Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CONSCIOUSNESS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,297 records · Page 72Linked to original sources
PubMed1999

The cerebellum plays a role in conscious episodic memory retrieval.

The cerebellum has traditionally been considered to be primarily dedicated to motor functions. Its phylogenetic development and connectivity suggest, however, that it also may play a role in cognitive processes in the human brain. In order to examine a potential cognitive role for the cerebellum in human beings, a positron emission tomography (PET) study was conducted during a "pure thought experiment": subjects intentionally recalled a specific past personal experience (consciously retrieved episodic memory). Since there was no motor or sensory input or output, the design eliminated the possibility that cerebellar changes in blood flow were due to motor activity. During silent recall of a consciously retrieved episodic memory, activations were observed in the right lateral cerebellum, left medial dorsal thalamus, medial and left orbital frontal cortex, anterior cingulate, and a left parietal region. These activations confirm a cognitive role for the cerebellum, which may participate in an interactive cortical-cerebellar network that initiates and monitors the conscious retrieval of episodic memory.

Adult↗
PubMed2000

Minilaparoscopic ovarian biopsy performed under conscious sedation in women with premature ovarian failure.

OBJECTIVE: To evaluate the feasibility of a bilateral multiple ovarian biopsy through minilaparoscopy under local anesthesia and conscious sedation and to assess the efficacy of this technique as compared to the traditional laparoscopic approach. STUDY DESIGN: Twenty-five infertile women with premature ovarian failure underwent bilateral ovarian biopsy plus chromoperturbation. Twelve patients were treated with minilaparoscopy (minilap group) and preoperatively received mepivacaine for subcutaneous local anesthesia and midazolam plus fentanyl for conscious sedation. Following minilaparoscopy, 40 mL of 0.5% intraperitoneal subdiaphragmatic lidocaine and 5 mL of ropivacaine, 7.5 mg/mL, for infiltration of the trocar insertion sites were administered. Thirteen women (control group) were treated with the traditional laparoscopic approach under general anesthesia. If necessary, ketoprofene or intramuscular ketorolac was administered following surgery. Postoperative pain score was evaluated by a 1-10 visual analogic scale immediately after surgery and in the following 24 hours; in addition, the quantity of ovarian biopsy material for the pathologist and the discharge and operative times were evaluated. RESULTS: The minilap group had lower postoperative pain scores postoperatively. Operative time was similar in both groups. The rate of discharge two hours after surgery was significantly higher in the minilap group. In all cases the amount of ovarian tissue was sufficient for diagnosis. Twenty-one patients were affected by premature menopause and four by resistant ovary syndrome. The need for postoperative analgesics was significantly higher in the control group. CONCLUSION: Minilap allows the performance of bilateral, multiple ovarian biopsy under local anesthesia and conscious sedation in association with chromoperturbation and the obtaining a sufficient amount of ovarian tissue for histopathologic diagnosis. Intraperitoneal lidocaine administration and ropivacaine infiltration of the trocar sites were beneficial for patients undergoing operative minilap in a day-surgery setting. The effect of these drugs was obviously temporary; however, low postoperative pain scores and low additional analgesic requirement permitted early discharge, within two hours after surgery.

Adult↗
PubMed1998

Minipig model for the study of voiding parameters in the conscious state and natural posture: normal urodynamic profiles.

OBJECTIVE: To provide baseline data on an animal model in which collecting and voiding can be accurately characterized urodynamically in the conscious state and natural posture. METHODS: Thirty-one female Yucatan microswines (age 4-8 months, weight 11-43 kg) were used. Portcatheters were placed in the bladder and peritoneal cavity, and reservoirs were implanted under the back skin for easy access. For urodynamic study, conscious pigs were restrained in specially designed adjustable cages. The portcatheter reservoirs were connected by 20-gauge needles and tubings to a UDS-120 digital computer polygraph to measure the total bladder pressure (pves) and abdominal pressure (pabd). A flow meter was placed behind and underneath the animal to measure the uroflow. Diuresis was induced with furosemide, and 2-4 voiding cycles were monitored. Isovolumetric detrusor pressure (pdet, isv) was obtained in the last cycle by manual interruption of flow per vagina. Urodynamic investigations were performed satisfactorily in all animals. RESULTS: The voided volume was 102-340 ml (mean 181.7 +/- 11.9 ml). Seven pigs had residual urine (4-39 ml, mean 14.3 +/- 4.7 ml). The initial opening pressure at the start of voiding was 19.9 +/- 1.5 cmH2O; detrusor pressure at maximum flow rate was 15.7 +/- 1.3 cmH2O; average flow was 12.6 +/- 0.7 ml/s; maximum flow rate was 20.7 +/- 1.1 ml/s; pdet, isv was 51.6 +/- 2.4 cmH2O; flow time was 15.9 +/- 1.2 seconds; mean resistance factor (R) was 0.06 +/- 0.01 cmH2O ml-2s2; mean urethral resistance factor (URA) was 7.10 +/- 0.51 cmH2O; and mean strength of voiding detrusor contraction was 3.91 +/- 0.20 W/m2. CONCLUSION: The above model allows reliable measurement of pressure-flow parameters in the conscious state and natural posture, permitting in-vivo urodynamic characterization of obstructive voiding dysfunction and correlation with detrusor structure.

