The effect of pleural drainage on pulse oximetry in a post-operative thoracic surgery population.

BACKGROUND: Pleural effusions in post-operative thoracic surgery patients are common. Effusions can result in prolonged hospitalizations or readmissions, with prior studies suggesting mixed effects of pleural drainage on hypoxia. We aimed to define the impact of pleural drainage on pulse oximetry (SpO2) in post-thoracic surgery patients. METHODS: A retrospective study of post-operative thoracic surgery patients undergoing pleural drainage was performed. SpO2 and supplemental oxygen (FiO2) values were recorded at pre- and post-procedure. The primary outcome was difference in pre-procedural and post-procedural SpO2. RESULTS: We identified 95 patients with a mean age of 65 (SD - 13.8) years undergoing 122 pleural drainage procedures. Mean drainage volume was 619 (SD-423) mL and the majority of procedures (88.5 %) included a drainage of <1000 mL. SpO2 was associated with an increase from 94.0 % (SD-2.6) to 97.3 % (SD-2.0) at 24-h (p < 0.0001). FiO2 was associated with a decrease from 0.31 (SD-0.15) to 0.29 (SD-0.12) at 24-h (p = 0.0081). SpO2/FiO2 was associated with an increase from 344.5 (SD-99.0) to 371.9 (SD-94.7) at 24-h post-procedure (p < 0.0001). CONCLUSIONS: Pleural drainage within post-operative thoracic surgery patients offers statistically significant improvements in oxygen saturation by peripheral pulse oximetry and oxygen supplementation; however the clinical significance of these changes remains unclear. Pleural drainage itself may be requested for numerous reasons, including diagnostic (fevers, leukocytosis, etc.) or therapeutic (worsening dyspnea) evaluation. However, pleural drainage may offer minimal clinical impact on pulse oximetry in post-operative thoracic surgery patients.

Pleural Fluid Resolution Is Associated with Improved Survival in Patients with Malignant Pleural Effusion.

Malignant pleural effusion is associated with a poor prognosis and, while risk stratification models exist, prior studies have not evaluated pleural fluid resolution and its association with survival. We performed a retrospective review of patients diagnosed with malignant pleural effusion between 2013 and 2017, evaluating patient demographics, pleural fluid and serum composition, and procedural and treatment data using Cox regression analysis to evaluate associations with survival. In total, 123 patients were included in the study, with median survival from diagnosis being 4.8 months. Resolution of malignant pleural fluid was associated with a significant survival benefit, even when accounting for factors such as placement of an indwelling pleural catheter, anti-cancer therapy, pleural fluid cytology, cancer pheno/genotypes, and pleural fluid characteristics. Elevated fluid protein, placement of an indwelling pleural catheter, and treatment with targeted or hormone therapies were associated with pleural fluid resolution. We conclude that the resolution of pleural fluid accumulation in patients with malignant pleural effusion is associated with a survival benefit possibility representing a surrogate marker for treatment of the underlying metastatic cancer. These findings support the need to better understand the mechanism of fluid resolution in patients with malignant pleural effusion as well as the tumor-immune interplay occurring with the malignant pleural space.

Landmark Based Bronchoscope Localization for Needle Insertion Under Respiratory Deformation.

Bronchoscopy is currently the least invasive method for definitively diagnosing lung cancer, which kills more people in the United States than any other form of cancer. Successfully diagnosing suspicious lung nodules requires accurate localization of the bronchoscope relative to a planned biopsy site in the airways. This task is challenging because the lung deforms intraoperatively due to respiratory motion, the airways lack photometric features, and the anatomy's appearance is repetitive. In this paper, we introduce a real-time camera-based method for accurately localizing a bronchoscope with respect to a planned needle insertion pose. Our approach uses deep learning and accounts for deformations and overcomes limitations of global pose estimation by estimating pose relative to anatomical landmarks. Specifically, our learned model considers airway bifurcations along the airway wall as landmarks because they are distinct geometric features that do not vary significantly with respiratory motion. We evaluate our method in a simulated dataset of lungs undergoing respiratory motion. The results show that our method generalizes across patients and localizes the bronchoscope with accuracy sufficient to access the smallest clinically-relevant nodules across all levels of respiratory deformation, even in challenging distal airways. Our method could enable physicians to perform more accurate biopsies and serve as a key building block toward accurate autonomous robotic bronchoscopy.

Interventional Pulmonary Fellowship Training: End of the Beginning.

