Modification of Bupivacaine-Induced Myotoxicity with Dantrolene and Caffeine In Vitro.

BACKGROUND: Local anesthetics, especially bupivacaine, have myotoxic effects in clinically used concentrations and context. Detailed mechanisms of these effects are unknown, but an increase in intracellular calcium levels is suspected to be the most important trigger. Dantrolene and caffeine modify cellular calcium release from the sarcoplasmic reticulum. The aim of our study was to investigate the effect of dantrolene and caffeine on bupivacaine-induced myotoxicity in vitro. METHODS: A cell culture model of primary muscle cells of BALB/c AnNCrl mice was established. Cells were incubated simultaneously with increasing concentrations of bupivacaine, dantrolene, and caffeine. The fraction of dead cells was calculated after staining with propidium iodide and analysis by flow cytometry. The half-maximal inhibitory concentration of bupivacaine was calculated for each concentration. Group differences were determined by using 1-way analysis of variances with subsequent post hoc 1-way Dunnett t test. RESULTS: Both dantrolene and caffeine alone had no effect on muscle cell survival. Increasing concentrations of bupivacaine caused increasing cell death. Dantrolene dose-dependently reduced the fraction of necrotic cells, whereas caffeine dose-dependently increased the fraction of dead cells. CONCLUSIONS: Dantrolene attenuated, and caffeine enhanced, bupivacaine-induced myotoxicity, presumably by modifying sarcoplasmic calcium release. This indicates that intracellular calcium release is an important factor for local anesthetic-induced cell death.

The myotoxic effect of bupivacaine and ropivacaine on myotubes in primary mouse cell culture and an immortalized cell line.

BACKGROUND: The 2 local anesthetics (LAs) bupivacaine and ropivacaine have acute cytotoxic effects on different tissues. In this respect, LA-induced myotoxicity has been subject to various studies; however, the exact mechanisms are still not fully understood. Most in vitro studies use immortalized cell lines because of feasibility. Thus, establishing a primary cell line might result in more accurate results. In this study, we examined the effects of immortalization on bupivacaine- and ropivacaine-induced myotoxicity in vitro. METHODS: An immortalized (N = 6) and a primary cell line (N = 8) of the same tissue and species were established, and differentiation in myotubes was induced. Cells were exposed to increasing concentrations of bupivacaine and ropivacaine for 1 or 2 hours, respectively. Twenty-four and 48 hours after treatment, the fractions of dead and vital cells were measured using flow cytometry. Significance was tested through 1-way analysis of variance with post hoc Dunnett T3 test. Medians of dataset pairs were compared by T test. RESULTS: In both cell lines, increasing concentrations of both LAs resulted in decreased cell survival (e.g., P < 0.001 for 5000 ppm bupivacaine, 1 or 2 hours of incubation, and 24 hours recovery in both cell lines). For the same LA concentrations, survival was significantly higher in the immortalized cell culture (e.g., P < 0.001 for 2500 ppm ropivacaine, 1 hour of incubation, and 24 hours recovery). In addition, equal concentrations of bupivacaine resulted in significantly fewer vital cells compared with ropivacaine (e.g., P = 0.032 for 2500 ppm ropivacaine, 1 hour of incubation, and 24 hours recovery). Two hours of incubation resulted in a significantly higher rate of dead cells compared with 1 hour of incubation (e.g., P = 0.004 for C2C12 cells, 2500 ppm bupivacaine, and 24 hours recovery). CONCLUSIONS: Primary skeletal muscle cells are more vulnerable to LAs than immortalized cells. The higher myotoxic potential of bupivacaine compared with ropivacaine in vivo can be reproduced in vitro. Incubation time has an influence on cell survival.

Voice function and voice-related quality of life in the elderly.

BACKGROUND: Many studies have referred to the effects of age on voice and the consequences of these changes. However, only little is known about the adverse effects of voice changes on quality of life in the elderly. OBJECTIVE: This study focuses on self-perception of voice in seniors as assessed by the Voice-Related Quality of Life (V-RQOL) questionnaire, on voice quality as measured by the Dysphonia Severity Index (DSI) and on the correlation between these parameters. METHODS: V-RQOL and DSI were measured as previously described in 107 non-treatment-seeking test persons without voice complaints (76 women and 31 men; mean age 78.7 ± 6.8 years, range 66-94 years). RESULTS: The mean V-RQOL value was 94.4 ± 9.8%. The mean value of the DSI in all participants was 1.2 ± 2.4. There was no significant correlation between the V-RQOL and DSI, either in women (p = 0.11), men (p = 0.58) or the whole study group (p = 0.26). CONCLUSION: Both the V-RQOL questionnaire and the DSI may be applied to seniors. As self-perception of voice and voice function do not correlate, both parameters have to be measured for voice assessment.

[A comparison of various supraglottic airway devices for fiberoptical guided tracheal intubation]. / Uma comparação de vários dispositivos supraglóticos para intubação traqueal guiada por fibra óptica.

