The Feasibility of Using the "Artery Sign" for Pre-Procedural Planning in Navigational Bronchoscopy for Parenchymal Pulmonary Lesion Sampling.

BACKGROUND: Electromagnetic navigation bronchoscopy (ENB) and robotic-assisted bronchoscopy (RAB) systems are used for pulmonary lesion sampling, and utilize a pre-procedural CT scan where an airway, or "bronchus sign", is used to map a pathway to the target lesion. However, up to 40% of pre-procedural CT's lack a "bronchus sign" partially due to surrounding emphysema or limitation in CT resolution. Recognizing that the branches of the pulmonary artery, lymphatics, and airways are often present together as the bronchovascular bundle, we postulate that a branch of the pulmonary artery ("artery sign") could be used for pathway mapping during navigation bronchoscopy when a "bronchus sign" is absent. Herein we describe the navigation success and safety of using the "artery sign" to create a pathway for pulmonary lesion sampling. METHODS: We reviewed data on consecutive cases in which the "artery sign" was used for pre-procedural planning for conventional ENB (superDimension™, Medtronic) and RAB (Monarch™, Johnson & Johnson). Patients who underwent these procedures from July 2020 until July 2021 at the University of Minnesota Medical Center and from June 2018 until December 2019 at the University of Chicago Medical Center were included in this analysis (IRB #19-0011 for the University of Chicago and IRB #00013135 for the University of Minnesota). The primary outcome was navigation success, defined as successfully maneuvering the bronchoscope to the target lesion based on feedback from the navigation system. Secondary outcomes included navigation success based on radial EBUS imaging, pneumothorax, and bleeding rates. RESULTS: A total of 30 patients were enrolled in this analysis. The median diameter of the lesions was 17 mm. The median distance of the lesion from the pleura was 5 mm. Eleven lesions were solid, 15 were pure ground glass, and 4 were mixed. All cases were planned successfully using the "artery sign" on either the superDimension™ ENB (n = 15) or the Monarch™ RAB (n = 15). Navigation to the target was successful for 29 lesions (96.7%) based on feedback from the navigation system (virtual target). Radial EBUS image was acquired in 27 cases (90%) [eccentric view in 13 (43.33%) and concentric view in 14 patients (46.66%)], while in 3 cases (10%) no r-EBUS view was obtained. Pneumothorax occurred in one case (3%). Significant airway bleeding was reported in one case (3%). CONCLUSIONS: We describe the concept of using the "artery sign" as an alternative for planning EMN and RAB procedures when "bronchus sign" is absent. The navigation success based on virtual target or r-EBUS imaging is high and safety of sampling of such lesions compares favorably with prior reports. Prospective studies are needed to assess the impact of the "artery sign" on diagnostic yield.

Utility of Functional Pneumonectomy by Using Intrabronchial Valves: First Case Series and Single Center Experience.

BACKGROUND: Intrabronchial valves are approved for bronchoscopic lung volume reduction in chronic obstructive pulmonary disease patients and used for prolonged air leak. There is no data on bronchoscopic functional pneumonectomy (BFP) when treating patients with persistent air leak (PAL) or for lung volume reduction purposes. METHODS: In this observational study, 10 consecutive patients who failed to improve with traditional therapies were assessed after they underwent BFP for PAL or lung volume reduction. RESULTS: Ten patients underwent 17 valve placement procedures; 82 valves were placed (median: 8; range: 5 to 12). BFP was performed in 1 single lung transplant patient with hyperinflation of native lung compromising lung function. The rest of the patients had prolonged air leak because of various reasons; spontaneous (n=7) and postoperative (n=2). Pneumonia was the only procedure-related complication seen in 1 patient. Of patients with prolonged air leak with chest tubes (n=9), all had successful chest tube removal (median of 7 days; range: 3 to 21 d). The valves were removed within 6 weeks of chest tube removal in 6 patients. Prebronchoscopic and post-BFP actual forced expiratory volume in first second values in 2 transplant patients. CONCLUSION: PAL usually occurs in patients with severe underlying lung condition or after surgery. Management of PAL can be challenging despite pleurodesis (medical or surgical). BFP offers a minimally invasive management option.

