Do not resuscitate
Some people choose to avoid aggressive measures at the end of life. A do not resuscitate order (DNR) in the form of an advance health care directive makes it clear that in the event of cardiac arrest, the person does not wish to receive cardiopulmonary resuscitation. Other directives may be made to stipulate the desire for intubation in the event of respiratory failure or, if comfort measures are all that are desired, by stipulating that healthcare providers should "allow natural death". Chain of survival
Several organizations promote the idea of a chain of survival. The chain consists of the following "links":

Early recognition If possible, recognition of illness before the person develops a cardiac arrest will allow the rescuer to prevent its occurrence. Early recognition that a cardiac arrest has occurred is key to survival for every minute a patient stays in cardiac arrest, their chances of survival drop by roughly 10%. Early CPR improves the flow of blood and of oxygen to vital organs, an essential component of treating a cardiac arrest. In particular, by keeping the brain supplied with oxygenated blood, chances of neurological damage are decreased. Early defibrillation is effective for the management of ventricular fibrillation and pulseless ventricular tachycardia
Early advanced care
Early post-resuscitation care which may include percutaneous coronary interventionIf one or more links in the chain are missing or delayed, then the chances of survival drop significantly.
Those affected tend to hold the shoulder rotated inwards to alleviate pain, and have difficulty lying on the affected shoulder. Some people experience heat and redness at the affected shoulder, as well as a limited range of motion. Cause
Calcific tendinitis is caused by deposits of calcium phosphate crystals in the tendons of the shoulder. These deposits are most frequently found in the supraspinatus tendon (63% of the time), and less frequently in the infraspinatus tendon (7%), subacromial bursa (7%), subscapularis tendon (3%), or in both the supraspinatus and subscapularis tendons at the same time (20%).The development of calcific tendinitis is often divided into three stages. First, in the "precalcific stage", something causes tendon cells to transform into other cells that can act as sites for calcium deposition. This is followed by the two-part "calcific stage"; first calcium is deposited (the formative phase), then the body begins to break down the calcium deposit (the resporptive phase). Finally, in the "postcalcific stage" the calcium deposits are replaced with new tissue and the tendon completely heals.The cause of the calcium deposits remains unclear, although several theories have been put forward. Some theories involve the differentiation of tendon cells into other cells, namely cartilages or bone cells. Others associate the condition with cell death due to aging, wear, or lack of oxygen in the tissue; however, the disease is uncommon in the very old, not associated with exercise, and tends to resolve completely even if untreated. Diagnosis
Calcific tendinitis is typically diagnosed by physical examination and X-ray imaging.