Geoff A. Bellingham

Duloxetine: a review of its pharmacology and use in chronic pain management.

Duloxetine is a serotonin and norepinephrine reuptake inhibitor that possesses antidepressant and pain-relieving properties. Compared with other antidepressants, it has a high affinity for both norepinephrine and serotonin reuptake transporters, which are relatively balanced. Analgesic onset has been observed within the first week of administration in randomized controlled trials and is likely obtained by enhancing the tone of the descending pain inhibition pathways of the central nervous system. Randomized trials have documented significant analgesic effects for managing chronic pain associated with fibromyalgia and diabetic peripheral neuropathic pain. Studies have also suggested that pain associated with major depressive disorder can be reduced with this medication. Modest effects for headache, osteoarthritic pain, and pain secondary to Parkinson disease have also been documented, but data are obtained from single-blinded or open-label trials that require further corroboration with larger randomized studies. Duloxetine has not yet been directly compared with other antidepressants or anticonvulsants for the treatment of pain syndromes.

Ultrasound-guided suprascapular nerve block: a correlation with fluoroscopic and cadaveric findings

PurposePrevious work on the ultrasound-guided injection technique and the sonoanatomy of the suprascapular region relevant to the suprascapular nerve (SSN) block suggested that the ultrasound scan showed the presence of the suprascapular notch and transverse ligament. The intended target of the ultrasound-guided injection was the notch. The objective of this case report and the subsequent cadaver dissection findings is to reassess the interpretation of the ultrasound images when locating structures for SSN block.Clinical featuresA 45-yr-old man with chronic shoulder pain received an ultrasound-guided SSN block using the suprascapular notch as the intended target. The position of the needle was verified by fluoroscopy, which showed the tip of the needle well outside the suprascapular notch. Similar ultrasound-guided SSN blocks were performed in two cadavers. Dissections were performed which showed that the needle tips were not at the suprascapular notch but, more accurately, were close to the SSN but at the floor of the suprascapular fossa between the suprascapular and spinoglenoid notch.ConclusionOur fluoroscopic and cadaver dissection findings both suggest that the ultrasound image of the SSN block shown by the well-described technique is actually targeting the nerve on the floor of the suprascapular spine between the suprascapular and spinoglenoid notches rather than the suprascapular notch itself. The structure previously identified as the transverse ligament is actually the fascia layer of the supraspinatus muscle.RésuméObjectifDes travaux précédents portant sur une technique d’injection par échoguidage et la sono-anatomie de la région suprascapulaire pertinente pour les blocs du nerf suprascapulaire (NSS) suggéraient que l’échogramme montrait la présence de l’échancrure suprascapulaire et du ligament transverse. L’échancrure était la cible de l’injection par échoguidage. L’objectif de cette présentation de cas et des résultats subséquents de dissection cadavérique était de réévaluer l’interprétation des images échoguidées lors de la localisation des structures pour la réalisation d’un bloc du NSS.Éléments cliniquesUn homme de 45 ans souffrant de douleur chronique à l’épaule a reçu un bloc du NSS échoguidé en utilisant l’échancrure suprascapulaire comme cible. La position de l’aiguille a été vérifiée par fluoroscopie, ce qui a montré que la pointe de l’aiguille était à l’extérieur de l’échancrure suprascapulaire. Des blocs du NSS semblables ont été réalisés par échoguidage sur deux cadavres. La dissection des cadavres a démontré que les pointes des aiguilles n’étaient pas situées au niveau de l’échancrure suprascapulaire mais, plus précisément, étaient proches du NSS mais au niveau du plancher de la fosse suprascapulaire, entre les échancrures suprascapulaire et spino-glénoïdienne.ConclusionLes résultats de fluoroscopie et de dissection des cadavres suggèrent que l’échogramme du bloc du NSS montré par cette technique bien décrite cible en fait le nerf sur le plancher de l’épine suprascapulaire entre les échancrures suprascapulaire et spino-glénoïdienne plutôt que l’échancrure suprascapulaire en soi. La structure qui avait été précédemment identifiées comme le ligament transverse est en fait la couche de l’aponévrose du muscle supra-épineux.

Randomized controlled trial comparing pudendal nerve block under ultrasound and fluoroscopic guidance.

