Prediction of preload dependency using phenylephrine-induced peripheral perfusion index during general anaesthesia: a prospective observational study.

BACKGROUND: Tracking preload dependency non-invasively to maintain adequate tissue perfusion in the perioperative period can be challenging.The effect of phenylephrine on stroke volume is dependent upon preload. Changes in stroke volume induced by phenylephrine administration can be used to predict preload dependency. The change in the peripheral perfusion index derived from photoplethysmography signals reportedly corresponds with changes in stroke volume in situations such as body position changes in the operating room. Thus, the peripheral perfusion index can be used as a non-invasive potential alternative to stroke volume to predict preload dependency. Herein, we aimed to determine whether changes in perfusion index induced by the administration of phenylephrine could be used to predict preload dependency. METHODS: We conducted a prospective single-centre observational study. The haemodynamic parameters and perfusion index were recorded before and 1 and 2 min after administering 0.1 mg of phenylephrine during post-induction hypotension in patients scheduled to undergo surgery. Preload dependency was defined as a stroke volume variation of ≥ 12% before phenylephrine administration at a mean arterial pressure of < 65 mmHg. Patients were divided into four groups according to total peripheral resistance and preload dependency. RESULTS: Forty-two patients were included in this study. The stroke volume in patients with preload dependency (n = 23) increased after phenylephrine administration. However, phenylephrine administration did not impact the stroke volume in patients without preload dependency (n = 19). The perfusion index decreased regardless of preload dependency. The changes in the perfusion index after phenylephrine administration exhibited low accuracy for predicting preload dependency. Based on subgroup analysis, patients with high total peripheral resistance tended to exhibit increased stroke volume following phenylephrine administration, which was particularly prominent in patients with high total peripheral resistance and preload dependency. CONCLUSION: The findings of the current study revealed that changes in the perfusion index induced by administering 0.1 mg of phenylephrine could not predict preload dependency. This may be attributed to the different phenylephrine-induced stroke volume patterns observed in patients according to the degree of total peripheral resistance and preload dependency. TRIAL REGISTRATION: University Hospital Medical Information Network (UMIN000049994 on 9/01/2023).

Comparison of Sedation With Ketamine-Propofol Versus Propofol-Fentanyl for Elderly Patients Undergoing Prostate Biopsy: A Retrospective Observational Study.

BACKGROUND: Procedural sedation is increasingly used for elderly patients, but there is no established ideal method for elderly patients who are prone to respiratory and circulatory depression. This study aims to investigate the association of respiratory complications and the combination of ketamine-propofol versus fentanyl-propofol in elderly patients undergoing prostate biopsy requiring deep sedation. METHODS: This was a single-center, retrospective, observational study conducted from April 2020 to March 2021. We included male patients aged 65 years and older scheduled for prostate biopsy under procedural sedation. Ketamine-propofol and fentanyl-propofol were administered at the discretion of the anesthesiologist. The primary outcome was the need for assisted ventilation. The secondary outcome was the duration of oxygen saturation (SpO2) below 90%. RESULTS: We enrolled 120 patients over 65 years, and 92 patients were included in the final analysis. The anesthesiologist administered an initial dose of ketamine and propofol of 1:1 to 1:4 of 1.0 mg kg-1 (interquartile range: 0.98 to 1.17) or administered an initial dose of fentanyl of 0.05 to 0.1 mg and a target-controlled infusion of propofol of 2.8 µg ml-1 (interquartile range: 2.0 to 3.0) followed by additional doses at the discretion of the anesthesiologist. Ketamine-propofol was associated with a reduced need for assisted ventilation and a shorter duration of SpO2 below 90% than propofol-fentanyl (95.7% vs. 4.3%, P < 0.05; 0.64 minutes vs. 0.17 minutes, P = 0.26). CONCLUSIONS: Ketamine-propofol is associated with a significantly reduced need for assisted ventilation compared to propofol-fentanyl during procedural sedation and analgesia for procedures requiring deep sedation for the elderly.

Slower clozapine titration than the official Japanese protocol led to fewer inflammatory adverse effects: A retrospective chart review of seven hospitals.

