Comparison of BlockBuster laryngeal mask with Air-Q intubating laryngeal airway as a conduit for fiber-optic guided intubation in children: A prospective randomized controlled study.

BACKGROUND: The pediatric sizes of BlockBuster supraglottic airway (SGA) have been introduced recently. Its efficacy as a conduit for endotracheal intubation in children has not been assessed. Newer devices are often compared with Air-Q SGA to assess their intubating capability. AIMS: The primary objective was to compare the time taken for fiber-optic-guided intubation through the BlockBuster and the Air-Q SGAs. METHODS: Sixty children aged 6 months to 12 years with normal airways were randomized into two groups: Air-Q SGA (Group A) and Blockbuster SGA (Group B). After administration of general anesthesia, an appropriately sized SGA was inserted. The time taken for fiber-optic-guided intubation through the SGA, success, ease, and time for SGA insertion and removal were noted. The glottic view was graded by fiber-optic bronchoscopy. RESULTS: Demographic parameters were comparable. The time to intubate with the BlockBuster 62.40 ± 17.2 s was comparable to the Air-Q 60.8 ± 18.5 s (mean difference 1.6 s, 95% CI -7.65 to10.85; p = .73). The average time for SGA insertion in BlockBuster and Air-Q was 14.57 ± 3.2 s and 16.67 ± 5.39 s, respectively (mean difference -2.1, 95% CI -4.39 to 0.19 s; p = .07). The first-attempt intubation success and overall intubation success rates were comparable in both groups, 96.7% and 100%, respectively. In Group B, 25/3/1/1/0 cases had a glottic view grade of 1/2/3/4/5, respectively. In Group A, 23/3/2/2/0 cases had grade of 1/2/3/4/5 glottic views respectively. The average time to SGA removal was comparable between the BlockBuster (20.17 ± 5.8 s) and the Air-Q (22.5 ± 12.8 s) groups (mean difference -2.3 s, 95% CI -7.5 to 2.82 s; p = .37). None of the children had any perioperative complications. CONCLUSION: BlockBuster SGA may be a useful alternative to Air-Q for SGA-assisted, fiber-optic-guided tracheal intubation in children.

Ultrasound guided costoclavicular block in pediatric population: A prospective observational study.

BACKGROUND: The costoclavicular space serves as an alternative approach to the infraclavicular brachial plexus block, and numerous studies in adults have demonstrated promising outcomes for distal upper limb surgery. Blocking the brachial plexus at this level is potentially advantageous because the cords are relatively superficial, located in close proximity to each other and easily identified using ultrasound. AIMS: This study aimed to assess the success rate and feasibility of costoclavicular block in children undergoing unilateral below elbow upper limb surgery. METHODS: Thirty children aged 2-12 years scheduled for unilateral below elbow surgery under general anesthesia were included. Costoclavicular block was performed under ultrasound and nerve stimulator guidance with 0.5% ropivacaine, 0.5 mL/kg. Success was evaluated based on the absence of significant hemodynamic response to skin incision made 20 min after the block. The sono-anatomy of costoclavicular space, ease of needling, complications, and the post-operative pain scores were assessed. RESULTS: The mean age and weight of the children were 6.5 ± 3.8 years and 19.7 ± 9.1 kg, respectively. The success rate of costoclavicular block in our cohort is 100%. Sonographic visualization was graded as excellent (Likert Scale 2) in 90% of cases. The plexus was located at a depth of 1.4 ± 0.3 cm from the skin, the lateral extent of cords from the artery was 0.8 ± 0.4 cm and they were observed inferior and lateral to the artery. The mean needling time was 3.6 ± 1.1 min. None of the children experienced complications such as vascular or pleural puncture, hematoma, Horner's syndrome or diaphragmatic palsy. Postoperative pain scores were low, and no rescue analgesia was required. CONCLUSIONS: In conclusion, the costoclavicular block exhibited a notably high success rate in pediatric population. This study substantiates that the three cords of the brachial plexus are consistently visible and superficial during ultrasound examination using this approach, confirming their separation from vascular structures and the reliable achievement of blockade without observed complications.

Understanding Options for the Unmatched Urology Applicant.

