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Trial registered on ANZCTR


Registration number
ACTRN12617000830392
Ethics application status
Approved
Date submitted
31/05/2017
Date registered
6/06/2017
Date last updated
7/05/2018
Type of registration
Prospectively registered

Titles & IDs
Public title
Effect of intraoperative magnesium on the incidence of chronic post surgical pain after thoracotomy
Scientific title
Effect of intraoperative magnesium on the incidence of chronic post surgical pain after thoracotomy
Secondary ID [1] 292098 0
None
Universal Trial Number (UTN)
U1111-1197-1970
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Chronic post-thoracotomy pain 303519 0
Condition category
Condition code
Surgery 302931 302931 0 0
Other surgery
Anaesthesiology 302942 302942 0 0
Pain management

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The aim of this study is to investigate the effects of intraoperative systemic magnesium on chronic postsurgical pain in patients undergoing thoracotomy. A bolus dose of 50mg/kg of magnesium (magnesium sulfate) will be administered for 15 minutes immediately after induction and prior to skin incision, followed by infusion at 10mg/kg/hr which will be continued until the patient has been transferred to the Post Anaesthesia Care Unit (PACU).
Intervention code [1] 298240 0
Treatment: Drugs
Comparator / control treatment
Patients in the control group will be administered and infused the same volume of isotonic saline.
Control group
Placebo

Outcomes
Primary outcome [1] 302323 0
Assess the incidence of chronic post surgical pain at 2 and 6 months post thoracotomy.

This will be done via a telephone call from a pain nurse at 2 and 6 months post thoracotomy. A simple yes/no categorical outcome will be used and patients reporting pain will be asked to present to a chronic pain clinic for further assessment by an anaesthetist. At this visit, a 0-10 point numeric rating scale (NRS) will be used to measure the degree of pain intensity.
Timepoint [1] 302323 0
2 and 6 months post operation

2 months post operation is the primary endpoint
Secondary outcome [1] 335490 0
Evaluate the duration of hospital stay
Timepoint [1] 335490 0
At hospital discharge
Secondary outcome [2] 335491 0
Evaluate intraoperative opioid requirements (in morphine equivalents) by reviewing the anaesthetic record.
Timepoint [2] 335491 0
At surgery completion
Secondary outcome [3] 335492 0
Evaluate opioid/local anaesthetic requirements (converted to morphine and ropivacaine equivalents).

This will be done by evaluating analgesic requirements which will have been documented on standard hospital pain protocol forms.
Timepoint [3] 335492 0
Opioid/local anaesthetic requirements will be assessed at 24 and 48 hours post surgery
Secondary outcome [4] 335493 0
Characterise the intensity and type of CPSP. This is a composite secondary outcome. A 0-10 point numeric rating scale (NRS) will be used to measure the degree of pain intensity. Type of CPSP will be assessed using the Neuropathic Pain Questionnaire (NPQ).
Timepoint [4] 335493 0
2 and 6 months post thoracotomy
Secondary outcome [5] 335621 0
Evaluate postoperative pain scores. Pain scores will be measured using a 0-10 point numeric rating scale (NRS).
Timepoint [5] 335621 0
This will be done at 24 and 48 hours post surgery.
Secondary outcome [6] 335622 0
Health related quality of life

This will be assessed using the Medical Outcome Study 36-Item Short Form (SF-36). This form will be sent to all participants. The SF-36 is a widely used instrument that is standardized and validated. It assesses eight scales: physical functioning, role functioning-physical, bodily pain, general health, energy, social functioning, role functioning-emotional, and mental health.
Timepoint [6] 335622 0
6 months post thoracotomy

Eligibility
Key inclusion criteria
18 to 80 years of age, male or female gender, scheduled for elective thoracotomy surgery, ASA physical status class I to III, body mass index <40kg/cm2
Minimum age
18 Years
Maximum age
80 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Allergy to magnesium sulfate, major hepatic or renal failure, presence of neurologic disease, second or third degree atrioventricular block, pre-existing treatment with magnesium or calcium channel blockers. Patients with chronic neuropathic pain due to any cause will also be excluded from this clinical trial.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Block randomisation and sealed envelope method
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Permuted block randomisation
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s

Intervention assignment
Parallel
Other design features
Phase
Type of endpoint(s)
Statistical methods / analysis

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
QLD
Recruitment hospital [1] 8226 0
The Townsville Hospital - Douglas
Recruitment postcode(s) [1] 16283 0
4814 - Douglas

