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Randomized controlled trial to examine the influence of thoracic epidural analgesia on postoperative ileus after laparoscopic sigmoid resection.

BACKGROUND: The aim of the study was to evaluate whether perioperative epidural analgesia had any effect on the duration of postoperative ileus after laparoscopic sigmoid resection. METHODS: Twenty patients were randomized to surgery either with (group 1; n = 10) or without (group 2; n = 10) thoracic epidural analgesia. The major endpoint of the study was the time to the first postoperative bowel movement. Secondary endpoints were the interval until oral feeding was tolerated, incidence of postoperative vomiting, postoperative analgesic consumption use of patient-controlled analgesia (PCA) until the fourth day after operation, subjective pain perception and the incidence of epidural-related side-effects. RESULTS: Age, sex and American Society of Anesthesiologists classification were similar in the two groups. The first bowel movement was documented after a median of 54 (95 per cent confidence interval 32-127) h in group 1 and 77 (31-99) h in group 2 (P = 0.8). Oral feeding without additional parenteral therapy was tolerated after 48 (40-64) h in group 1 and after 56 (48-64) h in group 2 (P = 0.6). Postoperative vomiting occurred in two patients from each group. During epidural therapy the use of PCA was lower in group 1 (0.30 (0.19-0.96) mg morphine per kg) than in group 2 (0.56 (0.37-0. 80) mg/kg) (P < 0.05). Postoperative pain perception during rest and while coughing was similar in both groups. Three patients experienced reversible side-effects of epidural therapy (motor deficit, two patients; bladder dysfunction, one). CONCLUSION: Perioperative thoracic epidural analgesia did not have a clinically relevant effect on the duration of postoperative ileus after laparoscopic sigmoid resection.

Aged↗

Role of the central endogenous opiate system in patients with syndrome X.

BACKGROUND: To evaluate the role of the endogenous opioid system (EOS) in abnormal pain perception in patients with syndrome X, we used a neuroendocrine approach, evaluating plasmatic luteinizing hormone (LH) changes after naloxone, a competitive antagonist of opioid receptors able to unblock tonic EOS inhibition on gonadotropin release. Thus LH response to naloxone test indicates the central EOS activity on hypothalamic luteinizing hormone-releasing hormone (LH-RH) inhibitory opioid receptors. METHODS: Ten patients with syndrome X, 10 age-matched male patients with coronary artery disease (CAD), and 10 normal subjects were analyzed. Naloxone tests were performed between 8 and 9 am. Basal beta-endorphin and LH levels were determined on 4 blood samples at 20-minute intervals; after naloxone (0.1 mg/kg intravenously in 4 minutes), LH was measured on 8 samples at 15-minute intervals. In all patients the test was also performed after LH-RH administration. Anginal pain on exercise testing was subjectively scored on a 1 to 10 analogic scale and wall motion abnormalities were quantified by a wall motion score index. RESULTS: Significant differences were found in LH release after naloxone (CAD 260.3 +/- 42.6 vs syndrome X 151.6 +/- 48.5 mIU/mL, P <.05), angina score (CAD 5.5 +/- 1.3 vs syndrome X 7.2 +/- 1.7, P <.05), and wall motion abnormalities (CAD 3.6 +/- 1. 2 vs syndrome X 2.8 +/- 1.9, P <.05). CONCLUSIONS: The reduced LH release after naloxone in syndrome X, with a normal LH-RH response, suggests a lower central EOS activity, which may be related to the higher anginal pain perception.

Humans↗

Distribution of local anesthetic solution in retromediastinal block. Preliminary experimental results.

BACKGROUND AND OBJECTIVES: Interpleural anesthesia blocks pain perception from the thoracoabdominal wall without impairment of leg function. Bilateral interpleural anesthesia is not recommended because of possible bilateral impairment of respiratory function. Infiltration of the retromediastinum with local anesthetic might cause bilateral thoracoabdominal somatic block and block of sympathetic afferents from the abdominal cavity without impairing respiration. METHOD: Distribution of stained fluid was studied after injection into the retromediastinum through a catheter placed about 10 cm cephalad to the diaphragm via the esophageal hiatus in three human cadavers of normal size and in six anesthetized pigs of 20-30 kg. In the pigs serum levels of bupivacaine were measured after injection of 10 mL of 0.5% bupivacaine stained with 1 mL of methylene blue. RESULTS: The injected Dye stained intercostal nerves 6-11 in cadavers and 5-12 in pigs symmetrically on both sides, along with the adjacent parts of the sympathetic chain and both vagal nerves but not the phrenic nerves. During the sampling period of 50-60 minutes, bupivacaine serum concentrations rose slowly to a maximum of 4.2 micrograms/mL. CONCLUSIONS: Block of pain perception from the abdominal wall and cavity is possible by injection of local anesthetic into the retromediastinum via a catheter introduced through the esophageal diaphragm hiatus. The block would not be expected to impair respiratory or leg function. Its efficacy and safety have yet to be established.

