Rakesh V. Sondekoppam

A Comparison of Combined Suprascapular and Axillary Nerve Blocks to Interscalene Nerve Block for Analgesia in Arthroscopic Shoulder Surgery: An Equivalence Study.

Background and Objectives The primary objective of this study was to compare the analgesic efficacy of combined suprascapular and axillary nerve block (SSAX) with interscalene block (ISB) after arthroscopic shoulder surgery. Our hypothesis was that ultrasound-guided SSAX would provide postoperative analgesia equivalent to ISB. Methods Sixty adult patients undergoing arthroscopic shoulder surgery received either SSAX or ISB prior to general anesthesia, in a randomized fashion. Pain scores, satisfaction, and adverse effects were recorded in the recovery room, 6 hours, 24 hours, and 7 days after surgery. Results Combined suprascapular and axillary nerve block provided nonequivalent analgesia when compared with ISB at different time points postoperatively, except on postoperative day 7. Interscalene block had better mean static pain score in the recovery room (ISB 1.80 [95% confidence interval [CI], 1.10–2.50] vs SSAX 5.45 [95% CI, 4.40–6.49; P < 0.001]). At 24 hours, SSAX had better mean static pain score (ISB 6.35 [95% CI, 5.16–7.54] vs SSAX 3.92 [95% CI, 2.52–5.31]; P = 0.01) with similar satisfaction between the groups. Conclusions Combined suprascapular and axillary nerve block provides nonequivalent analgesia compared with ISB after arthroscopic shoulder surgery. While SSAX provides better quality pain relief at rest and fewer adverse effects at 24 hours, ISB provides better analgesia in the immediate postoperative period. For arthroscopic shoulder surgery, SSAX can be a clinically acceptable analgesic option with different analgesic profile compared with ISB.

Comparison of efficacy and safety of lateral-to-medial continuous transversus abdominis plane block with thoracic epidural analgesia in patients undergoing abdominal surgery: A randomised, open-label feasibility study.

BACKGROUND We recently described a lateral-to-medial approach for transversus abdominis plane (LM-TAP) block, which may permit preoperative initiation of the block. OBJECTIVE Our objective was to evaluate the feasibility of continuous LM-TAP blocks in clinical practice in comparison with thoracic epidural analgesia (TEA). DESIGN A randomised, open-label study. SETTING University Hospital, London Health Sciences Centre, London, Ontario, Canada from July 2008 to August 2012. PATIENTS Fifty adult patients undergoing open abdominal surgery via laparotomy were allocated randomly to receive preoperative catheter-congruent TEA or ultrasound-guided continuous bilateral LM-TAP block for 72 h postoperatively. Reasons for noninclusion were American Society of Anesthesiologists’ physical status more than 4, known allergy to study drugs, chronic pain/opioid dependence, spinal abnormalities or psychiatric illness. INTERVENTIONS In the TEA group (n = 24), patient-controlled epidural analgesia was maintained using bupivacaine 0.1% with hydromorphone 10 &mgr;g ml−1 after establishment of the initial block. In the LM-TAP group (n = 26), ultrasound-guided LM-TAP catheters were inserted on each side preoperatively after a bolus of 30 ml of ropivacaine 0.5% (20 ml subcostal and 10 ml subumbilical injections on both sides). Analgesia was maintained with an infusion of ropivacaine 0.35% at a rate of 2 to 2.5 ml h−1 through each catheter, along with rescue intravenous patient-controlled analgesia. MAIN OUTCOME MEASURES The primary outcome was pain score on coughing 24 h after the end of surgery. Secondary outcomes were pain scores from 24 to 72 h, intraoperative and postoperative opioid consumption, time to onset of bowel movement and side effect profiles. RESULTS Mean [95% confidence interval (95% CI)] pain scores at rest ranged from 1. 7 (0.9 to 2.5) to 2.3 (1.1 to 3.4) in TEA vs. 1.5 (0.7 to 2.2) to 2.2 (1.3 to 3.0) in LM-TAP (P = 0.829). The dynamic pain scores ranged from 2.9 (1.5 to 4.4) to 3.8 (2.8 to 4.8) in TEA vs. 3.3 (2.4 to 4.3) to 3.8 (2.7 to 4.9) in LM-TAP (P = 0.551). The variability in pain scores was lower in the LM-TAP group than in the TEA group in the first 24 h postoperatively. Patient satisfaction and other secondary outcomes were similar. CONCLUSION Continuous bilateral LM-TAP block can be initiated preoperatively and may provide comparable analgesia to TEA in patients undergoing laparotomy. CLINICAL TRIALS REGISTRY not registered because registration was not mandatory at the time of starting the trial.

