No abstract

Objective: To evaluate the effectiveness of propofol and fentanyl when used by emergency physicians (EPs) for systemic sedation and analgesia in the ED. Methods:Over an eight-month period, a convenience sample of consenting patients at an urban teaching hospital ED who required sedation for painful procedures were enrolled in a descriptive study of therapeutic propofol sedation. After receiving 2 pgkg of fentanyl IV, the patients received a continuous infusion of propofol at 0.21 mg/kg/min IV to the desired level of sedation. A maintenance infusion of 3-6 mg/kg/hr was administered during the remainder of the procedure. Sedation time, total procedure time, and recovery time were recorded and the presence of side effects was noted. The patients and the physicians rated their satisfaction with the technique on a 100-mm visual analog scale. The patients were contacted at 24 hours for follow-up information.Results: Twenty patients (aged 19-62 years) received propofol infusion for procedures that included ten abscess incision and drainages, eight orthopedic reductions, one chest tube placement, and one wound exploration. The mean (+SD) total dose of propofol was 200 & 160 mg. The mean time to onset of sedation was 6.6 2 3.2 min, the mean procedure interval was 9.6 2 6.3 min, and the mean interval until recovery was 6.1 2 4.1 min. The median patient satisfaction score was 97 mm (range 40-100 mm); the median rating by physicians was 88 mm (range 4-100 mm). Side effects were noted in six patients: three had pain on injection, one had pain on injection and brief ( 4 min) hypotension (systolic blood pressure = 80 mm Hg), and two had apnea (<30 sec). Seven patients had some recall of the procedure immediately afterwards, but only five had any recall at 24 hours. All 20 patients stated they would be willing to receive the same sedation again for a future procedure.Conclusion: Propofol appears to be an effective agent to provide systemic sedation and analgesia when used in conjunction with fentanyl for procedures in the ED. Given its rapidity of onset and elimination, it may become a useful agent to EPs for IV sedation in the ED.

No abstract

Reconnaissance mapping along Copper Canyon highway has established ignimbrite stratigraphic relationships over a relatively large area in the central part of the Sierra Madre Occidental volcanic fi eld in western Chihuahua, Mexico. The oldest ignimbrites are found in the central part of the area, and they include units previously mapped from north of the study area, in and around the Tomóchic volcanic complex. Copper Canyon, at the southern end of the study area, exposes younger units, including the intracaldera tuff of the Copper Canyon caldera and fi ve overlying ignimbrites. Well-exposed calderas are found near San Juanito, in the central part of the map area, and at Sierra Manzanita, to the far north. Stratigraphic evidence for yet another caldera in the northern part of the area is found in the Sierra El Comanche. The stratigraphic and limited available isotopic age data suggest that volcanism was particularly active ~30 m.y. ago. This reconnaissance survey also documented lava-fl ow lithologies consistent with previous observations from Tomóchic that intermediate lavas have erupted throughout that area's volcanic history and that basaltic andesite became particularly abundant as felsic volcanism waned. The combined Copper Canyon-Tomóchic area gives the fi rst view into the core of the giant Sierra Madre Occidental volcanic fi eld, expanding that offered by earlier reports, mostly from peripheral regions. The emerging picture is one of a dramatically thickened and stratigraphically complex volcanic section related to numerous overlapping caldera complexes, much like that documented for the core of the San Juan Mountains volcanic fi eld, Colorado.