BACKGROUND: Fiberoptical assisted intubation via placed supraglottic airway devices has been described as safe and easy procedure to manage difficult airways. However visualization of the glottis aperture is essential for fiberoptical assisted intubation. Various different supraglottic airway devices are commercially available and might offer different conditions for fiberoptical assisted intubation. The aim of this study was to compare the best obtainable view of the glottic aperture using different supraglottic airway devices. METHODS: With approval of the local ethics committee 52 adult patients undergoing elective anesthesia were randomly assigned to a supraglottic airway device (Laryngeal Tube, Laryngeal Mask Airway I-Gel, Laryngeal Mask Airway Unique, Laryngeal Mask Airway Supreme, Laryngeal Mask Airway Aura-once). After standardized induction of anaesthesia the supraglottic airway device was placed according to the manufacturers recommendations. After successful ventilation the position of the supraglottic airway device in regard to the glottic opening was examined with a flexible fiberscope. A fully or partially visible glottic aperture was considered as suitable for fiberoptical assisted intubation. Suitability for fiberoptical assisted intubation was compared between the groups (H-test, U-test; p<0.05). RESULTS: Demographic data was not different between the groups. Placement of the supraglottic airway device and adequate ventilation was successful in all attempts. Glottic view suitable for fiberoptical assisted intubation differed between the devices ranging from 40% for the laringeal tube (LT), 66% for the laryngeal mask airway Supreme, 70% for the Laryngeal Mask Airway I-Gel and 90% for both the Laryngeal Mask Airway Unique and the Laryngeal Mask Airway Aura-once. CONCLUSION: None of the used supraglottic airway devices offered a full or partial glottic view in all cases. However the Laryngeal Mask Airway Unique and the Laryngeal Mask Airway Aura-once seem to be more suitable for fiberoptical assisted intubation compared to other devices.

A comparison of various supraglottic airway devices for fiberoptical guided tracheal intubation.

BACKGROUND: Fiberoptical assisted intubation via placed supraglottic airway devices has been described as safe and easy procedure to manage difficult airways. However visualization of the glottis aperture is essential for fiberoptical assisted intubation. Various different supraglottic airway devices are commercially available and might offer different conditions for fiberoptical assisted intubation. The aim of this study was to compare the best obtainable view of the glottic aperture using different supraglottic airway devices. METHODS: With approval of the local ethics committee 52 adult patients undergoing elective anesthesia were randomly assigned to a supraglottic airway device (Laryngeal Tube, Laryngeal Mask Airway I-Gel, Laryngeal Mask Airway Unique, Laryngeal Mask Airway Supreme, Laryngeal Mask Airway Aura-once). After standardized induction of anesthesia the supraglottic airway device was placed according to the manufacturers recommendations. After successful ventilation the position of the supraglottic airway device in regard to the glottic opening was examined with a flexible fiberscope. A fully or partially visible glottic aperture was considered as suitable for fiberoptical assisted intubation. Suitability for fiberoptical assisted intubation was compared between the groups (H-test, U-test; p<0.05). RESULTS: Demographic data was not different between the groups. Placement of the supraglottic airway device and adequate ventilation was successful in all attempts. Glottic view suitable for fiberoptical assisted intubation differed between the devices ranging from 40% for the laringeal tube (LT), 66% for the laryngeal mask airway Supreme, 70% for the Laryngeal Mask Airway I-Gel and 90% for both the Laryngeal Mask Airway Unique and the Laryngeal Mask Airway Aura-once. CONCLUSION: None of the used supraglottic airway devices offered a full or partial glottic view in all cases. However the Laryngeal Mask Airway Unique and the Laryngeal Mask Airway Aura-once seem to be more suitable for fiberoptical assisted intubation compared to other devices.

A comparison of fiberoptical guided tracheal intubation via laryngeal mask and laryngeal tube.

BACKGROUND: Fiberoptical assisted intubation via a placed laryngeal mask airway (LMA) has been described as save and easy procedure to manage a difficult airway. The laryngeal tube (LT) is a promising alternative to the LMA as supraglottic airway device. Fiberoptical assisted intubation via LT is possible, however considered more difficult. The aim of this study was to compare the fiberoptical assisted intubation via LT and LMA. MATERIALS AND METHODS: A total of 22 anesthesiologists with different levels of experience participated in the study performed on an adult airway model. Primarily the supraglottic device was placed and correct position was confirmed by successful ventilation. A 5 mm internal diameter tracheal tube was loaded onto a flexible 3.6 mm fiberscope and the so prepared device was inserted into the proximal lumen of the LMA or the LT. The glottis was passed under visual control and the tube advanced into the trachea. After removal of the fiberscope, ventilation was examined clinically by inspection. Success rates, procedure time and observed complications of LMA versus LT were compared (U-test; P < 0.05). RESULTS: Placement of the endotracheal tube was successful in all attempts using both the LMA and LT. There was no difference in the time needed for the placement procedure (33 [26-38] s LMA; 35 [32-38] s LT). Only minor technical complications were observed in both groups. CONCLUSION: A fiberoptical assisted intubation via LT can be considered as a relevant alternative in advanced airway management.

