A safety guard system for N₂O - O₂ gas flow rate adjustment in general anesthesia machine

An anesthesia machine is a main equipment used to deliver anesthetic drug vapors to patient during surgery procedures in the operating room. This equipment supplies a mixture of nitrous oxide and oxygen gas into breathing circuit through a flow adjustment module. In this module, a safety guard system must always be essentially installed inorder to prevent hypoxic events resulting from unintended delivery of low oxygen concentration. This module commonly designed basing on two concepts as a link-25 system with a mechanical linkage chain or an electronically controlled linkage inorder to ensure that each gas mixture contains at least 25 percentage of oxygen gas before being delivered to patient. Then, it is essential that all users, especially novice staff, should fully aware and understand this critical safety feature. In this paper, we present a simplified anesthesia model using effective simulation tools, intended to serve as an accessible educational aid to promoting and enhance an understanding of both linkage safety systems. The focusing is on a flow adjustment of nitrous oxide and oxygen gas flow rate specifically their increasing and decreasing within the flow adjustment module. Gas flow rate adjustment is performed in two main scenarios as adjust each gas flow rate separately and adjust the total gas flow rate. As a preliminary, the flow waveform of each gas flow rate controlled by our flow adjustment model show an effective response and be able to use as a routine practice for new practitioner inorder to understand the 75-25 percentage proportional gas flow concept of the hypoxic safety guard system in general anesthesia machine. For further study, complete anesthesia machine model including bellow ventilator for controlled ventilation during operation will be added in the near future.