Roland Hofbauer

Comparison of Conventional Surgical versus Seldinger Technique Emergency Cricothyrotomy Performed by Inexperienced Clinicians

Background: Cricothyrotomy is the ultimate option for a patient with a life-threatening airway problem. Methods: The authors compared the first-time performance of surgical (group 1) versus Seldinger technique (group 2) cricothyrotomy in cadavers. Intensive care unit physicians (n = 20) performed each procedure on two adult human cadavers. Methods were compared with regard to ease of use and anatomy of the neck of the cadaver. Times to location of the cricothyroid membrane, to tracheal puncture, and to the first ventilation were recorded. Each participant was allowed only one attempt per procedure. A pathologist dissected the neck of each patient and assessed correctness of position of the tube and any injury inflicted. Subjective assessment of technique and cadaver on a visual analog scale from 1 (easiest) to 5 (worst) was conducted by the performer. Results: Age, height, and weight of the cadavers were not different. Subjective assessment of both methods (2.2 in group 1 vs. 2.4 in group 2) and anatomy of the cadavers (2.2 in group 1 vs. 2.4 in group 2) showed no statistically significant difference between both groups. Tracheal placement of the tube was achieved in 70% (n = 14) in group 1 versus 60% (n = 12) in group 2 (P value not significant). Five attempts in group 2 had to be aborted because of kinking of the guide wire. Time intervals (mean ± SD) were from start to location of the cricothyroid membrane 7 ± 9 s (group 1) versus 8 ± 7 s (group 2), to tracheal puncture 46 ± 37 s (group 1) versus 30 ± 28 s (group 2), and to first ventilation 102 ± 42 s (group 1) versus 100 ± 46 s (group 2) (P value not significant). Conclusions: The two methods showed equally poor performance.

Comparison of a conventional tracheal airway with the Combitube in an urban emergency medical services system run by physicians

This prospective randomised study was performed to compare the use of the Esophageal-Tracheal Combitube(R) (ETC; Tyco Healthcare, Mansfield, MA; http://www.combitube.org) with a conventional tracheal airway (ETA) for airway management by experienced physicians of the Emergency Medical Services System of the City of Vienna in the prehospital setting. Access to the patients head, time of arrival of the ambulance, ease of insertion, time of insertion, potential substitution by the alternate airway, efficacy of adrenaline (epinephrine) administered via the airway, survival to the intensive care unit (ICU) ward and survival to discharge from the hospital were evaluated. One hundred and seventy-two non-traumatic cardiac arrest patients (131 males, 41 females) were enrolled in this study during a 12 months period. In 83 patients (48.3%), the conventional ETA (group 1) was used for the initial intubation attempt which was successful in 78 patients (94%). The remaining five patients of group 1 could not be intubated with an ETA, but were successfully managed with the ETC. Eighty-nine patients (51.7%) were intubated with the ETC (group 2) as first choice (79 in oesophageal position (89%); eight in tracheal position: (9%)), which was successful in 87 (98%) patients. The remaining two patients in group 2 (2%) were successfully managed with the ETA. Success of intubation and ventilation with ETC was comparable to the ETA. Recorded time of insertion was shorter with the ETC versus ETA (P<0.05). The Combitube worked well in cases of difficult access to the patients head and in bleeding and vomiting patients. Both devices served as successful substitutes for each other. Adrenaline (epinephrine) applied via ETC with a 10-fold dosage was as effective as via the conventional ETA. To our knowledge this is the first study using physicians comparing ETC and ETA in the prehospital setting.

