What Is Oxygen Toxicity?

Oxygen is an indispensable substance for aerobic organisms to sustain life, but inhalation of oxygen over a certain pressure and time can have a harmful effect on the body. Oxygen poisoning refers to a condition manifested by pathological changes in the function and structure of certain systems or organs after the body inhales oxygen with a certain pressure for a certain period of time.

Basic Information

English name

oxygen toxicity

Visiting department

Emergency Department

Common causes

Oxygen inhalation over a certain pressure and time

Common symptoms

Cough, dyspnea, facial muscle twitching, sweating, salivation, nausea, vomiting, dizziness, palpitations and pale complexions, etc.

Causes of Oxygen Poisoning

Oxygen poisoning and oxygen inhalation time are closely related, the longer the time, the more prone to oxygen poisoning. Oxygen entering the body generates oxygen free radicals, which are extremely active, flowing around in the body, attacking and killing various cells, leading to metabolic and dysfunction of cells and organs, and can cause genetic mutations to induce cancer. Of course, when there is oxidation, there is anti-oxidation, which is a skill of the human body to protect itself. In a healthy person, the body's oxidation and antioxidant activities are in a dynamic balance.

Clinical manifestations of oxygen poisoning

Pulmonary oxygen poisoning

Similar to bronchial pneumonia. Its manifestations and general development process are as follows: Initially, it is similar to the symptoms of tracheal irritation caused by upper respiratory tract infections, such as post-sternal discomfort (irritation or burning sensation) with mild dry cough, which slowly increases; then there is post-sternal pain, and the pain gradually follows The bronchial tree spreads to the entire chest, even when inhaling; the pain gradually worsens, and an uncontrollable cough appears; breathing is also difficult at rest. Ending exposure in the early stages of symptoms, chest pain and cough can be alleviated within hours.

2. Seizure (brain type) oxygen poisoning

The manifestations of convulsive oxygen poisoning can be roughly divided into four consecutive stages:

(1) The incubation period is negatively related to the oxygen pressure in the inhaled air, but not linear. Increased oxygen pressure shortens the latency.

(2) Prodromal manifestations include: Facial muscle twitches, the most common being facial muscles and lip tremor; autonomic symptoms: sweating, salivation, nausea, vomiting, dizziness, palpitations, and pale complexion; Paresthesia : There may be reduced vision, hallucinations, hallucinations, hallucinations, oral odors, and numbness of the limbs; Mood abnormalities: irritability, anxiety, or euphoria; Extreme fatigue and dyspnea may occur at the end of the prodromal period, in rare cases There may be collapse.

(3) Convulsions occur soon after the prodromal period. Epilepsy-like generalized tonicity or paroxysmal convulsions, lasting about 2 minutes each time; Sometimes a short scream is issued before the attack, loss of consciousness, and sometimes incontinence.

(4) If the coma period is still in a high oxygen environment after convulsions, the coma period is entered. The experimental animals showed coma and unconsciousness, and occasionally a slight local convulsions, and the dyspnea gradually worsened, and then continued to breathe weakly until stopped. Even after the convulsions are released from the hyperbaric oxygen environment in a timely manner, there is still a period of confusion or mental and behavioral disturbances in the personnel. Generally, they can recover in 1 to 2 hours, and a few can sleep for hours. No obvious sequelae are left.

3. Ocular oxygen poisoning

Long-term inhalation of 70 8OkPaO ₂ can cause the disease very slowly, mainly manifested by retinal atrophy. Immature tissues are particularly sensitive to high partial pressure oxygen. Premature babies inhaled high partial pressure oxygen for too long in an incubator. The retina has extensive vascular obstruction, fibroblast infiltration, and fibroplasia after crystals, which can cause blindness. At 90 100kPaO ₂ , retinal detachment, atrophy, and damage to visual cells can occur within 72 hours; with time, harmful effects can accumulate.

Oxygen poisoning treatment

1. Treatment of oxygen poisoning during diving

(1) Quickly leave the high-pressure environment and promptly rise to the water when there are prodromal symptoms. When convulsions have occurred, the diver should be sent to the water in time for rescue, but the ascent speed should be controlled to prevent pulmonary barotrauma.

