Bleeding, technically known as hemorrhaging or haemorrhaging (see American and British spelling differences), is the loss of blood or blood escape from the circulatory system. Bleeding can occur internally, where blood leaks from blood vessels inside the body, or externally, either through a natural opening such as the vagina, mouth, nose, ear or anus, or through a break in the skin. Desanguination is a massive blood loss, and the complete loss of blood is referred to as exsanguination. Typically, a healthy person can endure a loss of 10–15% of the total blood volume without serious medical difficulties, and blood donation typically takes 8–10% of the donor's blood volume.

Hemorrhaging is broken down into four classes by the American College of Surgeons' Advanced Trauma Life Support (ATLS).

This system is basically the same as used in the staging of hypovolemic shock.

Individuals in excellent physical and cardiovascular shape may have more effective compensatory mechanisms before experiencing cardiovascular collapse. These patients may look deceptively stable, with minimal derangements in vital signs, while having poor peripheral perfusion. Elderly patients or those with chronic medical conditions may have less tolerance to blood loss, less ability to compensate, and may take medications such as betablockers that can potentially blunt the cardiovascular response. Care must be taken in the assessment of these patients.

Leona Louise Lewis (born 3 April 1985) is a British singer and songwriter. Lewis came to prominence in 2006 when she won the third series of the British television series The X Factor.

Lewis has released two albums to date, Spirit and Echo, in 2007 and 2009 respectively. A multi-platinum selling artist and three-time Grammy Award nominee, her most successful single, "Bleeding Love", reached number one in over thirty countries around the world, and was the best-selling single worldwide in 2008. Other notable singles include "Better in Time", "Happy" and "I Got You". She was proclaimed 'Top New Artist' by Billboard magazine in 2008.

Lewis's debut tour, The Labyrinth, took place in 2010, and her third album, Glassheart, is scheduled for release in 2012. It was preceded by "Collide", a single from the album, which became her seventh top-five hit in the United Kingdom. Lewis's net worth was estimated at £12 million in April 2012.

Jesse McCartney (born April 9, 1987) is an American singer-songwriter, actor, and voice actor. McCartney achieved fame in the late 1990s on the daytime drama All My Children as JR Chandler. He later joined boy band Dream Street, and eventually branched out into a solo musical career. Additionally, McCartney has appeared on shows such as Summerland and Greek. McCartney also is known for lending his voice as Theodore in Alvin and the Chipmunks and its sequels, as well as voicing the characters Roxas and Ventus in the video games series Kingdom Hearts developed by Square Enix.

McCartney was born on April 9th in Westchester, New York, the son of Ginger (née Sarber) and Scott McCartney. He began performing in local community musicals at the age of seven, before joining the national tour of The King and I at age ten along with Phil of the Future star Ricky Ullman. Here he played the character of Louis. In 1998, he sang with the group Sugar Beats and can be heard on their 1998, 1999, and 2000 CD releases.