Standardizing nomenclature in regional anesthesia: an ASRA-ESRA Delphi consensus study of upper and lower limb nerve blocks

BACKGROUND

Inconsistent nomenclature and anatomical descriptions of regional anesthetic techniques hinder scientific communication and engender confusion; this in turn has implications for research, education and clinical implementation of regional anesthesia. Having produced standardized nomenclature for abdominal wall, paraspinal and chest wall regional anesthetic techniques, we aimed to similarly do so for upper and lower limb peripheral nerve blocks.

METHODS

We performed a three-round Delphi international consensus study to generate standardized names and anatomical descriptions of upper and lower limb regional anesthetic techniques. A long list of names and anatomical description of blocks of upper and lower extremities was produced by the members of the steering committee. Subsequently, two rounds of anonymized voting and commenting were followed by a third virtual round table to secure consensus for items that remained outstanding after the first and second rounds. As with previous methodology, strong consensus was defined as ≥75% agreement and weak consensus as 50%-74% agreement.

RESULTS

A total of 94, 91 and 65 collaborators participated in the first, second and third rounds, respectively. We achieved strong consensus for 38 names and 33 anatomical descriptions, and weak consensus for five anatomical descriptions. We agreed on a template for naming peripheral nerve blocks based on the name of the nerve and the anatomical location of the blockade and identified several areas for future research.

CONCLUSIONS

We achieved consensus on nomenclature and anatomical descriptions of regional anesthetic techniques for upper and lower limb nerve blocks, and recommend using this framework in clinical and academic practice. This should improve research, teaching and learning of regional anesthesia to eventually improve patient care.

Economic Outcomes and Incidence of Postsurgical Hypotension With Liposomal Bupivacaine vs Epidural Analgesia in Abdominal Surgeries

Background: Epidural analgesia can be associated with high costs and postsurgical risks such as hypotension, despite its widespread use and value in providing opioid-sparing pain management. We tested the hypothesis that liposomal bupivacaine (LB) might be a reliable alternative to epidural analgesia in this real-world study. Objectives: To compare economic outcomes and hypotension incidence associated with use of LB and epidural analgesia for abdominal surgery. Methods: This retrospective analysis identified records of adults who underwent abdominal surgeries between January 2016 and September 2019 with either LB administration or traditional epidural analgesia using the Premier Healthcare Database. Economic outcomes included length of stay, hospital costs, rates of discharge to home, and 30-day hospital readmissions. Secondary outcomes included incidence of postsurgical hypotension and vasopressor use. Subgroup analyses were stratified by surgical procedure (colorectal, abdominal) and approach (endoscopic, open). A generalized linear model adjusted for patient and hospital characteristics was used for all comparisons. Results: A total of 5799 surgical records (LB, n=4820; epidural analgesia, n=979) were included. Compared with cases where LB was administered, cases of epidural analgesia use were associated with a 1.6-day increase in length of stay (adjusted rate ratio [95% confidence interval (CI), 1.2 [1.2-1.3]]; P<.0001) and $6304 greater hospital costs (adjusted rate ratio [95% CI], 1.2 [1.2-1.3]]; P<.0001). Cost differences were largely driven by room-and-board fees. Epidural analgesia was associated with reduced rates of discharge to home (P<.0001) and increased 30-day readmission rates (P=.0073) compared with LB. Epidural analgesia was also associated with increased rates of postsurgical hypotension (30% vs 11%; adjusted odds ratio [95% CI], 2.8 [2.3-3.4]; P<.0001) and vasopressor use (22% vs 7%; adjusted odds ratio [95% CI], 3.1 [2.5-4.0]; P<.0001) compared with LB. Subgroup analyses by surgical procedure and approach were generally consistent with overall comparisons. Discussion: Our results are consistent with previous studies that demonstrated epidural analgesia can be associated with higher utilization of healthcare resources and complications compared with LB. Conclusions: Compared with epidural analgesia, LB was associated with economic benefits and reduced incidence of postsurgical hypotension and vasopressor use.

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.

