The nation’s leading organization for overseeing hospital patients’ safety is investigating Parkland Memorial Hospital, this time after the deaths of two psychiatric patients,The Dallas Morning News has learned.

The nonprofit Joint Commission acknowledged that it is investigating the death of a patient who was placed in solitary confinement in the psychiatric emergency department in February and another who fled Parkland in October and was struck by a car.

The commission recently closed a third case involving a mental health patient who died of a heart attack in February 2010 shortly after being discharged from the psychiatric clinic without receiving a medical examination.

“”We worked with the organization to make sure they took steps to ensure something like this is prevented from recurring,”” said Elizabeth Zhani, media relations manager for the commission, referring to the closed case. She did not disclose what actions the hospital took.

Parkland officials declined to comment on the inquiries, citing concerns about patient confidentiality.

The inquiry into the Dallas County public hospital’s psychiatric care is the latest investigation into patient safety issues by the agency to come to light in recent months.

The Chicago-based commission operates as a voluntary accreditation agency for more than 4,000 hospitals nationwide. It doesn’t have the authority to close or fine hospitals. But it can strip them of accreditation, without which they cannot receive government funding.

Under its agreement with hospitals, it keeps most details of inquiries and findings confidential in an agreement with medical facilities.

In December, The News reported that the commission was examining the botched surgery of a former Parkland employee, Jessie Mae Ned, whose knee operation by a doctor in training led to an amputation. Zhani said that case was closed after the commission worked with Parkland “”to make improvements.””

Before the commission’s actions, the last known investigation into Parkland’s handling of psychiatric patients came in 2006, when the U.S. Centers for Medicare & Medicaid Services found that Parkland didn’t safeguard a depressed patient who was raped in her hospital room. The hospital says it later remodeled the ward to improve observation of patients.

Medical safety experts called the string of recent deaths unusual.

“”To have three deaths in that time frame, you want to take a close look and make sure you’re taking really good measures to protect patients,”” said Dr. Al Herzog, a Connecticutpsychiatrist and former chair of the American Psychiatric Association’s patient safety committee. He said the deaths raise questions about whether Parkland has effective monitoring and secure premises.

Zhani said the commission is assisting Parkland with performing a root cause analysis of the Oct. 10 death of the patient killed in traffic.

The News identified the most recent psychiatric patient who died — 49-year-old George Cornell, who had been placed in solitary confinement — through the Dallas County medical examiner’s office. His cause of death was listed as a dysrhythmia, an abnormal heart rhythm, due to an enlarged heart. He suffered from paranoid schizophrenia.

The commission said in a response to The News’ questions about the Feb. 10 incident that “”seclusion in the psychiatric ED 1/8emergency department3/8 resulted in death.””

Placing psychiatric patients in seclusion, or solitary confinement, is considered a last resort by many hospitals because it can lead to emotional and physical trauma. Parkland’s own policy says its leaders are committed to “”prevent, reduce and strive to eliminate restraint and seclusion,”” according to its 2008 nurse procedure manual.

Cornell’s mother, Jane Pena, said he had a history of heart problems. She wonders if he received any medical care at Parkland. And she said she wasn’t told he was placed in seclusion. Parkland policy calls for informing “”each individual and/or family of the organization’s”” approach to seclusion.

“”I’m glad they’re looking into it,”” Cornell’s mother said of the commission review.

Her son left their Oak Cliff home in the middle of the night without her knowledge to seek help for chest pains at a nearby fire station, a fire department official later informed her. He also was apparently delusional, she said, talking about fears of burglars breaking into their home.

The fire personnel contacted police officers, who transported him to Parkland around 1:30 a.m., she was told. She received a call from a Parkland psychiatric worker around 4:30 a.m., saying her son had died after resisting an injection to calm him.

“”They told me he was agitated, and they gave him a shot to calm him down and it didn’t do anything,”” Pena recalls. “”They went to get a second one and he resisted. While he resisted, he was pulling up floor tile. He suddenly went limp and they checked his pulse. He had no pulse.””

The medical examiner characterized Cornell’s death as “”natural”” on his death certificate.

Pena she said she never saw her son act aggressively.

Dr. Eric Thomas, director of the UT Houston-Memorial Hermann Center for Healthcare Quality and Safety, said a key question in determining whether proper care was provided for psychiatric patients with multiple medical conditions is whether enough expertise is on hand to oversee the care.

“”Those patients obviously require co-management with a cardiologist or another specialist or a general internist,”” Thomas said.

Cornell spent the last few years of his life, his mother said, trying to cope with his health problems by immersing himself in woodwork, building crystal radios and practicing Buddhist chants in the quiet of their backyard.

“”He was a gentle soul,”” Pena said. “”I’ve thought, I can’t bring him back. But if other people are being harmed because of some wrongheaded policy, it would be a public service to get to the bottom of it.””