Electromyography as a new means of navigation during endotracheal intubation

Abstract

This study tested a method of using rapid analysis of electromyographic response patterns to electrical stimulation to enable real-time navigation during endotracheal intubation. An electromyographic response detection device was constructed and integrated into a standard endotracheal tube. The rebound rates of the response voltages were measured in the trachea and oesophagus after stimulation in an acute study performed in three freshly euthanized male Suffolk sheep. In a blind study, a physician attempted to identify the tissue type solely from the electrical response signals. In the acute study, the observed rebound rate was found to be significantly faster in tracheal tissue (2.21?×?10^?3 V s^?1) than in oesophageal tissue (3.45?×?10^?2 V s^?1; p?=?0.000 05). In the blind study, the physician correctly determined the oesophagus response rate seven out of eight times and the tracheal rate eight out of nine times. These results suggest that electromyographic responses can be used to accurately differentiate tracheal from oesophageal tissue during ETT insertion, thus offering a valuable new means of enhancing patient safety.     

Management of esophageal stenting-associated esophagotracheal fistula,tracheal stenosis and tracheal rupture: a case report and review of the literature

Objective: Although the placement of esophageal self-expandable stents (SES) can effectively relieve dysphagia after radiotherapy in patients with esophageal cancer (EC), it may induce severe esophageal complications. This article reports a case of emergency endotracheal intubation in an EC patient who suddenly developed severe dyspnea two months after SES placement. Methods: Electronic bronchoscopy of the patient’s airway confirmed the diagnosis of esophagotracheal fistula, tracheal stenosis and tracheal rupture. Endotracheal intubation was successfully performed under the guidance of electronic bronchoscopy. Results: Dyspnea due to tracheal stenosis was relieved effectively by inserting the tracheal catheter to a proper place under the guidance of electronic bronchoscopy. Conclusion: Bronchoscopic examination is strongly recommended in EC patients who are highly suspected as having airway stenosis associated with esophageal stenting, for which endotracheal intubation under the guidance of bronchoscopy is suggested.     

Inhibition of p38 MAPK Reduces Expression of Vascular Endothelial Growth Factor in Allergic Airway Disease

Background

The p38 mitogen-activated protein kinase (MAPK) appears to play an important role in various pathophysiological responses and has been suggested to be involved in many processes considered critical to the inflammatory response and tissue remodeling. Bronchial asthma is a chronic inflammatory disorder of the airway accompanied by increased vascular permeability. Vascular endothelial growth factor (VEGF) is a potent stimulator of bronchial inflammation, airway remodeling, and physiologic dysregulation that augments antigen sensitization and T-helper type 2 cell (Th2)-mediated inflammation in allergic airway diseases. However, there are little data on the relationship between p38 MAPK signaling and VEGF expression in allergic airway disease.

Objective

This study aimed to investigate the role of p38 MAPK on the pathogenesis of allergic airway disease, more specifically in VEGF expression.

Methods

Using ovalbumin (OVA)-inhaled mice and a selective p38 MAPK inhibitor, SB 239063, the involvement of p38 MAPK in allergen-induced VEGF expression in the airway was evaluated.

Results

The increases of phosphorylation of p38 MAPK, VEGF protein expression, and vascular permeability in the lung after OVA inhalation were decreased substantially by the administration of SB 239063. In addition, SB 239063 significantly reduced the increase of Th2 cytokines and OVA-specific IgE. The inhibition of p38 MAPK or VEGF signaling prevented and also decreased the increases in the number of inflammatory cells and airway hyperresponsiveness in OVA-induced allergic airway disease.

Conclusions

These results indicate that inhibition of p38 MAPK may attenuate allergen-induced airway inflammation and vascular leakage through modulation of VEGF expression in mice.     

Hyperresponsiveness of bronchial but not tracheal smooth muscle in a murine model of allergic bronchial asthma

Objective: To determine a change in airway smooth muscle contractility in a murine model of allergic asthma, the responsiveness of airway smooth muscles isolated from ovalbumin (OA)-sensitized and -challenged mice was compared with that from control animals.Methods: Actively sensitized mice were repeatedly challenged by ovalbumin (OA) antigen inhalation. Twenty-four h after the last antigen challenge, tracheal and bronchial smooth muscle responsiveness to acetylcholine (ACh) and endothelin-1 (ET-1) were measured. Airway microvascular leakage and histochemistry were also determined as indices of airway inflammation.Results: Both the ACh and ET-1 responsiveness of bronchial, but not tracheal, smooth muscles were significantly augmented in OA-challenged mice, whereas no significant change in the expression levels of M₂, M₃ and ET_B receptors was observed. The Evans blue dye extravasation in the main bronchial, but not tracheal, tissue of OA-challenged mice was significantly increased as compared with that of sensitized control animals. A marked inflammatory cells infiltration was also observed in bronchial but not tracheal tissues of OA-challenged mice.Conclusion: Repeated antigen challenge to sensitized mice caused a hyperresponsiveness of bronchial, but not tracheal, smooth muscle accompanied with bronchial tissue inflammation.Received 22 April 2004; returned for revision 10 June 2004; accepted by M. Katori 9 July 2004     

