"I just couldn't believe what I was seeing, it becomes very surreal," Melissa says in an upcoming interview with the Today show

By Jacqueline Andriakos
May 01, 2015 12:00 PM

Melissa Rivers shares her personal memories of her mother, Joan, and the lessons she taught her about laughter and love. Subscribe now for instant access to this exclusive interview, only in PEOPLE.

Melissa Rivers says that her mother Joan Rivers‘ death could have been avoided.

In an upcoming interview airing Monday on the Today show, the television host and daughter of the late comedian opened up about seeing Joan in her final hours in the hospital.

“I just couldn’t believe what I was seeing … it becomes very surreal,” the author, 47, told host Matt Lauer, also describing how she received emails that Rivers was already in a medically induced coma while she was still on the plane.

“In my opinion, it was 100 percent preventable,” Rivers told the host of her mother’s death. “How about paying attention to the vital signs? How about having a properly equipped crash cart?”

But Rivers believes her mother knew she was there beside her hospital bed, telling PEOPLE, “I was grateful to have had those few days to be able to let go a little bit. I tried to make the transition as peaceful and beautiful as she would want it to be.”

Rivers has since filed a malpractice lawsuit against the clinic where the comedian underwent the surgery before her death.

Joan stopped breathing during a surgical procedure on her vocal cords at the New York City clinic in August and died a week later at the age of 81.

According to the complaint obtained by PEOPLE in January, doctors performed procedures beyond what Joan had consented to while she was sedated, and medical personnel failed to realize she was losing oxygen until it was too late. Other claims said that doctors continued to operate even as Joan’s blood pressure and heart rate dropped.

“Not only did my mother deserve better, every patient deserves better. It is my goal to make sure that this kind of horrific medical treatment never happens to anyone again,” Rivers said in a statement at the time.

RELATED VIDEO: Melissa Rivers Reveals When She Misses Joan Most

Advertisement