The connection method between the anesthesia mask and the breathing circuit is directly related to the stability of gas delivery, and its core lies in the tightness of the connection. If a snap-on connection is used, the bite depth and uniformity of the snap will affect the sealing. When the snap is not fully fastened or the force is uneven, a small gap will appear at the connection, causing anesthetic gas leakage. Leakage will not only reduce the actual gas concentration entering the patient's respiratory tract, but also increase the pressure fluctuation in the circuit, resulting in unstable delivery volume. Especially during high-pressure ventilation, the leakage problem will be more obvious, directly affecting the anesthesia effect.
The adaptability of the connection interface is the basis for ensuring stable delivery. The specifications of the anesthesia mask and breathing circuit interfaces of different brands may vary. If the interface size does not match, even if it is forced to connect, continuous leakage will occur due to excessive gaps. Some interfaces adopt a conical design and rely on friction to achieve sealing. If the taper matching accuracy is insufficient, gas leakage will occur from the side, resulting in the inability to maintain stable pressure in the circuit. This unstable pressure will cause the tidal volume to fluctuate, affecting the patient's ventilation effect and increasing the difficulty of anesthesia management.
The tightness of the rotary connection has a direct impact on gas delivery. When the connection is too loose, the weight of the breathing circuit will pull the interface, causing the anesthesia mask to shift, and the gap at the connection will increase, causing gas leakage; if the connection is too tight, the interface may be deformed, destroying the flatness of the sealing surface, and also causing leakage. In addition, an overly tight connection will increase the difficulty of disassembly, which may delay the replacement of the anesthesia mask in an emergency. The appropriate tightness can ensure the seal while allowing the anesthesia mask to have a certain amount of movement space, adapt to changes in the patient's body position, and maintain the continuity of gas delivery.
The use of the flexible connecting tube will change the stability of gas flow. When the breathing circuit is connected to the anesthesia mask through a flexible bellows, the twisting or over-stretching of the bellows will increase the gas flow resistance and cause pressure fluctuations in the circuit. Especially when the patient's head and neck are moving, if the bellows is compressed or bent, it will instantly block the gas passage and cause ventilation interruption. When using a rigid connection tube, although it can reduce resistance changes, it lacks buffering. Changes in the patient's position may be directly transmitted to the anesthesia mask, causing the anesthesia mask to temporarily fail to seal and affect the stability of gas delivery.
The pressure resistance of the connection part is crucial during high-pressure ventilation. High-pressure ventilation is sometimes required during anesthesia. If the connection method is not pressure-resistant enough, such as using a plastic buckle connection, the interface may be separated or deformed under high pressure, resulting in a large amount of gas leakage and failure to reach the preset ventilation pressure. The metal lock or threaded connection method has stronger pressure resistance and can maintain a stable connection under high pressure, ensuring that the gas is delivered according to the set parameters and avoiding the impact of insufficient pressure on the patient's oxygenation.
The concentricity of the connection will affect the smoothness of gas flow. When the center axis of the anesthesia mask interface and the breathing circuit interface deviates, the gas will form turbulence at the connection. The resistance generated by the turbulence will consume part of the pressure, resulting in unstable gas flow rate entering the anesthesia mask. This turbulence may also cause the accumulated water in the circuit to be impacted to the anesthesia mask side, affecting the dryness of the gas. At the same time, the vibration caused by the turbulence will be transmitted to the anesthesia mask, causing the anesthesia mask to shift slightly, indirectly affecting the sealing effect and further exacerbating the instability of delivery.
The automatic locking function of the quick-connect device is of special significance for stable delivery in emergency situations. High-quality quick-connect devices can automatically complete the locking when docking, ensuring the sealing of the connection at the moment and avoiding leakage caused by improper manual operation. However, poor-performing quick-connect devices may fail to lock, especially after repeated use, the spring elasticity decreases, and continuous sealing cannot be guaranteed, resulting in intermittent gas delivery. In emergency or rapid induction of anesthesia, this unstable connection may delay treatment and increase the risk to patients.
Regular maintenance has a long-term impact on the stability of the connection. If the connection interface is not cleaned for a long time, dust, secretions or lubricant residues will accumulate on the surface. These impurities will destroy the fit of the sealing surface and cause gas leakage. In addition, if the sealing ring at the interface is aged, cracked or deformed, the sealing function will be lost directly, and no matter which connection method is used, the stable gas transmission cannot be guaranteed. Therefore, regular inspection and replacement of damaged sealing rings and cleaning of the interface surface are important measures to maintain connection stability.
