Retrospective study on the effects of different acupuncture protocols on gastrointestinal function recovery after general anesthesia gastrointestinal endoscopy

Abstract

BACKGROUND

Gastrointestinal dysfunction frequently occurs following painless gastroscopic general anesthesia, and the efficacy of conventional acupuncture and moxibustion is limited. Therefore, there is an urgent need to optimize the recovery protocol.

AIM

To investigate and analyze the effects of two distinct acupuncture protocols on the recovery of gastrointestinal function following general anesthesia during gastrointestinal endoscopy.

METHODS

A retrospective review was conducted on medical records of 80 patients who underwent elective gastrointestinal endoscopy under general anesthesia at our hospital's endoscopy center from October 2024 to October 2025. Patients were categorized based on the postoperative acupuncture protocol received: A conventional group receiving acupuncture at Zusanli (ST36) and Neiguan (PC6) and an optimized group receiving acupuncture at Zusanli (ST36), Neiguan (PC6), Shangjuxu (ST37), and Zhongwan (CV12), combined with electroacupuncture stimulation, with 40 patients in each group. Comparison between the two groups was performed based on indicators such as postoperative gastrointestinal function recovery time (including time to first flatus, first defecation, and bowel sound recovery), abdominal distension and pain visual analog scale scores, incidence of complications, and patient satisfaction levels.

RESULTS

Patients in the optimized group exhibited significantly shorter times to first flatus, first defecation, and bowel sound recovery compared to the conventional group (P < 0.05). At 6 hours and 12 hours postoperatively, visual analog scale scores for abdominal distension and pain were significantly lower in the optimized group (P < 0.05), and the overall patient satisfaction rate was higher (P < 0.01). Forest plots indicated that the optimized group experienced an average reduction in time to first flatus of 3.29 hours [95% confidence interval (CI): -4.28 to -2.30], an average reduction in time to first defecation of 6.87 hours (95%CI: -10.07 to -3.67), and an average reduction in time to bowel sound recovery of 2.00 hours (95%CI: -2.69 to -1.31) compared to the conventional group, with statistically significant differences (P < 0.05). The Kaplan-Meier curve revealed that the cumulative probability of first flatus was consistently higher in the optimized group (Log-rank test, χ² = 15.32, P < 0.05). No statistically significant differences were observed between the two groups concerning anesthetic dosage, procedure duration, or total incidence of complications (P > 0.05).

CONCLUSION

The optimized integrated acupuncture protocol, which includes additional gastrointestinal meridian points and electroacupuncture stimulation, significantly enhances the early recovery of gastrointestinal function following general anesthesia during gastrointestinal endoscopy, alleviates postoperative abdominal distension and pain, improves patient comfort and satisfaction, and demonstrates favorable safety profiles, thereby warranting clinical promotion.

Key Words: Acupuncture; General anesthesia; Gastrointestinal endoscopy; Gastrointestinal function recovery; Retrospective study; Electroacupuncture

Core Tip: This study examines the impact of an optimized acupuncture protocol on the recovery of gastrointestinal function following general anesthesia for gastrointestinal endoscopy. The optimized protocol incorporates Shangjuxu (ST37), Zhongwan (CV12), and electroacupuncture in addition to conventional acupuncture points. It significantly shortens recovery time, alleviates abdominal discomfort, and enhances patient satisfaction while maintaining a high level of safety, thus offering a better clinical option.

INTRODUCTION

Painless gastrointestinal endoscopy has emerged as an essential diagnostic and therapeutic modality within the field of clinical gastroenterology. The administration of intravenous anesthesia facilitates the procedure while ensuring that the patient remains unconscious and free from pain, thereby significantly enhancing patient tolerance and compliance with the examination[1,2]. However, the utilization of general anesthetic agents such as propofol and remifentanil, in conjunction with the mechanical stimulation of the gastrointestinal mucosa during the endoscopic procedure, frequently results in postoperative gastrointestinal dysfunction. This dysfunction may present as diminished or absent bowel sounds, delayed passage of flatus and stool, abdominal distension, pain, nausea, and vomiting, which not only exacerbate patient discomfort but also impede subsequent oral intake and recovery, potentially increasing the risk of postoperative complications[3,4].

From the perspective of traditional Chinese medicine, postoperative gastrointestinal dysfunction is classified under “abdominal distension” and “intestinal obstruction”. This condition is primarily attributed to disturbances in qi movement, disharmony between the spleen and stomach, and obstruction of the meridians. Acupuncture has the potential to regulate the flow of qi and blood, harmonize the functions of the zang-fu organs, and restore gastrointestinal motility. However, the optimal combination of acupoints and stimulation modalities remains undefined, and conventional protocols may not fully achieve the desired therapeutic outcomes. Consequently, exploring optimized acupuncture strategies is of significant clinical importance.

