"Liuzijue" Qigong training enhances early pulmonary function recovery after esophageal cancer surgery

Abstract

BACKGROUND

Esophageal cancer surgery is associated with a high risk of postoperative pulmonary complications, particularly pneumonia. Although conventional respiratory rehabilitation strategies – such as preoperative inspiratory muscle training – have demonstrated limited efficacy, the low-intensity traditional Chinese Qigong practice "Liuzijue" (Six-Character Formula) shows promise. However, robust clinical evidence supporting its use in patients undergoing esophagectomy remains lacking.

AIM

To evaluate the effects of early postoperative "Liuzijue" training on pulmonary function and pneumonia incidence following radical esophagectomy.

METHODS

This retrospective study included 306 patients who underwent esophagectomy. The control group (n = 163) received standard care, consisting of abdominal breathing, incentive spirometry, and early ambulation. The intervention group (n = 143) received the same standard care plus twice-daily "Liuzijue" training for 14 days. Primary outcomes were the incidence of pneumonia (defined by Centers for Disease Control and Prevention criteria) and changes (Δ) in forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), and maximum voluntary ventilation (MVV) from baseline to postoperative day 14.

RESULTS

The "Liuzijue" intervention was associated with a significantly lower incidence of pneumonia (11.9% vs 24.5%, P = 0.005; relative risk = 0.48). Significant improvements were observed in ΔFVC (+502.1 mL vs +326.5 mL, P < 0.001), ΔFEV₁ (+701.7 mL vs +434.4 mL, P < 0.001), and ΔMVV (+19.4 L/minute vs +14.4 L/minute, P < 0.001). Absolute FEV₁ values on postoperative day 14 were higher in the intervention group (2270.8 mL vs 2066.1 mL, P = 0.021), along with significantly lower Borg dyspnea/fatigue scores (P = 0.045). No significant differences were observed in changes in diffusing capacity of the lung for carbon monoxide, total lung capacity, or 6-minute walk distance.

CONCLUSION

Early initiation of "Liuzijue" training after esophagectomy is associated with reduced pneumonia incidence and accelerated recovery of key pulmonary function parameters. These findings support the integration of "Liuzijue" into enhanced recovery after surgery protocols for esophageal cancer patients.

Key Words: Esophagectomy; Postoperative pulmonary complications; Pulmonary function; Enhanced recovery after surgery; "Liuzijue" Qigong

Core Tip: Early postoperative "Liuzijue" Qigong training significantly reduces the risk of postoperative pneumonia and accelerates the recovery of core pulmonary function parameters in patients undergoing radical esophagectomy. As a low-intensity intervention, it integrates coordinated breathing techniques with vocalization to enhance postoperative respiratory muscle function. This approach is particularly well-suited for incorporation into enhanced recovery after surgery pathways, offering a safe, feasible, and effective adjunct to conventional respiratory rehabilitation strategies.

INTRODUCTION

Esophageal cancer, a highly aggressive malignancy of the digestive tract, has shown a steadily increasing global incidence in recent years, particularly in specific high-risk regions[1]. According to global statistics, it ranks as the seventh leading cause of cancer-related death worldwide, imposing substantial physical and psychological burdens on patients and placing significant economic strain on healthcare systems[2]. Currently, surgical resection combined with radiotherapy and chemotherapy constitutes the primary treatment approach for esophageal cancer. Although these modalities have improved survival outcomes, the rate of postoperative complications remains high. Among them, respiratory complications – such as pneumonia and atelectasis – are especially common and are major contributors to intensive care unit readmission and increased mortality[3]. Therefore, identifying effective postoperative rehabilitation strategies, particularly those targeting pulmonary function recovery, is critically important.

