The effects of intrathecal morphine on urinary bladder function and recovery in patients having a cesarean delivery - A randomized clinical trial

INTRODUCTION

Spinal anesthesia with intrathecal morphine (ITM) is a common anesthesia technique for cesarean delivery. The hypothesis was that the addition of ITM will delay micturition in women undergoing cesarean delivery.

METHODS

Fifty-six ASA physical status I and II women scheduled to undergo elective cesarean delivery under spinal anesthesia were randomized to the PSM group (50 mg prilocaine + 2.5 mcg sufentanil + 100 mcg morphine; n = 30) or PS group (50 mg prilocaine + 2.5 mcg sufentanil; n = 24). The patients in the PS group received a bilateral transverse abdominal plane (TAP) block. The primary outcome was the effect of ITM on the time to micturition and the secondary outcome was the need for bladder re-catheterization.

RESULTS

The time to first urge to urinate (8 [6-10] hours in the PSM group versus 6 [4-6] hours in the PS group) and the time to first micturition (10 [8-12] hours in the PSM group versus 6 [6-8] hours in the PS group) were significantly (p < 0.001) prolonged in the PSM group. Two patients in the PSM group met the 800 mL criterium for urinary catheterization after 6 and 8 h respectively.

CONCLUSION

This study is the first randomized trial to demonstrate that the addition of ITM to the standardized mixture of prilocaine and sufentanil significantly delayed micturition.

The effect of spinal versus general anaesthesia on perioperative muscle weakness in patients having bilateral total hip arthroplasty: a single center randomized clinical trial

BACKGROUND

Perioperative neuro-endocrine stress response may contribute to acquired muscle weakness. Regional anaesthesia has been reported to improve the outcome of patients having total hip arthroplasty. In this study, it was hypothesized that spinal anaesthesia (SA) decreases the perioperative neuro-endocrine stress response and perioperatively acquired muscle weakness (PAMW), as compared to general anaesthesia (GA).

METHODS

Fifty subjects undergoing bilateral total hip arthroplasty (THA) were randomly allocated to receive a standardized SA (n = 25) or GA (n = 25). Handgrip strength was assessed preoperatively, on the first postoperative day (primary endpoint) and on day 7 and 28. Respiratory muscle strength was measured by maximal inspiratory pressure (MIP). Stress response was assessed by measuring levels of Adrenocorticotropic hormone (ACTH), cortisol and interleukin-6 (IL-6).

RESULTS

Handgrip strength postoperatively (day 1) decreased by 5.4 ± 15.9% in the SA group, versus 15.2 ± 11.7% in the GA group (p = 0.02). The handgrip strength returned to baseline at day 7 and did not differ between groups at day 28. MIP increased postoperatively in patients randomized to SA by 11.7 ± 48.3%, whereas it decreased in GA by 12.2 ± 19.9% (p = 0.04). On day 7, MIP increased in both groups, but more in the SA (49.0 ± 47.8%) than in the GA group (14.2 ± 32.1%) (p = 0.006). Postoperatively, the levels of ACTH, cortisol and IL-6 increased in the GA, but not in the SA group (p < 0.004).

CONCLUSION

In patients having bilateral THA, SA preserved the postoperative respiratory and peripheral muscle strength and attenuated the neuro-endocrine and inflammatory responses.

TRIAL REGISTRATION

clinicaltrials.gov NCT03600454.

