Evaluation of PAH diagnostic ratios as source apportionment tools for air particulates collected in an urban-industrial environment.

A variety of polycyclic aromatic hydrocarbon (PAH) diagnostic ratios were examined as source apportionment tools in the analysis of a PAH data set associated with atmospheric particulate matter collected in an urban-industrial environment. Seventy-six PM(10) samples were collected concurrently at 4 sampling sites over a one-month period in Hamilton, Ontario, Canada, a city of 500 000 people that is home to two integrated steel companies, associated industries and a network of roadways and major highways. Samples collected under well defined meteorological conditions were categorized as being 'upwind' or 'downwind' of the industrial sector. All sample extracts were analyzed for 48 parent PAH, methylphenanthrenes and sulfur-containing aromatics and showed a thousand-fold range of total PAH concentrations (0.23-172 ng m(-3)). Of all PAH diagnostic ratios examined, the two most useful were the anthracene/(anthracene+phenanthrene) and benz[a]anthracene/(benz[a]anthracene+chrysene/triphenylene) ratios. These afforded the best discrimination of samples that had significant industrial impacts. This work is the first example of the use of a linear combination of PAH ratios, coupled with total PAH data and well defined local samples to determine the relative impacts of mobile and industrial emissions in an urban-industrial environment. Use of a linear combination of PAH ratios allowed us to categorize 95% of the data as 'upwind' or 'downwind' of the industrial sector. It is important to determine PAH ratio threshold values based on data from well defined local samples rather than relying on literature values alone.

A comparative study of two factor analytic models applied to PAH data from inhalable air particulate collected in an urban-industrial environment.

Two factor analysis (FA)-based receptor modeling methods were applied to a polycyclic aromatic hydrocarbon (PAH) dataset from extracts of 75 PM(10) air particulate samples collected concurrently at 4 sampling sites proximate to the urban-industrial area in Hamilton, Ontario, Canada. The total PAH concentrations of 48 target compounds ranged from 0.23 to 172 ng m(-3). Principal component analysis (PCA) and positive matrix factorization (PMF) analysis were followed by multilinear regression analyses to identify and quantify PAH source contributions, together with spatial and temporal trends. The correlations between predicted and observed total PAH levels were excellent in both models (R(2) > 0.98). The PCA afforded large negative contributions in a number of samples, so further analysis was abandoned. The PMF analysis showed 3 factors which were identified as gasoline emissions, diesel emissions and coke oven emissions. Contributions of gasoline emissions and diesel emissions factors were surprisingly similar at all 4 sites indicative of a background of vehicle emissions across the city. The PMF coke oven emission factor showed the greatest variability in total loadings, consistent with the large PAH emissions from the steel industries and the large influence of wind direction on PAH concentrations. The highest coke oven contributions were observed at sites closest to the industrial area on days when these sites were downwind of the industries. The PMF coke oven impact factor showed good correlations with two commonly used PAH diagnostic ratios when the ratios were combined into a single ratio. This integrated approach allowed us to categorize >90% of the samples based on the wind direction of the impacting source.

Transdermal fentanyl versus sustained release oral morphine in strong-opioid naïve patients with chronic low back pain.

STUDY DESIGN: Open, randomized, parallel group multicenter study. OBJECTIVES: To compare the efficacy and safety of transdermal fentanyl (TDF) and sustained release morphine (SRM) in strong-opioid naïve patients with chronic low back pain (CLBP). SUMMARY OF BACKGROUND DATA: Most studies of TDF and SRM have involved patients already receiving strong opioids. This is the first large-scale study focusing on strong-opioid naïve patients with CLBP. METHODS: Adults with CLBP requiring regular strong opioid therapy received either TDF or SRM for 13 months. Starting doses were 25 microg/hr fentanyl patches every 72 hours or 30 mg oral morphine every 12 hours. Doses were adjusted according to response. Participants assessed pain relief and bowel function using weekly diaries. Other assessments, including quality of life, disease progression, and side effects, were made by patients and investigators. RESULTS: Data from 680 patients showed that TDF and SRM provided similar levels of pain relief, but TDF was associated with significantly less constipation than SRM, indicating a greater likelihood of satisfactory pain relief without unmanageable constipation for patients receiving TDF. Other ratings were similar for TDF and SRM, but TDF provided greater relief of pain at rest and at night. CONCLUSIONS: TDF and SRM provided equivalent levels of pain relief, but TDF was associated with less constipation. This study indicates that sustained-release strong opioids can safely be used in strong-opioid naïve patients.

Do strong opioids have a role in the early management of back pain? Recommendations from a European expert panel.