(2) After the water is discharged, remove the gear, rest in a supine position, keep quiet, pay attention to warmth, continue to observe, and prevent sudden convulsions.

(3) Anticonvulsant therapy should be used in patients with convulsions. Drugs that have a small effect on cardiopulmonary function should be selected. A 50% enema with 4% chloral hydrate can be administered subcutaneously after 2 hours. It can be applied repeatedly, no more than 4 times a day. Isobarbital can also be injected intramuscularly or intravenously. Because oxygen convulsions are often accompanied by a degree of lung injury, inhalation anesthetics are contraindicated.

2. Treatment of oxygen poisoning in pressurized cabin

(1) In the cabin that absorbs oxygen through the mask, quickly remove the mask, breathe the compressed air in the cabin, and decompress the air as usual.

(2) In a pure oxygen tank, first use compressed air for ventilation to reduce the partial pressure of oxygen in the tank, and then gradually decompress it out of the tank.

(3) When convulsions occur, the following points should be paid attention to: Prevent falls and injuries or bite the tongue, and use antispasmodics when necessary. Pay attention to the patient's breathing condition. During convulsions, throat convulsions and breath-holding are likely to occur. At this time, it is not possible to decompress to prevent lung pressure injury caused by glottal closure. Only after the rhythmic breathing is restored and the airway is unobstructed, decompression can be performed according to regulations. After leaving the hyperbaric oxygen environment, those with convulsions still have anticonvulsant treatment.

3. Treatment of various types of oxygen poisoning

(1) The principle of brain type treatment is sedation, anticonvulsant, hypnotic, and prevent head and tongue damage during convulsions. Can be given: Diazepam (Diazepam), slow intravenous injection; paraaldehyde, deep intramuscular injection, disabled patients with airway obstruction. Heart failure patients with heart-strengthening drugs.

(2) Those with mild lung type can recover within a few hours; severe cases use antibiotics to prevent lung infection and strengthen monitoring. Mainly supportive therapy promotes early absorption of lung lesions. If the patient has difficulty in gas exchange, hypoxia will occur if hyperbaric oxygen (HBO) is not used, and lung tissue will be further damaged by using HBO. Extracorporeal oxygenation using extracorporeal circulation device should be considered. To be restored.

(3) The eye type should regularly check the fundus during long-term oxygen inhalation treatment. Once the fundus vasospasm occurs, vision loss and blurring should be stopped. If the condition can not stop oxygen, the oxygen pressure should be reduced to below 5OkPa or given intermittent income of 2% to 4% CO ₂ (concentration under normal pressure) -oxygen mixture; and supportive therapy such as energy mixture should be given.

Oxygen poisoning prevention

Oxygen poisoning can be well prevented. On the one hand, it is necessary to strengthen the education of relevant personnel to make them aware of and alert to the symptoms of oxygen poisoning, especially the precursor symptoms. On the other hand, in the process of using oxygen, it is necessary to be strict Observe all operating rules. Specific preventive measures have the following aspects.

1. Oxygen susceptibility test. Subjects are allowed to inhale pure oxygen for 30 minutes at 280kPa. If preconvulsant symptoms occur, the oxygen sensitivity test is positive and cannot be selected as a diver or submarine crew.

2. Strictly control the pressure-time course of oxygen absorption.

3. Intermittent oxygen inhalation will be carried out in stages. Inhale air for 5 to 10 minutes between two oxygen inhalations. Facts have proven that a shorter interval can prevent oxygen poisoning that may be caused by a longer period of oxygen inhalation, thereby extending the total time course of oxygen inhalation and achieving the purpose of maximizing the use of oxygen.

4. Control the incidence factors.

5. Ensure that the oxygen supply device is in good condition and strictly operate the procedures.

6. Understand the daily life, work schedule and mental state of the diver or patient.

7. Minimize unnecessary physical activity when inhaling oxygen.

8. During the oxygen inhalation, medical staff should pay close attention so as to find the situation and deal with it in time.