Raman measurements of substrate temperature in a molecular beam epitaxy growth chamber

A method is described for directly measuring the temperature of a substrate in a molecular-beam epitaxy (MBE) growth system. The approach relies on the establishment of the temperature dependence of Raman-active phonons of the substrate material using independently known calibration points across the range of interest. An unknown temperature in this range is then determined based on the Raman peak position with the substrate in situ the MBE chamber. The apparatus relies on conventional optics and Raman components. Shifting and broadening of the Raman spectrum are described based on the effects of thermal expansion and anharmonic decay. The choice of reference temperature is discussed. The method is qualified by examining the substrate temperature dependence, relative to that of a standard thermocouple, during a commonly used ramp procedure. Both temperature difference and time lag are obtained.

Optical, Chemical and Electrical Characterization of Ion-Etched Gallium Arsenide Surfaces

Ultraviolet reflectivity, surface chemistry and electrical measurements are reported for Ar+-ion bombarded (100) GaAs surfaces, with ion energies from 0.5 to 4 keV. Changes in reflectivity spectra, surface stoichiometry and Schottky diode parameters are reported as functions of ion energy.

Pre-Clinical Evaluation of Direct Current Ablation for the Treatment of Benign Prostatic Hyperplasia

Benign Prostatic Hyperplasia (BPH) is a non-cancerous growth of the prostate gland affecting about 50% of the men over age 50. As men age, the prostate continues to grow leading to increased prostate volume, which may cause lower urinary tract symptoms (LUTS). These symptoms can include the inability to completely empty the bladder, urine retention, and a profound sensation of urgency. Direct Current (DC) ablation may be applied to treat these symptoms as a minimally-invasive alternative to surgery, medication, or thermal ablation, by causing tissue necrosis within the lateral lobes of the prostate. The objective of this study was to evaluate the effects of DC ablation in canine prostates by investigating how the resulting necrosis would change the macrostructure of the prostate for the potential treatment of symptomatic BPH. DC ablation is achieved by passing direct current through two electrodes in tissue, causing the formation of hydrogen ions at the anode and hydroxyl ions at the cathode. These ions diffuse through the tissue causing a pH of ∼1 at the anode, and ∼13 at the cathode. The extreme anti-physiological pH regions cause cellular necrosis and form in a predictable manner that is directly proportional to the charge delivered. The controlled shape and size of the lesions allow for predictable necrotic zones and enable treatment optimization. Treatment was performed on 6 acute and 8 chronic canine subject by performing a laparotomy and inserting electrodes through the prostate capsule. Acute subjects were sacrificed before recovery, while chronic subjects were sacrificed after 1, 3, 20, 40, and 60 days to investigate the healing cascade of the prostate after treatment. The chronic subjects were monitored for changes in urination or defecation patterns. Urine and blood samples were collected to evaluate the subjects' health throughout the study. Both macro-visual and pathological analyses were done to evaluate tissue response all acute and chronic subjects. Cellular necrosis within the prostate was significant and exhibited a dose response within the range of 0.07 to 0.10 cm3/coulomb for each electrode pair. The does response is defined as the ratio of necrotic tissue created, to charge delivered. Necrotic prostate cells resulted in voids with minimal scar tissue and a visible reduction in prostate mass. The treatment followed tissue planes constraining necrotic zones to the region between the prostate capsule and prostatic urethra. Both normal and hyperplastic tissues were treated and exhibited necrosis. No necrosis was observed outside the prostate. DC ablation has been demonstrated to create well-defined, predictable, and repeatable regions of cellular necrosis and structural changes in canine prostates. This technology may offer promise for the treatment of symptomatic BPH with an appropriately designed delivery system. Other potential applications include other benign and malignant tumors within the body.

Café culture. Interview by Carol Davis

Although every woman on health visitor Margaret Holtz's caseload was said to be breastfeeding on discharge from hospital, when she visited them some days later at home most had stopped. Determined to improve the situation, Ms Holtz set up a baby café.

