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Biomedical subjects

X Viviand

Publications and source records attributed to X Viviand.

50 records · Page 3Linked to original sources
PubMed1994

[Penetration of vancomycin in cardiac and mediastinal tissues in humans].

Vancomycin penetration into heart tissues (valves, myocardium, auricles and pericardium) and mediastinal tissues (fat and sternal bone) after two regimens of administration was evaluated in a prospective, randomized study. Twenty adult patients undergoing mitral or aortic valve replacement were included in the study and divided into two groups of ten patients each: Group 1 patients were administered a 15 mg/kg intravenous dose of vancomycin over 90 min upon anesthesia. Group 2 patients received the same dose followed by a second 7.5 mg/kg intravenous dose of vancomycin over 30 min at time of initiation of the cardiopulmonary bypass. In both groups further vancomycin administrations (10 mg/kg) were performed on hour 8, 16 and 24. Plasma and tissue vancomycin concentrations were assayed by fluorescence polarization immunoassay. At different times of the surgical procedures (thorax opening and closure, period of cardiopulmonary bypass) 67 to 100% of the patients in group 1 had vancomycin concentrations in the studied tissues above the MIC 90 for Staphylococcus aureus (1 microgram/g) and Staphylococcus epidermidis (2 micrograms/g). In group 2, for the same periods and the same tissues, 72 to 100% of patients had adequate vancomycin concentrations. In group 1 patients, mean ratios of vancomycin tissue concentrations/MIC 90 were 6 +/- 2 to 20 +/- 4 for Staphylococcus aureus (MIC 90: 1 microgram/g) and 3 +/- 1 to 10 +/- 4 for Staphylococcus epidermidis (MIC 90: 2 micrograms/g). In group 2 patients, mean ratios were 8 +/- 3 to 20 +/- 4 for Staphylococcus aureus and 4 +/- 1 to 10 +/- 3 for Staphylococcus epidermidis. The use of a second dose of vancomycin in group 2 significantly increased plasma concentrations (P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Computer-assisted intravenous anesthesia: value, method and use].

Total intravenous anaesthesia (TIVA) is becoming increasingly popular among anaesthetists. It has several advantages, namely each component of the anaesthetic protocol can be independently controlled, and the operating room remains unpolluted with nitrous oxide or volatile anaesthetic agents. TIVA aims to maintain a constant blood concentration of each anaesthetic agent. This means that infusion rates need to be repeatedly altered. A computer calculates theoretical blood concentrations of agent according to a pharmacokinetic model, and drives an infusion device. Only a few programmes have been developed by research teams. No commercial device is available as yet. However, there are several syringe pumps and volumetric pumps which are accurate enough for use in TIVA and which may be controlled by computer. Clinical studies have shown the benefits of TIVA: greater haemodynamic stability, decreased drug consumption, more rapid recovery, and a lesser need for postoperative ventilatory support. The most appropriate agents are propofol and etomidate as hypnotics, alfentanil and sufentanil for opioids, vecuronium and atracurium as muscle relaxants. Etomidate is not recommended for prolonged infusions, because of the risk of adrenocortical suppression. TIVA seems to be attractive for neurosurgery, thoracic surgery, day case surgery, endoscopic procedures, and anaesthesia in remote locations. Unfortunately, it is an expensive technique. Moreover, there is considerable interpatient variability of the drug concentration required for a same clinical effect. Two methods are proposed to decrease this variability: population pharmacokinetic models and Bayesian forecasting. Closed loop systems are still research tools. It is concluded that computer-driven anaesthesia is the equivalent to the vaporizer for volatile agents. However, further clinical studies are needed to determine whether the advantages of this technique outweigh its disadvantages.

Analgesics, Opioid↗
PubMed1993

Sufentanil increases intracranial pressure in patients with head trauma.

BACKGROUND: Sufentanil is an intravenous opioid often used as a component of anesthesia during neurosurgical procedures. However, the effects of sufentanil on intracranial pressure in patients with diminished intracranial compliance are not well established, and remain controversial. METHODS: Ten patients with head trauma, in each of whom the trachea was intubated, were studied for the effects of sufentanil on intracranial pressure (ICP) and on cerebral perfusion pressure (CPP). In all patients, ICP monitoring was instituted before the study. Sedation was obtained using a propofol infusion, and paralysis was achieved with vecuronium. After obtaining control of ICP (between 15 and 25 mmHg) hemodynamic values and blood gas tensions (PaCO2 between 30 and 35 mmHg), the level of sedation was deepened with an intravenous injection of sufentanil (1 microgram/kg over 6 min), followed by an infusion of 0.005 microgram.kg-1min-1. Mean arterial pressure (MAP), ICP (fiberoptic intracranial pressure monitor), and end-tidal CO2 were continuously measured and recorded at 1-min intervals throughout the 30-min study period. RESULTS: Sufentanil injection was associated with a statistically significant increase in ICP of 9 +/- 7 mmHg (+ 53%), which peaked at 5 min. Then ICP gradually decreased and returned to baseline after 15 min. This was accompanied by a significant decrease in MAP (24% decrease) and, thus, CPP (38% decrease). After 5 min, MAP and CPP gradually increased, but remained significantly decreased throughout the study. CONCLUSIONS: The results of the current study indicate that caution should be exercised in the administration of sufentanil bolus to patients with abnormal intracranial elastance, particularly if ICP is significantly increased.

