Atrial Fibrillation is related with higher in-hospital morality in acute myocardial infarction (AMI) patients from K-ACTIVE registry

Background

The prognostic significance of atrial fibrillation (AF) on in-hospital mortality in acute myocardial infarction (AMI) patients is not fully understood in Japanese patients.

Methods

To elucidate the clinical significance of AF on in-hospital mortality in AMI patients, we analyzed the Japanese observational prospective multicenter registry of acute myocardial infarction (K-ACTIVE: Kanagawa ACuTe cardio Vacular rEgistry), which spans October 2016 to December 2019.

Results

A total of 3482 patients included 336 patients with AF and 3146 patients with sinus rhythm. Table 1 shows patient baseline characteristics. Patients with AF were significantly older than those with sinus rhythm (75 vs 67, P<0.0001). Prevalence of hypertension and hemodialysis were significantly greater in patients with AF than patients with sinus rhythm while prevalence of dyslipidemia and smoking were significantly less in patients with AF than patients with sinus rhythm. Table 2 shows characteristics of AMI. There were no significant difference in prevalence of STEMI, area of MI, Peak CK/CK-MB and prevalence of multivessel disease. However, patients with AF showed lower systolic blood pressure, faster heart rate, worse Killip category, greater prevalence of OHCA. Need of mechanical support including IABP/ECMO were greater in patients with AF than patients with sinus rhythm. In-hospital mortality was significantly higher in patients with AF than in patients with sinus rhythm (Figure, 10.4% versus 5.2%, P=0.0005). This trend didn't change even after adjustment with age and sex (Odds ratio 1.6 95% confidence interval 1.1–2.4, P=0.02).

Conclusion

AF was associated with higher in-hospital mortality in Japanese AMI patients.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This work was supported by JSPS KAKENHI Grant Number JP15K09101.

P17 In-hospital mortality and clinical features of Japanese patients with acute myocardial infarction diagnosed by universal definition in real world from kanagawa-acute cardiovascular registry (K-ACTIVE)

Background

Cardiac troponin (cTn) has been used as the preferred biomarker of myocardial injury for diagnosis of acute myocardial infraction (AMI) by universal definition. A large number of patients formerly classified by creatine kinase (CK) as unstable angina with the WHO criteria in Japan are now diagnosed by cTn as non-ST elevation myocardial infarction (NSTEMI). In this report, we aimed to understand its prevalence and clinical features of AMI diagnosed by using universal definition and the WHO criterial in real world. 

Method

This registry is a cross-sectional study of 53 facilities in Kanagawa prefecture of Japan. 4372 AMI patients were enrolled who received primary percutaneous coronary intervention (PCI) between October 1, 2015 and January 29, 2019. Patients were divided into 3 groups, 3268 patients with ST elevation myocardial infarction (STEMI), 628 patients with NSTEMI patients who satisfied the WHO criteria with CK elevation beyond twice upper limit of normal (NSTEMI + CK), and 476 patients with NSTEMI who didn’t satisfy the WHO criteria without CK elevation (NSTEMI-CK).

Result

Baseline clinical characteristics of the study patients are shown in Table 1. In-hospital mortality was significantly lower in patients with NSTEMI-CK (1.9%) than in STEMI (6.0%, P < 0.001) and NSTEMI + CK (5.3%, P < 0.004) (Figure 1). Kaplan-Meier analyses for 0-30 days of cardiac death are shown in Figure 2. From day 0, the Kaplan-Meier curves began to diverge in favor of NSTEMI-CK for up to 30 days.

Conclusion

AMI patients showed distinct clinical features depends on the type. We should be aware of the difference for the diagnosis of AMI by using universal definitions.

Table 1. 　 STEMI (n = 3268) NSTEMI + CK (n = 628) NSTEMI-CK (n = 476) STEMI vs NSTEMI + CK P value STEMI vs NSTEMI-CK P value NSTEMI + CK vs NSTEMI-CK P value Age(years) 68(59-77) 69(61-78) 70(61-79) 　 　 　 Male 76% 77% 75% 0.54 0.74 0.47 Concomitant diseases 　 　 　 　 　 　 Hypertention 65.4% 70.5% 69.3% 0.013 0.097 0.65 Diabetes 33.5% 36.5% 37.3% 0.15 0.11 0.78 Dyslipidemia 56.1% 61.2% 61.3% 0.018 0.03 0.96 Hemodialysis 2.3% 2.1% 6.8% 0.86 <0.001 0.01 Smoking 66.3% 63.1% 64.6% 0.13 0.48 0.62 Atrial fibrillation 9.6% 10.7% 14.4% 0.57 0.04 0.23 Previous MI 8.3% 17.3% 15.7% <0.001 <0.001 0.47 In-hospital mortality 6.0% 5.3% 1.9% 0.49 <0.001 0.004

Abstract P17 Figure 1. 2.

Cyclic lava effusion during the 2018 eruption of Kīlauea Volcano

Lava flows present a recurring threat to communities on active volcanoes, and volumetric eruption rate is one of the primary factors controlling flow behavior and hazard. The time scales and driving forces of eruption rate variability, however, remain poorly understood. In 2018, a highly destructive eruption occurred on the lower flank of Kīlauea Volcano, Hawai‘i, where the primary vent exhibited substantial cyclic eruption rates on both short (minutes) and long (tens of hours) time scales. We used multiparameter data to show that the short cycles were driven by shallow outgassing, whereas longer cycles were pressure-driven surges in magma supply triggered by summit caldera collapse events 40 kilometers upslope. The results provide a clear link between eruption rate fluctuations and their driving processes in the magmatic system.

Adenosine and adenosine uptake inhibitors potentiate the neuromuscular blocking action of rocuronium mediated by adenosine A(1) receptors in isolated rat diaphragms

BACKGROUND

Adenosine, which pre-junctionally modulates neuromuscular transmission, and adenosine uptake inhibitors, which increase extracellular adenosine, have been used clinically. We investigated the effects of adenosine, dipyridamole and midazolam on the neuromuscular blocking action of rocuronium.

