Reaction products of hexamethylene diisocyanate vapors with “self” molecules in the airways of rabbits exposed via tracheostomy

1.?Hexamethylenediisocyanate (HDI) is a widely used aliphatic diisocyanate and a well-recognized cause of occupational asthma.

2.?“Self” molecules (peptides/proteins) in the lower airways, susceptible to chemical reactivity with HDI, have been hypothesized to play a role in asthma pathogenesis and/or chemical metabolism, but remain poorly characterized.

3.?This study employed unique approaches to identify and characterize “self” targets of HDI reactivity in the lower airways. Anesthetized rabbits free breathed through a tracheostomy tube connected to chambers containing either, O₂, or O₂ plus ～200 ppb HDI vapors. Following 60 minutes of exposure, the airways were lavaged and the fluid was analyzed by LC-MS and LC-MS/MS.

4.?The low-molecular weight (<3?kDa) fraction of HDI exposed, but not control rabbit bronchoalveolar lavage (BAL) fluid identified 783.26 and 476.18 m/z [M+H]⁺ ions with high energy collision-induced dissociation (HCD) fragmentation patterns consistent with bis glutathione (GSH)-HDI and mono(GSH)-HDI. Proteomic analyses of the high molecular weight (>3?kDa) fraction of exposed rabbit BAL fluid identified HDI modification of specific lysines in uteroglobin (aka clara cell protein) and albumin.

5.?In summary, this study utilized a unique approach to chemical vapor exposure in rabbits, to identify HDI reaction products with “self” molecules in the lower airways.     

The Case of the Retained Stone

Abstract

Tracheostomies have become a typical component of the management of patients with prolonged respiratory failure. There are, however, relatively few studies from which to establish an accepted standard of care with regard to the specific features, daily care, and removal of tracheostomy tubes. Consequently, these decisions are sometimes guided by myth and misconception. In this article, we review the different types of tracheostomy tubes with their respective advantages and disadvantages, basic principles of care, recognition of complications, speech with a tracheostomy tube, and the process by which they may sometimes be removed.     

Children with a tracheostomy: experience of their carers in school

OBJECTIVE: Tracheostomies in children are increasingly performed for chronic medical conditions. There are no published studies reporting the experience of children with a tracheostomy in school. Such information would be valuable in planning the care and education of these children. The aims of this study were to identify those children with a tracheostomy in Nottinghamshire schools and determine the support they were receiving. DESIGN, SETTING AND PARTICIPANTS: Questionnaire survey to families and school carers of 11 children with a tracheostomy. RESULTS: All children of school age were in full-time education (five mainstream, five special schools). One preschool child attended a Family Centre. Four had problems finding suitable carers, delaying return to school in three. Four parents were dissatisfied with aspects of the child's experience at school: two felt the teaching staff were unsupportive, one was unhappy with the care of the tracheostomy, and one had problems funding a carer. Ten out of 11 school carers were satisfied with their training; 10 would have liked regular update sessions. The amount of care required varied. Those with complex medical problems in a special school setting needed frequent care, and one had required admission to hospital from school. One child had time off school because of lack of carer availability. Those who were severely disabled had less time off school for ill health after the tracheostomy than before the tracheostomy. CONCLUSION: Children with tracheostomies can successfully and safely achieve full-time education in both mainstream and special schools. A dedicated multidisciplinary team, including input from the parents, is essential to achieve this goal. Regular revision of skills and information sessions for the teaching staff would be beneficial.     

Minitracheotomy Seldinger—assessment of a new technique

A multicentre, prospective study of 26 patients was undertaken for the assessment of insertion of minitracheotomy tubes by the Seldinger technique. The technique of insertion is described. There were two misplacements, three blockages of the inserting Tuohy needle with fat, and six cases of difficulty in passing the minitracheotomy tube.     

单步经皮旋转气管切开术式改进在急危重患者中的应用

目的探讨单步经皮旋转气管切开术式的改进在急危重患者中抢救的应用前景和价值。方法选取2007年3月以来经治的35例各种原因致呼吸道梗阻而引起的呼吸极度困难患者为观察对象,应用单步经皮旋转气管切开术的基本术式,借鉴PDT穿刺技术替代床边纤支镜引导下直视穿刺方法,即在第1,2或2,3软骨环水平横行切开皮肤,切口长度=螺旋切开器的外径×π/2(切口长度=切割器周长/2,精确计算可减少损伤。),套管针接注射器后垂直穿刺进针(注射器内有2%利多卡因2 ml),同时回抽注射器,见有气泡就确定进入气管中。拔除针芯,置入导丝。将旋转切割器沿导丝旋入,退出切割器,置入气管导管即可。结果应用改进后的气管切开方法实施的手术,使患者均顺利建立了人工气道而获救,由于手术方法的改进有效地避免了纤支镜自身侵入性操作对气管壁损伤,减少了设备,简化了手术步骤,达到了床边纤支镜引导同等效果。结论改进后单步经皮旋转气管切开的术式更安全,可控性更强,准确性更高,更易于非外科专业技术人员操作,值得推广。     

