Higher intraoperative arterial-to-end-tidal carbon dioxide gradients are associated with postoperative respiratory morbidity after lung cancer resection: a retrospective INSPIRE cohort study
- 1The Second Affiliated Hospital of Bengbu Medical University , ,
Abstract
Background
The arterial-to-end-tidal carbon dioxide gradient may reflect impaired gas exchange during thoracic surgery. We examined its association with postoperative respiratory morbidity after lung cancer resection.Methods
We conducted a retrospective cohort study using INSPIRE version 1.4.2. Each intraoperative arterial carbon dioxide (PaCO₂) measurement was paired with the nearest positive end-tidal carbon dioxide (EtCO₂) measurement within 10 min, and the primary exposure was each patient's median gradient. Respiratory morbidity was defined from new respiratory diagnoses and qualifying postoperative ventilation records during the index admission. We used multivariable regression, repeated-measurement analyses, sensitivity analyses, and exploratory internally validated prediction models.Results
Among 2,665 eligible patients, 85 (3.2%) had respiratory morbidity. A valid gradient was available in 2,527 patients; the primary complete-case analysis included 2,436 patients and 80 events. Each 5 mmHg higher gradient was associated with greater morbidity (adjusted odds ratio 1.53, 95% confidence interval 1.17-2.00; adjusted risk ratio 1.48, 1.14-1.91). Standardised risk increased from 2.28% at the first gradient quartile to 3.46% at the third, a difference of 1.18 percentage points (0.49-1.83). In a post hoc comparison, adding the gradient to a model already containing PaCO₂ and clinical covariates did not materially change internally cross-validated discrimination (AUROC 0.7324 vs. 0.7325).Conclusion
A higher intraoperative PaCO₂-EtCO₂ gradient was associated with postoperative respiratory morbidity after lung cancer resection, but its incremental prognostic value beyond PaCO₂ was limited in exploratory analyses. Prospective external validation is required before clinical use.
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BibTeX
@article{li2026higher,
title = {{Higher intraoperative arterial-to-end-tidal carbon dioxide gradients are associated with postoperative respiratory morbidity after lung cancer resection: a retrospective INSPIRE cohort study}},
author = {Long Li and Dan Wang and Qingyi Zhou and Bin Shang},
journal = {Frontiers in medicine},
year = {2026},
month = oct,
doi = {10.3389/fmed.2026.1995794},
url = {https://europepmc.org/article/PMC/PMC13716742},
note = {CC BY},
}
RIS
TY - JOUR
TI - Higher intraoperative arterial-to-end-tidal carbon dioxide gradients are associated with postoperative respiratory morbidity after lung cancer resection: a retrospective INSPIRE cohort study
AU - Long Li
AU - Dan Wang
AU - Qingyi Zhou
AU - Bin Shang
PY - 2026
DA - 2026/10/15
JO - Frontiers in medicine
DO - 10.3389/fmed.2026.1995794
UR - https://europepmc.org/article/PMC/PMC13716742
AB - Background The arterial-to-end-tidal carbon dioxide gradient may reflect impaired gas exchange during thoracic surgery. We examined its association with postoperative respiratory morbidity after lung cancer resection.Methods We conducted a retrospective cohort study using INSPIRE version 1.4.2. Each intraoperative arterial carbon dioxide (PaCO₂) measurement was paired with the nearest positive end-tidal carbon dioxide (EtCO₂) measurement within 10 min, and the primary exposure was each patient's median gradient. Respiratory morbidity was defined from new respiratory diagnoses and qualifying postoperative ventilation records during the index admission. We used multivariable regression, repeated-measurement analyses, sensitivity analyses, and exploratory internally validated prediction models.Results Among 2,665 eligible patients, 85 (3.2%) had respiratory morbidity. A valid gradient was available in 2,527 patients; the primary complete-case analysis included 2,436 patients and 80 events. Each 5 mmHg higher gradient was associated with greater morbidity (adjusted odds ratio 1.53, 95% confidence interval 1.17-2.00; adjusted risk ratio 1.48, 1.14-1.91). Standardised risk increased from 2.28% at the first gradient quartile to 3.46% at the third, a difference of 1.18 percentage points (0.49-1.83). In a post hoc comparison, adding the gradient to a model already containing PaCO₂ and clinical covariates did not materially change internally cross-validated discrimination (AUROC 0.7324 vs. 0.7325).Conclusion A higher intraoperative PaCO₂-EtCO₂ gradient was associated with postoperative respiratory morbidity after lung cancer resection, but its incremental prognostic value beyond PaCO₂ was limited in exploratory analyses. Prospective external validation is required before clinical use.
SN - 2296-858X
ER -