Nocebo Effects on Muscular Performance - An Experimental Study About Clinical Situations.

Introduction: Nocebo effects are not only seen in studies of pharmacology and placebo/nocebo research but also in clinical everyday situations. For generation of objective and quantitative data on the impact of negative communication we have evaluated the immediate effects of common sentences, non-verbal signals and situations in the medical context on muscular performance. Methods: In an experimental study, 46 volunteers were tested by dynamometry of the deltoid muscle group to evaluate the maximal muscular strength during arm abduction. Baseline values were compared to performance after exposure to 18 verbal and non-verbal suggestions. Suggestions suspected to be negative were alternated with and compared to positively formulated alternatives. Results: Verbal and non-verbal communication produced significant effects on muscular performance, resulting mainly in weakening. The decrease in muscle strength after risk information for informed consent (91.4% of baseline) was absent, when benefits of the treatment were named coincidently. The weakening effect of asking about "pain" and "nausea" (89.4%), and of the announcement of medical interventions (91.7%) could be avoided with alternative wording. Impairment of muscular performance was also observed with the nocebo-inducers negative memory (89.5%) or uncertain future (93.3%), in contrast to a positive memory or the orientation into the presence. Non-verbal suggestions like overhead anesthesia induction (89.9%), a transport in strict flat supine position (89.1%), or a view from the window to a parking lot (94.1%) significantly reduced maximal muscle strength, whereas face-to face induction, half-sitting position and a view into the landscape did not. 8 out of 9 tested clinical situations reduced maximal arm muscle strength significantly, whereas alternative formulations did not. Conclusion: This study describes a quick, simple and uniform test using objective measurement of maximal muscle strength to allow for identification, quantification, and comparison of negative suggestions, regardless of their specific content and effect. Muscle strength is a clinically relevant parameter with regard to early mobilization, risk of falling and sufficient breathing. Furthermore, the observed impairment of muscular performance could reflect a general "weakening effect" of negative suggestions. In addition, the test facilitates development and verification of appropriate alternatives to prevent nocebo effects in patients, thereby improving patient communication.

Fat removal during cell salvage: an optimized program for a discontinuous autotransfusion device.

BACKGROUND: Fat in wound blood observed in orthopedic or cardiac surgery might pose a risk for fat embolism during blood salvage. Fat removal was optimized in the washing process. STUDY DESIGN AND METHODS: In an experimental study blood from fresh donations was adjusted to a hematocrit (Hct) of 25% and an admixture of 1.25% human tissue fat. This blood was processed with the cell salvage device XTRA in a modified program mode. Volumetric quantification of fat was performed after centrifugation of blood samples in Pasteur pipettes. From the volumes, the Hct levels and the concentrations of fat and other variables elimination rates and RBC recovery were calculated. RESULTS: Pretests showed wash volume, wash flow, and process interruptions affecting fat elimination. With the new optimized fat elimination program Pfat removal rate of fat increased to 98.5 ± 0.9% for the 225-mL bowl. The product had a mean Hct of 48.7 ± 1.2% and a RBC recovery rate of 93.5 ± 2.3%. The program conserved the high elimination rates for albumin, heparin, potassium, and free plasma hemoglobin (98.8, 99.3, 95.3, and 94.9%, respectively). Similar high fat removal was also observed with bowls of smaller size, namely, 98.1% for the 175-mL bowl and 98.2% for the 125- and the 55-mL bowls. With test blood of Hct 10% a mean fat elimination of 99.6 ± 01% was observed. CONCLUSIONS: A special program modification Pfat involving extra washing and RBC concentration steps significantly improves fat removal by the Latham bowl-based autotransfusion device XTRA, thus yielding results equivalent to the continuous cell salvage system.

Subsyndromal delirium after cardiac surgery.

OBJECTIVES: To evaluate the incidence of subsyndromal delirium (SSD) after cardiac surgery and its impact on clinical outcome. DESIGN: In this prospective study, 506 patients were screened for SSD and clinical delirium (CD) using the Intensive Care Delirium Screening Checklist. RESULTS: 150 (34%) patients were classified as having SSD and 54 (12%) patients as having CD. 2% of SSD patients developed CD. Patients' age, EuroSCORE, postoperative the Acute Physiology and Chronic Health Evaluation II, the incidences of emergency operations, and the number of aortic surgery increased from non-delirious (ND) to SSD. Intensive care unit (ICU) and hospital stays were longer in CD compared with SSD patients. ND patients did not differ from SSD patients regarding duration of ventilation, ICU stay, or hospital stay. The rate of home discharge decreased from ND over SSD to CD patients. Mortality in SSD patients did not differ from ND or CD patients. CONCLUSION: SSD showed a prevalence of 34% in patients after cardiac surgery. SSD occurred independent of CD for the majority of patients. Except for a lower rate of home discharge, the clinical outcome did not differ from that of ND patients. According to our data, SSD does not represent a preliminary or resolving stage of delirium.

