Youngjin Moon

Association between Postoperatively Developed Atrial Fibrillation and Long-Term Mortality after Esophagectomy in Esophageal Cancer Patients: An Observational Study

Background Newly developed atrial fibrillation (AF) in patients who have undergone an esophagectomy increases the incidence of postoperative complications. However, the clinical implications of AF have not been fully elucidated in these patients. This retrospective observational study investigated the predictors for AF and the effect of AF on the mortality in esophageal cancer patients undergoing esophagectomy. Methods This study evaluated 583 patients undergoing esophagectomy, from January 2005 to April 2012. AF was defined as newly developed postoperative AF requiring treatment. The risk factors for AF and the association between AF and mortality were evaluated. The long-term mortality was the all-cause mortality, for which the cutoff date was May 31, 2014. Results AF developed in 63 patients (10.8%). Advanced age (odds ratio [OR] 1.099, 95% confidence interval [CI] 1.056–1.144, P < 0.001), preoperative calcium channel blocker (CCB) (OR 2.339, 95% CI 1.143–4.786, P = 0.020), and angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) (OR 0.206, 95% CI 0.067–0.635, P = 0.006) were associated with the incidence of AF. The Kaplan-Meier curve showed a significantly lower survival rate in the AF group compared to the non-AF group (P = 0.045), during a median follow-up of 50.7 months. The multivariable analysis revealed associations between AF and the 1-year mortality (hazard ratio [HR] 2.556, 95% CI 1.430–4.570, P = 0.002) and between AF and the long-term mortality (HR 1.507, 95% CI 1.003–2.266, P = 0.049). Conclusions In esophageal cancer patients, the advanced age and the preoperative medications (CCB, ACEI or ARB) were associated with the incidence of AF. Furthermore, postoperatively developed AF was associated with mortality in esophageal cancer patients after esophagectomy, suggesting that a close surveillance might be required in patients who showed AF during postoperative period.

Protective effects of propofol against hydrogen peroxide-induced oxidative stress in human kidney proximal tubular cells

Background We investigated the protective effects of propofol in the HK-2 cell line of human kidney proximal tubular cells against hydrogen peroxide (H2O2)-induced oxidative stress. Methods After pretreatment with different concentrations of propofol (0 µM, 10 µM, 25 µM and 50 µM) for 30 minutes, HK-2 cells were exposed to 8 mM H2O2 for 4 hours. Cell death was assessed by measuring the percentage of lactate dehydrogenase (LDH) release and by counting viable cells. The nature of cell death was assessed by doubles-taining cells with fluorescein isothiocyanate-labeled Annexin V and propidium iodide, and then analyzing the cells using flow cytometry. Results After exposure to 8 mM H2O2 for 4 hours, the percentage of LDH release was 45.1 ± 4.2% and the number of viable HK-2 cells was 5.2 ± 6.0%. Pretreatment with propofol suppressed H2O2-induced LDH release in a concentration-dependent manner, reducing the percentage of LDH release to 38.1 ± 5.6%, 33.5 ± 6.3%, and 26.2 ± 3.8% of the controls at 10 µM, 25 µM and 50 µM propofol, respectively. Numbers of viable cells increased following propofol pretreatment, with 11.4 ± 10.9%, 19.5 ± 16.1%, and 32.4 ± 23.3% cell survival rates after pretreatment with 10 µM, 25 µM and 50 µM propofol, respectively. Analyses of flow cytometry showed that the propofol pretreatment decreased the percentage of necrotic and late apoptotic cells. Conclusions Propofol protects HK-2 human kidney proximal tubular cells against H2O2-induced oxidative stress.

Development of New End-Effector for Proof-of-Concept of Fully Robotic Multichannel Biopsy

This paper presents a novel end-effector designed for a teleoperation type robotic system to perform automated sampling for needle biopsies. The objectives of the robotic system are to realize teleoperation control of the pose and position of the biopsy instrument to reduce X-ray exposure and enhance the precision and accuracy of the procedure as well as to automate the sequence of multiple samplings during the biopsy. In order to realize the desired functions, the end-effector comprises three modules: the needle cartridge, needle positioning mechanism, and needle driving unit. The detachable needle cartridge contains six needle sets: one guide needle and five sampling needles. It rotates itself to change needles and rotates the needle body to adjust the facing angle of the needle tip. The needle positioning mechanism is spherical with two degrees of freedom and is a modification of the typical hemisphere type. The needle driving unit controls the needle grab/release and insertion/retreat motions. A concept design and prototype were developed with an experimental master-salve system for the teleoperation. The experimental results successfully demonstrated the feasibility of the robotic biopsy procedure.