METHODS

Isometric twitch tensions of rat nerve-hemidiaphragm preparations elicited by indirect (phrenic nerve) supra-maximal stimulation at 0.1 Hz were evaluated (n=6 in all data).

RESULTS

Pre-treatments with adenosine (0.1 and 1 microM) and CCPA (1 microM, adenosine A(1) receptor agonist), but not that with CGS21680 (0.5 microM, A(2) receptor agonist), shifted the rocuronium concentration-twitch tension curves to the left and decreased the rocuronium concentration for 50% twitch depression (IC(50)) compared with the control (P<0.01). The leftward shift induced by 1 microM adenosine was inhibited by pre-treatments with theophylline (50 microM, non-selective adenosine receptor antagonist) and DPCPX (0.2 microM, A(1) receptor antagonist) but not by that with DPMA (5 microM, A(2) receptor antagonist). Pre-treatments with dipyridamole and midazolam, adenosine uptake inhibitors, shifted the curve to the left and decreased IC(50) at supra-therapeutic concentrations (10 and 2.5 microM, respectively) but not at clinical concentrations (2 and 0.5 microM, respectively), and the leftward shifts were inhibited by pre-treatment with DPCPX (0.2 microM).

CONCLUSION

The results indicate that adenosine potentiates the neuromuscular blocking action of rocuronium mediated by adenosine A(1) receptors and that supra-therapeutic concentrations of dipyridamole and midazolam also potentiate the action of rocuronium by increasing endogenous adenosine concentration.

Propofol attenuates ischaemia-reperfusion injury in the rat heart in vivo

BACKGROUND

We have previously demonstrated, in the isolated rat heart, that propofol attenuates hydrogen peroxide-induced damage and ischaemia-reperfusion injury, and that the beneficial effect of propofol is correlated with reduction of the lipid peroxidation. This study was designed to evaluate whether propofol has a cardioprotective effect against ischaemia-reperfusion injury in a rat model in vivo.

METHODS

Adult rats were anaesthetized with pentobarbital 10 mg kg(-1) h(-1) alone (control group), pentobarbital 10 or 20 mg kg(-1) h(-1) + Intralipid as a vehicle (Pent-10, Pent-20 group), propofol 10 or 20 mg kg(-1) h(-1) (Prop-10, Prop-20 group) intravenously throughout the experiment. The left anterior descending coronary artery was occluded for 30 min followed by 120 min of reperfusion. Infarct size was determined at the end of reperfusion. The tissue concentration of malondialdehyde was measured at 30 min after reperfusion to evaluate lipid peroxidation.

RESULTS

The infarct sizes (% of area at risk) were significantly smaller in the Prop-10 (54 +/- 11%; P < 0.01 vs. control) and Prop-20 (39 +/- 8%; P < 0.01 vs. control) groups than in the control (68 +/- 9%), Pent-10 (69 +/- 13%) and Pent-20 (68 +/- 14%) groups (n = 12). In the Pent-10 and Pent-20 groups, ischaemia-reperfusion produced significant increases in the values for tissue malondialdehyde (0.72 +/- 0.24 micromol mg protein-1; P < 0.05 and 0.63 +/- 0.33 micromol mg protein-1; P < 0.05 vs. 0.46 +/- 0.22 micromol mg protein-1 in non-ischaemic hearts, n = 8). However, the values of malondialdehyde in the Prop-10 and -20 groups were suppressed by 41% and 63%, respectively, compared with the Pent-10 group (P < 0.01).

CONCLUSION

Our results suggest that propofol could be cardioprotective against ischaemia-reperfusion injury dose dependently in a rat model in vivo and that the beneficial action of propofol may be correlated with its antioxidant effect.

Inhibitory effects of the alpha-2 adrenergic agonists clonidine and dexmedetomidine on enhanced airway tone in ovalbumin-sensitized guinea pigs

BACKGROUND AND OBJECTIVE

The alpha-2 adrenergic agonists clonidine and dexmedetomidine are used as an antihypertensive and a sedative, respectively. The aim of this study was to determine the effects of these agonists on ovalbumin-sensitized airway tone in guinea pigs.

METHODS

The animals were divided into two groups: control and sensitized. The sensitized group received ovalbumin intraperitoneally and was boosted by exposure to aerosolized ovalbumin. The effects of the alpha-2 agonists were investigated by measuring (1) total lung resistance and (2) smooth muscle tension using a tracheal ring preparation.

RESULTS

In the control group, acetylcholine significantly increased total lung resistance in a dose-dependent manner. In the sensitized animals, total lung resistance was significantly higher (by 95%) at 6 mug kg-1 acetylcholine than that in the control group. Both clonidine and dexmedetomidine had a slight but significant inhibitory effect on the response curve of lung resistance at higher concentrations of carbachol, a potent muscarinic receptor agonist. Similar to the data obtained in the control group, both clonidine and dexmedetomidine significantly decreased total lung resistance and the inhibitory effects of these alpha-2 agonists on lung resistance were significantly distinguishable. Similar direct inhibitory effects of the alpha-2 agonists on carbachol-induced muscle contraction were observed in both the control and sensitized groups, the inhibitory effects in the sensitized group being significantly greater.

CONCLUSION

Both clonidine and dexmedetomidine can relax the airway even in the hyper-reactive state.

Analysis of the composition of 'original' and generic sevoflurane in routine use

BACKGROUND

Original sevoflurane (Sevofrane) contains a small amount of water, which can inhibit the production of hydrofluoric acid. Hydrofluoric acid is highly pungent, and sevoflurane that contains a high concentration of hydrofluoric acid is not suitable for volatile induction of anaesthesia. Recently, generic sevoflurane (Sevoness) has become available in some countries. The generic product is produced by a different method and kept in a different kind of bottle. We questioned whether the original and generic sevoflurane differed in their composition and thus might differ in their resistance to degradation.

METHODS

Sevoflurane from groups of three bottles of Sevofrane and three bottles of Sevoness was kept in the bottle at 24-37 degrees C for 2 weeks or in two kinds of vaporizer for 3 days, and the resulting contents measured by gas chromatography.

