Upper airway injury and its management

Injuries to the upper airways are rare, but carry a significant morbidity and mortality. The degree of injury and presentation varies; thus recognition often requires a high index of suspicion based on mechanism. Effective management of laryngotracheal injuries begins with immediate control of the airway whether by orotracheal and surgical route. Definitive management of upper airway injuries relies on an understanding of the anatomy of the larynx, trachea and surrounding structures. Associated injuries are common and must be addressed concomitantly. Postoperative complications are frequent, requiring perioperative vigilance and long-term follow-up to ensure best outcome.     

Temperature distribution in the upper airway after inhalation injury

Objective

The aim of the study was to establish an animal model of laryngeal burn and to investigate the temperature distribution of heated air in the upper airway.

Methods

The animal model was established by inhalation of dry heated air at 80, 160 and 320 °C in 18 healthy, male, adult hybrid dogs. Time for inducing injury was set at 20 min. The distribution of temperatures after heated-air inhalation was examined at different locations including the epiglottis, laryngeal vestibule, vocal folds and trachea.

Results

The temperatures of the heated air decreased to 47.1, 118.4 and 193.8 °C at the laryngeal vestibule and to 39.3, 56.6 and 137.9 °C at the lower margin of vocal folds in the 80, 160 and 320 °C groups, respectively.

Conclusion

Due to its special anatomy and functions, the larynx has different responses to dry heated air at different temperatures. The air temperature decreases markedly when the air arrives at the larynx. By contrast, the larynx has a low capacity for blocking high-temperature air and retaining heat. As a result, high-temperature air often causes more severe injury to the larynx and the lower airway.     

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甲状腺手术后发生呼吸困难的并发症不多见,而一旦发生医患双方对其都不胜其烦。甲状腺术后出血,在颈深筋膜的封闭间隙内形成血肿,压迫气管,引起喉头水肿、呼吸功能障碍;双侧喉返神经损伤后双侧声带内收、声门关闭而通气障碍,导致呼吸困难;长期肿大的甲状腺压迫致气管软化,甲状腺切除后可能发生气管塌陷。甲状腺外科手术治疗效果好而手术并发症少的前提是手术医生熟悉重要的局部解剖,一丝不苟地进行严谨的手术操作。对于有气管狭窄、气管软化的病例应在手术中进行预防性气管切开,可能较甲状腺切除后延迟拔除气管插管更安全。     

Microbial flora of the larynx, trachea, and large intestine of the rat after long-term inhalation of 100 per cent oxygen.

Effects of long-term inhalation of 100 per cent oxygen on the microbial flora of the rat larynx, trachea, and large intestine were studies. Rats were kept 14 days in an atmosphere of 100 per cent oxygen after being conditioned to high oxygen concentrations by exposure to three cycles of 100 per cent oxygen (two days) alternating with 40 percent oxygen (two days). Controls were kept under similar conditions in normal atmosphere. Rats were sacrificed, and at necropsy laryngotracheal swabs and fecal material from the large intestine were obtained and cultured for bacteria and fungi. Streptobacillus moniliformis, the predominant microorganism in the upper tracheas of controls, was not isolated from the oxygen-treated rats. Alpha-hemolytic streptococcus and Staphylococcus albus were present in control rats, but were found less frequently in rats exposed to oxygen. Pseudomonas and Proteus, infrequently isolated from controls, were predominant and sometimes the only microorganisms isolated from oxygen-treated rats. The data indicate that prolonged exposure of the rat to 100 per cent oxygen shifts the microbial flora in the upper respiratory tract from mainly gram-positive to mainly gram-negative bacteria. In contrast, there was no significant difference between the microbial flora in large intestines of control and oxygen-treated rats. The possibility that similar changes may occur in man should be considered when prolonged oxygen therapy is contemplated.     