A comparison of various supraglottic airway devices for fiberoptical guided tracheal intubation / Uma comparação de vários dispositivos supraglóticos para intubação traqueal guiada por fibra óptica

Abstract Background: Fiberoptical assisted intubation via placed supraglottic airway devices has been described as safe and easy procedure to manage difficult airways. However visualization of the glottis aperture is essential for fiberoptical assisted intubation. Various different supraglottic airway devices are commercially available and might offer different conditions for fiberoptical assisted intubation. The aim of this study was to compare the best obtainable view of the glottic aperture using different supraglottic airway devices. Methods: With approval of the local ethics committee 52 adult patients undergoing elective anesthesia were randomly assigned to a supraglottic airway device (Laryngeal Tube, Laryngeal Mask Airway I-Gel, Laryngeal Mask Airway Unique, Laryngeal Mask Airway Supreme, Laryngeal Mask Airway Aura-once). After standardized induction of anesthesia the supraglottic airway device was placed according to the manufacturers recommendations. After successful ventilation the position of the supraglottic airway device in regard to the glottic opening was examined with a flexible fiberscope. A fully or partially visible glottic aperture was considered as suitable for fiberoptical assisted intubation. Suitability for fiberoptical assisted intubation was compared between the groups (H-test, U-test; p < 0.05). Results: Demographic data was not different between the groups. Placement of the supraglottic airway device and adequate ventilation was successful in all attempts. Glottic view suitable for fiberoptical assisted intubation differed between the devices ranging from 40% for the laringeal tube (LT), 66% for the laryngeal mask airway Supreme, 70% for the Laryngeal Mask Airway I-Gel and 90% for both the Laryngeal Mask Airway Unique and the Laryngeal Mask Airway Aura-once. Conclusion: None of the used supraglottic airway devices offered a full or partial glottic view in all cases. However the Laryngeal Mask Airway Unique and the Laryngeal Mask Airway Aura-once seem to be more suitable for fiberoptical assisted intubation compared to other devices.

Resumo Justificativa: A intubação guiada por fibra óptica (IGFO) através de dispositivo supraglótico (DSG) tem sido descrita como um procedimento seguro e fácil para o manejo de via aérea difícil. No entanto, a visibilização da abertura da glote é essencial para a IGFO. Vários DSGs diferentes estão comercialmente disponíveis e podem oferecer diferentes condições para a IGFO. O objetivo deste estudo foi comparar a melhor visão obtida da abertura da glote com o uso de diferentes DSGs. Métodos: Com a aprovação do Comitê de Ética local, 52 pacientes adultos submetidos à anestesia eletiva foram randomicamente designados para um dos DSGs: tubo laríngeo (TL), máscara laríngea (ML) I-Gel, ML Unique, ML Supreme, ML AuraOnce. Após a indução padronizada da anestesia, o DSG foi colocado de acordo com as recomendações do fabricante. Após ventilação bem-sucedida, a posição do DSG em relação à abertura da glote foi examinada com um endoscópio flexível. Uma abertura da glote total ou parcialmente visível foi considerada como adequada para a IGFO. A adequação para a IGFO foi comparada entre os grupos (teste-H, teste-U; p < 0,05). Resultados: Os dados demográficos não foram diferentes entre os grupos. A colocação do DSG e a ventilação adequada foram bem-sucedidas em todas as tentativas. A visão da glote adequada para a IGFO diferiu entre os dispositivos, variou de 40% para o TL, 66% para a ML Supreme, 70% para a ML I-Gel e 90% para ambas as máscaras laríngeas Unique e AuraOnce. Conclusão: Nenhum dos DSG usados ofereceu uma visão total ou parcial da glote em todos os casos. Porém, as máscaras laríngeas Unique e AuraOnce pareceram mais adequadas para a IGFO em comparação com os outros dispositivos.

Voice- and health-related quality of life in the elderly.

OBJECTIVE: Restrictions of verbal communication and high prevalence of voice disorders in the elderly are suspected to influence the quality of life. For assessment, both voice-specific and unspecific methods are already established and fundamental components of clinical diagnostics, but the question of correlation between voice-related and general health-related quality of life is still open in this subpopulation. METHODS: One hundred and seven socially active persons aged 65+ years were recruited and asked to complete Voice-Related Quality of Life (V-RQOL) and Short Form (SF)-36 questionnaires. RESULTS: There was a mild correlation between V-RQOL score and both of the SF-36 subscores (r(s)=0.28 for the physical subscore and r(s)=0.27 for the mental subscore). CONCLUSION: As correlation of voice- and health-related quality of life in elderly persons is only mild, both voice-specific and unspecific assessment methods are required for clinical diagnostics.