Some quantitative EEG features in default mode resting state network under general anaesthesia.

OBJECTIVES: The default mode resting state network (DMRSN) constitutes a circuit which is active in conditions when the subject is at rest. We tested the hypothesis that its function will be altered during unconsciousness. METHODS: Changes in the mean squared coherences in five conventional frequency bands (delta to gamma) in DMRSN during general anaesthesia (GA) were investigated in 39 patients. They were compared with the normal EEG of 86 alert subjects, severely abnormal EEG of 112 patients with dementia and/or encephalopathy, and the mathematical model of brain death. RESULTS: Anaesthetised patients showed significant decrease in the gamma coherence in the posterior area of the DMRSN compared to both the control group and the patients with dementia and/or encephalopathy. Among the anaesthetized patients 21 had a clear burst suppression pattern with prolonged epochs of suppression in EEG. In suppressed EEG segment the differences between the connections of the anterior to posterior parts and connections between the posterior parts of the DMRSN were almost lost. However, they still showed highly significant differences in most items when compared with coherences in the mathematical model of brain death. CONCLUSION: The functional connectivity in the DMRSN could be a reliable and robust method for assessing the depth of anaesthesia and maybe also disorders of consciousness in general. The mean squared coherences in the gamma frequency band indicated the highest sensitivity for the depth of unconsciousness. The measure is not dependent on the diffused slowing in dementia or encephalopathy patients as long as they remain in a full consciousness.

Prefrontal left--dominant hemisphere--gamma and delta oscillators in general anaesthesia with volatile anaesthetics during open thoracic surgery.

OBJECTIVES: The main objective was to indicate sufficient general anaesthesia (GA) inhibition for negative experience rejection in GA. PATIENTS AND METHODS: We investigated the group of patients (n = 17, mean age 63.59 years, 9 male--65.78 years, 8 female - 61.13 years) during GA in open thorax surgery and analyzed EEG signal by power spectrum (pEEG) delta (DR), and gamma rhythms (GR). EEG was performed: OPO - the day before surgery and in surgery phases OP1-OP5 during GA. Particular GA phases: OP1 = after pre- medication, OP2 = surgery onset, OP3 = surgery with one-side lung ventilation, OP4 = end of surgery, both sides ventilation, OP5 = end of GA. pEEG registering in the left frontal region Fp1-A1 montage in 17 right handed persons. RESULTS: Mean DR power in OP2 phase is significantly higher than in phase OP5 and mean DR power in OP3 is higher than in OP5. One-lung ventilation did not change minimal alveolar concentration and gases should not accelerate decrease in mean DR power. Higher mean value of GR power in OPO than in OP3 was statistically significant. Mean GR power in OP3 is statistically significantly lower than in OP4 correlating with the same gases concentration in OP3 and OP4. CONCLUSION: Our results showed DR power decreased since OP2 till the end of GA it means inhibition represented by power DR fluently decreasing is sufficient for GA depth. GR power decay near the working memory could reduce conscious cognition and unpleasant explicit experience in GA.

Incidence of skeletal muscle disorders after statins' treatment: consequences in clinical and EMG picture.

OBJECTIVES: The goal of this clinical trial was to determine the incidence of undesirable side effects, and to ascertain any occurrence of genetic polymorphisms. MATERIAL AND METHODS: Clinically, we looked for manifestations of a benign myositis and of serious rhabdomyolysis. We observed a group 198 patients treated with statins, primarially fluvastatin and rosuvastatin. There were 126 (mean age = 58.3 ± 4.1; male 91, mean age = 57.4 ± 5.9; female 35, mean age = 60.5 ± 6.5) patients in a subgroup where we administered rosuvastatin. Undesirable muscular signs and symptoms were present in 32 patients (25.39%). In 11 (8.73% of the total 126) CK level increased maximally to 4 times ULN, in 6 (4.7%) statins were excluded because of very intense subjective suffering. CK levels 2-5 times ULN were present in 9 (7.14%). CK blood levels over 10 times ULN or higher indicated statins exclusion in 2 (1.58%). Increased levels of the further muscular enzyme AST by 5 times ULN were present in 16 (12.69%), up to 10 times ULN in 2 (1.58%), and over 10 times ULN also in 2 (1.58%). RESULTS: We observed rhabdomyolysis in 6 patients (3.03% of the total 198 patients group) using other types of statins (three of them undergo chronic hemodialysis). In this group we performed molecular-genetic analysis of the following proteins relating to statin myopathy: SLCO1B1(388AA/AG-521TT) - (discovered polymorphism in 1 patient), further cytochroms Cyp 2C9 (in 1 patient), 2C8 (in 1 patient), Cyp SA/4 (non discovered positivity) and finally UGT1A1*2B (discovered in 2 patients). CONCLUSIONS: In the group of patients treated by rosuvastatin, we discovered not one case of rhabdomyolysis. In each patient with rhabdomyolysis (brown urine discoloration, mal-odorous urine, painful muscle cramps, muscle weakness, fatigue) at least one polymorphism of "statins´ genes" was present.

