Anesthesia and analgesia
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Anesthesia and analgesia · Nov 2001
Randomized Controlled Trial Comparative Study Clinical TrialInduction of anesthesia in the elderly ambulatory patient: a double-blinded comparison of propofol and sevoflurane.
Hypotension during induction of anesthesia is common and particularly undesirable in elderly patients. This study has shown that inhaled induction with sevoflurane is well tolerated by the elderly and is associated with higher mean arterial pressure than slow propofol induction.
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Anesthesia and analgesia · Nov 2001
Randomized Controlled Trial Clinical TrialEpinephrine does not prolong the analgesia of 20 mL ropivacaine 0.5% or 0.2% in a femoral three-in-one block.
We tested the effect of epinephrine added to 20 mL ropivacaine 0.5% and 0.2% on postoperative analgesia via a femoral catheter after total knee replacement. Forty-one patients undergoing total knee replacement under combined peripheral block/general anesthesia were randomly allocated to two groups. After insertion of a femoral catheter, 21 patients in the Ropivacaine-Epinephrine (ROPI-EPI) group received 20 mL ropivacaine 0.5% plus epinephrine 1:200,000, whereas 20 patients in the Ropivacaine group (ROPI) received 20 mL plain ropivacaine 0.5%. Thereafter, a sciatic block with 30 mL bupivacaine 0.5% plus epinephrine 1:200,000 was performed in all patients, followed by general anesthesia. After surgery, patient-controlled analgesia (PCA) with ropivacaine 0.2% plus epinephrine 1:200,000 for Group ROPI-EPI and plain ropivacaine 0.2% for Group ROPI was available via the femoral catheter (200 mL ropivacaine 0.2% +/- epinephrine, bolus 20 mL, lockout 120 min). The patients were instructed to use PCA when the knee pain score was >3 cm. The interval between the initial ropivacaine injection and the first PCA injection determined the duration of 20 mL ropivacaine 0.5% +/- epinephrine, whereas the interval between the first and second PCA injection determined the duration of 20 mL ropivacaine 0.2% +/- epinephrine. The average duration of ropivacaine 0.5% was 657 +/- 345 min for the ROPI-EPI group and 718 +/- 423 min for the ROPI group (NS), whereas for ropivacaine 0.2%, the average duration was 409 +/- 245 min for the ROPI-EPI group and 419 +/- 339 min for the ROPI group (not significant). We conclude that epinephrine does not influence the duration of analgesia of the ropivacaine concentrations investigated. ⋯ We evaluated the effect of epinephrine on the duration of analgesia of 20 mL ropivacaine 0.5% or 0.2% injected in femoral three-in-one block for pain relief after total knee replacement. Our results show that epinephrine does not alter the duration of analgesia of the two solutions investigated.
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Anesthesia and analgesia · Nov 2001
Randomized Controlled Trial Multicenter Study Clinical TrialThe pharmacokinetics of remifentanil in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass.
Remifentanil is a potent opioid with a short duration of action. It has the potential for large-dose opioid anesthesia without an obligatory prolonged period of mechanical ventilation. However, because of high clearance and rapid tissue distribution, cardiopulmonary bypass (CPB) may influence its pharmacokinetics and alter drug requirements. We administered remifentanil by continuous infusion to 68 patients having coronary artery bypass graft surgery during CPB with hypothermia to describe the effects of these interventions on its pharmacokinetics. Remifentanil concentrations were measured before, during, and after CPB. Disposition was best described by a two-compartment model. The volume of distribution increased by 86% with institution of CPB and remained increased after CPB. Elimination clearance decreased by 6.37% for each degree Celsius decrease from 37 degrees C. ⋯ Remifentanil concentrations decrease with the institution of cardiopulmonary bypass because of an increase in the volume of distribution. The decrease in elimination clearance with hypothermia results in increased total remifentanil concentrations during cardiopulmonary bypass if the infusion rate is not altered. More constant blood remifentanil levels may be obtained by reducing remifentanil infusion rate by 30% for each 5 degrees C decrease in temperature.