BACKGROUND: Higher frequencies of inflammatory adverse effects of clozapine have been reported in Japan. As the international titration protocol for Asians has set slower dose titration than the Japanese package insert, we hypothesized that a dose titration speed slower than the recommendation of the guideline would be associated with fewer inflammatory-related adverse events. METHODS: The medical records of all 272 patients who were first started on clozapine at seven hospitals between 2009 and 2023 were studied retrospectively. Of those, 241 were included in the analysis. The patients were divided into two groups regarding whether the titration speed was faster or slower than the guideline for Asians. The incidence of inflammatory adverse events with clozapine was compared between the groups. RESULTS: The frequency of inflammatory adverse events was 34 % (37/110) in the faster titration group and 13 % (17/131) in the slower titration group, and a significant difference was observed by Fisher exact test (odds ratio 3.38; 95 % confidence interval 1.71-6.91; p < 0.001). Serious adverse effects, fever for more than five days, and clozapine discontinuation were significantly more frequent in the faster titration group. Logistic regression analysis indicated significantly more inflammatory adverse events in the faster titration group (adjusted odds ratio 4.01; 95 % confidence interval 2.02-7.87; p < 0.001) considering age, sex, body mass index, concomitant valproic acid, and smoking as confounding factors. CONCLUSION: Clozapine-induced inflammatory adverse events were less frequent in Japanese individuals when a titration rate was more gradual than the protocol recommended in the Japanese package insert.

Characteristics of retained foreign bodies and near-miss events in the operating room: a ten-year experience at one institution.

PURPOSE: Retained foreign bodies (RFBs) are a major complication of surgical procedures. However, the efficacy of preventive measures is not well defined. This study investigates the characteristics of potential (near miss) and actual RFBs, and the contributions of routine practice for the prevention of RFB events. METHODS: We conducted a retrospective review of incident reports regarding near-miss and RFB events in patients who underwent surgery under general anesthesia in our institution between October 2008 and November 2018. RESULTS: Among 49,831 operations under general anesthesia, there were 106 (2.13/1000) near-miss events and 24 (0.48/1000) RFB events. Counting surgical materials and intraoperative X-rays detected the remaining items before completion of surgery in 59 (56%) and 15 (14%) cases, respectively. The operator or staff noticed the surgical materials in the remaining 32 (30%) near-miss events. RFBs included 4 sponges (17%), 4 instruments (17%), 4 needles (17%), and 12 miscellaneous items (50%). Of these, 12 (50%) RFBs were discovered on postoperative X-rays and 16 (67%) patients required operative removal. Four incidents (17%) with RFBs were attributable to ignoring count discrepancies during surgery. CONCLUSION: The actual incidence of RFB events is higher than previously reported. A standardized counting protocol, communication among staff, and intra- and postoperative X-rays may contribute to the prevention and detection of RFBs.

Efficacy of point-of-care thromboelastography 6s to evaluate platelet function in a patient with pseudothrombocytopenia undergoing cardiopulmonary bypass: a case report.

BACKGROUND: Pseudothrombocytopenia is a phenomenon caused by in vitro platelet aggregation induced by anticoagulants contained in blood sampling tubes. Thromboelastography (TEG) 6s is a common point-of-care viscoelastic test to assess intraoperative coagulation status, which may reduce the need for blood transfusions. The reliability and usefulness of TEG6s for patients with pseudothrombocytopenia has not been established. CASE PRESENTATION: We present a patient with pseudothrombocytopenia, who underwent suprarenal abdominal aortic aneurysm repair under cardiopulmonary bypass. At the beginning of surgery, TEG6s with citrated blood sampling showed that the results were unaffected by the disease. After completion of the aortic repair and the administration of protamine, maximum amplitude of TEG6s and adequate hemostasis were achieved without platelet transfusions, while standard laboratory tests showed thrombocytopenia. CONCLUSIONS: In the present patient who underwent cardiopulmonary bypass, TEG6s may have contributed to a reliable and useful assessment of coagulation and hemostatic status avoiding unnecessary platelet transfusions.

Changes in peripheral perfusion index during intraoperative end-expiratory occlusion tests do not predict the response to fluid administration in patients undergoing lung protective ventilation.