Adult↗

Changes in beta-endorphin levels in response to aerobic and anaerobic exercise.

Exercise-induced increases in the peripheral beta-endorphin concentration are mainly associated both with changes in pain perception and mood state and are possibly of importance in substrate metabolism. A more precise understanding of opioid function during exercise can be achieved by investigating the changes in beta-endorphin concentrations dependent upon intensity and duration of physical exercise and in comparison to other stress hormones. Published studies reveal that incremental graded and short term anaerobic exercise lead to an increase in beta-endorphin levels, the extent correlating with the lactate concentration. During incremental graded exercise beta-endorphin levels increase when the anaerobic threshold has been exceeded or at the point of an overproportionate increase in lactate. In endurance exercise performed at a steady-state between lactate production and elimination, blood beta-endorphin levels do not increase until exercise duration exceeds approximately 1 hour, with the increase being exponential thereafter. beta-Endorphin and ACTH are secreted simultaneously during exercise, followed by a delayed release of cortisol. It is not yet clear whether a relationship exists between the catecholamines and beta-endorphin. These results support a possible role of beta-endorphin in changes of mood state and pain perception during endurance sports. In predominantly anaerobic exercise the behaviour of beta-endorphin depends on the degree of metabolic demand, suggesting an influence of endogenous opioids on anaerobic capacity or acidosis tolerance. Further investigations are necessary to determine the role of beta-endorphin in exercise-mediated physiological and psychological events.

Affect↗

Fibromyalgia--a syndrome associated with decreased nocturnal melatonin secretion.

OBJECTIVE: Most patients with fibromyalgic syndrome (FMS) complain of sleep disturbances, fatigue, and pain. These symptoms might be a consequence of changed melatonin (MT) secretion, since MT is known to have sleep promoting properties. Moreover, serum concentrations of two MT precursors (tryptophan and serotonin)--affecting both sleep and pain perception--appear to be low in patients with FMS. Therefore, the objective of this investigation was to study whether serum MT (s-MT) level is also low in these patients. DESIGN: Eight patients with FMS and 8 healthy sex-, BMI-, and age-matched controls were included in the study. s-MT concentrations were determined every second hour between 1800 and 0800 h. Urine was collected between 2200 and 0700 h for determination of urinary MT excretion. To evaluate total MT secretion between 1800 and 0800 h and MT secretion during the hours of darkness (between 23 and 07 h) individual MT areas under the curve (AUC) were calculated and expressed as group means. RESULTS: The FMS patients had a 31% lower MT secretion than healthy subjects during the hours of darkness (MT AUC 2300-0700 h (mean +/- SEM): 1.70 +/- 0.17 vs 2.48 +/- 0.38 nmol/l; P < 0.05). Also the s-MT peak value was significantly lower in the patient group: 0.28 +/- 0.03 vs 0.44 +/- 0.06 nmol/l; P < 0.05). CONCLUSION: Patients with fibromyalgic syndrome have a lower melatonin secretion during the hours of darkness than healthy subjects. This may contribute to impaired sleep at night, fatigue during the day, and changed pain perception.

Adult↗

Nitric oxide-producing islet cells modulate the release of sensory neuropeptides in the rat substantia gelatinosa.