Injectate spread following ultrasound-guided lateral to medial approach for dual transversus abdominis plane blocks.

Bilateral dual transversus abdominis plane (BD‐TAP) injections were devised to cover the T7–8 and L1 dermatomes, which are usually spared with classical and mid‐axillary TAP injections. The purpose of this study was to delineate the vertical and lateral extent of injectate spread following a lateral to medial approach for TAP injections in embalmed cadavers.

Factors Associated With Risk of Neurologic Complications After Peripheral Nerve Blocks: A Systematic Review.

The onset of neurologic complications after regional anesthesia is a complex process and may result from an interaction of host, agent, and environmental risk factors. The purpose of this systematic review was examine the qualitative evidence relating to various risk factors implicated in neurologic dysfunction after peripheral nerve block (PNB). The MEDLINE, OVID, and EMBASE databases were primary sources for literature. Cochrane, LILACS, DARE, IndMed, ERIC, NHS, and HTA via Centre for Reviews and Dissemination (CRD; York University) databases were searched for additional unique results. Randomized controlled studies, case–control studies, cohort studies, retrospective reviews, and case reports/case series reporting neurologic outcomes after PNB were included. Relevant, good-quality systematic reviews were also eligible. Human and animal studies evaluating factors important for neurologic outcomes were assessed separately. Information on study design, outcomes, and quality was extracted and reviewed independently by the 2 review authors. An overall rating of the quality of evidence was assigned using GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. Relevant full-text articles were separated based on type (prospective, retrospective, and nonhuman studies). Strengths of association were defined as high, moderate, inconclusive, or inadequate based on study quality and direction of association. The evidence from 77 human studies was reviewed to assess various host, agent, and environmental factors that have been implicated as possible risks. Most of the available evidence regarding the injurious effects of the 3 cardinal agents of mechanical insult, pressure, and neurotoxicity was extracted from animal studies (42 studies). Among the risk factors investigated in humans, block type had a strong association with neurologic outcome. Intraneural injection, which seems to occur commonly with PNBs, showed an inconsistent direction of association. Measures meant to increase precision and ostensibly reduce the occurrence of complications such as currently available guidance techniques showed little effect on the incidence of neurologic complications. Recovery from neurologic injury appears to be worse in patients with pre-existing risk factors. Categorization and definition of neurologic complication varied among studies, making synthesis of evidence difficult. Also, a significant portion of the evidence surrounding neurologic injury associated with PNB comes from animal or laboratory studies, the results of which are difficult to translate to clinical scenarios. Of the human studies, few had an a priori design to test associations between a specific risk factor exposure and resultant neurologic sequelae. A few risk factor associations were identified in human studies, but overall quality of evidence was low. Much of the evidence for risk factors comes from animal models and case reports. The final neurologic outcome seems to represent the complex interaction of the host, agent, and the environment.

