Persistent pain following knee arthroplasty.

BACKGROUND AND OBJECTIVE: The prevalence of persistent pain after orthopaedic surgery has been the subject of only few studies and the risk factors for persistent pain have been evaluated even more rarely. The purpose of the present study was to evaluate the degree and the risk factors of persistent pain after knee arthroplasty. METHODS: The prevalence of persistent postoperative pain after knee replacement was evaluated with a questionnaire in a large, register-based cross-sectional prevalence study. The main hypothesis was that the type of operation (primary, bilateral, revision) would influence the prevalence of persistent postoperative pain. Logistic regression analysis was performed to test the hypothesis and to find other possible risk factors for the development of persistent pain. RESULTS: The total number of patients was 855. The operation was a primary arthroplasty in 648 patients (75.7%), a bilateral arthroplasty in 137 patients (21.1%) and a revision arthroplasty in 70 patients (8.2%). The response rate was 65.7%. The type of operation was not associated with the prevalence of persistent pain, but the degree of early postoperative pain was the strongest risk factor. If the degree of pain during the first postoperative week was from moderate to intolerable, the risk for the development of persistent pain was three to 10 times higher compared with patients complaining of mild pain during the same period. Other risk factors were the long duration of preoperative pain and female sex. CONCLUSION: Intensity of early postoperative pain and delayed surgery increase the risk of the persistent pain after knee arthroplasty.

The effect of parecoxib on kidney function at laparoscopic hysterectomy.

Conventional nonsteroidal anti-inflammatory drugs (NSAIDs) have a well-documented nephrotoxic action. Still, there are only few studies that have investigated the nephrotoxicity of cyclo-oxycenase-2-inhibitors during the perioperative period. Thirty patients scheduled for elective laparoscopic hysterectomy were enrolled in this prospective, randomized double-blind study. Patients were randomized into two groups: a saline-treated control group (placebo) and 80 mg parecoxib-treated group (parecoxib). The samples for the analyses of serum and urine were collected at the induction of anesthesia, two hours thereafter, two hours from the end of anesthesia, and on the first postoperative day (POD). S-crea, S-urea, S-cystatin C, S-Na, S-K, U-1mikroglobulin/U-crea, U-GST/U-crea, and U-GST/U-crea were analyzed from the samples. Urine output was measured every hour for the first five hours, and total amount of urine was measured until the first postoperative day. There were no clinical and few statistical significant differences between the two groups in the renal measurements during the study period. The urinary output was also similar in the two groups. A single dose of 80 mg of parecoxib was well tolerated by the kidneys in the short-term perioperative use in patients undergoing laparoscopic hysterectomy with ASA physiological status I-II and age under 60 years.

Peripherally administered sufentanil inhibits pain perception after postpartum tubal ligation.

The clinical effectiveness of locally administered opioids is still under discussion; in particular, the potency of morphine in settings other than intra-articular arthroscopy has been questioned. We developed another pain model, postpartum resection of the fallopian tubes for sterilisation, in which each patient serves as her own control when one side is infiltrated with the active drug (in this study sufentanil 5 mg) and the contralateral side with normal saline. In the control group both sides are infiltrated with plain saline. After 30 min from the end of anaesthesia onwards, 26 out of 30 patients observed significant pain relief on the side of the sufentanil infiltration, which in 11 patients lasted until the end of the observation period 24 h postoperatively; no difference was observed in the control group. In our pain model with a high assay sensitivity, the infiltration of one side with the lipophilic test drug, sufentanil, caused local analgesia in primarily non-inflamed tissue. The use of each patient as her own control excluded inter-subject bias.

Gabapentin for the prevention of postoperative pain after vaginal hysterectomy.