The substantia gelatinosa of the spinal cord (lamina II) is the major site of integration for nociceptive information. Activation of NMDA glutamate receptor, production of nitric oxide (NO), and enhanced release of substance P and calcitonin gene-related peptide (CGRP) from primary afferents are key events in pain perception and central hyperexcitability. By combining reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase histochemistry for NO-producing neurons with immunogold labeling for substance P, CGRP, and glutamate, we show that (1) NO-producing neurons in lamina IIi are islet cells; (2) these neurons rarely form synapses onto peptide-immunoreactive profiles; and (3) NADPH diaphorase-positive dendrites are often in close spatial relationship with peptide-containing terminals and are observed at the periphery of type II glomeruli showing glutamate-immunoreactive central endings. By means of confocal fluorescent microscopy in acute spinal cord slices loaded with the Ca2+ indicator Indo-1, we also demonstrate that (1) NMDA evokes a substantial [Ca2+]i increase in a subpopulation of neurons in laminae I-II, with morphological features similar to those of islet cells; (2) a different neuronal population in laminae I-IIo, unresponsive to NMDA, displays a significant [Ca2+]i increase after slice perfusion with either substance P and the NO donor 3morpholinosydnonimine (SIN-1); and (3) the responses to both substance P and SIN-1 are either abolished or significantly inhibited by the NK1 receptor antagonist sendide. These results provide compelling evidence that glutamate released at type II glomeruli triggers the production of NO in islet cells within lamina IIi after NMDA receptor activation. The release of substance P from primary afferents triggered by newly synthesized NO may play a crucial role in the cellular mechanism leading to spinal hyperexcitability and increased pain perception.

Animals↗

[On the physiology and pharmacology of endorphins (author's transl)].

Endorphins are peptides with opiate-like action synthesized in various tissue, e.g. in intestine and central nervous system. Exact characterization of opioid-specific receptors and sensitive biological test assays for opioids were prerequisites for the discovery of these substances. Met- and leu-enkephalin were the first endorphins discovered. Both are pentapeptides. One of them, namely met-enkephalin (H-Tyr-Gly-Gyl-Phe-Met-OH) is likely to be a fragment of the peptides alpha- and beta-endorphin, both showing opioid-like actions, as well as of beta-lipotropin, a polypeptide showing no opioid-like activity: all these peptides include the pentapeptide met-enkephalin within their molecules. beta-liportropin and ACTH are likely to be fragments of a common precursor. At least both enkephalins (which are studied better as yet than the other endorphins) are supposed to be formed in the soma of the neuron and transported to the nerve ending, where they are released. They seem to have the function of neuromodulator or even of neurotransmitters. The pharmacological actions of endorphins resemble those of "classical opiates", both having e.g. analgesic effects. Both enkephalins are, among various other brain and spinal cord areas, localized in those areas which seem to be of particular relevance for perception and transmission of pain. They might, under certain conditions, play some part in the regulation of pain perception. Furthermore, they seem to be relevant for some neuroendocrine processes. Their relevance in symptoms of schizophrenic psychoses seems to be more doubtful. In opiate dependence no significant alterations of endorphin concentrations could be observed as yet.

Animals↗

A randomized comparison of post-operative pain, quality of life, and physical performance during the first 6 weeks after abdominal or vaginal surgical correction of descensus uteri.

AIMS: With respect to urogenital function, vaginal hysterectomy combined with anterior and/or posterior colporraphy has been shown to be superior to abdominal sacrocolpopexy with preservation of the uterus. We performed a randomized trial to compare the effects of both procedures on pain, quality of life and physical performance during the first six weeks after surgery. METHODS: Eighty-two patients were randomized to have surgery either by vaginal or abdominal approach. All patients were asked to complete the RAND-36 before surgery and 6 weeks after surgery and to keep a diary for the first 6 weeks after surgery. This diary assessed the pain perception and use of pain medication, bother of limitations due to the surgery and performance of daily activities after surgery. These outcomes were compared. RESULTS: All patients completed the RAND-36 and 68 patients completed the diary. Patients who had undergone abdominal surgery had a statistically lower score on the health change domain (56 vs 68), bodily pain domain (63 vs 80) and mental health domain (74 vs 81) of the RAND-36, as compared to patients who had undergone vaginal prolapse surgery. During hospital stay, the abdominal group experienced on average more days of pain (4.5 vs 3.0) and impaired mobility (3.7 vs 2.9) as compared to the vaginal group. Patients received more pain medication following abdominal surgery as compared to vaginal surgery. CONCLUSIONS: The vaginal operation to correct a descensus uteri is associated with less pain, better quality of life and better mobility during the first 6 weeks of the recovery period as compared to the abdominal approach.

