One-third of patients arriving at Perth emergency departments by ambulance are waiting more than an agreed maximum time of 20 minutes to be transferred to the care of hospital staff.
A new "ticking clock" indicator introduced into public hospitals showed in the past week less than 70 per cent of ambulance patients were "off stretcher" within 20 minutes. Some hospitals, including Swan District, were struggling to get half their patients into hospital in that time.
The off-stretcher target has been used in most States for several years to measure the time it takes for patients to be taken into busy emergency departments.
Unlike ramping figures, which show delay times for ambulances, the off-stretcher measurement calculates the time it takes for patients to be transferred from the care of paramedics into the hands of emergency department staff.
The WA Health Department said it had been introduced in co-operation with St John Ambulance to provide a more complete picture of hospital performance and would be used alongside ambulance ramping data to provide comparisons against previous years.
A spokesman said it had been agreed with St John Ambulance that 20 minutes was a reasonable time to hand over a patient.
"Off-stretcher time focuses on the delay patients may experience before their care is transferred to the hospital's emergency department, whereas ambulance ramping highlights the delay before the ambulance vehicle returns to active service," he said.
"Off stretcher is a more valid way of measuring emergency department access to patients arriving by ambulance, as ramping takes into account the extra time it takes to clean and restock the ambulance.
"The aim is for ambulance ramp time to decrease and the percentage of cases transferred into emergency care within 20 minutes to increase. This new measure brings WA in line with other States . . . which all report an equivalent measure to off-stretcher time."
Australian Medical Association WA emergency medicine spokesman Dave Mountain said though it was important to have ambulance ramping figures, the new system was more transparent.
"Off-stretcher times give a bit more nuance to the numbers and allows us to see if ambulance off-load or the hospital is the issue," Dr Mountain said.