加强呼吸道管理对吸入性损伤气管切开患者肺部感染的防治作用

目的 了解加强呼吸道管理措施对吸入性损伤气管切开患者肺部感染的防治效果.方法 将笔者单位2000年1月--2004年12月收治的14例烧伤伴吸入性损伤患者设为对照组,予以常规全身治疗及常规呼吸道管理;2005年1月-2009年10月收治的27例烧伤伴吸入性损伤患者设为加强组,予以常规全身治疗并加强呼吸道管理,具体措施包括呼吸道"床边隔离"与双管(给氧管、湿化管)固定、体位"定向"湿化与痰液稀释、气道灌洗与程序式排痰、药物联合雾化治疗、"间断负压法"吸痰等.对比观察2组患者的痰液(气管切开后第7天)细菌培养结果、胸部X线片检查(入院后即刻和气管切开后第7天)结果、肺部感染情况、SO_2和血气分析指标(气管切开后7 d内)以及各组患者治愈率. 结果 (1)对照组患者中11例痰液细菌培养呈阳性占78.6%、加强组12例呈阳性占44.4%,组间比较,差异有统计学意义(X~2=4.36,P<0.05).均以铜绿假单胞菌为主要检出菌.(2)胸部X线片提示,加强组7例患者发生肺炎占25.9%,明显少于对照组(8例,占57.1%,X~2=3.87,P<0.05).肺部感染确诊结果与此一致.(3)2组患者观察期间均未出现CO_2潴留现象,无窒息引起的PaCO_2、SO_2异常,PaCO_2值组间接近(t=0.89,P>0.05).(4)对照组治愈9例占64.3%,死亡5例,分别死于肺炎、创面脓毒症、MODS.加强组治愈25例占92.6%,死亡2例,死亡原因均为MODS.加强组治愈率明显高于对照组(X~2=5.22,P<0.05). 结论 加强呼吸道管理措施对气道起到较好的滤过及隔离、湿化作用,便于痰液稀释、引流与排出,减少了盲目吸痰的概率与操作性损伤.有利于防治气管切开后继发的肺部感染.     

Pretreatment airway management in obstructing carcinoma of the larynx

Partial endoscopic excision of obstructing laryngeal carcinoma with the CO2 laser is an alternative to emergency tracheotomy or emergency laryngectomy whenever the airway control can be initially ensured by endotracheal intubation. The practical advantages of this approach are elimination of the septic complications of tracheotomy, the opportunity for planned preoperative chemotherapy or radiation therapy, and better nutritional and psychologic preparation of the patient for surgery.     

Upper airway diseases and airway management: a synopsis

This article summarizes some of the more important upper airway conditions likely to affect airway management. A number of upper airway conditions may present difficult challenges to the anesthesiologist. For instance, infected airway structures may lead to partial airway obstruction, stridor, or even complete airway obstruction. Partial airway obstruction may be mild, as in snoring or nasal congestion, or may be more severe, perhaps requiring the use of airway adjuncts, such as a nasopharyngeal airway. Complete airway obstruction is usually managed by prompt intubation, but surgical airways are sometimes needed as a last resort.     

Congenital calcification of the larynx and trachea

The fifth case of diffuse laryngeal and tracheal cartilage calcification in infancy is reported. The previously reported cases are briefly described. Differential diagnosis and potential etiologies are discussed. It is thought that these patients represent a rare but distinct clinical entity.     

Respiratory management of inhalation injury

Advances in the care of patients with major burns have led to a reduction in mortality and a change in the cause of their death. Burn shock, which accounted for almost 20 percent of burn deaths in the 1930s and 1940s, is now treated with early, vigorous fluid resuscitation and is only rarely a cause of death. Burn wound sepsis, which emerged as the primary cause of mortality once burn shock decreased in importance, has been brought under control with the use of topical antibiotics and aggressive surgical debridement. Inhalation injury has now become the most frequent cause of death in burn patients. Although mortality from smoke inhalation alone is low (0-11 percent), smoke inhalation in combination with cutaneous burns is fatal in 30 to 90 percent of patients. It has been recently reported that the presence of inhalation injury increases burn mortality by 20 percent and that inhalation injury predisposes to pneumonia. Pneumonia has been shown to independently increase burn mortality by 40 percent, and the combination of inhalation injury and pneumonia leads to a 60 percent increase in deaths. Children and the elderly are especially prone to pneumonia due to a limited physiologic reserve. It is imperative that a well organized, protocol driven approach to respiratory care of inhalation injury be utilized so that improvements can be made and the morbidity and mortality associated with inhalation injury be reduced.     