Interventional pulmonology (IP) fellowship training has undergone increased popularity and growth. The Accreditation Council of Graduate Medical Education recently recognized IP medicine as a new subspecialty, which leads to new challenges and opportunities for a young subspecialty. Although the specialty-specific requirements are in progress, IP fellowship programs must plan ahead for the known common program requirements and anticipated accreditation process. The educational leadership in IP must identify and execute solutions to sustain continued excellence. This includes transitioning to a new regulatory environment with issues of funding new fellowships, keeping up to date with training/assessment of new procedures, and shaping the future through recruitment of talent to lead the young subspecialty.

A Multicenter Study Assessing Interventional Pulmonary Fellow Competency in Electromagnetic Navigation Bronchoscopy.

Background: Current medical society guidelines recommend a procedural number for obtaining electromagnetic navigational bronchoscopy (ENB) competency and for institutional volume for training. Objective: To assess learning curves and estimate the number of ENB procedures for interventional pulmonology (IP) fellows to reach competency. Methods: We conducted a prospective multicenter study of IP fellows in the United States learning ENB. A tool previously validated in a similar population was used to assess IP fellows by their local faculty and two blinded independent reviewers using virtual recording of the procedure. Competency was determined by performing three consecutive procedures with a competency score on the assessment tool. Procedural time, faculty global rating scale, and periprocedural complications were also recorded. Results: A total of 184 ENB procedures were available for review with assessment of 26 IP fellows at 16 medical centers. There was a high correlation between the two blinded independent observers (rho = 0.8776). There was substantial agreement for determination of procedural competency between the faculty assessment and blinded reviewers (kappa = 0.7074; confidence interval, 0.5667-0.8482). The number of procedures for reaching competency for ENB bronchoscopy was determined (median, 4; mean, 5; standard deviation, 3.83). There was a wide variation in the number of procedures to reach competency, ranging from 2 to 15 procedures. There were six periprocedural complications reported, four (one pneumomediastinum, three pneumothorax) of which occurred before reaching competence and two pneumothoraces after achieving competence. Conclusion: There is a wide variation in acquiring competency for ENB among IP fellows. Virtual competency assessment has a potential role but needs further studies.

A Direct Comparative Study of Bronchoscopic Navigation Planning Platforms for Peripheral Lung Navigation: The ATLAS Study.

BACKGROUND: The use of mapping to guide peripheral lung navigation (PLN) represents an advance in the management of peripheral pulmonary lesions (PPL). Software has been developed to virtually reconstruct computed tomography images into 3-dimensional airway maps and generate navigation pathways to target PPL. Despite this there remain significant gaps in understanding the factors associated with navigation success and failure including the cartographic performance characteristics of these software algorithms. This study was designed to determine whether differences exist when comparing PLN mapping platforms. METHODS: An observational direct comparison was performed to evaluate navigation planning software packages for the lung. The primary endpoint was distance from the terminal end of the virtual navigation pathway to the target PPL. Secondary endpoints included distal virtual and segmental airway generations built to the target and/or in each lung. RESULTS: Twenty-five patient chest computed tomography scans with 41 PPL were evaluated. Virtual airway and navigation pathway maps were generated for each scan/nodule across all platforms. Virtual navigation pathway comparison revealed differences in the distance from the terminal end of the navigation pathway to the target PPL (robotic bronchoscopy 9.4 mm vs. tip-tracked electromagnetic navigation 14.2 mm vs. catheter based electromagnetic navigation 17.2 mm, P=0.0005) and in the generation of complete distal airway maps. CONCLUSION: Comparing PLN planning software revealed significant differences in the generation of virtual airway and navigation maps. These differences may play an unrecognized role in the accurate PLN and biopsy of PPL. Further prospective trials are needed to quantify the effect of the differences reported.

Electromagnetic Navigation Transthoracic Nodule Localization for Minimally Invasive Thoracic Surgery.