Animals↗
PubMed2001

Central bromocriptine-induced tachycardia is reversed to bradycardia in conscious, deoxycorticosterone acetate-salt hypertensive rats.

A central dopaminergic origin has been demonstrated for the bromocriptine-induced tachycardia in conscious, normotensive rats. The present study investigated the effect of bromocriptine on heart rate and the principal site of action of this agonist in conscious, deoxycorticosterone acetate-salt hypertensive rats, in which altered central dopaminergic activity has been previously reported. Intravenous administration of bromocriptine (150 microg/kg) increased heart rate (49+/-5 beats/min.) in uninephrectomized control rats, while it induced a significant bradycardia (50+/-6 beats/min.) in deoxycorticosterone acetate-salt hypertensive rats. In the latter animals, intravenous (500 microg/kg) or intrathecal (40 microg/rat at T9-T10) pretreatment with domperidone, a selective dopamine D2 receptor antagonist that does not cross the blood-brain barrier, reduced partially, but significantly, the bradycardiac responses to bromocriptine (reduction of about 44% and 48% of the maximal effect, respectively). In contrast, the bromocriptine-induced bradycardia was fully abolished by intravenous pretreatment with metoclopramide (300 microg/kg), a dopamine D2 receptor antagonist that crosses the blood-brain barrier, or by combined pretreatment with intravenous and intrathecal domperidone. These results indicate that, in deoxycorticosterone acetate-salt hypertensive rats, bromocriptine decreases rather than increases heart rate, an effect that is mediated partly through a peripheral D2 dopaminergic mechanism and partly through stimulation of spinal dopamine D2 receptors. They further support the concept that, in normotensive, conscious rats, the central tachycardia of bromocriptine appears to predominate and to mask the bradycardia of this agonist at both peripheral and spinal dopamine D2 receptors.

Animals↗
PubMed1997

[Effect of loss of consciousness induced by repeated lower body negative pressure on blood-brain barrier permeability in rats].

To investigate the effect of loss of consciousness induced by repeated +Gz on the brain and its mechanism, changes of blood-brain barrier (BBB) permeability and brain water content after repeated lower body negative pressure (LBNP) induced loss of consciousness were observed in 30 rats. Rats were anesthetized and exposed to LBNP (-4.0 kPa). The pressure rapidly returned to control level 2 min after EEG became isoelectric. The BBB permeability was measured using lanthanum trace labeling with electron microscopy and brain water content was determined after one or three LBNP exposures. Most tight junctions among endothelial cells opened through which the lanthanum entered into the neurons and extra cellular space and water content in brain tissues increased significantly (P < 0.05) 1 h after 3 LBNP exposures. It demonstrated that 3 exposures to LBNP induced loss of consciousness can result in an increase of BBB permeability in rats, which may play an important role in the development of G-induced brain edema.

Aerospace Medicine↗
PubMedDate not supplied

Factors associated with administration route when using midazolam for pediatric conscious sedation.