PURPOSE OF REVIEW: To evaluate recent literature regarding the pathways and options for unmatched urology applicants. RECENT FINDINGS: Urology remains a competitive surgical sub-specialty with a match process independent of the National Resident Matching Program. Each year a cohort of competitive applicants go unmatched and are faced with the decision to reapply the following cycle while doing a research fellowship or a preliminary internship in the interim or choose a different specialty altogether. In this review, we sought to evaluate the current match process and literature regarding outcomes and options for unmatched applicants as well as to provide future directions for research and improvements to support unmatched urology applicants. Presently, data regarding outcomes for unmatched applicants is relatively limited. Going forward it is imperative for national urology organizations to create centralized resources for applicants to provide the best possible information for applicants and mentors alike.

Comparison of Ambu AuraGain and BlockBuster laryngeal mask for controlled ventilation in children undergoing minor surgical procedures under general anesthesia: A prospective randomized controlled study.

BACKGROUND: Ambu AuraGain has proven to be better compared with other supraglottic airway devices in terms of higher first-attempt insertion success rate, time and ease of insertion, high oropharyngeal leak pressure, and fewer complications in children. The performance of the BlockBuster laryngeal mask has not been evaluated in children. AIMS: The primary objective of this study was to compare the oropharyngeal leak pressure of the BlockBuster laryngeal mask with those of the Ambu AuraGain during controlled ventilation in children. METHODS: Fifty children aged 6 months to 12 years with normal airways were randomized into group A (Ambu AuraGain) and group B (BlockBuster laryngeal mask). After administration of general anesthesia, an appropriate size supraglottic airway (size 1.5/2.0/2.5) was inserted according to the groups. Oropharyngeal leak pressure, success and ease of supraglottic airway insertion, gastric tube insertion, and ventilatory parameters were noted. The glottic view was graded by fiberoptic bronchoscopy. RESULTS: Demographic parameters were comparable. The mean oropharyngeal leak pressure in the BlockBuster group (24.72 ± 6.81 cm H2 O) was significantly higher than Ambu AuraGain group (17.20 ± 4.28 cm H2 O) by 7.52 cm H2 O (95% CI 4.27 to 10.76; p = 0.001). The mean time for supraglottic airway insertion in the BlockBuster and Ambu AuraGain group was 12.04 ± 2.55 s and 13.64 ± 2.76 s, respectively (mean difference- 1.6 s, 95% CI 0.09-3.12; p = 0.04). Ventilatory parameters, first-attempt supraglottic airway insertion success rate, and ease of gastric tube insertion were comparable between the groups. The BlockBuster group showed easy supraglottic airway insertion compared with the Ambu AuraGain group. The BlockBuster group had better glottic views with only the larynx seen in 23 out of 25 children compared to the Ambu AuraGain with only the larynx seen in 19 out of 25 children. No complication was noted in either group. CONCLUSIONS: We found that the BlockBuster laryngeal mask has higher oropharyngeal leak pressure compared with Ambu AuraGain in a pediatric population.

In-person radiologist to review the trauma panscan: a high-fidelity simulation training program for radiology trainees at an academic level 1 trauma center.

BACKGROUND: Radiology trainees were uncomfortable going to the CT scanner to review trauma panscans and interacting with trauma surgeons. OBJECTIVE: This study aims to determine if radiology residents can be trained to accurately identify injuries requiring immediate surgical attention at the CT scanner. METHODS: A high-fidelity simulation model was created to provide an immersive training experience. Between February 2015 and April 2017, 62 class 1 trauma panscans were read at the CT scanner by 11 PGY-3 radiology residents. Findings made at the scanner were compared to resident preliminary and attending radiology reports and correlated with clinical outcomes. Timestamps were recorded and analyzed. Surveys were administered to assess the impact of training on radiology residents' self-confidence and to assess trauma surgeons' preference for radiology at the scanner. Significance level was set at p < 0.05. RESULTS: The mean time to provide results at the CT scanner was 11.1 min. Mean time for the preliminary report for CT head and cervical spine was 24.4 ± 9.8 min, and for the CT chest, abdomen, and pelvis was 16.3 ± 6.9 min. 53 traumatic findings on 62 panscans were identified at the scanner and confirmed at preliminary and final reports, for a concordance rate of 85%, compared to 72% for the control group. Radiology residents agreed or strongly agreed the training prepared them for trauma panscan reporting. Trauma surgeons shifted in favor of radiology presence at the scanner. CONCLUSION: Radiology residents can be trained to accurately and rapidly identify injuries requiring immediate surgical attention at the CT scanner. CLINICAL IMPACT: These findings support the value-added of an in-person radiologist at the CT scanner for whole-body trauma panscans to facilitate timely detection of life-threatening injuries and improve professional relations between radiologists and trauma surgeons.

