Kyle Flack, who had cerebral palsy, died at Basildon University Hospital in October 2006 after his head became trapped between the bottom rail surrounding his bed and the edge of the bed itself.
Basildon and Thurrock University Hospitals NHS Foundation Trust, which had pleaded guilty at an earlier hearing in February, was also ordered to pay £40,000 in costs after it was prosecuted by the Health and Safety Executive.
During this earlier hearing, Basildon Crown Court heard there had been a similar incident during an earlier stay at the hospital after he had forced his head part way through the rails.
Kyle, 20, who was described as having the body of a 12-year-old, was also blind, deaf and quadriplegic, and died from asphyxiation.
Investigations by the HSE found the trust had no systems in place on each ward for assessing the risk to patients from bed rails.
People with cerebral palsy are known to be particularly at risk of entrapment and the issue was highlighted in Department of Health guidelines published in 2001.
Kyle’s mother, Gill Flack, said: “When you put your child into hospital, you expect him to be cared for and to pick him up once his treatment is over.
“There will never be closure for us as Kyle can never be replaced but through the support of HSE, this result has helped us to feel that justice has finally been done.”
HSE inspector Sue Matthews said: “This was an entirely preventable incident that resulted in the death of a vulnerable and much-loved young man.
“Simple measures should have been taken to prevent this from happening.”
The trust’s director of nursing, Maggie Rogers, said it “fully accepts its failings” and the court’s sentence, but insisted lessons had been learned.
She added: “In the years since Kyle’s tragic death, we have completely reviewed the care provided to patients with learning disabilities and have put in place many improvements. This includes training for all staff, many changes to protocols and procedures and over £1million of investment to re-equip the hospital with new beds and bed-related equipment.
A Care Quality Commission spokesperson said: “We have been looking extremely closely at the quality of care for people with learning disabilities at the trust to check that the lessons have been learned.
“On our visits, we found some progress to improve the care of people with a learning disability, but more is needed.”