RESULTS

Both products contained sevoflurane concentrations exceeding 99.998%. Fluoride ion concentration did not differ between the products (0.043 ppm). The original sevoflurane contained more (0.07% w/v) water than the generic anaesthetic (0.003% w/v). Original sevoflurane contained 5 ppm compound A, 10 ppm sevomethylether, and 5 ppm of unknown materials. Generic sevoflurane contained 32 ppm hexafluoroisopropanol and 12 ppm of unknown materials. While stored in a vaporizer for 3 days, the water content in the original sevoflurane decreased by two-thirds but the water in the generic sevoflurane increased by a factor of three-fold.

CONCLUSIONS

Generic sevoflurane contains high-quality sevoflurane and only a small amount of fluoride ions, making it comparable with the original sevoflurane product.

Bone cancer increases transient receptor potential vanilloid subfamily 1 expression within distinct subpopulations of dorsal root ganglion neurons

Bone cancer pain has a strong impact on the quality of life of patients but is difficult to treat. Therefore, the mechanisms of bone cancer pain require elucidation for the purpose of development of new therapeutics. A recent study showed that activation of transient receptor potential vanilloid subfamily 1 (TRPV1) was involved in bone cancer pain. In this study, we re-evaluated the analgesic effects of pharmacological blockade of TRPV1 using the potent TRPV1 antagonist 5-iodoresiniferatoxin (I-RTX) and examined whether bone cancer can change TRPV1 expression and distribution in the primary sensory neurons in a mouse model of bone cancer pain. Implantation of osteosarcoma into the femur induced ongoing and movement-evoked bone cancer-related pain behaviors. These behaviors were significantly reduced by i.p. administration of I-RTX, compared with vehicle. Western blot and reverse transcription-polymerase chain reaction (RT-PCR) analyses revealed that TRPV1 level was significantly increased in dorsal root ganglions (DRGs) ipsilateral to sarcoma implantation. Immunohistochemical analysis showed that implantation of osteosarcoma induced not only an increase in the percentage of TRPV1-positive neurons among DRG neurons (24.3+/-1.3% in sham mice and 31.2+/-1.3% in mice with osteosarcoma implantation, P<0.05) but also an overall shift in the distribution of area of profiles to the right. Colocalization study showed that the percentages of colocalization of TRPV1 with neurofilament 200 kD (NF200) and calcitonin gene-related peptide (CGRP) but not isolectin B4 (IB4) among DRG neurons in mice with osteosarcoma implantation were increased compared with those in sham mice (from 0.8+/-0.1% to 2.1+/-0.3% for TRPV1 and NF200 and from 21.1+/-1.3% to 26.5+/-0.2% for TRPV1 and CGRP). In conclusion, TRPV1 activation plays a critical role in the generation of bone cancer pain, and bone cancer increases TRPV1 expression within distinct subpopulation of DRG neurons. These findings may lead to novel strategies for the treatment of bone cancer pain.

Immunohistochemical analysis of acid-sensing ion channel 2 expression in rat dorsal root ganglion and effects of axotomy

Several studies have suggested that acid-sensing ion channel 2 (ASIC2) plays a role in mechanoperception and acid sensing in the peripheral nervous system. We examined the expression and distribution of ASIC2 in the rat dorsal root ganglion, the co-localization of ASIC2 with tropomyosin-related kinase (trk) receptors, and the effects of axotomy on ASIC2 expression. ASIC2 immunoreactivity was observed in both neurons and satellite cells. ASIC2-positive neurons accounted for 16.5 +/- 2.4% of the total neurons in normal dorsal root ganglion. Most ASIC2-positive neurons were medium-to-large neurons and were labeled with neurofilament 200 kD (NF200). Within these neurons, ASIC2 was not evenly distributed throughout the cytoplasm, but rather was accumulated prominently in the cytoplasm adjacent to the axon hillock and axonal process. We next examined the co-localization of ASIC2 with trk receptors. trkA was expressed in few ASIC2-positive neurons, and trkB and trkC were observed in 85.2% and 53.4% of ASIC2-positive neurons, respectively, while only 6.9% of ASIC2-positive neurons were co-localized with trkC alone. Peripheral axotomy markedly reduced ASIC2 expression in the axotomized dorsal root ganglion neurons. On the other hand, intense ASIC2 staining was observed in satellite cells. These results show that ASIC2 is expressed in the distinct neurochemical population of sensory neurons as well as satellite cells, and that peripheral axotomy induced marked reductions in ASIC2 in neurons.

Effects of thiopental on bispectral index and heart rate variability

BACKGROUND AND OBJECTIVE

Thiopental has been reported to reduce sympathetic tone, however, it is not clear whether change in heart rate variability is associated with depth of anaesthesia. The purpose of the present study was to evaluate changes in heart rate variability at different depths of hypnosis during induction of anaesthesia with thiopental.

METHODS

We studied 17 ASA I patients scheduled for minor surgery. The depth of hypnosis was monitored by the BIS. Spectral analysis of heart rate variability using a maximum entropy method resulted in a characteristic power spectrum with two main regions, a high frequency and a low frequency. Haemodynamics, entropy, low frequency, high frequency and low frequency/high frequency were monitored in an awake state and after the induction of anaesthesia.

RESULTS

Heart rate increased in a BIS-dependent manner, whereas blood pressure showed no significant changes during the study period. High frequency, entropy and low frequency decreased with a reduction in the BIS value. Low frequency/high frequency showed no significant change during the study period.

CONCLUSIONS

Induction of anaesthesia with thiopental increased heart rate and decreased high frequency, entropy and low frequency in a BIS-dependent manner, indicating that thiopental reduces cardiac parasympathetic tone depending on the depth of hypnosis.