Recent research has shown that acupuncture can modulate the autonomic nervous system, increase vagal activity, regulate the secretion of gastrointestinal hormones like motilin and gastrin, and enhance intestinal microcirculation. These effects collectively contribute to improved gastrointestinal peristalsis and functional recovery.

Acupuncture, a fundamental practice within traditional Chinese medicine, possesses a rich historical background and considerable empirical support for its efficacy in regulating gastrointestinal function. It facilitates the restoration of gastrointestinal motility through various mechanisms, including the modulation of autonomic nervous system balance, stimulation of gastrointestinal hormone secretion, enhancement of gastrointestinal blood flow, and attenuation of inflammatory responses[5,6]. Presently, the combination of Zusanli (ST36) and Neiguan (PC6) is frequently employed in clinical acupuncture interventions targeting gastrointestinal function, demonstrating a degree of therapeutic benefit. Nevertheless, some patients continue to encounter suboptimal recovery outcomes, including prolonged abdominal distension and delayed initiation of bowel movements[7,8]. Consequently, investigating optimized acupuncture protocols aimed at further enhancing the recovery of gastrointestinal function following general anesthesia in gastrointestinal endoscopy is of considerable clinical significance. This study conducts a retrospective analysis of the effects of various acupuncture protocols on patients undergoing painless gastrointestinal endoscopy, with the objective of providing robust evidence-based support for clinical practice.

MATERIALS AND METHODS

Study subjects

Approved by the hospital’s medical ethics committee, a retrospective collection of medical records was conducted for 80 patients who underwent elective painless gastrointestinal endoscopy at the hospital’s endoscopy center between October 2024 and October 2025.

Inclusion criteria: (1) Age 18-75 years; (2) American Society of Anesthesiologists physical status I-II; (3) Successful completion of gastrointestinal endoscopy under general anesthesia without endoscopic treatments such as polypectomy or hemostasis; (4) Receipt of acupuncture intervention within 6 hours postoperatively; (5) Complete clinical data; and (6) Informed consent from patients and their families.

Exclusion criteria: (1) History of abdominal surgery; (2) Severe cardiac, pulmonary, hepatic, or renal insufficiency; (3) Gastrointestinal motility disorders, such as irritable bowel syndrome and paralytic ileus, have been diagnosed; (4) Coagulation dysfunction or skin infection at acupuncture sites; (5) Pregnancy or lactation; and (6) Extreme fear or refusal of acupuncture.

Based on the postoperative acupuncture protocol, patients were categorized into a conventional group and an optimized group, comprising 40 patients each. No statistically significant differences were observed between the two groups regarding baseline characteristics, such as gender, age, body mass index, American Society of Anesthesiologists classification, type of procedure, anesthetic dosages (propofol and remifentanil), and duration of the procedure (all P > 0.05), as illustrated in Table 1.

Table 1 Comparison of baseline data between the two groups, n (%)/mean ± SD.

Item	Conventional group (n = 40)	Optimized group (n = 40)	t/χ2 value	P value
Gender			χ2 = 0.210	0.651
Male	22 (55.00)	24 (60.00)
Female	18 (45.00)	16 (40.00)
Age (years)	52.32 ± 9.75	50.84 ± 9.45	t = 0.708	0.481
BMI (kg/m2)	22.54 ± 2.86	23.18 ± 3.07	t = -0.985	0.327
ASA classification			χ2 = 0.521	0.472
Class I	28 (70.00)	25 (62.50)
Class II	12 (30.00)	15 (37.50)
Procedure type			χ2 = 0.681	0.712
Gastroscopy	12 (30.00)	10 (25.00)
Colonoscopy	10 (25.00)	13 (32.50)
Combined endoscopy	18 (45.00)	17 (42.50)
Propofol dosage (mg)	180.55 ± 45.34	175.89 ± 48.65	t = 0.456	0.649
Remifentanil dosage (μg)	105.24 ± 25.76	101.86 ± 28.43	t = 0.568	0.571
Procedure duration (minute)	25.82 ± 8.25	24.37 ± 7.94	t = 0.812	0.419

BMI: Body mass index; ASA: American Society of Anesthesiologists Physical Status Classification.

Study methods

All patients underwent acupuncture in the post-anesthesia care unit following the regaining of consciousness and stabilization of vital signs. The procedures were performed by a consistent team of licensed acupuncturists.

