Disease cause of POGD in TCM In TCM, it is considered that there are three main etiologies of POGD: (1) Exterior pathogen invasion: 1) Surgical factors: Surgery can dispel pathogens and meanwhile impair the meridians, leading to blocked circulation of qi and blood. As a result, the zang-fu organs are affected due to the lack of nourishment, thus damaging qi, blood, and body fluids; while blood extravasate gives rise to blood stasis, blocking qi movement. 2) Anesthetic factors: Anesthetics act on the house of the original spirit, causing vital activity dysfunction and loss of vitality, eventually affecting spleen and stomach functions. 3) Temperature: The patient’s internal organs are exposed to the outside during the operation. Hence, the six pathogenic factors, especially the pathogenic wind-cold, directly invade the body to impair the transportation and transformation function of the spleen and stomach; 4) Circulatory management: Anesthetic and blood loss can induce intraoperative hypotension, gastrointestinal hypoperfusion, and insufficient blood perfusion, resulting in deficient qi and blood nourishment in zang-fu organs. (2) Spleen-stomach weakness: Patients with chronic diseases, especially those with cancer, suffer from spleen-stomach weakness due to long-term illness or long-term diet disorders and immobilization (bed rest). Consequently, they are unable to take in water or grain, transport or transform essence, ascend lucidity, or descend turbidity. Besides, they tend to suffer from intestinal tract obstruction caused by turbid qi stagnation and stomach qi ascending counterflow . (3) Emotional disorder: Preoperative fear, anxiety, and other adverse emotions can lead to liver-qi stagnation and emotional disorder. The disorder will transform into fire, consumes qi, and damages yin, thus injuring the essence qi. Besides, it will also cause liver depression to restrict the spleen, bringing about liver and spleen disharmony, which can lead to postoperative disorder of spleen and stomach transportation and transformation.

Pathogenesis of POGD in TCM POGD is a deficiency syndrome complicated by excess patterns, with deficiency in zang-fu organs, qi, and blood as the root, and blood stasis, qi stagnation, and phlegm retention as the branch. “The six fu-organs are unobstructed in function.” The disease involves the spleen, stomach, large intestine, and small intestine and meanwhile are closely associated with the heart, liver, gallbladder, and other zang-fu organs. The key pathogenesis is stomach descending dysfunction and fu-organ qi obstruction. The spleen and stomach, serving as the hub of qi movement of the body, manifest abdominal distension and pain if the middle energizer experiences qi obstruction. Stomach qi ascending counterflow leads to vomiting. Spleen transportation and transformation dysfunction induce water-dampness retention in the middle energizer, thus leading to diarrhea (“excessive dampness represents diarrhea”). The intestines cannot receive spleen and stomach qi to intake, digest, and excrete, thereby resulting in constipation, stuffiness, and fullness.

Syndrome differentiation of POGD in TCM A total of 5 common syndrome subtypes were identified: syndrome of liver depression and spleen deficiency, yang brightness fu-organ syndrome, syndrome of qi stagnation and blood stasis, spleen-stomach weakness syndrome, and syndrome of cold and heat in complexity. The identification process was based on the TCM theories of zang-fu organs and eight-principle syndrome differentiation, with reference to opinions regarding POGD syndrome differentiation from Consensus of Experts on Diagnosis and Treatment of Irritable Bowel Syndrome in TCM (2017) (issued by China Association of Chinese Medicine, Spleen and Stomach Disease Branch) and relevant literature. Besides, the results of consultation with experts were combined, and the syndrome factors and characteristics of this disease were also comprehensively analyzed. The diagnostic criteria of different syndromes are as follows: (1) Syndrome of liver depression and spleen deficiency Manifestations: abdominal distension, borborygmus, abdominal pain, hiccup, constipation or diarrhea, immediate diarrhea after abdominal pain and pain relief afterward, appetite loss, poor flatus passage, bitter taste in the mouth, vexation and irritability, frequent sighing, pale red tongue or red edge, thin yellow tongue coating, wiry pulse. (2) Yang brightness fu-organ syndrome (qi stagnation in fu organs) Manifestations: abdominal distension and pain around the navel with refusal to press, constipation or passing of flatus, nausea and vomiting, belching, dry and bitter mouth, thick yellow and dry tongue coating with a prickly edge (sometimes even scorched, dry, and cracked coating), deep, slow, and excess or slippery and rapid pulse. (3) Syndrome of qi stagnation and blood stasis Manifestations: No flatus, constipation, abdominal distension, pain in chest and rib-side with refusal to press, stuffiness and fullness in the chest and rib-side, nausea and vomiting, poor appetite, dry stool, pale and dark tongue with petechiae or ecchymosis, wiry and/or astringent pulse. (4) Spleen-stomach weakness syndrome Manifestations: Dull pain in the gastric cavity with a preference for warmth and pressure, distension and fullness, poor appetite, poor defecation, fatigue, weak breathing, laziness for speech, limb weakness, spontaneous sweating, pale red tongue, thin and white fur, deep and thready pulse. (5) Syndrome of cold and heat in complexity Manifestations: Stuffiness and fullness in epigastrium, which is soft and painless when pressed; vomiting, thirst, and vexation; epigastric discomfort, borborygmus, and diarrhea; abdominal distension, dry and bitter mouth, pale red tongue, white or yellow greasy tongue coating; wiry and thready or wiry and slippery pulse.