Acute consciousness disorders in intensive care medicine - value of its grading for prognostic conclusion.

OBJECTIVES: To understand consciousness we have to understand the mechanism of its function, which is to effectively organize sensory inputs from our environment. Consciousness is the basic, essential outcome of the process of organizing these sensory inputs, resulting in cognitive, mental, emotional, executive, instinctual or other marginally aware states. This reciprocal process of the CNS implies that organization is an act, which precedes consciousness, i.e. preconscious function. Most scientific explanations portray consciousness as an "emergent property" of classical computer-like activities in the brains neural networks. Doctors at ICU work daily with patients with altered human consciousness. Therefore, they must recognize and manage it skilfully and use adequate approaches for definite solutions. MATERIAL AND METHODS: We observed a series of patients with traumatic and non traumatic brain injuries admitted to the ICU. The quality of life of these patients during the course of intensive care was very elementary and the final outcome GCS (oGCS) for future life was defined as a comatose state or apallic state, very rarely was it restored to premorbid condition as far as lucidity, attention, cognition, and executive functions. RESULTS: We found that a significant oGCS increase in relation to condition at admission or intake GCS (iGCS) in the group with 184 patients total (p<0.00001), in cardio-pulmonary resuscitation (CPR), traumatic brain injury (TBI) subgroups (p<0.00001) and in spontaneous haemorrhage (SH) (p<0.05) represents the only basic prerequisite for further improvement. It is not easy to find good therapeutic approaches after traumatic and non traumatic brain injury. A statistically significant oGCS increase in relation to iGCS due to quite intense medical care and keeping disclosed the state of unconsciousness with further probable evolution through the following possible ways: death in fluent comatose state, delirium and awakening, delirium ending in death, direct awakening from comatose state. Therefore significantly increased oGCS is the only basic prerequisite for pragmatically optimal "quality of life" in the course of later life. CONCLUSION: We raise general questions for both scientists and clinicians that will assist in their efforts to understand the basic endogenous conscious biological processes, their pathological changes and the links between them.

Delirium and postoperative cognitive dysfunction after general anesthesia.

BACKGROUND: General anesthesia is characterized by unconsciousness, analgesia, muscle relaxation, and depression of reflexes, generally in response to the administration of chemical agents that induce reversible unconsciousness. Study of the cognitive neuroscientific basis of general anesthesia involves evaluation of the effect of anesthetic agents on consciousness and the brain mechanisms underlying cognitive function. Central nervous system dysfunction after anesthesia and/or surgery can occur at any age but is a particular issue for elderly patients. Studies of delirium and postoperative cognitive dysfunction have been published in many countries since the end of the last century. We present a discussion of delirium disorders and a review of the literature. CASE REPORT: We also present case reports for 2 patients who underwent general surgery for epilepsy. The first patient experienced postoperative visual illusions, hallucination, and time and space disorientation. The second patient experienced a postoperative zombie-like delirium state. The status of both patients was improved in response to treatment with methylprednisolone. The first patient also received amantadine sulfate, and the second patient received antiepileptic drugs. CONCLUSIONS: The brain is the main target organ for anesthetic and adjuvant drugs, and age-associated changes in the brain have important implications with respect to general anesthesia. Anesthetists and surgeons have suspected for many years that some patients suffer a postoperative decline in cognitive function. The condition generally has a good outcome because oxidative nerve cell derangements and neurotransmitter imbalances are transient.

Vestibulo-ocular (oVEMP) responses produced by bone-conducted sound stimuli applied to the mid-sagittal plane of the head.

Recently several studies have yielded evidence that impulses of bone-conducted (BC) sound can produce short-latency myogenic responses in the extraocular muscles, which are probably mediated by otolithic afferents. These responses, although miniscule, can be recorded with surface electrodes and are termed ocular vestibular evoked myogenic potentials (oVEMP). It is assumed that in response to low-frequency BC-sound stimuli the head moves predominantly along the axis from the site of the applied stimulus to the opposite side. Thus, oppositely-directed accelerations along a particular axis would produce oppositely-directed compensatory vestibulo-ocular responses (VOR) and oVEMPs. The aim of this study was to investigate whether the oVEMPs would reflect these direction-dependent VOR responses. Single cycles of 125 and 250 Hz BC tones were applied to opposite sides of two approximately orthogonal, naso-occipital (x) and vertical (z) axes of the head. oVEMP responses were recorded with standard bilateral vertical EOG montages. The responses in all twelve healthy subjects showed consistent differences with regard to the latency and/or shape of the response to stimuli applied to opposite sides of the head. These differences likely reflect different patterns of electro-myographic activity of the extraocular muscles, which may be mediated by groups of vestibular (probably otolithic) afferents with differently-orientated spatial polarization vectors.