[Fractal dimension--a new EEG-based method of assessing the depth of anaesthesia]. / Próba wykoraystania analizy sygnalów EEG metoda wymiaru fraktalnego do okreslania stopnia zniesienia swiadomosci podczas indukcji znieczulenia ogólnego.

BACKGROUND: It has been suggested that analysis of the EEG signal using the fractal dimension method may be useful for assessment of depth of anaesthesia. METHODS: Thirty ASA I and II patients, scheduled for elective surgery under general anaesthesia were induced with midazolam, fentanyl and propofol and paralyzed with rocuronium or cis-atracurium. Clinical signs of the depth of anaesthesia were classified to one of five OAA/S levels. Standard vital parameters were observed and brain electrical activity was measured using the bispectral index (BIS) and burst suppression ratio (BSR). The EEG signal was recorded and processed postoperatively to calculate Higuchi's fractal dimension (FD). The latter was presented as a derivative: (D(F)-1) x 100. RESULTS: Mean correlation coefficients between OAA/S scale levels, and BIS and (D(F)-1) x 100 values, were respectively: 0.749+/-0.172 and 0.753+/-0.220. In 28 (93.3%) patients, BIS correlated well with FD (r=0.63+/-0.33). In twenty cases, burst suppression occurred and the correlation coefficient between BIS and DF was much lower (r=0.5860+/-3650), when compared to the group of 10 patients in which no burst suppression was detected (r=0.711+/-0.251). Appropriate correction was made using the following formula: D(FK)=D(F)-(D(F) x BSR). The mean correlation coefficient between BIS values and D(FK) in the BS group was r=0.629+/-0.331. In all cases, the mean correlation coefficient between (D(F)-1) x 100 and BIS was r=0.661+/-0.307 (p<0.001). CONCLUSIONS: The fractal dimension method can be regarded as equal to BIS for assessment of depth of anaesthesia.

Abnormally low bispectral index and isoelectric electroencephalogram observed after administration of small doses of propofol during induction of anesthesia.

We describe a case in which an unexpectedly, abnormally low bispectral index value (BIS = 4) and an almost isoelectric electroencephalogram (EEG) pattern were observed during typical induction of anesthesia with propofol. Starting 2 min after the beginning of propofol administration (1.26 mg kg(-1)), the EEG recordings showed burst and suppression pattern for the next 12 min. The EEG during this period was characterized by gradual prolongation of suppression periods until the appearance of the isoelectric line. After that, burst activity returned and eventually the burst suppression pattern disappeared. We excluded the possibility of ischemic brain damage, and the evidence increasingly points toward a greater sensitivity to propofol. The findings described in this case report support the thesis that there is a wide variability in the responses of patients to propofol that cannot be detected without continuous monitoring of cortical electrical activity.

Sole use of dexmedetomidine has limited utility for conscious sedation during outpatient colonoscopy.

BACKGROUND: This study evaluated the ability of dexmedetomidine to provide analgesia and sedation for outpatient colonoscopy, examining outcomes including cardiorespiratory variables, side effects, and discharge readiness. METHODS: Sixty-four patients were randomly assigned to one of three treatment regimens. In group D, patients received 1 microg/kg dexmedetomidine over 15 min followed by an infusion of 0.2 microg x kg x h. Group P received meperidine (1 mg/kg) with midazolam (0.05 mg/kg), and group F received fentanyl (0.1-0.2 mg intravenous) on demand. The assessment included measurements of heart rate, blood pressure, oxygen saturation, respiratory rate, quality of sedation/analgesia, and an evaluation of the recovery time. RESULTS: The study was terminated before the planned 90 patients had been recruited because of adverse events in group D. In all groups, negligible hemoglobin oxygen saturation and respiratory rate variations were observed. In group D, there was a significantly larger decrease in heart rate (to approximately 40 beats/min in 2 of 19 cases) and blood pressure (to less than 50% of the initial value in 4 of 19 patients). Supplemental fentanyl was required in 47% of patients receiving dexmedetomidine to achieve a satisfactory level of analgesia (vs. 42.8% of patients in group P and 79.2% of patients in group F). Vertigo (5 patients), nausea/vomiting (5 patients), and ventricular bigeminy (1 patient) were observed only in group D. Time to home readiness was longest in group D (85 +/- 74, 39 +/- 21, and 32 +/- 13 min in groups D, P and F, respectively; P = 0.007). CONCLUSIONS: The use of dexmedetomidine to provide analgesia/sedation for colonoscopy is limited by distressing side effects, pronounced hemodynamic instability, prolonged recovery, and a complicated administration regimen.

Survival after out-of-hospital cardiac arrests in Katowice (Poland): outcome report according to the "Utstein style".