经皮气管切开技术的演变及启示

经皮气管切开技术是一种微创的气管切开技术,具有操作简单,快捷、并发症少、安全和效价比高等特点目前在世界范围得到了广泛临床推广和应用。回顾经皮气管切开技术的演变过程我们可以得到很多有益的启迪,有助于我们去开拓和创新更适于危重病人的微创经皮气管切开技术。     

Safety of percutaneous dilational tracheostomy in hematopoietic stem cell transplantation recipients requiring long-term mechanical ventilation

Purpose

Recent reports have shown that the outcome of mechanically ventilated patients after hematopoietic stem cell transplantation (HSCT) has improved. This study was conducted to clarify if percutaneous dilational tracheostomy is safe in this group of patients and to report the outcome of HSCT recipients requiring long-term mechanical ventilation.

Methods

A retrospective review of our 8-year experience with patients with acute respiratory insufficiency after HSCT, requiring long-term mechanical ventilation and percutaneous dilational tracheostomy and an analysis of patient outcomes were made.

Results

Percutaneous dilational tracheostomy was safely performed in all 51 patients. Although 1 patient (2%) developed a pneumothorax that required drainage, stoma infections or severe bleeding complications were not observed. Of the 51 patients in the study, 14 (27%) survived the intensive care unit stay, and 10 of them were ventilated for more than 20 days. The intensive care unit survival rate for the period from 1998 to 2001 was 11% compared with 38% for the period from 2002 to 2005 (P = .053).

Conclusions

Percutaneous dilational tracheostomy can be safely performed on patients with acute respiratory failure after HSCT. This procedure did not result in postoperative wound infections or significant bleeding complications. Furthermore, the results of our study indicate that today even patients with prolonged mechanical ventilation (>20 days) have a chance of long-term survival.     

Permanent tracheostomy for long-term respiratory studies

BACKGROUND: We describe a modified surgical technique for permanent, anterior tracheal-wall stoma for chronic, repeat respiratory studies in trained, conscious dogs. These cannula-free tracheostomies require minimal daily maintenance, permit repeat intubation with endotracheal tubes modified for airflow respiratory measurement, and facilitate up to 6 h continuous administration of aerosol agents during long-term or repeat respiratory studies. METHODS: In 20 dogs, during a 30 to 40 min procedure, portions of tracheal rings 2-4 were removed to create an oval stoma, approximately 2 x 1 cm. The dermis was secured to the transected cartilage and tracheal mucosa in such a manner that skin covered the sternohyoid muscles and grew-in flush with the tracheal mucosa at the stomal opening. Stomas were cleaned daily, and fur was clipped weekly around the stomal site. No other maintenance procedures or environmental modifications were needed. Animals breathed through both the stoma and the upper airway and barked normally. RESULTS: Stomas remained viable in long-term animals (n = 4) ongoing for 70.3 +/- 32.2 mo (mean +/- SEM), with an ongoing maximum of 126 mo. Postmortem examinations were performed on shorter-term animals (n = 16) sacrificed at 16.7 +/- 7.3 mo. Thirteen showed no appreciable tracheal stenosis and three showed <10% stenosis at the level of the stoma. Histopathological examination of the stomal opening and surrounding tissue revealed minimal chronic inflammation and no evidence of necrosis or infection. CONCLUSIONS: During long-term respiratory studies, this practical and dependable tracheal stoma provides a means for examining acute and chronic effects of environmental and pathophysiological influences on the respiratory system of conscious dogs.     

Assessment of healthcare professionals' knowledge of managing emergency complications in patients with a tracheostomy

Background: Ear, nose, and throat (ENT) surgeons perform the majority ofsurgical tracheostomies. Intensive care anaesthetists are increasinglyperforming bedside percutaneous tracheostomy. The objectivesof this study were to characterize emergency complications oftracheostomy and to ascertain healthcare professionals’knowledge of life-saving strategies for the patient with a tracheostomy. Methods: Seventy staff members in two large teaching hospitals completedan interview questionnaire, comprising a simple clinical scenarioand unambiguous questions regarding the emergency managementof patients with a tracheostomy. Results: There were significant gaps in knowledge among healthcare professionalsregarding the management of specific tracheostomy-related emergencies. Conclusions: Knowledge of tracheostomy-related emergencies appears to beinsufficient among non-ENT healthcare professionals. This needsto be addressed in order to maximize patient safety.