Effects of comprehensive nutrition support on immune function, wound healing, hospital stay, and mental health in gastrointestinal surgery

Abstract

BACKGROUND

Postoperative patients undergoing gastrointestinal surgery often encounter challenges such as low immune function, delayed wound healing owing to surgical trauma, and increased nutritional demands during recovery.

AIM

To assess the effect of comprehensive nutritional support program on immune function and wound healing in patients undergoing gastrointestinal surgery.

METHODS

This retrospective comparative study included 60 patients who underwent gastrointestinal surgery, randomly assigned to either the experimental group (n = 30) or the control group (n = 30). The experimental group received comprehensive nutritional support, including a combination of enteral and parenteral nutrition, whereas the control group received only conventional comprehensive nutritional support. Evaluation indicators included immune function markers (e.g., white blood cell count, lymphocyte subsets), wound healing (wound infection rate, healing time), pain score [visual analog scale (VAS) score], and psychological status (anxiety score, depression score) 7 days post-surgery) and duration of stay.

RESULTS

The immune function of patients in the experimental group was significantly better than that in the control group. The white blood cell count was 8.52 ± 1.19 × 10⁹/L in the experimental group vs 6.74 ± 1.31 × 10⁹/L (P < 0.05). The proportion of CD4+ T cells was higher in the experimental group (40.09% ± 4.91%) than that in the control group (33.01% ± 5.08%) (P < 0.05); the proportion of CD8+ T cells was lower (21.79% ± 3.38% vs 26.29% ± 3.09%; P < 0.05). The CD4+/CD8+ ratio was 1.91 ± 0.32 in the experimental group whereas 1.13 ± 0.23 in the control group (P < 0.05). The wound infection rate of the experimental group was significantly lower than that of the control group (10% vs 30%, P < 0.05), and the wound healing time was shorter (10.35 ± 2.42 days vs 14.42 ± 3.15 days, P < 0.05). The VAS score of the experimental group was 3.05 ± 1.04, and that of the control group was 5.11 ± 1.09 (P < 0.05); the anxiety score (Hamilton Anxiety Rating Scale) was 8.88 ± 1.87, and that of the control group was 12.1 ± 3.27 (P < 0.05); the depression score (Hamilton Depression Rating Scale) was 7.37 ± 1.41, and that of the control group was 11.79 ± 2.77 (P < 0.05). In addition, the hospitalization time of the experimental group was significantly shorter than that of the control group (16.16 ± 3.12 days vs 20.93 ± 4.84 days, P < 0.05).

CONCLUSION

A comprehensive nutritional support program significantly enhances immune function, promote wound healing, reduces pain, improves psychological status, and shortens hospitalization stays in patients recovering from gastrointestinal surgery.

Key Words: Comprehensive nutritional support; Gastrointestinal surgery; Immune function; Wound healing; Pain score; Psychological score; Hospital stay

Core Tip: In the rehabilitation management of patients after gastrointestinal surgery, a comprehensive nutritional support program can significantly improve immune function, promote wound healing, reduce pain and anxiety, and shorten hospitalization time. Therefore, comprehensive nutritional support should be considered an important part of the rehabilitation management of patients after gastrointestinal surgery and deserves to be widely promoted and applied in clinical practice.

INTRODUCTION

Gastrointestinal surgery is a common procedure used to treat various diseases, including stomach and colon cancer, ulcerative colitis, and Crohn’s disease[1,2]. Despite advances in surgical techniques and anesthetic management improving patient outcomes, postoperative complications such as immunocompromise, poor wound healing, pain, and psychological distress continue to be significant clinical issues[3,4]. These complications can extend hospitalization and increase medical costs, along with long-term health problems thereby affecting the quality of life[5]. The physiological stress response caused by surgical trauma and anesthesia often results in significant decline in immune function[6], increasing susceptibility to infections, particularly wound infections[7]. In addition, insufficient nutritional intake post-surgery, exacerbates immune dysfunction and impairs the wound healing process[8,9].

