​Imagine this. A soccer player severely fractures his leg during a game and an ambulance is called to the scene. Upon arrival, the paramedics run across the field to the injured player, carrying along with them medical supplies, which includes a bulky cylinder tank of Entonox (nitrous oxide gas) used for pain relief.

Pain is one of the most common symptoms in casualties that paramedics attend to at the scene of an emergency. Control of pain is important not only for humanitarian reasons but also because it may prevent the condition from deteriorating and allows better pre-hospital assessment. Paramedics must therefore be equipped to deliver pain relief early.

In a bid to improve pre-hospital emergency care, Singapore General Hospital (SGH) and Singapore Civil Defence Force (SCDF) are looking at ways to enhance the pain relief delivered to patients. The evaluation, which was launched in February 2014, involves four hundred eligible patients who sustained limb injuries over a one-year period to determine the effectiveness and suitability of two medications – Penthrox (methoxyflurane) and Tramadol, for early pain relief. These medications are delivered via a palm-sized inhaler or an injection, making it much more portable as compared to the Entonox tank. A fleet of SCDF ambulances are equipped with the medication. Since September 2013, doctors from SGH’s Department of Emergency Medicine have been training SCDF paramedics on the use of both medications.

“We have worked with the Singapore Civil Defence Force on many occasions to improve patient care before they arrive at the Emergency Department, as early delivery of care often equates to favourable patient outcomes. If Penthrox or Tramadol proves its efficacy for use in the pre-hospital setting, paramedics will have a much better ability to administer early pain relief than what we have currently,” said Associate Professor Marcus Ong, Senior Consultant, Department of Emergency Medicine, SGH and lead investigator of the study.

“The SCDF is constantly studying ways to enhance its pre-hospital care management. In terms of patient-care, Penthrox or Tramadol can potentially allow us to bring pain relief further forward into the field and potentially reduce the suffering of the patients faster and more effectively. We look forward to working with SGH in the evaluation study of the two medications” said LTC (Dr) Ng Yih Yng, Chief Medical Officer, Singapore Civil Defence Force.

“It is good that patients can now get pain relief from injuries or other acute conditions in a pre-hospital setting before seeing the doctors at the A&E departments. This is done in a timely, safe and efficacious manner, driven by expert protocols” said Associate Professor Goh Siang Hiong, Chairman, Medical Advisory Committee.

To evaluate the efficacy of the pain relief medications, patients will be asked to rate their own pain on a scale of 1 to 10 at 5, 10, 15 and 20 minutes after intervention. The sedation scores and patient’s satisfaction will also be recorded along with a review of their Emergency Department and hospital records for any medication related adverse effects.


About Penthrox (Methoxyflurane) and Tramadol  

Penthrox is a clear, almost colourless liquid with a fruity smell that patients can inhale from a custom-built inhaler. Pain relief should start after six to 10 breaths and the patient controls the amount of pain relief that he or she receives. A 3ml bottle of Penthrox can give about 20 to 25 minutes of pain relief. If required, a second bottle can be given to extend the pain relief effect to about 50 to 55 minutes. Penthrox has not been used in Singapore but is extensively used in the pre-hospital setting in Australia.

Tramadol is also a clear, colourless solution but is given by an injection into the vein or muscle. It is a common pain relief medication used in the hospital setting and comes in the form of a 2ml 1ml ampoule. Each ampoule contains 50mg of Tramadol. An injected dose of 50mg is effective for four to six hours. It is used extensively in all Emergency Departments across the island, well-proven, simple to deliver but has not been used in Singapore ambulances.

Both Penthrox and Tramadol may cause nausea or drowsiness.