广州市院前急救医护人员气管插管技能调查

目的了解广州市院前急救医护人员气管插管技能掌握情况。方法对2008年3～6月参加广州市院前急救规范化培训的医护人员共216人进行调查分析。结果广州市院前急救医护人员总体气管插管技能掌握率偏低（51.9%）,其中医生气管插管掌握率为74.1%,而护士掌握率为29.6%（P〈0.001）;三级医院院前急救医生比二级医院院前急救医生气管插管技能掌握率高（88.2%vs50%,P〈0.001）;部分医院（18.5%）仍然以麻醉科医生气管插管为主;98.1%的医院急救车未配备喉罩或联合导管等备用高级气道装置。结论广州院前急救医护人员气管插管技能掌握率低,不同级别医院医护人员气管插管掌握存在较大差异,需要加强气管插管技能的规范化统一培训,从而真正提高广州市院前急救的整体水平。     

Administration of Pigment Epithelium-Derived Factor Inhibits Airway Inflammation and Remodeling in Chronic OVA-Induced Mice via VEGF Suppression

Purpose

Pigment epithelium-derived factor (PEDF) is a recently discovered antiangiogenesis protein. PEDF possesses powerful anti-inflammatory, antioxidative, antiangiogenic, and antifibrosis properties. It has been reported that PEDF can regulate vascular endothelial growth factor (VEGF) expression. This study aimed to evaluate whether recombinant PEDF protein could attenuate allergic airway inflammation and airway remodeling via the negative regulation of VEGF using a murine model of chronic ovalbumin (OVA)-induced asthma and BEAS-2B human bronchial epithelial cells.

Methods

In an in vivo experiment, mice sensitized with OVA were chronically airway challenged with aerosolized 1% OVA solution for 8 weeks. Treated mice were given injections of recombinant PEDF protein (50 or 100 µg/kg body weight) via the tail vein. In an in vitro experiment, we investigated the effects of recombinant PEDF protein on VEGF release levels in BEAS-2B cells stimulated with IL-1β.

Results

Recombinant PEDF protein significantly inhibited eosinophilic airway inflammation, airway hyperresponsiveness, and airway remodeling, including goblet cell hyperplasia, subepithelial collagen deposition, and airway smooth muscle hypertrophy. In addition, recombinant PEDF protein suppressed the enhanced expression of VEGF protein in lung tissue and bronchoalveolar lavage fluid (BALF) in OVA-challenged chronically allergic mice. In the in vitro experiment, VEGF expression was increased after IL-1β stimulation. Pretreatment with 50 and 100 ng/mL of recombinant PEDF protein significantly attenuated the increase in VEGF release levels in a concentration-dependent manner in BEAS-2B cells stimulated by IL-1β.

Conclusions

These results suggest that recombinant PEDF protein may abolish the development of characteristic features of chronic allergic asthma via VEGF suppression, providing a potential treatment option for chronic airway inflammation diseases such as asthma.     

新型pH敏感性材料及其给药系统在现代药剂学中的应用进展

 目的 探讨血管内皮生长因子（VEGF）在结直肠癌组织中的表达及其作为肿瘤新生血管标志的临床价值。 方法 采用免疫人VEGF单克隆抗体及鼠抗人因子Ⅷ相关抗原（F-8 RAg）单克隆抗体，通过免疫组化技术对48例结直肠癌手术切除的癌组织及癌旁正常组织（对照组织）中VEGF和F-8 RAg的表达进行检测。 结果 结直肠癌组织VEGF表达阳性率为62.5%（30/48），对照组为16.7%（8/48），χ²＝64.352，P<0.01。结直肠癌组织F-8 RAg标记的MVD为100.9 ± 16.0，对照组为46.8 ± 11.9，t =18.351，P<0.01。VEGF的表达与大肠癌的淋巴结转移（P<0.01）、远处转移（P<0.05）及临床分期有关（P=0.01）；而F-8 RAg标记的MVD与大肠癌的淋巴结转移、远处转移及临床分期无明显相关（P>0.05）。VEGF在结肠癌组织的表达与F-8 RAg的表达无相关性（P>0.05）。 结论 VEGF在结直肠癌组织新生血管有良好表达，可以作为结直肠癌新生血管有价值的标志     

