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Tetsuo Satoh - One of the best experts on this subject based on the ideXlab platform.
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The interaction between propofol and clonidine for Loss of Consciousness.
Anesthesia and analgesia, 2002Co-Authors: Hideyuki Higuchi, Yushi U. Adachi, Albert Dahan, Erik Olofsen, Shinya Arimura, Tomohisa Mori, Tetsuo SatohAbstract:UNLABELLED Clonidine premedication reduces the intraoperative requirement for opioids and volatile anesthetics. Clonidine also reduces the induction dose of IV anesthetics. There is no information, however, regarding the effect of oral clonidine premedication on the propofol blood concentrations required for Loss of Consciousness, and the interaction between propofol and clonidine. We randomly administered target effect-site concentrations of propofol ranging from 0.5 to 5. 0 microg/mL by using computer-assisted target-controlled infusion to 3 groups of healthy male patients: Control (n = 35), 2.5 microg/kg Clonidine (n = 36), and 5.0 microg/kg Clonidine (n = 36) groups. Nothing was administered to the Control group. Clonidine (2.5 or 5.0 microg/kg) was administered orally 90 min before the induction of anesthesia in the Clonidine groups. After equilibration between the blood and effect-site for 15 min, a verbal command to open their eyes was given two times to the patients. Arterial blood samples for analysis of the serum propofol and clonidine concentrations were taken immediately before verbal commands were given. Measured serum propofol concentrations in equilibrium with the effect-site at which 50% of the patients did not respond to verbal commands (EC50 for Loss of Consciousness) were determined by logistic regression. The EC50 +/- SE values in the Control, 2.5 microg/kg Clonidine, and 5.0 microg/kg Clonidine groups were 2.67 +/- 0.18, 1.31 +/- 0.12, and 0.91 +/- 0.13 microg/mL, respectively. The EC50 in the 2.5 and 5.0 microg/kg clonidine groups was significantly smaller than that in the Control group (P < 0.001). The use of a response surface modeling analysis indicated that there was an additive interaction between measured arterial propofol and clonidine concentrations in relation to Loss of Consciousness. These results indicate that propofol and clonidine act additively for Loss of Consciousness. IMPLICATIONS Oral clonidine 2.5 and 5.0 microg/kg premedication decreases the propofol concentration required for Loss of Consciousness.
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Early pregnancy does not reduce the C50 of propofol for Loss of Consciousness
Anesthesia and analgesia, 2001Co-Authors: Hideyuki Higuchi, Yushi U. Adachi, Shinya Arimura, Masuyuki Kanno, Tetsuo SatohAbstract:UNLABELLED Requirements for inhaled anesthetics decrease during pregnancy. There are no published data, however, regarding propofol requirements in these patients. Because propofol is often used for induction of general anesthesia when surgery is necessary in early pregnancy, we investigated whether early pregnancy reduces the requirement of propofol for Loss of Consciousness using a computer-assisted target-controlled infusion (TCI). Propofol was administered using TCI to provide stable concentrations and to allow equilibration between blood and effect-site (central compartment) concentrations. Randomly selected target concentrations of propofol (1.5-4.5 microg/mL) were administered to both pregnant women (n = 36) who were scheduled for pregnancy termination and nonpregnant women (n = 36) who were scheduled for elective orthopedic or otorhinolaryngologic surgery. The median gestation of the pregnant women was 8 wk (range, 6-12 wk). Venous blood samples for analysis of the serum propofol concentration were taken at 3 min and 8 min after equilibration of the propofol concentration. After a 10-min equilibration period of the predetermined propofol blood concentration, a verbal command to open their eyes was given to the patients twice, accompanied by rubbing of their shoulders. Serum propofol concentrations at which 50% of the patients did not respond to verbal commands (C(50) for Loss of Consciousness) were determined by logistic regression. There was no significant difference in C(50) +/- SE of propofol for Loss of Consciousness between the Nonpregnant (2.1 +/- 0.2 microg/mL) and Pregnant (2.0 +/- 0.2 microg/mL) groups. These results indicate that early pregnancy does not decrease the concentration of propofol required for Loss of Consciousness. IMPLICATIONS The C(50) of propofol for Loss of Consciousness in early pregnancy did not differ from that in nonpregnant women, indicating that there is no need to decrease the propofol concentration for Loss of Consciousness when inducing general anesthesia for termination of pregnancy.
