Consciousness and general anaesthesia: a recent view.

An explanation of consciousness is one of the major unsolved problems of modern science. The modern view of consciousness arose in the nineteenth century; the view presumed that mental activity correlates with distinct physical states. Is the problem of consciousness real? Crick and Koch made a tentative assumption that all different aspects of consciousness (pain, seeing, thinking, emotion, self-consciousness) are connected by a basic common mechanism. The next step towards understanding involved the neuronal theories of consciousness (correlates of consciousness), often referred as the NNC (neural correlates of consciousness). Many neuroscientists presume that consciousness must have a neuronal correlate. The neuroscience of anaesthesia can be defined as studying the effect of anaesthetic agents on consciousness and the preconsciousness brain mechanisms of cognitive function. Some of these mechanisms, such as recognition of the novel stimuli, are still present in deep anaesthesia, during continuous suppression. Anaesthesia is not "an all or nothing" phenomenon and consciousness awareness with explicit memory represents only one part of the spectrum of cognitive functions. The introduction of safe general anaesthesia represents one of the most important, although under-appreciated, advances in modern surgery. There is some difficulty in defining the term "consciousness" in relation to the anaesthetic state. The difference in brain activity between those under anaesthesia and those not under any such influence.

Comparison of postsurgical and community acquired bacterial meningitis--analysis of 372 cases within a nationwide survey.

The aim of this study was to assess if differences in etiology and risk factors among 372 cases of bacterial meningitis acquired after surgery (PM) or in community (CBM) have impact on outcome of infected patients. Among 372 cases of bacterial meningitis within last 17 years from 10 major Slovak hospitals, 171 were PM and 201 CBM. Etiology, risk factors such as underlying disease, cancer, diabetes alcoholism, surgery, VLBW, ENT infections, trauma, sepsis were recorded and mortality, survival with sequellae, therapy failure were compared in both groups. Significant differences in etiology and risk factors between both groups were reported. Those after neurosurgery had more frequently Coagulase negative staphylococci (p<0.001), Enterobacteriaceae (p=0.01) and Acinetobacter baumannii (p=0.0008) isolated from CSF and vice versa Streptococcus pneumoniae (p<0.001), Neisseria meningitis (p<0.001) and Haemophillus influenza (p=0.0009) were more commonly isolated from CSF in CBM. Neurosurgery (p<0.001), sepsis (p=0.006), VLBW neonates (p=0.00002) and cancer (p=0.0007) were more common in PM and alcohol abuse (p<0.001) as well as otitis/sinusitis (p<0.001) and Roma ethnic group (p=0.001) in CAM. Initial treatment success was significantly more frequently observed among CAM (p<0.001) but cure after modification was more common in PM (p=0.002). Therefore outcome in both groups was similar (14.6% vs. 12.4%, p=NS).

Biochemical and clinical improvement of cytotoxic state by amantadine sulphate.

1. The main idea of the open clinical trial was to compare the income and outcome clinical picture and the evolution of the biochemical markers in the defined intervals in closed head injury group patients. 2. In the group of 32 patients, mean age 40.78+/-15.36 years suffering from closed traumatic brain injury the following markers were measured: glycaemia, malondialdehyde (MDA) as marker of lipid peroxidation, beta-caroten, total SH groups as marker of protein oxidation in the following intervals: between the 1st and the 3rd, between the 3rd and the 7th, between the 1st and the 7th day respectively. 3. Glycaemia significantly decreased since the 1st day till the 3rd day (p < 0.05) and since the 1st day till the 7th day (p < 0.05) but it was not significantly changed since the 3rd day till the 7th day (p > 0.05). 4. MDA 1st x MDA 3rd p > 0.05 insignificant change, MDA 1st x MDA 7th p < 0.001--high significant decrease, MDA 3rd x MDA 7th--p < 0.0001--very high significant decrease. 5. Beta-caroten the 1st x beta-caroten the 3rd day was insignificantly changed-p > 0.05, the 3rd x the 7th day beta-caroten increased significantly--p < 0.0002, the 1st day x 7th day beta-caroten significantly increased--p < 0.0001. 6. We examined the SH groups only in nine patients, due to technical problems and SH groups decrease on the 3rd day (p < 0.005). 7. In 18 amantadine sulphate subgroups (randomly selected), there was 5.5% lethality and mean outcome GCS (outGCS) 9.83+/-3.8, while lethality of the control subgroup (n=14) was 42.9%, mean outGCS 6.28+/-3.5.

