Validation of a method for estimating pulmonary dead space in ventilated beagles to correct exhaled propofol concentration in mixed air
Abstract Background Mixed exhaled air has been widely used to determine exhaled propofol concentrations with online analyzers, but changes in dead space proportions may lead to inaccurate assessments of critical drug concentration data. This study proposes a method to correct propofol concentration...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2025-01-01
|
| Series: | BMC Veterinary Research |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s12917-024-04458-1 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850119586942287872 |
|---|---|
| author | Xiaoxiao Li Pan Chang Xing Liu Zhongjun Zhao Yixiang Duan Wensheng Zhang |
| author_facet | Xiaoxiao Li Pan Chang Xing Liu Zhongjun Zhao Yixiang Duan Wensheng Zhang |
| author_sort | Xiaoxiao Li |
| collection | DOAJ |
| description | Abstract Background Mixed exhaled air has been widely used to determine exhaled propofol concentrations with online analyzers, but changes in dead space proportions may lead to inaccurate assessments of critical drug concentration data. This study proposes a method to correct propofol concentration in mixed air by estimating pulmonary dead space through reconstructing volumetric capnography (Vcap) from time-CO2 and time-volume curves, validated with vacuum ultraviolet time-of-flight mass spectrometry (VUV-TOF MS). Methods Existing monitoring parameters, including time-volume and time-CO2 curves, were used to determine Vcap. The ratio of physiological dead space to tidal volume (VD/VT) was calculated using Bohr’s formula. Additionally, an animal experiment on beagles was conducted with continuous propofol administration until a pseudo-steady state in exhaled propofol concentration was achieved. The propofol concentration in mixed air (CONCmix), and in alveolar air combined with N2 (CONCAN) were measured using VUV-TOF MS to calculate VD/VT. The agreements between VD/VT values from the two methods, along with the predicted CONCAN values based on Vcap and the actual measured CONCAN values were evaluated using the intraclass correlation coefficient (ICC) and Pearson correlation analysis. Results After 30 min of continuous propofol administration, a stable respiratory cycle was selected for analysis in each beagle. The calculated VD/VT-Bohr values were 0.535 for beagle A, 0.544 for beagle B, and 0.552 for beagle C. Additionally, based on CONCmix and CONCAN, the calculated VD/VT-VUV-TOF MS values were 0.494, 0.504, and 0.513, respectively. Strong agreement between the two methods was demonstrated by an ICC of 0.994 (P = 0.003) and Pearson’s r of 0.995 (P = 0.045). Additionally, the predicted CONCAN values from mixed exhaled air (5.11 parts per billion by volume (ppbv) for beagle A, 5.93 ppbv for beagle B, and 2.56 ppbv for beagle C) showed strong agreement with the actual CONCAN values, with an ICC of 0.996 (P = 0.002) and Pearson’s r of 0.994 (P = 0.046). Conclusion The physiological dead space to tidal volume ratio from mixed air in beagles can be accurately measured using the existing time-volume and time-CO2 curves from the anesthesia machine, enabling corrections of exhaled propofol concentrations in mixed air samples. |
| format | Article |
| id | doaj-art-a8e4fd9452734defae99f86ea506fb3a |
| institution | OA Journals |
| issn | 1746-6148 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Veterinary Research |
| spelling | doaj-art-a8e4fd9452734defae99f86ea506fb3a2025-08-20T02:35:36ZengBMCBMC Veterinary Research1746-61482025-01-0121111010.1186/s12917-024-04458-1Validation of a method for estimating pulmonary dead space in ventilated beagles to correct exhaled propofol concentration in mixed airXiaoxiao Li0Pan Chang1Xing Liu2Zhongjun Zhao3Yixiang Duan4Wensheng Zhang5Department of Anesthesiology, West China Hospital, Sichuan UniversityDepartment of Anesthesiology, West China Hospital, Sichuan UniversityDepartment of Anesthesiology, West China Hospital, Sichuan UniversitySchool of Mechanical Engineering, Sichuan UniversitySchool of Mechanical Engineering, Sichuan UniversityDepartment of Anesthesiology, West China Hospital, Sichuan UniversityAbstract Background Mixed exhaled air has been widely used to determine exhaled propofol concentrations with online analyzers, but changes in dead space proportions may lead to inaccurate assessments of critical drug concentration data. This study proposes a method to