Is bradycardia a risk in patients undergoing lumbar surgery?

Bradycardia Risk in Lumbar Surgery

Bradycardia can occur during lumbar surgery, but the risk is primarily related to patient characteristics and anesthetic technique rather than the lumbar surgery itself, with spinal/epidural anesthesia carrying a similar bradycardia risk to general anesthesia. 1, 2

Understanding the Risk Profile

Patient-Related Risk Factors

The 2018 ACC/AHA/HRS guidelines identify specific patient characteristics that increase bradycardia risk during any noncardiac surgery, including lumbar procedures 3:

• Age >60-65 years significantly increases risk 3, 4
• Baseline heart rate <60 bpm 3, 4
• ASA Class III or IV comorbidities 3
• Baseline blood pressure <110/60 mmHg 3
• Concurrent use of beta-blockers or renin-angiotensin system blockers 3, 4

Mechanism of Bradycardia in Lumbar Surgery

In noncardiac surgery settings, intraoperative bradycardia is most commonly attributable to sinus node dysfunction (SND) and only rarely due to worsening atrioventricular conduction 3. This is distinct from procedure-specific vagal reflexes seen with carotid surgery or trigeminal nerve manipulation 3.

Anesthetic Technique Considerations

Spinal/Epidural Anesthesia

Multiple meta-analyses demonstrate that spinal or epidural anesthesia does NOT increase bradycardia risk compared to general anesthesia for lumbar spine surgery 1, 2:

• A 2017 meta-analysis of 625 patients found no evidence of difference in intraoperative bradycardia between spinal and general anesthesia (risk ratio 0.51 for tachycardia, but no significant bradycardia difference) 1
• A 2023 updated meta-analysis of 733 patients confirmed no significant differences in bradycardia incidence between regional and general anesthesia 2
• Bradycardia incidence with spinal anesthesia is approximately 4.9% overall, with risk factors including age and sensory level ≥T4 5

General Anesthesia

Hemodynamically significant bradycardia and cardiac arrest during spine surgery under general anesthesia are rare but documented 6:

• A case series identified temporal relationships with somatosensory evoked potential (SSEP) stimulation in 4/6 cases of significant arrhythmia 6
• Polypharmacy and specific anesthetic agents may contribute 6

Clinical Management Algorithm

Preoperative Risk Assessment

For high-risk patients (meeting ≥2 risk factors above), the ACC/AHA/HRS guidelines recommend (Class IIa) 3:

1. Placement of transcutaneous pacing pads is reasonable before surgery begins 3, 4
2. Review and consider holding negative chronotropic medications 4
3. Ensure atropine is immediately available 4
4. Plan for continuous heart rate monitoring 4

Intraoperative Management

If bradycardia develops during lumbar surgery 4:

• Stop any provocative maneuvers temporarily and allow patient recovery 4
• Ensure adequate oxygenation and ventilation 4
• Administer atropine 0.5-1 mg IV for persistent bradycardia, repeatable every 3-5 minutes up to 3 mg maximum 4
• Onset of action occurs within 3 minutes after IV administration 4

Important Caveat

Routine prophylactic temporary transvenous pacing should NOT be performed (Class III: Harm) even in patients with left bundle branch block requiring pulmonary artery catheterization, as the incidence of complete heart block is low and prophylactic pacing carries increased risk of ventricular arrhythmias 3.

Key Clinical Pitfalls

• Do not assume lumbar surgery itself causes bradycardia - the risk stems from patient factors and anesthetic management, not the surgical site 3, 1
• Do not routinely place transvenous pacing wires - transcutaneous pads are sufficient for high-risk patients 3
• Do not overlook SSEP stimulation as a potential trigger during neuromonitoring in spine surgery 6
• Spinal anesthesia is not contraindicated due to bradycardia concerns - it offers comparable safety with additional benefits including reduced hypertension and tachycardia 1, 2