The outcome of patients with severe head injuries treated with amantadine sulphate.

OBJECTIVE: To compare our pilot therapeutic results of patients with severe head injury treated either with standard therapy alone or with standard therapy plus amantadine sulphate. DESIGN: Retrospective pilot study. SETTING: Intensive Care Unit (ICU), University Hospital. PATIENTS: All patients with severe head injury (GCS < 8) admitted to the ICU between January 1, 1999 and December 31, 2001. The patients were divided into two groups based on the fact, whether they did or did not receive amantadine sulphate included in standard therapy. Group 1 consisted of 41 patients of average age 42.12 +/- 16.8 years, of them 35 were males and 6 females. Group 2 included 33 patients of average age 43.91 +/- 18.45 years consisting of the 30 males and 3 females. INTERVENTION: Both groups were treated with the standard therapy of severe head injury accepted in our institution. In addition, group 1 patients received amantadine sulphate in a dose of 200 mg i.v. twice daily for 3 days, starting on day 3 of hospitalisation. The reason for amantadin sulphate administration was persistent comatos condition. MEASUREMENTS AND RESULTS: Glasgow Coma Scale in patients on admission (after resuscitation) and on discharge from the ICU and mortality rate were compared. In the group 1 the average income GCS was 4.47 +/- 2.26 and the average outcome GCS was 9.76 +/- 3.95. In the group 2 the average income GCS was 4.70 +/- 2.14 and the average outcome GCS was 5.73 +/- 3.57. In the amantadine sulphate group two patients out of 33 died (6.06%). There were 17 deaths (51.51%) out of 33 patients in the second control group. CONCLUSION: In the group of patients with severe brain injuries treated with standard therapy plus amantadine sulphate the outcome GCS was higher and the case fatality rate lower than in the group treated with standard therapy alone.

[Pharmacologic cytoprotection of the central nervous system]. / Farmakologická cytoprotekcia CNS.

Ischaemia of the central nervous system is considered to be a phenomenon, which manifests after the ischaemic episode and has limited therapeutic possibilities. Clinical situations in which the oxygen supply may be reduced include the following: stroke and transient ischaemic attacks, subarachnoid haemorrhage before, during and after carotid artery surgery, prolonged cardiopulmonary bypass during heart surgery, head injuries, cardiac arrest: (during arrest and recirculation), aortic surgery, spinal cord ischaemia, severe hypoxia/hypoxaemia, severe hypoperfusion/shock conditions. Although these clinical conditions are markedly different, they share the major similarities of cell death and its pathophysiology and pathogenesis, to which lies the therapy of CNS ischaemia is aimed. New cytoprotective drugs for neuronal damage are lazaroids. The 21-aminosteroids are known as inhibitors of lipid membrane peroxidation which preserve post-injural Ca2+ homeostasis (after total and focal ischaemia). During the last few years evidence has been accumulated about CCAs brain protection against cerebral ischaemia by a virtue of direct neuronal action. The excitatory amino acid antagonists, barbiturates, corticosteroids, antiepileptic drugs and antioxidants complete the cytoprotective treatment possibilities in situations of reduced oxygen supply for CNS. (Ref. 17.)

[Memory, awareness and learning in general anesthesia]. / Pamät, uvedomovaná bdelost a ucenie v celkovej anestézii.

