Effects of changes in trunk inclination on ventilatory efficiency in ARDS patients: quasi-experimental study

Intensive Care Medicine Experimental

Research Articles

David Torres¹  Jaime Retamal²  María C. Bachmann³  Leonardo Soto⁴  Jorge Dreyse⁵  Francisco Labbe⁵  Fabian Poblete⁵  Martín H. Benites⁶  Andrés Ferre⁷  Tomas E. Regueira⁸ 

[1] Departamento de Epidemiología y Estudios en Salud, Magíster en Epidemiología, Universidad de los Andes, Monseñor Álvaro del Portillo 12455, Santiago, Chile;Departamento de Medicina Intensiva, Hospital Clínico Pontificia Universidad Católica de Chile, Marcoleta 367, Santiago, Chile;Estudiante del Programa Doctorado en Ciencias Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O’Higgins 340, Santiago, Chile;Departamento de Medicina Intensiva, Hospital Clínico Pontificia Universidad Católica de Chile, Marcoleta 367, Santiago, Chile;Facultad de Medicina, Escuela de Medicina, Universidad Finis Terrae, Av. Pedro de Valdivia 1509, Santiago, Chile;Unidad de Pacientes Críticos, Clínica Santa María, Bellavista 415, Santiago, Chile;Unidad de Pacientes Críticos, Clínica Las Condes, Estoril 450, Santiago, Chile;Unidad de Pacientes Críticos, Clínica Las Condes, Estoril 450, Santiago, Chile;Departamento de Epidemiología y Estudios en Salud, Magíster en Epidemiología, Universidad de los Andes, Monseñor Álvaro del Portillo 12455, Santiago, Chile;Estudiante del Programa Doctorado en Ciencias Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O’Higgins 340, Santiago, Chile;Facultad de Medicina, Escuela de Medicina, Universidad Finis Terrae, Av. Pedro de Valdivia 1509, Santiago, Chile;Unidad de Pacientes Críticos, Clínica Las Condes, Estoril 450, Santiago, Chile;Facultad de Medicina, Escuela de Medicina, Universidad Finis Terrae, Av. Pedro de Valdivia 1509, Santiago, Chile;Unidad de Pacientes Críticos, Clínica Santa María, Bellavista 415, Santiago, Chile;

关键词: Acute respiratory distress syndrome;    Body position;    Respiratory dead space;    Tidal volume;   

DOI  :  10.1186/s40635-023-00550-2

 received in 2023-04-12, accepted in 2023-09-12,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundTrunk inclination from semirecumbent head-upright to supine-flat positioning reduces driving pressure and increases respiratory system compliance in patients with acute respiratory distress syndrome (ARDS). These effects are associated with an improved ventilatory ratio and reduction in the partial pressure of carbon dioxide (PaCO2). However, these physiological effects have not been completely studied, and their mechanisms have not yet been elucidated. Therefore, this study aimed to evaluate the effects of a change in trunk inclination from semirecumbent (45°) to supine-flat (10°) on physiological dead space and ventilation distribution in different lung regions.ResultsTwenty-two ARDS patients on pressure-controlled ventilation underwent three 60-min steps in which trunk inclination was changed from 45° (baseline) to 10° (intervention) and back to 45° (control) in the last step. Tunk inclination from a semirecumbent (45°) to a supine-flat (10°) position resulted in a higher tidal volume [371 (± 76) vs. 433 (± 84) mL (P < 0.001)] and respiratory system compliance [34 (± 10) to 41 (± 12) mL/cmH2O (P < 0.001)]. The CO2 exhaled per minute improved from 191 mL/min (± 34) to 227 mL/min (± 38) (P < 0.001). Accordingly, Bohr’s dead space ratio decreased from 0.49 (± 0.07) to 0.41 (± 0.06) (p < 0.001), and PaCO2 decreased from 43 (± 5) to 36 (± 4) mmHg (p < 0.001). In addition, the impedance ratio, which divides the ventilation activity of the ventral region by the dorsal region ventilation activity in tidal images, dropped from 1.27 (0.83–1.78) to 0.86 (0.51–1.33) (p < 0.001). These results, calculated from functional EIT images, indicated further ventilation activity in the dorsal lung regions. These effects rapidly reversed once the patient was repositioned at 45°.ConclusionsA change in trunk inclination from a semirecumbent (45 degrees) to a supine-flat position (10 degrees) improved Bohr’s dead space ratio and reduced PaCO2 in patients with ARDS. This effect is associated with an increase in tidal volume and respiratory system compliance, along with further favourable impedance ventilation distribution toward the dorsal lung regions. This study highlights the importance of considering trunk inclination as a modifiable determinant of physiological parameters. The angle of trunk inclination is essential information that must be reported in ARDS patients.

【 授权许可】

CC BY   
© European Society of Intensive Care Medicine and Springer Nature Switzerland AG 2023

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