Anesthesia and analgesia
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Anesthesia and analgesia · Nov 2002
Randomized Controlled Trial Comparative Study Clinical TrialA randomized, double-blinded trial of subarachnoid bupivacaine and fentanyl, with or without clonidine, for combined spinal/epidural analgesia during labor.
Subarachnoid clonidine may increase the duration of spinal opioid and local anesthetic analgesia during labor, but it may also increase hypotension and sedation, and the therapeutic range is unclear. We studied 110 term parturients of mixed parity having combined spinal/epidural analgesia during labor in this randomized, double-blinded trial. All received subarachnoid fentanyl 20 micro g and bupivacaine 2.5 mg, plus either saline or clonidine (15, 30, or 45 micro g). Of 101 per-protocol parturients (n = 25, 24, 26, and 26 in Groups C0, C15, C30, and C45, respectively), 22 delivered before the cessation of spinal analgesia. Group demographics and pain scores from Time 0 to 120 min were similar. There was no significant difference among groups in the duration of spinal analgesia (P = 0.09) or in the duration of clonidine groups combined compared with control (median, 120 min [interquartile range, 96-139 min] versus 98 min [80-120 min]; P = 0.07). Systolic blood pressure was significantly lower in all clonidine groups between 40 and 90 min (P = 0.001). Hypotension (P = 0.05) and the requirement for ephedrine (P = 0.02) were dose dependent, but groups had a similar incidence of hypotension. The addition of clonidine 15-45 micro g to subarachnoid fentanyl and bupivacaine reduced blood pressure and did not significantly increase the duration of spinal analgesia. ⋯ The addition of 15-45 micro g of clonidine to subarachnoid fentanyl plus bupivacaine did not significantly increase the duration of spinal analgesia but did decrease maternal blood pressure. The results of this study do not support the use of subarachnoid clonidine to prolong the action of spinal labor analgesia when fentanyl plus bupivacaine are administered.
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Anesthesia and analgesia · Nov 2002
Randomized Controlled Trial Comparative Study Clinical TrialPulmonary-to-systemic blood flow ratio effects of sevoflurane, isoflurane, halothane, and fentanyl/midazolam with 100% oxygen in children with congenital heart disease.
The cardiovascular effects of volatile anesthetics in children with congenital heart disease have been studied, but there are limited data on the effects of anesthetics on pulmonary-to-systemic blood flow ratio (Qp:Qs) in patients with intracardiac shunting. In this study, we compared the effects of halothane, isoflurane, sevoflurane, and fentanyl/midazolam on Qp:Qs and myocardial contractility in patients with atrial (ASD) or ventricular (VSD) septal defects. Forty patients younger than 14 yr old scheduled to undergo repair of ASD or VSD were randomized to receive halothane, sevoflurane, isoflurane, or fentanyl/midazolam. Cardiovascular and echocardiographic data were recorded at baseline, randomly ordered 1 and 1.5 mean alveolar anesthetic concentration (MAC) levels, or predicted equivalent fentanyl/midazolam plasma levels. Ejection fraction (using the modified Simpson's rule) was calculated. Systemic (Qs) and pulmonary (Qp) blood flow was echocardiographically assessed by the velocity-time integral method. Qp:Qs was not significantly affected by any of the four regimens at either anesthetic level. Left ventricular systolic function was mildly depressed by isoflurane and sevoflurane at 1.5 MAC and depressed by halothane at 1 and 1.5 MAC. Sevoflurane, halothane, isoflurane, or fentanyl/midazolam in 1 or 1.5 MAC concentrations or their equivalent do not change Qp:Qs in patients with isolated ASD or VSD. ⋯ Sevoflurane, halothane, isoflurane, and fentanyl/midazolam do not change pulmonary-to-systemic blood flow ratio in children with atrial and ventricular septal defects when administered at standard anesthetic doses with 100% oxygen.
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Anesthesia and analgesia · Nov 2002
Randomized Controlled Trial Comparative Study Clinical TrialIntrathecal versus IV fentanyl in pediatric cardiac anesthesia.
