Caritas Medical Centre said on Wednesday it had launched an internal investigation into the death of a patient who did not receive oxygen during a transfer between wards on Tuesday.

The patient, 79, who had undergone ulcer and hernia surgery, was awaiting an eye operation when his condition worsened on Tuesday morning and he developed oxygen desaturation. Doctors at the hospital in Sham Shui Po believe he had suffered intestinal obstruction.

He received oxygen, but doctors decided he should be transferred from the eye ward to the intensive care unit. On the way between the wards, his condition deteriorated again. On arrival at the ICU about five minutes later staff discovered that the oxygen cylinder used during the transfer had not been opened.

The man received a proper oxygen supply as well as intubation and cardiopulmonary resuscitation in the ICU, but his condition continued to deteriorate and he died about an hour and a half later.

The hospital said it had reported the incident to the Hospital Authority and had set up a root cause analysis panel to look into the case and review how patient transfers are handled. It says immediate measures have been put in place to check medical equipment used during transfers.

"The hospital is deeply saddened by the passing away of the patient," it said in a statement.

"The hospital has met with the patient's relatives to explain the incident, and extended sincere apologies and condolences. The hospital will continue to keep in contact with the family to offer all possible assistance."

The case has also been passed to the coroner.