What is an Inhalation Anesthetic?

Inhalation anesthetics are a type of general anesthetic that enter the lungs through the respiratory tract. Ether is the most commonly used inhalation anesthetic, allowing patients to undergo surgery without pain. However, some side effects have also been observed during its application. Nowadays, new inhalation anesthetics with smaller dosages and fewer side effects are available. Commonly used inhalation anesthetics mainly include isoflurane and sevoflurane.

Inhalation anesthetics refer to drugs that are inhaled into the lungs through the respiratory tract to produce central inhibition and complete surgery. The main anesthetics include nitrous oxide, enflurane, isoflurane, sevoflurane, and desflurane. Laughing gas, which was used a long time ago, also belongs to inhalation anesthetics. Currently, isoflurane and sevoflurane are more commonly used. Sevoflurane has a refreshing scent with a special fruity aroma, which is more acceptable to children and is currently widely used. Enflurane and isoflurane have a special irritating odor and are not easy to be used in children, but can be used for general inhalation anesthesia after the patient falls asleep.

1. Ether anesthetic: Ether at anesthetic concentrations has little effect on respiratory function and blood pressure, and also has low toxicity to the heart, liver, and kidneys. Ether also has a curare-like effect, resulting in strong muscle relaxation. However, this drug has a long induction and recovery period, and anesthesia accidents are prone to occur.

2. Fluorinated anesthetics: Fluorinated anesthetics have strong anesthetic effects and short induction periods. They have weak muscle relaxation and analgesic effects; they can dilate blood vessels in the brain, increase intracranial pressure; increase the sensitivity of the myocardium to catecholamines, and induce arrhythmias. Repeated use can occasionally lead to hepatitis or liver necrosis. Uterine muscle relaxation often leads to postpartum hemorrhage, and it is contraindicated in patients with difficult childbirth or cesarean section.

3. Enflurane and isoflurane: Enflurane and isoflurane are isomers with stable, rapid, and comfortable anesthetic induction, fast recovery, good muscle relaxation, and no increase in the sensitivity of the myocardium to catecholamines. Repeated use has no significant side effects on the liver, but occasionally causes nausea and vomiting. They are currently the more commonly used inhalation anesthetics.

4. Nitrous oxide: Nitrous oxide is not metabolized in the body and is mostly exhaled through the lungs in its original form. It has low lipid solubility, a short induction period, and rapid recovery, providing a comfortable and pleasant feeling for patients. It has strong analgesic effects and has no adverse effects on respiratory, liver, and kidney functions; it has a slight inhibitory effect on the myocardium.