Diagnosis of POGD in Western medicine Following selective auxiliary examinations based on the detailed medical history and physical examination, POGD can be diagnosed if vital organ diseases and metabolic abnormalities are excluded. The diagnostic criteria in this guideline are primarily in accordance with the Consensus of Experts on Diagnosis and Treatment of Irritable Bowel Syndrome in TCM (2017) issued by the Spleen and Stomach Disease Branch of China Association of Chinese Medicine, Rome IV diagnostic criteria for functional gastrointestinal disorders, and relevant literature. Diagnostic criteria for POGD 1) Medical history: Patients underwent anesthesia and surgery, without a history of preoperative functional gastrointestinal disorders; 2) Symptoms: Postoperative gastrointestinal symptoms, including nausea, vomiting, abdominal distension, abdominal pain, constipation, diarrhea, etc. 3) Physical signs: Through inspection of physical examination, abdominal asymmetric distension was observed and tenderness might appear after palpation in the abdomen; hyperactive or diminished bowel sounds were heard on auscultation; 4) Electrogastrogram: Electrogastrogram denoted abnormal gastrointestinal electrical rhythms such as bradygastria or tachygastria; 5) Imaging manifestations: Gastroparesis syndrome ultrasound or X-ray examinations exhibit no gastric peristalsis, weak peristalsis, or ineffective peristalsis; the stomach contains copious fluid accumulation; postoperative paralytic ileus manifests multiple dilated bowel loops and gas-liquid interfaces in erect or lateral positions of X-ray. Note: Preliminary diagnosis can be made if 1) 2) 3) are met, and the diagnosis and subtype can be confirmed when 4) or 5) is also satisfied.

Diagnosis of POGD in TCM As the term for “POGD” is not clearly documented in TCM, we have formulated TCM diagnostic criteria of POGD according to the disease definitions in TCM. (1)Patients underwent anesthesia and surgery without a history of functional gastrointestinal disorders; (2)Patients who manifest postoperative symptoms such as abdominal fullness, hiccup, nausea, vomiting, abdominal distension, abdominal pain, constipation, and diarrhea can be diagnosed to have “stuffiness and fullness”, “nausea”, “vomiting”, “intestine impediment”, “intestinal obstruction”, “constipation”, or “diarrhea” in TCM.

Preoperatively, TCM mental therapy is recommended to facilitate early postoperative gastrointestinal function recovery. (1B)

Acupuncture, acupoint pressing, auricular point therapy, electrical stimulation of acupoints, and music therapy are recommended to improve mood disorders like preoperative fear and anxiety. (1B)

It is recommended to apply acupoint stimulation techniques such as TEAS, electroacupuncture, auricular acupressure, and acupoint application before abdominal and spinal surgery to prevent POGD. (1B)

For special operations or patients requiring preoperative bowel preparation, oral administration/enemas of Chinese medicine prescriptions such as Major Purgative Decoction, Minor Purgative Decoction and their modified prescriptions, Bowel Cleansing Formulas are recommended to prevent and treat POGD. (2C)

Intraoperative general acupuncture or electroacupuncture is recommended to prevent POGD. (1B)