An ultrasound-guided ABCDE approach with a sniff test to evaluate diaphragmatic function without acoustic windows

To the Editor, Interscalene block is known to result in phrenic nerve paralysis (PNP) and diaphragmatic dysfunction. The reported incidence of PNP is variable depending on the site of performance and the volume of local anesthetic used. Blocking the normal hemidiaphragm can lead to significant respiratory morbidity in certain patients, particularly those with preexisting respiratory disease. A simple, easily repeatable bedside test is therefore desirable for assessing diaphragmatic function perioperatively, especially in the context of interscalene block. Various ultrasound-based techniques described previously to visualize the diaphragm suffer from poor reproducibility, depend on operator experience, or involve measuring the amplitude of motion or change in diaphragm thickness, with subsequent calculations. The ease of imaging on the left side is challenging because of the limited acoustic window due to the presence of the spleen, making ultrasound techniques less reproducible over the course of the block. In an attempt to overcome these drawbacks, we developed an ultrasound-guided sniff test to evaluate qualitatively the change in diaphragmatic thickness and the direction of motion in the context of interscalene block. As illustrated in the Figure, this novel technique utilizes the previously described systematic ABCD approach for evaluating the diaphragm (at the anterior Axillary line, watch Breathing, move the probe Caudad, and perform Diaphragmatic Evaluation). After locating the muscular part of the diaphragm, the sniff test is applied, and the change in thickness of the diaphragm noted via both B-mode and M-mode ultrasonography. During the sniff test, we often note that there is a directional motion of the diaphragm on M-mode ultrasonography. When the diaphragm is functioning normally, there is a brief descent of the diaphragm during the sniff, as reflected by a downward spike in M mode (with the probe directed cephalad). An upward spike in M mode indicates a paradoxical motion that is seen in a paralysed diaphragm (Figure). It is well known that the change in thickness of the muscular part of the diaphragm is an indicator of diaphragmatic function. By applying a rapid sniff such as that used in our technique, this change is accentuated and can serve as an objective sign of diaphragmatic contraction and a functioning phrenic nerve. The physiological phenomenon underlying paradoxical upward motion can best be explained by the effect of trans-diaphragmatic pressure changes on the paralyzed diaphragm. Normally during inspiration, the diaphragm muscle thickens and moves downward, creating positive intra-abdominal pressure and negative intrathoracic pressure. This sequence can be appreciated as active thickening and a downward deflection upon inspiration (away from the probe). When one hemidiaphragm is paralyzed (such as during phrenic nerve blockade from an interscalene block), the opposite side tries to compensate to maintain nearnormal trans-diaphragmatic pressure via increased neural drive. It results in upward displacement of the paralyzed side of the diaphragm. These changes are accentuated upon sniffing and are appreciated easily when incorporated as a part of the assessment technique. Previous investigators have noted the utility of an ultrasound-guided sniff test by looking at the central L. Y. S. Naik, MBBS, MD R. V. Sondekoppam, MBBS, MD J. Jenkin Tsui, BSc B. C. H. Tsui, MD (&) Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, AB, Canada e-mail: btsui@ualberta.ca

A rare anatomical variation of the brachial plexus: single cord anomaly.

Anatomical variations of the brachial plexus may be important in regional anesthesia and upper limb procedures. A fused single cord of the brachial plexus, although considered rare, was discovered in 4 Indian male cadavers during the dissection of 90 brachial plexuses. All 4 cases demonstrated deviation from the usual pattern starting at the division of trunks continuing to the formation of cords. The location of these single cords was lateral to the axillary artery instead of the typical perivascular relationship. A fused single cord of brachial plexus might be more common than previously thought. The impact on the performance or success of blockade remains unknown.

Pain and inflammatory response following off-pump coronary artery bypass grafting.

Purpose of review Inflammation and pain are two common clinical issues following cardiac surgery, which are important to patient outcomes. This article reviews the literature regarding inflammation and pain following cardiac surgery with special emphasis on off-pump cardiac surgery. Recent findings Off-pump surgery is associated with decreased intraoperative inflammatory response compared with procedures using cardiopulmonary bypass; however, the postoperative pattern of inflammatory response is similar to on-pump procedures. Multimodal analgesic regimens and protocol-based approaches to pain management improve analgesia compared to conventional approaches. Summary Off-pump cardiac surgeries although known to decrease the inflammatory burden do not appear to impact the overall patient outcomes. Recent evidence indicates the prothrombotic tendency following off-pump procedures, which could be related to the time course of inflammation following off-pump cardiac surgery. There might be some benefit of off-pump procedures regarding neurological and renal function that needs further studies. Pain management following off-pump procedures is similar to that of patients undergoing on-pump cardiac surgery. Better caregiver and patient education is crucial for improving pain control following cardiac surgery. Analgesic regimens need to consider adjuvants and regional analgesic techniques and patient-controlled modalities while providing care.

