A defrosted corpse, a swab left in a surgery patient and an anaesthetist electrocuted by a defibrillator were reported as serious incidents tripled at south west Hertfordshire hospitals last year.
West Hertfordshire Hospitals Trust, which runs Watford General and St Albans City hospitals, saw the number of serious incidents reported last year surge to 148 compared to 54 the year before.
Health bosses attributed the dramatic increase to the fact staff were now being encouraged to report failings to their superiors.
Papers released by the trust revealed the most grievous failing at its three hospitals between April last year and this April.
In one case in 2013 a freezer in a mortuary failed leaving a patient’s body to thaw out. The trust said when it was discovered the corpse was moved to another freezer and an alarm system has since been installed to warn staff if any of the units fail.
In another incident an anaesthetist received an electric shock while holding an oxygen mask on a patients face when another doctor used a defibrillator in a resuscitation attempt. The trust said it had since provided addition training around using defibrillators.
The health trust also said that it had also created a safer surgery steering group after a swab was left in a patient.
Dr Mike Van Der Watt, Medical Director, said: "Maintaining the safety of patients is our number one priority.
"As a large organisation with three hospitals treating more than 600,000 patients a year, it is inevitable that incidents will occur.
"It is important that staff feel able to report incidents and we need to be careful to avoid apportioning blame in a way which limits or stops this. As such, we actively encourage our staff to be open and honest, and to report incidents so that we can learn from them.
"Hospitals that fail to report incidents can be seen as having a ‘poor’ safety culture and, as such, could be risking the safety of their patients by not being open and honest. The reporting rate at our Trust compares favourably with other hospitals of a similar size.
"What is important is that we act quickly when something does go wrong, and that we learn from every incident and share this learning across our hospitals, in order to reduce the likelihood of it happening again.
"We are committed to being open about incidents and they are reported on a monthly basis at our Trust Board. The serious incident annual report is a review of the entire year and allows us to bring together overall themes of incidents and to give an overview of the actions taken and lessons learned.
"We had expected to see a marked increase in the number of incidents reported in 2013/14, in particular as a result of a proactive drive across our hospitals to encourage staff to report incidents. This included providing new training to help staff identify incidents. We will continue to do this as we move forward."
Other serious incidents recorded by the trust last year included one episode where a patient had the wrong part of their body operated on, two unexpected deaths, a still birth, 34 incidents involving serious ulcers and 16 involving communicable diseases and infections.
There were also ten serious allegations against trust staff recorded, 21 serious incidents relating to care and treatment and ten relating to medication.