A Novel Photoplethysmography Sensor for Vital Signs Monitoring from the Human Trachea.

Current pulse oximeter sensors can be challenged in working accurately and continuously in situations of reduced periphery perfusion, especially among anaesthetised patients. A novel tracheal photoplethysmography (PPG) sensor has been developed in an effort to address the limitations of current pulse oximeters. The sensor has been designed to estimate oxygen saturation (SpO2) and pulse rate, and has been manufactured on a flexible printed circuit board (PCB) that can adhere to a standard endotracheal (ET) tube. A pilot clinical trial was carried out as a feasibility study on 10 anaesthetised patients. Good quality PPGs from the trachea were acquired at red and infrared wavelengths in all patients. The mean SpO2 reading for the ET tube was 97.1% (SD 1.0%) vs. the clinical monitor at 98.7% (SD 0.7%). The mean pulse rate for the ET sensor was 65.4 bpm (SD 10.0 bpm) vs. the clinical monitor at 64.7 bpm (SD 9.9 bpm). This study supports the hypothesis that the human trachea could be a suitable monitoring site of SpO2 and other physiological parameters, at times where the periphery circulation might be compromised.

A pilot study investigating whether quantitative sensory testing alters after treatment in patients with fibromyalgia.

BACKGROUND: Fibromyalgia is a chronic musculoskeletal pain condition that is often associated with sleep disturbances and fatigue. The pathophysiology of fibromyalgia is not understood, but indirect evidence suggests a central dysfunction of the nociceptive modulating system. The aim of this study was to evaluate whether quantitative sensory testing detects a change in pain thresholds in fibromyalgia patient receiving pregabalin treatment. METHODS: A total of 25 patients were recruited for the study and received routine pregabalin, but only 14 patients completed the treatment. Assessment of pressure pain thresholds and changes in conditioned pain modulation using ischaemic pain as a conditioning stimulus were measured at baseline and every 4 weeks for 12 weeks. Fibromyalgia impact questionnaire, PainDETECT and SF-12 were also completed. RESULTS: Patients with fibromyalgia demonstrated a less-efficient conditioned pain modulation at baseline. An efficient conditioned pain modulation was observed at 1 month and this was maintained until the final visit. Pressure pain thresholds (PPTs) showed a significant improvement from baseline. Patients also reported a similar magnitude of improvements in PainDETECT, fibromyalgia impact questionnaire (FIQ) and its impact on daily life and change in outcome for SF-12. CONCLUSION: This pilot study reports an increase in PPTs and improved conditioned pain modulation response after commencing pregabalin, which was maintained at 12 weeks, and this was supported by positive pain scores. Pregabalin is a licenced treatment for fibromyalgia in Europe, and its response to central sensitisation, particularly 'dynamic responses', has not been reported. We conclude that pregabalin has the potential to reduce peripheral and central sensitisation in patients with fibromyalgia, as measured using quantitative sensory testing.

Facet-joint injections for non-specific low back pain: a feasibility RCT.

BACKGROUND: Pain of lumbar facet-joint origin is a common cause of low back pain in adults and may lead to chronic pain and disability, with associated health and socioeconomic implications. The socioeconomic burden includes an inability to return to work resulting in loss of productivity in addition to direct and indirect health-care utilisation costs. Lumbar facet-joints are paired synovial joints between the superior and inferior articular processes of consecutive lumbar vertebrae and between the fifth lumbar vertebra and the sacrum. Facet-joint pain is defined as pain that arises from any structure that is part of the facet-joints, including the fibrous capsule, synovial membrane, hyaline cartilage and bone. This pain may be treated by intra-articular injections with local anaesthetic and steroid, although this treatment is not standardised. At present, there is no definitive research to support the use of targeted lumbar facet-joint injections to manage this pain. Because of the lack of high-quality, robust clinical evidence, the National Institute for Health and Care Excellence (NICE) guidelines on the management of chronic low back pain [NICE. Low Back Pain in Adults: Early Management. Clinical guideline (CG88). London: NICE; 2009] did not recommend the use of spinal injections despite their perceived potential to reduce pain intensity and improve rehabilitation, with NICE calling for further research to be undertaken. The updated guidelines [NICE. Low Back Pain and Sciatica in Over 16s: Assessment and Management. NICE guideline (NG59). London: NICE; 2016] again do not recommend the use of spinal injections. OBJECTIVES: To assess the feasibility of carrying out a definitive study to evaluate the clinical effectiveness and cost-effectiveness of lumbar facet-joint injections compared with a sham procedure in patients with non-specific low back pain of > 3 months' duration. DESIGN: Blinded parallel two-arm pilot randomised controlled trial. SETTING: Initially planned as a multicentre study involving three NHS trusts in the UK, recruitment took place in the pain and spinal orthopaedic clinics at Barts Health NHS Trust only. PARTICIPANTS: Adult patients referred by their GP to the specialist clinics with non-specific low back pain of at least 3 months' duration despite NICE-recommended best non-invasive care (education and one of a physical exercise programme, acupuncture or manual therapy). Patients who had already received lumbar facet-joint injections or who had had previous back surgery were excluded. INTERVENTIONS: Participants who had a positive result following a diagnostic test (single medial branch nerve blocks) were randomised and blinded to receive either intra-articular lumbar facet-joint injections with steroids (intervention group) or a sham procedure (control group). All participants were invited to attend a group-based combined physical and psychological (CPP) programme. MAIN OUTCOME MEASURES: In addition to the primary outcome of feasibility, questionnaires were used to assess a range of pain-related (including the Brief Pain Inventory and Short-Form McGill Pain Questionnaire version 2) and disability-related (including the EuroQol-5 Dimensions five-level version and Oswestry Low Back Pain Questionnaire) issues. Health-care utilisation and cost data were also assessed. The questionnaire visits took place at baseline and at 6 weeks, 3 months and 6 months post randomisation. The outcome assessors were blinded to the allocation groups. RESULTS: Of 628 participants screened for eligibility, nine were randomised to receive the study intervention (intervention group, n = 5; sham group, n = 4), six completed the CPP programme and eight completed the study. LIMITATIONS: Failure to achieve our expected recruitment targets led to early closure of the study by the funder. CONCLUSIONS: Because of the small number of participants recruited to the study, we were unable to draw any conclusions about the clinical effectiveness or cost-effectiveness of intra-articular lumbar facet-joint injections in the management of non-specific low back pain. Although we did not achieve the target recruitment rate from the pain clinics, we demonstrated our ability to develop a robust study protocol and deliver the intended interventions safely to all nine randomised participants, thus addressing many of the feasibility objectives. FUTURE WORK: Stronger collaborations with primary care may improve the recruitment of patients earlier in their pain trajectory who are suitable for inclusion in a future trial. TRIAL REGISTRATION: EudraCT 2014-003187-20 and Current Controlled Trials ISRCTN12191542. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 74. See the NIHR Journals Library website for further project information.

