Case 6--1992. Alternative technique for laser resection of a carinal obstruction

The anesthesia of trachea and bronchus surgery

The trachea and bronchus surgery is generally performed due to stenosis, traumatic injury, foreign body and tumors. Preoperative evaluation and anesthesia management are very important issues because of higher mortality and morbidity rates. Patients may be asymptomatic, but airway difficulties, hypoxia, stridor, cough, hemoptysis are common conditions in these patient population. The collaboration between the surgeon and the anesthesiologist is very substantial and necessary. Anesthetic techniques include various applications such as one lung ventilation, fiberoptic intubation, jet ventilation, and apneic oxygenation, general anesthesia with or without neuromuscular blockade. In this review, anesthesia management of the trachea and bronchus surgery is evaluated in the light of new knowledge.

Developments in general airway management

Since the 1970s, improvements in airway management have been significant. New imaging modalities such as CT and MRI can display airway structures with unparalleled detail, which improves preoperative planning and the treatment of patients with pathologic processes involving the respiratory tract or with difficult-to-manage airways. Because of the introduction of flexible fiberscopes, pulmonologists and thoracic surgeons can diagnose diseases of the respiratory tract effectively and treat patients with these diseases safely. The use of flexible fiberscopes has expanded rapidly into other medical specialties, including anesthesia and critical care. Modem anesthesiologists now use flexible fiberscopes daily to intubate patients safely, especially when traditional intubating techniques fail. The cost of fiberscopes has decreased dramatically, and their optical systems have improved. Several centers of excellence have been developed where clinicians can learn basic and advanced techniques of fiberoptic intubation. The LMA has shown that the supraglottic airway approach is not only feasible, but also in many situations superior to tracheal intubation. Although the LMA initially was recommended as an alternative to the facemask, its use has expanded, benefiting many children and adults undergoing a variety of diagnostic and therapeutic procedures. Use of an LMA in combination with a flexible fiberscope has opened up new possibilities for treating patients safely and effectively while providing optimal comfort during a procedure and has been particularly beneficial in thoracic surgery. The most recent iteration of the ASA Difficult Airway Algorithm has revised further a systematic approach to the clinical care of patients with different types of difficult-to-manage airways.

Anesthesia for airway surgery

Surgery of the upper airway requires diagnostic or therapeutic manipulation of the respiratory tree despite ongoing ventilation. Whether internal or external access to the conducting airway is required, anesthesiologist and surgeon, who must work together closely, share the airway. The anesthetic technique is influenced by the chosen mode of ventilation.

Laryngeal mask airway for therapeutic fiberoptic bronchoscopic procedures

These cases illustrate the advantages of the laryngeal mask as compared with an endotracheal tube or oxygen face mask for selected patients undergoing therapeutic bronchoscopic procedures. The advantages include a larger internal diameter allowing easier passage of instruments, reduced work of breathing, lack of discomfort associated with insertion, access to the vocal cords and upper trachea unimpeded by the presence of an endotracheal tube, and capnographic and volume monitoring of respiration. The LMA is thus a valuable alternative for airway management in pulmonary compromised patients undergoing therapeutic bronchoscopic procedures.

Anaesthesia for laser pharyngoplasty--a comparison of the tracheal tube with the reinforced laryngeal mask airway

A common cause of snoring is palatal flutter which occurs when turbulent air flow causes the flexible soft palate to flutter. Surgical correction involves either removal of the soft palate or a reduction in its flexibility. Laser pharyngoplasty is a new surgical procedure designed to stiffen the soft palate. It presents a unique combination of problems for the anaesthetist. In this paper we describe the evolution of the anaesthetic technique for laser pharyngoplasty and analyse the results of the first 165 cases. Points of particular interest include the use of the reinforced laryngeal mask airway compared with the tracheal tube and late onset pain.

The incendiary characteristics of the laryngeal and reinforced laryngeal mask airway to CO2 laser strike--a comparison with two polyvinyl chloride tracheal tubes

The incendiary characteristics of the laryngeal and reinforced laryngeal mask airway to the CO2 laser have been compared with two polyvinyl chloride tracheal tubes. Three different power densities (2.35, 4.7 and 9.8 x 10(3) watt/cm2) were used, with either oxygen or a 30% oxygen/70% nitrous oxide mixture flowing down the tube. The laryngeal mask airway (and reinforced model) was shown to be more resistant than the polyvinyl chloride tracheal tubes. The laryngeal mask tube could not be ignited at a power density of 2.25 x 10(3) watt/cm2 after five minutes, although penetration occurred in 20-30 seconds. A layer of silica ash built up at the impact site and protected the underlying tube. The laryngeal mask airway cuff was penetrated at 3 to 5 seconds. At this power density the polyvinyl chloride tube ignited in 2 to 8 seconds and the cuff was penetrated in 0.1 seconds. At the highest power density the tubes of all airways ignited within 0.2 seconds. The possibilities for improving the incendiary characteristics of the laryngeal mask airway are discussed.

The laryngeal mask airway: its features, effects and role

The laryngeal mask airway was designed as a new concept in airway management and has been gaining a firm position in anaesthetic practice. Numerous articles and letters about the device have been published in the last decade, but few large controlled trials have been performed. Despite widespread use, the definitive role of the laryngeal mask has yet to be established. In some situations, such as after failed tracheal intubation or in anaesthesia for patients undergoing laparoscopic or oral surgery, its use is controversial. There are a number of unresolved issues, for example the effect of the laryngeal mask on regurgitation and whether or not cricoid pressure prevents placement of the mask. We review the techniques of insertion, details of misplacement, and complications associated with the use of the laryngeal mask. We discuss the features and physiological effects of the device, including the changes in intra-cuff pressure during anaesthesia and effects on blood pressure, heart rate and intra-ocular pressure. We then attempt to clarify the role of the laryngeal mask in airway management during anaesthesia, based on the current knowledge, by discussing the advantages and disadvantages as well as the indications and contraindications of its use. Lastly we describe the use of the laryngeal mask in circumstances other than airway maintenance during anaesthesia: fibreoptic bronchoscopy, tracheal intubation through the mask and its use in cardiopulmonary resuscitation.