The increased use of chest computed tomography (CT) has led to an increased detection of pulmonary nodules requiring diagnostic evaluation and/or excision. Many of these nodules are identified and excised via minimally invasive thoracic surgery; however, subcentimeter and subsolid nodules are frequently difficult to identify intra-operatively. This can be mitigated by the use of electromagnetic transthoracic needle localization. This protocol delineates the step-by-step process of electromagnetic localization from the pre-operative period to the postoperative period and is an adaptation of the electromagnetically guided percutaneous biopsy previously described by Arias et al. Pre-operative steps include obtaining a same day CT followed by the generation of a three-dimensional virtual map of the lung. From this map, the target lesion(s) and an entry site are chosen. In the operating room, the virtual reconstruction of the lung is then calibrated with the patient and the electromagnetic navigation platform. The patient is then sedated, intubated, and placed in the lateral decubitus position. Using a sterile technique and visualization from multiple views, the needle is inserted into the chest wall at the prechosen skin entry site and driven down to the target lesion. Dye is then injected into the lesion and, then, continuously during needle withdrawal, creating a tract for visualization intra-operatively. This method has many potential benefits when compared to the CT-guided localization, including a decreased radiation exposure and decreased time between the dye injection and the surgery. Dye diffusion from the pathway occurs over time, thereby limiting intra-operative nodule identification. By decreasing the time to surgery, there is a decrease in wait time for the patient, and less time for dye diffusion to occur, resulting in an improvement in nodule localization. When compared to electromagnetic bronchoscopy, airway architecture is no longer a limitation as the target nodule is accessed via a transparenchymal approach. Details of this procedure are described in a step-by-step fashion.

Pleural Interventions in the Management of Hepatic Hydrothorax.

Hepatic hydrothorax can be present in 5% to 15% of patients with underlying cirrhosis and portal hypertension, often reflecting advanced liver disease. Its impact can be variable, because patients may have small pleural effusions and minimal pulmonary symptoms or massive pleural effusions and respiratory failure. Management of hepatic hydrothorax can be difficult because these patients often have a number of comorbidities and potential for complications. Minimal high-quality data are available for guidance specifically related to hepatic hydrothorax, potentially resulting in pulmonary or critical care physician struggling for best management options. We therefore provide a Case-based presentation with management options based on currently available data and opinion. We discuss the role of pleural interventions, including thoracentesis, tube thoracostomy, indwelling tunneled pleural catheter, pleurodesis, and surgical interventions. In general, we recommend that management be conducted within a multidisciplinary team including pulmonology, hepatology, and transplant surgery. Patients with refractory hepatic hydrothorax that are not transplant candidates should be managed with palliative intent; we suggest indwelling tunneled pleural catheter placement unless otherwise contraindicated. For patients with unclear or incomplete hepatology treatment plans or those unable to undergo more definitive procedures, we recommend serial thoracentesis. In patients who are transplant candidates, we often consider serial thoracentesis as a standard treatment, while also evaluating the role indwelling tunneled pleural catheter placement may play within the course of disease and transplant evaluation.

Design Considerations for a Steerable Needle Robot to Maximize Reachable Lung Volume.

Steerable needles that are able to follow curvilinear trajectories and steer around anatomical obstacles are a promising solution for many interventional procedures. In the lung, these needles can be deployed from the tip of a conventional bronchoscope to reach lung lesions for diagnosis. The reach of such a device depends on several design parameters including the bronchoscope diameter, the angle of the piercing device relative to the medial axis of the airway, and the needle's minimum radius of curvature while steering. Assessing the effect of these parameters on the overall system's clinical utility is important in informing future design choices and understanding the capabilities and limitations of the system. In this paper, we analyze the effect of various settings for these three robot parameters on the percentage of the lung that the robot can reach. We combine Monte Carlo random sampling of piercing configurations with a Rapidly-exploring Random Trees based steerable needle motion planner in simulated human lung environments to asymptotically accurately estimate the volume of sites in the lung reachable by the robot. We highlight the importance of each parameter on the overall system's reachable workspace in an effort to motivate future device innovation and highlight design trade-offs.

COVID-19 Impact on Interventional Pulmonology Training.

Background: The impact of the coronavirus disease (COVID-19) pandemic extends beyond the realms of patient care and healthcare resource use to include medical education; however, the repercussions of COVID-19 on the quality of training and trainee perceptions have yet to be explored. Objective: The purpose of this study was to determine the degree of interventional pulmonology (IP) fellows' involvement in the care of COVID-19 and its impact on fellows' clinical education, procedure skills, and postgraduation employment search. Methods: An internet-based survey was validated and distributed among IP fellows in North American fellowship training programs. Results: Of 40 eligible fellows, 38 (95%) completed the survey. A majority of fellows (76%) reported involvement in the care of patients with COVID-19. Fellows training in the Northeast United States reported involvement in the care of a higher number of patients with COVID-19 than in other regions (median, 30 [interquartile range, 20-50] vs. 10 [5-13], respectively; P < 0.01). Fifty-two percent of fellows reported redeployment outside IP during COVID-19, mostly into intensive care units. IP procedure volume decreased by 21% during COVID-19 compared with pre-COVID-19 volume. This decrease was mainly accounted for by a reduction in bronchoscopies. A majority of fellows (82%) reported retainment of outpatient clinics during COVID-19 with the transition from face-to-face to telehealth-predominant format. Continuation of academic and research activities during COVID-19 was reported by 86% and 82% of fellows, respectively. After graduation, all fellows reported having secured employment positions. Conclusion: Although IP fellows were extensively involved in the care of patients with COVID-19, most IP programs retained educational activities through the COVID-19 outbreak. The impact of the decrease in procedure volume on trainee competency would be best addressed individually within each training program. These data may assist in focusing efforts regarding the education of medical trainees during the current and future healthcare crises.

