The Effects of S(???)-, R(+)-, and Racemic Bupivacaine on Lysophosphatidate-Induced Priming of Human Neutrophils

The Effect of Local Anesthetics on Neutrophils in the Context of Different Isolation Techniques

Various functions of polymorphonuclear neutrophils (PMNs) are related to diseases and postoperative plasma changes. The influence of some local anesthetics (LAs) on PMNs obtained by conventional isolation methods and their functions has already been demonstrated. This study investigates the effect of selected LAs on PMNs, comparing a new isolation method with conventional ones. To obtain the PMNs, we performed either gelafundin sedimentation, hypotonic lysis or density gradient centrifugation. Subsequently, PMNs were mixed with different concentrations of bupivacaine, levobupivacaine, lidocaine or ropivacaine. Live cell imaging and flow cytometry were performed to quantify the migration, ROS production, NETosis and antigen expression of PMNs. We found the inhibition of chemotaxis and ROS production by LAs. PMNs showed a strong reduction in time to half maximal NETosis in response to bupivacaine and lidocaine, but not to levobupivacaine and ropivacaine. We also found distinct differences in survival time and migration duration between the isolation methods. This suggests that the careful selection of LAs has a short-term impact on in vitro PMNs.

Impact of Local Anesthetics on Cancer Behavior and Outcome during the Perioperative Period: A Review

There is a growing interest regarding the impact of the perioperative period and the application of anesthetic drugs on the recurrence of cancer metastases. Among them, the use of amide-type local anesthetics seems promising since in vitro studies and animal models have shown their potential to inhibit the Intercellular Adhesion Molecule 1 (ICAM-1) expression and Src activity, which are clearly implicated in the process of inflammation and cancer metastases. This review emphasizes the potential of amide-type local anesthetics in this context.

Mechanisms of action of fascial plane blocks: a narrative review

BACKGROUND

Fascial plane blocks (FPBs) target the space between two fasciae, rather than discrete peripheral nerves. Despite their popularity, their mechanisms of action remain controversial, particularly for erector spinae plane and quadratus lumborum blocks.

OBJECTIVES

This narrative review describes the scientific evidence underpinning proposed mechanisms of action, highlights existing knowledge gaps, and discusses implications for clinical practice and research.

FINDINGS

There are currently two plausible mechanisms of analgesia. The first is a local effect on nociceptors and neurons within the plane itself or within adjacent muscle and tissue compartments. Dispersion of local anesthetic occurs through bulk flow and diffusion, and the resulting conduction block is dictated by the mass of local anesthetic reaching these targets. The extent of spread, analgesia, and cutaneous sensory loss is variable and imperfectly correlated. Explanations include anatomical variation, factors governing fluid dispersion, and local anesthetic pharmacodynamics. The second is vascular absorption of local anesthetic and a systemic analgesic effect at distant sites. Direct evidence is presently lacking but preliminary data indicate that FPBs can produce transient elevations in plasma concentrations similar to intravenous lidocaine infusion. The relative contributions of these local and systemic effects remain uncertain.

CONCLUSION

Our current understanding of FPB mechanisms supports their demonstrated analgesic efficacy, but also highlights the unpredictability and variability that result from myriad factors at play. Potential strategies to improve efficacy include accurate deposition close to targets of interest, injections of sufficient volume to encourage physical spread by bulk flow, and manipulation of concentration to promote diffusion.

Effect of Lignocaine Concentration on Human Fibroblasts Growth in Eyes Undergoing Trabeculectomy: An in vitro Study

Purpose

To evaluate the effect of lignocaine on growth and apoptosis indication of primary human Tenon's capsule fibroblast (HTFs) in an in vitro model.

Patients and Methods

Tenon's capsule tissue obtained from patients undergoing trabeculectomy were grown in cell culture medium. The effect of different concentrations of lignocaine (0.5, 1.0, 1.5, and 2%) on the morphology and growth of the fibroblasts was studied using microscopy, cell viability, and proliferation assay, and apoptosis was detected using the FITC Annexin V Apoptosis Kit.

Results

Morphological changes similar to those of apoptotic cells, including cytoplasmic vacuolation, shrinkage, and rounding were visualized in the cells treated with concentrations greater than 1.0% (i.e., 1.5, 2.0%). Though proliferation inhibition was found with all four concentrations (0.5–2.0%), the viability of cells decreased from 1.0% lignocaine.

Conclusion

0.5% lignocaine prevents proliferation of fibroblasts without causing apoptosis in vitro.

A prospective, randomized, blinded study of continuous ropivacaine infusion in the median sternotomy incision following cardiac surgery

OBJECTIVE

The aim of this prospective, randomized, double-blind, placebo controlled trial was to evaluate the safety and efficacy of continuous ropivacaine infusion of into the sternal wound.

