Anesthesia Considerations & Management: 70-Year-Old with Hyperthyroidism, HTN, T2DM - Clavicle Surgery

I. PREOPERATIVE ASSESSMENT

A. Systems-Based Evaluation

1. Hyperthyroidism

• Check TSH, free T3, free T4. If TSH is suppressed and T3/T4 elevated, postpone surgery.
• Surgery and anesthesia can precipitate thyroid storm in patients with uncontrolled or undiagnosed hyperthyroidism - this is a life-threatening complication (Morgan & Mikhail's, 7e).
• Review current anti-thyroid medications (PTU, methimazole, carbimazole). Continue these perioperatively.
• Check for signs of end-organ effects: atrial fibrillation, high-output cardiac failure, ophthalmopathy, goiter (airway!), skeletal myopathy, osteoporosis.
• ECG: look for AF, sinus tachycardia, LVH, ischemic changes.
• Beta blocker optimization: propranolol 40-80 mg PO TID or atenolol - must be continued perioperatively. If not on a beta blocker, consider starting one 1 week before surgery to blunt tachycardia.
• Anesthesia induction may be slower and may require higher concentrations of inhaled anesthetics due to elevated cardiac output in hyperthyroid patients (Current Surgical Therapy, 14e).

2. Hypertension

• Review current antihypertensives - ACEi/ARBs, beta blockers, calcium channel blockers, diuretics.
• Continue all antihypertensives perioperatively (especially beta blockers - abrupt cessation risks rebound).
• ACEi/ARBs: hold on morning of surgery only if concerned about intraoperative hypotension (common practice), or continue if BP poorly controlled - discuss with surgeon/cardiologist.
• Target: BP < 180/110 mmHg before proceeding with elective surgery. If higher, optimize first.
• Assess for end-organ damage: LVH on ECG/echo, renal function, retinopathy.
• Labs: BMP (K+, creatinine), HbA1c.

3. Type 2 Diabetes

• Check HbA1c, fasting glucose, recent trends.
• Ideal HbA1c < 8.5% for elective surgery; > 9% significantly increases perioperative risk.
• Identify medications: metformin (hold 24-48 hrs preop to reduce lactic acidosis risk, especially with contrast or prolonged NPO), sulfonylureas (hold night before - hypoglycemia risk), SGLT2 inhibitors (hold 3-5 days preop - euglycemic DKA risk), insulin (usually reduce basal dose 50-80% on day of surgery).
• Monitor blood glucose perioperatively - target 140-180 mg/dL intraoperatively.
• Assess for autonomic neuropathy (baroreceptor dysfunction - clinically silent hypotension), gastroparesis (aspiration risk!), peripheral neuropathy, renal impairment.
• Diabetic autonomic neuropathy is a key concern: both HTN and DM in a 70-year-old substantially raise this risk. These patients can have wide hemodynamic swings and reduced heart rate variability (Barash, 9e).

4. Age-Related (70 Years)

• Reduced physiologic reserve: diminished cardiac, pulmonary, renal, hepatic reserves.
• Polypharmacy - drug interactions.
• Reduced MAC requirement for volatile anesthetics (approximately 6% decrease per decade after 40).
• Higher sensitivity to benzodiazepines and opioids - cognitive effects, prolonged sedation.
• Reduced renal clearance - adjust renally-cleared drugs.
• Risk of postoperative cognitive dysfunction (POCD) and postoperative delirium.
• Poor thermoregulation - active warming required.

B. Investigations Required

C. NPO Status

• Standard: clear liquids up to 2 hours, solids 6-8 hours.
• Gastroparesis (DM): consider extending NPO, consider sodium citrate + metoclopramide preoperatively.

II. ANTIBIOTIC PROPHYLAXIS - ALLERGY MANAGEMENT

• Penicillins (amoxicillin included)
• Cephalosporins (standard prophylaxis - cefazolin - is contraindicated)
• Levofloxacin (fluoroquinolone)
• Sulfonamides

• Per Barash (9e): "Those with a proven allergy to penicillin, cephalosporins, and related compounds (beta-lactam allergy) may receive either vancomycin or clindamycin."
• Per Campbell's Operative Orthopaedics (15e 2026): Severe beta-lactam allergy → Clindamycin 900 mg IV q8h; add vancomycin 15 mg/kg IV q12h if MRSA colonization known.
• At 70 years, assess MRSA risk (prior hospitalizations, nursing home, prior MRSA). If high-risk: use vancomycin preferentially or add to clindamycin.
• Red Man Syndrome with Vancomycin: pre-treat with diphenhydramine 25-50 mg IV, infuse slowly over 90 min.
• Aztreonam can be used for gram-negative coverage if wound contamination is a concern (clean clavicle surgery generally does not need gram-negative coverage).

