[magneticnorth]

The idea of the heimlich is to put sudden force on the diaphragm and force air upward. You can do that alone by pushing your upper abdomen against a chair back, counter, railing, whatever. Not something I've ever tried, but good to know about in case.

[inciampati]

And if you're alone it's worth running with a chair into the street to do it as visibly as possible.

[hhmc]

Sure theoretically. Outcomes are dramatically better if someone else is around