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N 2O is included in prehospital management protocols for manipulation, splinting and transfer
of patients with lower limb fracture (Lee & Porter, 2005 Level IV) and as a second‐line in burns
patients if opioids are not available (Allison & Porter, 2004 Level IV). Although N 2O has been
reported to provide pain relief in over 80% of patients requiring prehospital analgesia (Thomas
& Shewakramani, 2008 Level IV), this is not based on RCTs (Faddy & Garlick, 2005) and there are
few studies comparing efficacy with other agents. In one paediatric series, a higher proportion
of children receiving N 2O rather than opioids had pain on arrival in the emergency
department, but interruption of delivery during transfer from the ambulance may have
contributed (Watkins, 2006 Level IV). Based on data from hospital studies, N 2O has been
suggested as a safe analgesic in prehospital settings, although specific contra‐indications (such
as pneumothorax and decreased consciousness) may be particularly relevant in this patient
group (Faddy & Garlick, 2005) (see Section 4.3.1 for further details).
Ketamine
Ketamine has been administered by physicians for prehospital procedural analgesia and
sedation in both adults (Porter, 2004 Level IV; Svenson & Abernathy, 2007 Level IV; Bredmose, Lockey
et al, 2009 Level IV) and children (Bredmose, Grier et al, 2009 Level IV) with good safety profile.
Non-steroidal anti-inflammatory drugs and paracetamol
The use of parenterally administered NSAIDs has been suggested for prehospital analgesia
(Alonso‐Serra & Wesley, 2003; McManus & Sallee, 2005) but the slower onset of effect as well as
the risk of adverse effects (eg bleeding, renal impairment [see Section 4.2]), especially in
patients who have lost blood and may be hypovolaemic, means they are not commonly used.
Similarly injectable paracetamol is not commonly used. Oral paracetamol or other analgesics
have a limited role in the acute prehospital setting.
9.10.2 Anxiolytics

Anxiolytics, for example low doses of midazolam, are sometimes used to alleviate some of the
acute anxiety or agitation that may complicate effective control of pain in stressful prehospital
conditions (McManus & Sallee, 2005). However, there are no studies looking at efficacy and
safety. It should be remembered that their combination with opioids will increase the risk of
respiratory depression and that anxiety and agitation may be indicators of other more serious
underlying conditions such as a head injury or hypoxia (McManus & Sallee, 2005).

9.10.3 Regional analgesia CHAPTER 9
Use of regional analgesia in the prehospital setting (excluding war or disaster situations) is
uncommon. Initiation of a fascia iliaca block for analgesia in patients with isolated femoral
shaft fractures provided effective pain relief prior to arrival at an emergency department
(Lopez et al, 2003 Level IV).
9.10.4 Non-pharmacological management of pain

Although analgesic agents are often used to treat pain in the prehospital setting, the
importance of non‐pharmacological treatments should not be forgotten. These include ice,
elevation and splinting for injuries. The role of reassurance in the management of acute pain in
an anxious patient is often undervalued.
TENS applied over the painful flank during prehospital transport reduced pain scores, anxiety
and nausea in patients with renal colic (Mora et al, 2006 Level II).

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