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Biomedical subjects

K Nieminen

Publications and source records attributed to K Nieminen.

At least 19 recordsLinked to original sources
PubMed2002

Sevoflurane anaesthesia in children after induction of anaesthesia with midazolam and thiopental does not cause epileptiform EEG.

BACKGROUND: Sevoflurane is a methyl ether anaesthetic commonly used for induction and maintenance of general anaesthesia in children. Sevoflurane is a non-irritant and acts quickly so induction is usually calm. However, inhalation induction with high concentrations of sevoflurane can cause convulsion-like movements and seizure-like changes in the electroencephalogram (EEG). Little is known about the EEG during maintenance of anaesthesia with sevoflurane, so we planned a prospective trial of sevoflurane maintenance after i.v. induction with benzodiazepine and barbiturate, which is another common induction technique in children. METHODS: EEG recordings were made before premedication with midazolam (0.1 mg kg(-1) i.v.), during induction of anaesthesia with thiopental (5 mg kg(-1)), and during maintenance with sevoflurane (2% end-tidal concentration in air/oxygen without nitrous oxide) in 30 generally healthy, 3- to 8-year-old children having adenoids removed. Noise-free EEG data of good quality were successfully recorded from all 30 children. RESULTS: Two independent neurophysiologists did not detect epileptiform discharges in any of the recordings. CONCLUSION: Premedication with midazolam, i.v. induction with thiopental and maintenance of anaesthesia with 2% sevoflurane in air does not cause epileptiform EEG patterns in children.

Anesthesia, General↗
PubMed2001

Modelling aerosol processes related to the atmospheric dispersion of sarin.

We have developed mathematical models for evaluating the atmospheric dispersion of selected chemical warfare agents (CWA), including the evaporation and settling of contaminant liquid droplets. The models and numerical results presented may be utilised for designing protection and control measures against the conceivable use of CWA's. The model AERCLOUD (AERosol CLOUD) was extended to treat two nerve agents, sarin and VX, and the mustard agent. This model evaluates the thermodynamical evolution of a five-component aerosol mixture, consisting of two-component droplets together with the surrounding three-component gas. We have performed numerical computations with this model on the evaporation and settling of airborne sarin droplets in characteristic dispersal and atmospheric conditions. In particular, we have evaluated the maximum radii (r(M)) of a totally evaporating droplet, in terms of the ambient temperature and contaminant vapour concentration. The radii r(M) range from approximately 15-80 microm for sarin droplets for the selected ambient conditions and initial heights. We have also evaluated deposition fractions in terms of the initial droplet size.

Aerosols↗
PubMed2001

Sacrospinous ligament fixation for massive genital prolapse in women aged over 80 years.

OBJECTIVE: To assess the feasibility of vaginal sacrospinous ligament fixation for women over 80 years of age with massive vaginal vault or uterovaginal prolapse. DESIGN: Retrospective observational study with long term follow up. SETTING: Department of Obstetrics and Gynaecology, Tampere University Hospital, Finland. SAMPLE: and Methods The study group consisted of 25 women with a mean (SD) [range] age of 83 (3) [80-93] years: 13 had posthysterectomy vaginal vault prolapse and 12 had massive uterovaginal prolapse. All underwent vaginal sacrospinous ligament fixation with repair of pelvic floor relaxation. Women with uterovaginal prolapse also underwent concomitant vaginal hysterectomy. The long term outcome was assessed in 19 women. The mean follow up period was 33 (31) [2-113] months. MAIN OUTCOME MEASURES: Intra- and post-operative morbidity, mortality and recurrence of prolapse. RESULTS: Sixteen of the 25 women (64 %) had no major intra- or post-operative complications. The mean estimated blood loss was 400 (280) mL, and seven women received blood transfusions. Four women (16%) had cardiovascular complications, and one died of pulmonary embolism. All four had a history of vascular disease. One woman had symptomatic recurrence of vault prolapse treated with a vaginal pessary; two women had asymptomatic cystocele and one had an enterocele requiring no treatment. The outcomes were similar for women with or without concurrent vaginal hysterectomy. CONCLUSION: Transvaginal sacrospinous ligament fixation is an effective treatment for massive vaginal vault or uterovaginal prolapse in aged women. Increased blood loss may elevate the risk of cardiovascular complications especially in elderly patients with a history of vascular disease, thus indicating the importance of intraoperative bleeding control.

