Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2003
Randomized Controlled Trial Comparative Study Clinical TrialThe effect of cerebral monitoring on recovery after general anesthesia: a comparison of the auditory evoked potential and bispectral index devices with standard clinical practice.
The use of cerebral monitoring may improve the ability of anesthesiologists to titrate anesthetic drugs. However, there is controversy regarding the impact of the alleged anesthetic-sparing effects of cerebral monitoring on the recovery process and patient outcome. We designed this prospective double-blinded, sham-controlled study to evaluate the impact of intraoperative monitoring with the electroencephalogram bispectral index (BIS) or auditory evoked potential (AEP) device on the usage of desflurane and the time to discharge from the recovery room, as well as on patient satisfaction with their anesthetic experience and recovery. Ninety healthy patients undergoing laparoscopic general surgery procedures using a standardized anesthetic technique were randomly assigned to one of three monitoring groups: standard clinical practice (control), BIS-guided, or AEP-guided. Both the BIS and AEP monitors were connected to all patients before induction of general anesthesia. In the control group, the anesthesiologists were not permitted to observe the BIS or AEP index values during the intraoperative period. In the BIS-guided group, the volatile anesthetic was titrated to maintain a BIS value in the range of 45-55. In the AEP-guided group, the targeted AEP index range was 15-20. The BIS and AEP indices, as well as end-tidal desflurane concentration, were recorded at 3-5 min intervals. Recovery times to awakening, tracheal extubation, fast-track score >or=12, and postanesthesia care unit (PACU) discharge criteria were recorded at 1-10 min intervals. In addition, patient satisfaction with anesthesia and quality of recovery were evaluated on 100- and 18-point scales, respectively, at 24 h after surgery. The AEP- and BIS-guided groups were administered significantly smaller average end-tidal desflurane concentrations than the control group (3.8 +/- 0.9 and 3.9 +/- 0.6 versus 4.7 +/- 1.7, respectively) (P < 0.01). Although the emergence times to eye opening, tracheal extubation, and obeying commands were consistently shorter in the AEP and BIS groups (6 +/- 4 and 6 +/- 5 versus 8 +/- 8 min; 6 +/- 5 and 6 +/- 4 versus 11 +/- 10 min; and 8 +/- 4 and 7 +/- 4 versus 12 +/- 9 min, respectively), only the extubation times were significantly different from the control group (P < 0.05). More importantly, the length of the PACU stay was significantly shorter in both the AEP- and BIS-guided groups (79 +/- 43 and 80 +/- 47 versus 108 +/- 58 min, respectively) (P < 0.05). The patients' quality of recovery was also significantly higher in the two monitored groups (15 +/- 2 versus 13 +/- 3 in the control group, P < 0.05). We concluded that cerebral monitoring with either the BIS or AEP devices reduced the maintenance anesthetic (desflurane) requirement, resulting in a shorter length of stay in the PACU and improved quality of recovery after laparoscopic surgery. However, there were no significant outcome differences between the two cerebral monitored groups. ⋯ Compared with standard monitoring practices, use of an auditory evoked potential or bispectral index monitor to titrate the volatile anesthetic led to a significant reduction in the anesthetic requirement. The anesthetic-sparing effect of cerebral monitoring resulted in a shorter postanesthesia care unit stay and improved quality of recovery from the patient's perspective.
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Anesthesia and analgesia · Dec 2003
Randomized Controlled Trial Comparative Study Clinical TrialThe effect of antiemetics on pupillary reflex dilation during epidural/general anesthesia.
The effect of dopamine D2 receptor antagonists, such as chlorpromazine and haloperidol, on pupil size in awake subjects suggests that these drugs might also alter pupillary reflex dilation and pupil size during general anesthesia. Forty-seven patients undergoing lower abdominal surgery under combined epidural/general anesthesia were randomized to receive one of the 5 following open labeled drugs: 10 mL saline, 0.13 mg/kg ondansetron, 0.25 mg/kg metoclopramide, 0.5 mg/kg metoclopramide, or 0.02 mg/kg droperidol. Three measurements of reflex dilation were taken at 5-min intervals and after the last measurement (time 0) the drug was administered. Measurements were then taken 5, 10, 20, and 40 min after I.V. drug administration. Reflex dilation was induced by intermittent noxious stimulation of the C5 dermatome with a tetanic electric current (60-70 mamp, 100 Hz, 3-s duration) after a stable level of epidural analgesia had been established with 3/8% bupivacaine and maintained with a continuous infusion. Metoclopramide produced a small decrease in pupil diameter and transiently depressed reflex dilation, whereas droperidol decreased pupil size at 10 min and depressed reflex dilation throughout the 40-min study period. Maximal change in reflex dilation was -6.6 +/- 3.3 mm-sec after droperidol. Ondansetron had no effect on pupil diameter or reflex dilation. When pupillary diameter measurements are used to gauge opioid levels during experimental conditions or during surgical anesthesia, antiemetic medication acting on the dopamine D2 receptor should be avoided. ⋯ Miosis is often considered an effect of opioid administration during general anesthesia, but other drugs, such as antiemetics, might produce a similar effect on the pupil. This study demonstrates that 2 antiemetics, droperidol and metoclopramide, constrict the pupil and block the pupillary dilation brought about by nociceptive stimuli.
