Magnesium Sulfate, Postoperative Pain, Opioid Use
Conditions
Keywords
Postoperative pain, opioid, Postoperative analgesia
Brief summary
Magnesium sulfate has been shown to be useful in many situations in medicine, such as eclampsia prevention and treatment, pulmonary hypertension, arterial pressure, asthma, cardiac arrhythmias and pheochromocytoma. Recently there has been a growing a big interest in this drug as an useful adjuvant in anesthesia, with analgesic and anesthetic sparing effect, antihyperalgesic property and potentialization of the neuromuscular blocker agent effect. On the other hand there has been a growing concern related to opioid administration, such as hyperalgesia, delayed return of intestinal function and the (still controversial) possibility of facilitating effect on tumor growth and metastases in cancer patients. This project is based on a previous randomized, double blind prospective trial (conducted by one of these authors and not yet published) comparing two groups of patients who received general intravenous total anesthesia with propofol in controlled target infusion. The surgical stress index is obtained by the interaction between the interval between heart beats and the amplitude of the photoplethysmography wave, whose algorithm generates a number related to the hemodynamic result of the increase of the sympathetic tone, which has shown to be the most sensitive resource in detecting the imbalance between the stimulus nociceptive and anti-nociception.
Detailed description
Magnesium sulfate has been shown to be useful in many situations in medicine, such as eclampsia prevention and treatment, pulmonary hypertension, arterial pressure, asthma, cardiac arrhythmias and pheochromocytoma. Recently there has been a growing a big interest in this drug as an useful adjuvant in anesthesia, with analgesic and anesthetic sparing effect, antihyperalgesic property and potentialization of the neuromuscular blocker agent effect. On the other hand there has been a growing concern related to opioid administration, such as hyperalgesia, delayed return of intestinal function and the (still controversial) possibility of facilitating effect on tumor growth and metastases in cancer patients. This project is based on a previous randomized, double blind prospective trial (conducted by one of these authors and not yet published) comparing two groups of patients who received general intravenous total anesthesia with propofol in controlled target infusion. The surgical stress index is obtained by the interaction between the interval between heart beats and the amplitude of the photoplethysmography wave, whose algorithm generates a number related to the hemodynamic result of the increase of the sympathetic tone, which has shown to be the most sensitive resource in detecting the imbalance between the stimulus nociceptive and anti-nociception. Objectives The main objective of this project is to evaluate the feasibility of the use of magnesium sulfate in replacement of remifentanil as the main analgesic agent in total venous general anesthesia in patients submitted to post-bariatric dermolipectomy surgery. The secondary objectives will be comparison of propofol consumption, time to onset of action, time of action and cisatracurium consumption between groups. We will evaluate pain scores in the immediate postoperative period and in the mornings and afternoons of the 3 days after surgery.
Interventions
Venous general anesthesia with propofol and remifentanil.
Venous general anesthesia with propofol and magnesium sulfate
Sponsors
University of Sao Paulo General Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Masking description
The anesthesiologist in charge of randomization will number 40 opaque envelopes and insert a card in each with the corresponding information of the group (according to the lottery) and the medication to be administered. Another anesthesiologist in charge of preparing the blind solution alone will open the envelope. Both of these investigators, as well as the anesthesiologist providing anesthesia and the anesthesiologist in charge of data evaluation will not participate in any of the other steps of the trial. The patients will be blinded to their own treatment group.
Intervention model description
Prospective, controlled, randomized and double-blind clinical trial.
Eligibility
Sex/Gender
ALL
Age
18 Years to 18 Years
Healthy volunteers
No
Inclusion criteria
* age 18 to 60 year-old * body mass index \< 35 kg/m² * American Society of Anesthesiologists score \< III * agreement to participate and sign the informed consent form.
Exclusion criteria
* Allergy to any medications of the trial * neuromuscular diagnosed disorder * cardiac conduction blockade (atrioventricular block II or higher), * use of illicit drugs * use of calcium channel blockers * creatinine \> 2 mg/dl.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Feasibility of using magnesium sulfate as analgesic of venous general anesthesia | Surgery time | Changes in systolic blood pressure (mmHg) after tracheal intubation and surgical incision in both groups. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Anesthetic consumption. | During surgery | Consumption of propofol (mg) and cisatracurium. |
| Neuromuscular blocker action | During surgery | Onset and offset of cisatracurium (minutes) |
| Postoperative pain | Three days | Pain scores (verbal numerical scale from 0 to 10). |
Countries
Brazil
Outcome results
None listed