Peter O’callaghan - One of the best experts on this subject based on the ideXlab platform.
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Transient Loss of Consciousness
Medicine, 2012Co-Authors: Peter O’callaghanAbstract:Transient Loss of Consciousness (T-LOC) is usually caused by cardiovascular (syncope), neurological (seizure) and psychological (non-epileptic attack disorder) conditions. Suspected cardiovascular causes should be further defined as reflex/blood pressure regulatory or cardiac/heart rhythm disorders. Identifying select individuals at high risk of sudden death from a large cohort of patients with more benign causes of T-LOC is a major challenge. The key to assessing a patient with T-LOC lies in a detailed history. Risk stratification into patients at high and low risk of future cardiac arrest should be an integral part of the initial assessment of every T-LOC patient. Risk stratification is easily performed by considering the presence or absence of structural heart disease and family history of sudden unexplained death below 40 years of age, and by systematic analysis of a 12-lead electrocardiograph. Patients with high-risk features whose T-LOC is thought to be cardiovascular in origin should be referred to a heart rhythm specialist for urgent assessment. In these cases, T-LOC is an opportunity to intervene with highly effective therapies before a cardiac arrest occurs.
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Transient Loss of Consciousness (‘blackouts’) in adults and young people (NICE)
Practical neurology, 2011Co-Authors: Philip E. M. Smith, Peter O’callaghanAbstract:The appealing title of this weighty guideline from the UK's National Institute of Health and Clinical Excellence (NICE) on the ‘Management of transient Loss of Consciousness (blackouts) in adults and young people’1 carries the burden of great expectation. Every physician recognises transient Loss of Consciousness as common yet frequently misdiagnosed. For example, in neurological practice, many people labelled and treated as having epilepsy turn out to have something else. More importantly, many unrecognised cardiac causes of blackouts are mislabelled and then mistreated as epilepsy. We clearly do need guidance to focus investigations and management in a coordinated and efficient way. For neurologists, however, this document will be a disappointment—few will get through the 429 pages plus appendices with its strong cardiological emphasis, its bare mention of epilepsy and its almost complete omission of psychogenic non-epileptic attacks. The indications for brain imaging and EEG in patients with transient Loss of Consciousness are not discussed. Cardiologists, by contrast, will find a document written with them in mind, heavily focused on recognising underlying cardiac disease following blackouts, promising much additional service work in specialist ECG interpretation and rapid access referral. Transient Loss of Consciousness is of course very common (perhaps 30% of the population is affected at some point …
Rose Anne Kenny - One of the best experts on this subject based on the ideXlab platform.
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amnesia for Loss of Consciousness is common in vasovagal syncope
Europace, 2011Co-Authors: Clodagh Odwyer, Kathleen Bennett, Yvonne Langan, Chie Wei Fan, Rose Anne KennyAbstract:Aims The aim of this study was to determine the prevalence of amnesia for Loss of Consciousness (A-LOC) in those who have a history suggestive of vasovagal syncope (VVS) and who develop syncope on head-up tilt (HUT) table testing. Furthermore, we wished to determine if A-LOC is an age-dependent phenomenon in VVS and whether haemodynamic parameters on tilting can predict for A-LOC. Methods and results Patients were recruited in a dedicated syncope unit and underwent neurocardiovascular evaluation as indicated under European Society of Cardiology guidelines to illicit a diagnosis of VVS. A set protocol of questioning occurred following induced syncope to determine the presence of A-LOC. The prevalence of A-LOC following syncope on tilting was 28% (44/159). Forty-two per cent of those ≥ 60 years of age vs. 20% <60 years of age experienced amnesia post-induced syncope ( P = 0.003). However, regression analysis did not show age to be an independent predictor for A-LOC. Blood pressure change between those without amnesia and those with amnesia showed no significant difference ( P = 0.687). There was a significant difference in heart rate response; those experiencing amnesia had reduced bradycardic response on HUT compared with those without amnesia ( P = 0.001). Conclusion Amnesia for Loss of Consciousness is common in VVS. Although more prevalent, it is not unique to older age-groups. Absence of syncope associated bradycardia during HUT testing predicts for A-LOC.