Endoscopic Pancreatic Function Testing (ePFT) in Children: A Position Paper From the NASPGHAN Pancreas Committee.

ABSTRACT: Endoscopic pancreatic function testing (ePFT) is one of the few ways to directly diagnose exocrine pancreatic insufficiency, and considerable confusion regarding indications, utility, and interpretation of the test remains. This position paper of the Pancreas Committee of the North American Society of Pediatric Gastroenterology, Hepatology and Nutrition reviews the history and indications for ePFT in children. We compare various methods in current practice and determine their strengths and limitations, and based on data from children and adults we provide guidance on a protocol on how to perform ePFT in children. Lastly, we pose areas in need of further research relating to ePFT in children.

Neutrophil-to-lymphocyte Ratio and Platelet-to-lymphocyte Ratio as Markers for Predicting the Severity in COVID-19 Patients: A Prospective Observational Study.

Background: Coronavirus disease-2019 (COVID-19) pandemic has shown unpredictable course in individual patients. Few patients develop severe disease with progression after admission to a healthcare facility. Multiple parameters have been investigated to identify a marker to predict disease progression. Neutrophil-to-lymphocyte ratio (NLR) or platelet-to-lymphocyte (PLR) ratio has shown some promise. The current investigation explores the role of NLR and PLR to predict the disease progression. Materials and methods: After obtaining ethics committee approval, 608 patients were screened for inclusion in the prospective observational study, and 201 patients were included in the final analysis. The NLR and PLR were derived from routinely obtained complete blood count analysis. The patients were followed to determine the development of severity of the disease during the course. The NLR and PLR were analyzed in both univariate and multivariable models to assess the association and prediction. Results: In nonsevere (NS) group, the mean age of patients was 50.9 ± 16.3 years, and 66 (61.2%) were male, while in severe group (S), the mean age of patients was 53.7 ± 16.4 years, and 65 (69.89%) were male. NLR at day 1 and day 3 was significantly lower in survivors as compared to nonsurvivors, while the relation of PLR in both the groups was not statistically significant. The NLR is better in predicting the severity of disease as well as mortality than PLR. Conclusion: The NLR calculated at the time of admission has high predictive value for disease deterioration and adverse clinical outcome. How to cite this article: Singh Y, Singh A, Rudravaram S, Soni KD, Aggarwal R, Patel N, et al. Neutrophil-to-lymphocyte Ratio and Platelet-to-lymphocyte Ratio as Markers for Predicting the Severity in COVID-19 Patients: A Prospective Observational Study. Indian J Crit Care Med 2021;25(8):847-852.

Clinical Course and Outcome of Critically Ill Obese Patients with COVID-19 Admitted in Intensive Care Unit of a Single Center: Our Experience and Review.

INTRODUCTION: Obesity has been considered as one of the independent risk factors for a severe form of coronavirus disease-2019 (COVID-19) and relationship between obesity, critical illness, and infection is still poorly understood. We herein discuss clinical course and outcome of critically ill obese patients with COVID-19 admitted to critical care unit. MATERIALS AND METHODS: We retrospectively analyzed data of critically ill obese patients hospitalized with COVID-19 over a span of 6 months. Management was guided according to the institutional protocol. Collected data included demographic parameters (age, sex, comorbidities, and body mass index (BMI)), complications, inflammatory markers (interleukin (IL)-6, Ferritin), length of mechanical ventilation, length of intensive care unit (ICU) stay, and inhospital death. RESULTS: There was no appreciable difference in terms of demographics, inflammatory markers, predictors of mortality scores, and comorbidity indices between the survivors and nonsurvivors. Among outcome analysis, there was a statistically significant difference between ventilator days between survivors and nonsurvivors (p = 0.003**). CONCLUSION: Obesity itself is a significant risk factor for severe COVID-19 infection; however, if efficiently managed and in a protocol-determined manner, it can have a favorable outcome. HOW TO CITE THIS ARTICLE: Kaur M, Aggarwal R, Ganesh V, Kumar R, Patel N, Ayub A, et al. Clinical Course and Outcome of Critically Ill Obese Patients with COVID-19 Admitted in Intensive Care Unit of a Single Center: Our Experience and Review. Indian J Crit Care Med 2021;25(12):1382-1386.