INTRODUCTION: The end-expiratory occlusion test (EEOT) may predict the response to fluid administration in patients undergoing lung-protective ventilation, but arterial catheter insertion is necessary to evaluate changes in stroke volume (SV). The peripheral perfusion index is a potential noninvasive alternative to evaluate SV. The aim of this study is to investigate whether changes in perfusion index during an intraoperative EEOT can predict the response to fluid administration in patients undergoing lung-protective ventilation (tidal volume 7 ml/kg predicted body weight). METHODS: Forty-one elective surgical patients were enrolled. The SV and perfusion index were recorded before (baseline), during a 40-s EEOT and after volume expansion (250 ml of lactated Ringer's solution over 10 min). Patients with an increase in SV greater than 10% after volume expansion were defined as responders. ΔPI (change in perfusion index between baseline and 20 (ΔPI20) or 40 s (ΔPI40) after the beginning of EEOT were calculated using: ΔPI20 (%) = [(PI at 20 s after EEOT beginning - PIbaseline)/PIbaseline] × 100, ΔPI40 (%) = [(PI at 40 s after EEO beginning - PIbaseline)/PIbaseline] × 100). RESULTS: Sixteen patients were responders, and 25 were non-responders. The area under the receiver operating characteristics curves generated for ΔPI20 and ΔPI40 to predict response to a fluid challenge were 0.561 (95% CI 0.374-0.749) and 0.688 (95% CI 0.523-0.852), respectively. CONCLUSION: Changes in perfusion index during intraoperative EEOT in patients undergoing lung-protective ventilation (7 ml/kg) were unable to predict the response to fluid administration.

Correlation between activated clotting time monitoring and heparin concentration measurement in a patient with antiphospholipid syndrome during cardiac valve surgery: a case report.

BACKGROUND: Anticoagulation management of patients with antiphospholipid syndrome (APS) undergoing cardiac surgery is challenging due to the prolongation of activated clotting time (ACT). Currently, no study has compared the utility of ACT monitoring using the Hemochron Jr. Signature+ and that of heparin concentration management using the Hemostasis Management System (HMS) Plus in patients with APS. CASE PRESENTATION: A 71-year-old woman with APS was scheduled to undergo an aortic valve replacement for aortic regurgitation. The ACT was measured using the Hemochron Jr. Signature+, and the heparin concentration was measured concurrently using the HMS Plus. ACT over 480 s corresponded to an adequate heparin concentration during cardiopulmonary bypass. The clinical course was uneventful, and no thrombotic or hemorrhagic complications were observed. CONCLUSION: In the present patient with APS, the Hemochron Jr. Signature+ was useful as an anticoagulation management during cardiac valve surgery.

Autonomous oil flow generated by self-oscillating polymer gels.

The previously reported gel and polymer actuators require external inputs, such as batteries, circuits, electronic circuits, etc., compared with autonomous motions produced by the living organisms. To realize the spontaneous motions, here, we propose to integrate a power supply, actuators, and control into a single-component self-oscillating hydrogel. We demonstrate self-actuating gel pumps driven by the oscillatory Belousov-Zhabotinsky (BZ) reaction without electronic components. We have developed the volume oscillation of gels synchronized with the BZ reaction (BZ gel). Since the self-actuating gel pumps are driven by chemo-mechanical energy from BZ gels, the self-actuating gel pumps don't require complex wiring designs, energy supply, and assembling. The mechanical work generated by BZ gels is extremely small. We formulated the thermodynamic cycle of BZ gels and maximized mechanical work. We found that pre-stretched BZ gel shows larger mechanical works. We physically separated the BZ gels and working fluid to create practical pumps. By using optimizing mechanical generated by BZ gels, we demonstrated the self-actuating gel pumps that transfer mechanical work through a stretchable elastomer membrane.

Selective oxidation of B800 bacteriochlorophyll a in photosynthetic light-harvesting protein LH2.

Engineering chlorophyll (Chl) pigments that are bound to photosynthetic light-harvesting proteins is one promising strategy to regulate spectral coverage for photon capture and to improve the photosynthetic efficiency of these proteins. Conversion from the bacteriochlorophyll (BChl) skeleton (7,8,17,18-tetrahydroporphyrin) to the Chl skeleton (17,18-dihydroporphyrin) produces the most drastic change of the spectral range of absorption by light-harvesting proteins. We demonstrated in situ selective oxidation of B800 BChl a in light-harvesting protein LH2 from a purple bacterium Rhodoblastus acidophilus by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. The newly formed pigment, 3-acetyl Chl a, interacted with the LH2 polypeptides in the same manner as native B800. B850 BChl a was not oxidized in this reaction. CD spectroscopy indicated that the B850 orientation and the content of the α-helices were unchanged by the B800 oxidation. The nonameric circular arrangement of the oxidized LH2 protein was visualized by AFM; its diameter was almost the same as that of native LH2. The in situ oxidation of B800 BChl a in LH2 protein with no structural change will be useful not only for manipulation of the photofunctional properties of photosynthetic pigment-protein complexes but also for understanding the substitution of BChl to Chl pigments in the evolution from bacterial to oxygenic photosynthesis.

