This was on HN some time ago - apparently there is some sort of research that states that patting/whacking on the back was in fact as affective as Heimlich manoeuvre.
Mayo Clinic: http://www.mayoclinic.org/first-aid/first-aid-choking/basics...
European Resuscitation Council: http://ercguidelines.elsevierresource.com/european-resuscita...
Australia (and New Zealand) Resuscitation Councils: http://www.nzrc.org.nz/training/ECI/anzcor-guidelines-2016-u...
In the case of Australia/New Zealand the recommendation is to do 5 Back Blows then 5 Chest Thrusts. My understanding is that it's believed to be similarly effective but has less risk of causing internal injuries.
A secretary at my workplace had a piece of pork rib stuck but there was still air getting by. An ambulance was called and the medic walked over and slapped her back to remove the food.