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Yoshida T, Nakahashi S, Nakamura MAM, Koyama Y, Roldan R, Torsani V, De Santis RR, Gomes S, Uchiyama A, Amato MBP, Kavanagh BP, Fujino Y. Volume-controlled Ventilation Does Not Prevent Injurious Inflation during Spontaneous Effort. Am J Respir Crit Care Med 2017; 196:590-601. [PMID: 28212050 DOI: 10.1164/rccm.201610-1972oc] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
RATIONALE Spontaneous breathing during mechanical ventilation increases transpulmonary pressure and Vt, and worsens lung injury. Intuitively, controlling Vt and transpulmonary pressure might limit injury caused by added spontaneous effort. OBJECTIVES To test the hypothesis that, during spontaneous effort in injured lungs, limitation of Vt and transpulmonary pressure by volume-controlled ventilation results in less injurious patterns of inflation. METHODS Dynamic computed tomography was used to determine patterns of regional inflation in rabbits with injured lungs during volume-controlled or pressure-controlled ventilation. Transpulmonary pressure was estimated by using esophageal balloon manometry [Pl(es)] with and without spontaneous effort. Local dependent lung stress was estimated as the swing (inspiratory change) in transpulmonary pressure measured by intrapleural manometry in dependent lung and was compared with the swing in Pl(es). Electrical impedance tomography was performed to evaluate the inflation pattern in a larger animal (pig) and in a patient with acute respiratory distress syndrome. MEASUREMENTS AND MAIN RESULTS Spontaneous breathing in injured lungs increased Pl(es) during pressure-controlled (but not volume-controlled) ventilation, but the pattern of dependent lung inflation was the same in both modes. In volume-controlled ventilation, spontaneous effort caused greater inflation and tidal recruitment of dorsal regions (greater than twofold) compared with during muscle paralysis, despite the same Vt and Pl(es). This was caused by higher local dependent lung stress (measured by intrapleural manometry). In injured lungs, esophageal manometry underestimated local dependent pleural pressure changes during spontaneous effort. CONCLUSIONS Limitation of Vt and Pl(es) by volume-controlled ventilation could not eliminate harm caused by spontaneous breathing unless the level of spontaneous effort was lowered and local dependent lung stress was reduced.
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Affiliation(s)
- Takeshi Yoshida
- 1 Intensive Care Unit, Osaka University Hospital, Suita, Japan.,2 Translational Medicine, Department of Critical Care Medicine and Department of Anesthesia, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Susumu Nakahashi
- 1 Intensive Care Unit, Osaka University Hospital, Suita, Japan.,3 Emergency and Critical Care Center, Mie University Hospital, Tsu, Japan
| | - Maria Aparecida Miyuki Nakamura
- 4 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Instituto do Coração (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and
| | - Yukiko Koyama
- 1 Intensive Care Unit, Osaka University Hospital, Suita, Japan
| | - Rollin Roldan
- 4 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Instituto do Coração (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and.,5 Unidad de Cuidados Intensivos, Hospital Rebagliati, Lima, Peru
| | - Vinicius Torsani
- 4 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Instituto do Coração (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and
| | - Roberta R De Santis
- 4 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Instituto do Coração (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and
| | - Susimeire Gomes
- 4 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Instituto do Coração (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and
| | | | - Marcelo B P Amato
- 4 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Instituto do Coração (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and
| | - Brian P Kavanagh
- 2 Translational Medicine, Department of Critical Care Medicine and Department of Anesthesia, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Yuji Fujino
- 1 Intensive Care Unit, Osaka University Hospital, Suita, Japan
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Mauri T, Cambiaghi B, Spinelli E, Langer T, Grasselli G. Spontaneous breathing: a double-edged sword to handle with care. ANNALS OF TRANSLATIONAL MEDICINE 2017; 5:292. [PMID: 28828367 DOI: 10.21037/atm.2017.06.55] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In acute hypoxemic respiratory failure (AHRF) and acute respiratory distress syndrome (ARDS) patients, spontaneous breathing is associated with multiple physiologic benefits: it prevents muscles atrophy, avoids paralysis, decreases sedation needs and is associated with improved hemodynamics. On the other hand, in the presence of uncontrolled inspiratory effort, severe lung injury and asynchronies, spontaneous ventilation might also worsen lung edema, induce diaphragm dysfunction and lead to muscles exhaustion and prolonged weaning. In the present review article, we present physiologic mechanisms driving spontaneous breathing, with emphasis on how to implement basic and advanced respiratory monitoring to assess lung protection during spontaneous assisted ventilation. Then, key benefits and risks associated with spontaneous ventilation are described. Finally, we propose some clinical means to promote protective spontaneous breathing at the bedside. In summary, early switch to spontaneous assisted breathing of acutely hypoxemic patients is more respectful of physiology and might yield several advantages. Nonetheless, risk of additional lung injury is not completely avoided during spontaneous breathing and careful monitoring of target physiologic variables such as tidal volume (Vt) and driving transpulmonary pressure should be applied routinely. In clinical practice, multiple interventions such as extracorporeal CO2 removal exist to maintain inspiratory effort, Vt and driving transpulmonary pressure within safe limits but more studies are needed to assess their long-term efficacy.
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Affiliation(s)
- Tommaso Mauri
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy.,Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Barbara Cambiaghi
- Department of Medicine and Surgery, University of Milan-Bicocca, Monza, Italy
| | - Elena Spinelli
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Thomas Langer
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Giacomo Grasselli
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy.,Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
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