What are the anesthetic considerations for parathyroid resection?
It is important to know the indication for the surgery. If the patient has secondary hyperparathyroidism from end-stage renal disease, it is important to consider all the impli-cations of renal failure and its comorbidities. These patients are likely to have hypertension, diabetes mellitus, and coronary artery disease, as well as metabolic derange-ments from renal failure.
For patients presenting with primary hyperparathy-roidism, it is important to know the calcium concentration and whether the patient is symptomatic. Hypercalcemia causing significant symptoms should be corrected preop-eratively. Isolated parathyroid adenomas that have been localized preoperatively can be excised under general anes-thesia, regional anesthesia with unilateral deep and super-ficial cervical blocks, or sedation and local anesthesia. The experience and comfort level of the surgeon and patient expectations play a large role in the choice of anesthetic plan. Surgery for all four glands or for poorly localized ade-nomas is more easily performed under general anesthesia. It is difficult to obtain adequate regional anesthesia bilat-erally. Bilateral deep cervical plexus blocks can cause bilateral recurrent laryngeal nerve paralysis or bilateral phrenic nerve paralysis, and are relatively contraindicated. More surgeons are becoming comfortable with performing bilateral neck exploration under local anesthesia.
It is now commonplace to monitor PTH levels before and after adenoma resection. After successful resection, PTH levels should fall by half within 10 minutes. A large-bore intravenous catheter in an antecubital vein usually provides adequate blood flow to obtain specimens. Alternatively, it is sometimes necessary to place a catheter in a foot, or perform repeat venipuncture in a foot to obtain specimens. Rarely, an arterial line can be placed for the case, but the risk-benefit ratio must be carefully con-sidered. The arms are usually tucked by the patient’s side and are inaccessible during surgery.