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Biomedical subjects

I Murat

Publications and source records attributed to I Murat.

At least 55 records · Page 3Linked to original sources
PubMed1998

Heart rate control of blood pressure variability in children: a study in subjects with fixed ventricular pacemaker rhythm.

1. To investigate the influence of heart rate variability on blood pressure variability, short-term variability in heart rate and blood pressure was studied in 10 children with fixed ventricular pacemaker rhythm (80 beats/min). Ten healthy children, in sinus rhythm, served as a reference population. 2. Arterial blood pressure and heart rate were measured continuously using a finger arterial device and an ECG respectively. Power spectra for heart rate and blood pressure (systolic and diastolic) were calculated in both supine and orthostatic positions. In addition, acute changes in blood pressure and heart rate during active standing were studied. 3. Healthy children exhibited considerable heart rate variability, which was slightly more pronounced in the supine position, while children with a fixed ventricular rate had no heart rate variability in either position. 4. Despite the differences in heart rate variability, mean systolic blood pressure and its variability profiles were poorly affected by the suppression of heart rate variability. The lack of autonomic control on the sinus node was associated with a reduction in magnitude of the changes in systolic blood pressure variability induced by orthostatic posture. 5. The suppression of heart rate fluctuations induced a noticeable decrease in diastolic blood pressure fluctuations, which was most conspicuous in the children with fixed cardiac rhythm when in the supine position. This may be explained by the lack of diastolic blood pressure fluctuations, physiologically due to heart rate fluctuations through the run-off effect: the longer the cardiac cycle, the greater the diastolic pressure decay. These results may challenge the classical theory of baroreflex-mediated diastolic blood pressure control described in adult patients. 6. During active standing, the early drop in systolic blood pressure was greater in subjects with fixed ventricular rhythm. A rise in heart rate of 36 beats/min was observed in the healthy subjects in response to active standing. 7. We conclude that in normal children, heart rate fluctuations increase the blood pressure variability rather than buffering it. However, during acute orthostatic stress, the abrupt baroreflex-mediated heart rate rise may partly compensate for the reduction in blood pressure.

Adolescent↗
PubMed1998

[Intravenous iron in the treatment of postoperative anemia in surgery of the spine in infants and adolescents].

PURPOSE OF THE STUDY: Spinal fusion surgery often leeds to massive bleeding responsible for anemia in the postoperative period. The aim of this study was to compare the effect of IV iron III hydroxide sucrose complex (Venofer) versus oral iron fumarate administration in postoperative anemia. The efficacy of both treatments was evaluated by comparing hemoglobin level in the postoperative period. METHODS: Two groups of sixteen patients, scheduled for anterior and/or posterior spinal fusion, were compared. Group 1, historical, was treated by supplementation of 10 mg/kg/day oral iron fumarate. Administration was started when hemoglobin level fell below 9 g/100 ml. Group 2 was treated by intravenous iron sucrose complex using same criteria as in group 1 for starting administration. The dosage of iron was individually adapted according to a target hemoglobin level of 13 g/100 ml and to the actual lowest hemoglobin level measured. The total iron deficit was calculated with the following formula: total iron deficit (mg) = 0.24 x body weight (kg) x (target Hb-actual Hb)(g/l). The patients were supplemented by 3 mg/kg/day until the calculated iron deficit was compensated. RESULTS: Both groups were identical regarding age and lowest hemoglobin level reached in the postoperative period. Hemoglobin increased by 0.25 g/day in group 1, and by 0.36 g/day in group 2. In others words, the beneficial effect of IV iron versus oral iron administration was as high as 45 per cent (p = 0.003). CONCLUSION: Intravenous iron therapy as ferric sucrose complex is a new and more effective form of iron therapy than oral iron therapy to restore postoperative hemoglobin after spinal surgery in children.

Administration, Oral↗
PubMed1997

[A low dose of nalbuphine reverses respiratory depression but not analgesia induced by intraspinal morphine].

Postoperative pain management after scoliosis surgery is based in our institution on intrathecal morphine administration. This case report describes an immediate and major postoperative respiratory depression that occurred in the recovery room, requiring the maintenance of the endotracheal tube. This respiratory depression was reversed by i.v. administration of a low dose of nalbuphine, which allowed tracheal extubation without suppression of morphine-induced analgesia.

