Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2004
Clinical TrialContinuous assessment of cerebral autoregulation in subarachnoid hemorrhage.
Cerebral vasospasm remains a leading cause of morbidity and mortality after subarachnoid hemorrhage (SAH). Cerebral ischemia may ensue when autoregulation fails to compensate for spasm. We examined how autoregulation is affected by vasospasm by using transcranial Doppler. The moving correlation coefficient between slow changes of arterial blood pressure and mean or systolic flow velocity (FV), termed "Mx" and "Sx," respectively, was used to characterize cerebral autoregulation. Vasospasm was declared when the mean FV increased to more than 120 cm/s and the Lindegaard ratio was more than 3. This occurred in 15 of 32 SAH patients. On the basis of the bilateral transcranial Doppler recordings of the middle cerebral artery in vasospastic patients, Mx and Sx were calculated for baseline and vasospasm. Mx increased during vasospasm (0.46 +/- 0.32; mean +/- SD) and was significantly higher (P = 0.021) than at baseline (0.21 +/- 0.24). Sx was also increased (0.22 +/- 0.26 vs 0.05 +/- 0.21 at baseline; P = 0.03). Mx correlated with mean FV (r = 0.577; P = 0.025) and the Lindegaard ratio (r = 0.672; P < 0.006). Mx (P = 0.006) and Sx (P = 0.044) were higher on the vasospastic side (Mx, 0.44 +/- 0.27; Sx, 0.24 +/- 0.23) when compared with the contralateral side (Mx, 0.34 +/- 0.29; Sx, 0.16 +/- 0.25). The increased Mx and Sx during cerebral vasospasm demonstrate impaired cerebral autoregulation. Mx and Sx provide additional information on changes in autoregulation in SAH patients. ⋯ The moving correlation coefficients between slow changes of arterial blood pressure and mean or systolic flow velocity, termed "Mx" and "Sx," respectively, characterize cerebral autoregulation but have not been applied to subarachnoid hemorrhage. A study in 15 patients revealed that Mx and Sx were significantly increased, indicating impaired autoregulation during vasospasm as compared with baseline, as well as on the side of vasospasm in comparison with the contralateral side.
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Anesthesia and analgesia · Apr 2004
Randomized Controlled Trial Comparative Study Clinical TrialAnalgesic effects of intraarticular sufentanil and sufentanil plus methylprednisolone after arthroscopic knee surgery.
We studied the effect of intraarticular saline, sufentanil, or sufentanil plus methylprednisolone after knee arthroscopic meniscectomy. In a double-blind randomized study, 60 patients undergoing knee arthroscopic meniscectomy were allocated to groups receiving intraarticular saline, intraarticular sufentanil 10 microg, or sufentanil 10 microg plus methylprednisolone 40 mg at the end of arthroscopy during general anesthesia. Postoperatively, pain levels at rest and during movement (i.e., active flexion of the knee) were measured by a visual analog scale and were significantly decreased in the sufentanil and sufentanil plus methylprednisolone groups compared with the control group. Moreover, we found that there was a significant reduction in intraarticular sufentanil and sufentanil plus methylprednisolone in the postoperative consumption of analgesics. We also found that the use of intraarticular sufentanil or sufentanil plus methylprednisolone after knee arthroscopic meniscectomy decreases the amount of supplementary analgesic needed for pain relief during the early postoperative period. In addition, we detected that sufentanil provided prolonged pain relief up to 24 h when compared with control, whereas when we combined sufentanil plus methylprednisolone, we found that it further reduced pain and use of analgesics when compared with sufentanil. ⋯ The combined use of intraarticular sufentanil (10 microg) and methylprednisolone (40 mg) in arthroscopic meniscectomy surgery reduced both postoperative pain scores and the use of additional analgesics.
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Anesthesia and analgesia · Apr 2004
Intrathecal clonidine and bupivacaine have synergistic analgesia for acute thermally or inflammatory-induced pain in rats.