Development of a DNA immunoadsorbent: coupling DNA on sepharose 4FF by an efficient activation method

To remove anti-DNA antibodies from a patient's plasma with systemic lupus erythematosus (SLE), a DNA immunoadsorbent was developed by covalently coupling calf thymus DNA on activated Sepharose 4FF. Sepharose 4FF was activated with 5-norbornene-2,3-dicarboximido carbonochloridate (Cl-CO-ONB), which was proven to be a very effective method for preparation of affinity chromatographic adsorbents. The activation was carried out in dry acetone using 4-(dimethylamine)pyridine (DMAP) and triethylamine (TEA) as catalysts at 4 degrees C or at room temperature. The coupling of DNA to the activated support was investigated as a function of pH, temperature, time, concentration of DNA, and activation level. It was found that the pH for optimal coupling is 3.0, and the amount of coupled DNA increases with an increase either in the concentration of DNA or the activation level. The maximum amount of coupled DNA could reach 1.0 mg DNA/ml support. The incubation of 5 to 20 ml of SLE plasma with 1.0 ml of adsorbent resulted in an 80 to 90% decline in the anti-DNA antibody level. Nonspecific adsorption for normal IgG and total protein is less than 15%.

Microcirculation of the fingernail fold in CAPD patients: preliminary observations

OBJECTIVE

To study changes in the peritoneal microcirculation during continuous ambulatory peritoneal dialysis (CAPD) by studying change in the microcirculation of the fingernails of CAPD patients.

SETTING

A university department.

DESIGN

A cross-sectional study of 10 nondiabetic patients on CAPD.

INTERVENTION

Hemorrheological tests of fingernail microcirculation using equipment built at our university.

MAIN OUTCOME MEASURES

Microcirculation was characterized by estimation of capillary density, red blood cell (RBC) column diameter, torque index, and RBC flow velocity semiquantitatively using videocapillaroscopy at the fingernail fold and plasma viscosimetry. Findings were correlated with treatment duration, peritoneal clearance, state of capillary morphology and hemodynamics, and lipid and fibrinogen levels.

RESULTS

Treatment duration was significantly correlated (p < or = 0.05) with low-density lipoprotein (LDL) (r = 0.776) and clearances of urea (r = -0.583), uric acid (r = -0.666), and potassium (r = -0.764). Changes in capillary morphology were correlated to clearances of urea (r = 0.643) and uric acid (r = 0.701). The fibrinogen concentration increases plasma viscosity (r = 0.799) and deteriorates the capillary state (r = -0.706). In addition, plasma viscosity correlates to cholesterol (r = 0.620, NS) and LDL (r = 0.781), but not to high-density lipoprotein and triglycerides.

CONCLUSION

CAPD treatment results in lipid abnormalities and high fibrinogen levels that may cause microvascular damage and poor perfusion. These interactions may explain the deterioration of peritoneal transport in some CAPD patients.

Primary or established liver cells for a hybrid liver? Comparison of metabolic features

It is currently in discussion whether or not established liver cell lines can be used for an extracorporeal liver assist device. Thus, metabolic features of primary hepatocytes, immortalized hepatocytes, and hepatoma cells were compared. The ability of these cells to process toxic blood of patients with hepatic failure was investigated by testing their viability in toxin enriched medium that was obtained by toxin separation from patients' blood via a molecular adsorbents recirculating system (MARS). In addition, glucose metabolism, urea synthesis, P450 dependent verapamil metabolism using high performance liquid chromatography, and interleukin-6 induced "acute phase" reaction by sulfodesoxysalicylic acid-polyacrylamide gel electrophoresis detected changes of albumin synthesis were determined in primary hepatocytes and in established liver cells. The viability of hepatoma cells after contact with the toxic compounds coming from the patients' blood was significantly decreased in comparison to that of immortalized hepatocytes and primary hepatocytes. Immortalized hepatocytes and hepatoma cells showed a significantly higher consumption of glucose associated with a significantly higher lactate synthesis. A basic urea synthesis rate could be measured in immortalized hepatocytes and hepatoma cells, but it was significantly lower than that of primary cells. P450 with its subenzyme CYP2C was inducible only in primary hepatocytes and in immortalized cells, but in the latter the enzymatic activity was lower than that of primary cells. The incubation with acute phase mediators resulted in a decrease of albumin synthesis in primary hepatocytes and in hepatoma cells, but it increased the albumin synthesis in immortalized hepatocytes. Summarizing these data, partially beneficial effects can be assumed if established cells are used in an extracorporeal liver assist device. These might include synthesis of some compounds and basic metabolic activities, such as urea synthesis. However, established liver cells showed clearly altered metabolic characteristics. The sufficient removal of toxic compounds requires additional strategies for detoxification by primary hepatocytes in sufficient amounts.