Acute cerebral infarction in a patient with an epidural catheter after left upper lobectomy: a case report.

BACKGROUND: There are several recent reports that left upper lobe lung resection is a risk factor for the development of postoperative thromboembolism. Although administering epidural analgesia is common in thoracic surgery, anesthesiologists should be alert when administering epidural analgesia to a patient undergoing left upper lobectomy, considering the increased risk of postoperative thromboembolism and the potential need for anticoagulation or fibrinolytic therapy in the immediate postoperative period. CASE PRESENTATION: A seventy-one-year-old female with a metastatic lung lesion developed a cerebral infarction approximately 30 h after video-assisted thoracoscopic left upper lobectomy. Cerebral intravascular therapy was indicated and the epidural catheter was removed immediately to avoid formation of an epidural hematoma. Approximately four hours after onset, reperfusion was successfully established by aspiration of endovascular thrombi. She recovered with mild residual paralysis of the left upper extremity and was transferred to a rehabilitation facility. CONCLUSIONS: We present a patient with a cerebral infarction after left upper lobectomy. Left upper lobectomy is associated with an increased risk of postoperative thromboembolism. Although the exact mechanism of thrombosis after left upper lobectomy is unclear, a judicious decision should be made regarding epidural catheter placement for postoperative analgesia.

Wide discrepancies in activated clotting times measured by two devices were detected for a patient with lupus anticoagulant in a cardiac surgery.

INTRODUCTION:: For a patient with lupus anticoagulant (LA), activated coagulation time (ACT) was measured with two different types of devices (HEMOCHRON® 801 and HEMOCHRON® Jr). CASE REPORT:: ACTs during heparinization measured with the HEMOCHRON® 801 were over the range of measurement, while those with the HEMOCHRON® Jr. reflected an almost normal response to heparin. DISCUSSION:: The phospholipid contained in an activating agent of the HEMOCHRON® Jr was suggested to have counteracted the effect of LA. CONCLUSION:: It was indicated that the coagulation status for LA-positive patients might be better assessed by ACT measured with phospholipid in an activating agent, although careful interpretation is required.

Landiolol infusion during general anesthesia does not prevent postoperative atrial fibrillation in patients undergoing lung resection.

OBJECTIVE: We aimed to determine whether intraoperative low-dose infusion of landiolol, an ultra-short-acting beta blocker, can prevent postoperative atrial fibrillation (POAF) after lung resection. METHODS: A double-blind, randomized, controlled, preliminary study was performed in university academic hospital, single center. Fifty lung surgical patients were key-opened before enrollment of the originally planned 100 patients, who were randomized in a 1:1 ratio in each treatment arm. Landiolol was infused with a dosage of 5 µg/kg/min during general anesthesia in the landiolol group, which was compared with the placebo control group with no landiolol. Atrial fibrillation (AF)-free survival curves were generated by means of Kaplan-Meier estimates and differences in survival were compared with the use of the log-rank test. We examined independent predictors of POAF by the multivariate logistic regression analysis using the perioperative parameters detected with the univariate analysis. RESULTS: The AF events were recorded for 7 days with Holter monitor in 5 of 25 patients in the landiolol group and 4 of 25 patients in the control group. Kaplan-Meier analysis showed that the landiolol group could not avoid the incidence of POAF in comparison with the placebo saline group (P = 0.806). The multivariate logistic regression analysis for prevalence of POAF identified only one statistically significant predictor: interleukin-6 (IL-6) sampled at 6 h after end of surgery. CONCLUSIONS: We failed to demonstrate that low-dose infusion of landiolol during general anesthesia could prevent the incidence of AF after lung resection. Only IL-6 sampled at 6 h after end of surgery significantly predicted POAF among pulmonary surgical patients.

Uptake of a fluorescent L-glucose derivative 2-NBDLG into three-dimensionally accumulating insulinoma cells in a phloretin-sensitive manner.