To Investigate the Effect of Targeted Overdilation in Balloon-Expandable Stents.

PURPOSE: Balloon-expandable stents are commonly used for the treatment of tracheobronchial strictures. We routinely perform targeted overdilation of these stents 1-2mm on initial deployment to prevent stent migration or allow foreshortening to target airway caliber; however, specific data on the effect of targeted overdilation is unknown. PATIENTS AND METHODS: We used three iCAST stents (6×22mm, 7×22mm, and 10×38mm) to perform the study. We had two sets of each size to average our results. Targeted overdilation was accomplished with Merit Elation balloons. RESULTS: The 6 × 22 and 7 × 22 stent OD increased from 6 to 11.4mm and 7 to 11.6mm. The 10 × 38 stent demonstrated minimal OD change with overdilation (OD change of 10.4 to 12.2mm). All stents demonstrated significant foreshortening with overdilation (20.2 to 5.65mm, 19.4 to 6mm, and 30.9 to 10.2mm for 6 × 22, 7 × 22, and 10 × 38, respectively). The breakpoint was seen at near twice the stated stent OD (13.5mm, 15mm, and 15mm with 6 × 22, 7 × 22 and 10 × 38, respectively). CONCLUSION: We have demonstrated that iCAST stents can increase their OD with subsequent foreshortening during targeted overdilation. This data can help facilitate decisions when selecting a particular iCAST stent for a specific airway application. Additionally, we have highlighted that balloon inflation diameter does not correspond to the actual stent OD during deployment. We believe that this data offers practical information for end-users of this stent type and additional data will be needed to corroborate our findings.

ERCP-associated infected intrahepatic pancreatic pseudocyst.

INTRODUCTION: Pancreatic pseudocysts are abnormal mature collections of pancreatic fluid that can develop in association with acute or chronic pancreatitis. Here, we share the discovery of an infected hepatic subcapsular pseudocyst of the pancreas causing septic shock following endoscopic retrograde cholangiopancreatography (ERCP). PRESENTATION OF CASE: A 55-year-old woman with ethanol-related chronic pancreatitis and biliary stricture was transferred to the ICU for hypotension 8 hours following ERCP. Examination revealed mild right upper quadrant tenderness without sign of peritonitis. Laboratory studies were notable for leukocytosis (14.6 k/L) and slightly elevated serum lipase (489 U/L). Abdominal CT scan revealed a previously undescribed subcapsular fluid collection. She underwent CT-guided percutaneous subcapsular drainage with return of opaque yellowish fluid. Fluid analysis showed elevated lipase of 62,901 U/L with cultures positive for ESBL Escherichia coli, Streptococcus constellatus, and Enterococcus faecium. DISCUSSION: A majority of pancreatic pseudocysts develop in peripancreatic regions, while, in a recent study, over a quarter of cases were found in usual sites. The management of subcapsular pseudocysts has not been standardized and often involves endoscopic or percutaneous drainage. Operative intervention is reserved for severe infection or rupture in patients with intrahepatic pseudocysts. Rarely do subcapsular pseudocysts become infected. In this case, we postulate the pseudocyst became seeded by bacteria during ERCP resulting in infection and then sepsis. CONCLUSION: This case report highlights an atypical presentation of pancreatic pseudocyst as well as a rare septic complication of ERCP.

PEEP titration: the effect of prone position and abdominal pressure in an ARDS model.

