Youn Joung Cho

Influence of high-dose intraoperative remifentanil with intravenous ibuprofen on postoperative morphine consumption in patients undergoing pancreaticoduodenectomy: a randomized trial.

STUDY OBJECTIVE High-dose remifentanil during surgery paradoxically increases postoperative pain intensity and morphine consumption. Cyclooxygenase inhibitors decrease prostaglandin synthesis, thereby antagonizing N-methyl-d-aspartate receptor activation, and may reduce hyperalgesia. This study was performed to evaluate whether postoperative morphine consumption increased following intraoperative continuous remifentanil infusion and whether this could be prevented by intravenous ibuprofen pretreatment. DESIGN A randomized controlled study. SETTING Single university hospital, study period from September 2014 to March 2015. PATIENTS One hundred and twenty patients undergoing pancreaticoduodenectomy. INTERVENTIONS After induction of anesthesia, patients received remifentanil target-controlled infusion (effect site concentration of 4 ng/mL or 1 ng/mL) with or without intravenous ibuprofen (800 mg). MEASUREMENTS Postoperative cumulative total morphine consumption and pain intensity were assessed. MAIN RESULTS Intraoperative remifentanil use in patients receiving high-dose remifentanil was more than 3-fold higher than that in patients receiving low-dose remifentanil (2666.8 ± 858.4 vs 872.0 ± 233.3 μg, respectively; P< .001). However, cumulative total morphine consumption at postoperative 1, 3, 6, 12, 24, and 48 hours did not differ among the groups. There were no differences among the groups in the self-administered analgesic dose by the patients using a controlled analgesia device, number of self-administration attempts, numerical rating scale for pain, or analgesic side effects. CONCLUSIONS We found no influence on postoperative pain after high-dose remifentanil in patients undergoing pancreaticoduodenectomy. Addition of intravenous ibuprofen did not reduce postoperative morphine consumption or pain intensity.

Microvascular reactivity and clinical outcomes in cardiac surgery

IntroductionMicrovascular reactivity is decreased in patients with septic shock; this is associated with worse clinical outcomes. The objectives of the present study were to investigate microvascular reactivity in cardiac surgery patients and to assess any association with clinical outcomes.MethodsWe retrospectively analyzed a prospectively collected registry. In total, 254 consecutive adult patients undergoing cardiac and thoracic aortic surgeries from January 2013 through May 2014 were analyzed. We performed a vascular occlusion test (VOT) by using near-infrared spectroscopy to measure microvascular reactivity. VOT was performed three times per patient: prior to the induction of anesthesia, at the end of surgery, and on postoperative day 1. The primary endpoint was a composite of major adverse complications, including death, myocardial infarction, acute kidney injury, acute respiratory distress syndrome, and persistent cardiogenic shock.ResultsVOT recovery slope decreased during the surgery. VOT recovery slope on postoperative day 1 was significantly lower in patients with composite complications than those without (3.1 ± 1.6 versus 4.0 ± 1.5 %/s, P = 0.001), although conventional hemodynamic values, such as cardiac output and blood pressure, did not differ between the groups. On multivariable regression and linear analyses, low VOT recovery slope on postoperative day 1 was associated with increases of composite complications (odds ratio 0.742; 95 % confidence interval (CI) 0.584 to 0.943; P = 0.015) and hospital length of stay (regression coefficient (B) −1.276; 95 % CI −2.440 to −0.112; P = 0.032).ConclusionMicrovascular reactivity largely recovered on postoperative day 1 in the patients without composite complications, but this restoration was attenuated in patients with composite complications.Trial registrationClinicalTrials.gov NCT01713192. Registered 22 October 2012.

