STUDY PROTOCOL article
Front. Med.
Sec. Pulmonary Medicine
Point of care ultrasound-detected postoperative diaphragmatic dysfunction and its association with pulmonary complications after thoracic surgery: protocol for a prospective, observational study
Provisionally accepted
- Guangzhou Medical University Cancer Hospital, Guangzhou, China
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Introduction: Postoperative pulmonary complications (PPCs) significantly impact recovery after thoracic surgery. Postoperative diaphragmatic dysfunction (PDD) may be a key risk factor but remains under-recognized, particularly regarding comparative data between video-assisted thoracoscopic surgery (VATS) and robot-assisted thoracic surgery (RATS). This study aims to investigate the association between PDD detected by point-of-care ultrasound (POCUS) and PPCs following minimally invasive thoracic surgery. Methods: This is a single-center, prospective observational study conducted at the Affiliated Cancer Hospital of Guangzhou Medical University. A total of 148 patients scheduled for elective pulmonary resection (VATS or RATS) will be enrolled. Diaphragmatic function will be assessed using POCUS at four time points: 1 day preoperatively (T0), 30 minutes post-extubation (T1), and on postoperative day 1 (T2) and 3 (T3). The primary measurements include diaphragmatic excursion (DE) and diaphragmatic thickening fraction (DTF). The primary endpoint is the incidence of PDD (defined as DE <10 mm or negative) on postoperative day 1. Secondary endpoints include the incidence and severity of PPCs within 7 days postoperatively (defined by European Perioperative Clinical Outcome criteria), serial changes in DE and DTF, pain scores, and quality of recovery (QoR-15). Propensity score matching and multivariate regression will be used to adjust for confounders. Conclusions: This study will elucidate the relationship between POCUS-detected PDD and PPCs in patients undergoing VATS and RATS. The findings may support the integration of diaphragmatic ultrasound into perioperative risk stratification and guide targeted preventive strategies to improve postoperative outcomes.
Keywords: Diaphragm, Diaphragmatic dysfunction, Diaphragmatic ultrasound, Perioperative Period, Postoperative pulmonary complications, Thoracic Surgery, Ultrasound application, ultrasound indicators
Received: 03 Dec 2025; Accepted: 16 Feb 2026.
Copyright: © 2026 Li, Tang, Zheng and Huang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Chunlin Tang
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