Physiologic dead space (VD-Bohr) is the portion of the tidal volume (VT) not participating in gas exchange, composed of anatomical (VDaw) and alveolar (VDalv) dead spaces. The VD-Bohr is expressed as a ratio of the VT (VD-Bohr/VT), and the calculation requires measurement of the mixed expired (PeCO2) and mean alveolar (PaCO2) carbon dioxide, which cannot be obtained with traditional time-based capnography
monitors. Volumetric capnography (Vcap) plots expired CO2 as a function of the expired volume and provides real-time reading of PeCO2, VDaw and alveolar volume (VTalv). Furthermore, identification of the midpoint of phase III of the Vcap waveform using
mathematical models allows the determination of PaCO2 and calculation of the VD-Bohr (
Tusman et al., 2011
).To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Veterinary Anaesthesia and AnalgesiaAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- Evaluation of three tidal volumes (10, 12 and 15 mL kg-1) in dogs for controlled mechanical ventilation assessed by volumetric capnography: a randomized clinical trial.Vet Anaesth Analg. 2017; 44: 775-784
- Should we use driving pressure to set tidal volume?.Curr Opin Crit Care. 2017; 23: 38-44
- Physiologic factors influencing the arterial-to-end-tidal CO2 difference and the alveolar dead space fraction in spontaneously breathing anesthetised horses.Front Vet Sci. 2018; 5: 58
- Model fitting of volumetric capnograms improves calculations of airway dead space and slope of phase III.J Clin Monit Comput. 2009; 23: 197-206
- Validation of Bohr dead space measured by volumetric capnography.Intensive Care Med. 2011; 37: 870-874
- Reference values for volumetric capnography-derived non-invasive parameters in healthy individuals.J Clin Monit Comput. 2013; 27: 281-288
Article info
Publication history
Published online: July 03, 2022
Accepted:
June 27,
2022
Received:
February 1,
2022
Identification
Copyright
© 2022 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.