Comprehensive nutritional support is increasingly recognized, particularly after gastrointestinal surgery[10]. Nutritional requirements increase after surgery mainly because of the high metabolic state caused by surgical trauma, tissue repair needs, and consumption of energy and nutrients in stress responses[11,12]. Adequate nutritional support, providing essential energy, proteins, vitamins, and trace elements, is crucial for maintaining immune function and promoting wound healing[13]. This support primarily includes enteral nutrition (EN) and parenteral nutrition (PN). EN provides nutrition to the digestive tract[14,15]. This method is more consistent with physiological conditions, helps preserve the intestinal barrier function, and reduces the risk of infection[16]. PN provides nutrition through intravenous injection and is suitable for patients with impaired digestive tract function or who cannot tolerate EN[17]. In clinical practice, a comprehensive nutritional support program often combines EN and PN based on individual patient needs to ensure optimal care[18].

Postoperative nutritional status significantly impacts immune function. Malnutrition impairs immune cell production and function, thereby increasing the risk of infection. Research has demonstrated that reasonable comprehensive nutritional support can promote immune cell production and enhance the body’s ability to resist infection. In particular, proteins and specific micronutrients (such as vitamin A, vitamin C, and zinc) are essential for maintaining and enhancing immune functions[19]. Postoperative pain and psychological stress are important factors affecting patient recovery. Pain affects comfort and can also lead to psychological problems such as anxiety and depression. Adequate comprehensive nutritional support can alleviate postoperative pain and improve psychological status through various mechanisms[20]. Good nutritional status can enhance the patient’s overall health and resistance as well as reduce pain perception.

Given the importance of comprehensive nutritional support in postoperative recovery, this study aimed to explore its effects on immune function, wound healing, pain scores, psychological status, and hospital stay duration in patients following gastrointestinal surgery. By comparing patients receiving comprehensive nutritional support to those receiving conventional nutritional support, we evaluated its clinical effect and provided guidance for clinical practice. The findings offer clinicians with empirical data concerning postoperative nutritional support management, assisting in the development of scientifically informed nutritional support plans, enhancing recovery, reducing complications, shortening hospitalization stays, and improving patient quality of life. This study also lays a foundation for future research and advancements in postoperative comprehensive nutritional support.

MATERIALS AND METHODS

Patient information

This study included 60 patients who underwent gastrointestinal surgery at our hospital between January 2023 and December 2023. The patient’s age ranged from 30 to 70 years, with an average age of 50.5 years. All patients had a confirmed pathological diagnosis and underwent surgery for the first time. None had severe heart, liver, kidney, or other important organ dysfunction before surgery.

Research design

This retrospective comparative study aimed to explore the impact of a comprehensive nutritional support program on immune function, wound healing, pain scores, psychological status, and hospital stay duration in patients after gastrointestinal surgery. Sixty patients were randomly divided into experimental and control groups, with 30 patients in each (Table 1). The experimental group received comprehensive nutritional support, including a combination of EN and PN, whereas the control group received only conventional comprehensive nutritional support.

Table 1 Comparison of general data between the two groups, n (%).

Index	Experimental group (n = 30)	Control group (n = 30)	t/F	P value
Age (years)	48.38 ± 9.18	52.94 ± 9.73	-1.87	0.07
Sex (male/female)	18/12	17/13	0.26	0.80
BMI (kg/m²)	23.02 ± 2.89	23.89 ± 3.21	-1.10	0.28
Type of operation	Stomach cancer: 20; colon cancer: 10	Stomach cancer: 18; colon cancer: 12	-3.27	0.58
Underlying disease	12 (40)	14 (46.7)	2.17	0.62

BMI: Body mass index.

Inclusion and exclusion standards

The inclusion criteria were as follows: Age between 30 and 70 years; pathological diagnosis of gastrointestinal disease necessitating gastrointestinal surgery; gastrointestinal surgery for the first-time; no severe heart, liver, or kidney dysfunction before surgery. Patients provided informed consent and signed an informed consent form.

The exclusion criteria included: Age < 30 years or > 70 years; severe dysfunctions in important organs such as the heart, liver, and kidneys before surgery; severe malnutrition or obesity [body mass index (BMI) < 18.5, BMI > 30] before surgery; postoperative complications such as anastomotic leakage and severe infection requiring secondary surgery. Patients who failed to follow the study protocol or dropped-out midway through the study were also excluded.