Performance of three systems for warming intravenous fluids at different flow rates

This study compared the intravenous fluid warming capabilities of three systems at different flow rates. The devices studied were a water-bath warmer, a dry-heat plate warmer, and an intravenous fluid tube warmer Ambient temperature was controlled at 22 degrees to 24 degrees C. Normal saline (0.9% NaCl) at either room temperature (21 degrees to 23 degrees C) or at ice-cold temperature (3 degrees to 5 degrees C) was administered through each device at a range of flow rates (2 to 100 ml/min). To mimic clinical conditions, the temperature of the fluid was measured with thermocouples at the end of a one metre tube connected to the outflow of the warmer for the first two devices and at the end of the 1.2 m warming tubing for the intravenous fluid tube warmer The temperature of fluid delivered by the water bath warmer increased as the flow rate was increased up to 15 to 20 ml/min but decreased with greater flow rates. The temperature of the fluid delivered by the dry-heat plate warmer significantly increased as the flow rate was increased within the range tested (due to decreased cooling after leaving the device at higher flow rates). The temperature of fluid delivered by the intravenous fluid tube warmer did not depend on the flow rate up to 20 ml/min but significantly and fluid temperature-dependently decreased at higher flow rates (>30 ml/min). Under the conditions of our testing, the dry heat plate warmer delivered the highest temperature fluid at high flow rates.

Angular distributions of H-induced HD and D2 desorptions from the Si(100) surfaces

We measured angular distributions of HD and D2 molecules desorbed via the reactions H+DSi(100)-->HD [abstraction (ABS)] and H+DSi(100)-->D2 [adsorption-induced-desorption (AID)], respectively. It was found that the angular distribution of HD molecules desorbed along ABS is broader than that of D2 molecules desorbed along AID, i.e., the former could be fit with cos(2.0+/-0.2) theta, while the latter with cos(5.0+/-0.5) theta. This difference of the angular distributions between the two reaction paths suggests that their dynamic mechanisms are different. The observed cos2 theta distribution for the ABS reaction was reproduced by the classical trajectory calculations over the London-Eyring-Polanyi-Sato potential-energy surfaces. The simulation suggests that the HD desorption along the ABS path takes place along the direction of Si-D bonds, but the apparent angular distribution is comprised of multiple components reflecting the different orientations of D-occupied Si dimers in the (2 x 1) and (1 x 2) double domain structures.

Use of percutaneous cardiopulmonary support in catastrophic massive pulmonary fat embolism

We report a patient who sustained massive catastrophic pulmonary fat embolism while undergoing surgery for intramedullary nail of femur. Application of percutaneous cardiopulmonary support, in our view, saved the patient from cardiopulmonary collapse.

Desorption dynamics of deuterium molecules from the Si(100)-(3x1) dideuteride surface

We measured polar angle (theta)-resolved time-of-flight spectra of D2 molecules desorbing from the Si(100)-(3x1) dideuteride surface. The desorbing D2 molecules exhibit a considerable translational heating with mean desorption kinetic energies of approximately 0.25 eV, which is mostly independent of the desorption angles for 0 degrees<or=theta<or=30 degrees. The observed desorption dynamics of deuterium was discussed along the principle of detailed balance to predict their adsorption dynamics onto the monohydride Si surface.

Endothelin-1 enhances capsaicin-evoked intracellular Ca2+ response via activation of endothelin a receptor in a protein kinase Cε-dependent manner in dorsal root ganglion neurons

Increasing evidence indicates that endothelin-1 has a role for peripheral nociceptive signaling in animals and humans. However, the mechanisms of the nociceptive effects of endothelin-1 have not been fully understood. The current study investigated the effects of endothelin-1 on the capsaicin-evoked intracellular Ca2+ response of cultured adult mice dorsal root ganglion neurons. Dorsal root ganglia were harvested from adult male C57B6N mice and were cultured. With a digital image analysis system, we detected the [Ca2+]i image of cultured dorsal root ganglion cells after loading with Fura-2 acetoxymethyl. In addition, co-localization of protein kinase Cepsilon with transient receptor potential V1 and the translocation of protein kinase Cepsilon were investigated using immunohistochemical methods. Endothelin-1 (10 nM) enhanced an increase in [Ca2+]i by capsaicin (10 nM) from 87.6+/-11.6 nM to 414.8+/-62.3 nM (71 of 156 neurons). The inhibition of endothelin A receptor (BQ-123) significantly suppressed the enhancing effect of endothelin-1. In addition, a nonselective protein kinase C inhibitor (bisindolylmaleimide I) significantly suppressed the enhancing effect of endothelin-1. A myristoyl-tagged membrane-permeant-protein kinase Cepsilon V1-2 inhibitory peptide also significantly suppressed the enhancing effect of endothelin-1. In the immunocytochemical study, protein kinase Cepsilon immunoreactivity was found in most of transient receptor potential V1-positive neurons. After endothelin-1 application, protein kinase Cepsilon immunoreactivity was observed to be translocated from the cytosol to the cell membrane in transient receptor potential V1-positive neurons. Our results indicate that endothelin-1 enhances the response of dorsal root ganglion neurons to capsaicin in a protein kinase Cepsilon-dependent manner. Our findings may lead to a new strategy to treat pain associated with endothelin-1.

Comparative study between propofol in a long-chain triglyceride and propofol in a medium/long-chain triglyceride during sedation with target-controlled infusion

This study was performed to compare the pharmacological characteristics of propofol in an emulsion of both medium- and long-chain triglycerides (MCT/LCT) with those of propofol in an LCT emulsion, by measuring the sedative level and the plasma concentration of propofol during sedation using a target-controlled infusion (TCI) technique. Forty ASA 1 or 2 adult patients who required spinal anaesthesia for surgery were enrolled in this study. The patients were divided into two groups: a propofol LCT group (n = 20) and a propofol MCT/LCT group (n = 20). Propofol was injected intravenously at target blood concentrations of 2.0, 3.0 and 4.0 microg x ml(-1). The bispectral (BIS) index was recorded, and arterial blood was drawn to measure the actual plasma concentrations of propofol at each predicted concentration. Propofol was assayed by high-performance liquid chromatography. Propofol MCT/LCT was associated with significantly less pain than propofol LCT (P < 0.05). There were no significant differences between the two groups in BIS index or in plasma concentration of propofol at each predicted concentration. Computer-generated TCI of propofol MCT/LCT during sedation is comparable with that of propofol LCT with respect to pharmacokinetics and pharmacodynamics. The formulation of MCT/LCT has a beneficial effect with respect to less pain on injection.