We investigated the interaction between spinally administered bupivacaine and clonidine using an animal model of acute and inflammatory pain. Rats implanted with lumbar intrathecal catheters were injected intrathecally with saline (control), bupivacaine (1 to 100 microg), or clonidine (0.1 to 3 microg) and tested for their responses to thermal stimulation to the tail (tail flick test) and subcutaneous formalin injection into the hindpaw (formalin test). The effects of the combination of bupivacaine and clonidine on both stimuli were tested by isobolographic analysis. General behavior and motor function were examined as side effects. The 50% effective doses of bupivacaine and clonidine were significantly smaller when combined compared with each single drug in both the tail flick test (2.82 and 0.11 microg versus 7.1 and 0.29 microg, respectively) and phase 1 (0.24 and 0.009 microg versus 5.7 and 0.15 microg) and phase 2 (0.31 and 0.012 microg versus 3.2 and 0.16 microg) of the formalin test. Side effects were decreased by the combination. These results suggest a favorable combination of intrathecal bupivacaine and clonidine in the management of acute and inflammatory pain. ⋯ The analgesic interaction between intrathecally administered bupivacaine and clonidine was examined during acute thermal and inflammatory-induced pain in rats. The analgesia produced by the combination of these two drugs was synergistic in both acute thermal and inflammatory induced pain, with a decrease in behavioral side effects.
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Anesthesia and analgesia · Apr 2004
Comparative StudyThe effects of pretreatment with lidocaine or bupivacaine on the spatial and temporal expression of c-Fos protein in the spinal cord caused by plantar incision in the rat.
We investigated the spatial and temporal patterns of c-Fos protein (Fos) expression in the dorsal horn of the spinal cord caused by plantar incision in the rat and the effects of pretreatment with local anesthetics. Bupivacaine (0.5%), lidocaine (2%), or saline for control was injected for nerve block and local infiltration before the plantar incision was made under anesthesia. Pain behavior and Fos expression in the L4-L5 segments of the spinal cord were assessed at 1, 3, 6, 24, 48, 72, and 120 h after the incision. The withdrawal threshold to mechanical stimulation decreased significantly at 1 h until 120 h (1-72 h, P < 0.01;120 h, P < 0.05), and pretreatment with local anesthetics increased the threshold significantly at 1 h (both groups: P < 0.01), 3 h (both groups: P < 0.01), and 6 h (bupivacaine, P < 0.01; lidocaine, P < 0.05) in comparison with that in the saline group. In the saline group, Fos expression was detected predominantly in laminae I-II and V-VI, and the total Fos expression was maximal at 1 h and then decreased gradually. Pretreatment with local anesthetics suppressed Fos expression significantly in all layers, and this suppression continued for several days. This study provides evidence of spatial and temporal changes in Fos expression induced by plantar incision. Our results indicate that although pretreatment with local anesthetics suppresses Fos expression for several days in the postoperative period, the analgesic effect is observed only for the expected duration of the local anesthetic used. ⋯ Prevention of early pain by pretreatment with local anesthetics provides little benefit for postoperative pain relief in the plantar incision model, although c-Fos expression is suppressed. The number of c-Fos-expressing neurons is not necessarily correlated with pain behavior.
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Anesthesia and analgesia · Apr 2004
Randomized Controlled Trial Clinical TrialPreoperative oral dextromethorphan attenuated tourniquet-induced arterial blood pressure and heart rate increases in knee cruciate ligament reconstruction patients under general anesthesia.
The precise mechanism of tourniquet-induced arterial blood pressure increase is unknown. We determined the effect of preoperative oral dextromethorphan (DM) on arterial blood pressure and heart rate changes during tourniquet inflation in knee cruciate ligament reconstruction patients under general anesthesia. Patients in the DM group (n = 38) received oral DM 30 mg, and patients in the control group (n = 38) received oral placebo 2 h before the induction of anesthesia. Anesthesia was maintained with sevoflurane 2.0% and N(2)O in 33% oxygen, and the trachea was intubated until the end of surgery. Arterial blood pressure and heart rate were measured at 0, 30, and 60 min after the start of tourniquet inflation. Systolic arterial blood pressure and heart rate at 60 min in the control group were significantly more than those in the DM group (131.1 +/- 15.8 mm Hg versus 123.6 +/- 15.9 mm Hg [P < 0.05] and 74.1 +/- 11.3 bpm versus 67.8 +/- 8.5 bpm [P < 0.01], respectively). The percentage increase in systolic arterial blood pressure and heart rate in the DM group was also attenuated when compared with that in the control group (P < 0.05). In conclusion, preoperative oral DM 30 mg significantly attenuated arterial blood pressure and heart rate increases during tourniquet inflation under general anesthesia. ⋯ We demonstrated that preoperative oral dextromethorphan 30 mg significantly attenuated arterial blood pressure and heart rate increases at 60 min during tourniquet inflation in patients undergoing knee cruciate ligament reconstruction under general anesthesia.