Gabapentin alleviates and/or prevents acute nociceptive and inflammatory pain both in animals and volunteers, especially when given before trauma. Gabapentin might also reduce postoperative pain. To test the hypothesis that gabapentin reduces the postoperative need for additional pain treatment (postoperative opioid sparing effect of gabapentin in humans), we gave 1200 mg of gabapentin or 15 mg of oxazepam (active placebo) 2.5 h prior to induction of anaesthesia to patients undergoing elective vaginal hysterectomy in an active placebo-controlled, double blind, randomised study. Gabapentin reduced the need for additional postoperative pain treatment (PCA boluses of 50 microg of fentanyl) by 40% during the first 20 postoperative hours. During the first 2 postoperative hours pain scores at rest and worst pain score (VAS 0-100 mm) were significantly higher in the active placebo group compared to the gabapentin-treated patients. Additionally, pretreatment with gabapentin reduced the degree of postoperative nausea and incidence of vomiting/retching possibly either due to the diminished need for postoperative pain treatment with opioids or because of an anti-emetic effect of gabapentin itself. No preoperative differences between the two groups were encountered with respect to the side effects of the premedication. However, 15 mg oxazepam was more effective in relieving preoperative anxiety than 1200 mg gabapentin.

Using the nonlinear control of anaesthesia-induced hypersensitivity of EEG at burst suppression level to test the effects of radiofrequency radiation on brain function.

BACKGROUND: In this study, investigating the effects of mobile phone radiation on test animals, eleven pigs were anaesthetised to the level where burst-suppression pattern appears in the electroencephalogram (EEG). At this level of anaesthesia both human subjects and animals show high sensitivity to external stimuli which produce EEG bursts during suppression. The burst-suppression phenomenon represents a nonlinear control system, where low-amplitude EEG abruptly switches to very high amplitude bursts. This switching can be triggered by very minor stimuli and the phenomenon has been described as hypersensitivity. To test if also radio frequency (RF) stimulation can trigger this nonlinear control, the animals were exposed to pulse modulated signal of a GSM mobile phone at 890 MHz. In the first phase of the experiment electromagnetic field (EMF) stimulation was randomly switched on and off and the relation between EEG bursts and EMF stimulation onsets and endpoints were studied. In the second phase a continuous RF stimulation at 31 W/kg was applied for 10 minutes. The ECG, the EEG, and the subcutaneous temperature were recorded. RESULTS: No correlation between the exposure and the EEG burst occurrences was observed in phase I measurements. No significant changes were observed in the EEG activity of the pigs during phase II measurements although several EEG signal analysis methods were applied. The temperature measured subcutaneously from the pigs' head increased by 1.6 degrees C and the heart rate by 14.2 bpm on the average during the 10 min exposure periods. CONCLUSION: The hypothesis that RF radiation would produce sensory stimulation of somatosensory, auditory or visual system or directly affect the brain so as to produce EEG bursts during suppression was not confirmed.

Children's drawings as a measure of anxiety level: a clinical pilot study.

BACKGROUND: No simple method exists to distinguish children in need for premedication. The present study was planned to detect preoperative anxiety levels of children by rating their drawings. METHODS: Sixty ASA I children aged 4-7 years undergoing adenoidectomy were divided into AGIT and CALM groups according to agitation level observed during venous cannulation. All children drew a picture at three different times: (i) just after arrival in the day-case unit, (ii) 10 min before operation and, (iii) prior to leaving for home. The children were also randomized to three premedication groups: group D, rectal diazepam 0.5 mg x kg(-1); group P, 0.9% NaCl 0.1 ml x kg(-1) rectally; group NT, no premedication. Five features (size of the drawing, form of the drawing line, colors used, mark of the pen and clarity of the picture) from the children's drawings were rated with a 3-point scale. The ratings of each feature were made to form a sum score of anxiety ranging from 0 to 10. In the analysis of variance for repeated measures both the premedication group and agitation score were taken into the model as factors. RESULTS: The anxiety score of the drawings of the agitated children (during venous cannulation) was significantly higher already after arrival in the hospital [AGIT 4.76 (95% CI: 3.56-5.96) Vs CALM 3.67 (95% CI: 2.97-4.37) P = 0.029], but there were no statistical differences between the different premedication groups. CONCLUSIONS: When routine sedative premedication is not used the drawings of the children might detect the children needing sedative premedication.