Thyroidectomy in Patient with Hypertension A 38 year old man is scheduled for thyroid goiter surgery. He has a history of hypertension and has been on metaproterenol and captopril. BP: 180/110, PR: 80/min ECG no specific ST-T changes. Case 65

Preoperative Evaluation ► History: symptoms of hyperthyroidism such as anxiety, fatigue, heat intolerance, diarrhea, dyspnea, and palpitations ► PE: BP, T, HR(tachycardia?), rhythym(tachydysrhythmias?), goiter, Thyrotoxic myopathy(proximal weakness), exophthalmos ► PMH: Hypertension, asthma

Preop/Labs/Tests ► TSH, T3, T4  Is patient euthyroid? ► CBC, LFT, ECG ► CT neck, flow-volume loops  Airway obstruction?

Preop Medication ► Clonidine  Will blunt sympathetic nervous response ► Midazolam ► No anticholinergics  Interfere with heat regulation and contribute to increased heart rate

Induction Anesthesia/Muscle Relaxants ► Thiopental  Thiourea structure with antithyroid activity ► NDNM or succinyl choline

Alternate Intubation Plan ► Awake intubation with fentanyl

Maintenance Anesthetic Agents ► Sevoflurane/nitrous oxide mixture  Suppresses sympathetic nervous system ► Possibly avoid Desflurane  Large bolus can cause transient increase in sympathetic activity ► Alternate is short-acting opioid/nitrous oxide  However, does not reliably suppress sympathetic nervous system.

Intraoperative Medical Care ► Thyroid storm, which mimics malignant hyperthermia, can consist of hyperthermia, tachycardia, CHF, low intravascular volume, and shock  Chilled crystalloid infusion  Continuous esmolol infusion  Propylthiouracil, methimazole, NaI  If persistent hypotension, then Dexamethasone ► Inhibits T4 to T3 conversion  No aspirin ► Increases level of free T4 ► Elevated BP  Esmolol

Early Postoperative Care ► Thyroid storm usually occurs 6-18 hrs post-op ► Other Complication:  Recurrent laryngeal nerve injury  Hematoma  Tracheomalacia  Hypoparathyroidism  Superior laryngeal nerve injury ► Pain management - PCA