BACKGROUND: Prone position and PEEP can both improve oxygenation and other parameters, but their interaction has not been fully described. Limited data directly compare selection of mechanically "optimal" or "best" PEEP in both supine and prone positions, either with or without changes in chest wall compliance. To compare best PEEP in these varied conditions, we used an experimental ARDS model to compare the mechanical, gas exchange, and hemodynamic response to PEEP titration in supine and prone position with varied abdominal pressure. METHODS: Twelve adult swine underwent pulmonary saline lavage and injurious ventilation to simulate ARDS. We used a reversible model of intra-abdominal hypertension to alter chest wall compliance. Response to PEEP levels of 20,17,14,11, 8, and 5 cmH2O was evaluated under four conditions: supine, high abdominal pressure; prone, high abdominal pressure; supine, low abdominal pressure; and prone, low abdominal pressure. Using lung compliance determined with esophageal pressure, we recorded the "best PEEP" and its corresponding target value. Data were evaluated for relationships among abdominal pressure, PEEP, and position using three-way analysis of variance and a linear mixed model with Tukey adjustment. RESULTS: Prone position and PEEP independently improved lung compliance (P < .0001). There was no interaction. As expected, intra-abdominal hypertension increased the PEEP needed for the best lung compliance (P < .0001 supine, P = .007 prone). However, best PEEP was not significantly different between prone (12.8 ± 2.4 cmH2O) and supine (11.0 ± 4.2 cmH2O) positions when targeting lung compliance CONCLUSIONS: Despite complementary mechanisms, prone position and appropriate PEEP exert their positive effects on lung mechanics independently of each other.

The Effect of Compartmental Asymmetry on the Monitoring of Pulmonary Mechanics and Lung Volumes.

BACKGROUND: Esophageal pressure measurement for computation of transpulmonary pressure (Ptp) has begun to be incorporated into clinical use for evaluating forces across the lungs. Gaps exist in our understanding of how esophageal pressure (and therefore Ptp), a value measured at a single site, responds when respiratory system compartments are asymmetrically affected by whole-lung atelectasis or unilateral injury as well as changes in chest wall compliance. We reasoned that Ptp would track with aerated volume changes as estimated by functional residual capacity (FRC) and tidal volume. We examined this hypothesis in the setting of asymmetric lungs and changes in intra-abdominal pressure. METHODS: This study was conducted in the animal laboratory of a university-affiliated hospital. Models of unilateral atelectasis and unilateral and bilateral lung injury exposed to intra-abdominal hypertension (IAH) in 10 deeply sedated mechanically ventilated swine. Atelectasis was created by balloon occlusion of the left main bronchus. Unilateral lung injury was induced by saline lavage of isolated right lung. Diffuse lung injury was induced by saline lavage of both lungs. The peritoneum was insufflated with air to create a model of pressure-regulated IAH. We measured esophageal pressures, airway pressures, FRC by gas dilution, and oxygenation. RESULTS: FRC was reduced by IAH in normal lungs (P < .001) and both asymmetric lung pathologies (P < .001). Ptp at end-expiration was decreased by IAH in bilateral (P = .001) and unilateral lung injury (P = .003) as well as unilateral atelectasis (P = .019). In the setting of both lung injury models, end-expiratory Ptp showed a moderate correlation in tracking with FRC. CONCLUSIONS: Ptp tracks with aerated lung volume in the setting of thoracic asymmetry and changes in intra-abdominal pressure. However, used alone, it cannot distinguish the relative contributions of air-space distention and recruitment of lung units.

Parasomnia Overlap Disorder with Sexual Behaviors during Sleep in a Patient with Obstructive Sleep Apnea.

ABSTRACT: Sleep-related abnormal sexual behaviors (sexsomnia) are classified as a subtype of NREM sleep parasomnias. Sexsomnia has been reported as part of parasomnia overlap disorder (POD) in two other patients. We present the case of a 42-year-old male patient with video-polysomnography (vPSG) documented POD. The patient had sleepwalking, sleep-related eating, confusional arousals, sexsomnia, sleeptalking, and REM sleep behavior disorder (RBD). Confusional arousals and RBD were documented during the vPSG. This case had the added complexity of obstructive sleep apnea (OSA) playing a role in sleepwalking and sleep related eating, with good response to nasal continuous positive airway pressure (nCPAP). The sexsomnia did not respond to nCPAP but responded substantially to bedtime clonazepam therapy.

IgG4-related lung disease: a case series of 6 patients and review of the literature.