Background Although fluoroscopy is an established imaging modality for pudendal nerve block, ultrasound (US) technique allows physicians better visualization of anatomic structures. This study aimed to compare the effectiveness and safety between the US- and fluoroscopy-guided techniques. Methods A randomized, single-blind, split-plot design was used to conduct the study. Twenty-three patients undergoing bilateral pudendal nerve blocks received US-guided injections to either the left or right side, whereas the contralateral side received a fluoroscopic-guided injection in randomized sequence. Injections consisted of 4 mL of 0.5% bupivacaine and 40 mg methylprednisone. The primary outcome was the success of the block in the distribution of the pudendal nerve along the perineum, rated as either absent, moderate, or strong. Secondary outcomes were the time to administer the blocks, quality of visualization of anatomic structures using US and fluoroscopy, distance of the final US-guided needle position from the ischial spine, and incidence of adverse effects. Results No differences in the degree of neural blockade were noted between US- or fluoroscopic-guided techniques for either temperature or pinprick blockade. Time to complete the procedure was significantly longer using US compared with fluoroscopy (219 [SD, 65] and 428 [SD, 151] secs, P < 0.0001). No significant differences were noted regarding the occurrence of adverse effects between the 2 techniques. Conclusions Ultrasound-guided pudendal nerve blockade is as accurate as fluoroscopically guided injections when performed by an experienced clinician. However, the former took a longer time to perform.

Postoperative pain management in patients with chronic kidney disease

Chronic kidney disease (CKD) is a health care problem with increasing prevalence worldwide. Pain management represents one of the challenges in providing perioperative care for this group of patients. Physicians from different specialties may be involved in pain management of CKD patients, especially in advanced stages. It is important to understand the clinical staging of kidney function in CKD patients as the pharmacotherapeutic pain management strategies change as kidney function becomes progressively impaired. Special emphasis should be placed on dose adjustment of certain analgesics as well as prevention of further deterioration of renal function that could be induced by certain classes of analgesics. Chronic pain is a common finding in CKD patients which may be caused by the primary disease that led to kidney damage or can be a direct result of CKD and hemodialysis. The presence of chronic pain in some of the CKD patients makes postoperative pain management in these patients more challenging. This review focuses on the plans and challenges of postoperative pain management for patient at different stages of CKD undergoing surgical intervention to provide optimum pain control for this patient population. Further clinical studies are required to address the optimal medication regimen for postoperative pain management in the different stages of CKD.

Case report: Retroperitoneoscopic pheochromocytoma removal in an adult with Eisenmenger’s syndrome

Purpose: Patients with uncorrected or palliated, complex congenital heart lesions requiring surgery can benefit from laparoscopic techniques, but retroperitoneal insufflation may render them hemodynamically unstable. Alterations in cardiopulmonary physiology during retroperitoneal insufflation have been studied, yet there are no cases detailing this approach in patients with congenital heart lesions. We present a case of a pheochromocytoma removal via retroperitoneoscopy in a patient with a palliated, complex heart lesion.Clinical features: A 28-yr-old woman was admitted for removal of a pheochromocytoma through retroperitoneoscopy. The main feature of her heart disease was a complete atrioventricular canal defect. She eventually developed Eisenmenger’s syndrome and became chronically cyanotic. Retroperitoneal insufflation with CO2 gas did not change hemodynamic variables. Significant increases in peak airway pressures were encountered, possibly due to the distending effects of insufflation, or due to increasing the minute ventilation to reduce exogenous CO2. Arterial CO2 remained stable, but a significant increase between end-tidal and arterial levels became apparent with insufflation. Tumour manipulation led to systemic (and possibly pulmonary) hypertension, which exacerbated ventricular dysfunction. This condition resulted in atrioventricular valve regurgitation, as seen on transesophageal echocardiography, and diminished pulmonary blood flow with subsequent desaturation. These changes resolved with antihypertensive medications. The patient’s trachea was extubated four hours postoperatively, and she recovered uneventfully.Conclusion: Patients with altered cardiopulmonary physiology may tolerate retroperitoneoscopic insufflation with relative hemodynamic stability. Appropriate use of short-acting, vasoactive drugs and aggressive monitoring of PaCO2 and hemodynamic variables is required.RésuméObjectif: Les patients ayant des lésions cardiaques congénitales complexes non corrigées ou palliées nécessitant une chirurgie peuvent profiter de techniques laparoscopiques; toutefois, un rétropneumopéritoine peut rendre leur hémodynamie instable. Les modifications de la physiologie cardiopulmonaire pendant un rétropneumopéritoine ont été étudiées, mais il n’existe aucun cas décrivant cette approche chez des patients souffrant d’anomalies cardiaques congénitales. Nous présentons un cas d’ablation de phéochromocytome par rétropéritonéoscopie chez un patient ayant une anomalie cardiaque congénitale complexe palliée.Éléments cliniques: Une femme de 28 ans a été admise pour une ablation de phéochromocytome par rétropéritonéoscopie. Une déficience totale de son canal atrio-ventriculaire constituait l’élément principal de sa maladie cardiaque. Elle a finalement développé un syndrome d’Eisenmenger et est devenue chroniquement cyanotique. Un rétropneumopéritoine avec du gaz CO2 n’a pas modifié les variables hémodynamiques. Des augmentations significatives dans les pics de pression ventilatoire ont été observées, possiblement provoquées par les effets distensifs de l’insufflation ou par l’augmentation de la ventilation minute pour réduire le CO2 exogène. Le CO2 artériel est resté stable, mais une augmentation significative entre les niveaux télé-expiratoire et artériel est apparue lors de l’insufflation. La manipulation tumorale a provoqué une hypertension systémique (et possiblement pulmonaire), ce qui a exacerbé la dysfonction ventriculaire. La conséquence de cette condition a été une régurgitation des valves atrio-ventriculaires, telle qu’observées par échocardiographie transoesophagienne, et un débit sanguin pulmonaire réduit avec une désaturation subséquente. Ces modifications ont pu être contrées avec des médicaments anti-hypertenseurs. La trachée de la patiente a été extubée quatre heures après l’opération, et elle s’est rétablie normalement.Conclusion: Les patients présentant une physiologie cardiopulmonaire altérée pourraient tolérer un rétropneumopéritoine et maintenir une hémodynamie relativement stable. L’utilisation adéquate de médicaments vasoactifs à action courte et une surveillance agressive de la PaCO2 et des variables hémodynamiques sont nécessaires.