Conventional rehabilitation approaches have notable limitations. While preoperative inspiratory muscle training (IMT) has been widely studied, its effectiveness in patients undergoing esophagectomy remains controversial and lacks specificity for early postoperative respiratory recovery[4-6]. In recent years, fast-track surgery-based respiratory interventions – such as diaphragmatic breathing and incentive spirometry – have demonstrated benefits in promoting lung function recovery. However, these methods often require equipment or intense patient effort, potentially limiting adherence and tolerance during the early postoperative period[7]. Under these circumstances, the traditional Chinese Qigong practice known as "Liuzijue" (Six-Character Formula) has emerged as a promising low-intensity intervention. By integrating specific vocalizations (Xu, He, Hu, Xi, Chui, Si) with coordinated respiratory movements, "Liuzijue" effectively regulates breathing patterns, enhances diaphragmatic activity, and facilitates sputum clearance[8]. Despite its potential, the application of "Liuzijue" in postoperative management of esophageal cancer remains underdeveloped and insufficiently systematized. Most existing studies focus on chronic respiratory diseases – such as chronic obstructive pulmonary disease (COPD) – or neurological rehabilitation, with a marked lack of high-quality randomized controlled trials (RCTs) evaluating its efficacy in enhancing pulmonary recovery after esophagectomy. Notably, evidence regarding its impact during the critical early postoperative phase (within two weeks) remains limited[9,10].

This study aims to address this research gap through a single-center retrospective analysis to investigate, for the first time, the effects of early postoperative "Liuzijue" training on key pulmonary function parameters – forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and maximum voluntary ventilation (MVV) – and on the incidence of postoperative pneumonia within the first two weeks following esophagectomy. It further seeks to compare its efficacy with that of conventional rehabilitation strategies. By doing so, this research intends to provide evidence-based support for respiratory rehabilitation in esophageal cancer patients, promote the integration of "Liuzijue" into enhanced recovery after surgery (ERAS) protocols, and ultimately improve both quality of life and long-term clinical outcomes.

MATERIALS AND METHODS

Research design

This study employed a single-center retrospective design to systematically analyze clinical data from 306 patients who underwent radical esophagectomy at our institution between January 2020 and June 2025 (Figure 1). Data were extracted from the electronic medical record system to compare the effects of conventional postoperative care (control group, n = 163) vs conventional care supplemented with "Liuzijue" Qigong training (experimental group, n = 143) on early pulmonary function recovery after surgery. The study protocol was approved by Ethics Committee of Shanghai Xuhui Central Hospital, with a waiver of informed consent.

Figure 1 This flowchart illustrates the stepwise inclusion and allocation process of 306 patients who underwent surgical treatment for esophageal cancer. DLCO: Diffusing capacity of the lung for carbon monoxide; FEV₁%: Forced expiratory volume in 1 second to forced vital capacity ratio; FVC: Forced vital capacity; MVV: Maximum voluntary ventilation; FRC: Functional residual capacity; TLC: Total lung capacity; 6MWD: 6-minute walk distance.

Study subjects

Eligible participants were adults aged 45-75 years with pathologically confirmed esophageal cancer who underwent radical esophagectomy, including transthoracic esophagectomy (TTE), Ivor Lewis procedure, or three-port minimally invasive McKeown esophagectomy, and had complete preoperative pulmonary function evaluations. Exclusion criteria included emergency or palliative surgery, severe preoperative respiratory impairment [FEV₁ < 50% predicted or diffusing capacity of the lung for carbon monoxide (DLCO) < 40% predicted], or requirement for mechanical ventilation within 24 hours postoperatively. A total of 306 patients were included, with balanced baseline characteristics (Table 1). The mean age was 58.55 ± 7.58 years; 60.5% (185/306) were male, and the average body mass index (BMI) was 24.03 ± 1.42 kg/m². There were no statistically significant differences in surgical approach distribution (P = 0.997), and preoperative pulmonary function parameters were comparable between groups (all P > 0.05).

Table 1 Baseline characteristics and postoperative pneumonia incidence in esophageal cancer patients by intervention group, n (%).

Variable	Overall (n = 306)	Control group (n = 163)	Experimental group (n = 143)	P value
Age	58.55 ± 7.58	58.43 ± 7.60	58.69 ± 7.58	0.938
Sex				0.733
Male	185	100 (61.35)	85 (59.44)
Female	121	63 (38.65)	58 (40.56)
Body mass index	24.03 ± 1.42	23.97 ± 1.41	24.11 ± 1.43	0.907
Smoking				0.649
Yes	137	71 (43.56)	66 (46.15)
No	167	92 (56.44)	77 (53.85)
Surgical technique				0.997
Transthoracic esophagectomy	250	133 (81.60)	117 (81.82)
Ivor Lewis procedure	39	21 (12.88)	18 (12.59)
Three-port minimally invasive McKeown esophagectomy	17	9 (5.52)	8 (5.59)
Surgical duration (minute)	194.62 ± 35.91	194.06 ± 36.13	195.27 ± 35.77	0.927
Intraoperative blood loss	100.38 ± 23.02	99.40 ± 23.13	101.50 ± 22.93	0.786
Postoperative pneumonia				0.005
Yes	57	40 (24.54)	17 (11.89)
No	249	123 (75.46)	126 (88.11)