IgG4 related disease has been recently proposed as a unifying term for a group of inflammatory conditions previously referred to by a plethora of other names. The common denominator for these entities is the histopathologic finding of lymphocytic infiltrates rich in IgG4 producing plasma cells, often accompanied by storiform fibrosis and obliterative phlebitis. Many medical conditions have been attributed to IgG4-related disease,but few reports of IgG4-related lung disease have been published, and it remains a rare condition about which little is known. In this report, we describe the clinical and pathologic features of six patients with IgG4-related disease of the lung. Patients were followed 1-5 years following their diagnosis. We describe unique features of IgG4-related lung disease, including one patient who presented with alveolar hemorrhage and a positive anti-neutrophil cytoplasmic antibody and two patients whose disease improved after treatment with mycophenylate mofetil. Two patients presented with pulmonary pseudotumor. We conclude that the clinical presentation of IgG4-related lung disease varies widely, and histopathology remains the key to diagnosis.

Impact of Chest Wall Modifications and Lung Injury on the Correspondence Between Airway and Transpulmonary Driving Pressures.

OBJECTIVE: Recent interest has arisen in airway driving pressure (DP(AW)), the quotient of tidal volume (V(T)), and respiratory system compliance (C(RS)), which could serve as a direct and easily measured marker for ventilator-induced lung injury risk. We aimed to test the correspondence between DP(AW) and transpulmonary driving pressure (DP(TP))-the quotient of V(T) and lung compliance (C(L)), in response to intra-abdominal hypertension and changes in positive end-expiratory pressure during different models of lung pathology. DESIGN: Well-controlled experimental setting that allowed reversible modification of chest wall compliance (C(CW)) in a variety of models of lung pathology. SETTING: Large animal laboratory of a university-affiliated hospital. SUBJECTS: Ten deeply anesthetized swine. INTERVENTIONS: Application of intra-abdominal pressures of 0 and 20 cm H2O at positive end-expiratory pressure of 1 and 10 cm H2O, under volume-controlled mechanical ventilation in the settings of normal lungs (baseline), unilateral whole-lung atelectasis, and unilateral and bilateral lung injuries caused by saline lavage. MEASUREMENTS AND MAIN RESULTS: Pulmonary mechanics including esophageal pressure and calculations of DP(AW), DP(TP), C(RS), C(L), and C(CW). When compared with normal intra-abdominal pressures, intra-abdominal hypertension increased DP(AW), during both "normal lung conditions" (p < 0.0001) and "unilateral atelectasis" (p = 0.0026). In contrast, DP(TP) remained virtually unaffected by changes in positive end-expiratory pressure or intra-abdominal pressures in both conditions. During unilateral lung injury, both DPA(W) and DP(TP) were increased by the presence of intra-abdominal hypertension (p < 0.0001 and p = 0.0222, respectively). During bilateral lung injury, intra-abdominal hypertension increased both DP(AW) (at positive end-expiratory pressure of 1 cm H2O, p < 0.0001; and at positive end-expiratory pressure of 10 cm H2O, p = 0.0091) and DP(TP) (at positive end-expiratory pressure of 1 cm H2O, p = 0.0510; and at positive end-expiratory pressure of 10 cm H2O, p = 0.0335). CONCLUSIONS: Our data indicate that DP(AW) is influenced by reductions in chest wall compliance and by underlying lung properties. As with other measures of pulmonary mechanics that are based on unmodified P(AW), caution is advised in attempting to attribute hazard or safety to any specific absolute value of DP(AW).

Management of the bleeding patient receiving new oral anticoagulants: a role for prothrombin complex concentrates.

