Y Li1, E Tesselaar, J B Borges, S H Böhm, F Sjöberg, B Janerot-Sjöberg. 1. Department of Anesthesiology, Shaoxing People's Hospital of Zhejiang University, Shaoxing City, China; Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
Abstract
BACKGROUND: The way in which hyperoxia affects pulmonary ventilation and perfusion is not fully understood. We investigated how an increase in oxygen partial pressure in healthy young volunteers affects pulmonary ventilation and perfusion measured by thoracic electrical impedance tomography (EIT). METHODS: Twelve semi-supine healthy male volunteers aged 21-36 years were studied while breathing room air and air-oxygen mixtures (FiO2) that resulted in predetermined transcutaneous oxygen partial pressures (tcPO2) of 20, 40 and 60 kPa. The magnitude of ventilation (ΔZv) and perfusion (ΔZQ)-related changes in cyclic impedance variations, were determined using an EIT prototype equipped with 32 electrodes around the thorax. Regional changes in ventral and dorsal right lung ventilation (V) and perfusion (Q) were estimated, and V/Q ratios calculated. RESULTS: There were no significant changes in ΔZv with increasing tcPO2 levels. ΔZQ in the dorsal lung increased with increasing tcPO2 (P = 0.01), whereas no such change was seen in the ventral lung. There was a simultaneous decrease in V/Q ratio in the dorsal region during hyperoxia (P = 0.04). Two subjects did not reach a tcPO2 of 60 kPa despite breathing 100% oxygen. CONCLUSION: These results indicate that breathing increased concentrations of oxygen induces pulmonary vasodilatation in the dorsal lung even at small increases in FiO2. Ventilation remains unchanged. Local mismatch of ventilation and perfusion occurs in young healthy men, and the change in ventilation/perfusion ratio can be determined non-invasively by EIT.
BACKGROUND: The way in which hyperoxia affects pulmonary ventilation and perfusion is not fully understood. We investigated how an increase in oxygen partial pressure in healthy young volunteers affects pulmonary ventilation and perfusion measured by thoracic electrical impedance tomography (EIT). METHODS: Twelve semi-supine healthy male volunteers aged 21-36 years were studied while breathing room air and air-oxygen mixtures (FiO2) that resulted in predetermined transcutaneous oxygen partial pressures (tcPO2) of 20, 40 and 60 kPa. The magnitude of ventilation (ΔZv) and perfusion (ΔZQ)-related changes in cyclic impedance variations, were determined using an EIT prototype equipped with 32 electrodes around the thorax. Regional changes in ventral and dorsal right lung ventilation (V) and perfusion (Q) were estimated, and V/Q ratios calculated. RESULTS: There were no significant changes in ΔZv with increasing tcPO2 levels. ΔZQ in the dorsal lung increased with increasing tcPO2 (P = 0.01), whereas no such change was seen in the ventral lung. There was a simultaneous decrease in V/Q ratio in the dorsal region during hyperoxia (P = 0.04). Two subjects did not reach a tcPO2 of 60 kPa despite breathing 100% oxygen. CONCLUSION: These results indicate that breathing increased concentrations of oxygen induces pulmonary vasodilatation in the dorsal lung even at small increases in FiO2. Ventilation remains unchanged. Local mismatch of ventilation and perfusion occurs in young healthy men, and the change in ventilation/perfusion ratio can be determined non-invasively by EIT.
Authors: Hermann Körperich; Katja Müller; Peter Barth; Jürgen Gieseke; Nikolaus Haas; Ingram Schulze-Neick; Wolfgang Burchert; Deniz Kececioglu; Kai T Laser Journal: J Thorac Imaging Date: 2017-05 Impact factor: 3.000
Authors: Inéz Frerichs; Marcelo B P Amato; Anton H van Kaam; David G Tingay; Zhanqi Zhao; Bartłomiej Grychtol; Marc Bodenstein; Hervé Gagnon; Stephan H Böhm; Eckhard Teschner; Ola Stenqvist; Tommaso Mauri; Vinicius Torsani; Luigi Camporota; Andreas Schibler; Gerhard K Wolf; Diederik Gommers; Steffen Leonhardt; Andy Adler Journal: Thorax Date: 2016-09-05 Impact factor: 9.139