Taicang No. 1 People’s Hospital, Taicang, Jiangsu 215400, China
Acute myocardial infarction (AMI) patients may suffer from constipation for various reasons. Constipation may lead to flatulence in enteric cavity, raised diaphragm, reflex affected heart rate and coronary blood flow. Meanwhile, venous thrombus is suctioned during forced defecation to easily cause pulmonary embolism. The pressure in right atrium is increased and the blood flow rate during diastole is decreased, resulting in relative coronary ischemia in narrow lumen and increased anaerobic metabolism of heart muscle. All these induce severe arrhythmia and paroxysmal dyspnea, and even result in death . Hence, keeping bowels open is significant to the treatment and rehabilitation of AMI patients. This paper presents the study.
Constipation refers to the difficulty in defecation as feces stay in enteric cavity for too long and become hard as their water content is excessively absorbed. Constipation is not a disease, but a syndrome common to various diseases. Pan Guozong et al. carried out a questionnaire survey on 2,500 permanent residents at age 18-70 in Beijing, detecting 2.11% males and 9.68% females with chronic constipation. The incidence goes up as age increases .
2.1 The occurrence of constipation relates to the position and range of myocardial infarction. For instance, constipation happens very often to patients with extensive anterior myocardial infarction. If AMI happens at that position, sympathetic nerves are easily agitated to increase heart rate, worsen myocardial ischemia and hypoxia, resulting in obvious chest pain. Thus, patients must use anodyne (e.g. morphine) relatively more often for the pain. However, this kind of medication has its side effects.
2.2. After AMI, patients often suffer from autonomous nerve function disorder that inhibits regular bowel movements due to severe pain, severe strain and fear. Some drugs are taken, e.g. painkillers (morphine and papaverine, etc.), neural blockers and anticholinergic drugs. Anodyne (e.g. morphine) will agitate the smooth muscle of the gastrointestinal tract, cause the contraction of sphincter, decrease the excretion of digestive juices, and slow down the peristalsis of intestines, resulting in difficulty in defecation. Thus, attention must be paid to this cause.
2.3 For change in way of defecation, most patients are not used to defecation while on the bed. So they often control the bowel movements intentionally, causing constipation as feces stay in their bowel for too long time and are dried due to excessive loss of water.
2.4 Due to myocardial ischemia, hypoxia and putrescence, heart function declines obviously, and heart stroke volume decreases, often resulting in digestive hypofunction and less food intake. Especially, patients take in too little cellulose and water, resulting in insufficient contents in enteric cavity, so rectal mucosa cannot be effectively agitated to cause defecation reflex.
2.5 Long-term bed rest weakens gastrointestinal peristalsis, and causes loose and weak belly muscles and diaphragm, so intra-abdominal pressure is insufficient during bowel movements, making it difficult to defecate.
2.6 Due to gradual ageing of organisms, middle-aged and the elderly experience muscular dystrophy in the colon and rectum, lowered tonus of intestines and poor bowel movements. In addition to decreased secretion of gastrointestinal mucosa, feces are easily caked to cause constipation.
Acute myocardial infarction patients may suffer from some adverse consequences due to straining during defecation. Heart muscle experiences degeneration necrosis and rupture 6h after AMI, starts growth of granulation 1 week later, and gradually develops scar 2 weeks later. At this time, if the heart is overburdened for any reasons, patients may suffer from serious complications or die abruptly. The adverse effects are as follows:
1) Straining during defecation increases blood pressure, heart rate, pulsation and burden on heart, normally five times higher than normal bowel movements, which is extremely harmful to myocardial infraction patients.
2) For straining during defecation, the pressure in right atrium is increased and the blood flow rate during diastole is decreased due to excessive breath-holding. These increase the burden on the heart, resulting in heart failure and severe arrhythmia, fainting and even sudden death.
3) Long-term bed rest or heart failure slows down the blood flow of patients, resulting in thrombosis in deep veins of lower limbs and pelvic veins. If there is excessive straining during defecation, neighboring thrombi in veins fall to block pulmonary arteries and cause serious complications, even death due to sudden cardiac arrest or ventricular fibrillation.
4) Long-term constipation may cause swelling stomach and rectal inflation, which raises diaphragm, leads to abrupt change of reflex affected heart rate and coronary blood flow, increases burden on heart and worsens the sickness. Acute myocardial infarction patients experience acute development, quick change, multiple complications and high mortality rate. No matter whether AMI patients are in acute phase or recovering, straining during defecation often induces angina, arrhythmia, carcinogenic shock and heart failure, and even results in sudden death .
4.1 Psychological nursing: Defecation is completed through nerve reflex; in other words, constipation is caused by anxiety, fear and other factors. Patients of AMI feel the fear and tension due to sudden attack and severe pain, and become indescribably anxious in a strange environment when detecting the alarm of the monitor. Hence, attention should be paid to psychological conditions of patients to help their adaptation to the environment as quickly as possible, so as to face the disease and cooperate in treatment with emotional stability and activeness.
4.2 Health education: The knowledge about AMI, importance of smooth defecation and dangers of straining during defecation is explained to a patient and his family. The most suitable time of defecation should be 15-30min after breakfast. At that time, defecation may easily establish a conditioned response and develop into a habit even after a long time.