Evaluation of Seldinger technique Emergency cricothyroidotomy versus standard surgical cricothyroidotomy in 200 cadavers

Background: Percutaneous cricothyroidotomy is a lifesaving procedure for airway obstruction in trauma victims who need airway establishment and cannot be intubated or in whom intubation has failed. Methods: The purpose of this study was to examine whether there is a training effect using Seldinger technique emergency cricothyroidotomy (group 1; Arndt Emergency Cricothyroidotomy Catheter Set; Cook Critical Care, Bloomington, IN) versus standard surgical cricothyroidotomy (group 2). Twenty emergency physicians performed five cricothyroidotomies with each method in a total of 200 human cadavers, comparing efficacy and safety (speed, success rate, and injuries). Results: Seven attempts in group 1 and six in group 2 had to be aborted. Time intervals from the start of the procedure to location of the cricothyroid membrane were not significantly different between the groups. However, time to tracheal puncture (P < 0.01) and time to first ventilation (P < 0.001) were significantly longer in group 2. No time effect could be observed in both groups. The airway was accurately placed into the trachea through the cricothyroid membrane in 88.2% (82 of 93) of the cadavers in group 1 and in 84.0% (79 of 94) in group 2 (not significant). No injuries were observed in group 1, whereas there were six punctures of the thyroid vessels in group 2 (P < 0.05). Conclusions: With respect to time needed for the procedure, the participants performed Seldinger technique emergency cricothyroidotomy significantly faster as compared with standard surgical cricothyroidotomy. Even if no training effect had been observed, the authors believe that it is important to train residents in different methods of cricothyroidotomy in cadavers in addition to training in mannequins to achieve a higher level of efficacy in real-life situations. The shorter time to first ventilation and the fact that no injuries could be observed favor the Seldinger technique.

Tumor necrosis factor α promotes the expression of stem cell factor in synovial fibroblasts and their capacity to induce mast cell chemotaxis

OBJECTIVE To investigate the expression of the stroma cell product stem cell factor (SCF) in synovial fibroblasts (SFB) in patients with rheumatoid arthritis (RA) and osteoarthritis (OA), and to analyze the capacity of SFB to induce mast cell (MC) chemotaxis. METHODS Synovial tissue was obtained from 29 patients with RA and 25 patients with OA. Tissue was dispersed by enzymatic digestion using collagenase. SFB were grown in serial passage and exposed to tumor necrosis factor alpha (TNFalpha) or control medium. Expression of SCF in cultured SFB was analyzed by reverse transcription-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and immunostaining. The ability of SFB (supernatants) to induce MC migration was analyzed using a double-chamber chemotaxis assay and the human mast cell line HMC-1. In situ expression of SCF in synovial tissue from patients with RA (n = 6) and OA (n = 6) was examined by double immunohistochemistry using antibodies against SCF and the fibroblast-specific antibody AS02. RESULTS In both RA and OA, cultured SFB were found to express SCF messenger RNA, as assessed by RT-PCR. In addition, the SCF protein was detectable in cell lysates and supernatants of SFB by ELISA. Incubation of SFB with TNFalpha resulted in an increased expression and release of SCF. Recombinant human SCF (rHuSCF) and SFB supernatants induced significant migration of HMC-1 cells above control levels. In addition, exposure of SFB to TNFalpha led to an increased migration of HMC-1, and a blocking anti-SCF antibody inhibited the rHuSCF- and SFB-induced migration of HMC-1. In situ double immunostaining revealed expression of SCF in AS02-positive SFB in the synovium of patients with RA. CONCLUSION Our results show that SFB (in RA and OA) express SCF and induce MC chemotaxis. Furthermore, TNFalpha was found to augment SCF expression in SFB. It is hypothesized that these cellular interactions play an important role in MC accumulation and related events in RA.

