David Janfaza

Urine toxicology screening among chronic pain patients on opioid therapy: frequency and predictability of abnormal findings.

ObjectiveTo examine the incidence of abnormal urine toxicology screening among chronic pain patients prescribed opioids for their pain and to relate these results to patient descriptors and type, number, and dose of prescribed opioids. MethodsA retrospective analysis of data from 470 patients who had urine screening at a pain management program in an urban teaching hospital was performed. Urine samples were analyzed using gas chromatography-mass spectrometry. Patients were categorized as having urine screens that were “normal” (expected findings based on their prescribed drugs) or abnormal. Abnormal findings were those of (1) absence of a prescribed opioid, (2) presence of an additional nonprescribed controlled substance, (3) detection of an illicit substance, and (4) an adulterated urine sample. ResultsForty-five percent of the patients were found to have abnormal urine screens. Twenty percent were categorized as having an illicit substance in their urine. Illicit substances and additional drugs were found more frequently in younger patients than in older patients (P<0.001). No other variables were found to predict abnormal urine screen results. DiscussionThese results confirm past findings that random urine toxicology screens among patients prescribed opioids for pain reveal a high incidence of abnormal findings. Common patient descriptors, and number, type, and dose of prescribed opioids were found to be poor predictors of abnormal results.

Psychiatric Comorbidity Is Associated Prospectively with Diminished Opioid Analgesia and Increased Opioid Misuse in Patients with Chronic Low Back Pain.

Background:Opioids are frequently prescribed for chronic low back pain (CLBP), but there are little prospective data on which patient subgroups may benefit. Psychiatric comorbidity, such as high levels of depression and anxiety symptoms (termed comorbid negative affect [NA]), is a common presentation and may predict diminished opioid analgesia and/or increased opioid misuse. Methods:The authors conducted a 6½-month prospective cohort study of oral opioid therapy, with an active drug/placebo run-in period, in 81 CLBP patients with low, moderate, and high levels of NA. Treatment included an opioid titration phase with a prescribing physician blinded to NA group assignment and a 4-month continuation phase, during which subjects recorded daily pain levels using an electronic diary. The primary outcome was the percent improvement in average daily pain, summarized weekly. Results:There was an overall 25% dropout rate. Despite the high NA group being prescribed a higher average daily dose of morphine equivalents, linear mixed model analysis revealed that the 24 study completers in each of the high NA and low NA groups had an average 21 versus 39% improvement in pain, respectively (P < 0.01). The high NA group also had a significantly greater rate of opioid misuse (39 vs. 8%, P < 0.05) and significantly more and intense opioid side effects (P < 0.01). Conclusions:These results indicate that the benefit and risk considerations in CLBP patients with high NA versus low NA are distinctly different. Thus, NA is an important phenotypic variable to characterize at baseline, before deciding whether to prescribe opioids for CLBP.

Interpreting Urine Drug Tests: Prevalence of Morphine Metabolism to Hydromorphone in Chronic Pain Patients Treated with Morphine

OBJECTIVE Pain medicine practitioners frequently use urine drug testing (UDT) to monitor adherence to opioid therapy. It can be difficult to interpret a result as normal or abnormal in relation to which opioid compounds are expected to be found in the urine. We investigated whether hydromorphone may be a metabolite of morphine normally appearing in UDT of patients prescribed morphine. DESIGN This is a retrospective case-control study of urine toxicology results in pain patients taking only morphine. Inclusion criteria included urine results positive for morphine only (controls) or morphine and hydromorphone (cases). Demographic and medical history variables, and any history of aberrant drug behavior were recorded and related to the presence or absence of hydromorphone in the urine. RESULTS Hydromorphone was present in 21 of 32 cases (66%), none of whom had a history of aberrant drug behavior. Positive cases occurred more frequently in women, in those taking higher daily doses of morphine, and in those with higher urine morphine concentrations (P < 0.05). Only morphine urine concentration was a significant predictor of the hydromorphone metabolite in a logistic regression model (P < 0.05). CONCLUSIONS Hydromorphone is likely a minor metabolite of morphine, normally appearing in the UDT of patients taking morphine. This finding assists in determining whether a UDT result is normal or abnormal, and subsequently whether a patient is compliant with opioid therapy. This observation should be confirmed by a prospective study in a controlled environment. Variables such as gender, morphine dose, morphine urine concentration, and genetic determinants of morphine metabolism should be investigated further.

