Intraoperative reliability of end-tidal CO2 during elective craniotomy: Temporal changes in the PaCO2–PETCO2 gradient

Hakan Kilercik; Sacittin Taner Balcıoğlu

doi:10.18614/dehm.1939628

Intraoperative reliability of end-tidal CO2 during elective craniotomy: Temporal changes in the PaCO2–PETCO2 gradient

Abstract

Background: Precise regulation of arterial carbon dioxide tension (PaCO2) is essential in neuroanesthesia, because even minor fluctuations can directly influence cerebral perfusion and intracranial dynamics. Despite its widespread use as a non-invasive surrogate, the accuracy of end-tidal carbon dioxide (PETCO2) in reflecting arterial CO₂ is still debated. The present study aimed to evaluate the level of concordance between PaCO2 and PETCO2, and to assess temporal changes in the arterial-to-end-tidal carbon dioxide [P(a–ET)CO2] gradient during craniotomy. Methods: In this prospective observational study, 23 patients undergoing elective craniotomy were included. Simultaneous PaCO2 and PETCO2 measurements were obtained at three predefined intraoperative time points: post-induction, post-craniotomy, and at the beginning of dural closure. Temporal changes were analyzed using repeated-measures statistics, and agreement was assessed with Bland–Altman analysis. Results: PaCO2 increased significantly over time (p = 0.005), whereas PETCO2 remained stable (p = 0.376). Consequently, the P(a–ET)CO2 gradient widened significantly (p = 0.030). Bland–Altman analysis demonstrated a progressive increase in mean difference between PaCO2 and PETCO2 (from 0.89 to 2.89 mmHg), indicating reduced agreement over time. Conclusion: Our findings suggest that the P(a–ET)CO2 gradient widens over time during prolonged craniotomy, indicating that the reliability of PETCO2 as a direct substitute for PaCO2 may diminish over time. Therefore, PETCO2 should be interpreted with caution, ideally as a trend monitor rather than an absolute indicator. Periodic arterial blood gas analysis remains essential for accurate CO2 management, particularly during prolonged procedures.

Keywords

References

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Details

Primary Language

English

Subjects

Anaesthesiology

Journal Section

Research Article

Authors

Hakan Kilercik ^*
0000-0003-1624-0124
Türkiye

Sacittin Taner Balcıoğlu
0009-0000-1893-9010
Türkiye

Publication Date

July 30, 2026

Submission Date

April 28, 2026

Acceptance Date

May 22, 2026

Published in Issue

Year 2026 Volume: 40 Number: 3

DOI

https://doi.org/10.18614/dehm.1939628

IZ

https://izlik.org/JA54LH77TC

Cite

RIS / Bibtex

APA

Kilercik, H., & Balcıoğlu, S. T. (2026). Intraoperative reliability of end-tidal CO2 during elective craniotomy: Temporal changes in the PaCO2–PETCO2 gradient. Developments and Experiments in Health and Medicine, 40(3), 400-411. https://doi.org/10.18614/dehm.1939628

AMA

1.Kilercik H, Balcıoğlu ST. Intraoperative reliability of end-tidal CO2 during elective craniotomy: Temporal changes in the PaCO2–PETCO2 gradient. Dev Exp Health Med. 2026;40(3):400-411. doi:10.18614/dehm.1939628

Chicago

Kilercik, Hakan, and Sacittin Taner Balcıoğlu. 2026. “Intraoperative Reliability of End-Tidal CO2 During Elective Craniotomy: Temporal Changes in the PaCO2–PETCO2 Gradient”. Developments and Experiments in Health and Medicine 40 (3): 400-411. https://doi.org/10.18614/dehm.1939628.

EndNote

Kilercik H, Balcıoğlu ST (July 1, 2026) Intraoperative reliability of end-tidal CO2 during elective craniotomy: Temporal changes in the PaCO2–PETCO2 gradient. Developments and Experiments in Health and Medicine 40 3 400–411.

IEEE

[1]H. Kilercik and S. T. Balcıoğlu, “Intraoperative reliability of end-tidal CO2 during elective craniotomy: Temporal changes in the PaCO2–PETCO2 gradient”, Dev Exp Health Med, vol. 40, no. 3, pp. 400–411, July 2026, doi: 10.18614/dehm.1939628.

ISNAD

Kilercik, Hakan - Balcıoğlu, Sacittin Taner. “Intraoperative Reliability of End-Tidal CO2 During Elective Craniotomy: Temporal Changes in the PaCO2–PETCO2 Gradient”. Developments and Experiments in Health and Medicine 40/3 (July 1, 2026): 400-411. https://doi.org/10.18614/dehm.1939628.

JAMA

1.Kilercik H, Balcıoğlu ST. Intraoperative reliability of end-tidal CO2 during elective craniotomy: Temporal changes in the PaCO2–PETCO2 gradient. Dev Exp Health Med. 2026;40:400–411.

MLA

Kilercik, Hakan, and Sacittin Taner Balcıoğlu. “Intraoperative Reliability of End-Tidal CO2 During Elective Craniotomy: Temporal Changes in the PaCO2–PETCO2 Gradient”. Developments and Experiments in Health and Medicine, vol. 40, no. 3, July 2026, pp. 400-11, doi:10.18614/dehm.1939628.

Vancouver

1.Hakan Kilercik, Sacittin Taner Balcıoğlu. Intraoperative reliability of end-tidal CO2 during elective craniotomy: Temporal changes in the PaCO2–PETCO2 gradient. Dev Exp Health Med. 2026 Jul. 1;40(3):400-11. doi:10.18614/dehm.1939628