Abdomen↗

Repetitive transcranial magnetic stimulation of dorsolateral prefrontal cortex increases tolerance to human experimental pain.

Dorsolateral prefrontal cortex (DLPFCx) has been implicated in pain perception and in a pain modulation pathway. However, the precise participation of this region is not completely understood. The aim of this study was to evaluate whether 1 Hz rTMS of DLPFCx modifies threshold and tolerance in experimental pain. The effect of 1 Hz rTMS during 15 min at 100% motor threshold was tested in one hundred and eighty right-handed healthy volunteers, using a parallel-group stimulation design. The stimulation sites were right or left DLPFCx, right or left motor cortex, vertex or sham. rTMS was applied in two experimental contexts: (1) To evaluate its transitory effect (interference or facilitation) during cold pressor threshold (CPTh) and tolerance (CPTt) and (2) to evaluate its long-term effect by stimulating before CPTh, CPTt, pain heat thermal threshold, pain pressure threshold and tolerance. During rTMS of right DLPFCx, an increase in left hand CPTt (mean +/- SD; 17.63 s +/- 5.58 to 30.94 s +/- 14.84, P < 0.001) and in right hand CPTt (18.65 s +/- 6.47 to 26.74 s +/- 11.85, P < 0.001) were shown. No other stimulation site modified any of the pain measures during or after rTMS. These results show that 1 Hz rTMS of right DLPFCx has a selective effect by increasing pain tolerance and also sustains a right hemisphere preference in pain processing.

Adolescent↗

A survey of perceptions with pain management in Spanish inpatients.

The aim of this study was to document the satisfaction with pain management in a Spanish inpatient population and its relationship with pain ratings. Two hundred fifty inpatients of four departments were interviewed: Surgery, Orthopedics, Gynecology, and Internal Medicine. A 32-item questionnaire was used, and the main variables evaluated were pain severity, dissatisfaction with pain management and caregivers, and patient expectations regarding pain relief. Relationships among the variables were analyzed by means of Spearman's correlation between item scores and regression analysis. Median satisfaction scores were consistent with "very satisfied." Mean (SD) worst pain during the past 24 hours was 68.8 (27.5) on a 100 mm visual analogue scale. "Dissatisfaction with Pain Management" correlated positively with "Dissatisfaction with Medical Staff" (0.42), and inversely with "Pain Now" (-0.41) and "Expected Pain Relief" (-0.38). Regression analysis showed that "Dissatisfaction with Pain Management" was dependent on "Pain Now," "Least Pain," and "Dissatisfaction with Medical Staff," with statistically significant beta weight values of 0.277, 0.197, and 0.280, respectively. The study shows that patients were highly satisfied with pain management, even when they were in pain. Moreover, it establishes that patient dissatisfaction with treatment was highly related to the satisfaction with caregivers and pain intensity.

Attitude to Health↗

Rofecoxib attenuates both primary and secondary inflammatory hyperalgesia: a randomized, double blinded, placebo controlled crossover trial in the UV-B pain model.

The analysis of drug's influence on peripheral and central sensitisation can give useful information about its mode of action and can lead to more efficacy in the treatment of pain. Peripheral inflammation is associated with peripheral expression and up-regulation of cyclooxygenase 2 (COX-2) in the CNS. The relative contribution of COX-2 mediated central sensitisation may be prominent under inflammatory conditions. In this randomized, double blinded, placebo controlled cross-over trial the effects of multidoses of the COX-2 selective inhibitor rofecoxib on primary and secondary hyperalgesia were evaluated in the UVB pain model. Twenty-four hours after local UVB irradiation at the upper leg of 42 healthy volunteers heat pain perception (HPPT) and heat pain tolerance thresholds (HPTT) were assessed within the inflammation. The area of secondary hyperalgesia was determined by pin prick test. Subjects received oral rofecoxib 50, 250, 500 mg or placebo. Pain testing was repeated after 3 and 6 h. Compared to placebo, rofecoxib significantly increased HPPT (1.55 and 1.08 degrees C, P<0.0001 and P=0.0333), HPTT (1.74 and 1.58 degrees C, P<0.0001 and P<0.0001), and reduced the mean area of secondary hyperalgesia by 15.6% (P=0.007) and 16.8% (P<0.001) after 3 and 6 h. No significant difference between the three dosage groups was observed. These data confirm peripheral effects of rofecoxib in a human inflammatory UV-B pain model and provide circumstantial evidence that even a standard clinical dose of rofecoxib reduces central hyperalgesia in inflammatory pain. We confirm that the effect of single oral dose of rofecoxib plateaus at 50 mg.