Design and Kinematic Analysis of a New End-Effector for a Robotic Needle Insertion-Type Intervention System

This paper presents a new end-effector as a key component for a robotic needle insertion-type intervention system and its kinematic analysis. The mechanism is designed as a spherical mechanism with a revolute joint and a curved sliding joint, and its links always move on the surface of a sphere. The remote centre of motion (RCM) of the designed mechanism is placed below the base of the mechanism to avoid contact with the patients body, unlike the conventional end-effectors developed for needle insertion. For the proposed mechanism, the forward kinematics are solved in terms of input joint parameters and then the reverse kinematics are solved by using the cross-product relationship between each joint vector and a vector mutually perpendicular to the vectors. The kinematic solutions are confirmed by numerical examples.

Effect of ventriculo-arterial coupling on transplant outcomes in cirrhotics: Analysis of pressure-volume curve relations

BACKGROUND & AIMSnVentriculo-arterial coupling (VAC) reflects the interaction between ventricular performance and effective arterial load. Current criteria for cirrhotic cardiomyopathy focus only on cardiac function without addressing the effect of hyperdynamic, low-resistance circulation. We investigated alterations in VAC in cirrhotic patients and their associations with post-liver transplant all-cause mortality.nnnMETHODSnIn this single institution cohort study, cirrhotic patients who underwent liver transplantation (LT) (n=914) were retrospectively compared with healthy matched controls using noninvasively measured end-systolic ventricular elastance (Ees), arterial elastance (Ea), and VAC (Ea/Ees). All-cause mortality based on VAC values were investigated using a Cox hazard model with the inverse probability treatment weighting (IPTW) of propensity score.nnnRESULTSnCirrhotic patients had significantly lower Ees, Ea and VAC values than controls. Over a median of 30months, 96 patients died after LT. In patients with a high model for end-stage liver disease score (⩾25), VAC of >0.61 (highest tertile) had poorer survival outcomes than patients with VAC of ⩽0.50 (lowest tertile) (66.0% vs. 91.8%; Log-rank p=0.001), and was independently associated with risk of mortality (hazard ratio, 2.44; 95% CI, 1.10-5.39; p=0.028) compared with VAC of ⩽0.61 after IPTW adjustment.nnnCONCLUSIONSnIn cirrhotic patients, ventricular elastance and VAC values are lower than those in controls. However, in advanced cirrhotic patients, an increase in VAC value is associated with all-cause mortality after LT, suggesting that this non-invasive estimation of ventriculo-arterial uncoupling is an additional novel prognosticator in cirrhotic cardiovascular disorders.nnnLAY SUMMARYnIn cirrhotic patients, cardiac dysfunction is latent and only manifests under stressful conditions because of arterial vasodilation. In this study, based on the pressure-volume curve of cardiac function, we investigated characteristics of the ventricular-arterial coupling in cirrhotic patients and further found that disparities in the ventriculo-arterial relationship are associated with graft failure and all-cause mortality after liver transplantation.

Development of a robotic mechanism for teleoperation-based needle interventions

This paper presents a new robot for interventions using needles. The main objective of the robot is to be able to do multi-channel biopsy, automatically conduct repeated task, and adjust the angle between the robot base and the end of macro-motion robot. In order to implement the desired functions, three modules are designed: a needle cartridge, needle positioning mechanism, and needle driving unit. The detachable needle cartridge contains six needles for five sampling, rotates itself for sampling slot change, and rotates needles for needle-tip angle change. The needle positioning mechanism is devised as a two degree of freedom spherical mechanism but not a typical hemisphere type. The needle driving unit controls two hooks which hold or release needles. The concept design for three components was created and then the prototype was made. It was confirmed that desired functions can be achieved.

A compliant parallel mechanism for needle intervention

This paper presents a compliant mechanism for fine motion of a medical robot for needle intervention procedure. The concept of this mechanism is created with the purpose of correcting a needle axis by translating a main robot for needle driving when an unexpected slip happens in needle insertion. In order to specify the concept, a planar compliant mechanism is designed so that the mechanism has maximized workspace for some given design condition. A simplified mathematical model for the designed mechanism is derived and then a pose controller is designed to track a desired trajectory in a plane, which is a similar situation that the compliant mechanism translates a needle driving robot to correct the direction of a needle. The simulation result shows good tracking performance.