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Anesthesia and analgesia · Dec 2003
Randomized Controlled Trial Comparative Study Clinical TrialPatient-controlled epidural analgesia versus continuous epidural infusion with ropivacaine for postoperative analgesia in children.
Epidural ropivacaine infusion has been used in children; however, patient-controlled epidural analgesia (PCEA) has not been evaluated in the pediatric population. In this study, we compared the clinical efficiency of PCEA and of continuous epidural infusion analgesia (CEA) in children. Forty-eight children undergoing orthopedic surgery were randomized to receive PCEA or CEA with ropivacaine 0.2%. All patients underwent a standard general anesthetic. Children also received ketoprofen and propacetamol. Pain scores and side effects were recorded for 48 h. If the visual analog score scale score was >4 of 10, analgesia was considered inadequate, and rescue treatment was administered. Both groups obtained effective pain relief. Children in the PCEA group received significantly less local anesthetic than those in the CEA group (0.20 +/- 0.08 mg x kg(-1) x h(-1) versus 0.40 +/- 0.08 mg x kg(-1) x h(-1); P < 0.001). Motor effects, supplemental analgesic requirements, and side effects did not differ. We concluded that PCEA with ropivacaine 0.2% can provide adequate postoperative analgesia for pediatric orthopedic procedures with smaller dose requirements than CEA. ⋯ We studied patient-controlled epidural analgesia (PCEA) and continuous epidural infusion analgesia (CEA) with 0.2% ropivacaine during the postoperative period in children. We found that either PCEA or CEA with plain ropivacaine 0.2% provided adequate pain relief in children during the first 48-h postoperative course. However, adequate analgesia was obtained with 50% less volume infused with PCEA compared with CEA.
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Anesthesia and analgesia · Dec 2003
ReviewKetamine in chronic pain management: an evidence-based review.
Ketamine has diverse effects that may be of relevance to chronic pain including: N-methyl-D-aspartic acid, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, kainate, gamma-aminobutyric acid(A) receptors; inhibition of voltage gated Na(+) and K(+) channels and serotonin, dopamine re-uptake. Ketamine has been in clinical practice for over 30 yr; however, there has been little formal research on the effectiveness of ketamine for chronic pain management. In this review we evaluate the available clinical data as a basis for defining the potential use of ketamine for chronic pain. ⋯ In conclusion, the evidence for efficacy of ketamine for treatment of chronic pain is moderate to weak. However, in situations where standard analgesic options have failed ketamine is a reasonable "third line" option. Further controlled studies are needed.
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Anesthesia and analgesia · Dec 2003
Randomized Controlled Trial Clinical TrialPreoperative interscalene block for elective shoulder surgery: loss of benefit over early postoperative block after patient discharge to home.
We performed a randomized, prospective, parallel-group, open-label, multicenter trial to compare the effects of pre- versus postoperative interscalene block using levobupivacaine on postoperative pain and analgesic requirements. One-hundred-two outpatients scheduled for elective shoulder surgery were randomized to receive 30 mL of 0.5% levobupivacaine either preoperatively (PRE group) or postoperatively (POST group). Analgesic outcome measures during the postoperative period were: (a). time to first request for analgesic medication after surgery, (b). pain intensity using the visual analog scale at rest and during arm movement, and (c). total analgesic consumption of nonsteroidal antiinflammatory drugs and opioids. The time to first analgesic request did not differ between treatment groups. However, mean maximum pain intensity scores during the day of surgery were significantly less for the PRE group than the POST group, both at rest (P = 0.001) and after movement (P = 0.004). The mean opioid administered during surgery was lower in the PRE than the POST group (P < 0.001). Levobupivacaine was well tolerated in both treatment groups, and no adverse reactions were related to this local anesthetic. In conclusion, preoperative interscalene block with levobupivacaine provided superior pain control for the first 12 h after surgery, but this benefit was not maintained during the week after discharge because the subjects assumed control of their own pain relief as outpatients. ⋯ Preoperative interscalene block with levobupivacaine provides safe and effective analgesia for same-day elective shoulder surgery, but the benefit of this one-time intervention does not persist.