Proper use and interpretation of diaphragmatic ultrasonography.

To the Editor, We read with interest the technical description by ElBoghdadly et al. regarding the utility of ultrasound scanning as part of the assessment of diaphragmatic function after brachial plexus blockade. We are appreciative of their admission regarding the novelty of our previously described ABCDE plus sniff technique and their decision to emulate it as part of their attempt ‘‘to further simplify diaphragm ultrasonography’’ by ‘‘using simple surface marking’’. Unfortunately, their description neglects the importance of the systematic ‘‘step by step’’ approach we outlined. They also incorrectly claim that gross caudal movement of the pleural line can reliably be used to detect diaphragmatic paralysis. To appreciate the pros and cons of each approach more fully, however, it is important to show clearly where one technique ends and the other begins. Although not cited in their article, the basis for our use of the sniff test and El-Boghdadly et al.’s use of surface markings primarily stem from the original concept of the ‘‘ABCDE’’ approach, a mnemonic aid for locating ideal scanning sites to evaluate the diaphragm via intercostal windows rather than hepatic or splenic windows. It involves placing the ultrasound probe at the (A)nterior axillary line just below the level of the nipple, identifying pleural/lung sliding during (B)reathing, and moving the probe in a (C)audal direction along the axillary line until the (D)iaphragm can be identified and (E)valuated. This mnemonic method utilizes step-by-step landmarking of readily recognizable features, such as lung sliding or movement of the pleural line, to locate the diaphragmatic muscle, which is the primary area of interest. It seems that El-Boghdadly et al. intended to describe a new technique of their own by eliminating these systematic steps from the ABC approach advocating only probe placement at ribs 78 (right) or ribs 8-9 (left). By following this course, however, they may have unknowingly reported a technique with a starting location similar to that described by Sarwal et al. More importantly, we question their claim that assessment of diaphragmatic function can be based on the indirect evidence of pleural movement. This approach based on an indirect inference made from pleural movement, rather than direct visualization of changes in diaphragmatic muscle thickness is not only susceptible to physiological artefacts, it is subject to the variability of the patient’s respiratory effort. Generation of tidal volume and associated pleural movement seen on ultrasonography is the net result of the actions of all inspiratory muscle groups, abdominal muscle groups, and rib cage movement. It does not measure the individual contribution of any single muscle group. Hence, the caudal extent of the pleural line does not necessarily correlate with diaphragmatic function in the setting of either acute (Figure) or chronic paralysis. Thus, measurement of muscular thickness has been considered to be sensitive and specific for assessing diaphragmatic function. We recently performed a pilot study that showed that the newly described ABCDE approach provided easy This letter is accompanied by a reply. Please see Can J Anesth 2017; 64: this issue.

Comparative evaluation of the visibility and block characteristics of a stimulating needle and catheter vs an echogenic needle and catheter for sciatic nerve block with a low-frequency ultrasound probe