Aged↗
PubMed2000

IBIS data library: clinical description of the Finnish database. Improved Monitoring for Brain Dysfunction during Intensive Care and Surgery.

Improved monitoring of brain function in intensive care and surgery is a project aiming to develop methods of biosignal processing and interpretation, in order to characterise critical events during anaesthesia and cardiac surgery, effect of anaesthesia regimen, neurophysiological findings of different sedation levels, arousal from post-anaesthesia sedation, post-cardiopulmonary bypass brain dysfunction and early brain dysfunction in patients with multiple organ failure. A data library was collected in the three participating hospitals. This is a description of the data library from the University Hospital of Kuopio, Finland, which includes data from 40 patients after cardiac surgery and from seven patients with multiple organ dysfunction. This project demonstrates that active neuromonitoring can be performed in the intensive care unit without interference with the normal treatment and care. The presented database may serve other scientific workers as a reference for a typical spectrum of perioperative data with respect to severity of disease, length of cardiopulmonary bypass, postoperative levels of sedation and length of hospital stay in cardiac surgery patients, and for types of diseases and outcome in patients with multiple organ dysfunction.

Adult↗
PubMed2000

Single sweep analysis of event related auditory potentials for the monitoring of sedation in cardiac surgery patients.

Event-related potentials (ERPs) from the auditory system were investigated in 28 post-operative cardiac patients in order to assess their relevance in the monitoring of patient sedation level. Midazolam (17 patients) and propofol (11 patients) were the sedative agents used. The auditory ERP components of N100 (HAB100) and mismatch negativity (MMN) were considered. A single sweep method based on the AutoRegressive with eXogenous input (ARX) model, which is able to enhance the evoked responses to each single stimulus, was used to process each sweep and to compute traditional parameters on a sweep-by-sweep basis. Differences in the measured parameters were related to variations in the patient sedation levels classified through Ramsay score. Significant differences (P<0.05) in both MMN and HAB100 parameters were found between light sedation (LS) and deep sedation (DS) levels.

Aged↗
PubMed2000

Repetitive synchronized cyclical oscillations of multisystem parameters subsequent to high-dose thiopental therapy for status epilepticus secondary to herpes encephalitis.

We report a case of status epilepticus secondary to herpes encephalitis, treated with thiopental infusion and mechanical ventilation. The computerized storage and analysis of physiological data led to the detection of repetitive synchronized cyclical oscillations of arterial pressure, heart rate, EEG parameters, peripheral temperature and core temperature. Arterial pressure oscillations have been described in patients who are severely systemically unwell; cardiovascular and brain electrical activity may also oscillate in the presence of raised intracranial pressure. In contrast, this patient had no features of severe systemic illness or of raised intracranial pressure. Our hypothesis is that high-dose thiopental may have been a cause of our findings by producing autonomic dysfunction.

Adolescent↗
PubMed1999

The effect of toremifene on bone and uterine histology and on bone resorption in ovariectomised rats.

The effect of the selective oestrogen receptor modulator, toremifene, to inhibit ovariectomy-induced bone loss was studied in rats. The oral doses were 0.3, 3.0 or 30 mg/kg/day for 2 months. 17beta-oestradiol (5 microg/kg/day, subcutaneously) was used as positive control. One group was also treated with a combination of 17beta-oestradiol (5 microg/kg) and toremifene (3.0 mg/kg). Biochemical markers were urinary hydroxyproline and calcium (adjusted with urinary creatinine levels) and the serum level of pyridinoline cross-linked carboxy terminal telopeptide, a bone specific collagen breakdown product. The femoral and sternal trabecular bone thickness served as histological parameters. Ovarectomy increased the levels of hydroxyproline and pyrodinoline and decreased the trabecular bone thickness compared to the sham-operated control group. This was inhibited by both test compounds but 17beta-oestradiol was more efficient. Toremifene did not reverse the ovariectomy-induced reduction of urinary calcium but inhibited the 17beta-oestradiol-related increase. When administered together with oestradiol, toremifene did not reverse the positive effect of 17beta-oestradiol on bone, however toremifene reversed the oestradiol-related uterothrophic effects. These findings indicate that the antagonistic features of toremifene dominate in the rat uterus the agonistic properties do in the bone.