Backward Planning for a Multi-Stage Steerable Needle Lung Robot.

Lung cancer is one of the deadliest types of cancer, and early diagnosis is crucial for successful treatment. Definitively diagnosing lung cancer typically requires biopsy, but current approaches either carry a high procedural risk for the patient or are incapable of reaching many sites of clinical interest in the lung. We present a new sampling-based planning method for a steerable needle lung robot that has the potential to accurately reach targets in most regions of the lung. The robot comprises three stages: a transorally deployed bronchoscope, a sharpened piercing tube (to pierce into the lung parenchyma from the airways), and a steerable needle able to navigate to the target. Planning for the sequential deployment of all three stages under health safety concerns is a challenging task, as each stage depends on the previous one. We introduce a new backward planning approach that starts at the target and advances backwards toward the airways with the goal of finding a piercing site reachable by the bronchoscope. This new strategy enables faster performance by iteratively building a single search tree during the entire computation period, whereas previous forward approaches have relied on repeating this expensive tree construction process many times. Additionally, our method further reduces runtime by employing biased sampling and sample rejection based on geometric constraints. We evaluate this approach using simulation-based studies in anatomical lung models. We demonstrate in comparison with existing techniques that the new approach (i) is more likely to find a path to a target, (ii) is more efficient by reaching targets more than 5 times faster on average, and (iii) arrives at lower-risk paths in shorter time.

Association between Tunneled Pleural Catheter Use and Infection in Patients Immunosuppressed from Antineoplastic Therapy. A Multicenter Study.

Rationale: Patients with malignant or paramalignant pleural effusions (MPEs or PMPEs) may have tunneled pleural catheter (TPC) management withheld because of infection concerns from immunosuppression associated with antineoplastic therapy.Objectives: To determine the rate of infections related to TPC use and to determine the relationship to antineoplastic therapy, immune system competency, and overall survival (OS).Methods: We performed an international, multiinstitutional study of patients with MPEs or PMPEs undergoing TPC management from 2008 to 2016. Patients were stratified by whether or not they underwent antineoplastic therapy and/or whether or not they were immunocompromised. Cumulative incidence functions and multivariable competing risk regression analyses were performed to identify independent predictors of TPC-related infection. Kaplan-Meier method and multivariable Cox proportional hazards modeling were performed to examine for independent effects on OS.Results: A total of 1,408 TPCs were placed in 1,318 patients. Patients had a high frequency of overlap between antineoplastic therapy and an immunocompromised state (75-83%). No difference in the overall (6-7%), deep pleural (3-5%), or superficial (3-4%) TPC-related infection rates between subsets of patients stratified by antineoplastic therapy or immune status was observed. The median time to infection was 41 (interquartile range, 19-87) days after TPC insertion. Multivariable competing risk analyses demonstrated that longer TPC duration was associated with a higher risk of TPC-related infection (subdistribution hazard ratio, 1.03; 95% confidence interval [CI], 1.00-1.06; P = 0.028). Cox proportional hazards analysis showed antineoplastic therapy was associated with better OS (hazard ratio, 0.84; 95% CI, 0.73-0.97; P = 0.015).Conclusions: The risk of TPC-related infection does not appear to be increased by antineoplastic therapy use or an immunocompromised state. The overall rates of infection are low and comparable with those of immunocompetent patients with no relevant antineoplastic therapy. These results support TPC palliation for MPE or PMPEs regardless of plans for antineoplastic therapy.

Management of Indwelling Tunneled Pleural Catheters: A Modified Delphi Consensus Statement.

