Effects of changes in inspired oxygen fraction on urinary oxygen tension measurements
Abstract Background Continuous measurement of urinary PO2 (PuO2) is being applied to indirectly monitor renal medullary PO2. However, when applied to critically ill patients with shock, its measurement may be affected by changes in FiO2 and PaO2 and potential associated O2 diffusion between urine an...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2022-12-01
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| Series: | Intensive Care Medicine Experimental |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s40635-022-00479-y |
| _version_ | 1797980530013110272 |
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| author | Eduardo A. Osawa Salvatore L. Cutuli Fumitaka Yanase Naoya Iguchi Laurent Bitker Alexandre T. Maciel Yugeesh R. Lankadeva Clive N. May Roger G. Evans Glenn M. Eastwood Rinaldo Bellomo |
| author_facet | Eduardo A. Osawa Salvatore L. Cutuli Fumitaka Yanase Naoya Iguchi Laurent Bitker Alexandre T. Maciel Yugeesh R. Lankadeva Clive N. May Roger G. Evans Glenn M. Eastwood Rinaldo Bellomo |
| author_sort | Eduardo A. Osawa |
| collection | DOAJ |
| description | Abstract Background Continuous measurement of urinary PO2 (PuO2) is being applied to indirectly monitor renal medullary PO2. However, when applied to critically ill patients with shock, its measurement may be affected by changes in FiO2 and PaO2 and potential associated O2 diffusion between urine and ureteric or bladder tissue. We aimed to investigate PuO2 measurements in septic shock patients with a fiberoptic luminescence optode inserted into the urinary catheter lumen in relation to episodes of FiO2 change. We also evaluated medullary and urinary oxygen tension values in Merino ewes at two different FiO2 levels. Results In 10 human patients, there were 32 FiO2 decreases and 31 increases in FiO2. Median pre-decrease FiO2 was 0.36 [0.30, 0.39] and median post-decrease FiO2 was 0.30 [0.23, 0.30], p = 0.006. PaO2 levels decreased from 83 mmHg [77, 94] to 72 [62, 80] mmHg, p = 0.009. However, PuO2 was 23.2 mmHg [20.5, 29.0] before and 24.2 mmHg [20.6, 26.3] after the intervention (p = 0.56). The median pre-increase FiO2 was 0.30 [0.21, 0.30] and median post-increase FiO2 was 0.35 [0.30, 0.40], p = 0.008. PaO2 levels increased from 64 mmHg [58, 72 mmHg] to 71 mmHg [70, 100], p = 0.04. However, PuO2 was 25.0 mmHg [IQR: 20.7, 26.8] before and 24.3 mmHg [IQR: 20.7, 26.3] after the intervention (p = 0.65). A mixed linear regression model showed a weak correlation between the variation in PaO2 and the variation in PuO2 values. In 9 Merino ewes, when comparing oxygen tension levels between FiO2 of 0.21 and 0.40, medullary values did not differ (25.1 ± 13.4 mmHg vs. 27.9 ± 15.4 mmHg, respectively, p = 0.6766) and this was similar to urinary oxygen values (27.1 ± 6.17 mmHg vs. 29.7 ± 4.41 mmHg, respectively, p = 0.3192). Conclusions Changes in FiO2 and PaO2 within the context of usual care did not affect PuO2. Our findings were supported by experimental data and suggest that PuO2 can be used as biomarker of medullary oxygenation irrespective of FiO2. |
| first_indexed | 2024-04-11T05:55:39Z |
| format | Article |
| id | doaj.art-9bd76ef9856144bca988e6424936d46b |
| institution | Directory Open Access Journal |
| issn | 2197-425X |
| language | English |
| last_indexed | 2024-04-11T05:55:39Z |
| publishDate | 2022-12-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Intensive Care Medicine Experimental |
