Reduction of Anterior Shoulder Dislocation Facilitated by Inhaled Low Dose Methoxyflurane
Condition: Shoulder Dislocation
MeSH terms: Joint Dislocations; Shoulder Dislocation
Study type: Interventional

Summary: 
      This pilot study will test the feasibility of doing a definitive study to ascertain whether
      reduction of shoulder dislocation can be safely and effectively facilitated by a patient
      controlled inhalational analgesic, negating the need for potentially dangerous PSA and the
      use of intravenous therapy. The hypothesis includes that time to reduction and time spent in
      the emergency department will be reduced.
    

Detailed description: 
      Anterior shoulder dislocation, in which the head of the humerus (cup) comes out of its
      position in the glenoid fossa (saucer), to lie anterior and below its proper position, is a
      common emergency department presentation. Between April 1, 2011 and March 31, 2018, 1654
      patients presented to emergency departments in Emergency Departments of the Central Zone of
      the Nova Scotia Health Authority (Average 236/year). The treatment of dislocated shoulder
      involves reduction to a normal anatomical position as soon as possible, to manage pain and
      disability and to minimize the chance of poor long term outcome. Numerous methods exist to
      effect reduction, most of which are conducted under procedural sedation and analgesia (PSA)
      that allows the shoulder muscles to relax so that they do not hold the humeral head in a
      dislocated position. PSA involves the administration of intravenous sedatives and narcotic
      analgesics. Not only do the medications carry the risk of respiratory depression and
      hypotension, but their duration of action results in longer emergency department stays and
      the use of intravenous lines, is invasive and adds patient discomfort and expense to the
      procedure. An additional risk of PSA in this specific population is that reduction of the
      dislocation to its normal position, immediately removes the painful stimulus that antagonizes
      the respiratory depression of the sedative and analgesic agents. This often results in
      unopposed respiratory depression which might be unrecognized as the 'crisis' appears to be
      over with the restoration of the shoulder joint. Furthermore, PSA requires specifically
      trained staff and space; and time taken to arrange PSA prolongs the time during which the
      humerus is out of position. It has been reported that from the time of arrival in the
      emergency department with an anterior shoulder dislocation, every 10 min delay in reduction
      attempt increased the odds of a failed reduction attempt by 19%. In the Charles V. Keating
      Emergency and Trauma Centre in Halifax, Nova Scotia, PSA is conducted by specially trained
      advanced care paramedics using standard preparation, monitoring and recovery protocols. In an
      effort to painlessly reduce shoulder dislocations without PSA, the Cunningham technique has
      been described, which involves massaging the shoulder muscles in an attempt to get them to
      relax sufficiently to allow reduction. Although this method does work, and has been
      associated with decreased need for PSA, it is associated with an increase in the rate of
      unsuccessful first reduction attempts. After unsuccessful attempts using the Cunningham
      technique, the fallback is generally to then provide PSA, increasing the time to reduction.
      Inhaled low-dose methoxyflurane has been used for several decades in Australia as an
      emergency analgesic for short-term use. Administered via a portable, disposable, single-use
      hand-held inhaler device administered by the patient for pain relief, it offers a safe and
      effective non-opioid alternative to morphine. Inhaled methoxyflurane has been shown to be
      safe, effective, and simple to administer in obstetric patients during childbirth, as well as
      for patients with bone fractures and joint dislocations, and for dressing changes on burn
      patients. In 2018, PenthroxTM (methoxyflurane) received marketing authorization from Health
      Canada for adult patients requiring short-term relief from moderate to severe acute pain
      associated with trauma or interventional medical procedures. Low dose methoxyflurane adds to
      the armamentarium of Canadian emergency care providers as an option that is relatively
      inexpensive, safe and very easy to administer rapidly. As most failures of the Cunningham
      anterior shoulder reduction method are due to patient discomfort, the investigators
      hypothesize that inhaled low dose methoxyflurane has the potential to increase first attempt
      success rates using this method while decreasing the time from arrival to reduction, the need
      for intravenous therapy or the use of potentially dangerous medications. The Penthrox
      inhalers will be supplied by Purdue and will be stored in the emergency department in a
      locked cabinet in a locked box with limited access. It is a self controlled inhaled
      medication controlled by each inhalation. Each breath a patient takes releases a fraction of
      the single dose contained in the inhaler.
    

Intervention name(s): Methoxyflurane
Intervention type(s): Device
Intervention description(s): Methoxyflurane (Penthrox) inhaler, 3mL inhalation vapour, liquid
Other intervention name(s): Penthrox
Intervention MeSH terms: Methoxyflurane
Intervention model: Single Group Assignment
Intervention model description: This prospective open-label pilot study will examine the use of inhaled low dose methoxyflurane to facilitate shoulder reduction in a convenience sample of patients arriving with anterior shoulder dislocations. This study will test the feasibility of studying the addition of this analgesic agent to a reduction technique that classically eschews procedural sedation in order to increase successful reduction rates. Consenting eligible patients will be offered a first attempt at reduction using the method described by Cunningham, supported by self-administered low-dose methoxyflurane analgesia as instructed by the advanced/critical care paramedic. For unsuccessful first attempts, patients will then undergo the current standard of care for shoulder dislocations, which is reduction of the shoulder joint while under procedural sedation and analgesia.
Masking: None (Open Label)
Primary purpose: Other