BACKGROUND Clear visibility of the needle and catheter tip is desirable to perform safe and successful ultrasound-guided peripheral nerve blocks. This can be challenging with deeper blocks in obese patients. This study compared the visibility of echogenic and non-echogenic block needles and catheters in proximal sciatic blocks when performed with a low-frequency curved probe. METHODS Seventy-eight patients undergoing total knee joint arthroplasty were randomized to receive an ultrasound-guided continuous sciatic nerve block using either a non-echogenic needle and stimulating catheter or an echogenic needle and echogenic non-stimulating catheter. Block needles in both groups were placed using both neurostimulation and ultrasound guidance, after which the catheter was positioned using either neurostimulation alone (Stimulating group) or imaging alone (Echogenic group). Three anaesthetists blinded to group allocation graded video clips recorded during the blocks for nerve, needle and catheter visibility. Performance characteristics and block parameters were also compared. RESULTS No significant differences between the two groups were observed with regard to needle or catheter visibility (P=0.516). The Stimulating group required more needle redirections (P=0.009), had a longer procedure time [Echogenic median 274 s vs Stimulating 344 s (P=0.016)], and resulted in greater patient discomfort (P=0.012). There were no significant differences between the two groups in terms of block onset or completion time. CONCLUSIONS Use of echogenic needles and catheters reduced procedure time and patient discomfort compared with a stimulating catheter system. There were no differences in the visibility scores of the two systems. CLINICAL TRIAL REGISTRATION CTR Protocol ID: R-11-495, Clinical Trials.Gov ID: NCT 01492660.

Intracatheter air in continuous thoracic paravertebral block: distraction or assistance?

To the Editor, Non-neuraxial techniques, such as bilateral paravertebral blocks (PVB), are increasingly offered for abdominal surgeries where identification of the catheter tip improves safety and efficacy. A variety of techniques (e.g., fluid, air, or colour Doppler have been described to locate the needle or catheter tip, each with its own advantages and drawbacks. We describe a case of bilateral PVB wherein intracatheter air was visualized on initial injection under ultrasound, localizing the catheter tip. A 46-yr-old female patient (weight, 66 kg; height, 158 cm) scheduled for laparotomy consented to bilateral PVB for postoperative analgesia. After positioning the patient prone, a pre-procedural scan with a linear probe (7-13 MHz, SonoSite M-turbo, Bothel, WA, USA) identified the T8-9 paravertebral space (PVS) bilaterally. Using sterile precautions, continuous PVB was performed using Sonocurl catheters (Sonolong, Sonocurl 100, Pajunk Medizintechnologie GmbH, Geisingen, Germany). The blocks were performed using an intercostal approach with the needle inserted in plane from lateral to medial. The needle tip was identified in the PVS by observing the displacement of pleura with injection of 3 mL of 5% dextrose. The catheter was introduced without real-time ultrasound guidance until it extended 4 cm into the space. Next, 0.5% ropivacaine 20 mL was injected in small aliquots while observing for drug delivery under ultrasound. At the start of injection, we observed air inside the catheter being displaced, confirming catheter tip location within the PVS (Figure, Panels A and B). We further confirmed drug delivery using colour Doppler and pleural displacement. A postoperative chest x-ray also showed the catheter tip in the paravertebral area on magnification (Figure, Panel C). Air used as a contrast to identify the catheter tip is well described for extremity nerve blocks, but such descriptions are uncommon for truncal blocks. Hydro location is useful when the surrounding tissue, i.e., nerves and fascia, are hyperechoic or isoechoic, giving a clear contrast for the fluid, but PVS appears hypoechoic. Hence, liquids may not provide the required discriminative characteristics to locate the catheter tip. Although air is hypoechoic, its deposition around the catheter tip can provide better surrounding contrast to make the tip visible. We deliberately avoided injecting additional air to prevent difficulties in making further block attempts, if needed. While radiological confirmation of catheter tip location is common practice, confirming the catheter tip location while performing the block can avoid unnecessary exposure to radiation. Further studies are needed to evaluate the utility of this technique. There is no foolproof method to identify the catheter tip in the PVS, especially with interference from pleural movements with colour Doppler. Clinicians often have to rely on pleural displacement resulting from injection of a drug. Use of the sonocurl pigtail catheter likely allowed the catheter to remain in the intercostal space once it was inserted, thus facilitating insonation of the catheter tip. In summary, there are multiple recognized techniques to locate the position of the catheter tip for continuous PVB, and intracatheter air may serve as an additional tool for this purpose. Electronic supplementary material The online version of this article (doi:10.1007/s12630-013-9969-8) contains supplementary material, which is available to authorized users.