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Updated: Jul 5, 2026
08:25
Combining Volumetric Capnography And Barometric Plethysmography To Measure The Lung Structure-function Relationship
Published on: January 8, 2019
Pre and post-pulmonary thromboendarterectomies capnographic variables
Marcos Mello Moreira1, Renato Giusepe Giovani Terzi, Reinaldo Wilson Vieira
1Department of Surgery - Faculdade de Ciências Médicas da Universidade Estadual de Campinas.
Summary
This case report highlights how capnography variables like dead space fraction can aid in diagnosing pulmonary embolism (PE). These noninvasive measurements, alongside imaging, improve diagnostic accuracy for PE patients.
Area of Science:
- Respiratory Physiology
- Pulmonary Medicine
- Diagnostic Imaging
Background:
- Pulmonary embolism (PE) diagnosis relies on imaging, but noninvasive methods are sought.
- Volumetric capnography offers insights into ventilation-perfusion matching.
Observation:
- Two PE patients undergoing thromboendarterectomy were assessed using capnography and arterial blood gas analysis.
- Key capnographic variables measured included late dead space fraction (fDlate) and end-tidal alveolar dead space fraction (AVDSf).
- Pre- and post-operative values were compared, noting a false-negative fDlate in one patient.
Findings:
- Pre-operative fDlate and AVDSf were elevated in the first patient (0.16 and 0.30).
- The second patient showed a false-negative fDlate (0.01) but a positive AVDSf (0.28).
- Post-operative values normalized or improved, with fDlate becoming negative in the first patient (-0.04) and improving in the second (0.07).
Implications:
- Capnographic variables, particularly AVDSf, can be valuable noninvasive markers for PE.
- Combining capnography with imaging enhances diagnostic confidence and understanding of PE.
- This approach may offer a complementary, noninvasive tool for PE assessment.
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