Amino Acids↗
PubMed1997

Effective obstetric paracervical block with reduced dose of bupivacaine. A prospective randomized double-blind study comparing 25 mg (0.25%) and 12.5 mg (0.125%) of bupivacaine.

BACKGROUND: To study whether paracervical block (PCB) with 12.5 mg (0.125%) of bupivacaine is as effective as with 25 mg (0.25%) and if there are differences in fetal heart rate (FHR) patterns between the doses. METHODS: A prospective, randomized double-blind study. Fifty-two patients received PCB with 25 mg and 45 patients with 12.5 mg of bupivacaine. Pain intensity was assessed by the patients on a horizontal visual analog scale (VAS). Fetal heart rates of the fetuses were analyzed visually concerning basal rate, variability, accelerations, bradycardia, silent pattern and decelerations. RESULTS: The pain relief was statistically significant in both groups up to 120 min after PCB. The VAS-values were similar in both groups both before and after PCB. Fetal heart rate changes appeared in both groups more frequently after than prior to PCB. In patients receiving 25 mg of bupivacaine there appeared to be more FHR changes than in those receiving 12.5 mg. CONCLUSIONS: Paracervical block with 12.5 mg of bupivacaine is an effective method to relieve pain during labor. Fetal heart rate changes seemed to appear less frequently with this reduced dose. It seems that by lowering the dose of bupivacaine it is possible to reduce fetal side-effects without losing analgesic effect.

Adolescent↗
PubMed1989

Serum levels and urinary excretion of mequitazine after a single oral dose.

Pharmacokinetics of mequitazine, a recently introduced peripheral H1-histamine receptor antagonist of phenothiazine type, was followed up to 72 h after the single oral dose of 5 mg of the drug to eight fasted healthy volunteers. Each subject was treated thrice with a dosing interval of 15 days or more. Thus all the results were triplicated. Serum mequitazine was measured by mass fragmentography using a gas-liquid chromatograph/mass spectrometer set in the electron impact mode. Urine phenothiazines were determined fluorometrically before and after cleaving phenothiazines from their glucuronide conjugates. Peak concentration of mequitazine in serum was 3.19 +/- 1.70 (s.d.) ng.ml-1, time to peak concentration 5.67 +/- 1.68 h, elimination half-life 45 +/- 26 h, and elimination rate constant 0.018 +/- 0.007 h-1. Only 10.9 +/- 3.3% of the dose appeared in urine in unconjugated plus the glucuronidated form during the first 72 h. About 46% of the urinary phenothiazines were glucuronide conjugates. The results suggested that after the oral administration only low mequitazine concentrations appeared in serum, most of the drug seemed to be deactivated by the extrarenal route, and the kinetic properties of the drug resembled those of several phenothiazines used for psychiatric therapy.

Administration, Oral↗
PubMed1988

Electrical properties of cultured dorsal root ganglion neurons from normal and trisomy 21 human fetal tissue.

Dorsal root ganglion (DRG) neurons, in 22 degrees C tissue culture containing nerve growth factor, taken from normal and trisomy 21 human fetal tissues, were subjected to current and voltage clamp measurements using a tight-seal whole-cell recording technique. Measurements were made between 1 and 2 weeks in culture, when the electrical properties of both neuron groups were shown to be constant and when mean values for passive electrical parameters did not differ significantly between groups. The duration of the action potential was significantly less in trisomic than in control neurons, and both depolarization and repolarization were accelerated. Tetraethylammonium (5 mM), which partially blocked outward currents, prolonged the rate of repolarization of the action potential in both neuron groups, and abolished the difference in the rate between the groups. Furthermore, the activation rate constants of two model-defined outward potassium currents were significantly higher in trisomic than in control neurons, suggesting that acceleration of repolarization of the action potential in trisomic neurons was due to shorter activation time-constants of outward potassium currents.

Action Potentials↗