Activated carbon not only has excellent adsorption performance and controllable pore structure within a certain range; it also has good biocompatibility and no toxic side effects. In the past, it was mainly used in clinical oral administration to stop diarrhea and prevent the absorption of poisons. With hemoperfusion adsorbents, artificial organs The development of adsorption preparations specifically adsorb middle molecular substances to treat various diseases, that is, use activated carbon as a carrier to adsorb some strong first-pass effects, short half-life, large damage to normal cells, and easy addiction (such as anti-cancer, chemotherapy, analgesia) ) To achieve the purpose of slow release of the drug and improvement of the therapeutic effect.
1. Oral removal of oral drug poisoning
In China, gastric lavage is widely used as a means to rescue poisoning. The American Society of Clinical Toxicology and the European Toxicology Center and the Association of Clinical Toxicology pointed out that gastric lavage was often used in poisoned patients in the past, but gastric lavage should not be used routinely. Experimental studies on poisoned patients have shown that the amount of markers removed by gastric lavage varies greatly and disappears over time. Research on the results of clinical treatment of overdose patients also clearly showed no beneficial effects. The risk of serious complications includes tissue hypoxia, arrhythmia, throat stenosis, perforation of the digestive tract and pharynx, water and electrolyte imbalance, and aspiration pneumonia. In general, the fatality rate of acute poisoning is less than 1%, and patients should not have dangerous complications due to gastric lavage abuse.
With the negative reports and evidence-based research on the risk of gastric lavage and vomiting, oral activated charcoal has become an effective means for patients to reduce absorption. As long as there are indications, activated charcoal should be used as soon as possible after taking the poison, and there is no need to induce vomiting or gastric lavage with emeticine in advance. Activated charcoal can bind to 45%~60% of toxins 30~60min after taking poison. 10g activated carbon should be used to absorb 1g of poison per person, and a dose of 50-100g is generally sufficient. Single-dose activated carbon treatment generally has no adverse reactions. In addition, there is a multi-dose activated charcoal method, that is, repeated oral administration of activated charcoal (at least 2 times) to speed up the excretion of absorbed drugs in the body. Drug poisoning with low volume distribution, low protein binding, long half-life, and pharmacokinetic characteristics of hepatoenteric circulation is a good indication for the application of multiple doses of activated carbon.
It has been reported that oral activated carbon has a significant effect in the treatment of ethanol and methanol poisoning. A survey on the treatment of boils in poisoned patients in Finland showed that 66.5% of the 226 poisoned patients were mostly ethanol poisoning (150 cases), and a small part was caused by overdose of drugs. 60% of these patients choose oral activated carbon treatment, and the treatment effect is obvious. Some scholars used oral activated carbon method to significantly reduce the mortality of mice poisoned by methanol.
In Hong Kong, activated charcoal itself is the emergency treatment option for poisoned patients. It is recommended that activated carbon should be used within 1 hour of ingestion of potentially toxic substances. Although there is no data to support or use it after 1 row, if there is no contraindication, the first few hours may be effective, especially for drugs with hepatoenteric circulation such as digoxin and theophylline. It can be administered orally or via colon lavage. If the patient takes a lethal dose, consider using multiple doses of activated carbon. Laxatives such as sorbitol or magnesium sulfate combined with activated carbon are currently considered to have some benefits or ineffectiveness.
2. Gastrointestinal lavage promotes the discharge of poisons
It has been reported that gastrointestinal lavage with activated charcoal should be used, activated charcoal should be given at a dose of 1:1, and then 20% mannitol 250mL for catharsis. The mechanism of activated charcoal gastrointestinal lavage and hemoperfusion rely on the adsorption of activated charcoal to remove toxins, without damage to liver, kidney function and hematopoietic function, especially for intestinal resecretion of sleeping pills poisoning. Hepato-enteric circulation drugs are repeatedly given activated charcoal for gastrointestinal lavage, which plays the role of intestinal dialysis. Compared with traditional gastric lavage, it removes poisons more cleanly and prevents the absorption of poisons, thereby reducing the effect of poisons on the body. Damage to the organs to prevent complications. Different from the commonly used whole bowel enema in foreign countries, the latter is to inject a large amount of polyethylene glycol solution quickly through the mouth until the rectal discharge becomes clear. Whole bowel lavage is especially useful for those poisons that are not absorbed by activated carbon (lithium, iron), drugs that stay in the intestines for a long time, such as some drug sustained-release tablets (such as calcium antagonists), and carriers who swallow large amounts of drugs . Polyethylene glycol is not absorbed and will not cause the patient's water and electrolyte disorders.
3. Hemoperfusion treatment of severe poisoning
Hemoperfusion is to remove poisons dissolved in the blood through the adsorption of the adsorbent in the perfusion tank. It is a recognized method to treat various drug poisonings to save patients' lives. The adsorbents commonly used clinically are mainly activated carbon and resin. The two have different adsorption capacities for different chemical substances. Activated carbon has strong adsorption capacity for non-polar and hydrophobic molecules, while resin has strong adsorption capacity for various lipophilic and hydrophobic substances such as bilirubin and stability. .