Ease of dosing and simplicity of monitoring make new oral anticoagulants an attractive therapy in a growing range of clinical conditions. However, newer oral anticoagulants interact with the coagulation cascade in different ways than traditional warfarin therapy. Replacement of clotting factors will not reverse the effects of dabigatran, rivaroxaban, or apixaban. Currently, antidotes for these drugs are not widely available. Fortunately, withholding the anticoagulant and dialysis are freqnently effective treatments, particularly with rivaroxaban and dabigatran. Emergent bleeding, however, requires utilization of Prothrombin Complex Concentrates (PCCs). PCCs, in addition to recombinant factor VIIa, are used to activate the clotting system to reverse the effects of the new oral anticoagulants. In cases of refractory or emergent bleeding, the recommended factor concentrate in our protocols differs between the new oral anticoagulants. In patients taking dabigatran, we administer an activated PCC (aPCC) [FELBA] due to reported benefit in human in vitro studies. Based on human clinical trial evidence, the 4-factor PCC (Kcentra) is suggested for patients with refractory rivaroxaban- or apixaban-associated hemorrhage. If bleeding continues, recombinant factor VIIa may be employed. With all of these new procoagulant agents, the risk of thrombosis associated with administration of factor concentrates must be weighed against the relative risk of hemorrhage.

Unilateral mechanical asymmetry: positional effects on lung volumes and transpulmonary pressure.

BACKGROUND: Ventilated patients with asymmetry of lung or chest wall mechanics may be vulnerable to differing lung stresses or strains dependent on body position. Our purpose was to examine transpulmonary pressure (P TP) and end-expiratory lung volume (functional residual capacity (FRC)) during body positioning changes in an animal model under the influence of positive end-expiratory pressure (PEEP) or experimental pleural effusion (PLEF). METHODS: Fourteen deeply anesthetized swine were studied including tracheostomy, thoracostomy, and esophageal catheter placement. Animals were ventilated at V T = 10 ml/kg, frequency of 15, I/E = 1:2, and FIO2 = 0.5. The animals were randomized to supine, prone, right lateral, left lateral, and semi-Fowler positions with a PEEP of 1 cm H2O (PEEP1) or a PEEP of 10 cm H2O (PEEP10) applied. Experimental PLEF was generated by 10 ml/kg saline instilled into either pleural space. P TP and FRC were determined in each condition. RESULTS: No significant differences in FRC were found among the four horizontal positions. Compared to horizontal positioning, semi-Fowler's increased FRC (p < 0.001) by 56% at PEEP1 and 54% at PEEP10 without PLEF and by 131% at PEEP1 and 98% at PEEP10 with PLEF. Inspiratory or expiratory P TP showed insignificant differences across positions at both levels of PEEP. Consistently negative end-expiratory P TP at PEEP1 increased to positive values with PEEP10. CONCLUSIONS: FRC did not differ among horizontal positions; however, semi-Fowler's positioning significantly raised FRC. P TP proved insensitive to mechanical asymmetry. While end-expiratory P TP was negative at PEEP1, applying PEEP10 caused a transition to positive P TP, suggestive of reopening of initially compressed lung units.

Lung recruitment in acute respiratory distress syndrome: what is the best strategy?

PURPOSE OF REVIEW: Supporting patients with acute respiratory distress syndrome (ARDS) using a low tidal volume strategy is a standard practice in the ICU. Recruitment maneuvers can be used to augment other methods, like positive end-expiratory pressure and positioning, to improve aerated lung volume. Clinical practice varies widely, and optimal method and patient selection for recruitment maneuvers have not been determined. RECENT FINDINGS: Recent developments include experimental and clinical evidence that a stepwise extended recruitment maneuver may match the improvement in aerated lung volume seen with sustained inflation traditionally used, with less adverse effects. Positioning and other chest wall modifications may be useful adjuncts to recruitment maneuvers. In addition, evidence from clinical studies in the operating room suggests that recruitment maneuvers, as a component of an open lung strategy, may be helpful for mechanically ventilated patients with normal lungs. SUMMARY: As a component of ventilation strategy for patients with ARDS, the use of recruitment maneuvers, especially a stepwise maneuver, in addition to adequate positive end-expiratory pressure and appropriate positioning, is suggested by currently available data. Until their effect on clinical outcomes is further defined, the use of recruitment maneuvers in ARDS and other settings will continue to be guided by individual clinician experience and patient factors.