Introduction
Current practice in Singapore Emergency Ambulance Service (EAS) includes the use of analgesia
delivered via inhalation Enthanox (Nitrous Oxide). However there are difficulties
administering Enthanox on-scene due to the added weight of carrying bulky cylinder tanks. It
is common for a delay in administration of analgesia. Inhaled methoxyflurane (Penthrox) is a
potential agent for early administration of analgesia by Singapore Civil Defense Force (SCDF)
EAS. It is extensively used in the pre-hospital setting in Australia. However data on its use
as an analgesic agent in general are limited and there are few published controlled trials of
methoxyflurane in an analgesic role. Intramuscular (IM) tramadol is a common medication used
in the hospital setting for analgesia. It is well proven, simple to deliver and is not a
controlled drug.
Aim
To compare Penthrox and Tramadol in the treatment of acute pain in patients transported by
the SCDF EAS.
Methodology
The trial will recruit 400 eligible patients over 1 year (200 Penthrox and 200 tramadol).
Patients managed by SCDF EAS for treatment of acute pain and who meet the eligibility
criteria will be recruited into the study. Half of SCDF's 30 ambulances (15 ambulances), will
be randomly assigned, equipped and trained to carry the new medication (Penthrox). The other
half (15 ambulances), will be trained and equipped with tramadol. Allocation will be on a per
station level. After 6 months, they will cross over to Penthrox and tramadol respectively.
All paramedics will be trained to use both medications, pain scales and Ramsey scores, and
will record patient's pain, sedation scores and patient satisfaction as part of routine
clinical practice. All patients will be followed up by a review of their Emergency Department
and hospital records for any medication related adverse effects.
Hypothesis
The investigators hypothesize that in patients with acute pain (pain score ≥3), presenting to
the ambulance service with musculo-skeletal trauma (limbs or back); pain relief by inhaled
methoxyflurane will be equivalent to IM tramadol, as assessed by Visual Analogue Scale (VAS)
at 5, 10, 15 and 20 min after start of the study treatments.