Continuous Transversus Abdominis Plane Block for Primary Open Inguinal Hernia Repair: A Randomized, Double-Blind, Placebo-Controlled Trial

OBJECTIVE

Patients undergoing open inguinal hernia repair may experience moderate to severe postoperative pain. We assessed opioid consumption in subjects who received a continuous transversus abdominis plane block in addition to standard multimodal analgesia.

DESIGN

Randomized, double-blind, placebo-controlled.

SETTING

Tertiary academic medical center.

SUBJECTS

Adult patients undergoing open inguinal hernia repair at Virginia Mason Medical Center. A total of 90 patients were enrolled.

METHODS

Subjects presenting for surgery were randomized to receive either a continuous transversus abdominis plane block or a subcutaneous sham block. The primary outcome was opioid consumption within the first 48 hours after surgery. Secondary outcomes included pain scores, activities assessment scores, and opioid-related adverse events. Multimodal analgesia utilized in both groups included acetaminophen, nonsteroidal anti-inflammatory drugs, and surgical local anesthetic infiltration.

RESULTS

Eighty-two subjects, 42 from the block group and 40 from the sham group, completed the study, per protocol. The intention-to-treat analysis demonstrated no difference in 48-hour postoperative oxycodone equivalent consumption between the block and sham groups (27.8 mg ± 26.8 vs 32 mg ± 39.2, difference -4.4 mg, P = 0.55). There was a statistically significant reduction in pain scores at 24 hours in the block group. There were no other differences in secondary outcomes.

CONCLUSIONS

Continuous transversus abdominis plane blocks provide modest improvements in pain after open inguinal hernia repair but fail to significantly reduce opioid consumption or improve functional activity levels in the setting of multimodal analgesia use.

A pragmatic approach to evaluating new techniques in regional anesthesia and acute pain medicine

Anesthesiologists set up regional anesthesia and acute pain medicine programs in order to improve the patient outcomes and experience. Given the increasing frequency and volume of newly described techniques, applying a pragmatic framework can guide clinicians on how to critically review and consider implementing the new techniques into clinical practice. A proposed framework should consider how a technique: increases access; enhances efficiency; decreases disparities and improves outcomes. Quantifying the relative contribution of these four factors using a point system, which will be specific to each practice, can generate an overall scorecard to help clinicians make decisions on whether or not to incorporate a new technique into clinical practice or replace an incumbent technique within a clinical pathway.

Comparison of Anterior Suprascapular, Supraclavicular, and Interscalene Nerve Block Approaches for Major Outpatient Arthroscopic Shoulder Surgery

Background

The interscalene nerve block provides analgesia for shoulder surgery, but is associated with diaphragm paralysis. One solution may be performing brachial plexus blocks more distally. This noninferiority study evaluated analgesia for blocks at the supraclavicular and anterior suprascapular levels, comparing them individually to the interscalene approach.

Methods

One hundred-eighty-nine subjects undergoing arthroscopic shoulder surgery were recruited to this double-blind trial and randomized to interscalene, supraclavicular, or anterior suprascapular block using 15 ml, 0.5% ropivacaine. The primary outcome was numeric rating scale pain scores analyzed using noninferiority testing. The predefined noninferiority margin was one point on the 11-point pain scale. Secondary outcomes included opioid consumption and pulmonary assessments.

Results

All subjects completed the study through the primary outcome analysis. Mean pain after surgery was: interscalene = 1.9 (95% CI, 1.3 to 2.5), supraclavicular = 2.3 (1.7 to 2.9), suprascapular = 2.0 (1.4 to 2.6). The primary outcome, mean pain score difference of supraclavicular–interscalene was 0.4 (–0.4 to 1.2; P = 0.088 for noninferiority) and of suprascapular–interscalene was 0.1 (–0.7 to 0.9; P = 0.012 for noninferiority). Secondary outcomes showed similar opioid consumption with better preservation of vital capacity in the anterior suprascapular group (90% baseline [P < 0.001]) and the supraclavicular group (76% [P = 0.002]) when compared to the interscalene group (67%).