Intervention program

The control group received standard postoperative respiratory rehabilitation starting 24 hours after surgery, consisting of three daily sessions of abdominal breathing training (10 minutes each), incentive spirometry (15 breaths per session, twice daily), and early ambulation (≥ 30 minutes/day beginning on postoperative day 2). The experimental group received identical standard care plus twice-daily "Liuzijue" Qigong training. The Qigong intervention began 24 hours post-surgery and continued through postoperative day 14, with two 30-minute sessions daily (at 08:00 and 16:00). Each session involved sequential vocalization of the six sounds – "Xu, He, Hu, Si, Chui, Xi" – synchronized with a controlled breathing rhythm (4-second inhalation, 6-second exhalation) and coordinated guiding movements. To ensure fidelity, certified Qigong instructors provided on-site instruction and supervision during the first three sessions. Patients also received standardized instructional videos for reinforcement during self-practice.

Observation indicators

Primary outcomes were: (1) Incidence of postoperative pneumonia, defined according to Centers for Disease Control and Prevention criteria; and (2) Changes in pulmonary function parameters – FVC, FEV₁, and MVV – from baseline (within 48 hours preoperatively) to postoperative day 14. Secondary outcomes included changes in DLCO, functional residual capacity, total lung capacity (TLC), 6-minute walk distance (6MWD), and Borg Dyspnea Scale scores. All outcomes were assessed at two time points: (1) Preoperatively (baseline); and (2) Postoperative day 14. The 14^th postoperative day was designated as the primary endpoint. A 90-day follow-up period was maintained to monitor long-term complications, including anastomotic leakage and delayed-onset pneumonia.

Statistical analysis

Statistical analyses were conducted using Statistical Package for the Social Sciences version 26.0. Continuous variables are presented as mean ± SD; for non-normally distributed data (assessed via Kolmogorov-Smirnov test, P ≤ 0.05), median (range) was used. Normality was evaluated using the Kolmogorov-Smirnov test, and homogeneity of variance was tested using Levene’s test. For normally distributed data with equal variances, independent samples t-tests were applied for intergroup comparisons. Categorical variables are expressed as frequency (percentage) and compared using the χ² test. To adjust for potential baseline imbalances, analysis of covariance was used to compare changes in pulmonary function parameters (Δvalues = postoperative value – preoperative value). All tests were two-tailed, with statistical significance set at α = 0.05.

RESULTS

Baseline characteristics and postoperative complications

A total of 306 patients who underwent radical esophagectomy for esophageal cancer were included in this study, with 163 assigned to the control group and 143 to the experimental group. As shown in Table 1, no significant differences were observed between groups in demographic characteristics (mean age: 58.55 ± 7.58 years; 60.5% male), clinical baseline data (BMI: 24.03 ± 1.42 kg/m²; smoking rate: 44.8%), surgical parameters (operation time: 194.62 ± 35.91 minutes; intraoperative blood loss: 100.38 ± 23.02 mL), or distribution of surgical approaches (TTE: 81.7%) (all P > 0.05). These results indicate good baseline comparability between the two groups. Notably, the incidence of postoperative pneumonia was significantly lower in the experimental group (11.9%, 17/143) than in the control group (24.5%, 40/163) (P = 0.005). This corresponds to an absolute risk reduction of 12.7% (95%CI: 3.7%-21.6%) and a relative risk (RR) reduction of 52% (RR = 0.48, 95%CI: 0.29%-0.83), indicating a clinically meaningful benefit of the "Liuzijue" Qigong intervention.

Preoperative pulmonary function baseline characteristics

As presented in Table 2, preoperative pulmonary function and exercise capacity were comparable between the two groups (all P > 0.05). Key parameters – including FVC (3515.4 ± 840.6 mL vs 3491.9 ± 845.2 mL), FEV₁ (2767.8 ± 740.8 mL vs 2705.2 ± 717.4 mL), and DLCO (19.9 ± 5.8 mL/minute/mmHg vs 19.8 ± 5.3 mL/minute/mmHg) – showed no significant differences. MVV (121.2 ± 39.3 L/minute vs 113.6 ± 37.4 L/minute, P = 0.084) did not differ significantly but remained within a clinically acceptable range (difference < 6.5%). Exercise tolerance, assessed by 6MWD (448.4 ± 7.9 m vs 449.7 ± 7.4 m) and Borg fatigue score [1 (0-2) vs 1 (0-3)], was also similar across groups. These findings support that subsequent between-group differences in pulmonary function changes (Δvalues) reflect the effect of the intervention rather than baseline imbalances.

