Jae Moon Choi

Coronary Computed Tomography Angiography in Combination with Coronary Artery Calcium Scoring for the Preoperative Cardiac Evaluation of Liver Transplant Recipients

Liver transplantation is the best treatment option for early-stage hepatocellular carcinoma, liver cirrhosis, fulminant liver failure, and end-stage liver diseases. Even though advances in surgical techniques and perioperative care have improved postoperative outcomes, perioperative cardiovascular complications are a leading cause of postoperative morbidity and mortality following liver transplantation. Ischemic coronary artery disease (CAD) and cardiomyopathy are the most common cardiovascular diseases and could be negative predictors of postoperative outcomes in liver transplant recipients. Therefore, comprehensive cardiovascular evaluations are required to assess perioperative risks and prevent concomitant cardiovascular complications that would preclude good outcomes in liver transplant recipients. The two major types of cardiac computed tomography are the coronary artery calcium score (CACS) and coronary computed tomography angiography (CCTA). CCTA in combination with the CACS is a validated noninvasive alternative to coronary angiography for diagnosing and grading the severity of CAD. A CACS > 400 is associated with significant CAD and a known important predictor of posttransplant cardiovascular complications in liver transplant recipients. In this review article, we discuss the usefulness, advantages, and disadvantages of CCTA combined with CACS as a noninvasive diagnostic tool for preoperative cardiac evaluation and for maximizing the perioperative outcomes of liver transplant recipients.

Spectral analysis of respiratory-related hemodynamic variables in simulated hypovolemia: a study in healthy volunteers with spontaneous breathing using a paced breathing activity

Background A dynamic preload index such as stroke volume variation (SVV) is not as reliable in spontaneous breathing (SB) patients as in mechanically ventilated patients. This study examined the hypothesis that spectral analysis of hemodynamic variables during paced breathing (PB) activity may be a feasible index of volume changes and fluid responsiveness, despite insufficient respiratory changes in the preload index during SB activity. Methods Blood pressure and stroke volume (SV) were measured in 16 subjects undergoing PB (15 breaths/min), using a Finometer device and the Modelflow method. Respiratory systolic pressure variation (SPV) and SVV were measured and respiratory frequency (RF, 0.2-0.3 Hz) of power spectra of SPV (SPVRF) and SVV (SVVRF) were computed using fast Fourier transformation. Progressive hypovolemia was simulated with lower body negative pressure (LBNP). Volume challenges were produced by infusion of normal saline and subsequent release of LBNP to baseline. Fluid responsiveness, defined as a >20% increase in SV, was assessed by the area under the curve (AUC) of receiver operating characteristic curves. Results Graded hypovolemia caused a significant increase in SPVRF and a decrease in SVVRF. During volume expansion, SPVRF decreased and SVVRF rose significantly. Fluid responsiveness was better predicted with SVVRF (AUC 0.75) than with SPVRF, SPV, or SVV. SVVRF before volume challenge was significantly correlated with volume expansion-induced changes in SV (r = -0.64). Conclusions These results suggest that RF spectral analysis of dynamic preload variables may enable the detection of volume change and fluid responsiveness in SB hypovolemic patients performing PB activity.

Effects of the Trendelenburg Position and Positive End-Expiratory Pressure on the Internal Jugular Vein Cross-Sectional Area in Children With Simple Congenital Heart Defects.

AbstractCatheterization of the internal jugular vein (IJV) remains difficult in pediatric populations. Increasing the cross-sectional area (CSA) of the IJV facilitates cannulation and decreases complications. We aimed to evaluate the Trendelenburg position and the levels of positive end-expiratory pressure (PEEP) at which the maximum increase of CSA of the IJV occurred in children undergoing cardiac surgery.In this prospective study, the CSA of the right IJV was assessed using ultrasound in 47 anesthetized pediatric patients with simple congenital heart defects. The baseline CSA was obtained in response to a supine position with no PEEP and compared with 5 different randomly ordered maneuvers, that is, a PEEP of 5 and 10 cm H2O in a supine position and of 0, 5, and 10 cm H2O in a 10° Trendelenburg position. Hemodynamic variables, including blood pressure and heart rate, maximum and minimum diameters, and CSA, were measured.All maneuvers increased the CSA of the right IJV with respect to the control condition. In the supine position, the CSA was increased by 9.4% with a PEEP of 5 and by 19.5% with a PEEP of 10 cm H2O. The Trendelenburg tilt alone increased the CSA by 19.0%, and combining the 10° Trendelenburg with a 10 cm H2O PEEP resulted in the largest IJV CSA increase (33.3%) compared with the supine position with no PEEP. Meanwhile, vital signs remained relatively steady during the experiment.The application of the Trendelenburg position and a 10 cm H2O PEEP thus significantly increases the CSA of the right IJV, perhaps improving the chances of successful cannulation in pediatric patients with simple congenital heart defects.

Risk factors for pulmonary complications after percutaneous nephrolithotomy: A retrospective observational analysis.

