Carbon monoxide poisoning, commonly known as gas poisoning, is a harmful gas produced by the incomplete combustion of all carbon-containing substances, and the content in normal air is only 0.04 ppm. The affinity between CO and hemoglobin is about 200 times greater than that of oxygen. When CO enters the body, it combines with hemoglobin to form carboxyhemoglobin, which makes the hemoglobin lose its oxygen-carrying capacity and causes hypoxic poisoning in the body. The brain is the most sensitive to oxygen deprivation. Clinical manifestations 1. Mild poisoning: Patients show headache and dizziness, nausea and vomiting, deafness, panic and shortness of breath, general weakness, shivering and even urinary and fecal incontinence. There may be a brief loss of consciousness, but the duration is less than 30 minutes. 2. Moderate poisoning: The above symptoms are further aggravated, with a history of coma, and the duration of coma is 30 minutes to 4 hours, usually without accompanying symptoms. 3. Severe poisoning: (1) The patient is in a moderate or deep coma and the duration of coma is greater than 4 hours. (2) Regardless of the length of coma, there are one or more of the following concomitant diseases, such as cerebral edema, pulmonary edema, shock, toxic myocarditis, acute renal failure, limb crush injury, peripheral nerve injury, etc. Treatment Hyperbaric oxygen is the first choice of special treatment for CO poisoning. 1.Treatment timing: the earlier the hyperbaric oxygen treatment, the better, early treatment is conducive to the recovery of the disease. 2.Treatment times: 5 to 10 times for mild poisoning, 20 times for moderate moderate poisoning, and more than 30 times for severe poisoning, and stop only after checking the EEG is normal, otherwise late onset encephalopathy is likely to occur. 3.Therapeutic mechanism: (1) Hyperbaric oxygen can make the partial pressure of oxygen in the body several to ten times higher than normal, prompting the rapid dissociation of CO and hemoglobin, and restoring the oxygen-carrying capacity of hemoglobin from children. (2) Hyperbaric oxygen can rapidly increase blood oxygen content and improve hypoxia. (3) Hyperbaric oxygen can reduce the permeability of blood vessel wall and restore the sodium-potassium pump function of cell membrane, thus rapidly controlling cerebral edema. (4) Hyperbaric oxygen can rapidly correct the metabolic acidosis of tissues. (5) Hyperbaric oxygen has the effect of anti-shock. Prognosis After acute CO poisoning, there may be dizziness, memory loss, general weakness and reduced working ability, etc. It takes 1 to 3 months for mild poisoning, 3 to 6 months for moderate poisoning and more than 6 months for severe poisoning. V. Precautions 1. Avoid re-poisoning, multiple poisoning in a short period of time will aggravate the disease. 2.Avoid excessive sadness, anger and exertion, otherwise it will easily induce late onset encephalopathy. 3.Fewer activities and more rest in the early stage, so as not to increase oxygen consumption, which is not conducive to the recovery of the disease. 4.There is no restriction on diet, eat as much light diet, fruits and vegetables that are easy to digest as possible. 5.Prohibit or less smoking. Late onset encephalopathy of CO poisoning Late onset encephalopathy is a serious complication of CO poisoning, which is a series of abnormal neuropsychiatric behavior symptoms that appear after a period of “pseudo-healing” after the recovery of acute symptoms. Its incidence is about 10%, and most of them occur within one month after CO poisoning, especially in elderly people, long coma time, early treatment is not timely and incomplete, and more likely to recur. The recognized pathogenesis is due to demyelination, and the clinical manifestations are progressive dementia, small gait, unsteady walking, difficulty in eating, incontinence, and even bedridden coma. Treatment is mainly based on hyperbaric oxygen, and it usually takes 3 to 6 months to achieve self-care, which is time-consuming and economically burdensome, so the focus of treatment is to prevent relapse.