The ultrasound-guided retrolaminar block

PurposeParavertebral blocks have gained in popularity and offer the possible benefit of reduced adverse effects when compared with epidural analgesia. Nevertheless, pulmonary complications in the form of inadvertent pleural puncture are still a recognized risk. Also, the traditional paravertebral blocks are often technically difficult even with ultrasound guidance and constitute deep non-compressible area injections. We present our experience with the first three patients receiving ultrasound-guided retrolaminar blocks for managing the pain associated with multiple rib fractures.Clinical featuresThe vertebral laminae are identified by ultrasound imaging in a paramedian sagittal plane by sequentially visualizing the pleura and ribs, transverse processes, and the corresponding laminae (from lateral to medial). The block needle is guided to contact the lamina, and the local anesthetic injectate is visualized under real-time imaging. A catheter is inserted and used for continuous analgesia. In three consecutive patients, verbal rating scale (VRS) pain scores were reduced from 10/10 to less than 5/10, and no technical difficulties, complications, or adverse effects were encountered.ConclusionsSuccessful analgesia was achieved in all three cases utilizing continuous infusion and intermittent boluses with ultrasound-guided retrolaminar blocks. These results show the feasibility of this approach for patients with multiple rib fractures.RésuméObjectifLes blocs paravertébraux ont gagné en popularité et offrent l’avantage de réduire potentiellement les effets secondaires comparativement à l’analgésie péridurale. Toutefois, les complications pulmonaires, sous forme de ponction pleurale involontaire, demeurent un risque bien connu. En outre, les blocs paravertébraux conventionnels sont souvent difficiles à réaliser d’un point de vue technique et ce, même sous échoguidage, étant donné qu’il s’agit d’injections profondes réalisées dans des zones non compressibles. Nous rapportons notre expérience auprès des trois premiers patients à recevoir un bloc rétrolaminaire échoguidé pour la prise en charge de la douleur associée à une fracture multiple des côtes.Éléments cliniquesLes lames vertébrales sont identifiées par ultrason dans un plan sagittal paramédian en visualisant la plèvre et les côtes, les apophyses transverses, et les lames correspondantes (des lames latérales aux médiales) séquentiellement. L’aiguille du bloc est guidée jusqu’à ce qu’elle atteigne la lame, et l’anesthésique local injecté est visualisé par imagerie en temps réel. Un cathéter est inséré et utilisé pour l’analgésie en continu. Chez trois patients consécutifs, les scores de douleur sur une échelle visuelle ont baissé de 10/10 à moins de 5/10, et aucune difficulté technique, complication ou effet secondaire n’a été rapporté.ConclusionDans les trois cas, l’analgésie a été réalisée grâce à une perfusion continue et des bolus intermittents avec des blocs rétrolaminaires échoguidés. Ces résultats montrent la faisabilité de cette approche pour les patients présentant des fractures multiples des côtes.

Bedside implantation of a trial spinal cord stimulator for intractable anginal pain.

I ntractable angina secondary to severe coronary artery disease is responsive to spinal cord stimulation when other conventional therapies have failed (1,2). Spinal cord stimulation improves pain control and has antiischemic effects in patients with intractable angina (3). In this case report, we describe a novel approach to the placement of a temporary spinal cord stimulator at the bedside in a patient with intractable angina. This approach eliminated the need to move a critically ill patient from the coronary care unit to radiology for this procedure. Spinal cord stimulation successfully relieved the angina1 pain and improved the electrocardiographic signs of ischemia.

Ultrasound-guided retrolaminar paravertebral block

would necessarily avoid the drug error described in Muddanna et al.’s letter, and colour-coding of drugs would not have prevented any of our incidents. On our delivery suite, Syntocinon (or carbetocin depending on our guidelines) is never drawn up in advance of caesarean section and when drawn up ahead of administration, we encourage that it is kept separate from all other drugs on a different part of the anaesthetic machine. Even better would be to draw it up at the time it is needed whilst following our ten commandments. There will never be a failsafe method and colour-coding does not solve all problems, but formal teaching of our juniors is a sensible step and stressing our tenth commandment, we hope, will result in extra vigilance by the anaesthetist administering the drug.