Grouping situation

Following enrollment, the 60 patients were randomly divided into experimental and control group using a random number table method, with 30 patients in each group. This random grouping was conducted before surgery to ensure that there was no significant difference (P > 0.05) and comparability between the two groups of patients in terms of preoperative general information, including age, sex, and disease type.

Interventions

Experimental group (comprehensive nutritional support): EN: Commenced EN 24 hours post-surgery. Nutritional preparations were administered via nasogastric or gastrointestinal tubes. The total daily calorific intake was 25-30 kcal/kg and protein intake was 1.5-2.0 g/kg. The amount and concentration of the nutrient solution was gradually increased according to the patient’s tolerance until full comprehensive nutritional support was achieved.

PN: Supplemental PN was administered when EN is insufficient. Hypertonic glucose, lipid emulsions, amino acid solutions, and electrolytes were administered through a central venous catheter to ensure that the daily total caloric and nutrient intakes reached target levels.

Nutritional monitoring and adjustment: The patient’s blood sugar, electrolytes, liver and kidney function, and other indicators were monitored daily. The comprehensive nutritional support plan was adjusted based on these results to ensure the safety and effectiveness of nutritional intake.

Control group (routine comprehensive nutritional support): The patient’s oral diet was gradually resumed post-surgery, based on their eating status. Patients fasted for 24 hours post-surgery and received intravenous infusion support. After intestinal function was restored, a liquid or semi-liquid diet was gradually initiated, and finally, a normal diet was restored. The control group did not receive any additional comprehensive EN or PN nutritional support.

Observation indicators

Immune function indicators: White blood cell (WBC) counts: 7 days post-surgery, venous blood was drawn to determine WBC counts.

CD4+ T cell proportion: The proportion of CD4+ T cells in peripheral blood was measured by flow cytometry 7 days post-surgery.

Proportion of CD8+ T cells: The proportion of CD8+ T cells in peripheral blood was measured by flow cytometry 7 days post-surgery.

CD4+/CD8+ ratio: Calculated based on the ratio of CD4+ T cells and CD8+ T cells.

Wound healing status: Wound infection rate: Wound infections were recorded within 7 days post-surgery.

Wound healing time: The time (in days) from the end of surgery to complete wound healing was recorded.

Pain score [visual analog scale (VAS) score]: A VAS was used to evaluate patient pain levels 3 and 7 days post-surgery. The score range was 0-10, with 0 indicating no pain and 10 indicating severe pain.

Mental condition: Anxiety Rating Scale [Hamilton Anxiety Rating Scale (HAMA)]: The HAMA was used to assess the patient’s anxiety levels 7 days post-surgery.

Depression score [Hamilton Depression Rating Scale (HAMD)]: The HAMD was used to evaluate patient depression levels 7 days post-surgery.

Duration of stay: The total duration of stay (in days) from the end of surgery till discharge.

Statistical analysis

All data were analyzed using SPSS v.26.0 statistical software. Measurement data are expressed as means ± SD, and comparison between groups were performed using independent sample Student’s t-test. Enumeration data were expressed as number of cases and percentages, and the χ² test was used for comparison between groups. Statistical significance was set at P < 0.05.

RESULTS

Immune function indicators

Immune function indicators of patients in the experimental group 7 days post-surgery were significantly better than those in the control group. WBC count in the experimental group was 8.52 ± 1.19 × 10⁹/L, compared to 6.74 ± 1.31 × 10⁹/L in the control group (P < 0.05); the proportion of CD4+ T cells in the experimental group was 40.09% ± 4.91% whereas 33.01% ± 5.08% in the control group (P < 0.05); the proportion of CD8+ T cells in the experimental group was 21.79% ± 3.38%, and that in the control group was 26.29% ± 3.09% (P < 0.05); and the CD4+/CD8+ ratio in the experimental group was 1.91 ± 0.32, compared to 1.13 ± 0.23 in the control group (P < 0.05; Table 2).

Table 2 Comparison of immune function indexes on the seventh day after surgery between the two groups.