Midazolam conscious sedation records of pediatric dental patients, one to six years of age, were reviewed retrospectively to: 1) examine the factors associated with the use of oral and nasal routes of administration and their effect on displayed behavior during dental treatment and 2) determine whether a child's compliance with oral administration is predictive of the intraoperative behavior displayed during dental treatment. Two hundred and fifty-seven conscious sedation records for 222 pediatric dental patients sedated with orally or nasally administered midazolam for dental treatment at the University of Florida were reviewed. Data collected included the patient's age, gender, route of administration, dose, compliance with oral administration, appointment type (planned vs. emergency), previous sedation experience with midazolam, operator vs. parent administration of the medication, use of papoose board and nitrous oxide/oxygen inhalation, types of procedures performed (restorations only, extractions only, or both), length of treatment rendered, and preoperative and intraoperative behavioral assessments of the child. The collected data were analyzed with Statview software using ANOVA and Chi-square analyses. There was a statistically significant difference (p < 0.001) between oral and nasal administration for the parameters of age, procedure length, appointment type, procedures performed, previous sedation experience and use of the papoose board and nitrous oxide/oxygen inhalation. While there was no statistically significant influence of chronological age on the preoperative Frankl behavior ratings, there was a statistically significant mean age difference with respect to the administrator of the medication (parent vs. operator), papoose board use, N2O/O2 use and previous sedation experience. Forty-five percent of the subjects were willing to accept oral administration of the medication, however, there was no statistically significant difference (p = 0.114) between the child's compliance to accept the medication and the intraoperative Frankl behavioral ratings displayed during dental treatment. In this review of midazolam conscious sedation records of pediatric dental patients. 1) route of administration was significantly influenced by several patient and procedural variables, resulting in different behavioral outcomes and 2) compliance with oral administration was not predictive of behavior displayed during treatment.

Administration, Intranasal↗
PubMed2002

Determination of arterial baroreflex-blood pressure control in conscious rats.

AIM: To study the determination of arterial baroreflex-blood pressure control (ABR-BP) in conscious rats. METHODS: Blood pressure was continuously recorded with a computerized system in conscious freely moving rats. The principle of ABR-BP measurement is to compare the pressor response to a vasoactive drug (angiotensin II) before and after the interruption of this reflex. RESULTS: (1) ABR-BP values revealed by angiotensin II were closely correlated with those by phenylephrine. Doses of angiotensin II did not influence the results within certain range. (2) ABR-BP was well correlated with arterial baroreflex-heart period control (ABR-HP). (3) Anesthesia inhibited ABR-BP. There existed a circadian variation of ABR-BP in WKY rats. (4) Blood pressure variability was closely related to ABR-BP, but not to ABR-HP. (5) ABR-BP was impaired in hypertensive rats. CONCLUSION: ABR-BP is an important parameter to reflect the function of ABR. The present work makes it possible to determine ABR-BP in conscious rats. ABR-BP plays an important role in maintaining blood pressure stability and it is impaired in hypertension.

Angiotensin II↗
PubMedDate not supplied

The effects of oral conscious sedation on future behavior and anxiety in pediatric dental patients.

PURPOSE: This study investigated the relationship between oral conscious sedation and subsequent behavior in the dental setting. METHODS: The sample consisted of 38 children between the ages of 39 to 71 months (mean=50 months) who had been treated with oral sedation 2 to 34 months(mean=13 months) previously, and a control group of 38 children, matched by age (mean=51 months) and gender, who had received dental treatment without conscious sedation or general anesthesia one week to 3 years previously. Subjects were matched by age and gender. All children received a standard recall examination and a prophylaxis, during which behavior and anxiety were measured. Independent variables included age at the time of sedation, present age, gender, time elapsed since sedation, effectiveness of sedation, parental scores on Corah's Dental Anxiety Scale and parent's answers to a questionnaire. The dependent variables were child behavior (rated with the 4-point Frankl scale) and self-reported anxiety ratings. RESULTS: Both groups had mean behavior ratings of positive or very positive (experimental group mean=3.13; control group mean=3.34). There were no statistically significant differences between the groups and there was little correlation of independent and dependent variables. CONCLUSIONS: There is no relationship between oral conscious sedation and the future behavior of children in the dental setting.

Anesthesia, Dental↗
PubMed1999

Comparison of Cardiovascular Parameters and/or Serum Chemistry and Hematology Profiles in Conscious and Anesthetized Rhesus Monkeys (Macaca mulatta).

The rhesus monkey is often used in pre-clinical research, and such studies frequently involve a variety of anesthetic conditions. Therefore, it is important to determine baseline physiologic blood chemistry and cardiovascular parameters in anesthetized animals to facilitate appropriate comparisons. The present study compares the cardiovascular parameters, hematology, serum chemistry, and blood gas levels of rhesus monkeys anesthetized with pentobarbital, isoflurane, ketamine, and propofol. Hematology, serum chemistry, and blood gas levels were unaffected by the four anesthetic regimens. However, because of its formulation, propofol is inappropriate for use in animals in which changes in tryglycerides will be evaluated. Compared to those in conscious, unrestrained monkeys, heart rates were higher in anesthetized animals, but the rates of anesthetized animals were similar regardless of anesthetic agent used. In contrast, mean arterial blood pressure was lower in animals anesthetized with pentobarbital, propofol, or isoflurane than in the conscious monkeys. However, mean arterial pressure of ketamine-anesthetized monkeys was similar to that of the conscious monkeys.

