Reinstituting the Bolus - New Reasoning for an Existing Technique.

Improved intrathecal (IT) pump technology is increasing the accuracy of IT opioid bolus dosing and promising advances in pain therapy. Opioid bolus dosing can be used with a minimal continuous infusion or it can function as the sole therapy. Bolus-only dosing is characterized by minimal use of opioid (often less than 1 mg of IT morphine). It achieves adequate pain control while reducing tolerance and possibly opioid-induced hyperalgesia. It may prevent receptor saturation, and provide a "washing out" of the opioid receptor that prevents the observed dose escalation resulting from continuous infusions. With new bolus dosing possibilities, IT pumps can be used earlier in the treatment algorithm instead of being a late-stage treatment for patients who responded poorly to conservative treatments. We hypothesize that morphine bolus-only IT dosing will have comparable adverse effect rates, and possibly increased safety as compared to the more conservative continuous delivery method. We further predict that bolus-only delivery will provide better therapy satisfaction, improved functional scores, lower 24 hour opioid dose, and less dose escalation.