Patients who develop acute respiratory failure require hospitalization and mechanical ventilatory support. Of all patients admitted to intensive care units in the US, approximately 40% require mechanical ventilation. With the ongoing COVID-19 pandemic, approximately 18% of affected patients are expected to require mechanical ventilation.
Mechanical ventilation requires endotracheal intubation (cannulation of the patient's trachea) to deliver ventilated air to the lungs. Air is delivered by the ventilator to the patient using positive pressure in a closed circuit, ensuring adequate tidal volume to the patient without air escape to the outside environment. Nevertheless, patients placed on mechanical ventilation often develop superimposed infections known as "Ventilator-Associated Pneumonia" (VAP) as well as significant mucus secretions which limit effective mechanical ventilation. A camera tipped device is used to enable more effective bronchoscopy to visualize and explore the tracheobronchial tree for both diagnostic (bacterial/viral sampling) and therapeutic (suctioning obstructive mucus secretions, delivery of therapeutic agents) purposes.
Despite clear diagnostic and therapeutic benefits, bronchoscopy is also associated with substantial morbidity and complications. To perform bronchoscopy, a standard (commercially available) adapter allows the bronchoscope to enter the closed ventilation circuit, providing direct access to the patient's airways. However, the standard adapter leads to a significant leak of tidal volume outside of the ventilation circuit to the ambient environment. This air leak from the adapter leads to two major complications: First, the loss of positive pressure ventilation to patients means that oxygen is not being delivered to the patient and therefore leads to hypoxemia, which limits the duration and efficacy of bronchoscopy. Second, escaped air from the ventilator circuit can lead to the generation of aerosols, which can lead to the significant spread of viral and bacterial infectious agents to the ambient environment and surrounding healthcare providers. Intensive care units (ICUs) in the US must employ negative pressure ventilation to limit pathogen spread outside of the room and to the rest of the ICU. ICU rooms equipped with standard room negative pressure ventilation require 46 minutes after bronchoscopy to clear 99% of aerosolized pathogens. Thus, despite the known diagnostic and therapeutic benefits of bronchoscopy, concerns surrounding viral exposure related to an air leak from bronchoscopy adapters led to the development of national guidelines that limited bronchoscopy in patients affected by Covid-19.
To overcome these limitations, the investigators developed a novel bronchoscope adapter capable of effectively limiting all tidal volume loss (i.e., air leak via adapter) associated with the currently available standard adapters. In ex-vivo and animal studies, the investigators noted that a significant portion of tidal volume delivered by the ventilator is lost to the ambient air when using the standard bronchoscope adapter using the standard adapter (\~40%). There was no tidal volume loss associated with the Leak-free bronchoscope adapter. The innovation in this adapter's development lies in the capacity to form an improved seal around the bronchoscope that limits tidal volume loss around the bronchoscope and captures air that escapes the circuit with the insertion and removal of the bronchoscope. Of note, the adapter is positioned outside the circuit and is only a conduit for the bronchoscope to enter the circuit.
Here the investigators propose a comparative effectiveness study that evaluates the leak-free bronchoscope adapter's use to enable bronchoscopy similar to the standard adapter. Additionally, the investigators will evaluate the adapter's capacity to deliver either equivalent tidal volume to the currently available adapter in patients undergoing bronchoscopy.