Clinicoepidemiological Features and Mortality Analysis of Deceased Patients with COVID-19 in a Tertiary Care Center.

BACKGROUND AND OBJECTIVE: A large number of studies describing the clinicoepidemiological features of coronavirus disease-2019 (COVID-19) patients are available but very few studies have documented similar features of the deceased. This study was aimed to describe the clinicoepidemiological features and the causes of mortality of COVID-19 deceased patients admitted in a dedicated COVID center in India. METHODOLOGY: This was a retrospective study done in adult deceased patients admitted in COVID ICU from April 4 to July 24, 2020. The clinical features, comorbidities, complications, and causes of mortality in these patients were analyzed. Pediatric deceased were analyzed separately. RESULTS: A total of 654 adult patients were admitted in the ICU during the study period and ICU mortality was 37.7% (247/654). Among the adult deceased, 65.9% were males with a median age of 56 years [interquartile range (IQR), 41.5-65] and 94.74% had one or more comorbidities, most common being hypertension (43.3%), diabetes mellitus (34.8%), and chronic kidney disease (20.6%). The most common presenting features in these deceased were fever (75.7%), cough (68.8%), and shortness of breath (67.6%). The mean initial sequential organ failure assessment score was 9.3 ± 4.7 and 24.2% were already intubated at the time of admission. The median duration of hospital stay was 6 days (IQR, 3-11). The most common cause of death was sepsis with multi-organ failure (55.1%) followed by severe acute respiratory distress syndrome (ARDS) (25.5%). All pediatric deceased had comorbid conditions and the most common cause of death in this group was severe ARDS. CONCLUSION: In this cohort of adult deceased, most were young males with age less than 65 years with one or more comorbidities, hypertension being the most common. Only 5% of the deceased had no comorbidities. Sepsis with multi-organ dysfunction syndrome was the most common cause of death. HOW TO CITE THIS ARTICLE: Aggarwal R, Bhatia R, Kulshrestha K, Soni KD, Viswanath R, Singh AK, et al. Clinicoepidemiological Features and Mortality Analysis of Deceased Patients with COVID-19 in a Tertiary Care Center. Indian J Crit Care Med 2021; 25(6):622-628.

The Roles of Endoscopic Ultrasound and Endoscopic Retrograde Cholangiopancreatography in the Evaluation and Treatment of Chronic Pancreatitis in Children: A Position Paper From the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition Pancreas Committee.

INTRODUCTION: Pediatric chronic pancreatitis is increasingly diagnosed. Endoscopic methods [endoscopic ultrasound (EUS), endoscopic retrograde cholangiopancreatography (ERCP)] are useful tools to diagnose and manage chronic pancreatitis. Pediatric knowledge and use of these modalities is limited and warrants dissemination. METHODS: Literature review of publications relating to use of ERCP and EUS for diagnosis and/or management of chronic pancreatitis with special attention to studies involving 0--18 years old subjects was conducted with summaries generated. Recommendations were developed and voted upon by authors. RESULTS: Both EUS and ERCP can be used even in small children to assist in diagnosis of chronic pancreatitis in cases where cross-sectional imaging is not sufficient to diagnose or characterize the disease. Children under 15 kg for EUS and 10 kg for ERCP can be technically challenging. These procedures should be done optimally by appropriately trained endoscopists and adult gastroenterology providers with appropriate experience treating children. EUS and ERCP-related risks both include perforation, bleeding and pancreatitis. EUS is the preferred diagnostic modality over ERCP because of lower complication rates overall. Both modalities can be used for management of chronic pancreatitis -related fluid collections. ERCP has successfully been used to manage pancreatic duct stones. CONCLUSION: EUS and ERCP can be safely used to diagnose chronic pancreatitis in pediatric patients and assist in management of chronic pancreatitis-related complications. Procedure-related risks are similar to those seen in adults, with EUS having a safer risk profile overall. The recent increase in pediatric-trained specialists will improve access of these modalities for children.

