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Biomedical subjects

Oliver H G Wilder-Smith

Publications and source records attributed to Oliver H G Wilder-Smith.

10 recordsLinked to original sources
PubMed2006

Outcome of transcutaneous electrical nerve stimulation in chronic pain: short-term results of a double-blind, randomised, placebo-controlled trial.

The aim of this study was to test the efficacy of shortterm transcutaneous electrical nerve stimulation (TENS) treatment in chronic pain with respect to pain intensity and patients' satisfaction with treatment results. We therefore performed a randomised controlled trial comparing TENS and sham TENS. Patients, researchers and therapists were blinded for treatment allocation. One hundred and sixty-three patients with chronic pain referred to the Pain Centre entered the study. Conventional TENS and sham TENS were applied in the segments of pain, for a period of ten days. Outcome measures were pain intensity (visual analogue scale) and patients' satisfaction with treatment result (yes or no). The proportions of patients satisfied with treatment result differed significantly for TENS compared to sham TENS (58 and 42.7% respectively, chi(2)=3.8, p=0.05). However, no differences in pain intensity were found for patients treated with TENS or sham TENS. Only for patients satisfied with treatment results pain intensity gradually decrease equally both for TENS and sham TENS with repeated treatment application.

Adult↗
PubMed2005

Impairments as measured by ISS do not greatly change between one and eight years after CRPS 1 diagnosis.

BACKGROUND: Complex Regional Pain Syndrome type 1 (CRPS 1) is a potentially incapacitating complication in which pain seems to be the most disabling factor. We performed a late follow up study of a well-defined CRPS 1 population more than eight years after diagnosis. The relationships between early and late impairments were studied with a view to outcome prediction and to investigate possible differences in long-term impairments according to initial CRPS 1 subdiagnosis (i.e. "warm" or "cold", diagnosed according to skin temperature measured via infrared thermometer). METHODS: We again measured patients using the Impairment Level SumScore (ISS) (T8). These data were compared with earlier ISS measurements at CRPS diagnosis (T0) and after one year's treatment (T1). Correlations were determined between these measures. RESULTS: Forty-five patients participated in the present study. Total median ISS improved by 55% (statistically/clinically significant) after one year's treatment (T1), and worsened (non-significantly) by 14% from T1 to T8 - without differences according to original subdiagnosis. ISS correlations were stronger for T1 vs. T8 than for T0 vs. T1 or T0 vs. T8, being strongest for the ISS factors related to pain. CONCLUSIONS: Considerable impairments, as measured by ISS, are still present over eight years after first CRPS 1 diagnosis. These do not greatly change between one and eight years post-diagnosis. ISS outcomes are similar for "cold" and "warm" CRPS 1 diagnostic subgroups. Component ISS scores associated with pain appear to possess greatest predictive power.

Adult↗
PubMed2005

Chronic pancreatitis patients show hyperalgesia of central origin: a pilot study.

BACKGROUND: The pain of chronic pancreatitis remains challenging to manage, with treatment all too often being unsuccessful. A main reason for this is lacking understanding of underlying mechanisms of chronic pain in these patients. AIM: To document, using somatic quantitative sensory testing, changes in central nervous system processing (neuroplasticity) associated with chronic pancreatitis pain and thus gain insight into underlying pain mechanisms. PATIENTS AND METHODS: We studied 10 chronic pancreatitis patients on stable opioid analgesic medication. Ten matched surgical patients without pain served as controls. Pain verbal numeric rating scores (NRS) and thresholds to electric skin stimulation and pressure pain were measured in dermatomes T10 (pancreatic area), C5, T4, L1 and L4. RESULTS: The pancreatitis patients had a median NRS pain score of 5 (range 3-8). Electric sensation and pain thresholds were significantly increased in the pancreatic region, tending to be more so in female pancreatitis patients. Pressure pain thresholds were significantly lower in pancreatitis patients than in controls, with men tending towards greater generalised relative hyperalgesia than women. CONCLUSIONS: Chronic pancreatitis patients show pronounced generalised deep hyperalgesia that is present despite opioid therapy. These signs, consistent with central sensitisation, appear relatively more prominent in men than women. There is also evidence suggesting that women may have a better segmental inhibitory response than men, possibly explaining their relatively less prominent generalised deep tissue hyperalgesia compared to men.