Intermittent pneumatic foot compression can activate blood fibrinolysis without changes in blood coagulability and platelet activation

BACKGROUND

Intermittent pneumatic foot compression (IPC) is a useful technique for prophylaxis of peri-operative venous thromboembolism. The aim of this study was to determine the effect of IPC on blood coagulation/fibrinolysis and platelet function using a blood viscometer (Sonoclot) and a platelet aggregation monitor (WBA analyzer(TM)), respectively. Using the same blood samples, serum levels of tissue-type plasminogen activator (t-PA), thrombomodulin (TM) and activated protein C (APC) were also measured.

METHODS

The soles and legs of each subject (n = 8) were compressed for 3 s (130 mmHg) at a 0.3-Hz interval using an IPC device. Parameters were measured 2 min before and at the end of 60-min compression.

RESULTS

Parameters of the Sonoclot time-to-peak were shortened and clot retraction rate was increased significantly by IPC, whereas the other parameters did not change. These results indicate that IPC can activate blood fibrinolysis but not coagulability. A parameter of the WBA analyzer PATI (platelet aggregatory threshold index) did not change, indicating that IPC cannot activate platelet function per se. The concentration of t-PA decreased slightly but significantly. A decrease in the concentration of t-PA can lead to activation of fibrinolysis. Other humoral parameters did not change, indicating that IPC has no effect on endothelial function. Although neither blood coagulability nor platelet function were affected by IPC, fibrinolytic activity increased slightly, probably by activation of t-PA function.

CONCLUSION

IPC is useful for prophylaxis for thromboembolism by activation of blood fibrinolysis as well as inhibition of blood stasis.

Reductions in levels of bacterial superantigens/cannabinoids by plasma exchange in a patient with severe toxic shock syndrome

Toxic shock syndrome is a rare but potentially fatal toxin-mediated febrile illness. We report a case of toxic shock syndrome complicated by life-threatening organ dysfunction with high toxin-1 and staphylococcus enterotoxin type A levels that were successfully reduced by early introduction of plasma exchanges. The report shows the time course of the concentrations of anandamide and 2-arachidonyl glyceride and confirms that early introduction of plasma exchange can result in a rapid reduction of circulating toxins and mediators in the treatment of life-threatening multiple organ dysfunction.

Effects of intravenously administered lidocaine on pulmonary vagal afferents and phrenic nerve activity in cats

The ability of lidocaine to suppress activity of single vagal afferent fiber and that of phrenic nerve was studied in 20 cats anesthetized with pentobarbital. Slowly adapting stretch receptors (SAR, n = 16) and rapidly adapting stretch receptors (RAR, n = 7) were identified by their discharge pattern to pulmonary inflation. Intravenous lidocaine (1 mg.kg(-1) or 2 mg.kg(-1)) produced a suppression of SAR activity but not of RAR activity. Suppression of phrenic nerve activity lasted much longer than that of SAR. These findings indicate that iv lidocaine acts more dominantly on CNS than on peripherals. We conclude that iv lidocaine prevents cough and hemodynamic changes caused by airway manipulation mainly through its action on CNS and not on peripherals (peripheral nerves or their receptor).

Wakefulness during the induction with high-dose fentanyl and oxygen anesthesia

The purpose of this study was to investigate the state of wakefulness during the induction of anesthesia with high-dose fentanyl using the isolated forearm technique. Ten patients scheduled for elective cardiovascular surgery were premedicated with morphine (0.15 mg/kg) and scoploamine (0.3-0.4 mg) intramuscularly one hour before induction. The induction of anesthesia was performed by intravenous administration of 100 micro g/kg of fentanyl in 15 min or over. The pneumatic tourniquet applied on the left upper arm was inflated to 220-240 mmHg after 10 micro g/kg of fentanyl was given and then pancuronium was administered. Verbal commands were given to the patient after 25, 50, 75 and 100 micro g/kg of fentanyl was administered. Eight patients out of 10 responded to the verbal commands after administration of 25 micro g/kg of fentanyl. Six patients also responded after administration of 100 micro g/kg of fentanyl and diazepam 5 mg was given to prevent tachycardia and rigidity during endotracheal intubation. Muscle rigidity and tachycardia were noticed in three and four patients respectively. These complications disappeared by diazepam administration. It was noted that wakefulness frequently occurred during the induction by high-dose fentanyl and oxygen anesthesia. To prevent such wakefulness therefore, it is necessary to use anesthetic supplements which do not cause cardiovascular depression.

Coverage dependent desorption dynamics of deuterium on Si(100) surfaces: Interpretation with a diffusion-promoted desorption model

We studied coverage dependence of time-of-flight (TOF) spectra of D2 molecules thermally desorbed from the D/Si(100) surface. The mean translational energies Et of desorbed D2 molecules were found to increase from 0.20+/-0.05 eV to 0.40+/-0.04 eV as the desorption coverage window was decreased from 1.0 ML> or =thetaD> or =0.9 ML to 0.2 ML> or =thetaD> or =0 ML, being consistent with the kinetics switch predicted in the interdimer mechanism. The measured TOF spectra were deconvoluted into 2H, 3H, and 4H components by a curve fitting method along the principle of detailed balance. As a result, it turned out that the desorption kinetics changes from the 4H to the 3H situation at high coverage above thetaD=0.9 ML, while the 2H desorption is dominant for a quite wide coverage region up to thetaD=0.8 ML. A dynamic desorption mechanism by which the desorption is promoted by D-atom diffusion to dangling bonds was proposed.

Left ventricular mechanical performance in elderly patients after induction of anaesthesia. A comparison of inhalational induction with sevoflurane and intravenous induction with fentanyl and propofol

We investigated changes in left ventricular mechanical performance in 40 patients aged > 70 years in whom anaesthesia had been induced with sevoflurane or with fentanyl and propofol. The ratio of ventricular contractility to arterial properties, which reflects left ventricular performance, was estimated from the ratio of ventricular end-systolic elastance to effective arterial elastance. This ratio decreased after induction in both groups, the magnitude of the decrease being significantly greater in the fentanyl/propofol group than in the sevoflurane group. Decreases in mean arterial pressure after induction of anaesthesia in the two groups were similar, whereas the magnitude of the decrease in heart rate in the sevoflurane group was greater than that in the fentanyl/propofol group. Sevoflurane may therefore be preferable to fentanyl and propofol for induction of anaesthesia in elderly patients because of its lesser effect on left ventricular performance.