Fat removal during cell salvage: a comparison of four different cell salvage devices.

BACKGROUND: Fat embolism is a possible risk factor for pulmonic and cerebral dysfunction after orthopedic and heart surgery. It is unknown whether fat occasionally observed during cell salvage adds to the risk of fat embolism after retransfusion. We have examined the fat removal capacities of different cell salvage devices including discontinuous and a continuous system under various conditions. STUDY DESIGN AND METHODS: In an experimental study ABO-matched banked blood was adjusted to a hematocrit of 20%, and 1.25% of human fat was added. This blood was processed with the cell salvage devices XTRA and Electa, CATS, or Cell Saver 5 plus. Fat in the blood samples was quantified by volumetric measurement after centrifugation in Pasteur pipettes and by gravimetric measurement after extraction of fat in organic solvents and phase partition. Performance in fat removal was tested with different programs, bowl sizes, and additional filtration. RESULTS: The continuous system consistently showed a high fat removal rate of 99.8 ± 0.2%. Fat accumulated in the wash disposal, but not in the product. In the Latham bowl-based discontinuous systems, fat removal varied from 69.2 to 92.8 ± 4.4% depending on the program mode, but not on the bowl size. Additional filtration increased fat removal to 96.7 ± 2.2%, but also increased red blood cell loss. CONCLUSIONS: Fat contamination of wound blood can be detected by volumetric and gravimetric measurements. Continuous salvage systems remove fat to a higher extent than discontinuous systems. The fat removal capacities of discontinuous systems depend on the program mode and can be improved by filtration.

Local anesthetic cytotoxicity on human mesenchymal stem cells during chondrogenic differentiation.

PURPOSE: This study was to investigate the cytotoxic potency of local anesthetics on human mesenchymal stem cells during chondrogenesis. METHODS: Aggregates were created from density-gradient centrifugation-separated bone marrow-derived mesenchymal stem cells. After 7, 14, and 21 days, aggregates were analyzed histologically and immunohistochemically and exposed to equipotent concentrations of bupivacaine, ropivacaine, and mepivacaine for 1 h. Cell viability, apoptosis, and necrosis were determined using live-dead and caspase staining. Additionally, following a 1-h exposure on day 7, aggregates were cultured under chondrogenic conditions until day 21 to assess the effects of local anesthetics on differentiation potency of mesenchymal stem cells. RESULTS: In the course of chondrogenesis, mesenchymal stem cells were embedded in varying amount and structure of cartilage-specific extracellular matrix. Contents of sulfated glycosaminoglycan, type I and II collagen increased from day 7 to day 21. Compared to control, death rates of mesenchymal stem cells were significantly elevated 1 day after treatment at 7 and 14 days. Four days after exposure, death rates were 13-15 % at 7 and 11-17 % at 14 days. Mesenchymal stem cell viability in aggregates at 21 days was unchanged to controls. The width of the superficial aggregate zone containing stem cell necrosis decreased with elongated differentiation time. Apoptosis rates were elevated in the edge regions of aggregates, reaching maximum values 4 days after treatment. Local anesthetic exposure on day 7 reduced Collagen II, but not DNA contents in aggregates at 21 days. Bupivacaine, ropivacaine, and mepivacaine did not differ in mesenchymal stem cell cytotoxicity in aggregates. CONCLUSION: Local anesthetic exposure results in cytotoxicity of mesenchymal stem cells undergoing chondrogenesis, especially in superficial layers. Therefore, induced cell damage should be avoided during chondrogenesis of mesenchymal stem cells, particularly early after cartilage repair.

Processing of small volumes in blood salvage devices.