Adult↗
PubMed2005

Opioid use in the elderly.

Pain treatment in the elderly is an important challenge to Western societies due to increasing numbers of old persons, their higher incidence of pain, and their greater susceptibility to adverse effects of pain medication. We provide an overview of the factors liable to influence opioid action in the elderly population. A major challenge for the physician prescribing opioids in the elderly is their greater risk of medication-associated problems. Thus, older patients suffer increased vulnerability to adverse drug effects and interactions, higher rates of polypharmacy, and more comorbidity. These problems are compounded by a relative lack of definitive published information. There is clearly a need for more research in this area. Aging affects opioid pharmacokinetics via altered body composition (distribution volumes) and organ function (liver=metabolism, kidney=excretion). Pharmacodynamics is affected via impaired neurotransmitter/peptide production and changed receptor affinities/populations. Older women may need less morphine analgesia postoperatively, while pain sensitivity tends to increase particularly in older men. However, the net effects of changes in opioid pharmacology with age on clinical opioid analgesia remain unclear, probably due to the significantly greater variability in body function with increasing age. Practical recommendations for opioid prescription in the elderly include meticulous review of indication for opioid use, not only initially but also at regular intervals thereafter. A policy of careful titration should be followed, with conservative choice of dosage on starting. Dosing intervals may need to be lengthened subsequently. Finally, it should be remembered that old persons do not necessarily need less opioid than younger ones.

Aged↗
PubMed2005

Patients initially diagnosed as 'warm' or 'cold' CRPS 1 show differences in central sensory processing some eight years after diagnosis: a quantitative sensory testing study.

We used quantitative sensory testing (QST) to gain further insight into mechanisms underlying pain in CRPS 1. Specific goals were: (1) to identify altered patterns of sensory processing some 8 years after diagnosis, (2) to document differences in sensory processing between 'warm' and 'cold' diagnostic subgroups, (3) to determine relationships between changed sensory processing and disease progression regarding pain. The study was performed on a cohort of patients (n=47) clinically diagnosed with CRPS 1 of one upper extremity approximately 8 years previously. Pain was quantified by VAS and MacGill Pain Questionnaire (MPQ), and all subjects underwent electrical and mechanical QST. Cold patients (n=13) had poorer MPQ scores than warm ones (n=34), and more pain on electrical stimulation. Their evoked pain increased with disease progression and correlated with clinical pain measures. For both diagnostic subgroups, thresholds to pressure pain were lower on the affected extremity and with disease progression. Eight years after original diagnosis, cold CRPS 1 patients have poorer clinical pain outcomes and show persistent signs of central sensitisation correlating with disease progression. The latter is not the case for warm CRPS 1 patients. Both diagnostic subgroups show greater pressure hyperalgesia on the affected limb and with disease progression. QST may prove useful in the subdiagnosis of CRPS 1 and in quantifying its progression, with both applications warranting further investigation for clinical and research use.

Cold Temperature↗
PubMed2003

Quantitative sensory testing and human surgery: effects of analgesic management on postoperative neuroplasticity.