III. ANESTHETIC TECHNIQUE

A. Regional Anesthesia - First Choice for Clavicle Surgery

• The clavicle is innervated by:
  • Supraclavicular nerves (C3-C4, cervical plexus) - medial and lateral clavicle
  • Brachial plexus (C5-C6 via interscalene) - acromioclavicular joint area
• For complete clavicle anesthesia: ISB alone is often insufficient; a combined interscalene block + superficial cervical plexus block is recommended.
• Benefits for this patient: avoids GA risks in a compromised patient, less hemodynamic perturbation, excellent postoperative analgesia, reduces opioid requirements.

• Phrenic nerve palsy (100% incidence with classical ISB) - causes ipsilateral hemidiaphragm paresis. If the patient has pulmonary reserve issues, this is a concern. For most patients with clavicle surgery it is tolerable.
• If phrenic nerve palsy is a concern, consider a low-volume ISB (5-10 mL) or alternative approaches.

B. Sedation / Monitored Anesthesia Care (MAC)

• Regional block + light sedation is ideal for this patient.
• Use dexmedetomidine for sedation - provides analgesia + anxiolysis, minimal respiratory depression, sympatholytic (helpful in HTN + hyperthyroidism), no increase in MAC.
• Avoid high-dose midazolam/propofol as sole sedatives in elderly - cognitive effects.
• Dose reductions for sedatives in 70-year-old - use 30-50% dose reduction for midazolam and propofol.

C. General Anesthesia (if required)

Induction

• Propofol 1-1.5 mg/kg (reduced dose in elderly; titrate to effect)
• Alternatively: etomidate 0.2-0.3 mg/kg if hemodynamically unstable (caution: inhibits cortisol synthesis - single dose usually acceptable; not ideal in hyperthyroid patients)
• Ketamine: generally avoided in hyperthyroidism - sympathomimetic effects can trigger tachycardia, hypertension, potentially thyroid storm.
• Thiopental: reduces T3 conversion (useful in hyperthyroid) but not commonly available.

Airway Management

• Check for goiter: tracheal deviation or compression? May complicate laryngoscopy.
• Have video laryngoscope available.
• Succinylcholine 1-1.5 mg/kg for RSI if needed (higher risk of aspiration with gastroparesis). Note: hyperthyroidism can be associated with myopathy; however succinylcholine is generally safe unless significant muscle weakness is present.
• Rocuronium 0.6-1.2 mg/kg (with sugammadex reversal available) is preferred.

Maintenance

• Volatile agents (sevoflurane/isoflurane preferred): titrate to BIS 40-60 in elderly.
  • In hyperthyroid patients, inhalational induction is slower and higher concentrations needed (elevated cardiac output).
  • Avoid halothane (sensitizes myocardium to catecholamines - dangerous in hyperthyroid state).
• Desflurane: avoid - tachycardia and sympathetic stimulation on high concentrations.
• Sevoflurane: preferred volatile agent.
• Total IV Anesthesia (TIVA) with propofol: acceptable alternative.
• Nitrous oxide: can be used with caution; no specific contraindication.

Intraoperative Monitoring

• Standard ASA monitors: SpO2, ETCO2, BP (5-minute intervals), ECG (continuous), temperature.
• Arterial line: strongly recommended given HTN + hyperthyroid + DM - for beat-to-beat BP monitoring and blood gas/glucose sampling.
• Urine output monitoring for longer procedures.
• Temperature monitoring: essential - hyperthyroid patients are at risk of hyperpyrexia; thyroid storm can mimic malignant hyperthermia intraoperatively (Miller's Anesthesia, 10e).

IV. INTRAOPERATIVE MANAGEMENT

A. Hemodynamic Goals

• Avoid tachycardia (target HR < 80-90 bpm) - tachycardia in a hyperthyroid patient is dangerous (can precipitate storm, myocardial ischemia).
• Maintain BP within 20% of baseline.
• Avoid sympathetic stimulation - adequate analgesia and anesthetic depth.
• Esmolol infusion (50-200 mcg/kg/min) if tachycardia develops intraoperatively - drug of choice for acute rate control.
• Labetalol for acute hypertensive episodes.
• Have vasopressors ready: phenylephrine or norepinephrine for hypotension (ephedrine also acceptable; in hyperthyroid patients, pure alpha agents preferable to avoid reflex tachycardia).

