Urgent oxygen deliveries: Urgent deliveries occur mainly after discharge from a hospital or when a portable oxygen concentrator breaks down. It depends where the delivery needs to be done if OxygenWorldwide can arrange replacement oxygen immediately. It is advisable to do a FREE pré-registration for the OxygenWorldwide S.O.S Back-up service if one starts to travel with a portable concentrator (POC). This way one will know on forehand if and what type of oxygen equipment can be provided when a POC breaks down.