Adult↗

Stress reactivity and perception of pain among tension headache sufferers.

Twenty-one tension headache sufferers and 21 control subjects were exposed to a series of psychological stressors and an ischemic pain task, involving a tourniquet around the arm. Compared to control subjects, headache patients showed higher heart rates and evidence of more prolonged vasoconstriction in the hands and the ear lobe. No between-group differences in EMG were found, however. Headache patients rated the tourniquet as more painful than did control subjects, and described themselves as more anxious, angry, and depressed. The pattern of results is consistent with the interpretation that headache patients are emotionally and autonomically hyperreactive to pain and to psychological stress.

Adult↗

Patients' perceptions of pain with spinal, intramuscular, and venous injections.

Most of 46 patients believed that spinal injection would be more painful than intramuscular or intravenous injections. The reverse proved true: spinal injections were perceived to be less painful than the other two procedures. Intramuscular injections should be avoided. Local anaesthesia should be given for lumbar punctures and intravenous cannulation.

Adolescent↗

Targeted toxins in pain.

Although only recently applied to the study of nociception, 'molecular neurosurgery', producing highly selective neural lesions using targeted cytotoxins, has proven a valuable tool for analysis of nociceptive systems and promises to yield much more information on the role of specific types of neurons in pain perception and possibly new pain therapies. Neuropeptide-toxin conjugates, particularly, substance P-saporin, have proven useful research tools and may find clinical applications. Targeting non-lethal moieties (enzymes, genes, viruses) also may prove useful for research and therapeutic purposes.

Animals↗

Spouses' and physicians' perceptions of pain severity in older women with osteoarthritis: dyadic agreement and patients' well-being.

This study examined agreement between patients and two role partners (spouses and physicians) on patients' pain severity and the relationships between dyadic agreement and patients' well-being. We hypothesized that compared to disagreement between patients and role partners, dyadic agreement would be related to better psychological well-being (more disease-specific self-efficacy and positive affect, and less depression). Participants were 114 older women with osteoarthritis, their caregiving husbands, and their rheumatologists. Among patient-spouse dyads, agreement was associated with better well-being, especially when compared to spouses' underestimation of patients' pain. Contrary to predictions, patient-physician agreement was not related to better patient well-being. Agreement between patients and physicians was associated with less (rather than more) self-efficacy and positive affect when compared to physicians' underestimation of patients' pain.

Aged↗

Avoidance versus focused attention and the perception of pain: differential effects for men and women.

The aim of the current investigation was to compare the effects of two different attentional strategies (focused vs. avoidance) on how males and females respond to experimentally induced pain. One hundred healthy adults were instructed to either attend towards or away from cold pressor pain. Measures of pain tolerance, pain threshold and recovery were taken, as were self-report measures of sensory and affective pain experiences. As expected, gender was found to moderate tolerance to pain: males were found to be more tolerant to cold pressor pain than females. With respect to the self-report measures, males reported less sensory pain when they attended toward the pain than when they avoided it. However, a similar effect was not found in women, suggesting that attentional focusing may only be a useful strategy for males. These results are discussed in light of previous research.

Adaptation, Psychological↗

Women's perception of pain and distress during intravenous catheterization and urethral mini-catheterization.

A study was done to prospectively compare the pain and distress of urethral mini-catheterization (MC) with the pain and distress of intravenous (IV) catheterization in women. Ten-centimeter visual analog scales were used on which the left end represented "no pain" or "no distress" and the right "the worst pain imaginable" or "extreme distress." Distress was defined to include embarrassment, anxiety, or fear. A convenience sample of 40 adult women who presented to a university emergency department and were undergoing both procedures as part of their management appraised pain and distress after IV placement and urethral MC. The mean IV pain score was 4.2 cm, whereas the mean MC score was only 2.6 cm (P = .02). The IV and MC distress score means were similar (2.3 v 2.6 cm, P = .55). These results suggest that patients perceive urethral MC as less painful than IV placement. The distress scores of these two procedures did not differ and were low in both instances.

Adolescent↗