B. Fluid Management

• Avoid dextrose-containing solutions (monitor glucose carefully).
• Use balanced crystalloids (Lactated Ringer's or PlasmaLyte).
• Monitor glucose every 1-2 hours intraoperatively.
• Target glucose 140-180 mg/dL.

C. Prevention of Thyroid Storm

• Uncontrolled pain/anxiety - ensure adequate premedication and analgesia.
• Sympathetic surges - titrate anesthetic depth carefully.
• Hypothermia (paradoxically increases sympathetic drive on rewarming) - active warming.
• Recognize thyroid storm vs. malignant hyperthermia (differential diagnosis intraoperatively):
  • Both: hyperthermia, tachycardia, elevated CO2
  • Thyroid storm: responds to beta blockade, antithyroid drugs, steroids
  • MH: responds to dantrolene, no response to beta blockers

1. Propylthiouracil (PTU) 500-1000 mg loading, then 250 mg PO/NG q4h
2. Potassium iodide (SSKI) - 5 drops PO q8h - give 1-2 hours AFTER PTU
3. Propranolol or esmolol IV for rate control
4. Hydrocortisone 100-300 mg IV (reduces T4 to T3 conversion, covers relative adrenal insufficiency)
5. Acetaminophen for fever (NOT aspirin - displaces T4 from TBG)
6. Active cooling
7. Correct metabolic derangements (glucose, electrolytes)

V. POSTOPERATIVE MANAGEMENT

A. Recovery (PACU)

• Monitor ECG continuously - watch for new AF, tachycardia.
• Blood glucose monitoring q1h until stable.
• Temperature monitoring - hyperthyroid patients may run febrile.
• Adequate analgesia - regional block provides excellent coverage; supplement with acetaminophen.
• Avoid NSAIDs in elderly with DM and HTN - risk of renal impairment.
• Resume all preoperative medications as soon as possible (especially antithyroid drugs, antihypertensives, insulin).
• Metformin: restart only after confirming adequate renal function and oral intake.
• SGLT2 inhibitors: restart when eating normally.

B. Multimodal Analgesia

• Acetaminophen 1g IV/PO q6h - preferred (safe in all comorbidities)
• Regional block continuation (if catheter placed)
• Opioids (tramadol, morphine, fentanyl) - use sparingly in elderly, monitor carefully
• Avoid NSAIDs (HTN, DM, renal risk)

C. Discharge Criteria

• Euthyroid baseline HR (< 100 bpm)
• BP within 20% of baseline
• Blood glucose 100-200 mg/dL
• No signs of thyroid storm
• Adequate pain control
• Tolerating oral medications/food

VI. SUMMARY CHECKLIST

• Morgan & Mikhail's Clinical Anesthesiology, 7e - thyroid storm perioperative management
• Barash Clinical Anesthesia, 9e - antibiotic prophylaxis with allergy, autonomic dysfunction
• Miller's Anesthesia, 10e - intraoperative thyroid storm, MH differentiation
• Campbell's Operative Orthopaedics, 15e (2026) - orthopedic antibiotic prophylaxis with beta-lactam allergy

• Levofloxacin (allergic - documented)
• Ofloxacin - contraindicated (same class)
• Ciprofloxacin - contraindicated (same class)
• Moxifloxacin - contraindicated (same class)
• Norfloxacin - contraindicated (same class)

• Clindamycin 900 mg IV (first choice for clean orthopedic surgery with beta-lactam allergy)
• Vancomycin 15 mg/kg IV (if MRSA risk or as combination)

• Weight-based: 15 mg/kg IV
• 15 mg/kg × 38 kg = 570 mg IV

Which dose to use?

• Clindamycin vials come in 150 mg/mL concentration
• 600 mg = 4 mL of the standard vial - convenient to prepare
• 900 mg in a 38 kg patient = 23.7 mg/kg - this is above the standard 15 mg/kg weight-based dose and may increase risk of side effects (hypotension, GI effects) in a frail elderly patient

Administration

• Infuse over 20-30 minutes (rapid infusion causes hypotension and neuromuscular blockade - especially relevant in an anesthetized patient)
• Give 30-60 minutes before skin incision
• No repeat dose needed for clavicle surgery (short duration, clindamycin half-life ~2-3 hours; redose only if surgery > 6 hours)