A novel infrapatellar approach of ultrasound-guided intra-articular injection of the knee from both lateral and medial side: a case series

Knee osteoarthritis (OA) is common. Ultrasound-guided intra-articular injection (UGIAI) using the superolateral approach is currently the gold standard for treating knee OA, but it is not 100% accurate, especially in patients with no knee effusion. Herein, we present a case series of chronic knee OA treated with a novel infrapatellar approach to UGIAI. Five patients with chronic grade 2-3 knee OA, who had failed on conservative treatments and had no effusion but presented with osteochondral lesions over the femoral condyle, were treated with UGIAI with different injectates using the novel infrapatellar approach. The first patient was initially treated using the traditional superolateral approach, but the injectate was not delivered intra-articularly and became trapped in the pre-femoral fat pad. The trapped injectate was aspirated in the same session due to interference with knee extension, and the injection was repeated using the novel infrapatellar approach. All patients who received the UGIAI using the infrapatellar approach had the injectates successfully delivered intra-articularly, as confirmed with dynamic ultrasound scanning. Their Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, stiffness, and function scores significantly improved 1 and 4 weeks post-injection. UGIAI of the knee using a novel infrapatellar approach is readily learned and may improve accuracy of UGIAI, even for patients with no effusion.

Motor-Sparing Nerve Blocks Can Improve the Results of Digit Tendon Surgery: A Case Report

A 56-year-old woman presented with flexion dysfunction of the fifth digit 6 weeks after surgical repair of a flexor digitorum profundus laceration. She was scheduled for surgical adhesiolysis and restoration of the functionality of the finger. Intraoperative monitoring of the range of motion by active flexion was deemed important to prevent incomplete release of the tendon and residual dysfunction. Distal median and ulnar nerve blocks were used for anesthesia with the patient's ability to flex the finger. This case suggests that motor-sparing peripheral nerve blocks can improve functional outcome in certain hand surgeries.

Effect of Lidocaine 2% Versus Bupivacaine 0.5% and 1 Versus 2 Dual Separate Injections on Onset and Duration of Ultrasound-Guided Wrist Blocks: A Blinded 2 × 2 Factorial Randomized Clinical Trial

BACKGROUND

Local anesthetics are often selected or mixed to accomplish faster onset of anesthesia. However, with ultrasound guidance, local anesthetics are delivered with greater precision, which may shorten the onset time with all classes of local anesthetics. In this study, we compared onset time and duration of ultrasound-guided wrist blocks with a fast onset versus a longer lasting local anesthetic administered via single or dual (spatially separate) injections at the level of the midforearm.

METHODS

In this randomized clinical trial, 36 subjects scheduled for carpal tunnel release were randomly assigned to receive ultrasound-guided median and ulnar nerve blocks with lidocaine 2% or bupivacaine 0.5% via single or dual injections (n = 9 in each group). Subjects fulfilled the study requirements. The main outcome variables were onset and duration of sensory blockade, which were tested separately in 2 (drug) × 2 (injection) analysis of variances (ANOVAs) with interaction terms.

RESULTS

Sensory block onset time did not differ significantly between subjects given lidocaine 2% (9.2 ± 3.4 minutes) or bupivacaine 0.5% (9.5 ± 3.1 minutes) (P = .76; mean difference, -0.3 ± 1.1 minutes [95% confidence interval {CI}, -2.5 to 1.9]) or between the single- (9.6 ± 2.8 minutes) and dual- (9.1 ± 3.6 minutes) injection groups (P = .69; mean difference, -0.4 ± 1.1 minutes [95% CI, -1.8 to 2.6]). Sensory duration was longer for subjects in the bupivacaine 0.5% group (27.3 ± 11.6 hours) than for subjects in the lidocaine 2% group (8.4 ± 4.1 hours) (P < .001; 95% CI, 12.7-25.1). However, sensory duration in the single- (15.7 ± 12.5 hours) and dual- (19.4 ± 13.1 hours) injection groups did not differ significantly (P = .28; mean difference, -3.7 ± 4.3 hours [95% CI, -12.6 to 5.1]).

CONCLUSIONS

No significant effect was found for onset time between lidocaine 2% and bupivacaine 0.5% used in ultrasound-guided wrist blocks. Dual injections did not shorten onset time. Since mean nerve block duration was longer with bupivacaine 0.5%, our results suggest that the selection of local anesthetic for the median and ulnar nerves at the level of the midforearm should be based on the desired duration of the block and not on its speed of onset.