Systemic large-dose opioids are widely used in pediatric cardiac anesthesia, but there are no randomized, prospective studies regarding the use of intrathecal (IT) opioids for these procedures. In this randomized, prospective study, we compared cardiovascular and neurohumoral responses during IT or IV fentanyl anesthesia for pediatric cardiac surgery. Thirty children aged 6 mo to 6 yr were anesthetized with an IV fentanyl bolus of 10 micro g/kg. This was followed by a fentanyl infusion of 10 micro g. kg(-1). h(-1) (Group IV; n = 10), 2 micro g/kg of IT fentanyl (Group IT; n = 10), or combined IV and IT protocols (Group IV + IT; n = 10). Heart rate, mean arterial blood pressure, additional fentanyl doses, time to first analgesic requirement, COMFORT and Children's Hospital of Eastern Ontario Pain Scale scores, and extubation time were recorded. Blood cortisol, insulin, glucose, and lactate levels were measured presurgery, poststernotomy, during the rewarming phase of cardiopulmonary bypass (CPB), and 6 and 24 h after surgery. The patients' urinary cortisol excretion rates were also measured during the first postoperative day. The findings in all three groups were statistically similar, except for higher blood glucose levels during CPB in Group IT compared with Group IV (P < 0.004). Group IV + IT was the only group in which the increases in heart rate and mean arterial blood pressure from presurgery to poststernotomy were not significant. The 24-h urinary cortisol excretion rates ( micro g. kg(-1). d(-1)) were 61.51 +/- 39, 92.54 +/- 67.55, and 40.15 +/- 29.69 for Groups IV, IT, and IV + IT, respectively (P > 0.05). A single IT injection of fentanyl 2 micro g/kg offers no advantage over systemic fentanyl (10 micro g/kg bolus and 10 micro g. kg(-1). h(-1)) with regard to hemodynamic stability or suppression of stress response. The combination of these two regimens may provide better hemodynamic stability during the pre-CPB period and may be associated with a decreased 24-h urinary cortisol excretion rate. ⋯ In this prospective, randomized study, we investigated the adequacy of a single intrathecal injection of fentanyl for intraoperative analgesia, compared the effects of IT and IV fentanyl on stress response, and assessed for an additive effect of IT and IV fentanyl administration in pediatric cardiac anesthesia. The results with these three different anesthetic regimens were similar regarding anesthesia depth and level of stress response. However, the combination of IT and IV routes may provide better hemodynamic stability and a less pronounced stress response, as reflected by 24-h urinary cortisol excretion.
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Anesthesia and analgesia · Nov 2002
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of metoclopramide and lidocaine for preventing pain on injection of diazepam.
We compared the ability of metoclopramide with IV lidocaine pretreatment to abolish pain from a diazepam injection. In a randomized, prospective, double-blinded, placebo-controlled clinical trial, 159 patients (ASA physical status I and II), aged 20-70 yr old, were allocated to one of three groups. Placebo and study drugs were injected IV immediately before 0.1 mg/kg of diazepam into a dorsal hand vein. Patients in Groups 1, 2, and 3 received 2 mL of placebo, 2 mL of lidocaine 1%, and 2 mL of metoclopramide (10 mg), respectively. The patient's response was graded using a 4-point scale. Any score other than 0 represented pain on injection. We observed that the incidence of pain on diazepam injection was 83% in the placebo group, which was decreased to 70% and 39% in patients pretreated with metoclopramide and lidocaine, respectively. Although there was no significant difference in the incidence of pain in Groups 1 and 3 (P > 0.05), Group 3 showed significantly less patients with severe pain scores than Group 1 as diazepam was injected (P < 0.000). Group 2 showed a significantly less frequent incidence of pain than the saline (P < 0.000) and the metoclopramide (P < 0.002) groups as diazepam was injected. The intensity of pain in Group 2 was significantly less than Group 3 (P = 0.012). The intensity of diazepam injection pain was intense with placebo as compared with other groups (P < 0.000). Metoclopramide, rather than lidocaine pretreatment, may be a reasonable analgesic alternative for painful injections. ⋯ Metoclopramide, rather than lidocaine pretreatment, may be a reasonable analgesic alternative to decrease pain from a diazepam injection, especially when there is a medical condition in which lidocaine should be used very cautiously.
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Anesthesia and analgesia · Nov 2002
Randomized Controlled Trial Comparative Study Clinical TrialAttenuation of pain in a randomized trial by suppression of peripheral nociceptive activity in the immediate postoperative period.
Peripheral neuronal barrage from tissue injury produces central nervous system changes that contribute to the maintenance of postoperative pain. The therapeutic approaches to blocking these central changes remain controversial, because previous studies have not differentiated presurgical interventions from those administered after tissue injury, yet before pain onset. In this study, we evaluated the relative contributions of blockade of nociceptive input during surgery or during the immediate postoperative period on pain suppression. Subjects were randomly allocated to one of four groups: preoperative 2% lidocaine, postoperative 0.5% bupivacaine, both, or placebo injections. General anesthesia was induced and third molars extracted. Pain was assessed over 4 h and at 24 and 48 h. The beta-endorphin in blood samples increased twofold during surgery, which is indicative of activation of the peripheral nociceptive barrage in response to painful stimuli. Pain was decreased in the immediate postoperative period in the bupivacaine groups, whereas it increased in the lidocaine group over time. Pain intensity was less 48 h after surgery in the groups whose postoperative pain was blocked by the administration of bupivacaine, but no effect was demonstrated for the preoperative administration of lidocaine alone. These results in the oral surgery pain model suggest that minimizing the peripheral nociceptive barrage during the immediate postoperative period decreases pain at later time periods. In contrast, blocking the intraoperative nociceptive barrage does not appear to contribute significantly to the subsequent reduction in pain. ⋯ Suppression of postoperative pain immediately after surgery attenuates the pain experienced 1 to 2 days after surgery. These findings suggest that pain after minor surgery can be prevented by blocking the development of pain processes that amplify pain for days after surgery.