A trial taking place at University Hospitals Birmingham NHS Foundation Trust (UHB) could lead to changes in how people are instructed to deliver CPR by ambulance telephone operators.

The DIRECT study recruited 330 people, and measured how well they performed CPR on a manikin based on different sets of instructions.

CPR, which involves pressing down on someone’s chest if they have a cardiac arrest, helps to keep blood circulating around the body. 999 operators instruct people how to do this over the phone if they have not received training or are unsure how to do it.

The trial, which mainly took place at Heartlands and Solihull hospitals, was open to anyone who had not delivered CPR in the last two years.

The trial was led by Keith Couper, Critical Care Outreach Practitioner, who said: “The trial compared three sets of instructions. The results suggest that the best instruction to give was ‘press hard and fast’, as this made people more likely to press down quickly and firmly enough.

“We found that the other instructions to press approximately, or press at least, 5cm or 2 inches were less likely to lead to effective CPR.

“I’d like to thank everyone who took part, as well as my colleagues Sam Trethewey, Hrushi Vyas, Michelle Hall, Prof Gavin Perkins, Teresa Melody, the Critical Care research team, and Resuscitation Council (UK) who funded the research.”

The results of DIRECT will soon be published in a medical journal, and will help inform the wording used by 999 ambulance operators in the future.