The Effects of Desflurane on Ca2+ Release from the Myocardial Sarcoplasmic Reticulum in Vitro

Background: The purpose of this study is to examine the effect of Desflurane on myocardial contractility and cellular electrophysiologic behabior in isolated guinea pig and rat right ventricular papillary muscle. Methods: The isometric force of a guinea pig ventricular papillary muscle was studied in normal and 26 mM Tyrode's solution at various stimulation rates. Experiments using rat papillary muscles under normal Tyrode's solution at resting-state (RS) and using guinea pig papillary muscles under low Na Tyrode's solution (25 mM) were performed to evaluate the effect on Ca2+ release from the sarcoplasmic reticulum (SR). Normal and slow action potentials (APs) were evaluated by using a conventional microelectrode technique. Effects of desflurane on SR function in situ were examined by its effect on rapid colling contractures (RCCs). 1 MAC (end-tidal concentration: 6%) and 2 MAC desflurane were applied. Results: Desflurane equivalent to 6% and 12% depressed guinea pig myocardial contractions in the control to -70% and -40% from RS to 3 Hz stimulation rates. Contractile force after rest in rat and guinea pig myocardium under low Na+ Tyrode's solution showed modest depression. In the partially depolarized, β-adrenergically stimulated myocardium, 6% and 12% desflurane caused marked depression of late force (6%: -60%, 12%: -80%) with moderate changes of early peak force (6%: -20%, 12%: -40%). RCCs were abolished at 6% concentration. Conclusions: The direct myocardial depressant effects of desflurane is slightly greater to those seen with isoflurane. The rapid initial release of Ca2+ from the SR by depolarization seems to be modestly depressed, although certain release pathways induced by rapid colling appear to be markedly depressed.ope

Pain Dynamics-Cortical Observation with f-MRI

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Partial Obstruction of an Armored Endotracheal Tube during a Carotid Endarterectomy due to Tracheal Deviation in a Pnemonectomized Patient

Endotracheal tube obstruction during anesthesia can have many causes. Hyperinflation of the remaining lung after a pneumonectomy can severely displace the trachea, and attachment of an endotracheal tube tip to the wall of a deviated trachea may also cause severe airway obstruction. The right lung of the patient was removed 3 years ago due to lung cancer. Compensatory hyperinflation of the left lung and severe right-sided tracheal deviation was seen on a chest X-ray. An armored endotracheal tube without Murphy's eye was used. Two hours after beginning the operation, peak airway pressure and PETCO2 began to increase gradually. A wheezing-like sound was heard. Bronchospasm was suspected, but signs of a spasm were not relieved by medications. The signs completely disappeared after pulling the tube 2 cm proximal. The position of the tube should be confirmed by fiberoptic bronchoscopy or chest X-ray after intubation when the trachea is deviated.ope

Cortical Observation by fMRI

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Spatiotemporal changes of optical signals in the somatosensory cortex of neuropathic rats after electroacupuncture stimulation

BACKGROUND: Peripheral nerve injury causes physiological changes in primary afferent neurons. Neuropathic pain associated with peripheral nerve injuries may reflect changes in the excitability of the nervous system, including the spinothalamic tract. Current alternative medical research indicates that acupuncture stimulation has analgesic effects in various pain symptoms. However, activation changes in the somatosensory cortex of the brain by acupuncture stimulation remain poorly understood. The present study was conducted to monitor the changes in cortical excitability, using optical imaging with voltage-sensitive dye (VSD) in neuropathic rats after electroacupuncture (EA) stimulation. METHODS: Male Sprague-Dawley rats were divided into three groups: control (intact), sham injury, and neuropathic pain rats. Under pentobarbital anesthesia, rats were subjected to nerve injury with tight ligation and incision of the tibial and sural nerves in the left hind paw. For optical imaging, the rats were re-anesthetized with urethane, and followed by craniotomy. The exposed primary somatosensory cortex (S1) was stained with VSD for one hour. Optical signals were recorded from the S1 cortex, before and after EA stimulation on Zusanli (ST36) and Yinlingquan (SP9). RESULTS: After peripheral stimulation, control and sham injury rats did not show significant signal changes in the S1 cortex. However, inflamed and amplified neural activities were observed in the S1 cortex of nerve-injured rats. Furthermore, the optical signals and region of activation in the S1 cortex were reduced substantially after EA stimulation, and recovered in a time-dependent manner. The peak fluorescence intensity was significantly reduced until 90 min after EA stimulation (Pre-EA: 0.25 ± 0.04 and Post-EA 0 min: 0.01 ± 0.01), and maximum activated area was also significantly attenuated until 60 min after EA stimulation (Pre-EA: 37.2 ± 1.79 and Post-EA 0 min: 0.01 ± 0.10). CONCLUSION: Our results indicate that EA stimulation has inhibitory effects on excitatory neuronal signaling in the S1 cortex, caused by noxious stimulation in neuropathic pain. These findings suggest that EA stimulation warrants further study as a potential adjuvant modulation of neuropathic pain.ope

