Central poststroke pain: correlation of MRI with clinical pain characteristics and sensory abnormalities

OBJECTIVE: To correlate MRI and sensory changes in patients with spontaneous lesions in the cerebral "pain pathway." METHODS: The authors used MRI and quantitative somatosensory testing in 73 patients with central poststroke pain (CPSP) and in 13 patients with pain-free stroke with sensory deficit. RESULTS: Lesions in any part of the discriminatory somatosensory pathway may or may not produce CPSP. Most CPSP patients have multiple lesions, many probably unrelated to pain. Ventroposterior thalamic nuclear lesions are more likely to produce half-body pain than lesions elsewhere (including the brainstem). In supratentorial lesions, the greatest pain is more likely to be in an extremity, and in infratentorial lesions, the greatest pain is likely to be in the face. Supratentorial CPSP patients have a deficit of sharpness and cold (peripherally mediated by A delta fibers) than pain-free stroke patients, whereas patients with infratentorial CPSP additionally have a deficit of C-fiber-mediated warmth and hot pain. Burning pain is more common than nonburning pain in younger patients. Warmth and cold, but not hot pain, exhibiting central convergence (spatial summation) are more affected in CPSP patients with burning than nonburning pain. Allodynic CPSP patients had a significantly greater deficit for warmth than patients without allodynia. CONCLUSIONS: Different stroke sites produce different patterns of sensory deficit. The progression from painless sensory deficit to CPSP is not purely quantitative.     

Control of postoperative pain with intrapleural analgesia

INTRODUCTION: Personal experience in the treatment of postoperative pain using intrapleural analgesia applied on 50 patients chosen at random in a group of 90 after thoracotomy is reported. METHODS: At the end of operation a peridural catheter for continuative infusion was applied in the paravertebral socket by direct transfixion of chest wall. A local anaesthetic has been given (75 mg of bupivacaine 0.50%) through the catheter at 8 hours interval for three times at the most. The degree of analgesia has been valued immediately before and after medicine administration and during the 8 hours interval by recording the cardiocirculatory and haemogasanalytical parameters. The measurement of pain intensity has been achieved by visual analogous just an hour after operation and subsequently every 4 hours during the first post operative day and every 8 hours during the following days. RESULTS: Most of the examined patients (90%), reported a remarkable attenuation of pain, valued by achromatic grey test after 4 hours since the first giving. The catheter has always been removed during the 8th postoperative day and it did not cause intrapleural complications. The method used warrants a good level of analgesia, improving the respiratory per-formance and giving a rapid mobilization, essential items in the reduction of immediate post operative complications. CONCLUSIONS: The results confirm the validity of this treatment in the pain control of thoracothomized patients with a positive answer in 45 out of 50 examined patients without remarkable complications.     

Epidemiologic evaluation of postoperative wound infections in dogs and cats

OBJECTIVE: To determine postoperative wound infection rates in dogs and cats for various wound contamination categories and to identify factors that influence postoperative wound infection rates. DESIGN: Epidemiologic study. SAMPLE POPULATION: 1,574 wounds in 1,255 dogs and cats. PROCEDURE: Information recorded included signalment, nutritional status, surgery duration, surgical procedures, wound contamination classification, interval from clipping until surgery, blood pressure values, active infection at a distant site, endocrinopathy, and administration of immunosuppressive medications or antibiotics. Relative risk, 95% confidence intervals, and multiple regression analyses were performed. RESULTS: Postoperative infection was evident in 86 of 1,574 (5.5%) wounds, including 54 of 1,146(4.7%) and 13 of 259 (5.0%) animals with clean and clean-contaminated wounds respectively, and 12 of 100 (12.0%) and 7 of 69 (10.1%) animals with contaminated and dirty wounds, respectively. Animals with clean wounds that received antibiotics other than as prescribed in our perioperative protocol had a higher infection rate than animals that did not receive antibiotics. Surgical sites clipped before anesthetic induction were 3 times more likely to become infected than sites clipped after induction. Risk of wound infection increased with increasing duration of surgery. CLINICAL IMPLICATIONS: Wound contamination categories had too much variation to make them useful for predicting animals that would develop wound infections. Surgical sites should be clipped immediately prior to surgery, and intraoperative time should be kept to a minimum. Unless indicated for other current active infection, prolonged use of antibiotics after surgery should be avoided in animals with clean wounds.     