METHODS

We planned to enroll 200 patients scheduled for various cardiac surgical procedures into the study. Patients, in a double-blind randomized fashion, were given either normal saline or 0.3% ropivacaine through 2 subcutaneous multiport catheters placed on either side of the sternal split at an infusion rate of 4 mL/h for 64 hours. The efficacy outcomes measured were time to extubation of the trachea, intensive care unit and hospital stay duration, pain scores, and narcotic usage. The safety outcomes measured were systemic local anesthetic toxicity, major cardiac complications, and wound infection.

MEASUREMENTS AND MAIN RESULTS

The data safety monitoring board stopped the study after enrolling 85 patients because of excessive sternal wound infections (9%, n = 44) in the ropivacaine group. This rate of infection was not statistically different from the control group (0%, n = 41, P = 0.12), but it was statistically different from our historical incidence of sternal wound infection (1.9%, no = 6381, P = 0.002). There was also a lack of evidence of efficacy for time to extubation of the trachea, narcotic usage, and pain control.

CONCLUSIONS

The phase III trial did not show improvement in time to extubation of the trachea or pain control in the 0.3% ropivacaine group, but it was stopped early by the data safety monitoring board.

Lidocaine inhibits NIH-3T3 cell multiplication by increasing the expression of cyclin-dependent kinase inhibitor 1A (p21)

BACKGROUND

We explored molecular mechanisms by which lidocaine inhibits growth in the murine embryonic fibroblast cell line NIH-3T3. Local anesthetics can adversely affect cell growth in vitro. Their effects on wound healing are controversial. We examined the effects and novel mechanisms by which lidocaine affects in vitro multiplication of the murine fibroblast cell line NIH-3T3.

METHODS

NIH-3T3 cells were grown in culture with lidocaine [0, 0.05, 0.5, 1, 2, and 5 mM]. Cell multiplication was assessed by determining cell counts on subsequent days, while mechanisms by which inhibition occurred were evaluated by bromodeoxyuridine uptake, gene expression using polymerase chain reaction array, and Western blot analysis to verify increased levels of affected proteins.

RESULTS

Lidocaine caused dose-dependent inhibition of multiplication of NIH-3T3 cells. Effects ranged from no inhibition [0.05 and 0.5 mM] and mild inhibition [1 mM], to severe inhibition [2 and 5 mM] [P = 0.006]. Lidocaine 2 mM inhibited bromodeoxyuridine uptake at day 3.5 [P = 0.02 versus control, and P = 0.0495 vs 1 mM lidocaine]. On day 1.5, lidocaine upregulated expression of cyclin-D1 and cyclin-dependent kinase inhibitor 1A [p21]. On day 2.5, lidocaine increased the levels of p21 protein.

CONCLUSIONS

Low concentrations of lidocaine, as would be seen in plasma after spinal, epidural, or plexus anesthesia, do not significantly affect multiplication of fibroblasts. Higher doses of lidocaine arrest cell multiplication at the S-phase of the growth cycle by upregulation of p21, an extremely potent inhibitor of cell multiplication. Higher concentrations, as would be seen after tissue infiltration, severely inhibit fibroblast multiplication and thus may impair wound healing.

Young patients with shoulder chondrolysis following arthroscopic shoulder surgery treated with total shoulder arthroplasty

Chondrolysis following shoulder arthroscopy is a devastating complication, often seen in young patients. After nonoperative measures have been exhausted, there are few treatment options available that reliably improve pain and function. The purpose of this study is to examine the intra-operative findings, radiographic features, and clinical outcomes of a series of patients with chondrolysis following arthroscopic surgery managed with a total shoulder arthroplasty. A retrospective review was performed on 11 patients (average age 39) with shoulder chondrolysis following arthroscopy. Attention was focused on review of the index arthroscopy, radiographs, and functional outcome scores prior to total shoulder arthroplasty, as well as intra-operative cultures, histology, radiographs, and functional outcomes from most recent follow-up. All patients were treated with total shoulder arthroplasty at an average of 26 months after the index arthroscopy. Preoperative and postoperative radiographs were reviewed, and outcomes were compared using validated measurements. Statistically significant improvements in shoulder abduction (89 degrees -123 degrees , P = .027), external rotation (26 degrees -48 degrees , P = .037), total ASES scores (30-77.5, P = .0039), and SST scores (3-8, P = .0078) were noted. Ten patients subjectively rated their outcomes as good or excellent, with 1 as satisfactory. Chondrolysis after shoulder arthroscopy has a rapid clinical progression and is likely multifactorial in etiology. Early results of total shoulder arthroplasty show an opportunity for improvements in pain and function; however, progressive glenoid radiolucencies may develop in these patients.