Motor Weakness on Lower Extremities after the Combined Spinal-epidural Anesthesia and Analgesia

The spinal-epidural nerve block is widely used for anesthesia or postoperative pain control. The incidence of neurological complications after spinal and epidural anesthesia is increased although it is usually transient. Such complications may be caused by various mechanical, chemical, and ischemic factors. We experienced a case of motor weakness following combined spinal-epidural anesthesia and analgesia. The motor weakness and hypoesthesia were reversible on right leg, but persistent on left leg.ope

Functional Mapping of Nervous System Using Optical Imaging Techniques

Functional mapping techniques including functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and magnetoencephalography (MEG) can be used to study the function of the nervous system. Optical imaging is an emerging technique for functional imaging of the nervous tissue. Functional optical imaging can be classified into two major streams; intrinsic signal optical imaging (ISO) and voltage-sensitive dye optical imaging (VDO). ISO is related to hemodynamic changes such as hemoglobin concentration and oxygenation changes, cytochrome oxidation change, and light scattering. On the contrary, VOD measures changes in membrane potentials of neural cells. Therefore, ISO reflects metabolic activity of neurons, while VOD directly reflects neural activity. Recent advances in optical imaging opened the possibility of its application to clinical situations as well as basic researches. Further, development of optical imaging may greatly contribute to the understanding of the function of the nervous system.ope

Risk factors and safety measures in the operation room

Hospital personnel are subject to various occupational hazards. Along with the development of modern medicine, novel and diverse medical appliances have been introduced to enhance the safety of the hospital environment. But paradoxically, some advancement of the appliances have led to exposure to greater risk for the personnel in the operation room. In the past, the greatest risk factor in the operation room was outbreak of fire and explosion, but the risk of explosion has vanished by the development of nonexplosive anesthetics. However, newly introduced electrical appliances and unknown infectious diseases appear to be new risk factors affecting health workers in the operation room. The goal of this review is to investigate the current risk factors and thereby prepare suitable preventive methods. We have reviewed the main occupational hazards affecting health workers in the operation room: accidents such as fires, explosions, electrical accidents; exposure to residual anesthetic gas; radiation; various infections; drug dependencies.ope

Effects of Acupuncture Stimulation at Different Acupoints on Formalin-Induced Pain in Rats

Acupuncture is the process of stimulating skin regions called meridians or acupoints and has been used to treat pain-related symptoms. However, the pain-relieving effects of acupuncture may be different depending on acupoints. In the present study, the effects of acupuncture on behavioral responses and c-Fos expression were evaluated using a formalin test in male Sprague-Dawley rats in order to clarify the analgesic effects of three different acupoints. Each rat received manual acupuncture at the ST36 (Zusanli), SP9 (Yinlingquan) or BL60 (Kunlun) acupoint before formalin injection. Flinching and licking behaviors were counted by two blinded investigators. Fos-like immunoreactivity was examined by immunohistochemistry in the rat spinal cord. Manual acupuncture treatment at BL60 acupoint showed significant inhibition in flinching behavior but not in licking. Manual acupuncture at ST36 or SP9 tended to inhibit flinching and licking behaviors but the effects were not statistically significant. The acupuncture at ST36, SP9, or BL60 reduced c-Fos expression as compared with the control group. These results suggest that acupuncture especially at the BL60 acupoint is more effective in relieving inflammatory pain than other acupoints.ope

New Trend of Pain Study by Brain Imaging Devices

The study of pain has recently received much attention, especially in understanding its neurophysiology by using new brain imaging techniques, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), both of which allow us to visualize brain function in vivo. Also the new brain imaging devices allow us to evaluate the patients pain status and plan to treat patients objectively. Functional activation of brain regions are thought to be reflected by increases in the regional cerebral blood flow in the brain imaging studies. Regional cerebral blood flow increases to noxious stimuli are observed in second somatic (SII) and insular regions and in the anterior cingulate cortex and with slightly less consistency in the first somatic area (S1), motor area, supplementary motor area, prefrontal area, amygdala and contralateral thalamus. These data suggest that pain has multidimensions such as sensory-discrimitive, motivational-affective and cognitive-evaluativeope