Standardizing nomenclature in regional anesthesia: an ASRA-ESRA Delphi consensus study of abdominal wall, paraspinal, and chest wall blocks

BACKGROUND

There is heterogeneity in the names and anatomical descriptions of regional anesthetic techniques. This may have adverse consequences on education, research, and implementation into clinical practice. We aimed to produce standardized nomenclature for abdominal wall, paraspinal, and chest wall regional anesthetic techniques.

METHODS

We conducted an international consensus study involving experts using a three-round Delphi method to produce a list of names and corresponding descriptions of anatomical targets. After long-list formulation by a Steering Committee, the first and second rounds involved anonymous electronic voting and commenting, with the third round involving a virtual round table discussion aiming to achieve consensus on items that had yet to achieve it. Novel names were presented where required for anatomical clarity and harmonization. Strong consensus was defined as ≥75% agreement and weak consensus as 50% to 74% agreement.

RESULTS

Sixty expert Collaborators participated in this study. After three rounds and clarification, harmonization, and introduction of novel nomenclature, strong consensus was achieved for the names of 16 block names and weak consensus for four names. For anatomical descriptions, strong consensus was achieved for 19 blocks and weak consensus was achieved for one approach. Several areas requiring further research were identified.

CONCLUSIONS

Harmonization and standardization of nomenclature may improve education, research, and ultimately patient care. We present the first international consensus on nomenclature and anatomical descriptions of blocks of the abdominal wall, chest wall, and paraspinal blocks. We recommend using the consensus results in academic and clinical practice.

Quadratus lumborum block: an imaging study of three approaches

BACKGROUND AND OBJECTIVES

Different injection techniques for the quadratus lumborum (QL) block have been described. Data in human cadavers suggest that the transverse oblique paramedian (TOP) QL3 may reach the thoracic paravertebral space more consistently than the QL1 and QL2. However, the distribution of injectate in cadavers may differ from that in patients. Hence, we assessed the distribution of the injectate after the QL1, QL2, and TOP QL3 techniques in patients.

MATERIALS AND METHODS

Thirty-four patients scheduled for abdominal surgery received QL blocks postoperatively; 26 patients received bilateral and 8 patients received unilateral blocks. Block injections were randomly allocated to QL1, QL2, or TOP QL3 techniques (20 blocks per each technique). The injections consisted of 18 mL of ropivacaine 0.375% with 2 mL of radiopaque contrast, injected lateral or posterior to the QL muscle for the QL1 and QL2 techniques, respectively. For the TOP QL3, the injection was into the plane between the QL and psoas muscles, proximal to the L2 transverse process. Two reviewers, blinded to the allocation, reviewed three-dimensional computed tomography (3D-CT) images to assess the distribution of injectate.

RESULTS AND DISCUSSION

The QL1 block spread in the transversus abdominis plane (TAP), QL2 in the TAP, and posterior aspect of the QL muscle, whereas TOP QL3 spread consistently in the anterior aspect of the QL muscle with occasional spread to the lumbar and thoracic paravertebral areas.

CONCLUSIONS

The spread of injectate after QL1, QL2, and QL3 blocks, resulted in different distribution patterns, primarily in the area of injection. The TOP QL3 did not result in consistent interfascial spread toward the thoracic paravertebral space.

A100 ORAL VANCOMYCIN THERAPY FOR CLOSTRIDIOIDES DIFFICILE INFECTION AND RISK OF INFECTION WITH GRAM-NEGATIVE ORGANISMS

Background

Vancomycin is the recommended first-line therapy for mild to severe Clostridioides difficile infection (CDI). However, oral vancomycin is associated with disruption of the indigenous microbiota, predisposing patients to overgrowth of endogenous pathogens such as vancomycin-resistant enterococci.

Aims

The primary objective of the study is to examine the effect of the treatment regimens of CDI on the risk of infection with gram-negative organisms in adult patients treated for CDI.

