Anesthesiology
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Randomized Controlled Trial Clinical Trial
Efficacy of two methods for reducing postbypass afterdrop.
Afterdrop, defined as the precipitous reduction in core temperature after cardiopulmonary bypass, results from redistribution of body heat to inadequately warmed peripheral tissues. The authors tested two methods of ameliorating afterdrop: (1) forced-air warming of peripheral tissues and (2) nitroprusside-induced vasodilation. ⋯ Cutaneous warming reduced the core temperature afterdrop by 60%. However, heat-balance data indicate that this reduction resulted primarily because forced-air heating prevented the typical decrease in body heat content after discontinuation of bypass, rather than by reducing redistribution. Nitroprusside administration slightly increased peripheral tissue temperature and heat content at the end of rewarming. However, the core-to-peripheral temperature gradient was low in both groups. Consequently, there was little redistribution in either case.
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Hypothermia during general anesthesia develops with a characteristic three-phase pattern. The initial rapid reduction in core temperature after induction of anesthesia results from an internal redistribution of body heat. Redistribution results because anesthetics inhibit the tonic vasoconstriction that normally maintains a large core-to-peripheral temperature gradient. ⋯ Postoperative return to normothermia occurs when brain anesthetic concentration decreases sufficiently to again trigger normal thermoregulatory defenses. However, residual anesthesia and opioids given for treatment of postoperative pain decreases the effectiveness of these responses. Consequently, return to normothermia often needs 2-5 h, depending on the degree of hypothermia and the age of the patient.
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Randomized Controlled Trial Clinical Trial
Low-dose clonidine and neostigmine prolong the duration of intrathecal bupivacaine-fentanyl for labor analgesia.
Intrathecal (IT) opioid and local anesthetic combinations are popular for labor analgesia because of rapid, effective pain relief, but the duration of analgesia is limited. This study was undertaken to determine whether the addition of clonidine and neostigmine to IT bupivacaine-fentanyl would increase the duration of analgesia without increasing side effects for patients in labor. ⋯ The addition of clonidine and neostigmine significantly increased the duration of analgesia from IT bupivacaine-fentanyl during labor, but neostigmine caused more nausea. Although serious side effects were not observed in this study, safety must be further addressed before the routine use of multiple IT drugs is advocated.
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Randomized Controlled Trial Clinical Trial
Preemptive intravenous morphine-6-glucuronide is ineffective for postoperative pain relief.
Morphine-6-glucuronide (M-6-G), a major metabolite of morphine, is reported to be more potent than morphine when administered intrathecally; however, its efficiency remains under debate when administered intravenously. This study was designed to assess the analgesic efficiency of intravenous M-6-G for the treatment of acute postoperative pain. ⋯ A single intravenous bolus dose of M-6-G was found to be ineffective in the treatment of acute postoperative pain. This might be related to the low permeability of the blood-brain barrier for M-6-G.
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Randomized Controlled Trial Clinical Trial
Efficacy of neurolytic celiac plexus block in varying locations of pancreatic cancer: influence on pain relief.
Neurolytic celiac plexus block (NCPB) is an effective way of treating severe pain in some patients with pancreatic malignancy. However, there are no studies to date that evaluate the effectiveness of NCPB related to the site of primary pancreas cancer. The aim of the study was to assess the effectiveness of NCPB in pancreatic cancer pain, depending on the location of the pancreatic tumor. ⋯ In this study, unilateral transcrural celiac plexus neurolysis has been shown to provide effective pain relief in 74% of patients with pancreatic cancer pain. Neurolysis was more effective in cases with tumor involving the head of the pancreas. In the cases with advanced tumor proliferation, regardless of the technique used, the analgesic effects of NCPB were not satisfactory.