Thoracic paravertebral block for breast surgery.

Abstract

Anaesthesia and surgery during pregnancy may produce intense psychological and physiological stress in the peri-operative period that may pose a threat to the well being of the mother and the fetus. We wish to report the management of the surgical excision of a breast tumour with axillary lymph node dissection in a pregnant woman under thoracic paravertebral blockade (TPVB) and sedation. A 24 year-old primigravida at 19 week gestation was admitted to the hospital with a 2.2 cm tumour of the left breast and non-palpable axillary nodes. After discussion of the anaesthetic options with the patient, a decision was made to proceed with TPVB and sedation. After establishing monitoring and starting supplemental oxygen via nasal cannulae, ranitidine 50 mg, midazolam 1 mg and fentanyl 50 µg were administered intravenously. With the patient in the sitting position, left TPVB was performed at T1 to T7 by injecting 5 ml of 0.5% ropivacaine at each level, using the technique described by Greengrass and Steele [1]. Following the TPVB the patient was placed in the supine position with a left lateral tilt and a superficial cervical nerve block was performed using 0.5% ropivacaine 5 ml. A few minutes later the sensory block was confirmed by loss of sensation to cold and pinprick of the appropriate dermatomes and an infusion of propofol 25 µg.kg−1.min−1 was commenced. A wide local excision of the tumour with lymph node dissection was carried out. During the 65 min operation the patient remained comfortable and communicative. No anaesthetic complications or side-effects including nausea or vomiting were noted. Morphine PCA and paracetamol were used for postoperative analgesia. The total analgesic requirement was morphine 12 mg and paracetamol 5 g for the first 48 h. The pain VAS scores were recorded every 4 h and remained < 20 mm on mobilisation (0 = no pain and 100 = the worst imaginable pain). She was discharged on the third postoperative day in good condition. At 34 week gestation the patient underwent elective Caesarean section under spinal anaesthesia and delivered a healthy child. Up to 2% of pregnant women undergo general anaesthesia for surgical procedures not related to pregnancy [2]. General anaesthesia administered during the first two trimesters of pregnancy for gynaecological procedures is associated with a high incidence of miscarriage [3]. Furthermore, there is a risk of premature labour associated with the stress of anaesthesia and surgery. The fetus may be exposed to teratogenic effects of drugs, the severity of which depends on the dose of the drug, the stage of development, and the genetic susceptibility of the fetus [4]. Studies suggest that administration of local anaesthetics to pregnant women will not have deleterious effects on fetal development and neonatal outcome. Ropivacaine administered as an intravenous infusion in pregnant ewes did not cause any important changes in the mother or the foetus and the foetal well-being was not affected [5]. TPVB is safe and effective for major breast surgery [6], and is associated with a low overall incidence of complications and provides a high degree of patient satisfaction [7]. Hypotension is uncommon after TPVB in normovolemic patients because of unilateral sympathetic blockade, but TPVB may unmask hypovolemia. The long lasting postoperative analgesia after bolus injections of TPVB (mean duration 23 h, range 9–38 h) in contrast to bolus thoracic epidural analgesia is a further benefit [7]. The good postoperative analgesia provided by the balanced regimen of local anaesthetics, paracetamol and morphine, together with the elimination of the cortical responses to thoracic dermatomal stimulation as a result of the TPVB [8], probably protected our patient from pain and nausea and vomiting during the postoperative period. The management of breast surgery during pregnancy may be complex. TPVB is a simple and safe alternative technique that offers anaesthesia as well as prolonged postoperative analgesia with minimal side-effects.