Remifentanil sedation for parathyroidectomy

Conscious sedation techniques are increasing in popularity with the availability of ultra short-acting drugs. Most surgical procedures require analgesia with or without sedation to achieve patient acceptability. We report the case of a 40-year-old woman who presented with a 12-year history of hyperparathyroidism (calcium levels of 3.3–3.5 mmol.l−1 and parathyroid hormone levels of 173 pmol.ml−1). A left lower parathyroid adenoma was identified by systemebi and ultrasound scans. The patient was keen to avoid general anaesthesia and hence a parathyroidectomy under local anaesthesia with sedation was planned. Continuous remifentanil infusions, titrated to the expected surgical stimulus, have been used as conscious sedation for many different procedures. We routinely use this technique for procedures such as awake fibreoptic intubation, hysteroscopy and trans-vaginal tension-free sling. In well-motivated patients undergoing awake minimally invasive surgery, remifentanil has proved to be very effective. Our patient received no premedication, supplementary oxygen was supplied via a nasal catheter and intravenous access was established. Ondansetron 4 mg was given prophylactically. Remifentanil was infused at a variable rate between 0.03 and 0.2 µg.kg−1.min−1. A total of 8 ml of bupivacaine 0.25% with 1 : 200 000 epinephrine was infiltrated during the 40-min procedure. In recovery, the patient confirmed that she had been comfortable throughout the operation and was extremely pleased with the whole experience. In our practice we find remifentanil provides excellent analgesia and sedation, which is titratable. The side-effects we commonly encounter with awake remifentanil sedation are hypoventilation and nausea. The hypoventilation is easily countered by encouraging the patients to breathe and hence it is essential to maintain verbal contact with the patient at all times. Nausea can be largely prevented by prophylactic anti-emetics.