Clinical Trial – Dexmedetomidine for Sedation in Total Knee Replacements
Dexmedetomidine has demonstrated benefits both in sedation, and post-operative pain control,
with less respiratory depression than other common sedatives. Traditionally, dexmedetomidine
has been used with a large loading dose and infusion, which has been known to cause
dose-dependent negative side-effects (Abdallah et al., 2013). Single dose dexmedetomidine
produces less negative side-effects, but still effective sedation and reduced post-operative
pain (Jung et al., 2013). There is evidence for its benefits with general anesthesia but only
a few studies exist investigating its benefits when administered for sedation purposes with
spinal anesthesia, and no studies primarily examine post-operative opioid consumption. The
investigators hypothesize that single dose dexmedetomidine for procedural sedation will
reduce opioid consumption after total knee arthroplasty (TKA).
Clinical Trial – HBOT Late Radiation Tissue Injury
Background: Radiotherapy is a common treatment for many malignancies. Radiation-related
complications developing months or years after radiation treatment are known as late
radiation tissue injury (LRTI) and are estimated to effect 5%-15% of all long-term survivors
who have received radiation.
Hyperbaric oxygen therapy (HBOT) is a well established treatment of LRTI. Most of the studies
evaluating effect of HBOT on LRTI are focused on survival, resolution of tissue damage and
improvement in LENT-SOMA scale. Very few studies have addressed effect of HBOT on pain in
LTRI. Krahn and colleagues were the first to report the analgesic effect of HBOT in 3 cases
of refractory pain in oncological patients with radiation soft tissue injury. Other studies
showed significant improvement in pain intensity in patients with breast cancer and pelvic
malignancies treated with HBOT for LTRI. In patients that had developed radiation- induced
brachial plexopathy, HBOT elicited an increase in warm pain thresholds and a reduction in
lymphoedema. A prospective case study of 16 patients with gynecological cancer found no
changes with respect to pain and depression outcomes. A trial in patients with radiation
induced proctopathy showed that 75% of patients with rectal pain had some improvement,
although none experienced a complete resolution of pain symptoms.
There are several mechanisms by which HBOT may elicit analgesic effects. There is a growing
body of evidence that HBOT’s analgesic effect related to nitric oxide metabolism and
endogenous opioid secretion. Furthermore, the inhibition of tumor necrosis factor alph
(TNF-α), the production of substance P, and the modulation of serotonergic pathways have all
demonstrated a modification in the pain response following HBOT. In animal studies HBOT
decreased allodynia and hyperalgesia in different models of neuropathic and inflammatory
pain. The long lasting antinociceptive effect of HBOT was found to be dose-dependent in
non-injured tissues.
In human studies, HBOT decreased pain and edema and improved function in patients suffering
from the complex regional pain syndrome, and improved pain scores and range of motion in
patients with idiopathic femoral head necrosis. Women suffering from interstitial cystitis
demonstrated a reduction in pelvic pain following weeks and months of HBOT treatment. In
patients suffering from idiopathic trigeminal neuralgia HBOT produced a rapid reduction in
symptoms and these effects were lasting for 6 months following treatment. HBOT was also found
to be an effective treatment for cluster headaches and migraines and alleviated muscle and
bone pains in patients with myofascial syndrome, fibromyalgia, and biphosphonate-related
osteonecrosis of the jaw.
Based on the evidence presented above and HBOT’s known analgesic effect in many conditions,
the investigators designed this study with the objective to evaluate if HBOT reduces pain,
improves depression and impacts on patients quality of life in patients suffering from late
radiation tissue injury.
Study Design: Prospective observational study (n=300). Patients that have had radiation
therapy for malignancy, developed late radiation injury and suffer from chronic pain.
Clinical Trial – HBOT in Fibromyalgia
Fibromyalgia (FM) is a chronic pain condition affecting several millions of Canadians.
Although the etiology and pathophysiology are poorly understood, there is a well-recognized
association between muscular pain in fibromyalgia and muscular hypoperfusion, hypoxia,
abnormal muscle metabolism and oxidative stress. Currently there is no cure for FM.
Pharmacological and non-pharmacological strategies are directed to control symptoms such as
pain, fatigue, non-restorative sleep and depression.
Hyperbaric oxygen therapy (HBOT) is an intermittent inhalation of 100% oxygen in a hyperbaric
chamber at a pressure higher than 1 absolute atmosphere. Physiological effect of HBOT is
based on a dramatic increase in the amount of dissolved oxygen carried by the blood which
enables oxygenation of ischemic areas with compromised circulation. It also activates
oxidant-antioxidant system, stimulates angio- and neurogenesis, modulates inflammatory
response, induces brain neuroplasticity and possesses analgesic effect.
While some interventions offer benefit for some patients, additional treatment alternatives
are needed for patients with FM in whom currently available options are either ineffective or
poorly tolerated. Given its physiological effect, HBOT could be considered as a potential
therapy for treatment of underlying muscular hypoxia, optimizing oxidant- antioxidant system
and controlling FM symptoms. The results from this study could therefore provide new
information supporting the basic science underling the pathophysiology of this disease and
stimulate novel therapies for patients suffering with FM.