Index	Experimental group (n = 30)	Control group (n = 30)	t	P value
White blood cell count (× 109/L)	8.52 ± 1.19	6.74 ± 1.31	5.51	< 0.05
CD4+ T cell ratio (%)	40.09 ± 4.91	33.01 ± 5.08	5.49	< 0.05
CD8+ T cell ratio (%)	21.79 ± 3.38	26.29 ± 3.09	-5.38	< 0.05
CD4+/CD8+ ratio	1.91 ± 0.32	1.13 ± 0.23	11.00	< 0.05

Wound healing status

Wound healing was significantly better in the experimental group than in the control cohort. The wound infection rate in the experimental group was 10% and that in the control group was 30% (P < 0.05); the wound healing time in the experimental group was 10.35 ± 2.42 days, compared to 14.42 ± 3.15 days in the control group (P < 0.05). VAS scores of patients in the experimental group were significantly lower than those in the control group (Table 3).

Table 3 Comparison of wound healing between the two groups, n (%).

Index	Experimental group (n = 30)	Control group (n = 30)	t	P value
Wound infection rate	3 (10)	9 (30)	-3.62	< 0.05
Wound healing time (days)	10.35 ± 2.42	14.42 ± 3.15	-5.62	< 0.05

Comparison of pain scores and hospital stay

Three days post-surgery, the VAS score of the experimental group was 3.1 ± 1.0, and that of the control group was 5.0 ± 1.2 (P < 0.05). Seven days post-surgery, the VAS score of the experimental group was 3.05 ± 1.04, compared to 5.0 ± 1.2 in the control group (P < 0.05). It is 5.11 ± 1.09 (P < 0.05). The length of hospital stay was significantly shorter in the experimental group than in the control group. The average hospitalization time of the experimental group was 16.16 ± 3.12 days and that of the control group was 20.93 ± 4.84 days (P < 0.05; Table 4).

Table 4 Comparison of pain score (visual analog scale) and length of stay between the two groups.

Index	Experimental group (n = 30)	Control group (n = 30)	t	P value
VAS score on day 3 after surgery	3.05 ± 1.04	5.11 ± 1.09	-7.12	< 0.05
VAS score on the 7th day after surgery	2.19 ± 0.93	4.43 ± 1.05	-8.80	< 0.05
Length of stay (days)	16.16 ± 3.12	20.93 ± 4.84	-4.53	< 0.05

Vas: Visual analog scale.

Psychological condition

Anxiety and depression scores of patients in the experimental group were significantly lower than those in the control group. Seven days post-surgery, the HAMA score of the experimental group was 8.88 ± 1.87 and that of the control group was 12.1 ± 3.27 (P < 0.05); the HAMD score of the experimental group was 7.37 ± 1.41, compared to 11.79 ± 2.77 in the control group (P < 0.05; Table 5).

Table 5 Comparison of psychological status scores between the two groups.

Index	Experimental group (n = 30)	Control group (n = 30)	t	P value
HAMA score	8.88 ± 1.87	12.1 ± 3.27	-4.69	< 0.05
HAMD score	7.37 ± 1.41	11.79 ± 2.77	-7.79	< 0.05

HAMA: The Hamilton Anxiety Rating Scale; HAMD: The Hamilton Depression Rating Scale.

DISCUSSION

Gastrointestinal surgery has long been a focus of the medical community[21]. However, the surgical process inevitably causes trauma to the patient. This trauma involves direct damage at the surgical site and systemic physiological and pathological reactions[22]. Notably, suppression of the patient’s immune function and weakening of wound healing ability owing to surgery have become key factors influencing postoperative recovery speed and therapeutic outcomes[23].

The results of this study demonstrated that a comprehensive nutritional support program significantly improved immune function, wound healing, pain scores, psychological status, and duration of hospital stay in patients following gastrointestinal surgery. Specifically, WBC counts, CD4+ T cell ratio, and CD4+/CD8+ ratio of patients in the experimental group were significantly higher than those in the control group, whereas the CD8+ T cell ratio was significantly lower than that in the control group. This shows that comprehensive nutritional support can effectively enhance immune function in postoperative patients and reduce the risk of postoperative infection. This finding is consistent with those of previous studies and supports the importance of comprehensive nutritional support in the maintenance of immune function post-surgery. The wound infection rate in the experimental group was significantly lower than that in the control group, and the wound healing time was significantly shorter. This suggests that comprehensive nutritional support promotes wound healing and reduces the occurrence of infections. This may be because comprehensive nutritional support provides sufficient proteins, vitamins, and trace elements to promote collagen synthesis and tissue repair. Certain nutrients, such as vitamin C and zinc, play key roles in the wound healing process.