Decrease in isoflurane requirements and of postoperative pain with preanesthetic intrathecal morphine

OBJECTIVES: 1) To determine whether preanesthetic intrathecal administration of 0.5 mg morphine reduces isoflurane requirements for anesthetic maintenance. 2) To assess the duration of postoperative analgesia and the type and frequency of complications attributable to the procedure. PATIENTS AND METHODS: A series of 45 adults were distributed into 3 groups of 15 patients each based on site of surgery and site of preanesthetic (30 min) injection of 0.5 mg pure morphine. Control group (C0) patients underwent lumbar surgery and received subcutaneous morphine. Group C0.5 patients also underwent lumbar surgery but received intrathecal morphine. Group A0.5 patients underwent long-duration high abdominal surgery and received intrathecal morphine. Anesthesia was maintained with nitrous oxide (60%) in oxygen (40%) and a variable concentration of isoflurane. Isoflurane needs were assessed by averaging six consecutive measurements of end-tidal isoflurane pressure (M30FETiso) taken at intervals of 5 min. Postoperative analgesia was evaluated by means of a visual analog scale that was converted to numerical units (VASn). RESULTS: M30FETiso in group C0 (0.8%) was always higher (p < 0.01) than in the other two groups. M30FETiso in group A0.5 was higher (p < 0.01) than in group C0.5 during the first 150 min of surgery. After 180 min, there were no differences in M30FETiso (0.10-0.16%) between the two groups receiving intrathecal morphine. VASn results (mean +/- SD) in the first 4 hours were higher in group C0 (7.33 +/- 0.6) than in group C0.5 (1.13 +/- 0.35) and group A0.5 (1.07 +/- 0.26). The time of morphine-dependent analgesia was shorter (p < 0.01) in group C0 (0.62 +/- 0.38 hours) than in groups C0.5 (30.4 +/- 5.11 hours) and A0.5 (28 +/- 4.34 hours). There were no significant differences between the two groups receiving intrathecal morphine. CONCLUSIONS: Preanesthetic subarachnoid lumbar injection of 0.5 mg of pure morphine reduced early requirements for isoflurane in lumbar surgery (0.14% after 60 min). This reduction was initially less in patients undergoing abdominal surgery (0.44% at 60 min) but was the same after 150 min. Postoperative analgesia was long-term and independent of type or duration of surgery. There was no respiratory depression after surgery and the incidence of postoperative complications was similar in the two groups that received subarachnoid morphine.     

Management of postoperative pain in surgical units

In order to improve the management of postoperative pain many publications insist on progressive changes in care organization. The following list outlines steps to be taken for implementation of these changes: 1) an initial analysis of management of post-operative pain allows awareness of reforms to be proposed; 2) participation of health teams in special training in order to use evaluation tools and collect data (use of analgesics, adverse effects); 3) establishing policies and procedures: recovery room, guidelines for analgesic use and adverse effects; 4) notifying patient about the various procedures to be used in postoperative period--discussion with the patient during the preoperative interview; 5) current use of standard patient-controlled analgesia (PCA) and locoregional analgesia; 6) use of combined techniques in order to achieve a balanced analgesia; 7) implementing a quality assurance programme which should include analgesic effectiveness, patient satisfaction and prevention of complications; and 8) planning of an Acute Pain Service based on a clinical nurse co-ordinator which offers highly effective forms of postsurgical analgesia.     

Premedication with oral dextromethorphan reduces postoperative pain after tonsillectomy

