Hydromorphone Pharmacokinetic-Pharmacodynamic Fingerprint

After 6 h of fasting, each volunteer will have a 20G arterial-line placed in the radial artery for early blood sampling and an 18 G peripheral intravenous catheter placed in the contralateral forearm for drug administration and later blood sampling. Continuously monitored vital signs will include ECG, invasive blood pressure, hemoglobin, O2 saturation, end-tidal CO2, and respiratory rate (from the capnogram) recorded. After baseline PD data acquisition, a bolus of 0.2 mg/kg hydromorphone will be administered over 10 sec via the free-flowing peripheral IV (t=0) and 3 mL arterial blood samples will be obtained at 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75, and 2 min using a stop-cock and manifold system. Subsequent blood samples will be acquired at 3, 4, 5, 7.5, 10, 15, 20, 25, 30, and 45 min and 1, 1.25, 1.5, 2, 2.25, 2.5, 2.75, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 10, 12, 16, 20, and 24 h. Although EEG will be acquired continuously, the remaining pharmacologic data will be recorded at discrete times s in the initial 5 min: pupillometry at 1, 2, and 5 min; ventilation at 2 min; temperature analgesia at 3 and 5 min, and sedation level at 4 min. This will allow the ventilation and pupillometry to be acquired in a resting state, thereby limiting distortion of these responses by stimulation. Subsequently, all data will be acquired at all PK time points in the following sequence - ventilation and EEG (simultaneously), pupillometry, modified OAA/S score, and temperature analgesia. After 2 h, once a pharmacologic parameter has returned to baseline for 2 sequential measurements, recording of that parameter will be stopped. During the study, if the volunteer is unable to use the device trigger, due to opioid-induced sedation, the tolerance level for increased temperature will be defined as the temperature at which the volunteer exhibits withdrawal movement of the tested limb. Once all data acquisition has been completed, the volunteer will be allowed to drink clear liquids. Subsequently, the diet will be advanced as tolerated. The volunteer will be monitored hourly (vital signs) in the Clinical Research Unit until all of the blood samples have been acquired.