Effects of delayed remote ischemic preconditioning on peri-operative myocardial injury in patients undergoing cardiac surgery — A randomized controlled trial

BACKGROUND Remote ischemic preconditioning (RIPC) has two time windows for organ protection: acute and delayed. Previous studies have mainly focused on the acute time window to evaluate organ protection by RIPC. We evaluated myocardial protection by delayed RIPC in adult patients undergoing cardiac surgery. METHODS A total of 160 adult patients undergoing cardiac surgery with cardiopulmonary bypass were randomized to receive either delayed RIPC (four cycles of 5min of ischemia followed by 5min of reperfusion by inflation to 200mmHg and deflation of a blood pressure cuff on the upper arm) or the control treatment 24-48h before surgery. The primary endpoint was post-operative troponin I levels serially measured for 72h. Secondary endpoints included post-operative serum creatinine levels, acute kidney injury, and composite complications. RESULTS There were no significant differences in post-operative troponin I values. The incidence of acute kidney injury, defined by the Acute Kidney Injury Network staging system, was lower in the delayed RIPC group compared to the control group (30.0% vs. 47.5%; relative risk, 0.768; 95% confidence interval, 0.599-0.985; p=0.023). Moreover, the occurrence of composite complications was lower in the delayed RIPC group compared with the control group (65.0% vs. 81.3%; relative risk, 0.536; 95% confidence interval, 0.311-0.924; p=0.020). CONCLUSIONS While RIPC did not provide cardioprotective effects in patients undergoing cardiac surgery, it appeared to reduce acute kidney injury, as well as the rate of composite complications.

Long-term clinical outcomes of Remote Ischemic Preconditioning and Postconditioning Outcome (RISPO) trial in patients undergoing cardiac surgery

BACKGROUND Remote ischemic conditioning has been shown to confer myocardial protection. However, there is still no sufficient data on its long-term clinical outcomes. We analyzed the long-term results of the Remote Ischemic Preconditioning and Postconditioning Outcome (RISPO) trial in cardiac surgery patients. METHODS In the RISPO trial, 1280 patients were randomized to receive remote ischemic preconditioning (RIPC) with postconditioning (RIPostC, upper arm ischemia by four cycles of 5-min inflation followed by 5-min deflation of a pneumatic cuff, N=644) or sham (N=636) during cardiac surgery. Patient follow-up data were collected by review of medical records, telephone interviews, and from the National Statistical Office. The primary endpoint was major adverse cardiac and cerebrovascular events (MACCE; a composite of all-cause mortality, myocardial infarction (MI), stroke, and revascularization), and the secondary endpoints were the individual components of the primary endpoint. RESULTS At completion of follow-up (mean 44months), there was no difference in MACCE between the groups (90 [14.0%] versus 101 [15.9%] in the RIPC with RIPostC versus control groups; hazard ratio [HR], 0.893; 95% confidence interval [CI], 0.672-1.187; P=0.435). However, MI was reduced to half in the RIPC with RIPostC group (10 [1.6%] versus 23 [3.6%]; HR, 0.468; 95% CI, 0.222-0.984; P=0.045). CONCLUSIONS Remote ischemic preconditioning with RIPostC did not improve long-term MACCE after cardiac surgery. However, MI was reduced in the RIPC with RIPostC group compared with the control group during the follow-up period. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov identifier, NCT00997217.

Guidewire malposition during central venous catheterization despite the use of ultrasound guidance

