1. Head Tilt-Chin Lift (if there's no suspected neck injury):
- This is the preferred method if the casualty is unconscious and has no signs of neck injury.
- Gently tilt the head back by placing one hand on the forehead and the other under the chin.
- Lift the chin forward to clear the airway while keeping the neck in line.
2. Modified Jaw Thrust (if there's suspected neck injury):
- This technique is used when there's a possibility of neck injury.
- Place your hands on both sides of the casualty's head, near the jaw angles.
- Without tilting the head, gently push the jaw forward and up, lifting the mandible.
3. Nasopharyngeal Airway (NPA):
- If the casualty's airway remains obstructed, and the head and neck must be immobilized, an NPA can be used.
- Lubricate an NPA with water-based gel and carefully insert it through the nostril into the nasopharynx.
- Advance it until resistance is met and secure it in place.
4. Oropharyngeal Airway (OPA):
- An OPA can be used if insertion via the nasal route is unsuccessful or contraindicated.
- Lubricate the OPA and gently insert it into the mouth, over the tongue and into the oropharynx.
- Advance until resistance is encountered, and ensure its placement without gagging.
5. Bag-Valve Mask (BVM):
- If the airway remains obstructed and it's not feasible to insert an airway device, use a bag-valve mask (BVM) with minimal neck movement.
- Place the mask on the casualty's face, minimizing head and neck movement, and provide positive pressure ventilation.
Remember that these techniques should be applied by trained individuals while maintaining cervical spine immobilization if a neck injury is suspected. If advanced medical help is expected soon, it may be best to avoid manipulation and allow for spontaneous breathing until professional assistance arrives.