| spelling | doaj.art-9bd76ef9856144bca988e6424936d46b2022-12-22T04:41:54ZengSpringerOpenIntensive Care Medicine Experimental2197-425X2022-12-0110111410.1186/s40635-022-00479-yEffects of changes in inspired oxygen fraction on urinary oxygen tension measurementsEduardo A. Osawa0Salvatore L. Cutuli1Fumitaka Yanase2Naoya Iguchi3Laurent Bitker4Alexandre T. Maciel5Yugeesh R. Lankadeva6Clive N. May7Roger G. Evans8Glenn M. Eastwood9Rinaldo Bellomo10Imed Group Research DepartmentDipartimento di Scienze dell’Emergenza, Anestesiologiche e della Rianimazione, Fondazione Policlinico Universitario A. Gemelli IRCCSDepartment of Intensive Care, Austin HospitalDepartment of Intensive Care, Austin HospitalService de Médecine Intensive – Réanimation, Hôpital de La Croix Rousse, Hospices Civils de LyonImed Group Research DepartmentPre-Clinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of MelbournePre-Clinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of MelbournePre-Clinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of MelbourneDepartment of Intensive Care, Austin HospitalDepartment of Intensive Care, Austin HospitalAbstract Background Continuous measurement of urinary PO2 (PuO2) is being applied to indirectly monitor renal medullary PO2. However, when applied to critically ill patients with shock, its measurement may be affected by changes in FiO2 and PaO2 and potential associated O2 diffusion between urine and ureteric or bladder tissue. We aimed to investigate PuO2 measurements in septic shock patients with a fiberoptic luminescence optode inserted into the urinary catheter lumen in relation to episodes of FiO2 change. We also evaluated medullary and urinary oxygen tension values in Merino ewes at two different FiO2 levels. Results In 10 human patients, there were 32 FiO2 decreases and 31 increases in FiO2. Median pre-decrease FiO2 was 0.36 [0.30, 0.39] and median post-decrease FiO2 was 0.30 [0.23, 0.30], p = 0.006. PaO2 levels decreased from 83 mmHg [77, 94] to 72 [62, 80] mmHg, p = 0.009. However, PuO2 was 23.2 mmHg [20.5, 29.0] before and 24.2 mmHg [20.6, 26.3] after the intervention (p = 0.56). The median pre-increase FiO2 was 0.30 [0.21, 0.30] and median post-increase FiO2 was 0.35 [0.30, 0.40], p = 0.008. PaO2 levels increased from 64 mmHg [58, 72 mmHg] to 71 mmHg [70, 100], p = 0.04. However, PuO2 was 25.0 mmHg [IQR: 20.7, 26.8] before and 24.3 mmHg [IQR: 20.7, 26.3] after the intervention (p = 0.65). A mixed linear regression model showed a weak correlation between the variation in PaO2 and the variation in PuO2 values. In 9 Merino ewes, when comparing oxygen tension levels between FiO2 of 0.21 and 0.40, medullary values did not differ (25.1 ± 13.4 mmHg vs. 27.9 ± 15.4 mmHg, respectively, p = 0.6766) and this was similar to urinary oxygen values (27.1 ± 6.17 mmHg vs. 29.7 ± 4.41 mmHg, respectively, p = 0.3192). Conclusions Changes in FiO2 and PaO2 within the context of usual care did not affect PuO2. Our findings were supported by experimental data and suggest that PuO2 can be used as biomarker of medullary oxygenation irrespective of FiO2.https://doi.org/10.1186/s40635-022-00479-yInspired oxygen fractionSepsisSeptic shockUrinary oxygen tensionUrinary oxygenation |
| spellingShingle | Eduardo A. Osawa Salvatore L. Cutuli Fumitaka Yanase Naoya Iguchi Laurent Bitker Alexandre T. Maciel Yugeesh R. Lankadeva Clive N. May Roger G. Evans Glenn M. Eastwood Rinaldo Bellomo Effects of changes in inspired oxygen fraction on urinary oxygen tension measurements Intensive Care Medicine Experimental Inspired oxygen fraction Sepsis Septic shock Urinary oxygen tension Urinary oxygenation |
| title | Effects of changes in inspired oxygen fraction on urinary oxygen tension measurements |
| title_full | Effects of changes in inspired oxygen fraction on urinary oxygen tension measurements |
| title_fullStr | Effects of changes in inspired oxygen fraction on urinary oxygen tension measurements |
| title_full_unstemmed | Effects of changes in inspired oxygen fraction on urinary oxygen tension measurements |
| title_short | Effects of changes in inspired oxygen fraction on urinary oxygen tension measurements |
| title_sort | effects of changes in inspired oxygen fraction on urinary oxygen tension measurements |
| topic | Inspired oxygen fraction Sepsis Septic shock Urinary oxygen tension Urinary oxygenation |
| url | https://doi.org/10.1186/s40635-022-00479-y |
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