The purpose of this study was to evaluate the outcome of out-of-hospital cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) in the city of Katowice, Poland, during a period of 1 year prior to the planned reorganization of the national emergency system. Data were collected prospectively according to a modified Utstein style. To ensure accurate data collection, a special method of reporting resuscitation events with the use of a tape-recorder was introduced. Patients were followed for a 1-year period. Between 1 July 2001 and 30 June 2002, out-of-hospital cardiac arrest was confirmed in 1153 patients. Cardiopulmonary resuscitation was attempted in 188 patients. Cardiac arrest of presumed cardiac aetiology (147) was bystander witnessed in 105 (71%) cases and lay-bystander basic life support was performed in 35 (24%). In the group of bystander witnessed arrest ventricular fibrillation (VF) or tachycardia was documented in 59, asystole in 40 and other non-perfusing rhythms in six patients. Of 147 patients with cardiac aetiology, return of spontaneous circulation (ROSC) was achieved in 64 (44%) patients, 15 (10%) were discharged alive and 9 (6%) were alive 1 year later. Most of these patients had a good neurological outcome. Time to first defibrillatory shock was significantly shorter for survivors (median 7 min) compared to non-survivors (median 10 min). The most important resuscitation and patient characteristics associated with survival were VF as initial rhythm, arrest witnessed, and lay-bystander CPR.

Conscious analgesia/sedation with remifentanil and propofol versus total intravenous anesthesia with fentanyl, midazolam, and propofol for outpatient colonoscopy.

BACKGROUND: This study tested the hypothesis that, for colonoscopy, analgesia/sedation with remifentanil and propofol might be more effective compared with anesthesia by intravenous administration of midazolam, fentanyl, and propofol. METHODS: In a prospective, randomized trial, 100 adult patients received either conscious analgesia/sedation (Sedation group) or total intravenous anesthesia (TIVA group). Analgesia/sedation was achieved by infusion of remifentanil (0.20 to 0.25 microg/kg/min) and propofol in titrated doses. TIVA was induced by intravenous administration of fentanyl (2 microg/kg), midazolam (0.05 mg/kg) and propofol (dosage titrated). Cardiorespiratory parameters and bispectral index were monitored and recorded. The quality of the analgesia was assessed with a Numerical Pain Rating Scale (NRS); recovery level and return of psychomotor efficiency were evaluated with, respectively, the Aldrete scale and a Modified Post Anesthesia Discharge Scoring (MPADS) system. RESULTS: Both groups of 50 patients were comparable with respect to demographic data, initial parameters, and duration of colonoscopy. All patients in the TIVA group found the colonoscopy painless (NRS score 0). In the Sedation group, the average pain intensity score was 0.4 (0.8). There was a marked difference between the Sedation and TIVA groups with respect to the time from the end of the procedure until the maximum MPADS score was reached: respectively, -6.9 (4.0) versus 25.7 (8.4) minutes (p < 0.001). In the TIVA group, changes in mean arterial pressure and heart rate and signs of respiratory depression were significant (p < 0.05). CONCLUSIONS: Combined administration of remifentanil and propofol for colonoscopy provides sufficient analgesia, satisfactory hemodynamic stability, minor respiratory depression, and rapid recovery, and allows patients to be discharged approximately 15 minutes after the procedure.

[The influence of anesthesia methods on renal function in patients without symptoms of nephropathy]. / Wplyw wybranych metod znieczulenia na czynnosc poszczególnych odcinków nefronu u chorych bez cech jawnej nefropatii.

The aim of this study was to assess the influence of some anaesthesia methods on renal function in patients with no clinical and laboratory symptoms of nephropathy. The activity of various parts of the nephron was evaluated on the basis of the urinary excretion of albumins (marker of renal glomeruli function), beta-2-microglobulins (marker of proximal tubule function) and Tamm-Horsfall protein (marker of distal tubule function). 45 patients were divided into three groups, basing on the kind of anaesthesia: "O"--general, "P"--spinal and "N"--local. The patients who were routinely found to have no signs of nephropathy showed no dysfunction of renal glomeruli and distal or proximal tubule as determined by the urinary excretion of albumins, Tamm-Horsfall protein and beta-2-microglobulins prior to the operation. Different anaesthesia techniques had no effect on the urinary excretion of beta-2-microglobulins. In contrast to local and spinal anaesthesia, general anaesthesia significantly increased the urinary excretion of albumins. General, spinal as well as local anaesthesia significantly decreased the urinary excretion of Tamm-Horsfall protein. The decrease in the excretion of this glycoprotein suggests that all types of anaesthesia techniques may influence the function of the distal part of nephron.