Do you know when not to call for an ambulance for a medical problem? It seems one in three people don't, according to a new survey.

The online survey of 150 adults in the U.K. found that most people know they should call an ambulance when someone appears to be having a heart attack or other life-threatening medical emergency.

But many don't understand when an ambulance is not needed for less urgent situations, like going into the early stages of labour.

The survey presented 12 common medical scenarios, five that require an ambulance to be called, and five that would not.

Almost all the participants correctly identified at least three of the five scenarios in which a 911 call is needed (In the UK., the emergency call number is actually 999). They were:

  • Middle-aged man with pains in his chest (possible heart attack)
  • Possible acetaminophen overdose
  • Traffic accident victim
  • Older person slurring his words after not having had any alcohol (possible stroke)
  • 4-year-old with high temperature and stiff neck (possible meningitis)

But one in four did not recognize the need to call for an ambulance in the case of the possible stroke. That finding was "concerning," the authors said, and made them wonder whether stroke awareness campaigns aren't working.

When it came to situations when a 911 call is not needed, the respondents didn't do so well. Most only could pick out two out of the seven scenarios in which there would be no need for an ambulance. Between 5 and 48 per cent would have dialled 911 for these situations:

  • Woman going into the early stages of labour
  • Man with chronic back pain who has run out of painkillers
  • Drunk man being sick (but not unconscious)
  • 3-year-old with a toy stuck up his nose
  • An episode of blood in the urine
  • Toddler with a bruise on his head
  • Knife cut on the palm of the hand that is not bleeding heavily

The researchers note that while some of these scenarios require medical help ranging from first aid to an emergency department visit, not one requires an ambulance to come to their aid.

"It is highly likely that there is confusion between the need for medical treatment and the need for an ambulance," the authors write.

Interestingly, two-thirds of the survey participants had undertaken some first-aid training. The authors conclude that more widespread education on when to call for emergency care would be useful and would help cut costs from unnecessary ambulance calls. It would also help ensure that those who do need emergency assistance can get it promptly.

The study results appear in the Emergency Medicine Journal.