In addition, certain nutrients, such as glutamine and omega-3 fatty acids, are thought to exert immunomodulatory effects and can improve immune responses through a variety of mechanisms. Wound healing is a complex physiological process involving inflammatory responses, cell proliferation, and tissue remodeling. Malnutrition can slow the wound healing process and increase the risk of wound infection[24]. Adequate nutrients such as proteins, vitamin C, and zinc are essential for collagen synthesis and wound healing. Research shows that comprehensive nutritional support can significantly improve wound healing in patients following gastrointestinal surgery, reduce wound infection rates, and accelerate healing[25].

In terms of pain scores, VAS scores in the experimental group on postoperative days 3 and 7 were significantly lower than those in the control group. This suggests that comprehensive nutritional support not only improves the patient’s physiological state, but may also reduce pain perception by reducing inflammation and improving overall health. Certain nutrients such as omega-3 fatty acids are thought to have anti-inflammatory and analgesic effects, which may have contributed to the lower pain scores in the experimental group. The anxiety (HAMA) and depression (HAMD) scores of the experimental group were significantly lower than those of the control group. This demonstrates that comprehensive nutritional support can help improve the psychological state of patients and reduce postoperative anxiety and depression. Several studies have verified the relationship between malnutrition and mental health. Adequate nutritional intake can help stabilize mood, improve psychological resilience, and promote recovery. Regarding hospitalization time, the average duration of stay for patients in the experimental group was significantly shorter than that of the control group. This not only reflects the positive impact of comprehensive nutritional support on postoperative recovery, but also helps reduce pressure on medical resources and clinical costs.

Comprehensive nutritional support has a positive effect on postoperative patients through multiple mechanisms. First, comprehensive EN maintains intestinal barrier function by providing easily absorbed nutrients, reducing intestinal flora translocation, and reducing the occurrence of related infections. Second, PN supplements the necessary nutrients when EN is insufficient, ensuring that patients’ nutritional needs are fully met. In addition, specific nutrients such as glutamine and omega-3 fatty acids have immunomodulatory and anti-inflammatory effects, helping reduce postoperative inflammatory responses and promote immune function recovery. Based on the findings of this study, comprehensive nutritional support programs should be widely used in the clinical management of patients following gastrointestinal surgery. Specific measures include initiating EN early post-surgery, combined with PN supplementation, regular monitoring of nutritional status and biochemical indicators, and adjusting nutrition plans as needed. Additionally, for patients at risk of malnutrition, nutritional assessments and interventions should be performed before surgery to optimize postoperative recovery.

Although this study yielded clinically meaningful results, it had certain limitations. First, this was a retrospective study and may have had selection and information biases. Second, the sample size was small, and the findings may have been affected by inter-individual differences. Future studies should aim to expand the sample size and adopt a prospective randomized controlled trial design to further verify the effectiveness and safety of comprehensive nutritional support programs. Research should also explore the effects of different comprehensive nutritional support programs for various types of gastrointestinal surgeries and optimize these programs accordingly. In addition, the mechanisms of action of specific nutrients in postoperative recovery should be investigated further to reveal their effects on immune function, inflammatory responses, and wound healing. Through multicenter, large-scale prospective studies, more reliable evidence can be obtained to promote the standardized and individualized development of comprehensive postoperative nutritional support.

CONCLUSION

This study demonstrated that a comprehensive nutritional support program has significant advantages in the rehabilitation of patients following gastrointestinal surgery. Such support not only improves immune function and wound healing, but also significantly reduces postoperative pain and psychological stress, and shortens the duration of hospital stay. Therefore, comprehensive nutritional support should be widely implemented in clinical practice to improve the overall recovery in patients after gastrointestinal surgery. Future studies should focus on optimizing these comprehensive nutritional support programs, elucidating the mechanisms of action, and providing patients with more precise and effective comprehensive nutritional interventions.