Variations on techniques to evaluate and maintain the ABCs depend on the skill level of the first aider. Once the ABCs are secured, first aiders can begin additional treatments or examination, as required if they possess the proper training (such as measuring pupil dilation). Some organizations teach the same order of priority using the "3Bs": "Breathing", "Bleeding", and "Bones" (or "4Bs": "Breathing", "Bleeding", "Burns", and "Bones"). While the ABCs and 3Bs are taught to be performed sequentially, certain conditions may require the consideration of two steps simultaneously. This includes the provision of both artificial respiration and chest compressions to someone who is not breathing and has no pulse, and the consideration of cervical spine injuries when ensuring an open airway. The patient must have an open airway—that is, an unobstructed passage that allows air to travel from the open mouth or uncongested nose, down through the pharynx and into the lungs. Conscious people maintain their own airway automatically, but those who are unconscious (with a GCS of less than 8) may be unable to do so, as the part of the brain that manages spontaneous breathing may not be functioning. Whether conscious or not, the patient may be placed in the recovery position, laying on their side. In addition to relaxing the patient, this can have the effect of clearing the tongue from the pharynx. It also avoids a common cause of death in unconscious patients, which is choking on regurgitated stomach contents. The airway can also become blocked by a foreign object. To dislodge the object and prevent choking, the first aider may use techniques such as ‘back slaps’ and ‘abdominal thrusts’. Once the airway has been opened, the first aider would reassess the patient's breathing. If there is no breathing, or the patient is not breathing normally (e.g. agonal breathing), the first aider would initiate CPR, which attempts to restart the patient's breathing by forcing air into the lungs. They may also manually massage the heart to promote blood flow around the body. If the choking person is an infant, the procedure is to deliver five strong blows on the infant's upper back after placing the infant's face in the aider's forearm. If the infant is able to cough or cry, no breathing assistance should be given. Coughing and crying indicate the airway is open and the foreign object will likely to come out from the force the coughing or crying produces.