SUPplementary REgional anesthesia in MAmma surgery (SUPREMA trial).

Rationale:
The incidence of postoperative nausea and vomiting (PONV) varies from 20 to 80% in patients undergoing mamma surgery. PONV are strongly related to postoperative pain.
PONV are also well known side effects of opioids. Appropriate pain management during and after surgery without, or with a lower dose of opioids, may decrease the incidence of PONV. Earlier studies with different surgical operations showed that combining general anesthesia with regional infiltration anesthesia with a long acting local anesthetic provided superior and prolonged analgesia, compared with general anesthesia alone.
Therefore, regional infiltration anesthesia of the mamma with a long acting local anesthetic could provide better analgesia in mamma surgery under general anesthesia compared to the same surgery under general anesthesia alone. This may lead to decreased incidence of PONV and decreased postoperative use of opiates and anti-emetics. Ropivacaine is chosen as a long acting local anesthetic because of its superior toxicological profile compared to bupivacaine.


Hypothesis:
In mamma surgery, regional infiltration anesthesia with ropivacaine 0,75% added to general anesthesia causes less postoperative pain, nausea and vomiting compared to general anesthesia alone.


Study design:
Double blind, placebo controlled randomized intervention study.
Study population: Women scheduled in the Reinier de Graaf Groep for single-sided breast conserving surgery with or without sentinel node biopsy.


Intervention:
Regional infiltration anesthesia of the ipsilateral breast with ropivacaine 0,75% (maximum volume 0,47 ml/kg) or placebo (a comparable volume of NaCl 0,9%).
The regional infiltration consists of deep subcutaneous infiltration parallel to the clavicle, in the ipsilateral parasternal line and in a line parallel to and 0-1 cm posterior of the ipsilateral anterior axillary line. The infiltration trajects are from medial to lateral alongside the clavicle and from caudal to cranial at the trunk.


Main objectives:

Primary objectives:

Postoperative vomiting in the first 24 hours.

Secondary objectives:

postoperative nausea at entry in the recovery room and 4, 8 and 24 hours after surgery
postoperative pain at entry in the recovery room and 4, 8 and 24 hours after surgery
need for postoperative opiates (frequency and total dose in first 24 hours),
need for postoperative anti-emetics (frequency and total dose in first 24 hours).


Nature and extent of the burden and risks associated with participation, benefit and group relatedness:

The burden associated with participating consists of three subcutaneous injections with a total maximum dose of 3,5 mg/kg (0,47 ml/kg) of ropivacaine 0,75% or the same volume of NaCl 0,9%. Injections will be given under general anesthesia (which is already part of operating procedure).

Participation in this study includes side effects of infiltration anesthesia: inadvertent intravascular injection, bleeding in the infiltration traject and ipsilateral pneumothorax or numbness in the ipsilateral arm, due to brachial plexus involvement. Side effects of ropivacaine use are mostly caused by systemic administration (when inadvertently injected intravascular) and include convulsions, hypotension and nausea. Hypotension and nausea are in general frequently seen with operations and it is impossible to distinguish them as side effects of the clinical situation from side effects of the drug or field block.
The risk of these side effects can be minimized by thorough training of the anesthesiologists participating in the study.

The incidence of postoperative nausea and vomiting (PONV) varies from 20 to 80% in patients undergoing mamma surgery. PONV are strongly related to postoperative pain.
PONV are also well known side effects of opioids. Appropriate pain management during and after surgery without, or with a lower dose of opioids, may decrease the incidence of PONV. Earlier studies with different surgical operations showed that combining general anesthesia with regional infiltration anesthesia with a long acting local anesthetic provided superior and prolonged analgesia, compared with general anesthesia alone.
Therefore, regional infiltration anesthesia of the mamma with a long acting local anesthetic could provide better analgesia in mamma surgery under general anesthesia compared to the same surgery under general anesthesia alone. This may lead to decreased incidence of PONV and decreased postoperative use of opiates and anti-emetics. Ropivacaine is chosen as a long acting local anesthetic because of its superior toxicological profile compared to bupivacaine.

1. At entry recovery room;

2. 4, 8 and 24 hours after end of surgery.

Regional infiltration anesthesia of the nerve branches of the mamma subjected to surgery with ropivacaine 0,75% (maximum volume 0,47 ml/kg) or placebo (a comparable volume of NaCl 0,9%).
The regional infiltration consists of deep subcutaneous infiltration parallel to the clavicle, in the ipsilateral parasternal line and in a line parallel to and 0-1 cm posterior of the ipsilateral anterior axillary line. The infiltration trajects are from medial to lateral alongside the clavicle and from caudal to cranial at the trunk.