Salicylate inhibits LDL oxidation initiated by superoxide/nitric oxide radicals

Simultaneously produced superoxide/nitric oxide radicals (O⋅− 2/NO⋅) could form peroxynitrite (OONO−) which has been found to cause atherogenic, i.e. oxidative modification of LDL. Aromatic hydroxylation and nitration of the aspirin metabolite salicylate by OONO− has been reported. Therefore we tested if salicylate may be able to protect LDL from oxidation by O⋅− 2/NO⋅ by scavenging the OONO− reactive decomposition products. When LDL was exposed to simultaneously produced O⋅− 2/NO⋅ using the sydnonimine SIN‐1, salicylate exerted an inhibitory effect on LDL oxidation as measured by TBARS and lipid hydroperoxide formation and alteration in electrophoretic mobility of LDL. The cytotoxic effect of SIN‐1 pre‐oxidised LDL to endothelial cells was also diminished when salicylate was present during SIN‐1 treatment of LDL. Spectrophotometric analysis revealed that salicylate was converted to dihydroxybenzoic acid (DHBA) derivatives in the presence of SIN‐1. 2,3‐ and 2,5‐DHBA were even more effective to protect LDL from oxidation by O⋅− 2/NO⋅. Because O⋅− 2/NO⋅ can occur in vivo, the results may indicate that salicylate could act as an efficacious inhibitor of O⋅− 2/NO⋅ initiated atherogenic LDL modification, thus further supporting the rationale of aspirin medication regarding cardiovascular diseases.

Sufentanil inhibits migration of human leukocytes through human endothelial cell monolayers.

The interactions between blood and vascular wall cells are essential for understanding pathophysiological processes, e.g., during inflammation. The influence of anesthetics on leukocyte function is well documented. An inhibitory effect of thiopental, midazolam, and ketamine on leukocyte chemotaxis in a Boyden chamber chemotaxis assay (i.e., endothelial cells were not included) has been demonstrated. Little is known, however, about the influence of sufentanil on the inflammatory processes. To reach their targets in the tissue in vivo, leukocytes must interact with endothelial cell monolayers (ECMs). The aim of the current study was to investigate the influence of sufentanil on the migration of leukocytes through an ECM. Human umbilical vein endothelial cells were cultured to achieve a monolayer. Isolated polymorphonuclear leukocytes and ECM were preincubated with different concentrations of sufentanil. The rate of leukocyte migration against the chemotactic protein formyl-methyl-leucyl-phenylalanine was measured (n = 7). Sufentanil significantly reduced the amount of leukocyte migration through ECM to 77% +/- 7.8% (P < 0.05 compared with control). Endothelial cells as well as leukocytes contributed to this effect: treatment of both cell types showed an additive effect. Although lower concentrations showed no effect, high concentrations reduced leukocyte migration through ECM to 61% +/- 7.1%. Implications: Leukocytes play an important role during inflammation, and anesthetics influence leukocyte functions, e.g., respiratory burst or chemotaxis. The effect of sufentanil on transendothelial leukocyte migration has not been investigated. Therefore, we used a migration assay including endothelial cell monolayers. Sufentanil showed a reducing effect on transendothelial leukocyte migration. (Anesth Analg 1998;87:1181-5)

Genistein prevents the glucose autoxidation mediated atherogenic modification of low density lipoprotein.

Hyperglycemia has been assumed to be responsible for oxidative stress in diabetes. In this respect, glucose autoxidation and advanced glycation end products (AGE) may play a causal role in the etiology of diabetic complications as e.g. atherosclerosis. There is now growing evidence that the oxidative modification of LDL plays a potential role in atherogenesis. Glucose derived oxidants have been shown to peroxidise LDL. In the present study, genistein, a compound derived from soy with a flavonoid chemical structure (4′, 5, 7-trihydroxyisoflavone) has been evaluated for its ability to act as an antioxidant against the atherogenic modification of LDL by glucose autoxidation radical products. Daidzein, (4′, 7-dihydroxyisoflavone) an other phytoestrogen of soy, was tested in parallel. Genistein — in contrast to daidzein — effectively prevented the glucose mediated LDL oxidation as measured by thiobarbituric acid-reactive substance formation (TBARS), alteration in electrophoretic mobility, lipid hydroperoxides and fluorescence quenching of tryptophan residues of the lipoprotein. In addition the potential of glucose-oxidized LDL to increase tissue factor (TF) synthesis in human endothelial cells (HUVEC) was completely inhibited when genistein was present during LDL oxidative modification by glucose. Both phytoestrogens did not influence the nonenzymatic protein glycation reaction as measured by the in vitro formation of glycated LDL. As the protective effect of genistein on LDL atherogenic modification was found at glucose/genistein molar ratios which may occur in vivo, our findings support the suggested beneficial action of a soy diet in preventing chronic vascular diseases and early atherogenic events.

