The four techniques of on-site first aid are

1. Oxygen intake

(1)Conversion method of oxygen concentration and oxygen flow: oxygen concentration (%)=21+4×oxygen flow (L/min).

(2) four defenses: fire, shock, heat, oil, to prevent explosions and combustion fires.

(3) When inhaling oxygen, first adjust the oxygen flow and then insert the nasal cannula; when stopping oxygen, first remove the nasal cannula and then turn off the switch, all in order to avoid damage to the lungs if a large amount of oxygen enters the respiratory tract in case of an error in the switch.

2. Suction

(1)Negative pressure of the suction device when suctioning: adult 40.0-53.3kPa (300-400mmHg), pediatric

(2)Methods: rotate left and right, lifting upward, and the suction time should be less than 15 seconds each time.

(3) Precautions: before and after sputum suction, increase oxygen concentration to prevent hypoxia; when the liquid in the reservoir bottle reaches 2/3 full, pour it out in time; change the suction material once or twice a day, and change the suction tube every time; tracheotomy patients: suction at the tracheotomy first, and then suction the oral and nasal cavities.

3. Gastric lavage

(1) each drug poisoning detoxification contraindication: trichlorfon + alkaline drugs (2% ~ 4% sodium bicarbonate) = dichlorvos; rodenticides (zinc phosphide) + eggs, milk = stronger toxicity, available copper sulfate; barbiturates + magnesium sulfate = aggravation of central inhibition, available sodium sulfate; Rogaine (1059, 1605, 4049) + potassium permanganate = stronger toxicity, available 2% ~ 4049, available sodium sulfate. More toxic, available 2% to 4% sodium bicarbonate (except for Lego, all other poisonings can be detoxified with potassium permanganate).

(2) Contraindications: strong corrosive poisons (such as strong acid, strong alkali), in order to avoid perforation; cirrhosis with esophagogastric fundal varices, thoracic aortic aneurysm, recent upper gastrointestinal hemorrhage and gastric perforation, gastric cancer, etc., so as not to cause hemorrhage; coma patients gastric lavage should be cautious, in order not to cause asphyxia.

(3) gastric fluid when the poisonous substance is unknown, how to deal with: should be the first choice of warm boiled water or saline gastric lavage, to be clear after the nature of the poisonous substance, and then the use of antagonist gastric lavage.

(4)Gastric lavage is most effective within 4 to 6 hours after taking poison, and the volume of each lavage should be 300 to 500 ml, not more than 500 ml at a time.

4. Cardiopulmonary resuscitation

(1)The most important clinical manifestations for determining the cardiac arrest: the loss of consciousness and disappearance of the aortic pulsation.

(2) Irreversible damage to brain tissue occurs 4 to 6 minutes after circulatory arrest.