Anesthesiology
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Randomized Controlled Trial Comparative Study
A comparison of the effect of high- and low-dose fentanyl on the incidence of postoperative cognitive dysfunction after coronary artery bypass surgery in the elderly.
Postoperative cognitive dysfunction (POCD) after coronary artery bypass graft surgery is a common complication for which, despite many clinical investigations, no definitive etiology has been found. The current use of both high- and low-dose fentanyl as anesthetic techniques allowed us to investigate the effect of fentanyl on the incidence of POCD. ⋯ High-dose fentanyl is not associated with a difference in the incidence of POCD at 3 or 12 months after surgery. Low-dose fentanyl leads to shorter postoperative ventilation times and may be associated with a greater incidence of POCD 1 week after surgery. Early POCD is associated with an increased duration of stay in the hospital.
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Randomized Controlled Trial
Basal heat pain thresholds predict opioid analgesia in patients with postherpetic neuralgia.
A variety of analgesics have been studied in the treatment of postherpetic neuralgia, with several medications demonstrating some degree of efficacy. However, existing trials have documented large individual differences in treatment responses, and it is important to identify patient characteristics that predict the analgesic effectiveness of particular interventions. Several animal studies have indicated that reduced basal nociceptive sensitivity, in the form of relatively high heat pain thresholds, is associated with greater opioid analgesia, but this finding has not been applied to human studies of opioid treatment for chronic pain. ⋯ These findings, which will require replication, suggest that pretreatment assessment of heat pain sensitivity might prove useful in identifying those patients most likely to respond to opioids.
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Randomized Controlled Trial
Differences between midazolam and propofol sedation on upper airway collapsibility using dynamic negative airway pressure.
Upper airway obstruction (UAO) during sedation can often cause clinically significant adverse events. Direct comparison of different drugs' propensities for UAO may improve selection of appropriate sedating agents. The authors used the application of negative airway pressure to determine the pressure that causes UAO in healthy subjects sedated with midazolam or propofol infusions. ⋯ At the mild to moderate level of sedation studied, midazolam and propofol sedation resulted in the same propensity for UAO. In this homogeneous group of healthy subjects, there was a considerable range of negative pressures required to cause UAO. The specific factors responsible for the maintenance of the upper airway during sedation remain to be elucidated.
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Randomized Controlled Trial
Fructose administration increases intraoperative core temperature by augmenting both metabolic rate and the vasoconstriction threshold.
The authors tested the hypothesis that intravenous fructose ameliorates intraoperative hypothermia both by increasing metabolic rate and the vasoconstriction threshold (triggering core temperature). ⋯ Preoperative fructose infusion helped to maintain normothermia by augmenting both metabolic heat production and increasing the vasoconstriction threshold.
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Randomized Controlled Trial
Mechanism-based pharmacokinetic-pharmacodynamic modeling of the antinociceptive effect of buprenorphine in healthy volunteers.
The objective of this investigation was to characterize the pharmacokinetic-pharmacodynamic relation of buprenorphine's antinociceptive effect in healthy volunteers. ⋯ This is consistent with observations in rats, suggesting that the rate-limiting step in the onset and offset of the antinociceptive effect is biophase distribution rather than slow receptor association-dissociation. In the dose range studied, no saturation of receptor occupancy occurred explaining the lack of a ceiling effect for antinociception.