Effect of an opioid management program for Colorado workers' compensation providers on adherence to treatment guidelines for chronic pain.

OBJECTIVE: The aim of this study was to examine adherence of state guidelines for Colorado workers' compensation physicians/providers treating individuals as injured workers with chronic pain after initiation of an opioid management program and provider incentives. METHODS: A retrospective cohort of chronic, non-cancer pain claims was constructed from the Colorado's workers' compensation database. Adherence to treatment guidelines and opioid prescribing practices were evaluated during implementation of a new billing code to incentivize adherence. RESULTS: Overall, less than 33% of claims showed evidence of opioid management. Comprehensive opioid management was observed in only 4.4% of claims. In 2010, after implementing the new billing code, the ratio of long acting opioids to short acting opioids decreased from 0.2 to 0.13; returning to 0.2 in one year. Similarly, morphine equivalent doses declined for a short period. CONCLUSIONS: Incentivizing physicians to adhere to chronic pain management guidelines only temporarily improves prescribing practices.

Prostaglandin E2 EP1 receptor inhibition fails to provide neuroprotection in surgically induced brain-injured mice.

Recent trials have shown that the prostaglandin E2 EP1 receptor is responsible for NMDA excitotoxicity in the brain after injury. Consequently, in this study, we investigated the use of SC-51089, a selective prostaglandin E2 EP1 receptor antagonist, as a pre-treatment modality to decrease cell death, reduce brain edema, and improve neurobehavioral function after surgically induced brain injury (SBI) in mice. Eleven-week-old C57 black mice (n=82) were randomly assigned to four groups: sham (n=31), SBI (n=27), SBI treated with SC51089 at 10 µg/kg (n=7), and SBI treated with SC51089 at 100 µg/kg (n=17). Treated groups received a single dose of SC51089 intrapertioneally at 12 and 1 h pre-surgery. SBI was performed by resecting the right frontal lobe using a frontal craniotomy. Postoperative assessment occurred at 24 and 72 h, and included neurobehavioral testing and measurement of brain water content and cell death. Results indicated that neither low- nor high-dose EP1 receptor inhibition protected against the SBI-related effects on brain edema formation or cell death. There was however a significant improvement in neurobehavioral function 24 h post-SBI with both dosing regimens. Further studies will be needed to assess the potential therapeutic role of EP1 receptor targeting in SBI.

Hyperbaric oxygen preconditioning reduces postoperative brain edema and improves neurological outcomes after surgical brain injury.

The present study was designed to examine if hyperbaric oxygen preconditioning (HBO-PC) is neuroprotective in a mouse model of surgical brain injury (SBI). C57BL mice were administered 100% oxygen for 1 h at 2.5 ATA for 5 consecutive days and subjected to SBI on the following day. The HBO-PC + SBI animals were compared to sham and normoxia + SBI groups for brain water content in different brain regions at 24 and 72 h after surgery. Blood-brain barrier (BBB) permeability was evaluated using Evan's blue dye extravasation at 24 h. Neurological assessment of the animals was done by a blinded observer at 24 and 72 h. The results showed that brain water content was significantly increased in the right (ipsilateral) frontal lobe surrounding the site of resection. This was attenuated by HBO-PC at 24 and 72 h. However, HBO-PC did not have any effect on the increased BBB permeability observed after SBI. Significant neurological deficits were observed after SBI. HBO-PC improved neurological deficits at 72 h on the 21-point sensorimotor scale and at 24 and 72 h on the wire hang and beam balance scoring. In conclusion, HBO-PC attenuates post-operative brain edema and improves neurological outcomes following SBI.

Cyclo-oxygenase-2 mediates hyperbaric oxygen preconditioning-induced neuroprotection in the mouse model of surgical brain injury.

BACKGROUND AND PURPOSE: We investigated the role of cyclo-oxygenase-2 (COX-2) in mechanisms of hyperbaric oxygen preconditioning (HBO-PC) in the mouse model of surgical brain injury (SBI). METHODS: C57BL mice were administered 100% oxygen for 1 hour at 2.5 atmosphere absolute for 5 consecutive days and subjected to SBI. Neurological status and brain edema were evaluated at 24 hours and 72 hours after the brain insult. Fluorescent immunostaining and Western blotting were performed to study hypoxia-inducible factor-1alpha and COX-2, respectively. Two doses of COX-2 inhibitor, NS398 (3 mg/kg and 10 mg/kg) were used to verify the role of COX-2 signaling pathway in the mechanism of HBO-PC. RESULTS: HBO-PC improved neurological status and decreased brain edema at 24 hours and 72 hours after SBI. HBO-PC by itself and SBI independently increased COX-2 levels by 2-fold and 4-fold, respectively. HBO-PC, however, reduced increase in hypoxia-inducible factor-1alpha and COX-2 expression after SBI. The HBO-PC-induced improvement in neurological status and brain edema was reversed by a suboptimal dose of the COX-2 inhibitor, NS398 (10 mg/kg intraperitoneally; 1/4th of dose shown to provide neuroprotection), which itself had no effect on investigated end points. CONCLUSIONS: HBO-PC attenuates postoperative brain edema and improves neurological outcomes after SBI. The HBO-PC-induced neuroprotection is mediated through COX-2 signaling pathways.