Propofol reduces the migration of human leukocytes through endothelial cell monolayers

OBJECTIVE To test propofol and the solvent of propofol on leukocyte function in the presence of endothelial cell monolayers. The interactions of leukocytes with endothelial cells play a tremendous role during inflammation. Previous studies have investigated the influence of propofol on leukocytes. DESIGN Prospective, controlled study. SETTING University research laboratories. SUBJECTS Seven independent experiments were performed to investigate the influence of propofol (0.4, 4, and 40 ng/mL) on the migration of human leukocytes through human endothelial cell monolayers. Moreover, the authors tested the solvent of propofol on leukocyte migration. INTERVENTIONS Human endothelial cell monolayers and/or human leukocytes were preincubated with clinically relevant higher and lower concentrations of propofol. The amount of leukocyte migration after 3 hrs was measured with a fluorometer. MEASUREMENTS AND MAIN RESULTS Human endothelial cells isolated from umbilical veins were cultured on microporous membranes until they formed an endothelial cell monolayer. Leukocytes were separated by standard procedures. The migration of leukocytes through monolayers of endothelial cells using the clinically relevant concentration of propofol was reduced to 93% +- 3.8% (so; p < .05) when the leukocytes but not the endothelial cell monolayers were preincubated with propofol. Leukocyte migration was reduced to 80% - 5.9% (p < .05) when only monolayers of endothelial cells were treated with propofol, and was reduced to 73% + 10.4% (p < .05) when both leukocytes and monolayers of endothelial cells were treated with propofol. The higher and lower concentrations showed a dose-dependent effect. The solvent of propofol had no significant effect. CONCLUSION The authors investigated the influence of propofol and its solvent on the interaction between both cell systems-leukocytes and endothelial cells. Propofol is able to reduce significantly the migration of leukocytes through endothelial cell monolayers. The use of different doses revealed a dose-dependent effect. The current model allowed treatment of one cell type: leukocyte or endothelial cell. The results of this investigation indicate that the influence of propofol on leukocyte migration affects endothelial cells more than leukocytes.

Hydroxyethyl starch reduces the chemotaxis of white cells through endothelial cell monolayers

BACKGROUND: Polymorphonuclear leukocytes (PMNs) play a tremendous role during inflammatory processes. PMNs have to pass a monolayer of endothelial cells to migrate into the extravascular space. Hydroxyethyl starch (HES) is frequently used as a volume expander in critically ill patients.

Ibuprofen inhibits leukocyte migration through endothelial cell monolayers.

During inflammation leukocytes are playing a tremendous role in the defense against bacterial infections. Tumor necrosis factor alpha (TNF alpha) increases adhesion of leukocytes to endothelial cells. The non steroidal anti-inflammatory drug ibuprofen is able to reduce inflammatory processes in humans and is a widely used drug. The influence of ibuprofen on TNF-alpha-induced expression of adhesion molecules on endothelial cells is well investigated and has been published recently by our group. For leukocyte migration, leukocytes have to attach and finally migrate through monolayers of endothelial cells. The aim of the current study was to investigate leukocyte migration through endothelial cell monolayers (ECM) under ibuprofen using a migration assay system. Ibuprofen was identified as a potent inhibitor of the leukocyte migration through endothelial cell monolayers in a dose dependent manner. The treatment of either leukocytes (87 +/- 17.6 %; p>0.05) or endothelial cell monolayers (62.5 +/- 9.4 %; p<0.05) showed that the influence is more mediated through endothelial cells, the treatment of both cell types demonstrated an additive effect. In conclusion, the previously published changes of adhesion molecules on endothelial cells could be confirmed with this functional migration test. The inhibition of the leukocyte migration may contribute to the anti-inflammatory actions of the drug.