The aim of the present study was to examine whether premedication with dextromethorphan, a clinically available N-methyl-D-aspartic acid (NMDA) receptor antagonist, could reduce postoperative pain after tonsillectomy. Thirty-six patients scheduled for elective bilateral tonsillectomy were investigated in a double-blinded, randomized study. The patients were randomly assigned to one of three groups: control, dextromethorphan 30 mg (Dex 30), and dextromethorphan 45 mg (Dex 45) groups. In the control group, premedication was with oral placebo and intramuscular (i.m.) midazolam and atropine. In the Dex 30 and Dex 45 groups, patients were premedicated with i.m. midazolam and atropine and oral dextromethorphan 30 mg and 45 mg, respectively. Pain was evaluated repeatedly throughout 7 postoperative days, at rest and on swallowing, using a self-rating visual analog scale (VAS). The total doses of analgesics administered postoperatively were also recorded. The Dex 45 group showed significantly lower VAS scores than the control group both at rest and on swallowing throughout the 7 days. The total doses of postoperative analgesics in the Dex 45 group were significantly less than those in the control group. The Dex 30 group showed significantly lower VAS scores than the control group at rest, but not on swallowing. These results indicate that premedication with Dex 45 reduces postoperative pain after tonsillectomy, not only at rest but on swallowing. IMPLICATIONS: Recently, it has been suggested that central sensitization caused by the activation of N-methyl-D-aspartic acid receptors may contribute to the postoperative pain. We found that premedication with 45 mg of dextromethorphan, a clinically available N-methyl-D-aspartic acid receptor antagonist, reduced postoperative pain after tonsillectomy.     

Toxoplasma lymphadenitis. Analysis of cytologic and histopathologic criteria and correlation with serologic tests

Fear reactions of rats given bilateral lesions to the septum, hippocampus, or amygdala were compared with those of rats given sham lesions, in 2 animal models of anxiety: the shock-probe burying test and the elevated plus-maze test. Septal lesions produced anxiolytic effects in both tests (i.e., an increase in open-arm activity and a decrease in burying), whereas hippocampal and amygdaloid lesions produced neither of these effects. On the other hand, hippocampal and amygdaloid lesions impaired rats' passive avoidance of the electrified shock-probe, whereas septal lesions did not. These dissociations suggest that limbic structures such as the septum, amygdala, and hippocampus exert parallel but distinct control over different fear reactions.     

Psychosocial predictors of children's postoperative pain

The purpose of this study was to investigate the influence of psychosocial variables in the prediction of children's pain intensity following surgery. Forty-two children, ages 7 to 17 years (M = 12.26, SD = 3.06), completed an interview 1 week prior to surgery assessing anticipatory distress related to their forthcoming surgery and history of coping strategy use. Following surgery, children reported the intensity of their pain using visual analog scales. Findings demonstrated that the majority of children experienced moderate to severe postoperative pain. Hierarchical multiple regression analyses revealed that psychosocial variables added to the prediction of children's postoperative pain after controlling for the influence of surgery-related and demographic variables. These findings lend initial support for the inclusion of psychosocial assessment measures (e.g., anticipatory surgery distress) in the preoperative assessment of pediatric patients who may be at risk for excessive postsurgical pain.     

The impact of postoperative pain on the development of postoperative delirium

We performed a prospective observational study to examine the role of postoperative pain and its treatment on the development of postoperative delirium. Pain was measured in direct patient interviews using a visual analog scale (VAS) and was assessed for pain at rest, pain with movement, and maximal pain over the previous 24 h. Postoperative delirium was diagnosed during these interviews by using the confusion assessment method (CAM) and/or by using data from the medical record and the hospital's nursing intensity index. The method of postoperative analgesia, type of opioid, and cumulative opioid dose were also recorded. After controlling for known preoperative risk factors for delirium (age, alcohol abuse, cognitive function, physical function, serum chemistries, and type of surgery), higher pain scores at rest was associated with an increased risk of delirium over the first 3 postoperative days (adjusted risk ratio 1.20, P = 0.04). Pain with movement and maximal pain were not associated with delirium. Method of postoperative analgesia, type of opioid, and cumulative opioid dose were not associated with an increased risk of delirium. We conclude that more effective control of postoperative pain reduces the incidence of postoperative delirium. Implications: We performed daily interviews in a large population of patients undergoing noncardiac surgery to measure their level of pain and development of delirium. We found an association between higher pain levels at rest and the development of delirium. Our results suggest that better control of postoperative pain may reduce this serious complication.     

Effectiveness of documented assessment of postoperative pain

Documented assessment of pain does increase patient satisfaction in pain control and treatment but it must be carried out regularly and, more importantly, it must be acted upon. Patients who participate in documented assessment of pain postoperatively may find it easier to communicate their pain levels to the nurse, may feel more informed about their treatment and may be given analgesia more quickly than a control group. Nurses are aware of the importance of pain intensity assessment but do not always assess the effectiveness of the analgesia given. Each individual's perception of pain is unique and the desired amount of relief from pain is infinitely variable. Pain cannot be treated or controlled if it is not accurately assessed. Any information given before surgery decreases anxiety levels and therefore lessens the patient's perception of pain postoperatively, particularly when the information is related to how and where the patient may feel pain. The use of documented pain assessment combined with patient-controlled analgesia systems may be the key to effective postoperative pain control.     

