiel Embalmed Cadavers could constitute an appropriate model. METHODS: We assessed respiratory mechanics and ITP during CC in 11 cadavers, and we compared it to measurements obtained in 9 out-of-hospital cardiac arrest patients and to predicted values from a bench model. An oesophageal catheter was inserted to assess chest wall compliance, and ITP variation (ΔITP). Airway pressure variation (ΔPaw) at airway opening and ΔITP generated by CC were measured at decremental positive end expiratory pressure (PEEP) to test its impact on flow and ΔPaw. The patient's data were derived from flow and airway pressure captured via the ventilator during resuscitation. RESULTS: Resistance and Compliance of the respiratory system were comparable to those of the out-of-hospital cardiac arrest patients (CRSTEC 42 ± 12 vs CRSPAT 37.3 ± 10.9 mL/cmH2O and ResTEC 17.5 ± 7.5 vs ResPAT 20.2 ± 5.3 cmH2O/L/sec), and remained stable over time. During CC, ΔITP varied from 32 ± 12 cmH2O to 69 ± 14 cmH2O with manual and automatic CC respectively. Transmission of ΔITP at the airway opening was significantly affected by PEEP, suggesting dynamic small airway closure at low lung volumes. This phenomenon was similarly observed in patients. CONCLUSION: Respiratory mechanics and dynamic pressures during CC of cadavers behave as predicted by a theoretical model and similarly to patients. The Thiel model is a suitable to assess ITP variations induced by ventilation during CC.
BACKGROUND: Studying ventilation and intrathoracic pressure (ITP) induced by chest compressions (CC) during Cardio Pulmonary Resuscitation is challenging and important aspects such as airway closure have been mostly ignored. We hypothesized that Thiel Embalmed Cadavers could constitute an appropriate model. METHODS: We assessed respiratory mechanics and ITP during CC in 11 cadavers, and we compared it to measurements obtained in 9 out-of-hospital cardiac arrestpatients and to predicted values from a bench model. An oesophageal catheter was inserted to assess chest wall compliance, and ITP variation (ΔITP). Airway pressure variation (ΔPaw) at airway opening and ΔITP generated by CC were measured at decremental positive end expiratory pressure (PEEP) to test its impact on flow and ΔPaw. The patient's data were derived from flow and airway pressure captured via the ventilator during resuscitation. RESULTS: Resistance and Compliance of the respiratory system were comparable to those of the out-of-hospital cardiac arrestpatients (CRSTEC 42 ± 12 vs CRSPAT 37.3 ± 10.9 mL/cmH2O and ResTEC 17.5 ± 7.5 vs ResPAT 20.2 ± 5.3 cmH2O/L/sec), and remained stable over time. During CC, ΔITP varied from 32 ± 12 cmH2O to 69 ± 14 cmH2O with manual and automatic CC respectively. Transmission of ΔITP at the airway opening was significantly affected by PEEP, suggesting dynamic small airway closure at low lung volumes. This phenomenon was similarly observed in patients. CONCLUSION: Respiratory mechanics and dynamic pressures during CC of cadavers behave as predicted by a theoretical model and similarly to patients. The Thiel model is a suitable to assess ITP variations induced by ventilation during CC.
Authors: Mario Suazo; Joan Herrero; Gerard Fortuny; Dolors Puigjaner; Josep M López Journal: Int J Numer Method Biomed Eng Date: 2022-02-27 Impact factor: 2.648