Modulated hydrogen beam study of adsorption-induced desorption of deuterium from Si(100)-3×1:D surfaces

We have studied the kinetic mechanism of the adsorption-induced-desorption (AID) reaction, H+D/Si(100) --> D2. Using a modulated atomic hydrogen beam, two different types of AID reaction are revealed: one is the fast AID reaction occurring only at the beam on-cycles and the other the slow AID reaction occurring even at the beam off-cycles. Both the fast and slow AID reactions show the different dependence on surface temperature Ts, suggesting that their kinetic mechanisms are different. The fast AID reaction overwhelms the slow one in the desorption yield for 300 K < or = Ts < or = 650 K. It proceeds along a first-order kinetics with respect to the incident H flux. Based on the experimental results, both two AID reactions are suggested to occur only on the 3x1 dihydride phase accumulated during surface exposure to H atoms. Possible mechanisms for the AID reactions are discussed.

The Type of Carbon Dioxide Absorbent has no Relation to the Concentration of Carbon Monoxide in the Breathing Circuit during Low-flow Isoflurane Anaesthesia in Smoking and Non-smoking Subjects

The present study was designed to investigate the concentrations of carbon monoxide (CO) in the anaesthetic circuit and of arterial carboxyhaemoglobin (COHb) during low-flow isoflurane anaesthesia in smoking and non-smoking subjects using three kinds of cardon dioxide (CO2) absorbent. Thirty smoking and 30 non-smoking subjects were selected for this study, and these two groups were each divided into three groups according to the type of CO2absorbent used (Wakolime™A, Drägersorb™Free, and Amsorb™). Anaesthesia was maintained with 1.0% isoflurane and nitrous oxide (1.0l min–1)/oxygen (1.0l min–1). Concentrations of CO in the inspired breathing circuit and concentrations of arterial COHb were measured at 0, 1, 2, 3, and 4 hours after exposure to isoflurane. In the smoking groups there were no significant differences in CO concentrations in the circuit between the groups and the CO concentrations did not change significantly during the study period. There were also no significant differences in the arterial COHb values between the groups and the COHb concentrations remained constant. There was a significant linear correlation between the concentrations of CO and COHb (r=0.86, n=30, P<0.001). In the nonsmoking groups all of the parameters remained constant at low levels that were independent of the type of CO2absorbents tested. The major source for increased intraoperative CO exposure is related to the patient's smoking status, and the type of CO2absorbent used has no relation to an increase in CO concentration in the breathing circuit.

Recovery characteristics and post-operative delirium after long-duration laparoscope-assisted surgery in elderly patients: propofol-based vs. sevoflurane-based anesthesia

BACKGROUND

Post-operative mental dysfunction may be an important problem in elderly patients. This study was designed to compare the effects of propofol and sevoflurane anesthesia on recovery characteristics and the incidence of post-operative delirium (POD) in long-duration laparoscopic surgery for elderly patients.

METHODS

Fifty ASA physical status I-II patients over the age of 65 scheduled for laparoscopic surgery lasting 3 h or more randomly received propofol (group P, n = 25) or sevoflurane (group S, n = 25) for both induction and maintenance of general anesthesia. Both groups were combined with continuous perioperative epidural analgesia. The level of primary anesthetics was adjusted to maintain changes in mean arterial pressure within 20% of the pre-anesthetic values. The emergence times from anesthesia (eye opening, extubation, response to command, and orientation) were recorded, and the occurrence of POD was assessed by the delirium rating scale (DRS) during the first 3 days after surgery. All patients received oxygen and continuous epidural analgesia postoperatively.

RESULTS

Immediate emergence, i.e. eye opening and extubation was significantly faster after sevoflurane (P < 0.05). There was no significant difference between the incidences of POD in the two groups during the first 3 days after surgery. The scores for DRS on day 2 and 3 after surgery, however, were significantly higher in group P than in group S (P < 0.01).

CONCLUSION

Sevoflurane may be preferable to propofol for general anesthesia in combination with epidural analgesia with respect to less effect on mental function during the early postoperative period for long-duration laparoscopic surgery in elderly patients.

Severe paradoxical intracranial embolism and pulmonary emboli during hip hemiarthroplasty

Both paradoxical intracranial embolism, an intracranial arterial embolism caused by venous embolic material that has passed through a right-to-left shunt, and pulmonary arterial embolism are life-threatening complications of joint arthroplasty. We report a case of severe paradoxical intracranial embolism and pulmonary embolism that occurred during hip hemiarthroplasty.

Celite-activated viscometer Sonoclot can measure the suppressive effect of tranexamic acid on hyperfibrinolysis in cardiac surgery

PURPOSE

To investigate the usefulness of the celite-activated viscometer Sonoclot for monitoring fibrinolytic status in cardiac surgery, we demonstrated the effectiveness of high doses of tranexamic acid, an antifibrinolytic agent, in reducing postoperative bleeding.

METHODS

Thirty-two American Society of Anesthesiologists (ASA) physical status III patients who required cardiac surgery with cardiopulmonary bypass (CPB) were studied. Anesthesia was induced by a high dose of fentanyl and midazolam with oxygen and was maintained by the intermittent administration of these agents. Patients were divided into two groups: the control group (n = 15) and patients receiving tranexamic acid (TA; n = 17). The TA group received a high dose (50 mg/kg) of TA twice, once before and once after CPB. The percentage diminishing rate of the Sonoclot tracing 15 min after maximum clot signal (DR(15)) and the amount of postoperative bleeding were measured.

RESULTS

After CPB, DR(15) in the control group (mean 28.3%) increased significantly by 45%, and the DR(15) in the TA group (16.1%) was significantly lower than that in the control group. The amount of postoperative bleeding in the TA group (546 ml) was significantly less, by 34%, than that in the control group (829 ml).