Safety assessment of postoperative pain management by an acute pain service

The purpose of this study was to evaluate the synthetic retinoids isotretinoin and etretinate to treat dogs with intracutaneous cornifying epitheliomas (ICE), other benign skin neoplasias, and cutaneous lymphoma. Twenty-four dogs were used. All tumors were diagnosed by histologic examination. Ten dogs with multiple (at least 5) benign skin tumors (7 with ICE, 1 each with inverted papillomas, sebaceous adenomas and epidermal cysts) were treated with isotretinoin (n = 7) and/or etretinate (n = 5). Twelve dogs with cutaneous lymphoma were treated with isotretinoin, and 2 dogs with cutaneous lymphoma were initially treated with etretinate. Successful treatment with isotretinoin was achieved in 1 dog with ICE, 1 with inverted papillomas, and 1 with epidermal cysts. Partial improvement with isotretinoin was seen in 2 dogs with ICE. Successful treatment was achieved with etretinate in 4 dogs with ICE (Norwegian Elkhound was the predominant breed with ICE). Remission was achieved in 6 of the 14 dogs with cutaneous lymphoma. Adverse effects developed in 7 of the 24 dogs, so treatment was stopped in 2 dogs.     

The problem of acute pain in postoperative period]

The problem of postoperative pain remains actual despite the existence of a variety of pharmaceutical and nonpharmaceutical methods of anesthesia. Acute postoperative pain is an essential component of the surgical stress syndrome. Opioid analgetics (Buprenorfin, Nubain, Tramal, Promedol, Morphine) take the leading position among other types of analgetics. Present-day individual approach to administration of analgetics is still imperfect. The use of a standard dose of analgetics appears to be inadequate in a number of patients. The increase of opioids dose may lead to adverse reactions. In view of this it is valid to use nonsteroid antinflammatory medicines (Ketorolac). The choice of a proper dose of an analgetic is critically important in achieving adequate anesthesia. Patient-controlled analgesia (PCA) or "analgesia on demand" is an alternative to administration of analgetics. The major advantage of PCA is the opportunity to achieve the rate of analgesia, according to individual demand of a patient. Besides, PCA allows to reach the desired effect much faster and to maintain the stable plasma level of an analgetic. 2-year experience of the PCA use in more than 200 patients of the National Research Centre for Surgery ICU has been analysed. The authors advocate use of PCA in clinical practice.     

Altered electrodermal responsivity associated with clinical pain

We used certain physiologic maneuvers to perturb the autonomic nervous system (ANS) in an attempt to detect a link between the ANS and pain. In the unperturbed state, we found no difference in the electrodermal response among normal controls, preoperative patients (increased stress without pain) and postoperative patients (increased stress and pain). The electrodermal response elicited by autonomic maneuvers was significantly attenuated in postoperative patients but not in preoperative patients or in normal control subjects.     

Thalamic pain syndrome: anatomic and metabolic correlation

The reinnervation of cutaneous targets was studied in the rat tail after proximal lesions of all collector nerves. The distribution of immunofluorescent nerve fibres stained for calcitonin-gene-related peptide (CGRP) and substance P (SP) was examined after 110-210 days. Targets at all sites were reinnervated by CGRP-immunoreactive (IR) fibres. However, SP-IR terminals were rare, particularly distally, despite staining within subdermal nerve trunks.     

Hypnosis and clinical pain.

Hypnosis has been demonstrated to reduce analogue pain, and studies on the mechanisms of laboratory pain reduction have provided useful applications to clinical populations. Studies showing central nervous system activity during hypnotic procedures offer preliminary information concerning possible physiological mechanisms of hypnotic analgesia. Randomized controlled studies with clinical populations indicate that hypnosis has a reliable and significant impact on acute procedural pain and chronic pain conditions, Methodological issues of this body of research are discussed, as are methods to better integrate hypnosis into comprehensive pain treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)