Implications d’une bronche trachéale sur la ventilation à un seul poumon et la bronchoscopie par fibre optique chez un patient subissant une chirurgie thoracique: une étude de cas

PurposeDue to its anatomical complexity, a tracheal bronchus has important clinical implications for one-lung ventilation (OLV). We present a case of successful OLV in a patient with a high a type I (i.e., high take-off) tracheal bronchus. This anomaly presented unusual fibreoptic bronchoscopic (FOB) views that were difficult to discern from the normal carinal bifurcation.Clinical featuresA 35-yr-old male presented for posterior basal segmentectomy of the left lower lobe under video-assisted thoracoscopy. The preoperative chest radiography was reported as normal, but a computed tomography scan of the chest revealed a right upper lobe tracheal bronchus. The inlet of the tracheal bronchus was located high above the carina, and the distal trachea had significant narrowing. Because the main trachea was divided into a tracheal bronchus and a distal trachea with similar diameters and with an acute angle of divergence, FOB views of the tracheal bronchus take-off appeared similar to the normal carinal bifurcation. Moreover, the actual carina had an atypical appearance with the main bronchi shifted laterally and a blunted carinal ridge. As a result of this atypical tracheobronchial anatomy, we used an Arndt endobronchial blocker system instead of a double-lumen tube (DLT) for right-sided OLV. One-lung ventilation was satisfactory throughout the uncomplicated operation.ConclusionCareful preoperative assessment of tracheobronchial anatomy is imperative in order to choose an appropriate method of OLV and prevent potential complications. In a type I tracheal bronchus with a narrowed distal trachea, a bronchial blocker may have advantages over the conventional DLT in achieving OLV.RésuméObjectifCompte tenu de sa complexité anatomique, une bronche trachéale a d’importantes implications cliniques sur la ventilation à un seul poumon (OLV). Nous présentons un cas d’OLV réussie chez un patient ayant un type I haut, c’est-à-dire un embranchement haut-situé de la bronche trachéale. En bronchoscopie à fibre optique (FOB), cette anomalie présentait des images peu communes difficiles à discerner d’une carène de bifurcation normale.Caractéristiques cliniquesUn homme âgé de 35xa0ans a été hospitalisé pour segmentectomie basale postérieure du lobe inférieur gauche par thoracoscopie assistée par vidéo. La radiographie préopératoire du thorax a été décrite comme normale, mais une tomodensitométrie du thorax a révélé une bronche trachéale du lobe supérieur droit. Le départ de la bronche trachéale était situé haut par rapport à la carène et la trachée distale était significativement rétrécie. Dans la mesure où la trachée proprement dite se divisait en bronche trachéale et en trachée distale, aux diamètres semblables et avec une bifurcation formant un angle aigu, les vues en FOB du départ de la bronche trachéale ressemblaient à celles d’une carène normale. De plus, la véritable carène avait un aspect atypique avec des bronches souches déplacées latéralement et une crête de carène émoussée. Du fait de cette anatomie trachéobronchique atypique, nous avons utilisé un système de blocage endobronchique d’Arndt à la place d’un tube à double lumière (DLT) pour une OLV du côté droit. La ventilation unilatérale a été satisfaisante tout au long de l’intervention qui s’est déroulée sans complication.ConclusionUne évaluation préopératoire soigneuse de l’anatomie trachéobronchique est impérative pour choisir une méthode appropriée d’OLV et prévenir les complications potentielles. Dans le cas d’une bronche trachéale de typexa0I avec trachée distale rétrécie, un bloqueur bronchique peut avoir des avantages par rapport à un DLT conventionnel pour la réalisation d’une OLV.

The implications of a tracheal bronchus on one-lung ventilation and fibreoptic bronchoscopy in a patient undergoing thoracic surgery: a case report