Perioperative Addiction: Clinical Management of the Addicted Patient

This publication by Springer provides readers with a valuable textbook concerning the clinical management of the addicted patient in the perioperative period. The focus of the information presented is on the physiological and pharmacological challenges of these patients and how these difficulties are best managed. The text is centred predominantly on acute perioperative care and does not explore other management issues commonly encountered in addiction medicine, such as cognitive behavioural or psychiatric therapies. The contributing authors are predominantly physicians practicing anesthesiology. The book is divided into three parts. Part I provides readers with a general background on the disease of addiction. The text ranges from historical accounts of the introduction of drugs to ancient civilizations to descriptions of contemporary functional magnetic resonance imaging and genetic studies of the addicted brain. The final chapter in Part 1 is on pharmacological approaches to the treatment of addiction with a focus on the use of methadone and buprenorphine. This chapter presents a clear and understandable discussion for those not accustomed to the use of these drugs. Issues surrounding the perioperative administration of these drugs are also addressed and suitably explored for perioperative care providers. Part II of the book offers readers an overview of specific drug classes of abuse, including chapters on opioids, club drugs, cocaine, and alcohol. The text is well written with a focus on the pertinent pharmacological and physiological issues of each drug in the perioperative environment. The discussions, which are divided into the preoperative, intraoperative, and postoperative phases of surgery, are written in a clear, concise, and comprehensive manner. The chapter on propofol addiction is especially significant and likely the most comprehensive summary of the subject matter to date. Although Part II is well written, it falls somewhat short in that some drug classes are conspicuously absent or the detail may be less comprehensive than desired. For example, no mention is made of the barbiturates or anabolic steroids. Both categories of drugs can produce profound pharmacological and physiological challenges in perioperative care that would have been valuable to discuss. The focus of Part III, the final section of the book, is on discussions of specific populations in the context of addiction. Some of these chapters include drug-seeking healthcare professionals, pregnant women, adolescent populations, or individuals recovering from substance abuse. Fundamental principles on managing these populations are summarized in this section, and it makes a suitable resource for the perioperative clinician. The chapters are varied in their content in terms of the amount and type of clinical information provided. For example, the chapter on the drug-seeking healthcare professional discusses many social issues (legal, financial, family, and intervention), while the chapter on the patient recovering from substance abuse has a more pharmacological focus with discussions regarding adjunctive anesthetic agents and drug-drug interactions. G. A. Bellingham, MD (&) Schulich School of Medicine & Dentistry, Western University, London, ON, Canada

Pudendal Nerve Blockade

The pudendal nerve is a branch of the sacral plexus, originating from the ventral rami of S2, 3, and 4 nerve roots. It provides sensory innervation to the skin of the perineum and mucosa of the anal canal. It also provides motor control of the external anal sphincter, urethral sphincter, and perineal musculature [1–6].