What is the optimal pre‑operative and peri‑operative management of tachycardia in an 8‑year‑old girl scheduled for thyroidectomy?

Perioperative Management of Tachycardia in an 8-Year-Old Undergoing Thyroidectomy

Before proceeding with thyroidectomy in an 8-year-old with tachycardia, you must first exclude and treat pheochromocytoma if MEN 2 syndrome is suspected, as failure to do so can precipitate hypertensive crisis during surgery. 1

Preoperative Evaluation and Risk Stratification

Screen for Underlying Thyroid-Related Causes

• Rule out hyperthyroidism and thyroid storm as the primary driver of tachycardia, particularly if the child has Graves' disease or toxic adenoma requiring thyroidectomy. 2, 3
• Assess for signs of thyrotoxicosis including fever, diaphoresis, hypertension, tremor, and emotional lability, which indicate inadequate disease control and increased perioperative risk. 2
• Delay elective surgery if thyrotoxicosis is uncontrolled, as proceeding increases the risk of thyroid storm with mortality implications. 2

Exclude Pheochromocytoma in Suspected MEN 2 Syndrome

• If medullary thyroid carcinoma or MEN 2 syndrome is suspected, pheochromocytoma must be excluded preoperatively through biochemical testing and imaging. 1
• Pheochromocytomas must be removed with laparoscopic adrenalectomy before thyroidectomy, with preoperative α-adrenergic blockade (phenoxybenzamine) or α-methyltyrosine to prevent hypertensive crisis during surgery. 1
• After α-blockade and forced hydration are established, β-adrenergic blockade may be added to treat tachyarrhythmia associated with pheochromocytoma. 1

Obtain Baseline Cardiac Assessment

• Obtain a 12-lead electrocardiogram to characterize the rhythm, exclude myocardial ischemia, and identify any underlying conduction abnormalities. 1, 4
• Assess for structural heart disease or inherited arrhythmia syndromes if tachycardia is persistent or unexplained, as these may require specialized perioperative management. 1

Preoperative Optimization

Correct Reversible Causes of Tachycardia

• Optimize pain control, as inadequate analgesia perpetuates tachycardia through heightened sympathetic tone. 5, 6
• Correct electrolyte abnormalities, particularly maintaining serum potassium ≥4.0 mmol/L and replenishing magnesium, as these are common triggers for tachyarrhythmias. 5, 6, 4
• Ensure adequate hydration and rule out hypovolemia, which can cause compensatory tachycardia. 5, 6
• Optimize oxygenation, as hypoxemia is a frequent trigger for postoperative tachycardia. 5, 6

Pharmacologic Rate Control When Indicated

• Beta-blockers are the first-line agents for ventricular rate control in hemodynamically stable pediatric patients with tachycardia, including atrial fibrillation and supraventricular tachycardia. 1, 5, 6, 4
• Beta-blockers reduce heart rate through direct chronotropic inhibition and accelerate conversion of supraventricular arrhythmias to sinus rhythm compared to calcium-channel blockers. 1, 5, 6
• If beta-blockers are contraindicated, non-dihydropyridine calcium-channel blockers (diltiazem or verapamil) may be used as an alternative. 1, 5, 6
• Esmolol is FDA-approved for rapid control of ventricular rate in perioperative atrial fibrillation/flutter and for intraoperative/postoperative tachycardia, making it particularly suitable for this setting. 7

Intraoperative Management

Continuous Monitoring and Immediate Response

• Maintain continuous electrocardiographic monitoring throughout the procedure to detect arrhythmias promptly. 1, 4
• Have external defibrillation equipment readily available for patients at risk of unstable tachyarrhythmias. 5, 4

Treat Intraoperative Tachycardia Systematically

• First evaluate for reversible causes including inadequate anesthesia depth, hypovolemia, hypoxemia, or electrolyte abnormalities rather than immediately administering antiarrhythmics. 1, 4
• Beta-blockers remain first-line pharmacologic treatment for intraoperative tachycardia in hemodynamically stable patients. 4, 7
• Esmolol is specifically indicated for short-term treatment of tachycardia during induction, intubation, surgery, emergence from anesthesia, and the postoperative period. 7

Postoperative Management

Peak Risk Period and Monitoring

• Continuous electrocardiographic monitoring through postoperative days 2-3 is reasonable, as atrial fibrillation incidence peaks at approximately 2.5 days postoperatively in thoracic surgery patients. 5
• Extended monitoring should be considered for patients with multiple risk factors for arrhythmias. 5

Systematic Approach to Postoperative Tachycardia

• Systematically evaluate for reversible causes including pain, hypovolemia, hypoxemia, and electrolyte abnormalities before initiating antiarrhythmic therapy. 5, 6
• Aggressive analgesia (intercostal nerve blocks, local anesthetic infiltration, or patient-controlled analgesia) should be instituted promptly, as pain is the most frequent reversible driver. 5
• Beta-blockers are the preferred first-line agents for postoperative tachycardia in hemodynamically stable patients. 5, 6

Rhythm-Specific Management

For supraventricular tachycardia:

• Begin with vagal maneuvers (Valsalva, carotid sinus massage). 5
• If vagal attempts fail, administer intravenous adenosine. 5
• Third-line therapy includes intravenous calcium-channel blockers or beta-blockers. 5

For atrial fibrillation/flutter:

• Prioritize rate control over immediate electrical cardioversion. 5
• Do not cardiovert minimally symptomatic atrial fibrillation until underlying reversible factors are corrected, as spontaneous conversion is common and cardioversion rarely maintains sinus rhythm in this setting. 5

For ventricular arrhythmias:

• Assess for myocardial ischemia, electrolyte disturbances, and drug effects before initiating therapy. 5
• Therapeutic options include intravenous beta-blockers, lidocaine, procainamide, or amiodarone, selected according to hemodynamic status and underlying etiology. 5, 6

Special Pediatric Considerations

Surgical Expertise and Team Approach

• Pediatric thyroidectomy should be performed by high-volume thyroid surgeons as part of a multidisciplinary team including pediatric endocrinologists and anesthesiologists, given higher complication rates in children compared to adults. 3, 8
• Children <6 years have greater incidence of respiratory and infectious complications, suggesting a need for closer monitoring and possibly routine postoperative intensive care unit utilization. 8

Common Pitfalls to Avoid

• Asymptomatic premature ventricular contractions should not be treated with antiarrhythmic drugs unless they cause hemodynamic compromise, as they are not linked to increased perioperative cardiac events. 1, 5
• Do not proceed with thyroidectomy if pheochromocytoma has not been excluded in suspected MEN 2 cases, as this can be fatal. 1
• Avoid cardioversion of postoperative atrial fibrillation before correcting reversible factors, as most episodes convert spontaneously. 5