Enhancing the Effect of Stellate Ganglion Block in the Treatment of Posttraumatic Stress Disorder: A Double-blind Randomized Controlled Trial of Bupivacaine vs Bupivacaine + Ketamine

Inclusion Criteria: 1. DSM-5 diagnosis of PTSD of at least moderate severity confirmed by PCL-5 score ≥33 or CAPS-5 score ≥26 at screening visit 2. Age 18-69 years 3. Under care of a mental health clinician 4. Has not benefited from pharmacological and/or psychological evidence-based treatments for PTSD Exclusion Criteria: 1. Assessed with high risk for suicide in the last 30 days 2. Active mania/ hypomania or psychosis within the last 30 days 3. Moderate to severe substance use within the last 30 days 4. In process of disability assessment or legal action 5. Current participation in another treatment study for PTSD 6. Pregnancy or breastfeeding confirmed by urine test 7. Current anticoagulant use (eligible if can be held before the procedure) 8. History of bleeding disorder 9. Infection, mass or anatomic abnormalities at target injection site 10. Myocardial infarction within 6 months of procedure 11. Pathologic bradycardia or irregularities of heart rate or rhythm; 12. Symptomatic hypotension 13. Phrenic or laryngeal nerve palsy 14. History of glaucoma 15. Uncontrolled seizure disorder 16. History of allergy to local anesthetics 17. History of allergy to general anesthetics 18. Severe chronic obstructive pulmonary disease (COPD) 19. Current or reoccurring Pneumothorax 20. Contralateral pneumonectomy or non-functional lung 21. Active systemic infection 22. Bilateral procedure is always contraindicated due to risk of laryngeal/phrenic nerve dysfunction 23. Participant refusal/inability to tolerate procedure/positioning 24. End stage renal disease 25. Known allergy to Ketamine 26. Unable to hold stimulant or benzodiazepine medication prior to SGB procedure