Methods

A retrospective cohort study of 319 adult patients treated for CDI at Hamilton Health Sciences in the year 2015. A multivariate logistic regression analysis was performed to determine if oral vancomycin-based therapy is associated with an increased risk of infection with gram-negative organisms after adjustment for other factors.

Results

Eighty-one patients were excluded because of recurrent episodes of CDI within the same year or missing information. 238 patients were included in the final analysis. 48 (20.2%) patients had positive culture for gram-negative organisms after onset of CDI. Urine was the most common source for gram-negative organisms (39/48, 81.3%) followed by blood (8/48,16.7%). The most common isolated gram-negative organisms were Escherichia coli (18/48, 37.5%) and Klebsiella pneumonia (9/48, 18.8%).

The most common CDI treatment regimens were metronidazole monotherapy (137/238, 57.6%), vancomycin monotherapy (13/238, 5.5%), and combination therapy (88/238, 37.0%). Among patients who were treated with metronidazole monotherapy, vancomycin monotherapy, and combination therapy, 30(30/137, 21.9%), 3 (3/13,23.1%), and 15 (15/88, 17.1%) had positive culture for gram-negative organisms, respectively (P= 0.6).

Ninety-seven (97/238,40.8%) patients had severe CDI, 40 (40/97, 41.2%) were treated with metronidazole monotherapy, 5(5/97, 5.2%) with vancomycin monotherapy, and 52 (52/97, 53.6%) with combination therapy. 26 (26/141,18.4%) and 22 (22/97, 22.7%) had positive culture for gram-negative organisms among patients with non-severe and severe CDI, receptively (P= 0.7). In the multivariate analysis, neither type of CDI treatment regimen (P=0.2, 95% CI 0.30–1.31) nor CDI severity (P=0.4, 95% CI 0.67–2.69) was associated an increased risk of infection with gram-negative organisms after CDI onset.

Conclusions

Contrary to the reported literature, we did not find that oral vancomycin-based CDI treatment was associated with increased risk of infection with gram-negative organisms.

Funding Agencies

None

Peripheral nerve catheters: A critical review of the efficacy

Continuous peripheral nerve blocks are commonly used for postoperative analgesia after surgery. However, catheter failure may occur due to either primary (incorrect insertion) or secondary reasons (displacement, obstruction, disconnection). Catheter failure results in unanticipated pain, need for opioid use, and risk of readmission or delay in hospital discharge. This review aimed to assess definition and frequency of catheter failure, and discuss the alternatives to prolong duration of single-shot nerve blocks. A literature search was performed on peripheral catheters reporting failure as the main outcome measure. Thirty-three studies met the selection criteria, comprising 2711 catheters. Literature review suggests that peripheral nerve catheters have clinically significant failure rate when the assessment is performed using an objective (imaging) method. Subjective methods of assessment (without imaging) may underestimate the incidence of catheter failure.

Supra-inguinal injection for fascia iliaca compartment block results in more consistent spread towards the lumbar plexus than an infra-inguinal injection: a volunteer study

BACKGROUND AND OBJECTIVES

Lumbar plexus block has been used to provide postoperative analgesia after lower limb surgery. The fascia iliaca compartment block (FICB) has been proposed as an anterior approach of the lumbar plexus targeting the femoral, obturator and lateral femoral cutaneous nerve. However, both radiological and clinical evidence demonstrated that an infra-inguinal approach to the fascia iliaca compartment does not reliably block the three target nerves.We hypothesized that a supra-inguinal approach of the fascia iliaca compartment results in a more consistent block of the three target nerves than an infra-inguinal approach.

METHODS

We performed a randomized controlled, double-blind trial in 10 healthy volunteers. Both an infra-inguinal FICB (I-FICB) and a supra-inguinal FICB (S-FICB) were performed on the left or the right side in each volunteer. Forty milliliters of lidocaine 0.5% was injected with each approach. Sensory and motor block and spread of local anesthetics (LA) on MRI were assessed.

