High thoracic/low cervical, long-term intrathecal (IT) infusion of bupivacaine alleviates "refractory" pain in patients with unstable angina pectoris: Report of 2 cases

Background : There is no reliable treatment for "refractory" pain from unstable angina pectoris (UAP) when epidural infusion of bupivacaine has failed to relieve it. In two such cases we explored the potential of intrathecal (IT) bupivacaine infusion to provide pain relief.
Patients and methods : Two female patients, 70 and 67 years. An 18-G nylon catheter was inserted intrathecally through a 17-G Tuohy needle via the T2–T3 interspace and its tip located at the height of C6–C7 vertebrae. The catheter was connected to a portable, programmable electronic pump filled with bupivacaine 5 mg/ml. The infusion started at rates of 0.1–0.2 ml/h, with optional bolus doses of 0.1–0.2 ml, 4–2 times/h, respectively, by PCA ( P atient- C ontrolled A nalgesia), and then adjusted to give the patients satisfactory (80%–100%) pain relief.
Results : Pain relief was obtained with doses of IT-bupivacaine ranging from 17 to 45 (mean=25) mg/d. The pain intensity decreased from VAS ( V isual A nalogue S core) 9–10 to 0–2 out of 10. The nocturnal sleep improved from 2–4 to 6–7 h. The patients could now ambulate, walking or in a wheel-chair. The IT-treat-ment lasted 700 and 437 d, of which 540 and 343 d (respectively) were spent at home, and was terminated by: (a) the patient's death due to intracranial bleeding (1st case); (b) progressive aggravation of the unstable angina that could not be fully countered by increasing the bupivacaine dose above 1.0 mg/h due to occurrence of cerebral transient ischemic attacks, usually not correlated with orthostatic arterial hypotension but apparently facilitated by microembolization of the cerebral arteries (2nd case).
Conclusion : IT-bupivacaine infusion may alleviate "refractory" pain in patients with unstable angina pectoris when epidural bupivacaine failed to do so. Its use is apparently limited by the IT-bupivacaine critical dosage (in these patients = 1.0–1.5 mg/h).