Li CP, Lv YM. Carbon dioxide embolism during salvage transanal total mesorectal excision in “frozen pelvis”: Two case reports. World J Gastrointest Surg 2026; 18(7): 119733 [DOI: 10.4240/wjgs.v18.i7.119733]
Corresponding Author of This Article
Yi-Ming Lv, MD, Department of Colorectal Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, No. 3 Qingchun Road, Shangcheng District, Hangzhou 310016, Zhejiang Province, China. elliottlv@zju.edu.cn
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Surgery
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case-report
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Li CP, Lv YM. Carbon dioxide embolism during salvage transanal total mesorectal excision in “frozen pelvis”: Two case reports. World J Gastrointest Surg 2026; 18(7): 119733 [DOI: 10.4240/wjgs.v18.i7.119733]
World J Gastrointest Surg. Jul 27, 2026; 18(7): 119733 Published online Jul 27, 2026. doi: 10.4240/wjgs.v18.i7.119733
Carbon dioxide embolism during salvage transanal total mesorectal excision in “frozen pelvis”: Two case reports
Cai-Ping Li, Yi-Ming Lv
Cai-Ping Li, Department of Nursing, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, Zhejiang Province, China
Yi-Ming Lv, Department of Colorectal Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, Zhejiang Province, China
Author contributions: Li CP was responsible for the perioperative nursing care of the patients and data acquisition; Lv YM was responsible for the conceptualization, data analysis, and drafting of the manuscript. Both authors read and approved the final manuscript.
AI contribution statement: Gemini 3.1 Pro was used during the preparation of this manuscript. Gemini 3.1 Pro was used for writing assistance, translation support, and language polishing of the Abstract and Discussion sections. Portions of the Abstract and Discussion sections were drafted with the assistance of Gemini 3.1 Pro based strictly on the authors’ original clinical inputs, study data, and conceptual framework. No scientific content, factual clinical data, statistical results, or conclusions were autonomously generated by the AI tool. It was not used for statistical analysis or data analysis. Figure 2 was generated with the assistance of Google Nano Banana Pro based on author-provided conceptual instructions. The figure is used solely as a schematic medical illustration. It does not contain patient-identifiable information, original clinical images, radiological images, pathological images, experimental data, or raw research data. The anatomical and clinical content of the figure was reviewed and verified by the authors. We confirm that all clinical data, statistical results, scientific interpretations, and final conclusions presented in the manuscript were generated, reviewed, and approved by the authors.
Informed consent statement: An informed written consent was obtained from the patients for the publication of this report and any accompanying images.
Conflict-of-interest statement: The authors declare that they have no conflicts of interest to disclose.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Corresponding author: Yi-Ming Lv, MD, Department of Colorectal Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, No. 3 Qingchun Road, Shangcheng District, Hangzhou 310016, Zhejiang Province, China. elliottlv@zju.edu.cn
Received: February 7, 2026 Revised: March 9, 2026 Accepted: March 23, 2026 Published online: July 27, 2026 Processing time: 172 Days and 7.8 Hours
Abstract
BACKGROUND
Transanal total mesorectal excision (TaTME) is increasingly used for salvage surgery in local rectal cancer recurrence. However, the fibrotic “frozen pelvis” presents a unique physiological hazard. We report two cases of massive carbon dioxide (CO2) embolism that occurred during salvage TaTME, highlighting the mechanism of “non-collapsible veins” and a specific capnographic diagnostic pattern.
CASE SUMMARY
Two male patients (64 years old and 68 years old, respectively) underwent salvage TaTME for recurrent rectal cancer. Both procedures utilized a simultaneous two-team approach with standard 15 mmHg insufflation. During deep pelvic dissection within the fibrotic field, both patients experienced sudden hemodynamic collapse (severe hypotension in case 1 and asystole in case 2). A distinct biphasic capnographic pattern was observed in both scenarios: An initial precipitous drop in end-tidal CO2 marking the embolic event, followed by a rapid paradoxical surge (> 50 mmHg) during resuscitation. This “rebound hypercapnia” confirmed the massive systemic CO2 absorption. Immediate cessation of insufflation, fluid resuscitation, and conversion to open surgery were performed. One patient recovered without sequelae, while the other patient achieved return of spontaneous circulation after cardiopulmonary resuscitation.
CONCLUSION
Enhanced vigilance for CO2 embolism is strongly advised in the “frozen pelvis”. The biphasic capnographic signature can serve as a critical observational point for early recognition, and a rapid multidisciplinary response involving the nursing team is essential for patient survival.
Core Tip: This case series serves as a critical warning on the significant intraoperative hazard of salvage transanal total mesorectal excision: Dense fibrosis resulting from prior multimodality treatment creates “non-collapsible veins” that remain open when injured, allowing massive carbon dioxide (CO2) influx. The investigators highlight the diagnostic biphasic capnographic signature-initial hypocapnia followed by rebound hypercapnia-as a key observational point for differentiating CO2 embolism from other causes of intraoperative collapse, and emphasize the vital role of perioperative nursing collaboration in the successful management of such crises.