Summarize the application of hemoperfusion to poisoning: the molecular weight is large, the fat solubility is high, and the drugs and poisons that are easily combined with proteins in the body have a good removal effect. The drugs and poisons that can be absorbed by hemoperfusion include barbiturates, non-barbiturates, hypnotic sedatives, antipsychotics, antipyretic analgesics, cardiovascular drugs, herbicides, insecticides, etc. Indications for application: ①Patients whose blood concentration of drugs or toxicants reach a lethal dose; ②Severe clinical symptoms, such as hypotension, hypothermia, hypoxemia, heart failure, respiratory failure, etc.; ③With moderate brain insufficiency or coma Patients; ④Severe complications after poisoning, such as pneumonia and acute renal failure; ⑤Although there are no serious symptoms after poisoning, it is estimated that the poison will continue to be absorbed, and life-threatening will occur later, such as paraquat, methanol and other poisoning; ⑥ Patients with pre-existing liver disease or kidney disease are estimated to have detoxification dysfunction; ⑦The blood concentration of the drug or poison has not reached the lethal dose or the composition is unknown, although other measures are actively rescued, the condition is still progressively aggravated.
4. Extensive adsorption and specific adsorption in blood purification
The application of adsorbents in clinical medicine has developed into an important branch of biomedical engineering. At the same time, it also provides new treatment methods for clinical medicine, opening the door to many major and difficult diseases and even "incurable diseases". , Has become one of the important signs of hospital modernization. At present, the typical application of adsorbents in medicine is blood purification. Blood purification is an important method to remove blood poisons and pathogens. It is also related to the safety of blood and blood products, especially viral infections after blood transfusion. Generally concerned. Activated carbon as one of the adsorbents has a wide range, but the adsorption selectivity is low. In order to improve the clinical application of activated carbon, in recent years, domestic and foreign researches have been carried out on the forming technology, use mode and the improvement of the adsorption performance of activated carbon, and rapid progress has been made. Various hydrophilic gels have appeared one after another. , Activated carbon coated with polymer materials, carbon fiber, carbon film, carbon fiber fabric and other forms of medical activated carbon adsorbents. The improved activated carbon adsorbent has improved its performance to varying degrees.
At present, it is recognized that high-selectivity and regular removal of middle-molecular substances in the blood of patients has important clinical significance. Medium molecular substances are the main toxic substances that accumulate in the blood of patients with severe diseases such as uremia, hepatic encephalopathy and epidemic hemorrhagic fever. There are also many diseases that have increased levels of middle molecular substances, such as rheumatism, allergic infection, multiple organ failure, Aluminum hyperplasia has become a therapeutic area for blood purification. Hemoperfusion technology has developed from extensive adsorption to specific adsorption and immunoadsorption; the treatment of diseases has also been expanded due to new materials, from drug poisoning and pesticide poisoning to uremic molecular removal, adsorption of high blood lipids, high cholesterol, high bilirubin, etc. ; Treatment of refractory immune diseases such as systemic lupus erythematosus, rheumatoid arthritis, Guillain Barril, myasthenia gravis, multiple myeloma, as well as hemophilia and hepatitis B patients with surface antigen turned negative; it has been reported, Use hemoperfusion for thyroid dysfunction, schizophrenia, psoriasis and other diseases, chemotherapy adsorption, detoxification, etc.
5. Auxiliary surgery and interventional treatment of malignant tumors
Activated carbon is used to adsorb different anti-cancer drugs, such as mitomycin, arubicin, bleomycin, etc. Animal experiments have confirmed that under the same action conditions, its toxicity is far less than that of the aqueous formulation of anti-cancer drugs. Activated carbon has superior lymphatic tropism and adsorption properties, can adsorb anti-cancer drugs, and has functional slow-release characteristics. On the one hand, activated carbon adsorption anti-cancer drug preparations can be directed to distribute in lymph nodes and maintain a high concentration for a long time; on the other hand, activated carbon can stain the lymph nodes while migrating to the lymph nodes, thereby guiding lymph node removal surgery and removing metastatic lymph nodes. Because activated carbon has the characteristics of slow-release function, lymphatic tropism, local retention, adsorption to tumors and lymph nodes, and low toxic and side effects, its clinical application prospects are increasingly broad. The current clinical research focuses on making the diameter of the carbon particles more suitable for the transport requirements of the lymphatic system; the development of adsorbed anti-cancer drug formulations suitable for different malignant tumors and the doses of the combined anti-cancer drugs, reducing the occurrence of serious complications, and enabling targeted killing Dead cancer cells or resist lymphatic metastasis of cancer cells, opening up new areas for the treatment of malignant tumors.
Activated carbon particles are injected into the tumor and surrounding tissues for up to half a year, slowly releasing high concentrations of anticancer drugs to locally kill cancer cells and treat gastric cancer. Utilizing the blackening and adsorption stagnation effects of activated carbon, it can be used for radical gastric cancer surgery by injecting particulate activated carbon to visually guide the lymphatic track.
6. Develop new application areas
In recent years, new clinical applications of activated carbon have been continuously reported. In general anesthesia surgery, activated carbon was used to filter in a closed loop to absorb excess anesthetic gas drugs. The recovery time of the experimental group was significantly shorter than that of the control group. Japan chooses to use spherical activated carbon as an adsorption material AST-120 oral activated carbon (0.2~0.3mm in diameter) for experimental dogs with liver and kidney disorders, which prolongs their lifespan. This spherical activated carbon adsorbs the substances that cause obstacles and removes them from the body, thereby reducing the accumulation rate of poisons in the body. The results of clinical trials showed that the dialysis interval was extended to 9 months at the beginning of patients with kidney disease after taking it, and even some cases did not need dialysis after taking it for 2 years. At the same time, by adjusting the pore size and distribution of activated carbon, it can adsorb different harmful substances and bacteria. Therefore, the activated carbon particles in the chemotherapeutic drugs can be used to induce exogenous granulomas, and the metastases of gastric tumors can be tracked according to their different shape changes in CT scans.
