PAGES OF THE HISTORY OF GENERAL ANESTHESIA. PART 12

Abstract The twelfth part of the series of articles on the history of anesthesia is devoted to the history of the creation and improvement of the anesthesia machine, one of the most important tools used by anesthesiologists. Before the creation of anesthesia machines, inhalations of nitrous oxide and ether were carried out from a handkerchief or from a bag made of thick cloth to get a feeling of gaiety, slight intoxication and increased motor activity. The first anesthetic machines appeared following their public demonstration by Morton in 1846. These initial devices were simple inhalers based on the evaporation of the anesthetic agent. Their main problem was the loss of effectiveness with cooling. More complex inhalers were subsequently developed, in which the main difference was the possibility to provide more than one agent. Moreover, the concentration of the inhaled anesthetic was regulated for greater efficiency. At the beginning of the twentieth century, gas machines emerged, allowing the application of an anesthetic flow independent of the patient’s inspiratory effort. These machines incorporated technological advances such as flow meters, carbon dioxide absorption systems and fine adjustment vaporizers. In this period, in the field of thoracic surgery, intraoperative artificial ventilation began to be employed, which helped overcome the problem of pneumothorax associated with open pleura by applying positive pressure. From the 1930s, the gas machines were fitted with a ventilator, and by the 1950s this had become a basic component of the anesthesia system. Later still, in the 1980s, alarm and monitoring systems were incorporated, giving rise to the current generation of workstations. The 1st part of the series of articles is published in DSJ No. 73, the 2nd part in DSJ No. 76, the 3rd part in DSJ No. 77, the 4th part in DSJ No. 78, the 5th part in DSJ No. 79, the 6th part in DSJ No. 80, the 7th part in DSJ No. 82, the 8th part in DSJ No. 87, the 9th part in DSJ No. 88, the 10th part in DSJ No. 89, the 11th part in DSJ No. 93. To be continued.