PurposeDue to its anatomical complexity, a tracheal bronchus has important clinical implications for one-lung ventilation (OLV). We present a case of successful OLV in a patient with a high a type I (i.e., high take-off) tracheal bronchus. This anomaly presented unusual fibreoptic bronchoscopic (FOB) views that were difficult to discern from the normal carinal bifurcation.Clinical featuresA 35-yr-old male presented for posterior basal segmentectomy of the left lower lobe under video-assisted thoracoscopy. The preoperative chest radiography was reported as normal, but a computed tomography scan of the chest revealed a right upper lobe tracheal bronchus. The inlet of the tracheal bronchus was located high above the carina, and the distal trachea had significant narrowing. Because the main trachea was divided into a tracheal bronchus and a distal trachea with similar diameters and with an acute angle of divergence, FOB views of the tracheal bronchus take-off appeared similar to the normal carinal bifurcation. Moreover, the actual carina had an atypical appearance with the main bronchi shifted laterally and a blunted carinal ridge. As a result of this atypical tracheobronchial anatomy, we used an Arndt endobronchial blocker system instead of a double-lumen tube (DLT) for right-sided OLV. One-lung ventilation was satisfactory throughout the uncomplicated operation.ConclusionCareful preoperative assessment of tracheobronchial anatomy is imperative in order to choose an appropriate method of OLV and prevent potential complications. In a type I tracheal bronchus with a narrowed distal trachea, a bronchial blocker may have advantages over the conventional DLT in achieving OLV.RésuméObjectifCompte tenu de sa complexité anatomique, une bronche trachéale a d’importantes implications cliniques sur la ventilation à un seul poumon (OLV). Nous présentons un cas d’OLV réussie chez un patient ayant un type I haut, c’est-à-dire un embranchement haut-situé de la bronche trachéale. En bronchoscopie à fibre optique (FOB), cette anomalie présentait des images peu communes difficiles à discerner d’une carène de bifurcation normale.Caractéristiques cliniquesUn homme âgé de 35xa0ans a été hospitalisé pour segmentectomie basale postérieure du lobe inférieur gauche par thoracoscopie assistée par vidéo. La radiographie préopératoire du thorax a été décrite comme normale, mais une tomodensitométrie du thorax a révélé une bronche trachéale du lobe supérieur droit. Le départ de la bronche trachéale était situé haut par rapport à la carène et la trachée distale était significativement rétrécie. Dans la mesure où la trachée proprement dite se divisait en bronche trachéale et en trachée distale, aux diamètres semblables et avec une bifurcation formant un angle aigu, les vues en FOB du départ de la bronche trachéale ressemblaient à celles d’une carène normale. De plus, la véritable carène avait un aspect atypique avec des bronches souches déplacées latéralement et une crête de carène émoussée. Du fait de cette anatomie trachéobronchique atypique, nous avons utilisé un système de blocage endobronchique d’Arndt à la place d’un tube à double lumière (DLT) pour une OLV du côté droit. La ventilation unilatérale a été satisfaisante tout au long de l’intervention qui s’est déroulée sans complication.ConclusionUne évaluation préopératoire soigneuse de l’anatomie trachéobronchique est impérative pour choisir une méthode appropriée d’OLV et prévenir les complications potentielles. Dans le cas d’une bronche trachéale de typexa0I avec trachée distale rétrécie, un bloqueur bronchique peut avoir des avantages par rapport à un DLT conventionnel pour la réalisation d’une OLV.

Comparison of acute kidney injury between open and laparoscopic liver resection: Propensity score analysis

The inflammatory response has been shown to be a major contributor to acute kidney injury. Considering that laparoscopic surgery is beneficial in reducing the inflammatory response, we compared the incidence of postoperative acute kidney injury between laparoscopic liver resection and open liver resection. Among 1173 patients who underwent liver resection surgery, 222 of 926 patients who underwent open liver resection were matched with 222 of 247 patients who underwent laparoscopic liver resection, by using propensity score analysis. The incidence of postoperative acute kidney injury assessed according to the creatinine criteria of the Kidney Disease: Improving Global Outcomes definition was compared between those 1:1 matched groups. A total 77 (6.6%) cases of postoperative acute kidney injury occurred. Before matching, the incidence of acute kidney injury after laparoscopic liver resection was significantly lower than that after open liver resection [1.6% (4/247) vs. 7.9% (73/926), P < 0.001]. After 1:1 matching, the incidence of postoperative acute kidney injury was still significantly lower after laparoscopic liver resection than after open liver resection [1.8% (4/222) vs. 6.3% (14/222), P = 0.008; odds ratio 0.273, 95% confidence interval 0.088–0.842, P = 0.024]. The postoperative inflammatory marker was also lower in laparoscopic liver resection than in open liver resection in matched set data (white blood cell count 12.7 ± 4.0 × 103/μL vs. 14.9 ± 3.9 × 103/μL, P < 0.001). Our findings suggest that the laparoscopic technique, by decreasing the inflammatory response, may reduce the occurrence of postoperative acute kidney injury during liver resection surgery.