BACKGROUND: New technical developments such as a small Latham bowl, a continuous autotransfusion system, and a dynamic disk designed for postoperative autotransfusion raise hopes for a possible application of blood salvage in young children. However, the minimal blood volume for effective processing under clinically relevant conditions has yet to be determined. STUDY DESIGN AND METHODS: Fresh blood from volunteer donations adjusted to a hematocrit (Hct) of 10% was used to test ELECTA (Sorin) equipped with a 55-mL bowl, C.A.T.S (Fresenius) in the pediatric program mode, and OrthoPAT (Haemonetics). Twenty-milliliter portions of red blood cells (RBCs) were added and processed under various conditions, including clinically relevant first filling and intermittent emptying. RBC recovery and availability and plasma elimination were calculated from the Hct, free hemoglobin, and total protein. RESULTS: The main impediment to recovery and availability was the first filling. There, RBC recovery was significantly reduced, while it subsequently varied between 93 and 98%. To produce the first 30 mL of RBCs, ELECTA required 42 mL and C.A.T.S and OrthoPAT 62 mL owing to the dead space of the separation chamber or reservoir, respectively. RBC availability was much higher in subsequent processes, with only minimal differences between the three devices. They all consistently provided high plasma elimination rates. CONCLUSION: The continuous system showed no advantage over a small Latham bowl. From the results it can be calculated that the limit for feasible cell salvage at present is an infant of 6 months. All three devices are suitable for the processing of small volumes, but have the scope for further optimization.

Cytotoxicity of local anesthetics on human mesenchymal stem cells in vitro.

PURPOSE: The purpose of this study was to investigate the cytotoxic potency of local anesthetics on human mesenchymal stem cells (MSCs) before and after chondrogenic differentiation. METHODS: MSCs were exposed to equal and equipotent concentrations of bupivacaine, ropivacaine, and mepivacaine for 1 hour. Cell viability, apoptosis, and necrosis were determined using flow cytometry and live/dead staining. After chondrogenic differentiation, MSC viability was determined in aggregates exposed to equipotent concentrations of the named agents, applying fluorescence microscopy. RESULTS: All local anesthetics showed detrimental cytotoxic effects on MSC monolayer cultures in a concentration- and time-specific manner. Minimum viability rates were found 96 hours after a 1-hour exposure. Bupivacaine 0.5% caused a reduction of vital MSCs to 5% ± 1%. Sixteen percent ± 2% viable cells were detected after treatment with 0.75% ropivacaine. Exposure to 2% mepivacaine decreased vitality rates to 1% ± 0%. Ropivacaine was significantly less cytotoxic than were bupivacaine and mepivacaine. Immediate cell death was mainly caused by necrosis followed by apoptosis afterward. Viability rates of MSCs embedded in cartilaginous tissue after chondrogenic differentiation were not reduced by local anesthetic treatment. CONCLUSIONS: Local anesthetics are cytotoxic to MSCs in a concentration-, time-, and agent-dependent manner in monolayer cultures but not in whole-tissue probes. CLINICAL RELEVANCE: MSCs are applied for treatment of cartilage defects. Intra-articular application of local anesthesia is a common procedure in pain management and has shown chondrotoxic effects. Therefore, it is crucial to evaluate the impact of local anesthetics on human MSCs and regenerative cartilage tissue engineering.

The cytotoxicity of bupivacaine, ropivacaine, and mepivacaine on human chondrocytes and cartilage.