Adolescent↗
PubMed1993

[Tissue diffusion of amoxicillin-clavulanic acid for antibiotic prophylaxis in colorectal surgery].

Tissue penetration of amoxicillin and clavulanic acid given for antibiotic prophylaxis was studied in 15 patients. On induction of anesthesia patients were given 2 g amoxicillin and 200 mg clavulanic acid. The same dose was given two hours later. At time of surgical incision amoxicillin and clavulanate levels were 15.9 +/- 7.7 micrograms/g and 2.23 +/- 2.69 micrograms/g in abdominal wall fat and 16.6 +/- 10.5 and 1.72 +/- 1.35 micrograms/g in epiploic fat, respectively. Similar levels were measured at time of closure of the abdomen. In colonic wall, amoxicillin et clavulanate levels were 22.7 +/- 13.4 micrograms/g and 2.65 +/- 2.35 micrograms/g. By comparison with blood levels, tissue penetration of both drugs was 20 to 30 p. cent into fatty tissues and 60 to 70 p. cent into colonic wall.

Adipose Tissue↗
PubMed1992

Pharmacodynamic properties of propofol during recovery from anaesthesia.

Propofol was used to induce and maintain anaesthesia in 20 healthy adult ASA physical status 1 patients undergoing dental surgery. Recovery was studied using psychometric tests and clinical assessment while propofol blood levels were obtained at the same study times. Recovery was rapid and there were no significant differences 60 min after anaesthesia (t60) for the tracing test and 90 min for the choice reaction time. All patients were orientated in time at t30 and in space at t45; Stewart's score was maximal in all patients at t60; recovery of normal walking was slower, i.e. t120. Return to baseline for psychometric function was linked to a decrease in propofol blood level, for both the tracing test (P less than 10(-6)) and the choice reaction time (P less than 10(-3)). We conclude that propofol is a suitable anaesthetic agent for induction and maintenance of short duration dental anaesthesia.

Adult↗
PubMed1991

Simplification of the SAPS by selecting independent variables.

A series of 950 consecutive admissions to a multidisciplinary ICU were divided into 2 groups (group I = 450 and group II = 500). In the first group, 351 admissions were used to retrospectively create two scores: SAPS.R derived from the 14 original SAPS variables and SAPS.E derived from 22 variables (14 of SAPS plus 8 additional biological variables). Using a multiple logistic regression analysis only 5 variables were retained for SAPS.R and 7 for SAPS.E. In the second group, 446 patients were used to assess prospectively the discriminating power of SAPS, SAPS.R, SAPS.E by comparing the areas under the receiver operating characteristic (ROC) curves. There were no significant differences between the overall accuracies of these 3 scores. Adding biological variables did not improve the accuracy but the number of variables in the original SAPS could be greatly reduced.

Adolescent↗
PubMed1991

[Effects of an additional dose of propofol on intraocular pressure in patients over 60 years of age].

Changes in intraocular pressure (IOP) and mean arterial pressure (MAP) were studied in fifty patients, ASA 1 or 2, aged more than 60 years and scheduled for surgery of the anterior chamber of the eye. The exclusion criteria were: arterial hypertension, raised IOP, obesity, renal or hepatic disease, treatment likely to alter IOP, and a possibly difficult intubation. The patients were randomly assigned to groups P1 (n = 25) and P2 (n = 25). All were given lorazepam 1 mg orally 90 min before induction, which was carried out with propofol 1.5 mg.kg-1 and vecuronium 0.1 mg.kg-1. Patients in group P1 were intubated as soon as the train-of-four response (TOF) had been abolished. Those in group P2 were given an additional 0.7 mg.kg-1 dose of propofol before intubation. MAP, heart rate and IOP were measured before and after induction, and 1, 2 and 3 min after intubation. IOP decreased after induction, and remained below the baseline values at all times in both groups. MAP had a similar course in both groups up to 1 min after intubation: a decrease after induction followed by an increase after intubation. In group P1, MAP remained above control values 2 and 3 min after intubation, whereas in P2 it remained below. From this study, it can be concluded that using an additional dose of propofol in elderly patients was not useful for avoiding the rise in IOP due to endotracheal intubation. This was all the more so as the haemodynamic effects of such a dose of propofol could have deleterious effects in these patients.

Age Factors↗
PubMed1990

[How to assess the psychomotor test "Track Tracer"?].

The psychomotor test "Track Tracer" is usually assessed by measuring the number of errors and the time needed for its completion. The link existing between the number of errors and the time of completion permitted the authors to propose a scoring system representing a reliable evaluation of psychomotor function recovery.

Anesthesia Recovery Period↗
PubMed1989

Comparison of four severity scores in patients with head trauma.

This study examines the performance of four severity scores in a group of 70 consecutive patients with head trauma, hospitalized in the same neurosurgical ICU. On day of admission to the ICU, data were collected from each patient to compute Acute Physiology Score (APS), Simplified Acute Physiology Score (SAPS), Glasgow Coma Scale (GCS), and Therapeutic Intervention Scoring System (TISS). These four scores were statistically correlated with the outcome of patients. Results also indicate that GCS was superior to any other score in predicting outcome of patients and allowed better specificity and sensitivity. Regarding the level of care needed by patients, TISS was superior to any other scoring system. The difficulty in estimating individual prognosis is discussed, since scoring systems are aimed at classifying groups of patients, not individuals. It is concluded that GCS is a simpler and less time consuming method in predicting outcome of patients with head trauma.

Adolescent↗