The 65-year-old, identified by the Bild newspaper as Werner M., collapsed while walking his dog right next to Düsseldorf's Augusta hospital in the early hours of Tuesday morning.
He was suffering from pulmonary oedema – fluid on the lungs.
He fell to the floor, and a passer-by ran the short distance to hospital where he found a porter who allegedly told him that doctors could not leave the hospital.
They instead sent a fire engine with medical equipment, which took seven minutes to arrive then had to drive him to the hospital. By that time it was too late, and despite all efforts by hospital staff, the man died.
“It would have been better to have informed a doctor,” the hospital said in a statement about the incident.
A hospital spokesman said that it would have been possible for a doctor to to leave the hospital if they were not needed elsewhere.
On Thursday, the state prosecutor ordered an autopsy of the man's corpse, Bild newspaper reported.