Conventional group: (1) Patients were positioned in a supine orientation. Bilateral Zusanli (ST36) and Neiguan (PC6) acupoints were selected and routinely disinfected prior to intervention; (2) Disposable sterile acupuncture needles (0.25 mm × 40 mm) were inserted perpendicularly; and (3) After achieving “deqi” (needle sensation), a reinforcing-reducing manipulation was subsequently applied. The needles were retained for a duration of 30 minutes, during which one additional manipulation was conducted.

Optimized group: (1) Patients were positioned in a supine position. In addition to the acupoints utilized in the conventional group, bilateral Shangjuxu (ST37) and Zhongwan (CV12) were selected; (2) After needle insertion and achieving “deqi”, the needles were connected to a Huatuo SDZ-V electronic acupuncture stimulator; (3) One pair of electrodes was connected to bilateral Zusanli (ST36), and another pair was connected to unilateral Shangjuxu (ST37) and Zhongwan (CV12), alternating between left and right sides; and (4) Parameters were configured for continuous wave stimulation, utilizing alternating frequencies of 2 Hz and 100 Hz to create a dense-disperse wave pattern. Intensity was adjusted to a level deemed tolerable by the patient, typically ranging from 1 mA to 3 mA, which induced mild local muscle twitching. The duration of stimulation was set for 30 minutes.

Observation indicators

The primary outcomes included gastrointestinal function recovery indicators: (1) Time to first flatus: Defined as the time from the end of the procedure to the first passage of gas per rectum; (2) Time to first defecation: Defined as the time from the end of the procedure to the first bowel movement; and (3) Time to bowel sound recovery: Assessed through auscultation, is defined as the duration until regular bowel sounds (≥ 3 times/minute) are detected.

Secondary outcomes included

Secondary outcomes included: (1) Abdominal distension and pain scores, assessed using the visual analog scale (VAS, 0-10), recorded at 2 hours, 6 hours, 12 hours, and 24 hours postoperatively; (2) Incidence of postoperative complications, including nausea, vomiting, dizziness, and others; and (3) Patient satisfaction, evaluated using a three-level scale (very satisfied, satisfied, dissatisfied).

Statistical analysis

Statistical analysis was performed using SPSS 26.0 software. Continuous data were tested for normal distribution and are presented as mean ± SD. Between-group comparisons for continuous data were performed using the t-test. Categorical data are expressed as n (%), with comparisons between groups conducted using the χ² test. To evaluate the main effects of “time” (2 hours, 6 hours, 12 hours, and 24 hours postoperatively) and “group” (conventional, optimized), as well as their interaction, repeated-measures analysis of variance was employed. Forest plots were generated using RevMan 5.4 software to illustrate the differences in effect between the two acupuncture protocols, with time to first flatus as the effect measure. Additionally, Kaplan-Meier survival curves were plotted for time to first flatus in both groups, and the Log-rank test was used for comparison. A P value of < 0.05 was deemed statistically significant.

RESULTS

Comparison of gastrointestinal function recovery time between the two groups

The optimized group demonstrated significantly shorter durations until the occurrence of first flatus, first defecation, and recovery of bowel sounds when compared to the conventional group, with statistically significant differences observed (P < 0.05). The forest plot indicated that the optimized group experienced an average reduction in time to first flatus of 3.29 hours [95% confidence interval (CI): -4.28 to -2.30], an average reduction in time to first defecation of 6.87 hours (95%CI: -10.07 to -3.67), and an average reduction in time to bowel sound recovery of 2.00 hours (95%CI: -2.69 to -1.31) relative to the conventional group, all with statistically significant differences (P < 0.05). The Kaplan-Meier curve demonstrated that the cumulative probability of the first occurrence of flatus was consistently greater in the optimized group (Log-rank test, χ² = 15.32, P < 0.05) (Table 2). As illustrated in Figure 1, the forest plot demonstrates that the optimized group showed a consistent reduction in all indicators of gastrointestinal recovery time, with confidence intervals not crossing zero, indicating statistically significant differences. Figure 2 presents the Kaplan-Meier curve for the time to first flatus, showing that the cumulative probability of flatus occurrence was significantly higher in the optimized group throughout the observation period.

Figure 1 Forest plot of the impact of different acupuncture protocols on recovery time in two groups. CI: Confidence interval.

Figure 2 Kaplan-Meier curve of first flatus time in two groups of patients.

Table 2 Comparison of gastrointestinal function recovery time between two groups (hour), mean ± SD.

