THE TRACHEAL BRONCHUS

Animals in Respiratory Research

The respiratory barrier, a thin epithelial barrier that separates the interior of the human body from the environment, is easily damaged by toxicants, and chronic respiratory diseases are common. It also allows the permeation of drugs for topical treatment. Animal experimentation is used to train medical technicians, evaluate toxicants, and develop inhaled formulations. Species differences in the architecture of the respiratory tract explain why some species are better at predicting human toxicity than others. Some species are useful as disease models. This review describes the anatomical differences between the human and mammalian lungs and lists the characteristics of currently used mammalian models for the most relevant chronic respiratory diseases (asthma, chronic obstructive pulmonary disease, cystic fibrosis, pulmonary hypertension, pulmonary fibrosis, and tuberculosis). The generation of animal models is not easy because they do not develop these diseases spontaneously. Mouse models are common, but other species are more appropriate for some diseases. Zebrafish and fruit flies can help study immunological aspects. It is expected that combinations of in silico, in vitro, and in vivo (mammalian and invertebrate) models will be used in the future for drug development.

An unusual cause of intraoperative hypoxemia

Congenital anomalies of the tracheobronchial tree are rare occurrences; however, they can lead to pulmonary complications. A tracheal bronchus is an anatomic variant in which an ectopic bronchus originates directly from the tracheal wall above the carina. Presented is a case of intraoperative hypoxemia due to right upper lobe collapse. Despite what appeared to be proper endotracheal tube positioning, this clinical scenario was found to be the result of endotracheal tube obstruction of a tracheal bronchus supplying the right upper lobe. Fiberoptic bronchoscopy proved to be a rapid diagnostic and therapeutic tool, as the endotracheal tube was able to be visually positioned above this aberrantly located bronchus.

Bronchial anomaly of the right upper lobe

This case report presents a rare anomaly of right upper lobe bronchial anatomy. During routine right upper lobe resection for carcinoma, a common right upper and middle lobe bronchus was found. The resection was completed as a right upper and middle bilobectomy. Knowledge of this uncommon variant was beneficial in performing the pulmonary resection. A review of the literature is presented.