Central venous catheterization has become a mandatory part of clinical management in a variety of circumstances. It is a safe procedure in most patients, but it may be associated with a number of complications such as arterial puncture, hematoma, and malposition [1]. Ultrasound guidance for catheterization has become an accepted tool to improve the success rate and to reduce the number of attempts and complications. However, it does not prevent all complications. We encountered a case of the inadvertent insertion of a guidewire into the suspected subcutaneous area despite the use of ultrasound guidance. A 77-year-old woman (body mass index 15.9 kg/m2) presented for vertebral corpectomy under suspicion of infectious spondylitis of the T12-L1 vertebrae. Her medical history included hypertension and previous operation for a compression fracture of the T12 and L1 vertebral bodies. Because the current operation needed to be performed in the prone position, anesthesia was induced on a stretcher, from which the patient would be moved to a prone position on the operating table. Monitoring with electrocardiography, non-invasive blood pressure, pulse oximetry, and bispectral index, anesthesia was induced and maintained by target-controlled propofol and remifentanil. Rocuronium was injected to facilitate tracheal intubation. After the muscles were relaxed, her right radial artery was cannulated for continuous invasive blood pressure monitoring, and the trachea was intubated and mechanical ventilation was started. Central venous catheterization was planned for venous access and hemodynamic monitoring. The patients head was turned slightly towards the left while preventing extreme rotation, which leads to overlapping of the internal jugular vein (IJV) and the common carotid artery. The patients right anterior neck was prepped in a sterile manner. Next, the ultrasound probe was covered with a sterile sheath. The right IJV was assessed at the level of the cricoid cartilage using B-mode duplex sonography with a 5- to 13-MHz linear transducer (LOGIQe; GE Medical, Jinagsu, China) using a standardized technique applying minimal probe pressure to obtain an adequate image. The size of the IJV looked rather small, and the patient seemed to be dehydrated or in a hypovolemic state. Intravenous fluid was administered, and positive end-expiratory pressure (PEEP) of 10 cmH2O was applied to increase the size of the IJV. A short-axis approach was used with dynamic ultrasound guidance during needle puncture. The operator controlled the needle with assistance by the attending anesthesiologist, who held the transducer with sterile sheath. The needle tip was visualized within the vessel, and dark venous blood regurgitation was confirmed through the syringe in a single attempt. Then, the ultrasound probe was taken off and the guidewire was introduced without significant resistance. However, subsequent ultrasonography using short- and long-axis views revealed that the guidewire was located in the surrounding subcutaneous tissue rather than within the vessel (Fig. 1A). Fig. 1 Malposition of guidewire (arrows) in the suspected subcutaneous area (A). Pulse wave Doppler revealed that the guidewire (arrows) was located in the vein (B). The guidewire was removed and then another needle puncture was attempted in which subsequent placement of a new guidewire was achieved uneventfully with ultrasonographic guidance. The intravascular location of the new guidewire was confirmed by rescanning the vein in both short- and long-axis views. Subsequent pulse-wave Doppler also revealed that the guidewire was located within the vein (Fig. 1B). After confirming the position of the guidewire, 7-Fr double-lumen central venous catheter (Arrow International, Inc., Reading, PA) was inserted over the wire and advanced into the IJV. One explanation for the occurrence of the complications despite using ultrasound guidance is that the ultrasound beam is narrow, and although the operator appears to be following the tip of the needle in the vessel on the image, the real tip could actually have passed beyond the ultrasound beam and out through the contralateral wall of the vessel [2]. Furthermore, real-time imaging with ultrasound shows significant compression of the vein when a needle punctures the skin overlying the vein before entry into the lumen. The force applied to puncture the anterior wall of the vessel usually causes perforation of the posterior wall when the distance between the anterior and the posterior wall is small [3]. In our case, the patients vein looked small in size. Thus, intravenous fluid was administered for volume support, and end-expiratory positive pressure of 10 cmH2O was applied to increase the cross-sectional area of the IJV [4]. The Trendelenburg tilt position can also dilate the IJV by increasing the height between the right atrium and the right IJV, which decreases venous return to the heart via the superior vena cava, and hence potentially increases the chances of successful jugular cannulation [4]. Unfortunately, the stretcher where the anesthesia was conducted in our case was not able to take the Trendelenburg tilt position because of its equipment control limitation. It is notable that incorrectly placing the needle outside of the targeted vessel can occur after passage through the vessel and concomitant blood withdrawal into the syringe [5]. The closer the needle tip is to the posterior wall, the more likely it is to migrate through the wall [5]. In our case, blood regurgitation was successful through the guide needle but it did not exclude malposition of the guidewire. We suspect that in the first attempt to insert the guidewire, the guidewire tip penetrated the collapsed fragile vein, and it then was misplaced in an extravascular location. In the subsequent trial, we checked proper guidewire position with a long-axis view and pulse-wave Doppler. Checking the long-axis view and pulse-wave Doppler can be performed in mere seconds and would give great accuracy without requiring extra equipment. Although the initial introduction of the guidewire was uneventful, ultrasonography revealed unintended malposition of the guidewire, therefore preventing potential malposition of the catheter. It is important to note that even with use of an ultrasound-guided procedure, an unrecognized complication can occur. In light of the current report, the clinician may wish to consider the need for a long-axis view and pulse-wave Doppler in addition to the usual short-axis method during central venous catheterization, even if the insertion proceeded smoothly and without apparent difficulties.

Comparison of Needle Insertion and Guidewire Placement Techniques During Internal Jugular Vein Catheterization: The Thin-Wall Introducer Needle Technique Versus the Cannula-Over-Needle Technique.

