EDITOR:
Postoperative pain, nausea and vomiting are the main obstacles for ambulatory breast surgery. Although the cause of postoperative nausea and vomiting (PONV) is multifactoral, appropriate pain management during and after surgery is essential for its prevention [Reference Rawal1,Reference Chung and Mezei2]. Regional blocks, including thoracic paravertebral, thoracic epidural and intercostal nerve blocks applied before the incision, are known to provide prolonged analgesia and decrease the incidence of PONV in breast surgery [Reference Terheggen, Wille, Borel Rinkes, Ionescu and Knape3]. Their main disadvantages, however, are failure rate, risk of complications, need for specific skills and time required. These potential drawbacks outweigh the benefits in patients with breast carcinoma undergoing lumpectomy with or without sentinel node biopsy [Reference Terheggen, Wille, Borel Rinkes, Ionescu and Knape3].
In order to start an ambulatory breast cancer surgery programme with a high level of patient satisfaction, we evaluated the usefulness of a simple post-induction, pre-surgery, ipsilateral field block for the reduction of postoperative pain, nausea and vomiting in patients scheduled for lumpectomy with or without sentinel node biopsy under general anaesthesia.
Our Institutional Medical Ethics Committee approved this study. ASA I or II female patients scheduled in the period from March 2004 to June 2004 for lumpectomy with or without sentinel node biopsy received general anaesthesia, as was the routine at that time (GA group). Propofol was the induction agent along with a short-acting inhalational agent (desflurane or sevoflurane), sufentanil in titrated doses and atracurium or vecuronium as needed for muscle relaxation. Matched female patients scheduled for a similar procedure in the period from October 2004 to December 2004 received, after informed consent and absence of contra-indications, a similar general anaesthesia and a field block of the breast (GA + LA group). The field block was given after the induction of general anaesthesia and before the start of the surgical procedure. Contra-indications were allergy to amide-type local anaesthetics and infection at the injection site. A field block consisted of deep subcutaneous infiltration with ropivacaine 0.5% alongside the caudal border of the clavicle (supraclavicular nerves), alongside the ipsilateral parasternal line (anterior cutaneous branches of the first to sixth intercostal nerves), and along a line 1 cm posterior and parallel to the anterior axillary line extending under the fold of the pectoralis major muscle high in the axilla (lateral cutaneous branches of the second to seventh intercostal nerves). The total volume of ropivacaine varied between 32 and 60 mL depending on patient body weight. All infiltrations were performed with several 20-mL syringes attached at a 20-G Quincke-type spinal needle.
All patients received 75 mg diclofenac intravenously before the surgical incision. In both study groups, the laryngeal mask airway or endotracheal tube was removed in the operating room when the patient was fully awake before transport to the post-anaesthesia care unit (PACU). Postoperative treatment consisted of a fixed schedule of 1000 mg acetaminophen (paracetamol) combined with 50 mg diclofenac at 8-h intervals, supplemented with opioid rescue medication if needed. A visual analogue scale was used to assess pain and a score greater than 3 (on a scale from 0 to 10) was considered as inadequate analgesia. Trained nurses collected data in both groups prospectively in the recovery room and afterwards on the ward. Rescue opioid medication was given at any time during the first 24 h postoperatively, if the pain score exceeded 3.
PONV was defined as nausea or vomiting or retching at any time during the first 24 h postoperatively. All patients who received any opioids at any time during the first 24 h after surgery were considered opioid-rescue-medication positive. The two groups were analysed and compared based on the following data:
1. pain measured by visual analogue scale (0–10) on arrival at the post-anaesthetic care unit;
2. number of patients with PONV during the first 24 h after surgery;
3. number of patients who need opioid rescue medication. Data are expressed as median (range) or as number of patients and were analysed by Wilcoxon two-sample test or Fisher’s exact test when appropriate.
We included 36 patients in the GA group and 24 in the GA + LA group. Contra-indications for amide-type local anaesthetics or refusal for field block were absent. All patients recovered uneventfully and had no adverse events (ECG disturbances, hypertension, hypotension, bradycardia or tachycardia) during anaesthesia and surgery or signs of local anaesthetic systemic toxicity, or mental confusion in the PACU. Nine patients (25%) in the GA group vs. one (4%) in the GA + LA group suffered from nausea in the first 24 h after surgery (P = 0.04). No patient from the GA + LA group vomited during the first 24 h after surgery but six patients in the GA group vomited (P = 0.07)
Pain score on arrival at the PACU was 3.5 in the GA group vs. 0 in the GA + LA group (P = 0.00015). Eighteen (50%) patients in the GA group vs. 1 (4%) in the GA + LA group had a pain score >3 on arrival at the PACU. Opioid rescue medication during the first 24 h after surgery was necessary in 18(50%) patients in the GA group vs. 5(20%) in the GA + LA group (P = 0.031).
The incidence of PONV after breast surgery under general anaesthesia is high and its aetiology is complex [Reference Rawal1,Reference Chung and Mezei2]. Appropriate pain management during and after the operation remains a keystone in the prevention of PONV [Reference Chung and Mezei2]. Its incidence is reduced by regional block techniques, which provide a long-term analgesic effect after surgery [Reference Rawal1]. However, in breast surgery, the commonly used thoracic epidural and paravertebral blocks need specific skills. They are time consuming and have complications including pneumothorax or accidental dural puncture. Therefore they are less appropriate for minor breast surgery [Reference Terheggen, Wille, Borel Rinkes, Ionescu and Knape3].
We used a simple post-induction, pre-surgery field block as descripted by Niesel [4].
This technique is comparable with that used for herniorrhaphy under general anaesthesia supplemented by peripheral nerve block [Reference Tverskoy, Cozacov, Ayache, Bradley and Kissin5].
There were no signs of systemic toxicity in any patients treated with local anaesthetics, but adverse effects are difficult to identify under general anaesthesia in the absence of ropivacaine blood-concentration measurements. However, no mental confusion was noticed in patients during the PACU period, and cardiovascular disturbances were absent during both anaesthesia and the peri-operative period. Ropivacaine was chosen because of its superior toxicological profile compared to bupivacaine in humans [Reference Knudsen, Suurküla, Blomberg, Sjövall and Edvardsson6]. The maximum dose of 300 mg ropivacaine, which was given to a female weighing 85 kg, was similar to those reported as routine in brachial plexus block for a patient of a similar body weight [Reference Janzen, Vipond, Bush and Hopkins7].
In the absence of a routine preventative anti-emetic regimen and despite the use of opioids and volatile anaesthetics that promote PONV, the reduction of nausea in the small GA + LA group was statistically significant (P = 0.04). Remarkably, only patients in the GA group vomited; possibly because of the greater number of patients who needed opioid rescue medication. The difference in vomiting was not statistically significant probably due to the relatively small number of patients. With respect to postoperative wellbeing and functional recovery, similar results have been reported after local infiltration anaesthesia before the incision in patients with inguinal herniorrhaphy [Reference Tverskoy, Cozacov, Ayache, Bradley and Kissin5].
Regional blocks have been reported to have an advantage over general anaesthesia in breast surgery in terms of postoperative nausea, vomiting and opioid use [Reference Terheggen, Wille, Borel Rinkes, Ionescu and Knape3]. Although this was not a randomized controlled trial comparing general anaesthesia with and without additional field block, the potential benefits of a field block in patients undergoing lumpectomy with or without sentinel node biopsy under general anaesthesia became clear.
In conclusion, this comfortable and simple technique may have potential for clinical anaesthesia care, especially for ambulatory breast surgery. Its value in breast surgery warrants further study.