AbstractAlthough percutaneous nephrolithotomy is minimally invasive, it is associated with several complications, including extravasation of fluid and urine, the need for a blood transfusion, and septicemia. However, little is known about pulmonary complications after this procedure. Therefore, we aimed to evaluate the risk factors for and outcomes of pulmonary complications after percutaneous nephrolithotomy.All consecutive patients who underwent percutaneous nephrolithotomy between 2001 and 2014 were identified and divided into group A (no clinically significant pulmonary complications) and group B (clinically significant pulmonary complications). Preoperative and intraoperative variables and postoperative outcomes were evaluated. Independent risk factors for postoperative pulmonary complications were evaluated by univariate and multivariate logistic regression analyses.The study included 560 patients: 378 (67.5%) in group A and 182 (32.5%) in group B. Multivariate logistic regression analysis revealed that the independent risk factors for pulmonary complications after percutaneous nephrolithotomy were a higher body mass index (odds ratio = 1.062, P = 0.026), intraoperative red blood cell transfusion (odds ratio = 2.984, P = 0.012), and an intercostal surgical approach (odds ratio = 3.046, P < 0.001). Furthermore, the duration of hospital stay was significantly longer (8.4 ± 4.3 days vs 7.6 ± 3.4 days, P = 0.010) and the intensive care unit admission rate was significantly higher [13 (7.1%) vs 1 (0.3%), P < 0.001] in group B than in group A.Risk factors for pulmonary complications after percutaneous nephrolithotomy were a higher body mass index, intraoperative red blood cell transfusion, and an intercostal surgical approach. Postoperative pulmonary complications were associated with poor outcomes. These results may provide useful information for the perioperative management of pulmonary complications after percutaneous nephrolithotomy.

Relationship between Stroke Volume Variation and Blood Transfusion during Liver Transplantation

Background. Intraoperative blood transfusion increases the risk for perioperative mortality and morbidity in liver transplant recipients. A high stroke volume variation (SVV) method has been proposed to reduce blood loss during living donor hepatectomy. Herein, we investigated whether maintaining high SVV could reduce the need for blood transfusion and also evaluated the effect of the high SVV method on postoperative outcomes in liver transplant recipients. Methods. We retrospectively analyzed 332 patients who underwent liver transplantation, divided into control (maintaining <10% of SVV during surgery) and high SVV (maintaining 10-20% of SVV during surgery) groups. We evaluated the blood transfusion requirement and hemodynamic parameters, including SVV, as well as postoperative outcomes, such as incidences of acute kidney injury, durations of postoperative intensive care unit and hospital stay, and rates of 1-year mortality. Results. Mean SVV values were 7.0% ± 1.3% in the control group (n = 288) and 11.2% ± 1.8% in the high SVV group (n = 44). The median numbers of transfused packed red blood cells and fresh frozen plasmas in the high SVV group were significantly lower than those in control group (0 vs. 2 units, P = 0.003; and 0 vs. 3 units, P = 0.033, respectively). No significant between-group differences were observed for postoperative outcomes. Conclusions. Maintaining high SVV can reduce the blood transfusion requirement during liver transplantation without worsening postoperative outcomes. These findings provide insights into improving perioperative management in liver transplant recipients.

Blind nasal intubation as an alternative to difficult intubation approaches

Airway difficulties are a major concern for anesthesiologists. Even though fiberoptic intubation is the generally accepted method for management of difficult airways, it is not without disadvantages-requires patient cooperation, and cannot be performed on soiled airway or upper airways with pre-existing narrowing pathology. Additionally, fiberoptic bronchoscopy is not available at every medical institution. In this case, we encountered difficult airway management in a 71-year-old man with a high Mallampati grade and a thick neck who had undergone urologic surgery. Several attempts, including a bronchoscope-guided intubation, were unsuccessful. Finally, blind nasal intubation was successful while the patients neck was flexed and the tracheal cartilage was gently pressed down. We suggest that blind nasal intubation is a helpful alternative in difficult airway management and it can be a lifesaving technique in emergencies. Additionally, its simplicity makes it a less expensive option when advanced airway technology (fiberoptic bronchoscopy) is unavailable.

Malignant hyperthermia and dantrolene sodium

in Korea. The patient was treated with conventional methods including dantrolene, but the patient’s condition became aggravated, requiring the application of an extracorporeal membrane oxygenator (ECMO) to support cardiopulmonary resuscitation [1]. However, if the patient had been treated by prompt administration of dantrolene (i.e., within 20 minutes), we wonder how the patient’s clinical course may have progressed. According to the European Malignant Hyperthermia Group guidelines for management of malignant hyperthermia, at least 36 vials of 20 mg dantrolene should be prepared within 10–15 minutes to effectively treat the condition. However, dantrolene is expensive and has a short life span; thus, routine preparation of dantrolene may not be cost effective [2]. In a previous report, it was noted that many hospitals were not prepared to provide the recommended dose of 36 vials of dantrolene [3]. Although the preparation of 36 vials is not necessarily cost-effective, preparation of the first dose is recommended to prevent serious complications involving reduced mortality, as well as to provide the anesthesiologist with time to prepare the second dose of dantrolene [4]. Therefore, it is necessary to reorganize the current system, in which dantrolene is prepared only in single base hospitals in each region; we propose that the system should be modified to ensure preparation of the first dose of dantrolene such that it can be readily administered in each hospital. We expect that this would enable the first dose of dantrolene to be administered in a much faster time interval than in the current system; this could save patients by reducing associated mortality and morbidity. In addition, patients who express some symptoms and signs that are similar to malignant hyperthermia may not be confirmed as cases of malignant hyperthermia. Therefore, an additional system should be prepared to enable prompt patient transfer to the malignant hyperthermia center; moreover, the caffeine-halothane contracture test and gene test should be available, which can be used for diagnosis and further assistance of patients and their families. This would facilitate prevention of malignant hyperthermia in the future and provide necessary information to the medical providers. We think that a properly equipped malignant hyperthermia center is essential to confirm diagnosis and support affected patients in Korea.