Enough information concerning memory and other cognitive functions in total anesthesia is available in the literature. Some basic theories about neuronal mechanisms of memory and consciousness are known. An attempt trying to bridge the gap between psychological and biologic levels is the usage of anesthetics in pharmacologic tests enabling the study of their influence on awareness and memory in humans. With the help of this approach it is possible to inquire into the psychological mechanisms and to demonstrate the influence of anesthetics on them. 44 patients were included in the study, operated on in inhalation anesthesia. The effects of anesthesia on awareness, consciousness, learning and memory in our study sample were following: 1. No episode of awareness was observed during the study; 2. There was an improvement of the memory quotient (MQ) following total inhalation anesthesia (p < 0.05); 3. The pain threshold significantly decreased after anesthesia (p < 0.001); 4. There exists a learning mechanism in total anesthesia more efficient in the group of patients auditively learning pain related words (p < 0.05) comparing to the control group of patients auditively learning pain nonrelated words; 5. Statistical analysis of the number of remembered pain related words and pain nonrelated words revealed significantly higher number of words in the first group of pain related words (p < 0.001). (Tab. 3, fig. 6, Ref. 22.)

[Tirilazad mesylate (Freedox)--an effective inhibitor of lipid membrane peroxidation]. / Tirilazad Mesylate (Freedox) úcinný inhibítor peroxidácie lipidov bunkovej membrány.

The 21-aminosteroids (lazaroids) are inhibitors of lipid membrane peroxidation and appear to function as reactive free radical scavengers (RFRS). Freedox--a multimechanistic cytoprotective inhibitor of lipid peroxidation has been developed specifically to minimize secondary tissue damage. It is the first lazaroid compound used in clinical practice for critical care indications. Structurally described as a 21-aminosteroid, it has no glucocorticoid, mineralocorticoid, or other hormonal effects. Cytoprotective pathways of Freedox after its insertion into the lipid bi-layer of cell membrane include: scavenging reactive oxygen intermediates (ROI), stabilizing cell membrane by decreasing fluidity, preserving vitamin E content in membrane, increasing surface viscosity, preserving of post injury Ca+2 homeostasis. There was shown its efficacy in improving neurologic outcome following CNS trauma, subarachnoid hemorrhage, and ischemia. The therapeutic potential of the lazaroid Freedox has been extensively studied in several CNS disorders. There is an increasing experimental and clinical evidence about the oxygen free radical formation and cell membrane lipid peroxidation which play an important role in the pathogenesis of subarachnoid hemorrhage, spinal cord trauma, head injury and inflammatory processes of the NS. Freedox has also been tested in a variety of stroke models. (Fig. 1, Ref. 19.)

[Nociception and mental functions after combined neuroleptanalgesia]. / Nocicepcia a niektoré psychické funkcie po kombinovanej neuroleptanalgéze.

In a group of 25 patients divided at random into subgroups anaesthetized by neuroleptoanalgesia or ataralgesia resp. on account of arthroscopy, the authors assessed the state of mental functions--perception, memory before, and after operation, emotional make-up, affectivity, cognitive functions and some personality parameters. By means of an algometer and the cuff of a manometer they assessed the threshold of pressure and ischemic pressure pain. They found that in no instance intraoperative experience appeared, the threshold of nociceptive pressure perception was considerably reduced after operation in both groups. The threshold of ischemic pressure pain was significantly reduced only in the group with Hb greater than 150 and Le greater than 8.0, anaesthetized by neuroleptanalgesia. A significant increase of the depressivity (5%) was recorded in the group with combined neuroleptoanalgesia. Dysphoria and emotional indifference increased (5%) in the group with neuroleptanalgesia. Within 2-4 hours after termination of anaesthesia significant consolidation of long-term memory occurred, whereby short-term memory did not display any changes in either group i.e. regardless of the type of anaesthesia. Attention was significantly improved after both types of anaesthesia, but more markedly after neuroleptanalgesia. In the group with combined neuroleptanalgesia sensory and neurasthenic complaints improved (5%). The degree of experienced fear and anxiety in conjunction with the operation as well other psychic parameters before operation were equal in both groups and the groups were thus equivalent. In relation to the plasma cortisol level (degree of preoperative stress) there was a close correlation between the emotional lability on the one hand and maladaptation on the other. The degree of preoperative stress created a close correlation between fear and maladaptation on the one hand and frightening experience on the other.