Tracheal Wall Thickening Is Associated with the Granulation Tissue Formation Around Silicone Stents in Patients with Post-Tuberculosis Tracheal Stenosis

Purpose

Tracheal restenosis due to excessive granulation tissue around a silicone stent requires repeated bronchoscopic interventions in patients with post-tuberculosis tracheal stenosis (PTTS). The current study was conducted to identify the risk factors for granulation tissue formation after silicone stenting in PTTS patients.

Materials and Methods

A retrospective study was conducted between January 1998 and December 2010. Forty-two PTTS patients with silicone stenting were selected. Clinical and radiological variables were retrospectively collected and analyzed.

Results

Tracheal restenosis due to granulation tissue formation were found in 20 patients (47.6%), and repeated bronchoscopic interventions were conducted. In multivariate analysis, tracheal wall thickness, measured on axial computed tomography scan, was independently associated with granulation tissue formation after silicone stenting. Furthermore, the degree of tracheal wall thickness was well correlated with the degree of granulation tissue formation.

Conclusion

Tracheal wall thickening was associated with granulation tissue formation around silicone stents in patients with post-tuberculosis tracheal stenosis.     

The Role of Vascular Endothelial Growth Factor (VEGF) in Abnormal Vascular Changes in the Adult Rat Eye

Abstract

The aim of this project was to determine if the subretinal delivery of a recombinant adenovirus encoding vascular endothelial growth factor (VEGF) was sufficient to induce changes resembling choroidal neovascularisation (CNV) in a rat model. A recombinant adenovirus was produced encoding vegf¹⁶⁴ cDNA (Ad.RSV.VEGF). Transduction of cultured RPE cells confirmed VEGF expression and ensured the absence of Ad.RSV.VEGF-related toxicity. Following subretinal injection into rat eyes, fluorescein angiography indicated that the in vivo delivery of Ad.RSV.VEGF was associated with vascular leakage. Histological analysis demonstrated that changes resembling the early signs of CNV development were also present in the Ad.RSV.VEGF injected eyes. These results suggest that while a transient VEGF expression in the RPE layer is able to induce CNV-related changes, it may be insufficient for the development of a full neovascular membrane. This study demonstrates that virus-mediated gene delivery, in addition to its clinical applications, is a potentially efficient research tool for investigating gene expression-related physiological changes in vitro and in vivo.     

Role of angiogenic factors in airway remodeling in an allergic rhinitis murine model

Purpose

There is growing evidence that nasal airway remodeling occurs in allergic rhinitis (AR). Although angiogenesis is an important component of airway remodeling in asthma, its involvement in AR has been little studied. Furthermore, information regarding the role of potent angiogenic factors, such as vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF), in the nasal airway remodeling process is limited. This study was conducted to investigate the role of VEGF and PDGF in nasal airway remodeling, and to assess the preventive effects of anti-angiogenic drugs on this process in a murine AR model.

Methods

Mice were systemically sensitized and subjected to inhalation of ovalbumin (OVA) twice a week for 3 months. Control mice were challenged with phosphate buffered saline, while the treatment group received SU1498, a VEGF receptor inhibitor, and/or AG1296, a PDGF receptor inhibitor, via intraperitoneal injection 4 hours prior to each OVA inhalation. Staining using hematoxylin and eosin, Masson''s trichrome, and periodic acid-Schiff were separately performed to assess eosinophil infiltration, subepithelial fibrosis, and goblet cell hyperplasia, respectively, in the nasal airway. Immunohistochemical staining for matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) was also conducted.

Results

Repetitive intranasal inhalation of OVA resulted in significant increases in eosinophil infiltration, subepithelial fibrosis, goblet cell count, and MMP-9/TIMP-1 expression. Administration of SU1498 or AG1296 prevented these abnormal responses.

Conclusions

The results of this study suggest that a causal relationship may exist between angiogenic factors and nasal airway remodeling in AR. Inhibition of VEGF or PDGF receptors may, in turn, suppress the remodeling process through the regulation of MMP-9/TIMP-1 expression.     

