Abstract ID: A26
Abstract Title: The hemodynamic stability of remifentanil as an adjunct to thyroid and parathyroid surgery under cervical plexus blockade
Poster Type: Either
ABSTRACT BODY
Introduction:Surgery of the thyroid or parathyroids (T or P) is increasingly being performed using cervical plexus blockade (CPB), thus avoiding airway manipulations and providing postoperative analgesia. Remifentanil (R), an ultra-short acting narcotic, offers analgesia and sedation that are easily titratable during procedures in which there is limited access to patients’ airways. This is a retrospective review of the use of remifentanil as an adjunct to surgery of the T or P performed under CPB.
Materials and Methods:After receiving IRB approval, computerized anesthesia records (CompuRecord® Philips, Andover, MA) were queried for all patients undergoing surgery of T or P under CPB for 43 months. Data retrieved included patient demographics, surgical procedure, block technique and maximal R rates. Supplemental analgesics, and episodes of apnea and need for conversion to general anesthesia (GA) were noted. All of these parameters were compared to patients who underwent similar procedures under GA.
Results:Ninety-seven patients (24.9%) underwent T or P surgery with CPB. Patients were premedicated with midazolam < .03 mg/kg with or without fentanyl < 1.5 μg/kg or Rl <.05 μg/kg/min. Regional anesthesia consisted of bilateral superficial CPB (12-15 cc local anesthetic/block) and a deep CPB (single injection at C4, 10 cc local anesthetic/block) on the side with pathology, or that perceived as more difficult by the surgeon. Local anesthetics included 1% lidocaine or 1.5% mepivacaine, with or without 0.5% bupivacaine. 99% of patients received R as an adjunct and all had it begun prior to the block. Infusion rates ranged from .03 to .15 μg/kg/min. There were 5 cases, which were converted to GA: 2 secondary to surgical reasons, 2, secondary to patient anxiety and 1, secondary to local anesthetic toxicity. One patient had subjective complaints of dyspnea, without objective correlation, and one was treated for bradycardia. Five patients had transient episodes of apnea (loss of EtCO2 with a drop in O2 saturation >5%) and 13 had transient episodes of hypoxia (< O2 saturations but no loss of respiration.) 100% of these episodes coincided with the onset of or increase in the R infusions. There were 2 (2.1%) episodes of hypotension (MAP<60 or drop in MAP >20%, treated with pressors). Among the 292 procedures performed with GA, there were 89 episodes (30.5%) of hypotension, with 57 (19.5%) requiring treatment with ephedrine or phenyelphrine. One patient vomited on extubation, one had intraoperative bronchospasm requiring bronchdilator therapy, and one had bradycardia.
Discussion:T or P surgery requires deep GA to provide analgesia as well as to prevent the stimulation of the endotracheal tube. Studies confirm the safety of both deep and superficial CPBs for carotid procedures (1,2), as well as analgesic adjuncts for T or P surgery (3,4), but CPB as primary anesthetic for them is infrequently described. We have confirmed CPB as a well tolerated primary anesthetic for T and P surgery, as well as demonstrating the hemodynamic advantages of using R as an adjunct.
References:(1) Emery. Anesth Int Care 1998;26:377. (2) Lee. J Neurosurgery 1988;69:483. (3) Dieudonne. Anesth Analg 2001;92:1538. (4)Aumac. Anesth Analg 2002;95:746.
ATTACHED FILES
Reg Anesth Pain Med 2004; 29(2):A26