Negative pressure absorption device and respiratory anesthesia machine

The utility model is applicable to the field of medical equipment, and provides a negative pressure absorption device and a respiratory anaesthesia machine, the negative pressure absorption device comprises a Laval nozzle, a first receiving chamber, a diffusion channel and a first injection port communicated with the first receiving chamber which are communicated in sequence; the end, close to the diffusion channel, of the first receiving chamber is provided with a flat inner wall. According to the negative pressure absorption device provided by the embodiment of the utility model, the first receiving chamber is provided with the flat inner wall close to the switching channel, and a flow guide component extending into the second receiving chamber from the switching channel is canceled, so that the phenomenon that gas entering the second receiving chamber from the second injection port is blocked by the flow guide component to form a dead cavity is avoided; therefore, energy loss caused by a dead cavity is red