RESULTS

After an S-FICB, 80% of the volunteers had a complete sensory block of the medial, anterior and lateral region of the thigh, compared with 30% after an I-FICB (p=0.035). There was an insignificant effect on motor function with both approaches. After an S-FICB, in 8 out of 10 volunteers there was spread of LA in the expected anatomic location of the obturator nerve on MRI compared with 1 out of 10 volunteers after an I-FICB (p=0.0017). The cranial spread of LA after an S-FICB on MRI was higher than after an I-FICB (p=0.007), whereas there was a more caudal spread of LA on MRI after an I-FICB than after an S-FICB (p=0.005).

CONCLUSIONS

An S-FICB produces a more complete sensory block of the medial, anterior and lateral region of the thigh, compared with an I-FICB. Our study demonstrates that an S-FICB with 40 mL of LA more reliably spreads LA to the anatomical location of the three target nerves of the lumbar plexus on MRI than an I-FICB. An S-FICB also leads to a more consistent spread in a cranial direction under the fascia iliaca and around the psoas muscle.

CLINICAL TRIAL REGISTRATION

This work was registered with the European clinical trial registry: Identifier Eudra CT 2015-004607-24.

A Prospective Randomized Study to Evaluate a New Learning Tool for Ultrasound-Guided Regional Anesthesia

Objective

To evaluate the effectiveness of a new learning tool for needle insertion accuracy skills during a simulated ultrasound-guided regional anesthesia procedure.

Methods

Thirty participants were included in this randomized controlled study. After viewing a prerecorded video of a single, discreet, ultrasound-guided regional anesthesia task, all participants performed the same task three consecutive times (pretest), and needle insertion accuracy skills in a phantom model were recorded as baseline. All participants were then randomized into two groups, experimental and control. The experimental group practiced the task using the new tool, designed with two video cameras, a monitor, and an ultrasound machine where the images from the ultrasound and video of hand movements are viewed simultaneously on the monitor. The control group practiced the task without using the new tool. After the practice session, both groups repeated the same task and were evaluated in the same manner as in the pretest.

Results

Participants in both group groups had similar baseline characteristics with respect to previous experience with ultrasound-guided regional anesthesia procedures. The experimental group had significantly better needle insertion accuracy scores ( P  < 0.01) than the control group. Using the new learning tool, inexperienced participants had better needle insertion accuracy scores ( P  < 0.01) compared with experienced participants.

Conclusions

This study demonstrates that the use of this new learning tool results in short-term improvement in hand-eye, motor, and basic needle insertion skills during a simulated ultrasound-guided regional anesthesia procedure vs traditional practice methods. Skill improvement was greater in novices compared with experienced participants.

Impact of volume expansion on the efficacy and pharmacokinetics of liposome bupivacaine

Liposome bupivacaine is a prolonged-release liposomal formulation of bupivacaine indicated for single-dose infiltration into the surgical site to produce postsurgical analgesia of longer duration than traditional local anesthetics. This review summarizes the available data on how volume expansion may impact the analgesic efficacy of liposome bupivacaine. The Phase II and III clinical studies that involved surgical site administration of liposome bupivacaine at various concentrations in different surgical settings revealed no apparent concentration–efficacy relationship. A single-center, prospective study comparing the efficacy of transversus abdominis plane infiltration with liposome bupivacaine administered in a lower (266 mg/40 mL) vs a higher (266 mg/20 mL) dose concentration in subjects undergoing robotic-assisted laparoscopic prostatectomy also reported similar postsurgical pain intensity scores and opioid usage in both treatment groups. The pharmacokinetic profile of liposome bupivacaine following subcutaneous injections in rats was unaltered by differences in drug concentration, dose, or injection volume within the ranges tested. Volume expansion of liposome bupivacaine to a total volume of 300 mL or less does not appear to impact its clinical efficacy or pharmacokinetic profile, thus allowing flexibility to administer the formulation across a wide range of diluent volumes.