Group	n	Time to first flatus (hour)	Time to first defecation (hour)	Time to bowel sound recovery (hour)
Conventional group	40	8.54 ± 2.63	28.36 ± 7.97	5.78 ± 1.69
Optimized group	40	5.25 ± 1.82	21.49 ± 6.55	3.78 ± 1.44
t value	-	6.703	4.342	5.832
P value	-	< 0.001	< 0.001	< 0.001

Comparison of postoperative abdominal distension and pain VAS scores between the two groups

At 2 hours postoperatively, no significant differences were observed in VAS scores for abdominal distension and pain between the two groups (P > 0.05). However, at 6 and 12 hours postoperatively, the optimized group exhibited significantly lower VAS scores for both abdominal distension and pain compared to the conventional group (P < 0.05). By 24 hours postoperatively, scores in both groups decreased to low levels, resulting in no statistically significant differences (P > 0.05). A repeated-measures analysis of variance indicated that the main effects of “time” and “group”, as well as the interaction between “time” and “group”, were statistically significant (P < 0.05). Refer to Tables 3 and 4 for detailed results.

Table 3 Comparison of postoperative abdominal distension scores between two groups, mean ± SD.

Group	n	2 hours postop	6 hours postop	12 hours postop	24 hours postop
Conventional group	40	3.11 ± 1.22	4.54 ± 1.46	3.84 ± 1.32	1.57 ± 0.86
Optimized group	40	2.93 ± 1.15	3.37 ± 1.12	2.65 ± 1.08	1.35 ± 0.79
t value	-	0.694	4.080	4.494	1.207
P value	-	0.490	< 0.001	< 0.001	0.231
Main effect of “time”	F = 85.632, P < 0.001	-	-	-	-
Main effect of “group”	F = 18.945, P < 0.001	-	-	-	-
“Time × group” interaction	F = 9.287, P < 0.001	-	-	-	-

Table 4 Comparison of postoperative abdominal pain visual analog scale scores between two groups, mean ± SD.

Group	n	2 hours postop	6 hours postop	12 hours postop	24 hours postop
Conventional group	40	2.02 ± 0.93	2.85 ± 1.23	2.22 ± 1.06	0.89 ± 0.50
Optimized group	40	1.86 ± 0.82	1.94 ± 0.81	1.43 ± 0.75	0.71 ± 0.42
t value	-	0.824	4.074	3.872	1.788
P value	-	0.412	< 0.001	< 0.001	0.077
Main effect of “time”	F = 64.118, P < 0.001	-	-	-	-
Main effect of “group”	F = 14.326, P < 0.001	-	-	-	-
“Time × group” interaction	F = 5.046, P = 0.002	-	-	-	-

Comparison of complication incidence between the two groups

Postoperative complications occurred in 27.50% (11/40) of the conventional group and 17.50% (7/40) of the optimized group. Although the incidence appeared lower in the optimized group, the difference was not statistically significant (χ² = 1.195, P = 0.274), as shown in Table 5.

Table 5 Comparison of complication incidence rates between two groups, n (%).

Group	n	Nausea	Vomiting	Dizziness	Other	Total incidence
Conventional group	40	5 (12.50)	2 (5.00)	3 (7.50)	1 (2.50)	11 (27.50)
Optimized group	40	4 (10.00)	1 (2.50)	2 (5.00)	0 (0.00)	7 (17.50)
χ2 value	-	-	-	-	-	1.195
P value	-	-	-	-	-	0.274

Comparison of satisfaction between the two groups

The total satisfaction rate was markedly higher in the optimized group (97.50%) relative to the conventional group (85.00%). The difference was statistically significant (χ² = 4.320, P = 0.038), as shown in Table 6.

Table 6 Comparison of patient satisfaction between two groups, n (%).

Group	n	Very satisfied	Satisfied	Dissatisfied	Total satisfaction rate
Conventional group	40	18 (45.00)	16 (40.00)	6 (15.00)	34 (85.00)
Optimized group	40	27 (67.50)	12 (30.00)	1 (2.50)	39 (97.50)
χ2 value	-	-	-	-	4.320
P value	-	-	-	-	0.038

DISCUSSION

In recent years, the enhanced recovery after surgery concept has gained acceptance, making the rapid recovery of organ function during the perioperative period an important measure of medical quality[9,10]. Despite advances in anesthesia techniques and perioperative management, gastrointestinal motility inhibition caused by general anesthesia and invasive procedures remains a prevalent and unresolved clinical issue[11,12]. Early recovery of gastrointestinal function is not only linked to nutritional intake and time to ambulation for patients undergoing painless gastrointestinal endoscopy but also closely tied to hospital stay length, medical costs, and overall prognosis[13,14]. Preliminary studies have shown that acupuncture can gently promote gastrointestinal motility through various regulatory pathways involving the nervous, endocrine, and immune systems. This approach results in few adverse effects and high patient acceptance[15,16]. This study retrospectively analyzed the effects of different acupoint combinations and stimulation methods, aiming to contribute to an integrative approach that combines traditional Chinese and Western medicine to improve patient experience and enhance recovery efficiency.

