Experimental Pain and Opioid Analgesia in Volunteers at High Risk for Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is characterized by recurrent nocturnal hypoxia and sleep disruption, both of which have been shown to impact pain and /or analgesia behavior. Thresholds and tolerances for experimentally induced heat– and cold– related pain, were assessed in volunteers at risk for OSA, at baseline and during an opioid (remifentanil) infusion. Volunteers were also underwent over-night polysomnography and blood draw for determination of inflammatory and hypoxia markers. Mixed linear regression analysis showed that increased serum levels of inflammatory (tumor necrosis factor-a, interleukin-1b) and hypoxia (insulin growth factor binding protein-1) markers were associated with an enhanced sensitivity to the analgesic effect of remifentanil. Statistical model adjustment for the presence of inadequate /fragmented sleep in these subjects, support an independent association of hypoxia and inflammation with opioid analgesic pharmacology. Further studies in larger populations and different settings are required to establish the potential clinical significance of these findings.