BACKGROUND: Since chronic low back pain (CLBP) is a complex biopsychosocial problem the ideal treatment is multimodal and multidisciplinary. However, in many countries, primary-care physicians care for many people with CLBP and have a pivotal role in selecting patients for more intensive treatments when these are available. Guidelines on the general use of strong opioids in chronic non-cancer pain have been published but, until now, no specific guidelines were available on their use in chronic low back pain. Given the prevalence of CLBP, and the complex nature of this multifactorial condition, it was felt that specific, evidence-based recommendations, with a focus on primary-care treatment, would be helpful. METHODS: An expert panel drawn from across Europe including pain specialists, anaesthetists, neurologists, rheumatologists, a general practitioner, an epidemiologist and the chairman of a pain charity was therefore convened. The aim of the group was to develop evidence-based recommendations that could be used as a framework for more specific guidelines to reflect local differences in the availability of specialist pain services and in the legal status and availability of strong opioids. Statements were based on published evidence (identified by a literature search) wherever possible, and supported by clinical experience when suitable evidence was lacking. RECOMMENDATIONS: Strong opioids have a role in the treatment of low back pain when other treatments have failed. They should be prescribed as part of a multimodal, and ideally interdisciplinary, treatment plan. The aim of treatment should be to relieve pain and facilitate rehabilitation.

A randomized, double-blind, placebo-controlled, cross-over pilot study to assess the effects of long-term opioid drug consumption and subsequent abstinence in chronic noncancer pain patients receiving controlled-release morphine.

OBJECTIVES: The long-term use of strong opioid analgesics among chronic noncancer pain (CNCP) patients remains controversial because of concerns over problematic drug use. However, previous surveys suggest that this is not necessarily the case. Therefore, we designed a controlled study to generate evidence in support of these findings. PATIENTS/SETTING: Ten CNCP patients attending the pain clinic in a district general hospital had been taking an average daily dose of 40 mg controlled-release morphine sulphate (mean 40, range 10-90, SD 21 mg), for an average of 2 years (mean 2.175, range 2-2.25, SD 0.2 years). DESIGN: Randomized, double-blind, placebo controlled cross-over study. The study was based on the premise that abrupt cessation of opioid drugs is most likely to highlight problematic use and the consequent inability to stop using opioids. Morphine was substituted with placebo for 60-hour periods to compare the effects of abstinence with those of continued use. Assessment of morphine cessation and abstinence effects was through direct observation, physiological measurements, questionnaire responses, and Brief Pain Inventory scores. RESULTS: Following cessation and abstinence, there were no indications of psychological dependence or drug craving, but there was evidence of the detrimental effects of pain intensity on activity, mood, relationships, sleep, and enjoyment of life. Three patients (30%) reported opioid drug withdrawal symptoms. Pharmacokinetic data demonstrated compliance with abstinence by all patients. CONCLUSION: The results suggest the existence of a group of CNCP patients whose long-term opioid consumption can be beneficial and remain moderate without them suffering from the consequences of problematic opioid drug use.

Recommendations for using opioids in chronic non-cancer pain.

1. The management of chronic pain should be directed by the underlying cause of the pain. Whatever the cause, the primary goal of patient care should be symptom control. 2. Opioid treatment should be considered for both continuous neuropathic and nociceptive pain if other reasonable therapies fail to provide adequate analgesia within a reasonable timeframe. 3. The aim of opioid treatment is to relieve pain and improve the patient's quality of life. Both of these should be assessed during a trial period. 4. The prescribing physician should be familiar with the patient's psychosocial status. 5. The use of sustained-release opioids administered at regular intervals is recommended. 6. Treatment should be monitored. 7. A contract setting out the patient's rights and responsibilities may help to emphasize the importance of patient involvement. 8. Opioid treatment should not be considered a lifelong treatment.

A survey of chronic noncancer pain patients prescribed opioid analgesics.

OBJECTIVES: Opioid analgesic drugs are sometimes advocated for chronic noncancer pain (CNCP). However, due to the paucity of studies assessing problematic opioid drug use in this population, evidence for such is inconclusive, and this issue remains controversial. This survey assessed problematic drug use among CNCP patients. PATIENTS/SETTING: Patients (N=104) prescribed opioids (mean duration of treatment 14.1 months) for severe CNCP at a pain clinic within a National Health Service hospital in London, United Kingdom. DESIGN: A review of pain clinic records to identify CNCP patients who had been prescribed opioids and subsequent assessment of those patients for problematic drug use using a substance use questionnaire. RESULTS: A total of 90 (86.5%) patients reported stopping opioid therapy at some point and, of these, 59 (65%) had ceased opioid therapy permanently. Of those patients who stopped opioids, 13 reported opioid withdrawal symptoms, two with severe and two with very severe symptoms. However, 72.5% of all patients derived benefit from opioids, although 77% of all patients reported opioid side effects. The addiction rate was 2.8%. CONCLUSION: These findings indicate that opioid therapy for CNCP does not necessarily lead to problematic drug use. Some problematic side effects are likely to be surmountable through appropriate prescribing. Further research is required into the long-term use of opioids in CNCP.

A pilot study into the problematic use of opioid analgesics in chronic non-cancer pain patients.

Controversy surrounds the use of strong opioid analgesic drugs for chronic non-cancer pain. Specialists have concluded that fears of problematic drug use are often unfounded. In contrast, others claim the existence of significant problems.'Problematic drug use' includes the following definitions; addiction, abuse, physiological dependence and tolerance.We present a case study and the results of a pilot, longitudinal, cohort study, via a pilot questionnaire, of 22 chronic pain clinic patients following a trial of opioid drugs. The results suggest that chronic non-cancer pain patients can be maintained on opioids with few problems, and likewise can withdraw with minimal adverse effects, other than a return of pain.