Dorsal Vetilation and PPCs in Colorectal Cancer Surgery Patients

Intraoperative Reduction of Ventilation of Dorsal Lung Regions and Postoperative Pulmonary Complications After Laparoscopic Colorectal Cancer Surgery

Postoperative pulmonary complications (PPCs) are common in patients after major abdominal surgery. It has been shown that 5-40% of patients occur PPCs after major surgery, and the mid to high PPC rate is observed after laparoscopic colorectal cancer surgery. PPCs are associated with poor clinical outcomes including prolonged hospital length of stay and increased morbidity and mortality.

Mechanical ventilation during general anesthesia can lead to a redistribution of ventilation, increase the aereation in the ventral parts of the lung, whereas reduce ventilation in the dorsal parts of the lung compared with spontaneous breathing (SB) in the awake state in supine position. The reduction of ventilation of dorsal lung regions indicates the presence of dorsal atelectasis during mechanical ventilation after general anesthesia, which may be associated with PPCs. However, there is still no evidence to reveal the association between the reduction of dorsal ventilation and PPCs.

Recently, electrical impedance tomography (EIT), which allows visualization of lung ventilation in real time, and assessment of regional lung ventilation. It is feasible to assess the change of ventral/dorsal lung ventilation during the surgery using EIT. To date, no study has investigated whether the change of ventral/dorsal lung ventilation revealed by EIT could be associated with PPCs.

So, this prospective observational study aims to clarify whether patients developing postoperative pulmonary complications had higher reduction of dorsal lung ventilation during operation after general anesthesia as compared to patients not developing postoperative pulmonary complications. Ratio of dorsal ventilation during spontaneous respiration (T0) in the awake state as a reference, the proportion of dorsal ventilation after anesthesia induction and endotracheal intubation (T1), body position change and capnoperitoneum (T2), and at the end of surgery (T3) were analyzed. Thereafter, evaluating the change of dorsal ventilation in patients with PPCs and without PPCs at different time points.

According to the method of sample size calculation published by Scaramuzzo G et al. (Anesthesiology. 2024 Oct 1;141(4):693-706.). A minimum sample size required for this study was calculated as following: using the difference of reduction of dorsal ventilation at the end of surgery between the patients with PPCs and non-PPCs as the primary outcome. Considering the data of our preliminary experiment showed that a reduction of dorsal lung ventilation at the end of surgery is 12 ± 6% and hypothesizing 30% of patients experiencing postoperative pulmonary complications and a relative clinically relevant increase in reduction of dorsal lung ventilation of 40% in those with postoperative pulmonary complications, we found that 83 patients were sufficient to evaluate differences between groups (effect size 0.8) with a power of 0.90 and an α error of 0.05. Considering a dropout of 10%, we found a minimum sample size of 92 patients.

Study Overview

• Status: Completed
• Conditions: Colorectal Surgery; Postoperative Pulmonary Complications (PPCs)

• Study Type: Observational
• Enrollment (Actual): 92

Contacts and Locations

Study Locations

• China
  • Zhejiang
    • Hangzhou, Zhejiang, China, 310000
      • The first Affiliated Hospital, School of Medicine, Zhejiang University.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients undergoing laparoscopic colorectal cancer surgery

Description

Inclusion Criteria:

• Age ≥18 years
• ASA grade I-III
• The patients who are planning to undergo laparoscopic colorectal cancer surgery

Exclusion Criteria:

• Emergency surgery
• Time of surgery less than 2 hours
• Preoperatively present upper respiratory tract infection or acute pulmonary infection
• Previous history of pulmonary surgery
• Preoperative use of home ventilator
• Inability to perform EIT monitoring
• Declined to participate in this study

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The difference of reduction of dorsal ventilation at the end of surgery between the patients with PPCs and non-PPCs	EIT to monitor the regional ventilation of the patients at spontaneous breathing (SB) in the awake state in supine position (T0) and the end of surgery (T3). The reduction of the ratio of dorsal ventilation will be caculated between T3 and T0.; Follow-up the patients untill discharge from the hostiptal. Based on whether pulmonary complication occurs during 7 days after surgery, the participants will be divided into the patients with PPCs and the patients with non-PPCs.; The difference of reduction of dorsal ventilation at the end of surgery (T3) between the patients with PPCs and non-PPCs will be analyzed.	1-7 days after surgery.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The risk factors which are associated with PPCs	Collecting age, gender, height, weight, history of chronic diseases such as hypertension and chronic obstructive pulmonary disease (COPD) etal, and assessing the pre-operative respiratory risk of patients using the ARISCAT (Assess Respiratory Risk in Surgical Patients in Catalonia) scoring system developed by Canet J et al.; To explore the independent risk factors which are associated with PPCs using logistic regression.	1-7 days after surgery.
The difference of reduction of dorsal ventilation at endotracheal intubation after general anesthesia induction between the patients with PPCs and non-PPCs	EIT to monitor the regional ventilation of the patients at spontaneous breathing (SB) in the awake state in supine position (T0) and endotracheal intubation after general anesthesia induction (T1). The reduction of the ratio of dorsal ventilation will be caculated between T1 and T0. 2. Follow-up the patients untill discharge from the hostiptal. Based on whether pulmonary complication occurs during 7 days after surgery, the participants will be divided into the patients with PPCs and the patients with non-PPCs. 3. The difference of reduction of dorsal ventilation at endotracheal intubation after general anesthesia induction (T1) between the patients with PPCs and non-PPCs will be analyzed.	1-7 days after surgery.
The difference of reduction of dorsal ventilation at pneumoperitoneum and body position change between the patients with PPCs and non-PPCs	EIT to monitor the regional ventilation of the patients at spontaneous breathing (SB) in the awake state in supine position (T0) and pneumoperitoneum and body position change (T2). The reduction of the ratio of dorsal ventilation will be caculated between T2 and T0. 2. Follow-up the patients untill discharge from the hostiptal. Based on whether pulmonary complication occurs during 7 days after surgery, the participants will be divided into the patients with PPCs and the patients with non-PPCs. 3. The difference of reduction of dorsal ventilation at pneumoperitoneum and body position change (T2) between the patients with PPCs and non-PPCs will be analyzed.	1-7 days after surgery.

Other Outcome Measures

Outcome Measure	Time Frame
The difference of hostpital stays between the patients with PPCs and non-PPC	From the end of surgery to the discharge from hospital, an average of 2 weeks

Collaborators and Investigators

• Sponsor: First Affiliated Hospital of Zhejiang University

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2024
• Primary Completion (Actual): December 15, 2024
• Study Completion (Actual): December 25, 2024

Study Registration Dates

• First Submitted: October 7, 2024
• First Submitted That Met QC Criteria: October 28, 2024
• First Posted (Actual): October 29, 2024

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: December 31, 2024
• Last Verified: December 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Intestinal Diseases; Gastrointestinal Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Intestinal Neoplasms; Rectal Diseases; Colonic Diseases; Colorectal Neoplasms
• Other Study ID Numbers: IIT20240443B

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No