In modern medicine, anesthesia describes, on the one hand, the state of insensibility that is sought to perform surgery, and, on the other hand, the method itself to bring about this state. For this purpose, special pain– and consciousness-inhibiting drugs, so-called anesthetics, are administered. Under general or local anesthesia, procedures can be performed on the patient in this way that were previously unimaginable.
Function of anesthesia in intensive care medicine.
The most common form of anesthesia is general anesthesia, also called narcosis. It affects the entire body and is used for the painless completion of surgical procedures. The state of anesthesia is achieved by intravenous or inhalational administration of drugs (anesthetics) and is characterized by loss of consciousness, containment of certain areas of the nervous system, muscle relaxation, and elimination of the sensation of pain. Normally, patients have memory lapses after awakening from anesthesia. This is referred to as amnesia. Local anesthesia (regional anesthesia) is a procedure for local anesthesia. The aim is merely to eliminate pain by acting on the nervous system with medication. The patient’s sense of consciousness remains unimpaired during local anesthesia. Local anesthesia is usually administered by injection in the area of the spinal cord, as is the case with peridural or spinal anesthesia. For this, surface anesthesia is usually performed beforehand by applying ointments, gels, sprays, or patches to the skin.
First attempts at anesthesiology
As early as the Middle Ages, priests and monks used alcohol and pain-relieving plants as part of their healing practices, in addition to prayers. In addition, there were a number of non-nasty techniques for numbing pain during treatment. These included bloodletting or compressing blood vessels to numb certain limbs. This method was very dangerous, as it could lead to infection and even unconsciousness. Despite the initially crude methods, anesthesia has always pursued only one goal: the freedom of the patient from pain during medical interventions. For this purpose, the anesthetic effect of plant extracts was known from early on. Some plant substances such as curare or opium (morphine) are still used in anesthesia today.
Beginnings of inhalational anesthesia.
In the early modern period, science gained new knowledge about gaseous particles. This knowledge was also used in anesthesia and intensive care medicine. The administration of gaseous anesthetics by inhalation through the patient’s lungs represented a new anesthetic procedure. However, a disadvantage of inhaled anesthesia was the slow accumulation of the gas in the organism. In addition, the body needed just as much time to recover from the anesthesia. Laughing gas, chloroform and ether were the first gaseous anesthetics to be used in anesthesia. Laughing gas was one of the first gaseous substances, which was initially consumed as an intoxicant and stimulant. In the late 19th century, the first attempts were made to use nitrous oxide as an anesthetic in dentistry. Chloroform was mainly used in obstetrics. However, chloroform has a very toxic and highly explosive property, from which many patients died.
Advantages and disadvantages of ether as an anesthetic.
Even at low concentrations, ether could provide adequate analgesia. In narcotic doses of this anesthetic, muscle relaxation of the patient occurred, but without severe respiratory depression. This created good surgical conditions during anesthesia. Although ether as an anesthetic was less dangerous than chloroform, this anesthetic drug also had health-endangering properties. Anesthesia with ether severely irritated patients’ airways. In addition, the newly discovered gaseous anesthetic caused vomiting and a strong urge to cough. In the worst case, anesthesia induced by inhalation of ether could lead to respiratory arrest. Nevertheless, the first successful ether anesthesia in history was performed in 1846 to treat a mandibular tumor in Boston. Only a few months later, ether was also used as an anesthetic during a transfemoral amputation in London.Since then, ether has become known worldwide as an anesthetic for inducing inhalation anesthesia.
Intravenous anesthesia
The administration of analgesic drugs via the vein has been known since the invention of the syringe and thus long before the development of anesthesia. As early as the 17th century, intravenous anesthesia using opium had been tried on dogs. Nevertheless, intravenous anesthesia for analgesia did not find its way into medicine until 1946.
Advantages of intravenous anesthesia
Gaseous anesthetics have the property of simultaneously eliminating all four components of anesthesia, namely consciousness, pain, muscle activity, and the autonomic stress responses. That is why inhalational anesthesia, i.e., anesthetizing the patient by inhalation of gases such as nitrous oxide, chloroform, or ether, was difficult to control. The intravenous method of modern anesthesia allows each component to be switched off individually. As a result, the administration of anesthetic drugs can be tailored to the individual patient. Thus, the administration of anesthesia is greatly facilitated.
Anesthetic procedures today
With the inclusion of “specialist in anesthesia” in the Medical Professional Code in Germany in 1953, anesthesia was officially recognized as an independent medical specialty. Many of the opiates and hypnotics introduced in the course of the following years, such as fentanyl, bupivacaine, midazolam, sevoflurane, remifentanil and propofol, are now important anesthetics in intensive care medicine and pain therapy. The development of synthetic drugs now enables specialists and anesthesiologists to accurately dose anesthetic agents. Dangerous incidents during surgery are thus becoming increasingly rare. In the meantime, anesthesia has advanced to the point where medical procedures can be performed without pain. Whereas it was sometimes necessary to make a tracheotomy to induce inhalational anesthesia, nowadays the breathing tube is inserted directly into the mouth or nasal cavity. This method is not only gentler but also associated with a lower risk of infection.
Rules for successful anesthesia
As before, anesthesia is interested in expanding its anesthetic procedures for the benefit of the patient. Nevertheless, every anesthesia is associated with risk. That’s why you should follow these rules:
- Be fasting before any anesthesia.
- Comply with the anesthesiologist’s instructions.
- Read your anesthesiologist’s information sheet carefully.
- Inform your anesthesiologist about any (pre-)diseases of the cardiovascular system or infections.
- Only expose your body to anesthesia when medically necessary.