Journal Article↗
PubMed2002

A placebo-controlled, randomized trial of droperidol versus metoclopramide for outpatients undergoing gynecological laparoscopy under conscious sedation.

This study compared the prophylactic antiemetic efficacy and the adverse effects of 0.5 mg droperidol, 5.0 mg metoclopramide, and placebo for outpatients undergoing gynecological laparoscopy under conscious sedation. One hundred and fifty outpatients were randomly allocated, in a randomized double-blind manner, into three groups to receive intravenous normal saline, 0.5 mg droperidol, and 5.0 mg metoclopramide before operation. Conscious sedation using intravenous pethidine, midazolam and local infiltration were given to each patient during the operation. Emetic symptoms were graded twice by the patients, at discharge time and the 24th post-operative hour. The difference of antiemetic effect of both study drugs failed to reach statistical significance. There was also no statistical difference of intra-operative hypoxemia, sedation score, and discharge time among the groups. Therefore, using 0.5 mg droperidol or 5.0 mg metoclopramide is not effective in providing antiemetic prophylaxis for outpatients undergoing gynecological laparoscopy under conscious sedation.

Adolescent↗
PubMed2003

[A patient with an unexplained loss of consciousness: a case for the neurologist or the cardiologist?].

Three patients, a woman aged 62 and two men aged 22 and 77 years respectively, were admitted because of an unexplained loss of consciousness. In the woman and younger man these complaints were caused by a vasovagal reaction, and in the older man by hypersensitivity of the carotid sinus. In a hospital setting, the examination of patients with a loss of consciousness often leads to discussions between the neurologist and the cardiologist. Elaborate additional testing seldom reveals epilepsy or cardiac arrhythmia as the cause. A thorough medical history can exclude both diagnoses in almost all cases. Physicians should be aware that most patients experience a vasovagal syncope and that this might be triggered by very common circumstances. Knowledge of these triggers and the epidemiology of loss of consciousness might prevent the patients from being examined by different specialists and undergoing unnecessary additional tests.

Adult↗
PubMed2003

[Initial diagnostic strategy in the case of transient losses of consciousness: the importance of the medical history].

It is estimated that almost half of the people experience a transient loss of consciousness at some time during their life. In young patients (< 35 years) the cause is mostly a reflex syncope. In older patients the common causes are orthostatic and postprandial hypotension, sinus caroticus syndrome, cardiac arrhythmias and valvular disorders. The medical history can identify a probable cause of the transient loss of consciousness in almost all young patients (< 35 years) and in the majority of older patients. A physical examination and an ECG should be performed in all patients who have experienced a transient loss of consciousness, other than those with classical vasovagal syncope, in order to exclude orthostatic hypotension and dangerous cardiac causes.

Adult↗
PubMed2002

Clinical recovery time from conscious sedation for dental outpatients.

For dental outpatients undergoing conscious sedation, recovery from sedation must be sufficient to allow safe discharge home, and many researchers have defined "recovery time" as the time until the patient was permitted to return home after the end of dental treatment. But it is frequently observed that patients remain in the clinic after receiving permission to go home. The present study investigated "clinical recovery time," which is defined as the time until discharge from the clinic after a dental procedure. We analyzed data from 61 outpatients who had received dental treatment under conscious sedation at the Hiroshima University Dental Hospital between January 1998 and December 2000 (nitrous oxide-oxygen inhalation sedation [n = 35], intravenous sedation with midazolam [n = 10], intravenous sedation with propofol [n = 16]). We found that the median clinical recovery time was 40 minutes after nitrous oxide-oxygen sedation, 80 minutes after midazolam sedation, and 52 minutes after propofol sedation. The clinical recovery time was about twice as long as the recovery time described in previous studies. In a comparison of the sedation methods, clinical recovery time differed (P = .0008), being longer in the midazolam sedation group than in the nitrous oxide-oxygen sedation group (P = .018). These results suggest the need for changes in treatment planning for dental outpatients undergoing conscious sedation.

Adolescent↗
PubMed2000

Does brief loss of consciousness affect cognitive functioning after mild head injury?

Loss of consciousness often is considered an important variable when estimating head injury severity. The purpose of this study was to determine if brief loss of consciousness had any effect on the neuropsychological test performance of patients in acute recovery from an uncomplicated mild head injury (N = 195). Three groups of 65 patients were given a brief battery of neuropsychological tests within one week of sustaining a mild head injury. The groups, sorted on the basis of loss of consciousness (i.e., positive, negative, or equivocal), did not differ in age or education. There were no significant differences among the groups on any of the measures of attention, learning, memory, language, or executive functioning.