Of two stereoisomers of glucose, only D- and not L-glucose is abundantly found in nature, being utilized as an essential fuel by most organisms. The uptake of D-glucose into mammalian cells occurs through glucose transporters such as GLUTs, and this process has been effectively monitored by a fluorescent D-glucose derivative 2-[N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG) at the single cell level. However, since fluorescence is an arbitrary measure, we have developed a fluorescent analog of L-glucose 2-[N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-L-glucose (2-NBDLG), as a negative control substrate for more accurately identifying the stereoselectivity of the uptake. Interestingly, a small portion of mouse insulinoma cells MIN6 abundantly took up 2-NBDLG at a late culture stage (≳ 10 days in vitro, DIV) when multi-cellular spheroids exhibiting heterogeneous nuclei were formed, whereas no such uptake was detected at an early culture stage (≲ 6 DIV). The 2-NBDLG uptake was persistently observed in the presence of a GLUT inhibitor cytochalasin B. Neither D- nor L-glucose in 50 mM abolished the uptake. No significant inhibition was detected by inactivating sodium/glucose cotransporters (SGLTs) with Na(+)-free condition. To our surprise, the 2-NBDLG uptake was totally inhibited by phloretin, a broad spectrum inhibitor against transporters/channels including GLUTs and aquaporins. From these, a question might be raised if non-GLUT/non-SGLT pathways participate in the 2-NBDLG uptake into spheroid-forming MIN6 insulinoma. It might also be worthwhile investigating whether 2-NBDLG can be used as a functional probe for detecting cancer, since the nuclear heterogeneity is among critical features of malignancy.

Intracranial hemorrhage associated with cerebrospinal fluid drainage during thoraco-abdominal aortic surgery.

A 69-year-old woman underwent thoraco-abdominal aortic aneurysm repair with cerebrospinal fluid drainage (CSFD). The initial CSF pressure was elevated to approximately 25 cmH(2)O, and clear CSF was continuously drained at a rate of 30 ml/h with the drainage level at 10-20 cmH(2)O. The CSF became bloody when cardiopulmonary bypass was terminated. The total volume of CSF drained was approximately 300 ml at the conclusion of the 638 min operation. Three hours later, she suffered a series of generalized seizures because of intracranial hemorrhage (ICH). It was suggested that excessive drainage of CSF was associated with ICH. Meticulous control of drainage volume combined with standard pressure-based management may be the key to avoiding these complications.

Energy-loss near-edge structure (ELNES) and first-principles calculation of electronic structure of nickel silicide systems.

The electronic structures of nanometre-sized nickel silicide systems, Ni(2)Si and NiSi, have been studied by energy-loss near-edge structure (ELNES) and first-principles band structure calculations. Experimental ELNES of Ni L(3)- and Si L(2,3)-edges could be explained well using theoretical spectra calculated for the ground state without the core hole, suggesting metallic properties for both silicides. It was shown that a slight difference in ELNES spectra of Ni(2)Si and NiSi comes from the coupling among the Ni d and Si p, d states in the unoccupied bands. The density of states and the contour plots of all the valence electron densities for Ni(2)Si, NiSi together with NiSi(2) show that Ni(2)Si has the bond with the strongest covalent character between Ni and Si atoms and the most transition metal-like character of the Ni 3d band among the three silicides.

[Successful airway management using a Cook airway exchange catheter as an emergent dilator for life-threatening neoplastic stenosis of the trachea: a case report].

A 68-year-old male patient was referred to our hospital for his intractable and progressive dyspnea. Chest roentgenography and computerized tomography revealed severe lower tracheal stenosis due to neoplastic invasion. The tumor completely surrounded his trachea for 5 cm length and the remaining internal diameter of the trachea was less than 5 mm. To avoid fatal asphyxia, emergency airway security was required. After placing both femoral arterial and venous cannulae for percutaneous cardiopulmonary support system, we dilated the stenotic trachea using a Cook airway exchange catheter (CAEC), and then an armored tube of 7 mm inner diameter was introduced through the CAEC. The maneuver was smoothly completed within one minute without any complications. His dyspnea was completely relieved. Following chemotherapy and radiotherapy were so effective that the endotracheal tube was extubated two weeks later uneventfully. After several series of chemotherapy and 50 Gy irradiation, the patient was discharged three months later without symptoms. We concluded that CAEC could be one of the life-saving instruments for emergent airway management in case of severe organic tracheal stenosis.