Measurements of plasma colloid osmotic pressure, total protein and sodium concentration during haemodialysis: can single-pool sodium modelling explain the results?

Considering the plasma colloid osmotic pressure (COP) as a possible parameter for the monitoring of dialysis treatment compatibility, a characteristic time course was found. The COP and the total protein concentration very often do not increase significantly during the first treatment hour in spite of ultrafiltration. An increase in the plasma sodium concentration, which was higher than expected, was found to be the reason for a plasma dilution effect. This can be explained by a transcapillary sodium transfer coefficient which is not infinitely high as assumed in single-pool sodium modelling. From a 2-pool model considering the plasma volume as a separate pool and including capillary filtration time courses for plasma sodium, total protein concentration and COP could be calculated, which was very similar to the measured curves.

[Determination of clearance for urea-controlled hemodialysis]

Through a simple variant of the urea model the qualitative influence of the dialyzer-clearance on the individual dialysis guidance is elucidated. Realization of the respective Kdtd/V-value require an exact knowledge of the in-vivo-urea-clearance of all available dialyzer types and their manipulation with the aid of blood flow. The theoretical connections are explained and possible parameters affecting the in-vivo-clearance are discussed. The results concerning the dependence of urea-clearance on the blood flow are presented in an urea-guided dialysis patient pool for all in the GDR customary in the trade or temporary available dialyzers. It is shown, that in MLW-dialyzers an influence on the urea-clearance about the blood flow is small because of their relatively thick-walled membrane. Therefore, the development of dialysis membranes with superior diffusible permeability is necessary.

Experiments with continuous hemofiltration and hemofiltrate regeneration in the rat

Experimental studies were made with continuous hemofiltration treatment for bilaterally nephrectomized rats and initial observations regarding the effects of such treatment on leukocyte and thrombocyte counts are reported. Hemofiltration of unanesthetized rats able to move freely within their cage could be continued for up to 30 h using a pump-driven ECC system. Blood parameters recorded during this treatment indicate that the detoxification was effective. In another series of experiments the water and electrolyte reabsorption capacity of the colon ascendens of healthy rats was tested by continuously supplying NaCl solution into the colon via a fistula. A large proportion, if not all, of the hemofiltrate can be discharged into the colon without diarrhoea. A final series of experiments showed that the three-stage operation (implantation of permanent catheters, connection of a permanent intestinal fistula and bilateral nephrectomy) is possible with the rat.

Shoulder forearm support for the subluxed shoulder

Subluxation of the shoulder is a common problem in patients who have had a stroke. Of the shoulder supports that are being used, many do not reduce the subluxation, and patients continue to complain of shoulder pain. The shoulder support designed for this study reduces subluxation, is custom fit, costs less, and is more comfortable than conventional slings. The sling is difficult to don but patients are able to perform self-ROM exercises without removing the sling. The sling consists of two parts: a shoulder support and forearm support. Both portions are worn when the patient is ambulating or standing. Only the shoulder support is worn when the patient is sitting with a lapboard. X-rays confirmed the reduction of subluxation, and patients reported decreased shoulder pain.

[Information content of endogenous creatinine parameters for kidney function diagnosis in glomerulonephropathies]

The functional-diagnostic findings, namely serum creatinine level, 24-h creatinine clearance, 1-h (morning) creatinine clearance and inulin clearance, of 58 glomerulo-nephropathy patients were evaluated using regression and correlation analysis. For clinical nephrology it is recommended not to measure 24-h creatinine clearance. For the purpose of diagnosing kidney function the information content of the serum creatinine level is sufficient if the hyperbolic relation to the GFR is taken into account. For clinical-scientific nephrology standardized short-term creatinine estimation in combination with direct or indirect GFR measurement (and other parameters of kidney function) is advisable.

