title: Reference values for volumetric capnography-derived non-invasive parameters in healthy individuals.
abstract: The aim of this study was to determine typical values for non-invasive volumetric capnography (VCap) parameters for healthy volunteers and anesthetized individuals. VCap was obtained by a capnograph connected to the airway opening. We prospectively studied 33 healthy volunteers 32 ± 6 years of age weighing 70 ± 13 kg at a height of 171 ± 11 cm in the supine position. Data from these volunteers were compared with a cohort of similar healthy anesthetized patients ventilated with the following settings: tidal volume (VT) of 6-8 mL/kg, respiratory rate 10-15 bpm, PEEP of 5-6 cmH₂O and FiO₂ of 0.5. Volunteers showed better clearance of CO₂ compared to anesthetized patients as indicated by (median and interquartile range): (1) an increased elimination of CO₂ per mL of VT of 0.028 (0.005) in volunteers versus 0.023 (0.003) in anesthetized patients, p < 0.05; (2) a lower normalized slope of phase III of 0.26 (0.17) in volunteers versus 0.39 (0.38) in anesthetized patients, p < 0.05; and (3) a lower Bohr dead space ratio of 0.23 (0.05) in volunteers versus 0.28 (0.05) in anesthetized patients, p < 0.05. This study presents reference values for non-invasive volumetric capnography-derived parameters in healthy individuals. Mechanical ventilation and anesthesia altered these values significantly.
authors: Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina. gtusman@hotmail.com
authors: Gerardo
authors: G
authors: Tusman
authors: Emiliano
authors: E
authors: Gogniat
authors: Stephan H
authors: SH
authors: Bohm
authors: Adriana
authors: A
authors: Scandurra
authors: Fernando
authors: F
authors: Suarez-Sipmann
authors: Agustin
authors: A
authors: Torroba
authors: Federico
authors: F
authors: Casella
authors: Sergio
authors: S
authors: Giannasi
authors: Eduardo San
authors: ES
authors: Roman
mesh_terms: D000328:Adult; D000758:Anesthesia; D019296:Capnography / Q000379:methods* / Q000706:statistics & numerical data; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods / Q000706:statistics & numerical data; D011175:Positive-Pressure Respiration; D011446:Prospective Studies; D012016:Reference Values; D012126:Respiratory Dead Space; D012189:Retrospective Studies; D013990:Tidal Volume
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