I have heard conflicting information on back blows for an adult. The first action to take is the Heimlich maneuver. This should be done in adults instead of back blows since back blows may lodge the foreign body further down the windpipe. Back blows are the first thing to do only in infants who are conscious. In doing the back blows the infant should be in a face down position, ie the head is lower than the body.
Vomit is obviously unpleasant.
If someone collapses from an asthma attack, it is because he or she is not getting enough oxygen. This is because all the lung's small airways have narrowed and are not allowing enough air to reach the air sacs. Mouth to mouth respiration may help a little. Usually CPR in infants and children is performed for respiratory arrest such as severe asthma. Ventricular fibrillation is rare in children but very common in older adults.