Cancer Immunotherapeutic Potential of NKTT320, a Novel, Invariant, Natural Killer T Cell-Activating, Humanized Monoclonal Antibody.

Invariant natural killer T cells (iNKTs) directly kill tumor cells and trans-activate the anti-tumor functions of dendritic cells (DC), natural killer (NK) cells, and T and B cells. As such, iNKTs serve as a powerful tool for use in cell-based cancer immunotherapy. iNKT cell activation commonly requires engagement of the invariant T cell receptor (iTCR) by CD1d presenting glycolipid antigens. However, transformed cells often down-regulate CD1d expression, which results in a reduction of iNKT cell anti-tumor functions. One approach to circumvent this critical barrier to iNKT cell activation is to develop an agonistic antibody that binds directly to the iTCR without the requirement for CD1d-mediated antigen presentation. To this end, we have characterized the iNKT cell stimulatory properties of NKTT320, a novel, recombinant, humanized, monoclonal antibody that binds selectively and with high affinity to human iTCRs. Strikingly, immobilized NKTT320 mediated robust iNKT cell activation (upregulation of CD25 and CD69) and proliferation (carboxyfluorescein succinimidyl ester (CFSE) dilution), as well as Th1 and Th2 cytokine production. Additionally, iNKTs stimulated by plate-bound NKTT320 exhibited increased intracellular levels of granzyme B and degranulation (exposure of CD107 on the cell surface). Furthermore, both soluble and immobilized NKTT320 induced iNKT cell-mediated activation of bystander immune cells, suggesting that this novel anti-iTCR antibody facilitates both direct and indirect iNKT cell cytotoxicity. These studies are significant, as they provide a framework by which iNKT cell anti-cancer functions could be enhanced for therapeutic purposes.

Endobronchial Forceps-Assisted Removal of Gianturco Z-Stents from the Right Atrium.

Endovascular treatment of malignant intrahepatic inferior vena cava stenosis involves venoplasty and stenting. Intravascular migration is a complication associated with stents. This technical report describes the retrieval of migrated intracardiac Gianturco Z-stents using rigid endobronchial forceps.

Endovascular Transpulmonary Retrieval of a Migrated Amplatzer Vascular Plug Following Balloon-Occluded Retrograde Transvenous Obliteration.

Gastric varices are a common manifestation of portal hypertension and are associated with a high rate of mortality and rebleeding. Balloon-occluded retrograde transvenous obliteration (BRTO) is a commonly used method to sclerose gastric varices and has a high clinical success. Common complications following BRTO include portal or splenic vein thrombosis, systemic sclerosant extravasation, pulmonary emboli, and inferior vena cava thrombosis. This report describes a patient with vascular plug migration into the left pulmonary artery with subsequent endovascular retrieval.

A Contemporary Analysis of Heart Transplantation and Bridge-to-Transplant Mechanical Circulatory Support Outcomes in Cardiac Sarcoidosis.

BACKGROUND: Patients with end-stage cardiomyopathy due to cardiac sarcoidosis (CS) may be referred for mechanical circulatory support (MCS) and heart transplantation (HT). We describe outcomes of patients with CS undergoing HT, focusing on the use of MCS as a bridge to transplant (BTT). METHODS: Using the United Network for Organ Sharing Scientific Registry of Transplant Recipients, we identified all adult waitlisted patients and isolated HT recipients from 2006 to 2015. These were divided into those with and without CS and further divided into those who did or did not receive MCS as BTT. Outcomes included 1- and 5-year post-transplantation freedom from mortality and 5-year freedom from primary graft failure. RESULTS: Over the study period, 31,528 patients were listed for HT, 148 (0.4%) of whom had CS. Among the CS patients, 34 (23%) received MCS as BTT. 18,348 patients (58%) eventually underwent HT, including 67 (0.4%) with CS, 20 (30%) of whom had received BTT MCS. Compared with non-CS diagnoses, CS patients had similar 1-year (91% vs 90%; log rank P = .88) and 5-year (83% vs 77%; log rank P = .46) freedom from mortality. Survival was also similar between CS BTT and non-CS BTT groups at 1 year (89% vs 89%; log-rank P = .92) and 5 years (72% vs 75%; log-rank P = .77). CONCLUSIONS: Survivals after HT were similar between CS and non-CS patients out to 5 years, and were also similar between CS and non-CS BTT cohorts. Both HT and BTT MCS should be considered in patients with CS.