Expression of vascular endothelial growth factor (VEGF) and its two receptors (VEGF-R1-Flt1 and VEGF-R2-Flk1/KDR) in non-small cell lung carcinomas (NSCLCs): correlation with angiogenesis and survival

The formation of new vessels (angiogenesis) is essential for primary tumour growth and metastasis and is induced by several angiogenic factors, including vascular endothelial growth factor (VEGF). The microvascular density (MVD) in tumours was assessed and the expression of VEGF and its receptors VEGF-R1-Flt1 and VEGF-R2-KDR/Flk1 was investigated in the different cellular compartments in vivo, in order to establish their interrelationship and their prognostic influence. Immunohistochemical study of 69 stage I–II non-small cell lung carcinomas (NSCLCs) was performed on paraffin sections with CD34 antibody to estimate MVD, using a Chalkley eye-piece graticule and VEGF, VEGF-R1, and VEGF-R2 antibodies. There was strong expression of VEGF and its receptors in tumour cells, endothelial cells, and stromal fibroblasts. In tumour cells, the level of VEGF was correlated with that of VEGF-R1 ( p = 0·018) but not that of VEGF-R2. In fibroblasts, high expression of VEGF was correlated with that of VEGF-R1 ( p = 0·0001) and VEGF-R2 ( p = 0·0001). In endothelial cells, expression of VEGF was correlated with that of VEGF-R1 ( p < 0·0001) and VEGF-R2 ( p = 0·04). The level of VEGF in fibroblasts was correlated with that of VEGF-R1 ( p = 0·0028) and VEGF-R2 ( p = 0·01) in endothelial cells. There was no correlation between the level of MVD and that of VEGF or VEGF-R1 or VEGF-R2. Neither the level of MVD, nor the level of expression of VEGF and VEGF receptors in any compartment influenced the patient's survival. In conclusion, although angiogenesis is essential for tumour growth, this study failed to demonstrate that MVD, VEGF, VEGF-R1, and VEGF-R2 are prognostic markers for stage I–II NSCLC. VEGF, however, might act as a direct autocrine growth factor for tumour cells via VEGF-R1 and angiogenesis could be promoted in a paracrine loop, where VEGF is produced by fibroblasts and tumour cells and then binds to endothelial cells via induced VEGF receptors. VEGF and its receptors thus appear as relevant therapeutic targets in NSCLC. Copyright © 1999 John Wiley & Sons, Ltd.     

Comparison of the TruView infant EVO2 PCD™ and C-MAC video laryngoscopes with direct Macintosh laryngoscopy for routine tracheal intubation in infants with normal airways

OBJECTIVE:

Videolaryngoscopy has mainly been developed to facilitate difficult airway intubation. However, there is a lack of studies demonstrating this method''s efficacy in pediatric patients. The aim of the present study was to compare the TruView infant EVO2 and the C-MAC videolaryngoscope with conventional direct Macintosh laryngoscopy in children with a bodyweight ≤10 kg in terms of intubation conditions and the time to intubation.

METHODS:

In total, 65 children with a bodyweight ≤10 kg (0-22 months) who had undergone elective surgery requiring endotracheal intubation were retrospectively analyzed. Our database was screened for intubations with the TruView infant EVO2, the C-MAC videolaryngoscope, and conventional direct Macintosh laryngoscopy. The intubation conditions, the time to intubation, and the oxygen saturation before and after intubation were monitored, and demographic data were recorded. Only children with a bodyweight ≤10 kg were included in the analysis.

RESULTS:

A total of 23 children were intubated using the C-MAC videolaryngoscope, and 22 children were intubated using the TruView EVO2. Additionally, 20 children were intubated using a standard Macintosh blade. The time required for tracheal intubation was significantly longer using the TruView EVO2 (52 sec vs. 28 sec for C-MAC vs. 26 sec for direct LG). However, no significant difference in oxygen saturation was found after intubation.

CONCLUSION:

All devices allowed excellent visualization of the vocal cords, but the time to intubation was prolonged when the TruView EVO2 was used. The absence of a decline in oxygen saturation may be due to apneic oxygenation via the TruView scope and may provide a margin of safety. In sum, the use of the TruView by a well-trained anesthetist may be an alternative for difficult airway management in pediatric patients.     

Post intubation tracheal stenosis

Tracheal stenosis following prolonged intubation is a relatively rare but a serious problem. However, some degree of airway injury is common following intubation, no matter whether it is prolonged or of short duration. Here, we are reporting a fifty six year old male patient who developed multiple web like tracheal stenosis following intubation with high volume low pressure cuff endotracheal tube. Subsequently, the stenosis was successfully dilated by balloon bronchoplasty.     