Adolescent↗
PubMed1997

Video-assisted thoracoscopic surgery for right middle lobectomy in children.

This case-control study was designed to evaluate the potential advantages and disadvantages of video-assisted thoracoscopic surgery for right middle lobectomy in children. Ten children (6.1 +/- 3.0 yr, mean +/- SD) who underwent right middle lobectomy under videoscopy were compared with 10 controls matched for age (6.8 +/- 3.5 yr) and operated by thoracotomy (muscle-sparing technique) during the same period by the same surgeon. Operating time was significantly longer in the videoscopy group than in the thoracotomy group (146 +/- 28 mn vs 100 +/- 27 mn, P < 0.001). Minimum oxygen saturation values were significantly higher in the videoscopy group whereas oxygen requirements did not differ between groups. Incidence of postoperative respiratory complications (mainly atelectasis) was similar in the two groups. No difference in postoperative analgesic requirements in the postoperative period was demonstrated. No real benefit or disadvantage of videoscopy over standard thoracotomy could be observed in this retrospective case-control study.

Anesthesia, General↗
PubMed1996

Pharmacokinetics of propofol after a single dose in children aged 1-3 years with minor burns. Comparison of three data analysis approaches.

BACKGROUND: No complete pharmacokinetic profile of propofol is yet available in children younger than 3 yr, whereas clinical studies have demonstrated that both induction and maintenance doses of propofol are increased with respect to body weight in this age group compared to older children and adults. This study was therefore undertaken to determine the pharmacokinetics of propofol after administration of a single dose in aged children 1-3 yr requiring anesthesia for dressing change. METHODS: This study was performed in 12 children admitted to the burn unit and in whom burn surface area was less than or equal to 12% of total body surface area. Exclusion criteria were: unstable hemodynamic condition, inappropriate fluid loading, associated pulmonary injury, or burn injury older than 2 days. Propofol (4 mg.kg(-1))plus fentanyl (2.5 microg.kg(-1)) was administered while the children were bathed and the burn area cleaned during which the children breathed spontaneously a mixture of oxygen and nitrous oxide (50:50). Venous blood samples of 300 microl were obtained at 5, 15, 30, 60, 90, and 120 min, and 3, 4, 8, and 12 thereafter injection; an earlier sample was obtained from 8 of 12 children. The blood concentration curves obtained for individual children were analyzed by three different methods: noncompartmental analysis, mixed effects population model, and standard two-stage analysis. RESULTS: Using noncompartmental analysis, total clearance of propofol (+/-SD) was 0.053+/-0.013l.kg(-1).min(-1), volume of distribution at steady state9.5 +/- 3.7l.kg(-1),and residence time 188 +/- 85 min. Propofol pharmacokinetics were best described by a weight-proportional three-compartmental model in both population and two-stage analysis. Estimated and derived pharmacokinetic parameters were similar using these two pharmacokinetic approaches. Results of population versus two-stage analysis are as follow: systemic clearance 0.049 versus 0.048 l.kg(-).min(-1), volume of central compartment 1.03 versus 0.95 l.kg(-1), volume of steady state 8.09 versus 8.17 l.kg(-1). CONCLUSIONS: The volume of the central compartment and the systemic clearance were both greater than all values reported in older children and adults. This is consistent with the increased propofol requirements for both induction and maintenance of anesthesia in children 1-3 yr. (Key words: Anesthesia: pediatric. Pharmacokinetics: propofol.)

Age Factors↗
PubMed1995

[Sevoflurane].

Sevoflurane, a methylethylether halogenated solely with fluorine, is characterized by a low blood/gas solubility (blood/gas partition coefficient = 0.65). This feature allows in a more rapid uptake and elimination than with more soluble agents. MAC is about 2 vol% in young adults and 2.5 vol% in children of more than 6 months of age. It undergoes degradation by soda lime in various components. Among them, compound A (an olefin) produces renal toxicity in rats. Total sevoflurane metabolism represents about 5% of inhaled dose and produces inorganic fluorides. However no renal toxic effects has been reported up to now in animals and in patients. The effects on central nervous and cardiovascular systems are close to those of isoflurane. It decreases cerebral vascular resistances and cerebral oxygen consumption, but does not cause convulsive activity. It decreases myocardial contractility, systolic arterial pressure and systemic vascular resistances, but heart rate remains basically unchanged up to 1 MAC. It does not sensitize the myocardium to catecholamines. It depresses ventilation in a dose-dependent fashion, this effect being more pronounced than that of halothane but less than that of both isoflurane and enflurane. It is not irritant for the airways and has some bronchodilatory effect. In adults, recovery is more rapid than with isoflurane. In children, sevoflurane seems a promising agent owing to its good acceptance for mask induction, as well as its favourable haemodynamic profile. However due to its rapid elimination, analgesic drugs should be administered early enough to decrease the incidence of postoperative pain.

