Anesthesia and analgesia
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Rapid opioid dose escalation, possibly caused by tolerance, has been observed in some patients on daily opioid therapy, although clinically identifiable characteristics of these patients are unknown. In this retrospective chart review of 206 patients, we examined whether the age of the patient was related to opioid escalation. Initial starting doses of long-acting opioids were similar in younger patients (< or =50 yr; 49 +/- 3 mg/d oral morphine-equivalent dose) versus older patients (> or =60 yr; 42 +/- 3 mg/d). ⋯ Only older patients demonstrated a reduction in visual analog scale scores from start of opioid therapy until discharge from the clinic (6.9 +/- 0.3 to 5.6 +/- 0.3; P < 0.01). These clinical data suggest that age is an important variable in opioid dose escalation. Although factors other than opioid tolerance can result in dose escalation, it is possible that older patients may have a reduced rate of tolerance development.
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Anesthesia and analgesia · Jun 2005
Clinical TrialThromboelastography maximum amplitude predicts postoperative thrombotic complications including myocardial infarction.
Postoperative thrombotic complications increase hospital length of stay and health care costs. Given the potential for thrombotic complications to result from hypercoagulable states, we sought to determine whether postoperative blood analysis using thromboelastography could predict the occurrence of thrombotic complications, including myocardial infarction (MI). We prospectively enrolled 240 patients undergoing a wide variety of surgical procedures. ⋯ Furthermore, the percentage suffering postoperative MI in the increased MA group (6 of 95 = 6.3%) was significantly larger than that in the MA < or =68 group (0 of 145 = 0%) (P = 0.0035). In a multivariate analysis, increased MA (P = 0.013; odds ratio, 1.16; 95% confidence interval, 1.03-1.20) and Goldman risk score (P = 0.046; odds ratio, 2.39; 95% confidence interval, 1.02-5.61) both independently predicted postoperative MI. A postoperative hypercoagulable state as determined by thromboelastography is associated with postoperative thrombotic complications, including MI, in a diverse group of surgical patients.
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Anesthesia and analgesia · Jun 2005
The NR3B subunit does not alter the anesthetic sensitivities of recombinant N-methyl-D-aspartate receptors.
The N-methyl-D-aspartate (NMDA) receptor NR3B subunit co-assembles with NR1 and NR2 subunits to form a receptor complex with distinct channel properties. In the present study, we investigated the effects of co-expression of the NR3B subunit on the anesthetic sensitivities of NMDA receptors for NR1/NR2 channels expressed in Xenopus oocytes. ⋯ Mutations of two amino acid residues in the NR3B subunit at positions homologous to the N and N + 1 sites in the NR1 and NR2 subunits, which constitute the blocking sites for Mg2+ and ketamine, did not affect the sensitivities of NR1/NR2B/NR3B channels to Mg2+, ketamine and isoflurane. Thus, the amino acid residues at the N and N + 1 sites in NR3 subunits are unlikely to be involved in the formation of channel blocking sites in NR1/NR2/NR3 channels.
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Anesthesia and analgesia · Jun 2005
Randomized Controlled Trial Clinical TrialThe influence of two different hydroxyethyl starch solutions (6% HES 130/0.4 and 200/0.5) on blood viscosity.
We performed the current study to investigate the influence of 2 different hydroxyethyl starch (HES) solutions, the novel medium molecular weight HES 130/0.4 (6%) and HES 200/0.5 (6%), on plasma and whole blood viscosity in vitro and ex vivo in patients with severe head injury. For the in vitro experiments, blood was incubated with increasing concentrations (0%-50% vol/vol plasma) of either 6% HES 130/0.4 or 6% HES 200/0.5 solution. Plasma viscosity and whole blood viscosity (hematocrit [Hct] 45%) at high (94.5 s(-1)) and low (0.1 s(-1)) shear rates were determined. ⋯ In both groups plasma and blood viscosity tended to increase over time without statistical significance. Although the prominent effects found in vitro are not in keeping with the ex vivo data, they are likely to reflect the true clinical situation during repetitive, large-dose HES administration. We therefore conclude that HES 130/0.4 may have hemorheological advantages over conventional HES 200/0.5 when used in large quantities.