Artificial lung ventilation (ALV) was introduced into clinical practice in 1929 in order to “provide opportunities for all patients with impaired respiratory function to restore normal breathing”. This procedure has been used as a selective lung ventilation method in some pathological conditions for a long time.
Auxiliary ventilation allows the patient to maintain spontaneous breathing. Auxiliary lung ventilation can be considered as an interim stage between traditional artificial lung ventilation and adequate independent breathing.
The main task of anesthetic equipment of any complexity is to provide respiratory functions of the organism, i.e. effective gas exchange in conditions of separate or artificial respiration. Breathing circuit provides oxygen and anesthetics administration from anesthesia apparatus into the respiratory tract (lungs) of a patient and removal of this expiratory mixture. There are two main types of ventilator circuits: with and without the reversion of gas mixture. Reversion means full or partial rebreathing of the anesthetic gas that has already been exhaled. The simplest systems are nonrebreathing ones, which do not use the expiratory mixture again and depend on the level of fresh gas flow. Several models of such systems are described by Mapelson and are still used in some areas of anesthesiology, for example in pediatrics. However, in order to prevent the accumulation of CO2 in the circuit a flow of fresh gas is required, which exceeds minute pulmonary ventilation at least twice.