Recent advances in opioid prescription for chronic non-cancer pain.

Chronic pain is pain that persists past the normal time of healing, and is seen as a common problem with a significant socioeconomic impact. Pharmacological management for chronic non-cancer pain also involves the prescription of opioids, with the aim of an improved quality of life for the patient. New guidelines have been published to aid prescribing clinicians improve opioid safety and patient care, and include recommendations on when to refer patients to a pain specialist. In recent years there has been a rapid increase in opioid prescription in the UK and USA, prompting further concern regarding opioid abuse and side effects. Opioid use may also result in physical dependence and tolerance. Earlier recognition and diagnosis of unwanted effects of long-term opioid use is needed, such as opioid induced suppression of the hypothalamic-pituitary-gonadal axis, and opioid induced immunosuppression. Patients may themselves discontinue opioids, however, due to minor side effects. Recent advances in opioid prescription include the increasing use of transdermal preparations and extended release, oral, once daily preparations. New formulations of existing drugs have been developed, as well as a new chemical entity. Abuse deterrent formulations and delivery systems may prevent the artificial acceleration of drug delivery and reduce the potential for opioid addiction. Overdose concerns and the potential for fatal overdose may necessitate mandatory training for all clinicians who prescribe opioids. Despite the widespread use of opioids in the management of chronic non-cancer pain, significant research gaps remain. An improvement in the evidence base for its prescription is required.

Pulsed radio frequency: a non-neurodestructive therapy in pain management.

PURPOSE OF REVIEW: To appraise and discuss the current available evidence on pulsed radio frequency (PRF), with an emphasis on published randomized controlled clinical trials. RECENT FINDINGS: Pulsed radio frequency is a minimally invasive procedure used to treat a wide variety of chronic pain conditions. It is considered to be a safe and effective pain intervention with minimal side effects when performed by an experienced clinician with careful patient selection. Its mechanism of action is thought to be via neuromodulation, as 'pulses' of electric current are created at the electrode tip without a significant rise in temperature. Painful conditions successfully treated with PRF include chronic cervical radicular pain, trigeminal neuralgia, chronic shoulder pain and chronic low back pain. SUMMARY: At present very few well designed randomized controlled trials have been carried out on patients comparing PRF to another technique. Further scientific research and clinical trials are required to confirm whether PRF has a significant role in the future of chronic pain management.

Assessment and treatment of pain in children.

Treating acute pain in the paediatric population poses challenges which include the lack of high levels of evidence and a universal pain measuring tool, contributing to the undertreatment of pain. A multimodal approach of topical and systemic analgesia, comfort measures and parental involvement remains the mainstay of pain management.

Pain and uterine contractions during breast feeding in the immediate post-partum period increase with parity.

Previous research has shown that post-partum abdominal pain is greater in multiparous than primiparous women (Murray and Holdcroft, 1989). Although breast feeding in the immediate post-partum period induces uterine contractions and abdominal pain, it is unknown how parity influences the contractions. Here, a structured questionnaire that included the McGill Pain Questionnaire (total pain intensity index, TPI) and visual analog scales (VAS) was used to evaluate the intensity, location, referred tenderness (hyperalgesia), descriptor, and temporal characteristics of pain during breast feeding up to three days after uncomplicated vaginal delivery. Three groups of women were studied: primiparous (n=25); low parity (1-2 prior births; n=14); high parity (3-5 prior births; n=11). Uterine contractions during breast feeding were recorded using tocodynamometry in some women from each group (n=17, 6, 7, respectively). For comparison, an identical questionnaire was used to evaluate pains the women remembered experiencing during menstruation in the year immediately preceding the current pregnancy. During breast feeding, nearly all women (96%) reported deep pain primarily at three sites: lower abdomen, low back, and breast, with associated referred hyperalgesia in 62% of them. The intensity of these pains increased significantly with parity (P<0.001), along with an increase in the number of pain sites (P=0.03), mainly in lower abdomen and back, but not breast. Similarly, both the mean duration and number of uterine contractions increased significantly with parity (P<0.001). Furthermore, the mean duration of contractions correlated significantly with the pain scores (P=0.03 [VAS] and P=0.006 [TPI]). In contrast with pain during breast feeding, the intensity of pain during menstruation did not change with parity. These results demonstrate that pain, referred pain, and uterine contractions during breast feeding in the immediate post-partum period increase with parity, suggesting that childbirth can induce central neural changes that increase predisposition for pain during the post-partum period.