Funding & Sponsors
Funding source category [1] 296629 0
Government body
Name [1] 296629 0
Queensland Health
Address [1] 296629 0
Townsville Hospital
100 Angus Smith Drive
Douglas 4814
QLD
Country [1] 296629 0
Australia
Primary sponsor type
Individual
Name
Antimony Mar
Address
Townsville Hospital
100 Angus Smith Drive
Douglas 4814
QLD
Country
Australia
Secondary sponsor category [1] 295592 0
None
Name [1] 295592 0
None
Address [1] 295592 0
None
Country [1] 295592 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 297861 0
Townsville Hospital
Ethics committee address [1] 297861 0
Ethics committee country [1] 297861 0
Australia
Date submitted for ethics approval [1] 297861 0
26/05/2017
Approval date [1] 297861 0
21/09/2017
Ethics approval number [1] 297861 0

Summary
Brief summary
Chronic post surgical pain (CPSP) is a recognised and adverse outcome of many surgical procedures. It was first reported by Macrae and Davis and is defined as “pain persisting for at least two months duration following a surgical procedure”. Other causes for the pain and the possibility that the pain is from a pre-existing condition should be excluded before classifying the pain as CPSP. The prevalence of CPSP varies depending on the operation with higher rates observed after major thoracic surgery. In fact, patients undergoing thoracotomy have one of the greatest incidences of CPSP among all surgical procedures.

The etiology of chronic post-thoracotomy pain is not understood fully. It is thought to result from potential intercostal nerve damage. As there is also a component of neuropathic pain, rather than inflammatory or nociceptive pain, central sensitisation is likely involved. Central sensitisation relies on N-methyl-D-aspartate (NMDA) receptor activation by excitatory neurotransmitters, such as glutamate and aspartate. Studies have shown that NMDA receptor antagonists, such as ketamine, can decrease CPSP. In theory, magnesium, which is a physiologic antagonist of NMDA receptors, should prevent central sensitisation and therefore reduce the incidence of CPSP.


The aim of this study is to investigate the effects of intraoperative systemic magnesium on chronic postsurgical pain in patients undergoing thoracotomy. We propose to perform a single centre, prospective, double-blind, placebo-controlled study over the period of one year. Our hypothesis is that intra-operative systemic administration of magnesium will reduce the incidence of CPSP in patients undergoing thoracotomy.

On the morning of surgery, block randomisation and sealed envelope method will be used to assign patients to one of the two groups: magnesium group or control group. The anaesthetist, surgeon, patient and those assessing outcomes will be blinded to the group assignment. A bolus dose of 50mg/kg of magnesium (magnesium sulfate) will be administered for 15 minutes immediately after induction and prior to skin incision, followed by infusion at 10mg/kg/hr. Patients in the control group will be administered the same volume of isotonic saline.

Patients will be assessed on postoperative day 1 and 2 by a pain team (includes anaesthetist and pain nurse). A 0-10 point numeric rating scale (NRS) will be used to measure the degree of pain intensity. Higher scores indicate a higher degree of pain. Postoperative opioid consumption (24 hours and 48 hours) will also be recorded by converting to the equivalent dose of intravenous morphine.

Patients will be assessed at 2 and 6 months post surgery. This will be done via a telephone call from a pain nurse. Patients reporting pain will be asked to present to a chronic pain clinic for assessment by an anaesthetist. All patients will be asked to complete a Medical Outcome Study 36-Item Short Form to assess health related quality of life.
Trial website
Trial related presentations / publications
Public notes
Attachments [1] 2665 2665 0 0
/AnzctrAttachments/373060-SSA_17_QTHS_149_1 Approval.pdf (Supplementary information)
Attachments [2] 2666 2666 0 0
/AnzctrAttachments/373060-HREC17QTHS102_4 AM01.pdf (Ethics approval)

Contacts
Principal investigator
Name 75298 0
Dr Christopher Butler
Address 75298 0
Townsville Hospital
100 Angus Smith Drive
Douglas 4814
QLD
Country 75298 0
Australia
Phone 75298 0
+61744331111
Fax 75298 0
Email 75298 0
Chris.Butler@health.qld.gov.au
Contact person for public queries
Name 75299 0
Dr Antimony Mar
Address 75299 0
Townsville Hospital
100 Angus Smith Drive
Douglas 4814
QLD
Country 75299 0
Australia
Phone 75299 0
+61744331111
Fax 75299 0
Email 75299 0
Antimony.Mar@health.qld.gov.au
Contact person for scientific queries
Name 75300 0
Dr Antimony Mar
Address 75300 0
Townsville Hospital
100 Angus Smith Drive
Douglas 4814
QLD
Country 75300 0
Australia
Phone 75300 0
+61744331111
Fax 75300 0
Email 75300 0
Antimony.Mar@health.qld.gov.au

No information has been provided regarding IPD availability
Summary results
No Results