Adolescent↗
PubMed1995

[Lumbar and sacral epidural anesthesia in children].

This article will briefly review the techniques of epidural anaesthesia via lumbar and sacral routes, as well as the indications and contraindications of the techniques. Guidelines for per- and postoperative use of epidural anaesthesia are provided.

Age Factors↗
PubMed1995

[Latex hypersensitivity: a foreseeable accident?].

This paper describes another case of severe anaphylactic reaction due to allergy to natural rubber during anaesthesia in a child without known risk factors. The day after surgery the child reported that he experienced a few months ago an impressive skin reaction of both face and lips after inflating a latex balloon. It is suggested to try to detect latex allergy during the preoperative visit in all patients by including questions about latex sensitivity such as previous skin reactions or respiratory symptoms after wearing latex gloves or after inflating toy balloons. Patients in whom latex sensitivity is suspected should be tested appropriately in order to perform the planned surgery in a latex-free environment.

Adolescent↗
PubMed1994

[Diprivan in children under 3 years of age].

Today, the lack of the marketing licence for administration of propofol for anaesthesia in children of less than three years does not allow to recommend the administration of propofol for that indication. Its use for sedation in children under fifteen is contra-indicated.

Age Factors↗
PubMed1994

Stereoselective disposition of ibuprofen enantiomers in infants.

The pharmacokinetics of the enantiomers of ibuprofen were investigated after oral administration of a single 7.6 +/- 0.3 mg kg-1 dose of the racemate in 11 infants. Mean (+/- s.d.) half-lives were 1.6 +/- 0.5 h for S(+) and 1.5 +/- 0.5 h for R(-) and mean (+/- s.d.) AUC values were 31.5 +/- 14.3 mg l-1 h for S(+) and 36.6 +/- 13.8 mg l-1 h for R(-). Since plasma concentrations of the active S(+)-isomer were lower than those reported in adults, a higher dosage might be required in infants.

Administration, Oral↗
PubMed1994

Induction and recovery characteristics and hemodynamic responses to sevoflurane and halothane in children.

The present study was designed to compare induction and recovery characteristics of sevoflurane and halothane anesthesia in children, and to assess the hemodynamic profile of both anesthetics during induction and maintenance of anesthesia. Thirty-four children (aged 9 mo-9 yr) scheduled for ambulatory surgery were allocated randomly to groups to receive either halothane (HALO, n = 17) or sevoflurane (SEVO, n = 17) in a mixture of O2 and N2O (40:60) for mask induction and maintenance of anesthesia. The inspired concentrations used for inhalation via a mask were increased every five breaths and were successively 1%, 2%, 3%, and 3.5% for HALO and 2%, 4%, 6%, and 7% for SEVO. After tracheal intubation, expired concentration was maintained at 1 minimum alveolar anesthetic concentration (MAC) corrected for age until skin closure. Analgesia was provided by epidural anesthesia using a mixture of plain 1% lidocaine and 0.25% bupivacaine. Induction and recovery characteristics as well as hemodynamic data were recorded. The two groups were identical in age, weight, and duration of anesthesia and surgery. Time to intubation was the same between groups. In the SEVO group, five children exhibited mild excitement, while in the HALO group, one mild laryngospasm and one transient cardiovascular deterioration were observed. In the SEVO group, a significant increase in heart rate (HR) was observed before tracheal intubation, but during maintenance of anesthesia HR and systolic arterial pressure (SAP) did not change compared to control values. In the HALO group, HR did not change throughout the study, whereas SAP remained significantly below control values throughout both induction and maintenance of anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