A Mount Sinai Hospital technician — responsible for running complicated equipment during open-heart surgeries — watched porn on his smartphone as patients lay with their lives in the balance just inches away, according to a bombshell lawsuit by former cardiovascular tech Sandra Morris.

“I once saw him watching a of a woman riding a man,” Morris, 37, said of Ahmed Cercioglu, whom she names in her Manhattan Supreme Court lawsuit.

“Another time, I saw him watching a guy [having sex with] a girl and the girl [giving the man oral sex],” Morris claimed of Cercioglu, her former boss.

Both she and Cercioglu toiled as cardiovascular perfusionists — techs responsible for setting up and running the sophisticated heart-and-lung machine that keeps patients alive while surgeons repair their organs.

She said Cercioglu’s porn habit was so “commonplace [in the operating room] that other perfusionists routinely joked about his behavior,” according to the lawsuit she filed last week.

Morris is suing her former supervisor, the hospital and another boss, Ricardo Lazala, for allegedly creating a hostile work environment.

She and her lawyer provided The Post a copy of a departmental memo banning the use of cellphones in the operating room last year, on which someone in his office crossed out the word “cellphone” and replaced it with “porn.”

In her suit, filed July 31, Morris also alleged that Cercioglu, a Muslim, regularly degraded her for being female and an observant Jew. He went so far as to blast her publicly as a “dumb Jew bitch” in front of co-workers, the lawsuit claims.

Morris — who claims she was booted for being out of work for months on disability after a fall she suffered on the job — also alleges in the suit that Cercioglu and his supervisor, Lazala, passed her over for assignments because she was female.

“Ms. Morris was told several times [by Cercioglu and Lazala] . . . that she cannot work on [those] cases because she doesn’t have a ‘d–k,’ ” her suit claims.

Hospital officials, citing the pending litigation, declined to comment and said none of the employees involved in the case could respond either.