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March 1997 Patient-controlled sedation for cataract surgery using peribulbar block.Pac-Soo CK, Deacock S, Lockwood G et al.British Journal of Anaesthesia,1996;77:370-374 [ see abstract below ] Typically, sedation to supplement cataract surgery under peribulbar block is given intravenously by a health care professional. This study investigates patient-controlled sedation in a group of patients with median ages 67-70. Patients were able to administer increments of either midazolam 0.1 mg, propofol 3.3 mg or saline. Patient controlled sedation significantly reduced the level of anxiety as assessed by the patients in all groups, including drugs and placebo. The median total doses were 2.5 mg midazolam and 87 mg propofol. Three patients in the midazolam group feel asleep during surgery but were awakened by verbal communication; one additional patient develop oximetry saturation less than 90% for more than one minute which responded to voluntary deep breathing. One additional patient in a midazolam group became over-sedated and the drug effects were reversed with flumazenil before the block was performed. Cooperation of the patients as assessed by the surgeon was good except for one patient in the placebo group, 3 midazolam patients and one propofol patient. Not all patients used the pump to provide sedation. The over-sedation produced in the midazolam group may have been related to the absence of a lockout interval on the pump. Additional doses of midazolam were therefore administered before prior doses had fully taken effect, a problem exacerbated by the age of this study group. This study demonstrates that elderly patients can provide acceptable self-administered sedation for their cataract surgery, as long as appropriate doses and timing intervals are chosen. Return to the Current Literature Review Front Page, or read the abstract: ABSTRACT Patients undergoing cataract surgery using peribulbar block were allocated randomly to self-administer doses of either midazolam 0.1 mg or propofol 3.3 mg without a lock-out facility; in the control group the syringe was charged with saline, not as a placebo, but to "blind" the surgeon and the nurse observer. For midazolam and propofol, median doses were 2.54 (0.1-6.0) mg and 87.4 (0-145) mg, respectively. Patient-controlled sedation significantly reduced the level of anxiety, with median visual analogue anxiety scores in the midazolam, propofol and saline groups of 5 (0-38) mm, 5 (0-25) mm and 15 (0-92) mm, respectively (P <0.05). Some patients did not administer the sedative when available while others in the saline group would have benefited from anxiolytic drugs. While both drugs prevented an increase in heart rate, only midazolam prevented an increase in arterial pressure during surgery. |
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