correct propofol concentration in mixed air by estimating pulmonary dead space through reconstructing volumetric capnography (Vcap) from time-CO2 and time-volume curves, validated with vacuum ultraviolet time-of-flight mass spectrometry (VUV-TOF MS). Methods Existing monitoring parameters, including time-volume and time-CO2 curves, were used to determine Vcap. The ratio of physiological dead space to tidal volume (VD/VT) was calculated using Bohr’s formula. Additionally, an animal experiment on beagles was conducted with continuous propofol administration until a pseudo-steady state in exhaled propofol concentration was achieved. The propofol concentration in mixed air (CONCmix), and in alveolar air combined with N2 (CONCAN) were measured using VUV-TOF MS to calculate VD/VT. The agreements between VD/VT values from the two methods, along with the predicted CONCAN values based on Vcap and the actual measured CONCAN values were evaluated using the intraclass correlation coefficient (ICC) and Pearson correlation analysis. Results After 30 min of continuous propofol administration, a stable respiratory cycle was selected for analysis in each beagle. The calculated VD/VT-Bohr values were 0.535 for beagle A, 0.544 for beagle B, and 0.552 for beagle C. Additionally, based on CONCmix and CONCAN, the calculated VD/VT-VUV-TOF MS values were 0.494, 0.504, and 0.513, respectively. Strong agreement between the two methods was demonstrated by an ICC of 0.994 (P = 0.003) and Pearson’s r of 0.995 (P = 0.045). Additionally, the predicted CONCAN values from mixed exhaled air (5.11 parts per billion by volume (ppbv) for beagle A, 5.93 ppbv for beagle B, and 2.56 ppbv for beagle C) showed strong agreement with the actual CONCAN values, with an ICC of 0.996 (P = 0.002) and Pearson’s r of 0.994 (P = 0.046). Conclusion The physiological dead space to tidal volume ratio from mixed air in beagles can be accurately measured using the existing time-volume and time-CO2 curves from the anesthesia machine, enabling corrections of exhaled propofol concentrations in mixed air samples.https://doi.org/10.1186/s12917-024-04458-1Volumetric capnographyDead spacePropofolVacuum ultraviolet time-of-flight mass spectrometryOnline analysis |
| spellingShingle | Xiaoxiao Li Pan Chang Xing Liu Zhongjun Zhao Yixiang Duan Wensheng Zhang Validation of a method for estimating pulmonary dead space in ventilated beagles to correct exhaled propofol concentration in mixed air BMC Veterinary Research Volumetric capnography Dead space Propofol Vacuum ultraviolet time-of-flight mass spectrometry Online analysis |
| title | Validation of a method for estimating pulmonary dead space in ventilated beagles to correct exhaled propofol concentration in mixed air |
| title_full | Validation of a method for estimating pulmonary dead space in ventilated beagles to correct exhaled propofol concentration in mixed air |
| title_fullStr | Validation of a method for estimating pulmonary dead space in ventilated beagles to correct exhaled propofol concentration in mixed air |
| title_full_unstemmed | Validation of a method for estimating pulmonary dead space in ventilated beagles to correct exhaled propofol concentration in mixed air |
| title_short | Validation of a method for estimating pulmonary dead space in ventilated beagles to correct exhaled propofol concentration in mixed air |
| title_sort | validation of a method for estimating pulmonary dead space in ventilated beagles to correct exhaled propofol concentration in mixed air |
| topic | Volumetric capnography Dead space Propofol Vacuum ultraviolet time-of-flight mass spectrometry Online analysis |
| url | https://doi.org/10.1186/s12917-024-04458-1 |
| work_keys_str_mv | AT xiaoxiaoli validationofamethodforestimatingpulmonarydeadspaceinventilatedbeaglestocorrectexhaledpropofolconcentrationinmixedair AT panchang validationofamethodforestimatingpulmonarydeadspaceinventilatedbeaglestocorrectexhaledpropofolconcentrationinmixedair AT xingliu validationofamethodforestimatingpulmonarydeadspaceinventilatedbeaglestocorrectexhaledpropofolconcentrationinmixedair AT zhongjunzhao validationofamethodforestimatingpulmonarydeadspaceinventilatedbeaglestocorrectexhaledpropofolconcentrationinmixedair AT yixiangduan validationofamethodforestimatingpulmonarydeadspaceinventilatedbeaglestocorrectexhaledpropofolconcentrationinmixedair AT wenshengzhang validationofamethodforestimatingpulmonarydeadspaceinventilatedbeaglestocorrectexhaledpropofolconcentrationinmixedair |