Table 2 Baseline pulmonary function and exercise capacity characteristics in preoperative patients with esophageal cancer across study groups, mean ± SD.

Variable	Overall (n = 306)	Control group (n = 163)	Experimental group (n = 143)	P value
Forced vital capacity	3502.9 ± 841.8	3491.9 ± 845.2	3515.4 ± 840.6	0.808
FEV1	2734.4 ± 727.9	2705.2 ± 717.4	2767.8 ± 740.8	0.454
FEV1 to forced vital capacity ratio	90.0 ± 17.6	90.4 ± 17.8	89.5 ± 17.5	0.675
Diffusing capacity of the lung for carbon monoxide	19.8 ± 5.6	19.8 ± 5.3	19.9 ± 5.8	0.860
Maximum voluntary ventilation	117.2 ± 38.4	113.6 ± 37.4	121.2 ± 39.3	0.084
Total lung capacity	5964.4 ± 1146.7	5928.8 ± 1108.0	6005.1 ± 1192.0	0.562
Functional residual capacity	2236.8 ± 428.0	2230.9 ± 427.3	2243.4 ± 430.3	0.799
6-minute walk distance	449.1 ± 7.6	449.7 ± 7.4	448.4 ± 7.9	0.143
Modified Borg scale	1 (0-3)	1 (0-3)	1 (0-2)	0.821

FEV₁: Forced expiratory volume in 1 second.

Comparison of pulmonary function and functional indicators at 14 days post-surgery

At the 14-day postoperative assessment (Table 3), the experimental group demonstrated significantly higher FEV₁ values (2270.8 ± 797.2 mL) compared to the control group (2066.1 ± 740.5 mL) (P = 0.021), representing a 9.9% improvement. The median Borg dyspnea/fatigue score was lower in the experimental group [2 (0-4) vs 2 (1-3), P = 0.045], indicating better subjective respiratory recovery. However, no significant differences were observed in FVC (3265.4 ± 861.3 mL vs 3013.3 ± 813.6 mL, P = 0.115) or DLCO (17.1 ± 5.9 mL/minute/mmHg vs 17.0 ± 5.9 mL/minute/mmHg, P = 0.880), which may be attributable to the relatively short postoperative recovery period.

Table 3 Comparative analysis of postoperative pulmonary function and exercise capacity assessments across study groups of esophageal cancer patients, mean ± SD.

Variable	Overall (n = 306)	Control group (n = 163)	Experimental group (n = 143)	P value
Forced vital capacity	3094.4 ± 841.4	3265.4 ± 861.3	3013.3 ± 813.6	0.115
FEV1	2734.4 ± 727.9	2270.8 ± 797.2	2066.1 ± 740.5	0.021
FEV1 to forced vital capacity ratio	85.6 ± 10.1	85.1 ± 10.7	86.0 ± 9.3	0.418
Diffusing capacity of the lung for carbon monoxide	17.1 ± 5.9	17.1 ± 5.9	17.0 ± 5.9	0.880
Maximum voluntary ventilation	100.4 ± 35.6	99.1 ± 35.5	101.9 ± 35.7	0.507
Total lung capacity	5624.4 ± 1106.5	5622.3 ± 1110.3	5626.8 ± 1106.1	0.972
Functional residual capacity	2976.4 ± 592.8	2990.1 ± 606.8	2960.7 ± 578.2	0.664
6-minute walk distance	404.2 ± 14.6	404.9 ± 14.2	403.4 ± 15.0	0.379
Modified Borg scale	2 (0-4)	2 (1-3)	2 (0-4)	0.045

FEV₁: Forced expiratory volume in 1 second.