The results indicated that the optimized group experienced significantly shorter times to first flatus, first defecation, and bowel sound recovery compared to the conventional group (P < 0.05). The optimized acupuncture protocol combined the acupoints Zusanli (ST36), Neiguan (PC6), Shangjuxu (ST37), and Zhongwan (CV12) with electroacupuncture stimulation, effectively integrating traditional meridian theory with modern medical understanding to create a more systematic acupoint combination. Zusanli, the He-sea point of the Stomach Meridian, is essential for regulating gastrointestinal function[17,18]. Neiguan effectively calms the mind and alleviates nausea, which is common postoperative nausea[19]. The addition of Shangjuxu, the Lower He-sea point of the Large Intestine Meridian, specifically aids in the descending and clearing functions of the large intestine. Zhongwan, as the Front-Mu point of the Stomach and the Influential point of the Fu organs, excels in harmonizing the middle energizer, relieving distension, and resolving fullness[20-22]. This combination of four acupoints - Zusanli, Neiguan, Shangjuxu, and Zhongwan - addresses the stomach, intestines, and the qi dynamics of the middle energizer, achieving synergy between “He-sea and Front-Mu point pairing” and “local-distal point pairing”. Compared to the conventional protocol that utilized only Zusanli and Neiguan, the optimized approach enhances both the breadth and depth of regulation[23,24]. Furthermore, the optimized group used electroacupuncture with an alternating dense-disperse wave mode, leveraging the advantages of varying frequencies. Low-frequency stimulation activates the endogenous opioid peptide system, providing analgesic and stress-relieving effects, while high-frequency stimulation excites motor nerves and smooth muscles, directly enhancing gastrointestinal motility[25,26]. The optimized acupuncture protocol offers continuous and stable electrophysiological signal input, minimizing variability in efficacy caused by manual needle manipulation and prolonging effective stimulation duration. This approach fully mobilizes the rhythmic contractions of gastrointestinal smooth muscle. Forest plot and Kaplan-Meier survival curve analyses revealed that the optimized group had an average reduction in time to first flatus by 3.29 hours, time to first defecation by 6.87 hours, and time to bowel sound recovery by 2.00 hours compared to the conventional group. These findings visually confirm the significant advantage of the optimized protocol in promoting early recovery of gastrointestinal function, supported by effect size and cumulative probability. These results align with those reported in the randomized controlled trial by Li et al[27].

Furthermore, the study results showed that the optimized group had lower VAS scores for abdominal distension and pain at 6 hours and 12 hours postoperatively compared to the conventional group (P < 0.05), as well as a higher overall satisfaction rate (P < 0.01). Mechanistically, electroacupuncture alleviates abdominal distension by enhancing gastrointestinal motility. The low-frequency component’s activation of the opioid peptide system contributes to both central and peripheral pain regulation, demonstrating superior analgesic effects during the postoperative pain-sensitive period (6-12 hours)[28,29]. The improvement in patient satisfaction reflects faster recovery of gastrointestinal function, symptom alleviation, and the increased comfort associated with electroacupuncture treatment, which reduces the need for frequent manual needle manipulation and offers relatively stable stimulation parameters[30]. Furthermore, the results indicated no statistically significant difference in the total incidence of postoperative complications between the two groups (P > 0.05), suggesting that, under the parameters and operational standards set for the optimized group, the addition of acupoints and electroacupuncture did not increase the risk of adverse reactions, demonstrating favorable safety.

As a retrospective study, this research has limitations, particularly since the optimized protocol incorporated both additional acupoints and electroacupuncture application as variables. Future studies should employ factorial designs to isolate the individual contributions of these factors and determine potential interactions, providing more precise guidance for optimizing clinical protocols.

CONCLUSION

In summary, the optimized integrated acupuncture protocol, which includes additional gastrointestinal meridian points and electroacupuncture stimulation, effectively promotes early recovery of gastrointestinal function following general anesthesia gastrointestinal endoscopy, alleviates postoperative abdominal distension and pain, enhances patient comfort and satisfaction, and demonstrates good safety, making it worthy of clinical promotion. However, further prospective randomized controlled studies are needed to validate the findings of this study.