Invasive pulmonary aspergillosis usually develops in severely immunocompromised patients, such as transplantation recipients, those with malignancy, or those with acquired immunodeficiency disorders. Among these patients, tracheobronchial aspergillosis is rare [1, 2]. It has been suggested that invasive tracheobronchial aspergillosis may lead to fatal hemorrhage because of the development of a bronchovascular fistula [1, 2]. In this case, the tracheobronchial blood clot may have been due to the development of a bronchovascular fistula. However, we cannot be certain of this fact.
The check valve mechanism of airway obstruction is a condition usually associated with the aspiration of an exogenous foreign body . However, in this case, the cause of the tension pneumothorax was considered to be the check valve formation by a blood clot mixed with numerous fungal hyphae in the carina. Brennan et al. reported a case of check valve airway obstruction by a blood clot . In addition, Kadota et al. suggested that the check valve mechanism caused by a presence of granulation tissue plugging the bronchiole lumens may be a leading cause of pneumothorax and cyst formation in patients with organizing pneumonia . Moreover, Söllmann et al. reported a blood clot-like foreign body interspersed with Aspergillus hyphae obstructing the distal chip of the tracheal tube with a check valve-like formation, which led to tension pneumothorax after anesthesia induction . In this case, it is reasonable to believe that the blood clot composed of numerous fungal hyphae in the carina caused the check valve mechanism of the airway, which led to overextension of the lung and eventually to tension pneumothorax. This leading mechanism for tension pneumothorax may have been accelerated by positive-pressure ventilation; however, tension pneumothorax itself could have already developed under spontaneous breathing prior to positive-pressure ventilation because of the strength of the patient’s respiratory effort.
In this case, it is clear that suffocation due to complete airway occlusion could be avoided by positive-pressure ventilation; however, failure in obtaining an escape route for the trapped air was a serious problem. Although the risk of positive pressure ventilation causing distal air trapping by a check valve mechanism has been suggested in case of a foreign body [6, 7], it has also been suggested that there is no clear clinical evidence in the literature surveyed to support this as a practical concern . Therefore, no consensus has been reached regarding the development of critical air trapping due to a check valve formation. When expiratory volume is largely mismatched with inspiratory volume due to a check valve mechanism, severe air trapping can be a leading cause of cardiopulmonary failure, whether it is tension pneumothorax or lung hyperinflation. Moreover, it may be controversial to initiate emergent chest decompression prior to confirmation of tension pneumothorax. Recently, a case report suggested that needle thoracocentesis, particularly at the second rib space in the mid-clavicular line, had high failure rates and potentially serious complications . However, it may be reasonable to consider thoracentesis, which has been recently recommended to be performed in the mid-anterior axillary line of the third–fifth intercostal space , when cardiopulmonary failure is accompanied by air trapping by a check valve mechanism. In severe cases of cardiopulmonary failure due to complete airway obstruction by a foreign body, extracorporeal membrane oxygenation may be considered according to expert opinions . However, there is no guideline or expert opinion available for cardiopulmonary failure by air trapping due to a check valve mechanism. In such a case, it is worthwhile to attempt thoracentesis prior to cardiopulmonary bypass so that no time is lost in establishing an escape route for trapped air. This may be the case particularly in patients with strongly suspected airway bleeding, such as the circumstance in this case.