Anaesthetic gas

Anaesthetic gases are anaesthetics that are administered via the respiratory tract and are distributed in the blood via the lungs. The substances can be divided into two different groups. On the one hand, the substances that are gaseous at room temperature, nitrous oxide and xenon, and on the other hand the so-called volatile anaesthetics, which are in liquid form but can also be administered via the respiratory tract using a gasifier.

The drugs of this group commonly used in Germany are isoflurane, sevoflurane and desflurane. Nitrous oxide or in general parlance laughing gas is an inhaled anaesthetic which also has a pain-relieving effect. In medicine, the use of laughing gas is declining.

It is often used in combination with other anaesthetics. In dentistry, it continues to play an important role as a sedative, for example in anxious patients or children. When used properly, nitrous oxide has few side effects.

Intravenously administered anaesthetics

In most cases, a combination of different groups of active ingredients is used for an anaesthetic. Under certain circumstances, however, it can also happen that only intravenously administered drugs are used for anesthesia (total intravenous anesthesia = TIVA).Reasons for this can be an intolerance to anaesthetic gases, or known overreactions to other drugs. In the substance group of intravenously administered anaesthetics, a distinction is made between different active substances that have different influences on the body during the limitation of consciousness.

Before the anaesthesia is induced with the help of these drugs, an intravenous access must be made. The substances are then injected into the vein with the help of modern syringe pumps. The use of these syringe pumps enables the most precise administration of the substances, which is a considerable advantage due to the not inconsiderable effects in the case of overdose.

The so-called hypnotics (sleeping pills) are responsible for the loss of consciousness. The drugs used are usually propofol (phenol derivative (diisopropylphenol, in oily suspension)) or thiopental (group of barbiturates). They provide for the sleeping phase during anaesthesia.

However, they alone would not be sufficient for anaesthesia, as they have only a minor muscle relaxing function and no analgesic effect. For the analgesic effect, highly effective substances are given, which fall into the substance group of opioids. The advantage, apart from their analgesic effect, is the simultaneous attenuation of the vegetative reflexes and causing a memory gap (amnesia) after the procedure.

As some anaesthetics can cause severe nightmares, this memory gap is intentional and advantageous. Finally, muscle relaxants are part of the intravenously administered anaesthetics. These drugs prevent the impulses from being passed from the brain to the muscle, thus causing reversible paralysis.

Muscle relaxants are not necessary for every operation, but they do facilitate intubation. Propofol belongs to the group of intravenous narcotics and is the standard drug used to induce anesthesia. It is also well suited for TIVA (total intravenous anesthesia).

It is introduced into the bloodstream through a vein and takes effect there after 30-40 seconds for a duration of 5-8 minutes. It is administered continuously during an operation. Propofol leads to loss of consciousness in the body.

Moreover, it has an “amnesic” effect, which means that after the operation there is no memory of the period during which the drug was administered. In addition, it weakens the respiratory reflexes in the throat, which is favorable for anesthesia, leads to a drop in blood pressure and reduces the risk of postoperative vomiting and nausea. The injection of Propofol is often perceived as painful, but waking up and feeling good after the anaesthetic is often described as pleasant.