A home health nurse who repeatedly stole painkillers from a sick and elderly patient was sentenced Tuesday to 18 months in prison, an unusually long term that prosecutors sought because of the victim’s vulnerability.

La Vang, 27, of Newport, had pleaded guilty in federal court to obtaining controlled substances by fraud, a felony, after he was accused of stealing potent pain medications from the home of an 85-year-old woman recovering from multiple surgeries. Vang covered up the thefts for five months by covertly replacing the stolen pills with over-the-counter medications, which caused the woman to suffer extreme pain and become lethargic and incoherent, according to prosecutors and relatives of the victim.

Suspicions arose when multiple blood and urine samples failed to show evidence of opiates in the woman’s system.

Vang, a former nurse with Lifesprk, a home health company in St. Louis Park, was arrested on Aug. 2, 2018, after police in Columbia Heights conducted a sting operation in which they observed the woman’s medication before and after his visit to the home. The surveillance revealed that Vang was putting similar-looking Tylenol tablets and allergy medication into the woman’s medication dispenser and bottles. Police officers discovered several empty bottles of narcotics with the woman’s name when they stopped Vang as he left her home, according to court documents.

Vang’s employment with Lifesprk ended on May 1, 2018, though he continued to visit the patient at her home under the guise of still being a nurse at the company, according to court documents.

Federal prosecutors sought and obtained an upward departure from the sentencing guidelines of six to 12 months, citing the woman’s prolonged suffering as well as Vang’s unusual position of trust and power over the victim.

“[Vang] betrayed the central tenet of his profession and harmed the very person who trusted him to provide care,” wrote U.S. Attorney Erica MacDonald in a Nov. 19 court memorandum urging for a tougher sentence. “[Vang] acted with callous disregard to his own patient and let her suffer needlessly for months.”

The elderly victim, LaVonne Borsheim, attended the sentencing hearing Tuesday in her wheelchair, along with eight relatives and several elder rights advocates. One of her daughters read a statement from Borsheim, who was still too weakened and traumatized from the crimes to speak on her own. “I could have lost my life due to La Vang giving me medications that I wasn’t supposed to have, yet he took for himself,” read Kari Huguelet-Shaw, a daughter who lives in San Diego. “He took my trust away and confidence in the health care industry forever.”