Devices, systems, and methods for inflation are provided. Inflation devices include a housing, a compressed gas canister disposed therein, a syringe disposed within the housing, a plunger slidably disposed in the syringe having an unloaded position and a loaded position relative to the syringe., a puncture mechanism disposed within the housing and configured to open a fluid path between the compressed gas canister and the syringe, and a positive pressure mechanism disposed within the housing and operably coupled to the syringe. Engagement of the puncture mechanism puts the syringe into fluid communication with the compressed gas canister such that gas contained therein loads into the syringe and the plunger moves from the unloaded position and the loaded position. The positive pressure mechanism is configured to maintain the gas within the syringe at a positive pressure relative to ambient pressure in order to prevent air from entering the syringe after loading.提供了用於膨脹的裝置、系統和方法。膨脹裝置包括殼體、安設在其中的壓縮氣體罐、安設在所述殼體內注射器、可滑動地安設在所述注射器中的柱塞，其相對於所述注射器具有未裝載位置和的裝載位置、安設在所述殼體內並被配置用於打開所述壓縮氣體罐和所述注射器之間的流體路徑的穿刺機構以及安設在所述殼體內並可操作地耦合至所述注射器的正壓力機構。所述穿刺機構的接合使所述注射器與所述壓縮氣體罐流體連通，使得包含在其中的氣體被裝載到所述注射器中，並且所述柱塞從所述未裝載位置移動到所述裝載位置。所述正壓力機構被配置用於將所述注射器內的所述氣體保持在相對於環境壓力的正壓力下，以防止空氣在裝載之後進入所述注射器。