Conclusions

The anterior suprascapular block, but not the supraclavicular, provides noninferior analgesia compared to the interscalene approach for major arthroscopic shoulder surgery. Pulmonary function is best preserved with the anterior suprascapular nerve block.

Successful Continuous Adductor Canal Block Placement in a Patient With Absent Sartorius Muscle: A Case Report

We report a novel case of a patient who presented for elective total knee arthroplasty and had distorted adductor canal anatomy due to previous sartorius rotational flap surgery. Despite the lack of a sartorius muscle on the intended operative limb, we describe the successful placement of a continuous adductor canal block. This case is a clinically relevant example that highlights the importance of the vastoadductor membrane as the anatomical anteromedial boundary for the adductor canal, and that it remains intact even after sartorius muscle flap surgery.

The Effect of Fixation Technique on Continuous Interscalene Nerve Block Catheter Success: A Randomized, Double-Blind Trial

BACKGROUND

Continuous peripheral nerve blocks offer advantages over single-injection blocks, including extended analgesia and reduction in opioid consumption. These benefits require that the perineural catheter remain intact for the duration of the planned local anesthetic infusion. Mechanical displacement of catheters, leaking, and consequent failure are known complications. The aim of this study was to evaluate continuous perineural catheter tip-to-nerve apposition in vivo over 48 hours comparing 2 different simple fixation strategies.

METHODS

Subjects presenting for a continuous interscalene nerve block were randomized to perineural catheter fixation with 1 of 2 types of adhesive: Dermabond (2-octylcyanoacrylate) or Mastisol (alcohol 23A, gum mastic, storax, and methyl salicylate), covered with a simple transparent dressing. The primary outcome was the evaluation of catheter-to-nerve apposition maintenance over 48 hours via both a blinded ultrasound evaluation of local anesthetic distribution and a blinded clinical assessment. Secondary outcomes included leakage at the catheter site, pain scores, opioid consumption, catheter-to-skin migration at the insertion site, and patient satisfaction.

RESULTS

Sixty-six subjects were recruited and randomized to compare adhesive group catheter tip-to-nerve apposition on postoperative day 2 (POD 2). Within the intention-to-treat cohort, a statistically significant decrease of perineural catheter tip-to-nerve apposition in the Mastisol group (64.7%) compared with the Dermabond group (90.6%) on POD 2 (odds ratios [OR] 0.19; 95% confidence interval [CI] 0.05-0.75; P = .012) was observed. Similar results were observed on POD 1 (OR 0.19; 95% CI 0.03-1.38; P = NS) and POD 2 (OR 0.14; 95% CI 0.02-0.97; P = .008) within the as-treated cohort. Catheter leakage (OR 67; 95% CI 7.3-589) and median catheter migration difference at the skin insertion site (2.0 cm; 95% CI 0.5-2.5) were also significantly greater in the Mastisol group than in the Dermabond group from POD 0 to POD 2 (P < .001). Median postoperative opioid consumption difference in morphine equivalents (3.2 mg; 95% CI - 9.0 to 14.2) was not significantly different between the Dermabond and the Mastisol groups through POD 2 (P = .542).

CONCLUSIONS

Perineural catheter fixation with Dermabond in continuous interscalene nerve block improves maintenance of catheter-to-nerve apposition when compared with Mastisol.

Ultrasound-Guided Suprainguinal Fascia Iliaca Technique Provides Benefit as an Analgesic Adjunct for Patients Undergoing Total Hip Arthroplasty

Analgesia after total hip arthroplasty is often accomplished by the fascia iliaca compartment block, traditionally performed below the inguinal ligament, to anesthetize both femoral and lateral femoral cutaneous nerves. The course of the lateral femoral cutaneous nerve below the inguinal ligament is variable as opposed to consistent above the inguinal ligament in the pelvis. In this case series including 5 patients, we demonstrate that an ultrasound-guided suprainguinal fascia iliaca approach would consistently anesthetize the lateral femoral cutaneous nerve along with anterior cutaneous femoral nerve branches and provide cutaneous analgesia after total hip arthroplasty, as shown by decreased opioid consumption.