Core findings of perioperative pulmonary function changes

The experimental group showed significantly greater improvements in key pulmonary function parameters than the control group (Table 4). Accelerated lung volume recovery: ΔFVC was significantly greater in the experimental group (+502.1 ± 35.0 mL) than in the control group (+326.5 ± 26.7 mL) (P < 0.001), representing a 53.8% increase, suggesting enhanced lung expansion capacity following Qigong training. Enhanced expiratory function: ΔFEV₁ improvement was significantly higher in the experimental group (+701.7 ± 47.1 mL) than in the control group (+434.4 ± 90.3 mL) (P < 0.001), with a 61.5% increase, indicating reduced airway resistance and improved sputum clearance. Improved respiratory muscle endurance: ΔMVV increased more in the experimental group (+19.4 ± 11.7 L/minute) than in the control group (+14.4 ± 10.1 L/minute) (P < 0.001), a 34.7% improvement, suggesting enhanced diaphragmatic endurance. Secondary outcomes, including Δ6MWD and ΔTLC, did not differ significantly between groups (P > 0.05), potentially due to early postoperative activity limitations or insufficient sensitivity of the measurement tools.

Table 4 Comparison of changes in pulmonary function and functional indicators in esophageal cancer patients during the perioperative period between groups, mean ± SD.

Variable	Overall (n = 306)	Control group (n = 163)	Experimental group (n = 143)	P value
∆Forced vital capacity	408.5 ± 93.0	326.5 ± 26.7	502.1 ± 35.0	< 0.001
∆FEV1	559.3 ± 152.5	434.4 ± 90.8	701.7 ± 47.1	< 0.001
∆FEV1 to forced vital capacity ratio	4.4 ± 19.9	5.3 ± 20.4	3.5 ± 19.3	0.435
∆Diffusing capacity of the lung for carbon monoxide	2.7 ± 1.8	2.6 ± 1.8	2.8 ± 1.8	0.305
∆Maximum voluntary ventilation	16.8 ± 11.1	14.4 ± 10.1	19.4 ± 11.7	< 0.001
∆Total lung capacity	340.0 ± 699.8	306.4 ± 675.8	378.2 ± 726.7	0.371
∆Functional residual capacity	-739.6 ± 733.4	-759.2 ± 736.4	-717.3 ± 731.9	0.619
∆6-minute walk distance	45.0 ± 12.6	44.9 ± 12.7	45.0 ± 12.5	0.896
∆Modified Borg scale	-1.0 (-2 to 1)	-1.0 (-2 to 1)	-1.0 (-2 to 1)	0.815

Δ denotes the preoperative to postoperative change in measured values. FEV₁: Forced expiratory volume in 1 second.

DISCUSSION

This study is the first to demonstrate a reduction in the incidence of postoperative pulmonary complications (PPCs) associated with the "Liuzijue" Qigong training intervention. Previous evidence indicates that preoperative IMT can enhance diaphragmatic excursion (DE); however, this improvement has not consistently translated into significant gains in lung function or sustained reductions in PPCs[6,11]. Importantly, research on integrated interventions for gastrointestinal cancers suggests that the clinical efficacy of single-component approaches – such as IMT – may be limited. "Liuzijue" Qigong training, by emphasizing expiratory-phase actions such as the vocalization of "Si" and "Hu", may address a key limitation of conventional breathing exercises: Insufficient activation of expiratory muscles[12]. Potential mechanisms include: (1) Enhanced airway clearance through targeted engagement of abdominal muscles, which may improve sputum clearance efficiency[6]; and (2) Its low-intensity nature, which allows better adaptation to the postoperative physiological state. In contrast to IMT – which requires maintaining 50% of maximal inspiratory pressure – the equipment-free design of "Liuzijue" Qigong makes it more suitable for patients recovering from esophagectomy, a period during which DE typically decreases by 30%-50%[6,11].

Although preoperative IMT has been shown to improve DE, with effects lasting up to three months postoperatively, it has not significantly improved core pulmonary function parameters such as FEV₁ and FVC[6,13-15]. For example, in patients undergoing cardiac surgery, IMT enhances diaphragmatic function without producing statistically significant changes in FEV₁ or FVC[4]. The coordinated inhalation-exhalation rhythm in "Liuzijue" Qigong training may compensate for the limitations of IMT by promoting more balanced ventilation distribution. Moreover, the weak association between respiratory training and improvements in diaphragmatic endurance – such as changes in MVV – suggests that surgical trauma, including diaphragmatic nerve inhibition or pleural adhesions, may attenuate the benefits of preoperative interventions[16,17].