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amnesia for Loss of Consciousness in carotid sinus syndrome implications for presentation with falls
Journal of the American College of Cardiology, 2005Co-Authors: Steve W Parry, Nick I Steen, Mary Baptist, Rose Anne KennyAbstract:OBJECTIVES The goal of this study was to compare the clinical characteristics of patients with carotid sinus syndrome who presented with falls with those who presented with syncope. BACKGROUND Carotid sinus syndrome presents with both falls and syncope. The reasons for this differential presentation are unknown, but amnesia for Loss of Consciousness may be the underlying cause. METHODS Two groups of 34 consecutive patients with carotid sinus syndrome as the sole cause of falls and syncope were recruited. Cognitive function and clinical characteristics were compared between the two groups. RESULTS Syncopal subjects with carotid sinus syndrome were more likely to be older males (18 [53%] vs. 7 [21%] years; p = 0.006) with a longer duration of symptoms (27.9 vs. 13.3 months; p = 0.009) and more soft tissue injuries (19 [56%] vs. 9 [26%]; p = 0.03). Duration of asystole during carotid sinus massage was similar in both groups (5.1 vs. 5.4 s; p = 0.42), but witnessed amnesia for Loss of Consciousness was more frequent in fallers than those with syncope (21 [95%] vs. 4 [12%]; p < 0.001). Clinical characteristics and cognitive function were otherwise similar in both groups. CONCLUSIONS Patients with carotid sinus syndrome have similar rates of witnessed Loss of Consciousness during laboratory testing regardless of symptoms. However, those presenting with falls are far less likely to perceive any disturbance of Consciousness than those with syncope, showing for the first time the manner in which such patients manifest symptoms. Cognitive impairment does not explain the amnesia for Loss of Consciousness seen in fallers with carotid sinus syndrome.
Hideyuki Higuchi - One of the best experts on this subject based on the ideXlab platform.
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The interaction between propofol and clonidine for Loss of Consciousness.
Anesthesia and analgesia, 2002Co-Authors: Hideyuki Higuchi, Yushi U. Adachi, Albert Dahan, Erik Olofsen, Shinya Arimura, Tomohisa Mori, Tetsuo SatohAbstract:UNLABELLED Clonidine premedication reduces the intraoperative requirement for opioids and volatile anesthetics. Clonidine also reduces the induction dose of IV anesthetics. There is no information, however, regarding the effect of oral clonidine premedication on the propofol blood concentrations required for Loss of Consciousness, and the interaction between propofol and clonidine. We randomly administered target effect-site concentrations of propofol ranging from 0.5 to 5. 0 microg/mL by using computer-assisted target-controlled infusion to 3 groups of healthy male patients: Control (n = 35), 2.5 microg/kg Clonidine (n = 36), and 5.0 microg/kg Clonidine (n = 36) groups. Nothing was administered to the Control group. Clonidine (2.5 or 5.0 microg/kg) was administered orally 90 min before the induction of anesthesia in the Clonidine groups. After equilibration between the blood and effect-site for 15 min, a verbal command to open their eyes was given two times to the patients. Arterial blood samples for analysis of the serum propofol and clonidine concentrations were taken immediately before verbal commands were given. Measured serum propofol concentrations in equilibrium with the effect-site at which 50% of the patients did not respond to verbal commands (EC50 for Loss of Consciousness) were determined by logistic regression. The EC50 +/- SE values in the Control, 2.5 microg/kg Clonidine, and 5.0 microg/kg Clonidine groups were 2.67 +/- 0.18, 1.31 +/- 0.12, and 0.91 +/- 0.13 microg/mL, respectively. The EC50 in the 2.5 and 5.0 microg/kg clonidine groups was significantly smaller than that in the Control group (P < 0.001). The use of a response surface modeling analysis indicated that there was an additive interaction between measured arterial propofol and clonidine concentrations in relation to Loss of Consciousness. These results indicate that propofol and clonidine act additively for Loss of Consciousness. IMPLICATIONS Oral clonidine 2.5 and 5.0 microg/kg premedication decreases the propofol concentration required for Loss of Consciousness.
