A ventilator includes an enclosure, a tubing configured to receive an input gas, and a flow outlet airline in fluid communication with the tubing. The flow outlet airline includes an airline outlet. The ventilator further includes a breath detection airline including an airline inlet. The airline inlet is separated from the airline outlet of the flow outline airline. The ventilator further includes a pressure sensor in direct fluid communication with the breath detection airline. The ventilator includes a controller in electronic communication with the pressure sensor and an internal oxygen concentrator in fluid communication with the tubing. The internal oxygen concentrator is entirely disposed inside the enclosure.