Journal Article↗
PubMed2002

Changes of intracranial pressure during head-down tilt in anesthetized and conscious rabbits.

Effects of head-down tilt on intracranial pressure were studied in anesthetized and conscious rabbits. Adult Japanese white rabbits of both sexes, weighing 2.5-3.5 kg, were used in the experiments. Experiment 1. Animals were anesthetized with pentobarbital, and ICP was monitored through a catheter inserted into the subarachnoid space. ICP elevated immediately after the onset of 45 degrees HDT and gradually reduced toward the baseline level in the next 8 hours. Experiment 2. Each rabbit was exposed to 45 degrees HDT for 24 hours and the ICP was measured through a catheter which had been implanted 7 days before. In the conscious rabbits, ICP increased about 4 mmHg after the onset of 45 degrees HDT, further increased gradually to the peak at 11 hours of HDT, and then started to return to the baseline. These results suggest that the time course of the change in ICP during HDT is considerably different between anesthetized and conscious rabbits.

Comparative Study↗
PubMed2004

[Usefulness of conscious sedation with midazoram during transesophageal echocardiographic examination].

OBJECTIVES: Although transesophageal echocardiography is useful to identify various cardiovascular diseases, the semi-invasive nature of the examination hampers its routine application. We investigated whether conscious sedation using a low dose of intravenous midazoram was safe and useful during the examination. METHODS: We asked 55 consecutive patients undergoing transesophageal echocardiography (44 with midazoram, mean age 59 +/- 16 years, and 11 without midazoram, mean age 62 +/- 8 years) and the examiners about the effects of midazoram using a questionnaire. RESULTS: The mean dose of midazoram was 2.2 mg (range 1-3.5 mg). All examinations were done without any adverse events. Eighty-two percent of the patients with midazoram considered the examination under conscious sedation tolerable, whereas 91% without midazoram felt it untolerable. Most examiners felt manipulation of the echo probe was easier in patients with midazoram than in those without (69% vs 27%). CONCLUSIONS: Conscious sedation with a low dose of intravenous midazoram facilitated and increased patient tolerance during transesophageal echocardiographic examination.

Aged↗
PubMed2004

The vegetative and minimally conscious states: consensus-based criteria for establishing diagnosis and prognosis.

Disorders of consciousness continue to be the subject of hot debate in healthcare settings, research consortiums, bioethics departments and media forums. There are no standards of care to guide assessment and treatment decisions resulting in wide disparities in daily practice. In response to this problem, expert panels in neurology and neurorehabilitation were convened and charged with developing consensus-based definitions and diagnostic criteria for disorders of consciousness. The Multi-Society Task Force Report on the persistent vegetative state and the Aspen Workgroup statement on the minimally conscious state represent two such initiatives. This paper summarizes the practice recommendations proposed by these groups and discusses their implications for existing and future interventions.

Humans↗
PubMed2005

EEG correlates of G-induced loss of consciousness.

INTRODUCTION: Electroencephalographic (EEG) correlates of Gz-induced loss of consciousness (G-LOC) were examined to better understand the mechanisms of G-LOC. METHODS: There were 10 subjects (4 women) who provided 35 G-LOC episodes during which 13 channels of EEG and eye activity were recorded. Subjects simultaneously performed tracking and mathematical tasks prior to and following G-LOC. The performance data and cerebral regional oxygen saturation (rSO2), as measured using near infrared spectroscopy, were correlated with the EEG changes. RESULTS: Across all subjects, seven EEG events were identified and measured. The two most significant were found over widespread scalp sites. They were a 1-2 Hz waveform just prior to G-LOC and a very large, approximately 1 Hz waveform just prior to regaining consciousness. These were associated with a drop of rSO2 levels to approximately 90% of the pre-G-LOC baseline levels. rSO2 levels returned to pre-G-LOC levels within approximately 15 s following G-LOC while EEG and performance measures took approximately 60 s. DISCUSSION: There were two unique EEG waveforms found, one preceding unconsciousness and the other preceding the return to consciousness during G-LOC episodes. Further, the supply of oxygen to the brain was rapidly restored, within approximately 15 s, while the EEG and performance data showed that approximately 60 s were required for the brain to regain functional integrity. The delay in performance and EEG recovery following G-LOC demonstrates that the recovery of brain activity to support cognitive function requires more than just the restoration of normal oxygen levels.

Adult↗