Since its introduction into the Uni...

Since its introduction into the United States almost 20 years ago, flexible bronchoscopy has arguably become the invasive act most frequently performed by chest physicians. The ready acceptance of this management is probably based not simply on its high diagnostic utility, on the other hand also on its low complication rate.[1,2] Complications of flexible bronchoscopy can generally be divided into complications of the bronchoscopic examination and biopsy manner of proceedings (for example, hypoxemia, airway obstruction, bleeding, pneumothorax) and adverse results of medications used before and during the bronchoscopic manner of proceeding In fact, adverse reactions to medications probably account for at least half of the serious morbidity and the rare mortality associated with flexible bronchoscopy[13] Although mild systemic sedation with unsalable articles such as midazolam or meperidine is commonly exerciseed for flexible bronchoscopy, the step can be performed in prefered patients without any systemic sedative pre-medication.[4] However, one as well as the other pre-treatment with atropine to decrease secretions and obviate vasovagal reactions and adequate topical airway anesthesia are generally considered essential for satisfactory bronchoscopy popularly lidocaine is the topical anesthestic of choice for bronchoscopic acts Three pertinent issues related to lidocaine anesthesia for flexible bronchoscopy are: (1) effectiveness of lidocaine in inducing airway anethesia, (2) potential issues of lidocaine "contamination" of bronchoscopic specimens, and (3) the safety of lidocaine administration.

Extensive clinical experience would indicate that lidocaine is an effective topical anesthetic for bronchoscopy and studies have documented the effectiveness of lidocaine for inducing airway anesthesia.[5-8] Lidocaine can be delivered to the upper airways according to spraying via an atomizer, according to ultrasonic or jet nebulization, and by way of the use of lidocaine as a jelly or viscous solution. Anesthesia of the lower airways is generally induced via injection of lidocaine between the sides of the bronchoscope channel. Interestingly, systemic administration of lidocaine can also induce a certain quantity of degree of airway anesthesia.[9] The duration of airway anesthesia induced by way of topical lidocaine is approximately 20-40 minutes [810] and in our experience, inhalation of lidocaine aerosol can achieve airway anesthesia down to the flat of the mid-trachea.

Lidocaine is at hand in many bronchoscopic specimens[11,12] and therefore might alter the issues of in vitro studies forward these specimens, especially microbiologic studies. Although lidocaine (even without preservative) can inhibit the germination of aerobic and anaerobic bacteria, fungi, and mycobacteria in vitro,[13,14] the concentrations of lidocaine measured in bronchoalveolar lavage (BAL) fluid and harbored brush catheter specimens are generally well below the reported minimal inhibitory concentrations for these organisms. Lidocaine can also impair the metabolic function of alveolar macrophages and other immunocompetent confined apartments when studied in vitro,[15,16] further again, the concentrations of lidocaine measured in BAL fluid have generally been lower than the evens of lidocaine required to have significant drifts on these cells when studied in vitro.

Adverse general intents of lidocaine include hypersensitivity reactions, toxicity caused from excessive lidocaine blood levels, and bronchoconstrictor reactions to inhaled lidocaine aerosols. Hypersensitivity to lidocaine is well documented and can be catastrophic.[1,3,17,18] Fortunately, hypersensitivity reactions to lidocaine are rare. Toxic family levels of lidocaine can meet the eye during bronchoscopy[6,19] and result primarily from direct administration of lidocaine to the tracheobronchial mucosa. Inhalation of lidocaine aerosols proceeds in only minimal drug absorption with same low measured blood levels.[5,6,8] As documented according to McAlpine and Thomson in this issue (see page 1012) inhalation of nebulized lidocaine can cause significant bronchoconstriction in patients with asthma. As the authors note, previous studies have documented bronchoconstrictor replys to inhaled lidocaine in patients with hyper-responsive airways disease, although this has not been a universal finding.[10] sum of two units of the findings of these authors of particular interest are the lack of correlation between lidocaine-induced bronchoconstriction and airway reply to histamine, and the prevalence of significant bronchoconstrictor rejoinders to lidocaine in their consideration population. The lack of statisical correlation between lidocaine-induced bronchoconstriction and histamine responsiveness may simply ruminate the small sample size, and sole one patient with what would generally be considered mild histamine responsiveness[20] had a significant answer to lidocaine inhalation. Also, although there is generally a correlation between airway answers to various nonspecific stimuli (for example histamine and methacholine),[21] near authors have found poor correlation with other stimuli as it is as ultrasonically nebulized distilled water.[22,23] In the three controls studied with lidocaine both with and without preservative, there appeared to be no important issue of the preservative per se Although the 25 percent prevalence of significant bronchoconstrictor replications to inhaled lidocaine in this thought is within the range of that reported in previous studies, this is not our experience in above 2,400 bronchoscopic procedures performed in our laboratory. Indeed, we have not noted clinical exacerbation of asthma caused by way of lidocaine inhalation in any patient. This is probably because greatest in number bronchoscopists are less inclined to use the bronchoscope in patients with moderate or bitter clinical asthma. In addition, we have routinely added a beta-agonist (metaproterenol or albuterol) to the lidocaine solution to be inhaled for all patients with any history of airway disease,[8] and it present the appearances likely that this practice will preclude most bronchoconstrictor reactions to the inhaled lidocaine. Nevertheless, while lidocaine anesthesia of the airways for bronchoscopy is generally safe and effective, the article by means of McAlpine and Thomson reminds us that equal routine procedures should be performed with care and forethought.