Esophageal reconstruction for hypopharyngoesophageal strictures after corrosive injury.

OBJECTIVE: To evaluate the surgical outcome of patients with caustic stricture of the hypopharyngoesophagus. MATERIALS AND METHODS: During a 25-year period, we performed esophageal reconstruction in 152 patients with diffuse or multiple caustic esophageal stricture. Of them, esophageal substitute was pulled up and anastomosed to the hypopharynx in 50 (33%) patients, and anastomosed to the cervical esophagus in the other 102 (67%) patients. Patients whose esophageal substitute anastomosed to the hypopharynx were enrolled to the present study. Among these 50 study patients, 13 underwent ablation of damaged organs and feeding jejunostomy in acute stage of corrosive injury, and the remaining 37 patients were initially organ preserved with or without feeding gastrostomy or jejunostomy. Six patients had respiratory distress caused by laryngotracheal stricture. The ileocolon (28/50) was commonly used as an esophageal substitute in reconstruction and most substitutes (43/50) went through the substernal route. RESULTS: There was one operative death. Eight (16%) patients had major early postoperative complications. Six patients underwent revision for late stenosis of hypopharyngeal anastomosis, and one redoing reconstruction using the jejunum because of failure of the transplanted ileocolon. Postoperatively, swallow function and maintaining body weight were considered good in 42 patients (84%) after an average of 8 months follow-up. Five of six patients who underwent concomitant tracheostomy or laryngosurgery for laryngotracheal stricture got unsatisfactory result. The surgical outcome of the study patients was worse than that in patients with esophageal substitute anastomosed to a healthy cervical esophagus. In the later group of patients, 95/102 (93%) had good swallow function and only 7/102 (6.8%) had major early complications. CONCLUSION: Caustic stricture of the hypopharyngoesophagus is a challenging reconstructive problem. A successful reconstruction requires a correct hypopharyngeal opening and anastomosis, a good esophageal substitute, and a patent esophageal route and airway.     

Management of larynx and trachea donors

INTRODUCTION: Laryngeal transplantation is a possibility for patients with irreversible laryngeal disease, such as complex trauma and larynx cancer. The objective of performing this procedure was to solve problems that these patients face with a laryngectomy. The medical literature has reviews about larynx transplantations, but almost nothing about the larynx donor. The following is our experience on management of these donors. MATERIALS AND METHODS: Selection criteria was as follows: (1) 18-50 years old; (2) gender and ABO blood type matched between donor and recipient; (3) No abuse of tobacco, cocaine, and marijuana, (4) tracheal intubation time <3 days; and (5) time in the intensive care unit <7 days. The preservation was simple hypothermia with larynx infusion via the carotid artery with University of Wisconsin solution. RESULTS: Between 2001 and 2006, we managed 25 donors, among whom 12 grafts were discarded. The 13 larynx donors were of average age 27.2 +- 7.9 years and their cause of death was head trauma. Each was of male and 12 were multiorgan donors. Three donors had previous consumption of tobacco and 2 donors of marijuana. There were 2 cases of acute rejection episodes. Graft survival rate at 2 years was 90%. DISCUSSION: These donors may have differences from other multiorgan donors: (1) they do not require strict fluid management; (2) vasoactive agents may be used in higher doses than in organ donors, and (3) the larynx tolerates hemodynamic instability. It was necessary to use some donors who had used addictive substances, showing that some selection criteria may be flexible. There was no conflict between thoracic surgeons and larynx surgeons. The priority always was for life-saving organs. Family consent was sometimes difficult because of the retrieval times and body donor reconstruction. The larynx surgery retrieval demanded an additional 2-5 hours during routine multiorgan donor surgery, and always the family asked about body reconstruction. The body appearance was always preserved.