A Florida surgeon who is facing criminal charges after allegedly removing a patient’s liver instead of his spleen has said he is “forever traumatized” by that person’s death.

In a deposition from November that was recently obtained by NBC, 44-year-old Thomas Shaknovsky described the death of 70-year-old William Bryan as an “incredibly unfortunate event that I regret deeply”.

Bryan died after the botched surgery; and in April, a grand jury in Tallahassee indicted Shaknovsky on a charge of manslaughter.

“I’m forever traumatized by it and hurt by it,” Shaknovsky added, also saying that wrong-site surgeries can happen “during difficult circumstances”.

The deposition provided Shaknovksy’s first detailed account of the operation that killed Bryan and eventually garnered national news headlines.

According to Shaknovksy’s deposition, after removing Bryan’s liver, the surgeon instructed a nurse to label the organ as a “spleen” – and he also identified it as a spleen in Bryan’s postoperative notes. Shaknovsky later said he had been “mentally compromised” at the time of Bryan’s death, explaining that he was “devastated, demoralized, crying over his passing, felt that I failed him”.

A lawsuit filed by Bryan’s widow, Beverly Bryan, accuses Shaknovsky of medical malpractice. The suit alleges that he “wrongfully omitted any reference to Mr Bryan’s liver being removed in order to ‘cover up’ his gross negligence/recklessness and to hopefully avoid the embarrassment due to such derelict care”, as NBC reported.

In April, the Walton county sheriff’s office said in a statement that Shaknovsky’s actions inflicted on Bryan “catastrophic blood loss and the patient’s death on the operating table”.

Shaknovsky’s deposition testimony described the chaos in the operating room after Bryan began bleeding extensively, causing his heart to stop. Medical staff performed chest compressions, and Shaknovsky attempted to find where the bleeding was coming from.

“I couldn’t tell the difference because I was so upset,” he said, referring to the organ he mistakenly identified.

“It was like a overflown sink that’s clogged up, and I am looking for a fork at the bottom, trying to feel and find the bleed, and I was not able to do so,” Shaknovsky said. He added: “After 20 minutes of struggling – desperately trying – to save his life, that’s when the wrong-site event took place.

“It’s a devastating thing, which I will have to live with the rest of my life,” Shaknovsky said in the eight-hour deposition reviewed by NBC. “I think about it every single day.”

After the medical team was unable to resuscitate Bryan, Shaknovsky said he went to the hospital’s medical library. “I went there to cry because I was devastated,” he said. “I didn’t want the staff to see me like that.”

Despite a spleen typically being significantly smaller than a liver, Shaknovsky said he believed Bryan’s spleen was “double the size of what is normal” because of a mass on it. Beverly Bryan’s lawsuit, however, states that a medical examiner told her that her husband’s spleen was anatomically “nearly normal”, according to NBC.

Shaknovsky would face up to 15 years in prison and a fine of up to $10,000 if eventually convicted as charged.