Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2003
Comparative StudyThe comparative effects of prostaglandin E1 and nicardipine on cerebral microcirculation in rabbits.
We compared the effects of the systemic hypotensive drugs prostaglandin E1 (PGE1) and nicardipine on the cerebral microcirculation and on the cerebrovascular reactivities to hypercapnia and hypoxia. In isoflurane-anesthetized rabbits (n = 48), we measured cerebral pial vessel diameters using a cranial-window preparation: (a) during IV PGE1- or nicardipine-induced mild or moderate hypotension (to 80% or 60% of initial mean arterial blood pressure), (b) after topical administration of these drugs, and (c) during hypercapnia or hypoxia induced during such mild or moderate hypotension. Pial arteriolar diameters were (a) unchanged when hypotension (mild or moderate) was induced by PGE1 but increased when it was induced by nicardipine and (b) increased dose-dependently by topical administration of nicardipine but not PGE1. Only small changes in cerebral venular diameter were observed in these experiments. The pial arteriolar dilator response to hypercapnia was potentiated during hypotension (mild or moderate) when it was induced by PGE1 but decreased when it was induced by nicardipine, whereas the response to hypoxia was maintained during PGE1-induced hypotension but decreased during nicardipine-induced hypotension. In conclusion, as a systemic hypotensive drug, PGE1 does not dilate cerebral arterioles and maintains cerebrovascular reactivities to hypercapnia and hypoxia, whereas nicardipine dilates such vessels and reduces these cerebrovascular reactivities. ⋯ When given systemically to produce mild or moderate hypotension, prostaglandin E1 does not induce cerebral vasodilation and maintains cerebrovascular reactivity to hypercapnia and hypoxia, whereas nicardipine dilates cerebral vessels and reduces both reactivities.
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Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Comparative Study Clinical TrialIntrathecal clonidine added to a bupivacaine-morphine spinal anesthetic improves postoperative analgesia for total knee arthroplasty.
Postoperative pain after total knee arthroplasty (TKA) is severe and can complicate early physical therapy. We tested the hypothesis that intrathecal clonidine would improve postoperative analgesia for TKA using a hyperbaric bupivacaine spinal anesthetic. In a double-blinded, placebo-controlled protocol, 81 ASA physical status I-III patients undergoing either a single or bilateral TKA were randomized into 4 groups with the following 2-mL solutions added to 15 mg of hyperbaric bupivacaine: 1) sterile saline, 2) morphine (250 microg), 3) morphine (250 microg) with clonidine (25 microg), and 4) morphine (250 microg) with clonidine (75 microg). At 1, 2, 4, 6, 12, and 24 h postoperatively, we measured visual analog scales (VAS), cumulative IV morphine consumption, hemodynamics, nausea, ancillary drugs, and side effects. Our primary comparison was between the clonidine with morphine groups versus the morphine group. We found that the combined administration of intrathecal clonidine and morphine decreased 24 h IV morphine consumption by 13 mg (P = 0.028) when compared with intrathecal morphine alone. This corresponded to a decrease in the VAS score of 1.3 cm at 24 h postoperatively (P = 0.047). Adverse side effects were similar among all groups with the exception of more relative hypotension in the clonidine groups through postoperative hour 6. We conclude that the coadministration of intrathecal clonidine and morphine decreases the 24-h IV morphine consumption and improves the 24-h VAS score when compared with intrathecal morphine alone. ⋯ In this prospective, randomized, double-blinded, and placebo-controlled trial, we identify an effective postoperative analgesic approach in total knee replacement surgery. Intrathecal morphine (250 microg) combined with clonidine (25 or 75 microg) provided superior analgesia compared with intrathecal morphine alone.
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Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Clinical TrialGinger does not prevent postoperative nausea and vomiting after laparoscopic surgery.
The potential antiemetic effect of two different oral doses of the herbal remedy ginger (Zingiber officinale) to prevent postoperative nausea and vomiting in 180 patients undergoing gynecologic laparoscopy was investigated in this randomized, double-blinded trial. Ginger failed to reduce the incidence of postoperative nausea and vomiting after these procedures.
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Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Comparative Study Clinical TrialTreating intraoperative hyperchloremic acidosis with sodium bicarbonate or tris-hydroxymethyl aminomethane: a randomized prospective study.
In this study, we evaluated the action of two buffer solutions on acid-base equilibrium in cases of hyperchloremic acidosis. Twenty-four patients undergoing major gynecological intraabdominal surgery received 40 mL. kg(-1). h(-1) of 0.9% saline per protocol. During surgery, in every patient, hyperchloremic acidosis occurred. At a standard base excess of -7 mmol/L, the patients were randomly assigned to receive within 20 min either a mean of 130 +/- 26 mmol of sodium bicarbonate (BIC, 1 M; n = 12) or a mean of 128 +/- 18 mmol of tris-hydroxymethyl aminomethane (THAM, 3 M; n = 12). PaCO(2), pH, serum bicarbonate concentration, standard base excess, and serum concentrations of sodium, potassium, chloride, lactate, phosphate, total protein, and albumin were determined before and 0, 10, and 20 min after buffering. The apparent strong ion difference was calculated as: serum sodium plus serum potassium minus serum chloride minus serum lactate. The effective strong ion difference and the amount of weak plasma acid were calculated by using a computer program. Immediately after buffering, standard base excess increased by 9.8 mmol/L in the BIC group and by 7.2 mmol/L in the THAM group. In both groups, PaCO(2) and the amount of weak plasma acid remained constant. Mainly because of hypernatremia, the apparent and effective strong ion difference increased in the BIC group by 8.5 and 7.9 mEq/L, respectively. In the THAM group, the apparent strong ion difference remained constant; however, the effective strong ion difference increased by 6.4 mEq/L and the anion gap decreased by 5.8 mmol/L because of the occurrence of an unmeasured cation. In conclusion, in case of buffering with BIC or THAM, the changes in pH were accompanied by, and probably caused by, an increase in strong ion difference. ⋯ By comparing two groups of patients with intraoperative hyperchloremic acidosis receiving equal doses of either sodium bicarbonate or tris-hydroxymethyl aminomethane, we assessed the action of both drugs on acid-base equilibrium. In case of "buffering," the changes in pH were accompanied by, and probably caused by, an increase in strong ion difference.
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Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Clinical TrialSuprascapular nerve block prolongs analgesia after nonarthroscopic shoulder surgery but does not improve outcome.
Suprascapular nerve block (SSNB) reportedly improves analgesia and 24-h outcomes after arthroscopic shoulder surgery performed under general anesthesia. In this study, we assessed the analgesic and clinical outcome efficacy of SSNB as an adjunct to interscalene brachial plexus block (ISB) for ambulatory nonarthroscopic shoulder surgery. Fifty patients were randomized to receive either a SSNB or sham injection as part of a standardized ISB-general anesthesia regimen. Time to first significant pain (the primary outcome measure) was significantly delayed in the SSNB group (594 +/- 369 min versus 375 +/- 273 min, respectively; P = 0.02). There were no other differences between groups with regard to postanesthesia recovery unit measures, 24-h assessment of pain, supplemental analgesic use, or quality of life outcomes. We conclude that adjunctive SSNB adds minimal value to a primary ISB anesthetic for nonarthroscopic shoulder surgery. ⋯ When used as an adjunct to an interscalene block combined with general anesthesia, suprascapular nerve block with bupivacaine moderately prolongs analgesia without improving other outcome measures after ambulatory nonarthroscopic shoulder surgery.