Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2006
Comparative StudyMagnetic resonance spectroscopy detects biochemical changes in the brain associated with chronic low back pain: a preliminary report.
Magnetic resonance (MR) spectroscopy is a noninvasive technique that can be used to detect and measure the concentration of metabolites and neurotransmitters in the brain and other organs. We used in vivo (1)H MR spectroscopy in subjects with low back pain compared with control subjects to detect alterations in biochemistry in three brain regions associated with pain processing. A pattern recognition approach was used to determine whether it was possible to discriminate accurately subjects with low back pain from control subjects based on MR spectroscopy. ⋯ Spectra were analyzed and compared between groups using a pattern recognition method (Statistical Classification Strategy). Using this approach, it was possible to discriminate between subjects with low back pain and control subjects with accuracies of 100%, 99%, and 97% using spectra obtained from the anterior cingulate cortex, thalamus, and prefrontal cortex, respectively. These results demonstrate that MR spectroscopy, in combination with an appropriate pattern recognition approach, is able to detect brain biochemical changes associated with chronic pain with a high degree of accuracy.
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Anesthesia and analgesia · Apr 2006
Comparative StudyFibrinogen concentrate reverses dilutional coagulopathy induced in vitro by saline but not by hydroxyethyl starch 6%.
Severe bleeding often induces coagulopathy via loss, consumption, and dilution of clotting factors and platelets. The aims of our in vitro study were to characterize the influence of progressive hemodilution with either NaCl 0.9% or hydroxyethyl starch (HES) 6% on blood clot formation and to analyze the effect of substitution of fibrinogen and platelets on dilutional coagulopathy. Whole blood samples drawn from 8 volunteers were diluted from 20% to 80% of the sample volume with both diluents separately. ⋯ Platelets alone or in addition were not able to improve clot firmness to a clinically relevant extent. Dilutional coagulopathy induced by crystalloids can, in vitro, be effectively reversed by supplementation of fibrinogen. In contrast, HES molecules interfere with fibrin polymerization and, thus, administration of fibrinogen after dilution with HES 6% failed to significantly improve clot firmness.
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Anesthesia and analgesia · Apr 2006
Comparative StudyPostoperative delirium: the importance of pain and pain management.
Postoperative delirium is common in geriatric patients. Few studies have examined events in the postoperative period that may contribute to the occurrence of postoperative delirium. We hypothesized that postoperative delirium is related to postoperative pain and/or pain management strategy. ⋯ By multivariate logistic regression, age (odds ratio [OR], 2.5; 95% confidence interval [CI] 1.5 to 4.2), moderate (OR, 2.2; 95% CI 1.2 to 4.0) and severe (OR, 3.7; 95% CI 1.5 to 9.0) preoperative resting pain, and increase in level of pain from baseline to postoperative day one (OR, 1.1; 95% CI 1.01 to 1.2) were independently associated with a greater risk for the development of postoperative delirium. In contrast, patients who used oral opioid analgesics as their sole means of postoperative pain control were at decreased risk of developing delirium in comparison with those who used opioid analgesics via IV patient-controlled analgesia technique (OR, 0.4; 95% CI 0.2 to 0.7). These results validate our hypothesis that pain and pain management strategies are important factors related to the development of postoperative delirium in elderly patients.
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Anesthesia and analgesia · Apr 2006
Comparative StudySkin temperature during regional anesthesia of the lower extremity.
Increase in skin temperature (Ts) occurs early during neuraxial blocks. However, the reliability of Ts to predict successful peripheral block is unknown. Therefore, we investigated whether an increase in Ts more than 1 degrees C precedes or follows an impairment of sensation after combined femoral and sciatic nerve block as well as after epidural anesthesia. ⋯ We conclude that an increase of Ts is a reliable, but late, sign of successful sciatic nerve block. Therefore it is of limited clinical value. Ts changes after femoral nerve block are negligible and late.
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Anesthesia and analgesia · Apr 2006
Comparative StudyEtomidate depresses lumbar dorsal horn neuronal responses to noxious thermal stimulation in rats.
Etomidate is a widely used IV anesthetic, but little is known about its analgesic properties, in particular, its effects on spinal cord neuronal responses to noxious stimuli. We hypothesized that etomidate would depress lumbar neuronal responses to noxious heat. Rats (n = 15) were anesthetized with isoflurane (1.2%) and laminectomy was performed to record single unit activity. ⋯ The responses quickly recovered, usually by the 10-min period postinjection. Similar responses were obtained in decerebrate, isoflurane-free rats administered etomidate and in isoflurane-anesthetized rats administered propofol. These data demonstrate that etomidate depresses spinal cord neuronal responses to noxious stimulation and is a possible mechanism by which this drug might produce analgesia.