Interventional Radiology-Operated Cholecystoscopy for the Management of Symptomatic Cholelithiasis: Approach, Technical Success, Safety, and Clinical Outcomes.

OBJECTIVE: The objective of our study was to report the technique, complications, and clinical outcomes of interventional radiology-operated cholecystoscopy with stone removal for the management of symptomatic cholelithiasis. MATERIALS AND METHODS: Ten (77%) men and three (23%) women (mean age, 65 years) with symptomatic cholelithiasis underwent cholecystostomy followed by interventional radiology-operated cholecystoscopy with stone removal. Major comorbidities precluding cholecystectomy included prior cardiac, pulmonary, or abdominal surgery; cirrhosis; sepsis with hyponatremia; seizure disorder; developmental delay; and cholecystoduodenal fistula. Cholecystostomy access, time between cholecystostomy and cholecystoscopy, endoscopic and fragmentation devices used, technical success, procedure time, fluoroscopy time, complications, length of hospital stay, time between cholecystoscopy and cholecystostomy removal, follow-up, and acute cholecystitis recurrence were recorded. RESULTS: Eleven (85%) patients underwent transhepatic cholecystostomy, and two (15%) patients underwent transperitoneal cholecystostomy. The mean time from cholecystostomy to cholecystoscopy was 151 days. Flexible endoscopy was used in eight (62%) patients, rigid endoscopy in three (23%), and both flexible and rigid in two (15%). Electrohydraulic lithotripsy was used in eight procedures, nitinol baskets in seven, ultrasonic lithotripsy in two, and percutaneous thrombectomy devices in one. Primary technical success was achieved in 11 (85%) patients, and secondary technical success was achieved in 13 (100%) patients. The mean procedure time was 164 minutes, and the mean number of procedures required to clear all gallstones was 1. One (8%) patient developed acute pancreatitis, and one (8%) patient died of gastrointestinal hemorrhage. The median hospital length of stay after cholecystoscopy was 1 day for postoperative monitoring. The mean time between cholecystoscopy and cholecystostomy removal was 39 days. One (8%) patient developed recurrent acute cholecystitis 1095 days after cholecystoscopy. CONCLUSION: Interventional radiology-operated cholecystoscopy may serve as an effective method for percutaneous gallstone removal in patients with multiple comorbidities precluding cholecystectomy.

#VascularSurgery.

BACKGROUND: To characterize the vascular surgery Twitter network. METHODS: A total of 20,841 consecutive tweets by 8,282 unique Twitter accounts regarding vascular surgery from October 23, 2014 to January 15, 2018 were analyzed. Twitter analytics, including activity metrics, content analysis, user characteristics, engagement, and network analysis were performed using Symplur Signals, a health care social media analytics platform. RESULTS: Vascular surgery tweets, the number of users tweeting about vascular surgery, and vascular surgery tweet impressions have increased by an annual average of 77.8%, 55.3%, and 209.1% from 2015 to 2017, respectively. Twitter activity trend analysis showed consistent growth over the study period with an average of 25.7 ± 2.6 additional tweets per month (P < 0.001). As for tweet content, 2,220 tweets (10.7%) were pertaining to patients, and 2,198 tweets (10.5%) were regarding new or innovative topics. 15,422 tweets (74.0%) included links to journals or websites and 6,826 tweets (32.8%) contained at least 1 image. Deep venous thrombosis, pulmonary embolism, diabetes, endovascular interventions, trauma, and practice guidelines were among the most commonly discussed health topics. Physicians composed 5,618 tweets (27%), while patients submitted 2,447 tweets (11.7%). As for engagement, 8,886 tweets (42.6%) were retweets, 11,816 tweets (56.7%) mentioned at least 1 other user, and 786 tweets (3.8%) were replies. Network analysis revealed central hubs to be vascular surgery societies, academic institutions, academic journals, and physicians. CONCLUSIONS: The use of Twitter to discuss vascular surgery is growing rapidly with increasing use by vascular surgeons and vascular medicine physicians. An effort to involve more patients in the vascular surgery Twitter social network may allow for more opportunities to educate, and garner interest and support for vascular surgery.