Neurotoxicity of perineural vs intraneural-extrafascicular injection of liposomal bupivacaine in the porcine model of sciatic nerve block

Liposomal bupivacaine is a prolonged-release local anaesthetic, the neurotoxicity of which has not yet been determined. We used quantitative histomorphometric and immunohistochemical analyses to evaluate the neurotoxic effect of liposomal bupivacaine after perineural and intraneural (extrafascicular) injection of the sciatic nerve in pigs. In this double-blind prospective randomised trial, 4 ml liposomal bupivacaine 1.3% was injected either perineurally (n = 5) or intraneurally extrafascicularly (n = 5). Intraneural-extrafascicular injection of saline (n = 5) was used as a control. After emergence from anaesthesia, neurological examinations were conducted over two weeks. After harvesting the sciatic nerves, no changes in nerve fibre density or myelin width indicative of nerve injury were observed in any of the groups. Intraneural injections resulted in longer sensory blockade than perineural (p < 0.003) without persistent motor or sensory deficit. Sciatic nerve block with liposomal bupivacaine in pigs did not result in histological evidence of nerve injury.

Pathophysiology and Etiology of Nerve Injury Following Peripheral Nerve Blockade

This review synthesizes anatomical, anesthetic, surgical, and patient factors that may contribute to neurologic complications associated with peripheral nerve blockade. Peripheral nerves have anatomical features unique to a given location that may influence risk of injury. Peripheral nerve blockade-related peripheral nerve injury (PNI) is most severe with intrafascicular injection. Surgery and its associated requirements such as positioning and tourniquet have specific risks. Patients with preexisting neuropathy may be at an increased risk of postoperative neurologic dysfunction. Distinguishing potential causes of PNI require clinical assessment and investigation; a definitive diagnosis, however, is not always possible. Fortunately, most postoperative neurologic dysfunction appears to resolve with time, and the incidence of serious long-term nerve injury directly attributable to peripheral nerve blockade is relatively uncommon. Nonetheless, despite the use of ultrasound guidance, the risk of block-related PNI remains unchanged.

WHAT'S NEW

Since the 2008 Practice Advisory, new information has been published, furthering our understanding of the microanatomy of peripheral nerves, mechanisms of peripheral nerve injection injury, toxicity of local anesthetics, the etiology of and monitoring methods, and technologies that may decrease the risk of nerve block-related peripheral nerve injury.

Ultrasound guided injection inside the common sheath of the sciatic nerve at division level has a higher success rate than an injection outside the sheath

BACKGROUND AND OBJECTIVE

The recommendations for the level of injection and ideal placement of the needle tip required for successful ultrasound-guided sciatic popliteal block vary among authors. A hypothesis was made that, when the local anesthetic is injected at the division of the sciatic nerve within the common connective tissue sheath, the block has a higher success rate than an injection outside the sheath.

METHODS

Thirty-four patients scheduled for hallux valgus repair surgery were randomized to receive either a sub-sheath block (n=16) or a peri-sheath block (n=18) at the level of the division of the sciatic nerve at the popliteal fossa. For the sub-sheath block, the needle was advanced out of plane until the tip was positioned between the tibial and peroneal nerves, and local anesthetic was then injected without moving the needle. For the peri-sheath block, the needle was advanced out of plane both sides of the sciatic nerve, to surround the sheath. Mepivacaine 1.5% and levobupivacaine 0.5% 30mL were used in both groups. The progression of motor and sensory block was assessed at 5min intervals. Duration of block was recorded.

RESULTS

Adequate surgical block was achieved in all patients in the subsheath group (100%) compared to 12 patients (67%) in the peri-sheath group at 30min. Sensory block was achieved faster in the subsheath than peri-sheath (9.1±7.4min vs. 19.0±4.0; p<.001).

CONCLUSIONS

Our study suggests that for successful sciatic popliteal block in less than 30min, local anesthetic should be injected within the sheath.

