Also known as: Kidney failure
Sarah is dying from kidney failure after a failed transplant in Seattle. She needs an emergency kidney transplant from her sister Emily within 72 hours or she will go into full renal failure and die. The episode centers on the surgical team's efforts to save her life.
Also known as: AIDS
Emily, the kidney donor, is discovered to be HIV positive during pre-surgery testing. This creates a major ethical and legal dilemma as transplanting an HIV-infected organ is illegal, but Sarah will die without it. The doctors must weigh the risks of HIV transmission against certain death.
Also known as: Blood around the heart
During the kidney transplant surgery, Sarah develops pericardial tamponade with dropping blood pressure. Sam performs an emergency pericardial window to drain the fluid, revealing his hidden surgical background.
Also known as: Immune deficiency disorder
Ryan is a 16-year-old who has lived in isolation for nearly two years while rebuilding his immune system after being born without one. Cooper tries to boost his immune system so he can attend homecoming, but Ryan's mother develops flu symptoms, exposing him to life-threatening infection.
Also known as: Blood infection
Ryan collapses at the homecoming dance with fever, tachycardia, dropping blood pressure, and low oxygen saturation. His compromised immune system makes him vulnerable to rapidly progressing sepsis from exposure to his mother's flu.