BACKGROUND: Altered central nervous system sensory processing (neuroplasticity) is a basic mechanism underlying postoperative pain that can be made visible using quantitative sensory testing. Using quantitative sensory testing, the authors investigated how perioperative analgesia affects postoperative neuroplasticity and how this relates to clinical pain measures. METHODS: Patients undergoing back surgery received placebo, fentanyl, or ketorolac (n = 15 per group) before isoflurane-nitrous oxide anesthesia. Preoperatively to 5 days postoperatively, we measured thresholds to electrical skin stimulation at the incision site, arm, and leg; pain scores; and morphine patient-controlled analgesia consumption. RESULTS: Decreased pain thresholds versus preoperatively were seen 5 days postoperatively, with decreases greater for ketorolac (-63%; P = 0.00005 vs. preoperatively) than placebo (-45%; P = 0.008 vs. preoperatively) but nonsignificant for fentanyl (-36%; P = 0.9 vs. preoperatively). Mainly nonnociceptive thresholds were increased up to 24 h postoperatively. Postoperative clinical pain measures were similar across drug groups. Postoperative pain tolerance threshold changes did not correlate with preoperative clinical pain measures but were inversely related to preoperative thresholds for placebo and ketorolac but not fentanyl. CONCLUSIONS: Without analgesia, neuroplasticity after surgery was inhibitory the first 24 h and followed at 5 days by excitation. Fentanyl efficiently preempted this hyperalgesia, but hyperalgesia was greater with ketorolac than with placebo. Clinical pain measures neither reflected the different effects of ketorolac and fentanyl on postoperative neuroplasticity nor permitted prediction of postoperative neuroplasticity. The information obtained by perioperative quantitative sensory testing is separate from and additional to that from clinical pain measures and may enable more mechanism-based approaches to surgical analgesia management in the future.

Anesthesia, General↗
PubMed2002

Preoperative back pain is associated with diverse manifestations of central neuroplasticity.

Increased or decreased gain in central nervous system processing after surgery, i.e. neuroplasticity, may play an important role in postoperative pain. Identification of patient subgroups particularly vulnerable to either type of post-surgical neuroplasticity is thus of interest. Preoperative pain has also been suggested to increase vulnerability to post-surgical chronic pain complications due to central facilitation. To study if back pain preoperatively is associated with differences in central sensory processing, we measured transcutaneous electric sensation, pain detection and pain tolerance thresholds at the upper arm, lower back and lower leg in 52 consecutive patients scheduled for back surgery in a blinded, prospective fashion. Patients with no pain had significantly lower pain thresholds than patients with pain in the leg, and significantly higher pain thresholds than those with pain in the back. These results suggest that preoperative pain can induce diverse central neuroplastic changes, i.e. inhibition and facilitation, and that the nature of this neuroplasticity depends on the nature of the pain involved. The presence of facilitation may be the basis of the increased vulnerability described in some studies of patients with significant preoperative pain, whereas the implications of reduced pain sensitivity are less clear. The demonstration of neuroplasticity and its diversity are, however, likely to be of significant clinical relevance.

Adult↗
PubMed2002

Acute pain management after surgery or in the emergency room in Switzerland: a comparative survey of Swiss anaesthesiologists and surgeons.

The treatment of acute pain remains unsatisfactory despite advances in pain research and the publication of numerous guidelines. The aim of this study was to survey postoperative and emergency room acute pain treatment in Switzerland, particularly regarding compliance with practice guidelines on therapeutic responsibility, treatment algorithms, pain documentation, quality control and education.A representative sample of anaesthesiologists and surgeons (general and orthopaedic) was selected from all Swiss hospitals with regular surgical activity and sent a 256 point questionnaire on acute pain management. Five hundred and seventy five doctors were contacted in 98 hospitals, 44% of doctors (covering 89% of hospitals) returned fully completed questionnaires. Half the respondents work in a hospital with an acute pain service. For postoperative pain management, only 10% of prescription is by algorithm, less than a third of respondents regularly determine pain scores, only 15% perform any statistical analysis of pain management, less than one third regularly meet to discuss management problems, and half claim not to have received-or be receiving-formal (i.e. structured/accredited) pain education. The situation is even less satisfactory for emergency room analgesia. Respondents accept the contribution of postoperative and emergency room analgesia to reduced costs and improved medical outcomes. Asked to highlight their major concerns in acute pain management, lack of education and inadequate organisation are listed in first and second positions. This survey suggests that compliance with published practice guidelines for acute pain management can be improved, and highlights the need for continuing organisational and educational development in acute analgesia, particularly for the emergency room.

Acute Disease↗