CONCLUSION

Prophylactic administration of high-dose TA in cardiac surgery reduces postoperative bleeding, and this effect is consistent with changes in the diminishing rate using Sonoclot. The celite-activated viscometer Sonoclot is recommended for use in cardiac surgery for rapid assessment of fibrinolytic status.

Cuffed oropharyngeal airway and capnometry: comparison of end-tidal and arterial carbon dioxide pressures

PURPOSE

The aim of this study was to investigate the reliability of end-tidal CO(2) tension (PetCO(2)) as a predictor of PaCO(2) during anesthesia in patients breathing spontaneously via a cuffed oropharyngeal airway (COPA).

METHODS

Twenty adult patients scheduled for minor surgery were included in this study. After propofol injection, an appropriate size of COPA was inserted. Anesthesia was maintained with 60% nitrous oxide in oxygen (total flow rate of 5 l.min(-1)) supplemented with propofol infusion. The patients were allowed to breathe spontaneously throughout the procedure. PaCO(2) and PetCO(2) were simultaneously measured when a steady state of anesthesia was reached.

RESULTS

PaCO(2) (48.8 +/- 5.4 mmHg, range 36.2-58.0 mmHg) was higher than PetCO(2) (43.1 +/- 4.2 mmHg, range 32-51 mmHg) in all patients. The difference between end-tidal and arterial CO(2) tension was 5.7 +/- 3.2 mmHg (range 0.5-13.0 mmHg), and was significantly correlated with PaCO(2) ( P < 0.01).

CONCLUSION

The results of this study suggest that PetCO(2) in anesthetized patients breathing spontaneously through a COPA is sometimes unreliable as an indicator of PaCO(2) level, and there is some possibility of unexpected hypercapnia.

Pneumocephalus following an epidural blood patch

Pneumocephalus is a rare complication of epidural block. We report a case of pneumocephalus complicating an epidural blood patch performed 3 days after unintentional dural puncture. Pneumocephalus may occur during an epidural blood patch procedure, even if the epidural needle tip is within the epidural space.

Effects of volume and concentration of lidocaine on epidural anaesthesia in pregnant females

BACKGROUND AND OBJECTIVE

The effects of altering the concentration of a local anaesthetic on the development of epidural anaesthesia in pregnant females are unclear. We compared the anaesthetic effects of a constant dose of two different concentrations of epidural lidocaine for Caesarean section.

METHODS

After Institutional Review Board approval and informed consent, patients undergoing elective Caesarean section were randomized to receive either lidocaine 1% 30 mL (+epinephrine 5 microg mL(-1)) or lidocaine 2% 15 mL (+epinephrine 5 microg mL(-1)) (n = 20 each) for epidural anaesthesia at the L1-L2 interspace. The spread of the sensory block to pinprick and the degree of motor block (modified Bromage scale) were measured at 5, 10, 15, 20 and 30 min after injection.

RESULTS

No significant differences in the progression of analgesia and motor block were observed at any time between 1 and 2% lidocaine. The maximum cephalad spread was observed 30 min after injection; the median was at T4 (range T3-T5) and at T4 (range T3-T6) for lidocaine 1 and 2%, respectively.

CONCLUSIONS

The same doses but different volumes of lidocaine 1 and 2% produced comparable anaesthetic effects in pregnant females. The effects of epidural anaesthesia depend primarily on the total dose of the local anaesthetic.

Translational heating of D(2) molecules thermally desorbed from Si(100) and Ge(100) surfaces

The translational energies of D(2) molecules thermally desorbed from the Si(100) and Ge(100) surfaces under a heating rate of 6 K/s have been measured. In contrast to the previous laser desorption study, results show a considerable translational heating; the observed translational temperature is about 3 times higher than the desorption temperature for both surfaces. This fact indicates that energy barriers for adsorption are present even in the desorption pathway. Detailed balance is applicable to the adsorption and desorption dynamics of hydrogen on the Si(100) surface.

Rayleigh-Bénard convection with an inclined upper boundary

We report experiments on thermally driven convection of a high-Prandtl-number fluid with an inclined upper boundary. For an inclined angle greater than the critical value, we observed a few new convection patterns, in which laterally migrating convection cells and plumes appear simultaneously and a large-scale flow is induced from the inclined upper boundary. The plumes induced from the inclined upper boundary activate the temperature fluctuations, resulting in the formation of a large-scale horizontal heat transfer with a lateral scale larger than that of each convection cell. The critical angle for the onset of the lateral migration of the cells is determined by comparing the two length scales: the height difference in one convection cell imposed by the inclined upper boundary and the thickness of the viscous boundary layer.

Lightwand intubation is associated with less hemodynamic changes than fibreoptic intubation in normotensive, but not in hypertensive patients over the age of 60

PURPOSE

To compare the effects of the lightwand and fibreoptic techniques for intubation, neither of which require laryngoscopy, on hemodynamic responses associated with tracheal intubation in normotensive and hypertensive elderly patients.

METHODS

Eighty-eight normotensive and hypertensive patients aged more than 60 yr were randomly allocated to either the lightwand (LN and LH group, n=22 in both) or the fibreoptic group (FN and FH group, n=22 in both). All intubations were performed after induction of anesthesia with fentanyl and propofol and muscle relaxation with vecuronium. Systolic and mean arterial pressures (SAP and MAP) and heart rate (HR) were recorded, and rate-pressure product (RPP) and the change from "before intubation" to "immediately after intubation" of each variable (triangle upMAP triangle up,HR and triangle upRPP) were calculated.

RESULTS

In normotensive patients, significantly smaller triangle upMAP, triangle upHR and triangle upRPP were observed in the LN group than in the FN group (P <0.05). In hypertensive patients, no significant differences between the LH group and the FH group were found in triangle upMAP or triangle upHR, while values of mean RPP in both groups were less than 20,000.

CONCLUSION

We conclude that the lightwand technique significantly attenuates hemodynamic changes following intubation in comparison with fibreoptic intubation in normotensive patients over the age of 60. Hemodynamic changes following intubation using the lightwand technique and the fibreoptic technique in hypertensive elderly patients are similar. However, both techniques are useful for intubation in hypertensive elderly patients in terms of RPP.