The clinical impact of a false-positive urine cocaine screening result on a patient's pain management.

BACKGROUND The urine of a patient admitted for chest and epigastric pain tested positive for cocaine using an immunoassay-based drug screening method (positive/negative cutoff concentration 150 ng/mL). Despite the patients denial of recent cocaine use, this positive cocaine screening result in conjunction with a remote history of drug misuse impacted the patients recommended pain therapy. Specifically, these factors prompted the clinical team to question the appropriateness of opioids and other potentially addictive therapeutics during the treatment of cancer pain from previously undetected advanced pancreatic carcinoma. OBJECTIVE After pain management and clinical pathology consultation, it was decided that the positive cocaine screening result should be confirmed by gas chromatography-mass spectrometry (GC-MS) testing. RESULTS This more sensitive and specific analytical technique revealed that both cocaine and its primary metabolite benzoylecgonine were undetectable (i.e., less than the assay detection limit of 50 ng/mL), thus indicating that the positive urine screening result was falsely positive. With this confirmation, the pain management service team was reassured in offering intrathecal pump (ITP) therapy for pain control. ITP implantation was well tolerated, and the patient eventually achieved excellent pain relief. However, ITP therapy most likely would not have been utilized without the GC-MS confirmation testing unless alternative options failed and extensive vigilant monitoring was initiated. CONCLUSION As exemplified in this case, confirmatory drug testing should be performed on specimens with unexpected immunoassay-based drug screening results. To our knowledge, this is the first report of a false-positive urine cocaine screening result and its impact on patient management.

Prediction of Pain and Opioid Utilization in the Perioperative Period in Patients Undergoing Primary Knee Arthroplasty: Psychophysical and Psychosocial Factors

Objective To identify factors associated with pain severity and opioid consumption in the early perioperative period. Design Prospective observational cohort study. Setting Tertiary academic medical center. Subjects Patients with osteoarthritis older than age 45 years undergoing primary total knee replacement at Brigham and Womens Hospital. A total of 126 patients enrolled. Methods Preoperatively, pain questionnaires and quantitative sensory testing were performed on patients to develop a psychosocial and psychophysical profile. Postoperatively, pain scores and opioid consumption were measured as primary end points. Univariate and multiple linear regression analyses were performed to determine the predictive value of these characteristics on perioperative pain scores and opioid consumption. Results Regression analysis revealed several predictors of acute postoperative pain scores including temporal summation of pain (TSP; P = 0.001), body mass index (BMI; P = 0.044), number of previous knee surgeries (P = 0.006), and female gender (P = 0.023). Similarly, predictors of opioid utilization included TSP (P = 0.011), BMI (P = 0.02), age (P = <0.001), and tourniquet time (P = 0.003). Conclusions The only significant, unique predictors of both pain and opioid consumption were TSP, an index of central pain facilitatory processes, and BMI. Interestingly, psychosocial factors, such as catastrophizing and somatization, although correlated with postoperative pain scores and opioid consumption, generally did not independently explain substantial variance in these measures. This study suggests that BMI and quantitative sensory testing, specifically the temporal summation of pain, may provide value in the preoperative assessment of patients undergoing total knee arthroplasty and other surgeries via predicting their level of risk for adverse pain outcomes.

Total Hip Replacement

Perioperative management of the patient for total joint surgery involves a basic understanding of the patient’s preexisting conditions, the surgical plan, and the potential for intraoperative complications. This patient population often presents with multiple comorbidities, in addition to degenerative joint disease, which can complicate the perioperative course. Proper preoperative workup and intraoperative monitoring are paramount in reducing morbidity and mortality. Choice of anesthetic technique (Regional vs. General) should not only take into consideration preexisting conditions, but also length or surgery, risk of nerve injury, and potential for blood loss. The most common complication to occur during joint replacement surgery is acute blood loss, followed by venothromboembolism. Although the incidence of these events is relatively low, given the new advances in anesthetic and surgical techniques, it is important to recognize in the setting of intraoperative hypotension. Postoperative management of the orthopedic patient includes adequate analgesia with multimodal techniques utilizing both pharmacologic methods and regional anesthetic techniques with the aim of facilitating early ambulation.