Balaji Yegneswaran

Systematic Review of the Quality and Generalizability of Studies on the Effects of Opioids on Driving and Cognitive/Psychomotor Performance

Introduction:The effect of opioids on driving performance has been much debated. Driving is a complex task requiring integration of psychomotor, cognitive, motor and decision-making skills, visual-spatial abilities, divided attention, and behavioral and emotional control. The objective of this systematic review was to assess the quality of studies and to revisit the concept that patients on stable opioids are safe to drive as it applies to everyday practice. Methods:We searched MEDLINE, EMBASE, PSYCinfo, CENTRAL, TRANSPORT, CINAHL, reference lists of retrieved articles and narrative reviews, for studies on chronic cancer and noncancer pain patients on opioids, tested by driving, driving simulator, or cognitive/psychomotor tests. Methodological quality was assessed with Methodological Index for Nonrandomized Studies, cognitive/psychomotor tests were appraised regarding their sensitivity and validation, and whether confounding variables potentially affecting the study conclusions were recorded. The results were analyzed both quantitatively and qualitatively. Results:We included 35 studies (2044 patients, 1994 controls), 9% of the studies were of poor, 54% of fair, and 37% of high quality; 3 quarters of the studies used high sensitivity cognitive tests. Amount and dose of opioids varied largely in many studies. Mean number of possible but unreported confounders was 2.2 (range, 0 to 4), relating to failure of the studies to mention coprescriptions with psychotropic effects, pain severity, sleep disorder or daytime somnolence, and/or significant depressive or anxiety-related problems. Interpretation:The commonly held concept that “chronic pain patients on stable opioids are safe to drive” cannot be generalized to all such patients in everyday practice, but may be applicable only to a subset who meet certain criteria.

Pain characteristics and demographics of patients attending a university-affiliated pain clinic in Toronto, Ontario

BACKGROUND Pain clinics tend to see more complex chronic pain patients than primary care settings, but the types of patients seen may differ among practices. OBJECTIVE The aim of the present observational study was to describe the pain and demographic characteristics of patients attending a university-affiliated tertiary care pain clinic in Toronto, Ontario. METHODS Data were collected on 1242 consecutive new patients seen over a three-year period at the Comprehensive Pain Program in central Toronto. RESULTS Musculoskeletal problems affecting large joints and the spine were the predominant cause of pain (more prevalent in women), followed by neuropathic disorders (more prevalent in men) in patients with recognizable physical pathology. The most affected age group was in the 35- to 49-year age range, with a mean pain duration of 7.8 years before the consultation. While 77% of the Comprehensive Pain Program patients had relevant and detectable physical pathology for pain complaints, three-quarters of the overall study population also had significant associated psychological or psychiatric comorbidity. Women, in general, attended the pain clinic in greater numbers and had less apparent physical pathology than men. Finally, less than one in five patients was employed at the time of referral. CONCLUSIONS The relevance of the data in relation to other pain clinics is discussed, as well as waiting lists and other barriers faced by chronic pain patients, pain practitioners and pain facilities in Ontario and Canada.

Pain characteristics of adults 65 years of age and older referred to a tertiary care pain clinic

BACKGROUND Reports indicate that characteristics of older adults with chronic pain may be different than those of younger persons. OBJECTIVE To study the pain characteristics of older patients presenting to a tertiary pain clinic for the first time. METHODS Age, sex and relative contributions of biomedical versus psychosocial variables contributing to chronic pain were investigated in patients 65 years of age and older, in comparison with younger patients, from a sample of 1242 consecutive new patients attending a tertiary care pain clinic. The presence of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision somatoform pain disorders were defined, using an explicated method of ascertaining the biomedical and psychological variables underlying the pain complaints. RESULTS The older patients (14.7% of the total sample) had relatively more physical problems (concordant with their complaints) but fewer psychological factors contributing to disability than the younger pain patients. Musculoskeletal and neuropathic disorders affected 40.7% and 35.2% of the older patients, respectively, while several patients had more than one painful disorder. Musculoskeletal problems were more prevalent in the women, and neuropathic problems were more prevalent in the men. CONCLUSIONS The older pain patients are a distinct group. Factors affecting the delayed presentation of older pain patients to the pain clinic and limitations of the present study are discussed.

Effects of Intravenous Sodium Amobarbital Vs Lidocaine on Pain and Sensory Abnormalities in Patients With Spinal Cord Injury

Abstract Objective: To compare the responses of patients with spinal cord injury (SCI) in regards to pain and sensory abnormalities to single blinded intravenous (IV) infusions of normal saline, sodium amobarbital, and lidocaine. Setting: Inpatient pain unit. Study Design: Retrospective chart review. Methods: Demographic data, body maps marking pain areas, pain ratings, standardized history and detailed examination were collected on admission in 5 patients with SCI and pain. IV normal saline was followed by either IV sodium amobarbital or lidocaine, respectively, (patients, but not the administering physician, were blinded to the order of the drugs). Spontaneous pain ratings and sensory abnormalities to light touch, pinprick and cold were documented at baseline and immediately after each infusion. Results: Sodium amobarbital decreased spontaneous pain by 73% (vs 46% with lidocaine) and normalized sensory abnormalities at or above the level of injury in 3 patients (as compared to just 1 patient with lidocaine), 2 of whom had transitional zone allodynia/hyperalgesia. Conclusion: In this small study, the analgesic effect of sodium amobarbital and its ability to modify sensory abnormalities appeared superior to that of lidocaine.