[Experimental development of hollow cellulose membranes for blood detoxification]

In recent years there have been repeated demands in medical circles for new membranes for various purposes. At present attention is focussed on the development of membranes for the detoxification of blood. Using available technology and resources, it seemed appropriate to develop such hollow membranes out of cellulose by the viscose process. It is possible to give the membrane a suitable structure according to the use intended. The transport of matter and ultrafiltration can be influenced by varying the influence parameter in the spinning process via changes in the pore structure. In this way it is possible to produce hollow membranes for dialysis or ultrafiltration, with varying grades of permeability, out of cellulose by the viscose process.

[What is the current outlook for an implantable artificial kidney?]

Considering the homeostatic demands made by the organism on an artificial eliminating substitute kidney system, it seems that the haemofiltrative principle for transporting matter is the most suitable for simulating the natural glomerular kidney function in an implantable artificial kidney. Biophysical laws can be used to influence long-term filtrative efficiency and the blood-flow in the haemofilter system can be controlled by technical feedback regulation. Endogenically, the filtration process is, in terms of energy, driven by the aterial blood pressure (specifically, by the trans-membrane pressure thus generated). The definitive ultrafiltrate treatment takes place by intestinal reabsorption and elimination of the end products, whereby these functions may be assisted by the use of sorbents etc. or an adequate substitution therapy if reabsorption is insufficient. These processes can reasonably be triggered by neurohormonal feedback regulation if the homeostasis situation is greatly disturbed by the haemofiltration process. The implantable artificial kidney is thus a biochemical hybrid kidney.

Heparin binding and release properties of DEAE cellulose membranes

Two cellulose-based membranes, containing 5 and 20% N, N-diethyl-aminoethyl cellulose (DEAE) respectively, were investigated for ionic attachment of heparin and heparin release. Heparinization was achieved by recirculation of a heparin-containing glycine buffer over each membrane. Heparin was determined by chemical analysis or by 99mTc labelling. The heparin uptake was shown to be linearly dependent on the heparin content in the contacting fluid. Heparin release was studied by contacting heparinized membranes with saline, glycine buffer, phosphate buffer and plasma. Incubation with plasma brought about the release of 50% of the attached heparin. Crosslinking of the heparinized membrane with glutaraldehyde reduced the heparin release by one half. The release reaction is more critical in the case of increased heparin uptake and a more efficient immobilization of heparin appears necessary.

[Possibilities for using extracorporeal circulation in the rat]

An extracorporal system of freely mobile, unanaesthetized rats is presented. This model was used in experiments on the biocompatibility of silicone rubber and new types of hollow membranes. The results confirm a sensitive reaction of haematological parameters to various test substances, thus indicating that the model is very suitable. Carrying out a membrane plasma separation in rats makes it possible also to use rats for studies on detoxification and thus to use the advantages offered by this experimental animal to the full.

Selection of filters and evaluation in vitro of the selective dual filtration artificial kidney, SEDUFARK

Transport properties of different artificial kidney membranes have been studied employing substances with molecular weights ranging from 60 daltons (urea) to 62,000 daltons (dextran). The results from these studies were used to select filters for the SElective DUal Filtration ARtificial Kidney, SEDUFARK. Selection criteria for filters to be used in long-term clinical trials with SEDUFARK were based on biological tests showing toxicity of large molecular weight substances in uremic blood plasma and clinical advantages of returning middle molecular weight substances to the patient. The filters selected were used for evaluation in vitro of the complete SEDUFARK system. The results confirmed a theoretical analysis of this system, demonstrating that selective removal of substances within given molecular weight ranges from uremic blood plasma is feasible with a combination of commercial filters. The efficiency of the system, however, is limited due to the "cut-off" characteristics and hydraulic permeabilities of membrane types currently available.