BACKGROUND: Intraarticular injections of local anesthetics are frequently used as part of multimodal pain regimens. However, recent data suggest that local anesthetics affect chondrocyte viability. In this study, we assessed the chondrotoxic effects of mepivacaine, ropivacaine, and bupivacaine. We hypothesized that specific cytotoxic potencies directly correlate with analgesic potencies, and that cytotoxic effects in intact cartilage are different than in osteoarthritic tissue. METHODS: Human articular chondrocytes were exposed to equal and equipotent concentrations of bupivacaine, ropivacaine, and mepivacaine for 1 hour. Cell viability, apoptosis, and necrosis were determined at predefined time points using flow cytometry, live-dead staining, and caspase detection. Intact and osteoarthritic human cartilage explants were treated with equipotent concentrations of named drugs to determine cell viability applying fluorescence microscopy. RESULTS: Chondrotoxic effects increased from ropivacaine to mepivacaine to bupivacaine in a time-dependent and concentration-dependent manner. Compared with control, bupivacaine 0.5% decreased chondrocyte viability to 78% ± 9% (P = 0.0183) 1 hour and 16% ± 10% (P < 0.0001) 24 hours later, as determined by live-dead staining in monolayer cultures. Viability rates were reduced to 80% ± 7% (P = 0.0475) 1 hour and 80% ± 10% (P = 0.0095) 24 hours after treatment with ropivacaine 0.75%. After exposure to mepivacaine 2%, viable cells were scored 36% ± 6% (P < 0.0001) after 1 hour and 30% ± 11% (P < 0.0001) after 24 hours. Ropivacaine treatment was less chondrotoxic than bupivacaine (P = 0.0006) and mepivacaine exposure (P = 0.0059). Exposure to concentrations up to 0.25% of bupivacaine, 0.5% of ropivacaine, and 0.5% of mepivacaine did not reveal significant chondrotoxicity in flow cytometry. However, chondrotoxicity did not correlate with potency of local anesthetics. Immediate cell death was mainly due to necrosis followed by apoptosis. Cellular death rates were clearly higher in osteoarthritic compared with intact cartilage after bupivacaine, mepivacaine, and ropivacaine treatment in a decreasing order. CONCLUSION: Bupivacaine, ropivacaine, and mepivacaine are chondrotoxic in a time-dependent, concentration-dependent, and drug-dependent manner. Chondrotoxic and analgesic potencies do not directly correlate. Cellular death rates were higher in osteoarthritic compared with intact cartilage after local anesthetic treatment.

Washing of banked blood by three different blood salvage devices.

BACKGROUND: Storage lesions in red blood cells (RBCs) lead to an accumulation of soluble contaminants that can compromise the patient. Organ failures, coagulopathies, and cardiovascular events including lethal cardiac arrest have been reported, especially with massive transfusion or in pediatric patients. Washing improves the quality of stored RBCs, and autotransfusion devices have been proposed for intraoperative processing, but these devices were designed for diluted wound blood, and limited data on their performance with RBCs are available. STUDY DESIGN AND METHODS: Three autotransfusion devices (Electa, Sorin; CATS, Fresenius; OrthoPAT, Haemonetics) differing in function of their centrifugation chambers were evaluated with RBCs at the end of their shelf life and with dilutions thereof. Elimination rates of potassium, plasma free hemoglobin, total protein, citrate, acid equivalents, and iomeprol added as a marker substance were analyzed, in addition to RBC recoveries. RESULTS: Product hematocrit (Hct) levels ranged between 54.8 and 72.6%. RBC recovery rates were between 62.7 and 95.0%, the lowest being with the OrthoPAT processing of undiluted RBCs. Plasma elimination rates increased with predilution and ranged from 46.6% to 99.5%, the lowest being with the CATS and undiluted RBCs. Washing did not change pH and buffering capacity of RBCs. CONCLUSION: Autotransfusion devices offer a practical and obviously economical option to wash banked RBCs intraoperatively to prevent hyperkalemia and other disturbances in massive transfusion or pediatric patients. Predilution improves elimination rates, especially in devices that produce high product Hct levels. With a Y-tubing the RBCs should bypass reservoir and vacuum, and the procedure should be guarded by a policy and procedure manual and a quality management system.

Estrogen reduces cellular aging in human mesenchymal stem cells and chondrocytes.

Chondrocyte aging is associated with cartilage degeneration and senescence impairs the regenerative potential of mesenchymal stem cells (MSCs). Estrogen exerts profound effects on human physiology including articular cartilage and MSCs. The present study should analyze the effects of pre- and postmenopausal estrogen concentrations on chondrogenic cells. Physiologic premenopausal concentrations of 17ß-estradiol (E(2)) significantly decelerated telomere attrition in MSCs and chondrocytes while postmenopausal E(2) concentration had no significant effects. The estrogen agonist-antagonist tamoxifen did not affect telomere biology, but inhibited the E(2) -stimulated reduction in telomere shortening. E(2) and tamoxifen did not influence cell proliferation, cell morphology, and ß-galactosidase staining in chondrogenic cells. E(2) treatment did not affect the telomere-associated proteins TRF1 and TRF2. E(2) had no regulatory effects on the expression rates of the cell cycle regulator p21 and the DNA repair proteins SIRT1 and XRCC5. In spite of reducing telomere shortening in aging MSCs and chondrocytes, estrogen is not able to prevent somatic cells from replicative exhaustion and from finally entering senescence. The fade of telomere shortening under pre- to postmenopausal estrogen concentrations suggests, at least in part, a senescence-dependent cause for the onset of osteoarthritis in women after menopause.