Here are some general things you can do while you wait for the vet:
* Keep your dog calm and still. Don't try to move them if there's a suspected broken bone or spinal injury.
* Control any bleeding. Apply pressure to the wound with a clean cloth.
* Keep your dog warm. If possible, wrap them in a blanket.
* Keep them hydrated. If your dog is able to drink, offer them water.
* Don't give them any medication. Only give medication prescribed by your veterinarian.
It's important to remember that even minor injuries can be serious in a Great Dane due to their size and breed characteristics. Don't hesitate to seek immediate veterinary attention.