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Early pregnancy does not reduce the C50 of propofol for Loss of Consciousness
Anesthesia and analgesia, 2001Co-Authors: Hideyuki Higuchi, Yushi U. Adachi, Shinya Arimura, Masuyuki Kanno, Tetsuo SatohAbstract:UNLABELLED Requirements for inhaled anesthetics decrease during pregnancy. There are no published data, however, regarding propofol requirements in these patients. Because propofol is often used for induction of general anesthesia when surgery is necessary in early pregnancy, we investigated whether early pregnancy reduces the requirement of propofol for Loss of Consciousness using a computer-assisted target-controlled infusion (TCI). Propofol was administered using TCI to provide stable concentrations and to allow equilibration between blood and effect-site (central compartment) concentrations. Randomly selected target concentrations of propofol (1.5-4.5 microg/mL) were administered to both pregnant women (n = 36) who were scheduled for pregnancy termination and nonpregnant women (n = 36) who were scheduled for elective orthopedic or otorhinolaryngologic surgery. The median gestation of the pregnant women was 8 wk (range, 6-12 wk). Venous blood samples for analysis of the serum propofol concentration were taken at 3 min and 8 min after equilibration of the propofol concentration. After a 10-min equilibration period of the predetermined propofol blood concentration, a verbal command to open their eyes was given to the patients twice, accompanied by rubbing of their shoulders. Serum propofol concentrations at which 50% of the patients did not respond to verbal commands (C(50) for Loss of Consciousness) were determined by logistic regression. There was no significant difference in C(50) +/- SE of propofol for Loss of Consciousness between the Nonpregnant (2.1 +/- 0.2 microg/mL) and Pregnant (2.0 +/- 0.2 microg/mL) groups. These results indicate that early pregnancy does not decrease the concentration of propofol required for Loss of Consciousness. IMPLICATIONS The C(50) of propofol for Loss of Consciousness in early pregnancy did not differ from that in nonpregnant women, indicating that there is no need to decrease the propofol concentration for Loss of Consciousness when inducing general anesthesia for termination of pregnancy.
Stephan A. Mayer - One of the best experts on this subject based on the ideXlab platform.
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Loss of Consciousness at Onset of Subarachnoid Hemorrhage as an Important Marker of Early Brain Injury.
JAMA neurology, 2016Co-Authors: Sureerat Suwatcharangkoon, Emma Meyers, Cristina Falo, J. Michael Schmidt, Sachin Agarwal, Jan Claassen, Stephan A. MayerAbstract:Importance Loss of Consciousness (LOC) is a common presenting symptom of subarachnoid hemorrhage (SAH) that is presumed to result from transient intracranial circulatory arrest. Objective To clarify the association between LOC at onset of SAH, complications while in the hospital, and long-term outcome after SAH. Design, Setting, and Participants A retrospective analysis was conducted of 1460 consecutively treated patients with spontaneous SAH who were part of a prospective observational cohort study at a large urban academic medical center (the Columbia University SAH Outcomes Project or SHOP). Patients were enrolled between August 6, 1996, and July 23, 2012. Analysis was conducted from December 1, 2013, to February 28, 2015. Exposures Loss of Consciousness at onset was identified by structured interview of the patient and first responders. Patients (80.5%) were observed for up to 1 year to assess functional recovery. Main Outcomes and Measures Modified Rankin scale scores were assigned based on telephone or in-person interviews of the patient, family members, or caregivers. Complications while in the hospital were predefined and adjudicated by the study team. Results Five hundred ninety patients (40.4%) reported LOC at onset of SAH. Loss of Consciousness was associated with poor clinical grade, more subarachnoid and intraventricular blood seen on admission computed tomographic scan, and a higher frequency of global cerebral edema ( P P P P Conclusions and Relevance Loss of Consciousness at symptom onset is an important manifestation of early brain injury after SAH and a predictor of death or poor functional outcome at 12 months.