[Effects of volume and concentration of lidocaine on epidural anesthesia]

We studied 40 patients scheduled for gynecological surgery to evaluate the effects of volume and concentration of lidocaine on epidural anesthesia. We injected lidocaine 300 mg as 1% (30 ml) or 2% (15 ml) through epidural catheter at L 1/2. There was no significant difference in the spread of sensory blockade (cold and pain) and the Bromage scale between the two lidocaine solutions. This result suggests that volume and concentration of lidocaine do not affect the effects of epidural anesthesia.

Involvement of capsaicin-sensitive fibers in spinal NMDA-induced glutamate release

The activation of spinal NMDA receptors can evoke glutamate release through the production of nitric oxide (NO) within the spinal cord, resulting in pain-relating behavior. In this study, we investigated the involvement of capsaicin-sensitive primary afferents in this phenomenon using in vivo intrathecal microdialysis. Intrathecal NMDA perfusion evoked increases in the concentrations of NO metabolises and glutamate and in pain-related behavior in both neonatal capsaicin and vehicle-treated rats. Although the degrees of increase in NO metabolises in capsaicin- and vehicle-treated rats were not significantly different, capsaicin-treated rats showed significantly smaller increases in glutamate concentration and pain-related behavior than did vehicle-treated rats. Our results showed that glutamate release from capsaicin-sensitive primary afferent terminals is involved in spinal NMDA-induced pain.

[The effect of lidocaine on the bispectral index during anesthesia induction with propofol]

We investigated the effect of premixing lidocaine with propofol on a bispectral index (BIS) during propofol infusion. We studied 40 adult patients given mixture of 1% propofol 20 ml with 2 ml of normal saline (control group) or 2% lidocaine (lidocaine group) infused at 2 ml.kg-1.hr-1 for 10 minutes. Heart rate, mean arterial pressure, and BIS were measured every minute. The addition of lidocaine to propofol reduced the incidence of injection pain from 85% to 10% but did not change the induction time. Propofol significantly decreased mean arterial pressure and BIS but there was no difference between the groups. In conclusion, premixing lidocaine with propofol reduces injection pain without affecting the hypnotic effect.

Efficacy of alkalinized lidocaine for reducing pain on intravenous and epidural catheterization

PURPOSE

To investigate whether increasing the pH of lidocaine could reduce the pain caused by its skin infiltration as well as that caused by intravenous and epidural needle insertion.

METHODS

A randomized, double-blind trial was undertaken in patients who were allocated to receive topical anesthesia with either plain (plain group; n = 25) or alkalinized lidocaine (alkalinized group; n = 25). An alkalinized lidocaine solution was prepared by adding 8.4% sodium bicarbonate to a plain 1% lidocaine solution at a ratio of 1 : 10. Pain was assessed using the verbal analog scale (VAS).

RESULTS

In the alkalinized group, the VAS scores on skin infiltration in the hand (2.5 +/- 1.4) and the back (2.7 +/- 1.4) were significantly lower than the respective scores in the plain group (3.5 +/- 1.4, and 4.9 +/- 1.9). Although the VAS score on intravenous needle insertion did not differ between the two groups, the VAS score on epidural needle insertion was significantly lower in the alkalinized group (1.3 +/- 1.0) than in the plain group (3.6 +/- 1.3).

CONCLUSIONS

Alkalinization of lidocaine was effective in attenuating pain on skin infiltration and on epidural needle insertion.

Mechanisms of direct inhibitory action of propofol on uterine smooth muscle contraction in pregnant rats

BACKGROUND

Although propofol directly inhibits uterine smooth muscle contraction, the mechanisms of this effect are still unknown. The current study aimed to clarify the mechanisms of the inhibitory effect of propofol on oxytocin-induced uterine smooth muscle contraction by measuring (1) the concentration of intracellular free Ca(2+) ([Ca(2+)](i)) simultaneously with muscle tension, (2) the amount of intracellular inositol 1,4,5-triphosphate ([IP(3)](i)), and (3) voltage-dependent Ca(2+) channel (VDCC) activity.

METHODS

Uterine smooth muscle tissues were obtained from pregnant rats (in late gestation). [Ca(2+)](i) with isometric tension was monitored by the 500-nm light emission ratio of preloaded Ca(2+) indicator fura-2. [IP(3)](i) and VDCC activity were measured by radioimmunoassay and patch clamp techniques, respectively. The uterine smooth muscle was stimulated by 20 nm oxytocin and exposed to propofol (10(-7) approximately 10(-4) m).

RESULTS

Propofol had significant inhibitory effects on oxytocin-induced uterine smooth muscle contraction and increased [Ca(2+)](i) in pregnant rats in a dose-dependent manner, without affecting the agonist-receptor binding affinity. Propofol inhibited the increase in [IP(3)](i) induced by oxytocin. Propofol also inhibited VDCC activity in both activated and inactivated states. The solvent Intralipid had no effects on these parameters.

CONCLUSIONS

Propofol inhibits oxytocin-induced uterine smooth muscle contraction, at least in part, by decreasing [Ca(2+)](i) without affecting agonist-receptor binding; the inhibitory effect of propofol on [Ca(2+)](i) might be mediated both by a decrease in [IP(3)](i) and by inhibition of VDCC activity.

[Swelling of the tongue after intraoperative monitoring by transesophageal echocardiography]

Tongue swelling after surgery is a rare but potentially lethal postoperative complication. This is a case report of a 62-yr-old patient who developed tongue swelling after intraoperative monitoring by transesophageal echocardiography. The patient underwent replacement of the descending aorta with an interposition graft under cardiopulmonary bypass. A transesophageal echocardiography (TEE) probe was inserted after the induction of general anesthesia. Surgery and anesthesia were uneventful. After the surgical procedure, the TEE probe was removed. At that time, marked swelling of the tongue was noted. However, there was no diffuse edema in the neck, face, supraglottic structures or the larynx. The tongue swelling was thought to have been caused by local mechanical compression of the tongue with the TEE probe. The tongue returned to normal size the next day. Care should be taken to prevent the occurrence of this complication during and after TEE examination under general anesthesia.