Ureteral access sheaths: a comprehensive comparison of physical and mechanical properties.

INTRODUCTION: Ureteral access sheaths (UAS) facilitate flexible ureteroscopy in the treatment of urolithiasis. The physical properties of UAS vary by manufacturer and model. We compared three new UAS: Glideway (GW, Terumo, 11/13Fr, 12/14Fr), Pathway (PW, Terumo 12/14F) and Navigator HD (NHD, Boston Scientific, 11/13Fr, 12/14Fr) in the domains of safety characteristics, positioning characteristics, lubricity and radioopacity. MATERIALS AND METHODS: In vitro testing of the three UAS included safety testing-tip perforation force, sheath edge deformation and dilator extraction forces. Positioning characteristics tested included tip bending, stiffness (resistance to coaxial buckling forces), kinking (resistance to perpendicular forces), and insertion forces. Lubricity was assessed by measured frictional forces of the outer sheath. Finally, radio-opacity was tested utilizing fluoroscopic imaging of the three 12F sheaths and inner dilators. RESULTS: The PW (0.245 lb) and GW (0.286 lb) required less force for tip perforation compared to the NHD (0.628 lb). The NHD sheath edge deformation was mild compared to more severe deformation for the PW and GW. The PW (1.008 lb) required greater force than the GW (0.136 lb) and NHD (0.043 lb) for inner dilator removal. The GW (3.69 lbs) and NHD (4.17 lb) had similar inner dilator tip stiffness when bent, while the PW had the weakest inner dilator tip, 1.91 lbs. The PW (0.271 lb) was most susceptible to buckling and kinking (1.626 lb). The most lubricious UAS was the NHD (0.055 lbs for 12F). The NHD (0.277 lbs) required the least insertional force through a biological model and possessed the greatest radio-opacity. CONCLUSIONS: Comparison of different commercially available UAS in various sizes reveals that there are mechanical differences in sheaths that may play a role clinically. The Terumo sheaths' (GW and PW) were outperformed by the Boston Scientific NHD in simulating safety, ease of use and radio-opacity.

Computerized Tomography Based Diagnosis of Visceral Obesity and Hepatic Steatosis is Associated with Low Urine pH.

PURPOSE: Uric acid nephrolithiasis is associated with an elevated visceral fat area in kidney stone formers. Hepatic steatosis has also been linked to visceral obesity and nephrolithiasis. We evaluated the association of noncontrast computerized tomography based diagnosis of visceral obesity and hepatic steatosis with 24-hour urine parameters and stone composition in kidney stone formers. MATERIALS AND METHODS: A total of 98 kidney stone formers were included in study who had computerized tomography imaging and 24-hour urine studies available. For each patient a single computerized tomography axial area measurement was obtained of the visceral fat area. Hepatic steatosis was diagnosed by comparing the HU of regions from the liver and spleen. Univariate analysis was performed to compare patients with or without an elevated visceral fat area and hepatic steatosis. Multivariate linear and logistic regression was done to assess for variables associated with 24-hour urine parameters and stone composition. RESULTS: An elevated visceral fat area was associated with higher 24-hour urine sodium (175 vs 157 mg per day, p <0.036) and lower 24-hour urine pH (5.724 vs 6.478, <0.0001). Urine pH less than 6 (OR 2.52) was associated with hepatic steatosis. Low urine pH less than 6 (OR 11.1, p = 0.004) and stone volume greater than 65 mm3 (OR 5.12, p = 0.023) were associated with an elevated visceral fat area. Low urine pH less than 6 (OR 5.87) and visceral fat area greater than 48% (OR 5.33) were associated with uric acid stones. Linear regression demonstrated that the percent of visceral fat area was associated with lower 24-hour urine pH (ß-coefficient -0.438, p <0.0001). CONCLUSIONS: Noncontrast computerized tomography based diagnosis of visceral obesity is associated with low urine pH, high urinary sodium and uric acid stone formation. Hepatic steatosis is associated with low urine pH.