Objectives:For needle insertion and guidewire placement during central venous catheterization, a thin-wall introducer needle technique and a cannula-over-needle technique have been used. This study compared these two techniques regarding the success rates and complications during internal jugular vein catheterization. Design:Prospective, randomized, controlled study. Setting:A university-affiliated hospital. Patients:Two hundred sixty-six patients scheduled for thoracic surgery, gynecologic surgery, or major abdominal surgery, who required central venous catheterization. Interventions:Patients were randomly assigned to either the thin-wall introducer needle group (n = 134) or the cannula-over-needle group (n = 132). Central venous catheterization was performed on the right internal jugular vein under assistance with real-time ultrasonography. Needle insertion and guidewire placement were performed using a thin-wall introducer needle technique in the thin-wall introducer needle group and a cannula-over-needle technique in the cannula-over-needle group. Measurements and Main Results:The guidewire placement on the first skin puncture was regarded as a successful guidewire insertion on the first attempt. The number of puncture attempts for internal jugular vein catheterization was recorded. Internal jugular vein was assessed by ultrasonography to identify complications. The rate of successful guidewire insertion on the first attempt was higher in the thin-wall introducer needle group compared with the cannula-over-needle group (87.3% vs 77.3%; p = 0.037). There were fewer puncture attempts in the thin-wall introducer needle group than in the cannula-over-needle group (1.1 ± 0.4 vs 1.3 ± 0.6; p = 0.026). There was no significant difference in complications of internal jugular vein catheterization between the two groups. Conclusions:The thin-wall introducer needle technique showed a superior success rate for first attempt of needle and guidewire insertion and required fewer puncture attempts during internal jugular vein catheterization.

Neutrophil, Lymphocyte, and Platelet Counts and Acute Kidney Injury After Cardiovascular Surgery

OBJECTIVE Postoperative low platelet count and perioperative high neutrophil/lymphocyte (N/L) ratio are associated with acute kidney injury (AKI) and mortality after cardiac surgery. The authors investigated whether (1) their combination neutrophil/lymphocyte × platelet (N/LP) ratio is an independent predictor of AKI and postoperative mortality and (2) whether the N/LP ratio increases predictive ability compared with the N/L ratio or platelet nadir. DESIGN This was a retrospective and observational study. SETTING Single large university hospital. PARTICIPANTS The study comprised 1,099 adult patients who underwent cardiovascular surgeries with cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS Baseline clinical parameters including platelet counts, the N/L ratio, and the N/LP ratio measured before surgery, immediately after surgery, and on postoperative days 1 and 2 were obtained. Multivariable analysis revealed that the maximal N/LP ratio was an independent predictor of AKI and 5-year mortality. Propensity score matching was performed between the high and low preoperative N/LP ratio groups. Significant differences in the mortality rate and incidence of AKI also were found in the matched cohort. The area under the receiver operating characteristic curve (AUC) of the maximal N/LP ratio as a continuous variable was significantly higher than the AUC of the maximal N/L ratio or nadir platelet as continuous variables (maximal N/LP ratio: 0.62 v N/L ratio: 0.59; p = 0.026 v platelet nadir: 0.57; p = 0.003). The AUC of multivariable risk prediction with the maximal N/LP ratio (0.77) was significantly higher than the AUC without the N/LP ratio (0.70; p < 0.0001). CONCLUSIONS High N/LP ratios were associated with postoperative AKI and 5-year mortality. The N/LP ratio may assist with the the prediction of AKI and mortality in high-risk cardiovascular surgery.

Intraoperative anaphylaxis to neuromuscular blocking agents: the incidence over 9 years at two tertiary hospitals in South Korea: A retrospective observational study.