Incidence of intraneural needle insertion in ultrasound-guided femoral nerve block: a comparison between the out-of-plane versus the in-plane approaches

BACKGROUND

The optimal method of ultrasound-guided femoral nerve block (in-plane vs. out-of-plane) has not been established. We tested the hypothesis that the incidence of needle-nerve contact may be higher with out-of-plane than with in-plane needle insertion.

METHODS

Forty-four patients with hip fracture (American Society of Anaesthesiologists physical status I-III) were randomized to receive the femoral block with an out-of-plane approach (needle inserted at a 45-60° angle 1cm caudal to the midpoint of the ultrasound probe just above the femoral nerve) or with an in-plane technique (needle inserted 0.2-0.4 cm from the side of the probe lateral to the femoral nerve). Data collected included depth of needle insertion, response to nerve electric stimulation, and distribution of the injected volume in relation to the nerve (anterior vs. posterior, the latter assuming needle-nerve contact). The sensory block onset was tested at 20 min and block recovery and any neurologic symptoms were evaluated at 24h.

RESULTS

The incidence of needle-nerve contact was significantly higher with the out-of-plane approach (14/22 patients [64%]) than with the in-plane approach (2/22 patients [9%]) (p<0.001) (OR=17.5, 95% CI: 4-79). The rate of paraesthesia on crossing the fascia iliaca was similar in the two groups. All blocks uneventfully regressed; and no patient developed neurologic symptoms.

CONCLUSIONS

Under the conditions of our study, needle-nerve contact during femoral nerve block occurs frequently with the out-of-plane approach. An in-plane approach results in an equally effective femoral block and less incidence of needle-nerve contact.

Feasibility and analgesic efficacy of the transversus abdominis plane block after single-port laparoscopy in patients having bariatric surgery

Purpose

The transversus abdominis plane (TAP) block is a technique increasingly used for analgesia after surgery on the anterior abdominal wall. We undertook this study to determine the feasibility and analgesic efficacy of ultrasound-guided TAP blocks in morbidly obese patients. We describe the dermatomal spread of local anesthetic in TAP blocks administered, and test the hypothesis that TAP blocks decrease visual analog scale (VAS) scores.

Patients and methods

After ethics committee approval and informed consent, 35 patients with body mass index >35 undergoing single-port sleeve gastrectomy (SPSG) were enrolled. All patients received balanced general anesthesia, followed by intravenous patient-controlled analgesia (IV-PCA; hydromorphone) postoperatively; all reported VAS >3 upon arrival to the recovery room. From the cohort of 35 patients having single-port laparoscopy (SPL), a sealed envelope method was used to randomly select ten patients to the TAP group and 25 patients to the control group. The ten patients in the TAP group received ultrasound-guided TAP blocks with 30 mL of 0.2% Ropivacaine injected bilaterally. The dermatomal distribution of the sensory block (by pinprick test) was recorded. VAS scores for the first 24 hours after surgery and opioid use were compared between the IV-PCA+TAP block and IV-PCA only groups.

Results

Sensory block ranged from T5–L1. Mean VAS pain scores decreased from 8 ± 2 to 4 ± 3 (P=0.04) within 30 minutes of TAP block administration. Compared with patients given IV-PCA only, significantly fewer patients who received TAP block had moderate or severe pain (VAS 4–10) after block administration at 6 hours and 12 hours post-surgery. However, cumulative consumption of hydromorphone at 24 hours after SPSG surgery was similar for both groups.

Conclusion

Ultrasound-guided TAP blocks in morbidly obese patients are feasible and result in satisfactory analgesia following SPSG in the immediate postoperative period.

Use of ultrasound-guided intercostal nerve block as a sole anaesthetic technique in a high-risk patient with Duchenne muscular dystrophy

Duchenne muscular dystrophy is a progressive neuromuscular disease. Mortality is typically related to combined respiratory failure and dilated cardiomyopathy. Surgery under general anesthesia or deep sedation presents increased risks for pulmonary complications or ventilator dependency postoperatively. We describe the utility of ultrasound guided intercostal nerve blocks for surgery on the chest wall in a patient with Duchenne muscular dystrophy and severe respiratory compromise.