Association of vascular endothelial growth factor and mast cells with angiogenesis in laryngeal squamous cell carcinoma

We investigated the expression of vascular endothelial growth factor (VEGF) and microvascular density in 54 cases of invasive laryngeal squamous cell carcinoma (SCC) and in ten samples of normal laryngeal tissue using immunohistochemistry methods. The study also focused on the distribution of mast cells in and around the SCCs. The microvascular density in laryngeal carcinoma tissue was higher than that in normal tissue (P=0.02). VEGF was localized in SCCs, stromal cells, endothelial cells, minor salivary glands, and non-cancer epithelium adjacent to the tumor. VEGF expression in the tumor cells was found in 13 of 54 cases (24.1%), whereas mast cells around the carcinomas were VEGF positive in all 54 cases. Staining of VEGF in SCCs was strong in the area of high microvascular density (P=0.0002). Using a multi-labeling subtraction immunostaining method, VEGF-positive stromal cells were classified mostly as mast cells and, in a few instances, as macrophages. VEGF staining in SCCs was associated with the mast cell count (P=0.0001). There was no distinct correlation between VEGF expression and pTNM stage of an SCC. In conclusion, the results suggest that VEGF might be an important angiogenic factor in cancer invasion. Laryngeal cancer cells and mast cells may control the angiogenic response by releasing VEGF. Received: 22 March 1999 / Accepted: 14 September 1999     

Topical pluronic F-127 gel application enhances cutaneous wound healing in rats

Pluronic F-127 gel is used as vehicle for various topical applications. In the present study, effects of topical application of pluronic F-127 gel were evaluated in cutaneous wound healing in Wistar rats. Normal saline solution and pluronic F-127 gel (25%) were applied topically on open excision wounds for 14 days. Photography, determination of percentage wound contraction, and collection of granulation tissue were done on days 3, 7, 11 and 14 post-wounding. Topical application of gel (once daily) significantly increased the wound closure on days 11 and 14. The gel application increased the expressions of vascular endothelial growth factor (VEGF) and transforming growth factor-beta1 (TGF-β₁) on days 3 and 7. Histopathologically, more leukocyte infiltration followed by well formed granulation tissue with marked fibroblast proliferation was evident in the gel-treated group, as compared to the saline-treated control group. Immunohistochemistry of CD31 on day 7 revealed significant higher microvessel density in gel-treated wounds. Picrosirius staining demonstrated higher collagen fraction in gel-treated wounds. Thus, from the results, it could be concluded that pluronic F-127 gel has a mild inflammatory nature and enhanced the healing by stimulating expression of VEGF and TGF-β₁.     

Antimicrobial properties of distinctin in an experimental model of MRSA-infected wounds

The aim of this study was to evaluate the efficacy of distinctin in the management of cutaneous methicillin-resistant Staphylococcus aureus (MRSA) wound infections in an experimental mouse model. Wounds, made in the panniculus carnosus of BALB/c mice, were inoculated with 5?×?10⁷ colony-forming units (CFU) of MRSA. Mice were treated with topical distinctin (1?mg/kg of body weight), topical teicoplanin (7?mg/kg of body weight), intraperitoneal teicoplanin (7?mg/kg of body weight); topical teicoplanin and daily intraperitoneal teicoplanin; topical distinctin and daily intraperitoneal teicoplanin. Bacterial cultures of excised tissues and histological examination of microvessel density and of vascular endothelial growth factor (VEGF) expression were studied. It was found that topical distinctin combined with parenteral teicoplanin inhibited bacterial growth to levels comparable with those observed in uninfected animals. Wounded areas of animals treated with distinctin were characterized by a more mature granulation tissue, with a more organized and denser type of connective tissue, compared to mice treated only with teicoplanin. Treatment with topical distinctin had a significant impact on VEGF expression and microvessel density. The combined use of distinctin with teicoplanin may be useful in the management of infected wounds by significantly inhibiting bacterial growth and accelerating the repair process.     

Obstructive Fibrinous Tracheal Pseudomembrane After Tracheal Intubation: A Case Report

Obstructive fibrinous tracheal pseudomembrane is a rare, but potentially fatal complication associated with endotracheal intubation. It has been known that the formation of tracheal pseudomembrane is related with intracuff pressure during endotracheal intubation or infectious cause. But in the patient described in this case, pseudomembrane formation in the trachea was associated with subglottic epithelial trauma or caustic injuries to the trachea caused by aspirated gastric contents during intubation rather than tracheal ischemia due to high cuff pressure. We report a patient with obstructive fibrinous tracheal pseudomembrane after endotracheal intubation who presented with dyspnea and stridor and was treated successfully with mechanical removal using rigid bronchoscopy.