Ventilatory pattern variability as a biometric for severity of acute lung injury in rats.

We hypothesize that ventilatory pattern variability (VPV) varies with the magnitude of acute lung injury (ALI). In adult male rats, we instilled a low- or high- dose of bleomycin or saline (PBS) intratracheally. While representative samples of pulmonary tissue indicated graded lung injury, coefficient of variation (CV) of TTOT did not differ among the 3 groups. Broncho-alveolar lavage fluid (BALF), respiratory rate (fR), mutual information were greater in ALI than sham rats; but did not differ between bleomycin doses. However, nonlinear complexity index (NLCI), which is the difference in sample entropy between original and surrogate data sets was greater for high- versus low- dose; but did not differ between low-dose and sham groups. Further, NLCI correlated to an injury index based on protein concentration of BALF and failure to gain weight. Finally, Receiver Operator Curves (ROCs) indicated that both mutual information and NLCI had greater sensitivity and specificity than fR and CVTTOT in identifying ALI. Thus, nonlinear analyses of VPV can distinguish ALI and out performs fR as a biometric.

Application of 3D Printing for Patient-Specific Silicone Stents: 1-Year Follow-Up on 2 Patients.

Managing complex benign airway disease is a major challenge in interventional pulmonology. Airway stent placement can result in complications due to a variety of factors, including poor fit of the stent in the airway. We report the 1-year outcome of 2 patients with airway disease caused by granulomatosis with polyangiitis (Wegener's) affecting the left main bronchus and secondary carina. These patients had not responded to systemic therapy or standard bronchoscopic techniques and had complications with commercially available airway stents. We describe a first-in-human, clinical experience to address these issues. Using computed tomography (CT) imaging and 3D printing technology, we generated and implanted patient-specific silicone airway stents to address airway disease. 3D patient-specific stent prescription was created using a CT scan of the patient's chest and a proprietary software package originally developed for orthopedic surgical planning. Silicone stents were manufactured and implanted. Observation for > 1 year after implantation compared to the 6 months prior to patient-specific stent implant were compared for the number, clinically required stent changes, procedure time, and general clinical improvement per usual standard of care after airway stenting. Patients showed improved durability, a shorter procedure time, and improvement of patient-reported symptoms leading to a reduced need for stent changes and modifications. The use of 3D printing technology to make patient-specific silicone stents is feasible with early clinical proof of concept noting a durable improvement over 1 year of follow-up.