Reduced Length of Hospitalization in Primary Total Knee Arthroplasty Patients Using an Updated Enhanced Recovery After Orthopedic Surgery (ERAS) Pathway

Decreasing hospital length of stay may attenuate costs associated with total knee arthroplasty. The purpose of this study was to determine if updates to an existing orthopedic enhanced recovery after surgery (ERAS) pathway would improve length of hospitalization. Clinical and demographic data were collected on 252 primary total knee arthroplasties between January 2012 and July 2013. Pre-updated and post-updated ERAS pathway cohorts were analyzed for length of stay, clinical outcomes, and re-admissions. The mean length of stay decreased from 76.6 hours to 56.1 hours after implementation of the evidence-based orthopedic enhanced recovery after surgery pathway (P<0.001). This improvement was possible without a concomitant increase in readmission rates.

Processed electroencephalogram during donation after cardiac death

We present a case series of increased bispectral index values during donation after cardiac death (DCD). During the DCD process, a patient was monitored with processed electroencephalogram (EEG), which showed considerable changes traditionally associated with lighter planes of anesthesia immediately after withdrawal of care. Subsequently, to validate the findings of this case, processed EEG was recorded during 2 other cases in which care was withdrawn without the use of hypnotic or anesthetic drugs. We found that changes in processed EEG immediately after withdrawal of care were not only reproducible, but can happen in the absence of changes in major electromyographic or electrocardiographic artifact. It is well documented that processed EEG is prone to artifacts. However, in the setting of DCD, these changes in processed EEG deserve some consideration. If these changes are not due to artifact, dosing of hypnotic or anesthetic drugs might be warranted. Use of these drugs during DCD based primarily on processed EEG values has never been addressed.

Perspectives on Sedation Assessment in Critical Care

Multiple studies have been undertaken to show that neurofunction monitors can correlate to objective sedation assessments. Showing a correlation between these 2 patient assessments tools may not be the correct approach for validation of neurofunction monitors. Two different methods of assessing 2 different modes of the patient’s response to sedation should not be expected to precisely correlate unless the desire is to replace one method with the other. We provide a brief summary of several sedation scales, physiologic measures and neurofunction monitoring tools, and correlations literature for bispectral index monitoring, and the Ramsay Scale and the Sedation Agitation Scale. Neurofunction monitors provide near continuous information about a different domain of the sedation response than intermittent observational assessments. Further research should focus on contributions from this technology to the improvement of patient outcomes when neurofunction monitoring is used as a complement, not a replacement, for observational methods of sedation assessment.

Natural variation of equine infectious anemia virus Gag protein cytotoxic T lymphocyte epitopes

Two defined cytotoxic T lymphocyte (CTL) epitopes from equine infectious anemia virus (EIAV)-infected horses, equine leukocyte alloantigen (ELA)-A5.1-restricted epitope 18a, and ELA-A9-restricted epitope 28b-1 were evaluated for conservation among three wild-type EIAV strains. Epitope 18a variation occurred in all three wild-type EIAV strains, while epitope 28b-1 varied in one strain. Further, 12% amino acid changes occurred in the Gag proteins of a recently isolated wild-type strain, documenting a much greater Gag protein variation than previously reported. Evaluation of epitope 18a among two virus isolates from sequential disease episodes in a single horse, H513 (ELA-A5.1/A8), demonstrated that no variation that affected CTL recognition occurred. H513 PBMC had CTLm to epitope 18a before the occurrence of disease episodes caused by viruses expressing epitope 18a; however, the frequencies were low (5-15/10(6) PBMC). Later in infection there was an absence of disease episodes associated with an increase in CTLm frequency to EIAV(WSU5)-infected targets, but not epitope 18a-pulsed targets. Therefore, if CTLm to EIAV epitopes were involved in maintaining the carrier state in H513, they recognized epitopes other than 18a.