BACKGROUND: The management of recurrent pleural effusions remains a challenging issue for clinicians. Advances in management have led to increased use of indwelling tunneled pleural catheters (IPC) because of their effectiveness and ease of outpatient placement. However, with the increase in IPC placement there have also been increasing reports of complications, including infections. Currently there is minimal guidance in IPC-related management issues after placement. RESEARCH QUESTION: Our objective was to formulate clinical consensus statements related to perioperative and long-term IPC catheter management based on a modified Delphi process from experts in pleural disease management. STUDY DESIGN AND METHODS: Expert panel members used a modified Delphi process to reach consensus on common perioperative and long-term management options related to IPC use. Members were identified from multiple countries, specialties, and practice settings. A series of meetings and anonymous online surveys were completed. Responses were used to formulate consensus statements among panel experts, using a modified Delphi process. Consensus was defined a priori as greater than 80% agreement among panel constituents. RESULTS: A total of 25 physicians participated in this project. The following topics were addressed during the process: definition of an IPC infection, management of IPC-related infectious complications, interventions to prevent IPC infections, IPC-related obstruction/malfunction management, assessment of IPC removal, and instructions regarding IPC management by patients and caregivers. Strong consensus was obtained on 36 statements. No consensus was obtained on 29 statements. INTERPRETATION: The management of recurrent pleural disease with IPC remains complex and challenging. This statement offers statements for care in numerous areas related to IPC management based on expert consensus and identifies areas that lack consensus. Further studies related to long-term management of IPC are warranted.

Decoupling Steerability from Diameter: Helical Dovetail Laser Patterning for Steerable Needles.

The maximum curvature of a steerable needle in soft tissue is highly sensitive to needle shaft stiffness, which has motivated use of small diameter needles in the past. However, desired needle payloads constrain minimum shaft diameters, and shearing along the needle shaft can occur at small diameters and high curvatures. We provide a new way to adjust needle shaft stiffness (thereby enhancing maximum curvature, i.e. "steerability") at diameters selected based on needle payload requirements. We propose helical dovetail laser patterning to increase needle steerability without reducing shaft diameter. Experiments in phantoms and ex vivo animal muscle, brain, liver, and inflated lung tissues demonstrate high steerability in soft tissues. These experiments use needle diameters suitable for various clinical scenarios, and which have been previously limited by steering challenges without helical dovetail patterning. We show that steerable needle targeting remains accurate with established controllers and demonstrate interventional payload delivery (brachytherapy seeds and radiofrequency ablation) through the needle. Helical dovetail patterning decouples steerability from diameter in needle design. It enables diameter to be selected based on clinical requirements rather than being carefully tuned to tissue properties. These results pave the way for new sensors and interventional tools to be integrated into high-curvature steerable needles.

Cognitive Load in Electromagnetic Navigational and Robotic Bronchoscopy for Pulmonary Nodules.

Background: Electromagnetic navigational bronchoscopy (ENB) and robotic-assisted bronchoscopy (RB) require a high degree of decision-making and psychomotor skill. Cognitive load theory is the overall effort expended by individuals in response to a task and is closely related to the usability of devices for medical procedures. High cognitive workload leads to poor surgical outcomes and represents a bottleneck for learning that affects performance.Objective: To analyze the cognitive load associated with ENB and RB in experienced ENB practitioners learning RB.Methods: Six experienced ENB bronchoscopists performed ENB and RB on a human cadaver model of peripheral pulmonary nodules. To assess cognitive load, we used the Surgery Task Load Index (SURG-TLX) and biometric changes. The SURG-TLX questionnaire was given to the provider after every peripheral pulmonary nodule biopsy with ENB and RB. Pupillary dilation and screen changes were continuously measured throughout the procedure for each biopsy attempt to collect biometric measures of cognitive load. Procedural time and biopsy outcome were also recorded.Results: Forty procedures (ENB and RB) were analyzed. Task complexity (23%) and mental demand (21.4%) were the highest contributors to cognitive load in ENB and RB. The cumulative SURG-TLX was significantly lower for the RB (69.25 vs. 101.25; P < 0.01). Total procedure time was greater for ENB (6.7 min; SD 1.5) compared with RB (4.4 min; SD 1.5; P = 0.01). Pupillary diameter was similar across the modalities (RB vs. ENB), but the diameter was higher during the biopsy portion (4.25 mm) than the navigation portion (4.01 mm).Conclusion: The intrinsic cognitive load of RB was highly manageable by existing ENB practitioners, and in this study, RB appeared to be less mentally demanding. Future development and training should focus on task complexity and mental demand for RB. The biopsy portion, regardless of bronchoscopic modality, should be a focus for education and training.