4.2 Guidance regarding defecation on bed to patients: Due to change of environment and habitual way of defecation, most patients are not used to defecation on or near bed. At first, nurses should constantly and patiently explain the importance of defecation while on bed in order to gain the patient’s assistance. During defecation while on bed, a screen is placed to protect the privacy of patients. If the patient does not feel comfortable, the head of the bed can be raised by 20°-30° to make the patient feel more comfortable. During defecation, nurse should keep asking the patient to relax, exhale through open mouth, not to hold breath or strain. If necessary, the patient can place a nitroglycerin tablet or isosorbide dinitrade in mouth preventively, and be guarded to prevent any accident. Meanwhile, the patient’s privacy should be protected by the elimination of sound or odor. The patient should be provided with a device of suitable temperature during defecation and some items to keep him comfortable .
4.4 Nursing during meals: Suitable diets must be prepared according to the patient’s condition and with the cooperation of the patient and his family. In acute phase, the patient should mainly have low-salt, low-cholesterol, light and easily digestible foods, with smaller meals but more often. The patient should not eat too much, but have an appropriate quantity of protein, sufficient cellulose (vegetables and fruits, etc.) and vitamins. Moreover, about 1,000ml of water must be drunk every day. Drinking a glass of water with honey before sleep at night or a glass of boiled water with little salt before eating anything in the morning can facilitate bowel movements .
4.5 Massage for bowel movement: A bedridden patient should massage his abdomen periodically by overlapping and moving index fingers, middle fingers and ring fingers of two hands on the abdomen in the direction of intestines. Fingers are moved clockwise circularly from colon, transverse colon, descending colon to sigmoid colon. The massage should be performed two-three times a day, 15-20min each.
4.6 Taking laxatives: For instance, Phenolphthalein tablet, Fructus Cannabis Bolus or other laxatives can be taken every night. If a patient does not have bowel movement for three days but feels the desire to defecate, Enema Glycerini is used anally or 30ml paraffin oil is taken orally. If feces are too hard to be pushed out, finger gloves can be worn to take feces out immediately. In their research, Song Xia et al.  mixed 125ml (20%) compound mannitol injection with 125ml boiled water evenly, which was taken for two times at an interval of 1h. The results showed good effect of treating constipation.
4.7 Other nursing methods: As proven clinically, point massage can greatly alleviate constipation, reducing the proportion of laxative taken. If point massage is performed for a longer time, the symptoms of constipation are better alleviated and the effect lasts for longer time . Yu Lijun et al.  employed point massage to treat habitual constipation, while Song Chunyu et al.  treated constipation by pressing Tianshu point, which both achieved good effects. Auricular point pressing treatment can adjust the functional activity of body organs by stimulating ear points and adjusting channels, in order to keep balance and treat disease, so it is very helpful in treating constipation .
Avoidance of heavy work: Especially, patients should not move heavy objects. An old patient with coronary heart disease may experience myocardial infarction. Relaxation: A patient should live happily and calmly face everything. Cautions during bath: A patient should not take a bath immediately after or before meal. The temperature of the bath water should be close to the body temperature. A bath should not take too long. If a patient has serious coronary heart disease, he should be assisted during bath.
A patient should be guided with regards to meals based on the patient’s condition. A patient should eat coarse food grains and 80g fruits per day, and the dishes prepared for the patient should be cooked with vegetable oil or salad oil. A patient can have non-glutinous rice, noodles, egg white, Chinese cabbage, leek, spinach and other fresh vegetables every day. At lunch, appropriate protein can be taken. A patient should have lighter meals with more frequency, and have appropriate fruits including banana and apple before or after meal. A patient should eat less food that generate gas, and more enzyme foods that facilitate digestion.
Guidance for defecation: A patient is encouraged to have bowel movements periodically, and try defecation 10-15min after breakfast, as it is the easiest time for bowel reflex to arouse the desire of defecation.
Prevention and nursing for constipation: 1) Provide special nursing according to the procedures for AMI, pay close attention to observing the patient’s condition and offer reasonable meals. A patient should eat light foods that can be easily digested and generate little gas, as well as liquid and semi-liquid foods containing many vitamins and celluloses; 2) Remind the patient of not straining during defecation, as it may easily induce arrhythmia, heart failure and even sudden cardiac arrest; 3) Help a patient develop the habit of defecation while on bed; 4) Guarantee defecation of patient every day by offering senna tea twice a day, 2g each time, or an appropriate laxative in common cases or Xinqingning tablet in severe cases to prevent constipation, or employing Enema Glycerini or glycerol suppositories, or clyster for defecation; 5) Do not use too much anodyne, e.g. morphine; 6) Massage and exercise, press Tianshu point (2 inch near navel) during defecation, and practise abdominal breathing frequently to facilitate movements of the bowel; 7) Reduce the time of staying on bed as much as possible; 8) Allow a patient with complications to place 0.5 mg nitroglycerin tablet under the supervision of cardiogram monitor to guarantee safety during defecation.
Defecation is a basic physiological need of the human being and a necessity to sustaining life. To AMI patients, constipation has not only increased their pain, but also induces severe complications and even causes sudden death. Hence, it is necessary to strengthen the nursing for AMI patients with constipation, implement all kinds of nursing measures comprehensively, and provide focused nursing based on the condition of each patient, in order to guarantee the safety and comfort of patients.
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