Low interscalene block provides reliable anesthesia for surgery at or about the elbow

STUDY OBJECTIVE

To determine whether interscalene brachial plexus block (ISB) provides adequate anesthesia for surgery on or about the elbow.

STUDY DESIGN

Case series.

SETTING

Operating room of an academic teaching hospital.

PATIENTS

78 patients scheduled for elective elbow surgery.

INTERVENTIONS

All patients received an ISB using a low approach technique. A stimulating needle was inserted in the interscalene groove two cm above the clavicle. A volume of 35-45 mL of mepivacaine 1.5% or ropivacaine 0.5% was administered after obtaining a motor response of any component of the brachial plexus with a current intensity of 0.2-0.4 mA (0.1 msec).

MEASUREMENTS

Block success rate, defined as the ability to complete surgery without use of intraoperative opioids or general anesthesia, was assessed. Verbal rating scores for pain (0 = no pain, 10 = worst pain imaginable) were obtained in the recovery room.

MAIN RESULTS

Low ISB resulted in successful surgical anesthesia in 75 (96%) of the study patients. Verbal rating scores were low (0-2) for all patients postoperatively.

CONCLUSIONS

The low interscalene block can be used to provide surgical anesthesia in the majority of patients having surgery on or about the elbow.

Intraneural injection during nerve stimulator-guided sciatic nerve block at the popliteal fossa

BACKGROUND

Exact location of the needle tip during nerve stimulation-guided peripheral nerve blocks is unknown. Using high-frequency ultrasound imaging, we tested the hypothesis that intraneural injection is common with nerve stimulator-guided sciatic nerve (SN) block in popliteal fossa.

METHODS

Forty-two patients scheduled for hallux valgus repair were studied. Sciatic block at the popliteal fossa was accomplished using nerve stimulation. When a motor response was elicited at <0.5 mA (2 Hz, 0.1 ms), 40 ml of local anaesthetic (LA) was injected. Using ultrasound (Titan, Sonosite, 5-10 MHz), the diameters and area of the SN were measured before and after the injection. The presence of nerve swelling and proximal or distal diffusion of LA were also assessed. Intraneural injection was defined as nerve area (NA) increase of > OR =15% and one or more additional ultrasonographic markers (nerve swelling, proximal-distal diffusion within epineural tissue). Clinical neurological evaluation was performed 1 week after the block.

RESULTS

Post-injection NA increase > OR =15% was seen in 32 (76%) patients [0.54 (SD 0.19) cm(-2) vs 0.76 (0.24) cm(-2); P<0.05]. Nerve swelling with fascicular separation was observed in 37 (88%) patients; proximal and distal diffusion of LA were present in six (14%) and 14 (38%) patients, respectively. Intraneural injection criteria were met in 28 (66%) patients. Greater NA increase was present in patients with fast block onset [61 (45) vs 25 (33)%; (Dif 35% 95% CI 61-9%); P<0.05]. No patient developed neurological complications.

CONCLUSIONS

Intraneural (subepineural) injection is a common occurrence after nerve stimulator-guided SN block at the popliteal fossa, yet it may not inevitably lead to neurological complications.

Regional anesthesia in anesthetized or heavily sedated patients

The American Society of Regional Anesthesia and Pain Medicine (ASRA) Practice Advisory on Neurologic Complications in Regional Anesthesia and Pain Medicine includes an evidence- and expert opinion-based section on performing procedures on anesthetized or heavily sedated patients. This practice advisory is based on existing scientific literature, pathophysiological principles, and expert opinion. The advisory panel examined the ability of anesthetized or heavily sedated patients to recognize and report intravascular injection of local anesthetic or impending neurologic injury. The advisory panel also considered whether or not the ability to recognize and report symptoms could actually affect the occurrence of nerve injury or local anesthetic systemic toxicity. The advisory contains recommendations pertaining to both adult and pediatric patients.