The control group followed the standard ERAS protocol, which includes abdominal breathing and incentive spirometry and has demonstrated efficacy in improving pulmonary function. However, the experimental group, which incorporated "Liuzijue" Qigong into the regimen, exhibited more pronounced improvements in lung function recovery. This difference may be attributed to the low-intensity, equipment-free nature of the intervention – consisting of two 30-minute sessions daily – featuring gentle movements suitable for postoperative patients and avoiding the high respiratory load associated with incentive spirometry[18,19]. At 14 days post-surgery, the experimental group showed a 9.9% higher FEV₁ than the control group, confirming its short-term clinical benefit. In patients after lung cancer surgery, respiratory training – including Qigong-based interventions – has been shown to significantly reduce pneumonia incidence and improve FEV₁[20]. A recent study on post-coronavirus disease 2019 rehabilitation highlighted the feasibility of home-based pulmonary rehabilitation using portable lung function monitoring devices, suggesting that "Liuzijue" Qigong, due to its minimal technical requirements, may be particularly well-suited for such settings[21].

The findings of this study demonstrate that "Liuzijue" Qigong training significantly reduces postoperative pneumonia incidence and improves key pulmonary function parameters, including ΔFEV₁, ΔFVC, and ΔMVV. Notably, the ΔFEV₁ improvement of 267.3 mL exceeds the minimal clinically important difference for COPD (100-140 mL) and falls within the critical range (200-400 mL) associated with reduced respiratory mortality in surgical populations, further supported by its association with a 52% reduction in pneumonia risk[20]. However, no significant differences were observed in secondary outcomes such as ΔDLCO, Δ6MWD, or ΔTLC. This is consistent with existing literature indicating that pulmonary function recovery remains incomplete at three months post-surgery[6,22]. At 14 days postoperatively, physical limitations – including incision pain and indwelling drainage tubes – likely hindered improvements in 6MWD, a finding aligned with results from previous IMT studies[11,23]. Although the Borg dyspnea/fatigue score showed a statistically significant improvement (P = 0.045), the lower scores in the experimental group are consistent with reports of improved respiratory-related fatigue following structured rehabilitation interventions[24].

The "Qi-regulating" mechanism of "Liuzijue" Qigong training in traditional Chinese medicine (TCM), which involves modulating the flow of Qi through specific vocalizations, demonstrates a plausible correspondence with modern physiological effects. This mechanism comprises three key components: (1) Prolonged exhalation and shortened inhalation (6-second exhalation/4-second inhalation), which activates the parasympathetic nervous system and reduces respiratory rate[8]; (2) The vibratory effects of consonant sounds such as "Xu" (Hsu) and "Hu" on the airways, enhancing mucociliary clearance – a mechanism analogous to the "active cycle of breathing technique" in Western respiratory therapy[9]; and (3) Diaphragm-engaged abdominal breathing, which improves oxygenation efficiency and aligns with the TCM concept of "replenishing lung Qi" through the principle of "Qi sinking to the dantian" and "earth nurturing metal". Consequently, the observed reduction in pneumonia risk and improvement in pulmonary function represent a clinical translation of traditional Qi regulation into contemporary neuro-respiratory physiological pathways.

This study employed a single-center retrospective design, which may introduce selection bias due to institution-specific clinical practices. Future multi-center RCTs are needed to confirm the generalizability of these findings. Additionally, limiting follow-up to 14 days post-surgery restricts the ability to assess long-term recovery trajectories of key pulmonary parameters such as DLCO and exercise tolerance. Mechanistic insights are further limited by the absence of direct measurements of diaphragmatic motion and sputum clearance. Future studies should incorporate advanced techniques – such as ultrasound imaging and respiratory biomechanics analysis – to better elucidate the physiological pathways underlying the effects of the "Six-Character Formula".

CONCLUSION

"Liuzijue" Qigong training significantly reduces the incidence of postoperative pneumonia and accelerates recovery of core pulmonary function parameters in patients undergoing esophagectomy, with a favorable safety profile. These findings suggest that traditional Qigong may serve as a valuable adjunct to postoperative respiratory rehabilitation in the context of esophageal cancer surgery.

ACKNOWLEDGEMENTS

We gratefully acknowledge the invaluable contributions of all colleagues in the Department of Thoracic Surgery at Shanghai Xuhui Central Hospital. Their dedicated efforts in clinical data collection and patient management were instrumental in the successful execution of this study.