Determination of the level of condensate by recording the noise level in the respiratory circuit of mechanical ventilation devices

Abstract. The method of determining the accumulation of condensate by registering the noise level in the respiratory circuit of ventilators is substantiated. According to the proposed method, the condition and performance of the apparatus is monitored during artificial lung ventilation and oxygen therapy. With hardware ventilation, an increasing turbulent flow of a water or gas stream is formed in the respiratory circuit, accompanied by an increase in the noise effect and vibration. An increase in the level of acoustic noise from fluctuations in the accumulation of condensate in gaseous media was recorded by an instrument for objective measurement of sound level — a sound level meter. Indicators of noise effects reached a higher level on the wet circuit (the presence of condensation droplets or accumulations of mucus) of the liquid compared with the indicators obtained on the “dry” breathing circuit. The difference in recorded noise levels reached 10 dB, and increased from 37,73 to 47,36 dB. Areas of the respiratory circuit with the greatest degree of narrowing of the lumen and critical accumulations of water condensate and mucus are a source of turbulence in the air flow and increased noise. In conditions of prolonged artificial ventilation of the lungs, the rate of humidified air-gas flow is constantly changing, especially with hardware modeling of the phases of inspiration and expiration, and an increase in temperature in the humidifier chamber. The proposed technique is designed to identify critical levels of water condensate in the apparatus breathing circuits by recording the intensity of the increase in noise level and choosing the rational mode of operation of medical equipment. Data on the emerging critical situation are displayed on the sound level meter screen and inform medical personnel about the need to rehabilitate the circuit of the artificial lung ventilation apparatus. The primary field of application is resuscitation and intensive care units, medical transport teams during in-hospital or inter-hospital transportation, and surgical operating rooms during inhalation anesthesia.