John Odom was just a month from retirement when he came to Boston to watch his daughter Nicole run the marathon. Now he is among the most critically injured bombing victims, scheduled to undergo his seventh surgery Tuesday, according to his wife, Karen.

Shrapnel from the first explosion severed an artery in Odom’s leg, and he bled extensively before making it to the hospital, where he went into cardiac arrest. “He’s the sickest of anyone, of all the patients, is what they told us,” his wife said.

Odom, a mechanical contracting businessman from Redondo Beach, Calif., was watching the race with family, including his daughter’s husband and a 6-year-old grandson. The force of the first blast threw everyone to the ground, recalled Karen Odom, who was standing in front of her husband at the finish line. “John started saying, ‘My leg, my leg. Oh, Karen, my leg,’ ” she recalled.

Karen wasn’t injured by either bomb — “I didn’t have a scratch on me” — and she rushed to help her husband. Their son-in-law, Matt Reis, who plays professional soccer for the New England Revolution, tied a tourniquet around Odom’s leg, and a fireman with a backboard helped carry him to an ambulance. “It’s a miracle,” Karen said. “We hope the miracle continues.”

The family has kept vigil at the hospital. Odom is on a ventilator, and he is battling infection. “The last two days have been really rough,” his wife said.

John Odom, 65, of Torrance, Calif. (Courtesy of Karen Odom)

Karen paid only passing attention to last week’s manhunt. “I guess I’m happy they caught the one guy alive, because I’d love to know why he targeted families,” she said.

Suzy Khimm