BACKGROUND Intraoperative anaphylaxis to neuromuscular blocking agents (NMBAs) is a rare event that is unpredictable and potentially life threatening. Most of the previous reports on such intraoperative anaphylaxis used market share surveys or self-reported data to estimate the incidence. OBJECTIVE To determine the incidences of intraoperative anaphylaxis to NMBAs using electronic medical records. DESIGN A retrospective observational study. SETTING Two tertiary hospitals in South Korea. PATIENTS This study involved patients exposed to NMBAs during anaesthesia between 1 January 2005 and 31 May 2014. Nineteen episodes were deemed to be intraoperative anaphylaxis to NMBAs. MAIN OUTCOME MEASURES We calculated the incidences of intraoperative anaphylaxis to NMBAs. Exposure to the agents was determined from intraoperative records maintained in an electronic medical recording system. An anaphylactic reaction was determined from both clinical signs and the results of skin tests. RESULTS Over 9 years, 729 429 patients were exposed to NMBA, the most frequently used being rocuronium [425 047 (58.3%)] and vecuronium [274 801 (37.7%)]. The overall incidence of intraoperative anaphylaxis was 2.6 per 100 000 (19 cases), and was higher with rocuronium (16 cases, 3.8 per 100 000) than with vecuronium (two cases, 0.7 cases per 100 000), P = 0.014. Comparing the first 3 years with the last 6 years, the incidence of intraoperative rocuronium anaphylaxis appeared to increase 1.4-fold (P = 0.006). CONCLUSION Among commonly used NMBAs, rocuronium appears to have the highest incidence of anaphylaxis. Our findings suggest that future prospective investigation for NMBA-induced anaphylaxis should use internationally agreed skin test protocols.

Derivation and Validation of Machine Learning Approaches to Predict Acute Kidney Injury after Cardiac Surgery

Machine learning approaches were introduced for better or comparable predictive ability than statistical analysis to predict postoperative outcomes. We sought to compare the performance of machine learning approaches with that of logistic regression analysis to predict acute kidney injury after cardiac surgery. We retrospectively reviewed 2010 patients who underwent open heart surgery and thoracic aortic surgery. Baseline medical condition, intraoperative anesthesia, and surgery-related data were obtained. The primary outcome was postoperative acute kidney injury (AKI) defined according to the Kidney Disease Improving Global Outcomes criteria. The following machine learning techniques were used: decision tree, random forest, extreme gradient boosting, support vector machine, neural network classifier, and deep learning. The performance of these techniques was compared with that of logistic regression analysis regarding the area under the receiver-operating characteristic curve (AUC). During the first postoperative week, AKI occurred in 770 patients (38.3%). The best performance regarding AUC was achieved by the gradient boosting machine to predict the AKI of all stages (0.78, 95% confidence interval (CI) 0.75–0.80) or stage 2 or 3 AKI. The AUC of logistic regression analysis was 0.69 (95% CI 0.66–0.72). Decision tree, random forest, and support vector machine showed similar performance to logistic regression. In our comprehensive comparison of machine learning approaches with logistic regression analysis, gradient boosting technique showed the best performance with the highest AUC and lower error rate. We developed an Internet–based risk estimator which could be used for real-time processing of patient data to estimate the risk of AKI at the end of surgery.

Effects of preoperative aspirin on perioperative platelet activation and dysfunction in patients undergoing off-pump coronary artery bypass graft surgery: A prospective randomized study

The benefit of aspirin use after coronary artery bypass graft surgery has been well proven. However, the effect of preoperative aspirin use in patients undergoing off-pump coronary artery bypass graft surgery (OPCAB) has not been evaluated sufficiently. To evaluate platelet function changes during OPCAB due to preoperative aspirin use, we conducted a randomized controlled trial using flow cytometry and the Multiplate® analyzer. Forty-eight patients scheduled for elective OPCAB were randomized to the aspirin continuation (100 mg/day until operative day) and discontinuation (4 days before the operative day) groups. Platelet function was measured using the platelet activation markers CD62P, CD63, and PAC-1 by flow cytometry, and platelet aggregation was measured using the Multiplate® analyzer, after the induction of anesthesia (baseline), at the end of the operation, and 24 and 48 h postoperatively. Findings of conventional coagulation assays, thromboelastography by ROTEM® assays, and postoperative bleeding—related clinical outcomes were compared between groups. No significant change in CD62P, CD63, or PAC-1 was observed at the end of the operation or 24 or 48 h postoperatively compared with baseline in either group. The area under the curve for arachidonic acid—stimulated platelet aggregation, measured by the Multiplate® analyzer, was significantly smaller in the aspirin continuation group (P < 0.01). However, chest tube drainage and intraoperative and postoperative transfusion requirements did not differ between groups. Our study showed that preoperative use of aspirin for OPCAB did not affect perioperative platelet activation, but it impaired platelet aggregation, which did not affect postoperative bleeding, by arachidonic acid.