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Anesthesia and analgesia · Nov 2001
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of tramadol, amitriptyline, and meperidine for postepidural anesthetic shivering in parturients.
Tramadol is effective for treating shivering during epidural anesthesia in parturients. In addition to its low affinity to opioid receptors, tramadol exerts a modulatory effect on central monoaminergic pathways. In this respect, there are parallels between the mechanisms of the action of tramadol and antidepressants such as amitriptyline. Meperidine is often recommended for the treatment of postanesthetic shivering. This prospective, double-blinded, and randomized clinical study was performed to compare the antishivering effects and accompanying side effects among tramadol, meperidine, and amitriptyline for the treatment of postepidural anesthetic shivering. Forty-five parturients who shivered during cesarean delivery under epidural anesthesia and requested antishivering treatment were randomly allocated to one of three groups for IV treatment: Group T (n = 15) received tramadol 0.5 mg/kg, Group M (n = 15) received meperidine 0.5 mg/kg, and Group A (n = 15) received amitriptyline 15 or 20 mg. The response rate (shivering ceased after treatment in 15 min) was 87% and 93% for Groups T and M, respectively, compared with 13% in Group A (P < 0.01). The time that elapsed from treatment to the time shivering ceased was 5.1 +/- 3.6 min (mean +/- SD) for Group T and 4.2 +/- 2.3 min for Group M. There was a significantly more frequent incidence (33%) of somnolence in Group M when compared with Groups T (7%) and A (0%) (P < 0.01). However, no significant differences were shown for pruritus, nausea, vomiting, or Apgar scores of newborns. We concluded that both tramadol and meperidine show a significantly faster response rate in the treatment of postepidural anesthetic shivering when compared with amitriptyline in the dosage used; tramadol had a decreased incidence of somnolence when compared with meperidine. ⋯ This study was performed to compare the antishivering and side effects among tramadol, amitriptyline, and meperidine for the treatment of postepidural anesthetic shivering in parturients. Both tramadol and meperidine show a significantly faster response rate in the treatment of shivering when compared with amitriptyline. Tramadol had a less frequent incidence of somnolence than meperidine.
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Anesthesia and analgesia · Nov 2001
Randomized Controlled Trial Clinical TrialA carbohydrate-rich drink reduces preoperative discomfort in elective surgery patients.
We studied the effects of different preoperative oral fluid protocols on preoperative discomfort, residual gastric fluid volumes, and gastric acidity. Two-hundred-fifty-two elective abdominal surgery patients (ASA physical status I-II) were randomized to preparation with a 12.5% carbohydrate drink (CHO), placebo (flavored water), or overnight fasting. The CHO and Placebo groups were double-blinded and were given 800 mL to drink on the evening before and 400 mL on the morning of surgery. Visual analog scales were used to score 11 different discomfort variables. CHO did not increase gastric fluid volumes or affect acidity, and there were no adverse events. The visual analog scale scores in a control situation were not different between groups. During the waiting period before surgery, the CHO-treated group was less hungry and less anxious than both the other groups (P < or = 0.05). CHO reduced thirst as effectively as placebo (P < 0.0001 versus Fasted). Trend analysis showed consistently decreasing thirst, hunger, anxiety, malaise, and unfitness in the CHO group (P < 0.05). The Placebo group experienced decreasing unfitness and malaise, whereas nausea, tiredness, and inability to concentrate increased (P < 0.05). In the Fasted group, hunger, thirst, tiredness, weakness, and inability to concentrate increased (P < 0.05). In conclusion, CHO significantly reduces preoperative discomfort without adversely affecting gastric contents. ⋯ Discomfort during the period of waiting before elective surgery can be reduced if patients are prepared with a carbohydrate-rich drink, compared with preoperative oral intake of water or overnight fasting. Visual analog scales can provide useful information about preoperative discomfort in elective surgery patients.