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Biomedical subjects

X Viviand

Publications and source records attributed to X Viviand.

At least 19 recordsLinked to original sources

Local antibiotic prophylaxis in surgery.

The perioperative use of antibiotics is an established and accepted technique for the prevention of postoperative infection. Intravenous administration often is preferred, and intramuscular administration is possible, although it has certain drawbacks. This article examines a variety of other routes of administration for delivering antibiotics locally to the surgical site. These techniques merit further study in prospectively randomized trials.

Antibiotic Prophylaxis

Penetration of ceftriaxone (1 or 2 grams intravenously) into mediastinal and cardiac tissues in humans.

Penetration of ceftriaxone into heart tissues (valves, myocardium, auricles, and pericardium) and mediastinal tissues (fat and sternal bone) was evaluated after two regimens of ceftriaxone administration. Ten patients (group 1) were given 1,000 mg of ceftriaxone intravenously 30 min before anesthesia. Ten other patients (group 2) received the same dose and then a second 1,000-mg dose at the time of initiation of cardiopulmonary bypass. Similar and very satisfactory penetrations of ceftriaxone into tissue were observed for both groups. During opening and closure of the thorax, mean ceftriaxone concentration was in excess of the MIC at which 90% of the potential pathogens were inhibited (> or = 4 micrograms/g) in the thoracic fat, the sternal bone, and the pericardium. No significant differences between the two administration regimens in penetration of ceftriaxone into tissue were observed. During cardiopulmonary bypass, the ceftriaxone concentration was > or = 4 micrograms/g in the myocardium, the endocardium, and the auricle. The regimen of ceftriaxone administration did not significantly influence penetration of the drug into heart tissues. However, for some patients in the two groups and mainly in the sternal bone at the time of thorax closure (6 patients in group 1 and 5 patients in group 2), ceftriaxone levels in tissues were less than the MICs (4 micrograms/g) for some potential pathogens (methicillin-susceptible Staphylococcus aureus and methicillin-susceptible Staphylococcus epidermidis). During the different steps of the surgical procedures, all (10 of 10) patients in each group had tissue ceftriaxone levels greater than the MICs for gram-negative aerobic bacilli (0.1 microgram/g), except for Pseudomonas spp.

Bone and Bones

Concentrations of ceftriaxone (1,000 milligrams intravenously) in abdominal tissues during open prostatectomy.

Ceftriaxone concentrations in abdominal tissues were evaluated at different stages of open prostatectomy. Ceftriaxone was administered as antibiotic prophylaxis, and 15 consecutive patients were given a single dose of ceftriaxone (1,000 mg intravenously in 1 min) 30 min before surgery. Ceftriaxone concentrations in tissue were determined at three stages of the surgical procedure; upon the opening of the abdominal cavity, during the prostatectomy, and upon the closure of the abdominal cavity. Samples of the following tissues or sample were assayed: epiploic and abdominal-wall fat; Retzius' space, bladder, and prostate tissue; and urine. During the different stages of the surgical procedure, for all patients, and in the different tested tissues, ceftriaxone concentrations greater than or equal to the cutoff point (4 micrograms/g of tissue) were measured. The highest concentrations were obtained in the bladder (43 +/- 18 micrograms/g) and in the prostate (35 +/- 18 micrograms/g). In fatty tissues, concentrations were between 13 +/- 5 and 22 +/- 8 micrograms/g. All patients (15 of 15) had ceftriaxone levels in tissue greater than the MICs for the potential pathogens (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis). In conclusion, during open prostatectomy and after the use of a single dose of ceftriaxone (1,000 mg), high antibiotic levels were obtained throughout the surgical procedure in the tissues potentially involved in postoperative infection.

Abdominal Muscles

Selective decontamination of the digestive tract in multiple trauma patients. A prospective double-blind, randomized, placebo-controlled study.

STUDY OBJECTIVE: The aims of the study were to evaluate the technique of selective digestion decontamination (SDD) in preventing the development of nosocomial infections in a selected population and to assess the effects on colonization of the oropharynx, nares, and bronchi. A financial assessment was also performed. DESIGN: Prospective, double-blind, randomized placebo-controlled trial using amphotericin B, colistin sulfate (polymixin E), and gentamicin applied to the nares, the oropharynx, and enterally; no parenteral antibiotics were given during the study period. The SDD was applied every 6 h during the study period. SETTING: Multidisciplinary ICU in a university hospital. PATIENTS: A total of 148 trauma patients admitted emergently and intubated within less than 24 h were enrolled. Seventy-two patients who received placebo and 76 treated patients were analyzed on an "intention-to-treat" basis. INTERVENTIONS: Microbiologic surveillance samples of oropharyngeal and bronchial secretions, urine, and any other potentially infected sites were taken at the time of ICU admission and twice weekly thereafter until discharge from the unit. MEASUREMENTS AND RESULTS: With the use of SDD, colonization was significantly reduced in the oropharynx and nares (<0.05) but not in bronchi. However, episodes of bronchopneumonia were significantly reduced (19 in the active group vs 37 in the placebo group; p,0.01). Staphylococcus aureus remained the main potential pathogen causing bronchial colonization and subsequent bronchopneumonia. There was no reduction in the incidence of other infections. Days in the ICU, duration of mechanical ventilation, and mortality rate were unchanged. After the use of SDD, Gram-positive colonization tended to increase and this was mainly due to methicillin-resistant coagulase-negative staphylococci. The total cost of antibiotic therapy ($62,117 [US] in the placebo group and $36,008 in the SDD group) was decreased by 42% with the use of SDD. Clinically important complications of SDD were not encountered. CONCLUSIONS: The use of SDD in this population of trauma patients reduced the incidence of bronchopneumonia and the total charge for antibiotics. Stay in the ICU, mechanical ventilation, and mortality rate were unchanged. Methicillin-resistant coagulase-negative staphylococci were selected by SDD in some patients and the clinical relevance of this colonization needs further evaluation.

Amphotericin B

Comparison of concentrations of two doses of clavulanic acid (200 and 400 milligrams) administered with amoxicillin (2,000 milligrams) in tissues of patients undergoing colorectal surgery.

The concentrations of clavulanic acid and amoxicillin were determined in sera and different abdominal tissues of 17 patients who underwent elective colorectal surgery. Patients were randomly allocated to two groups. At the time of induction of anesthesia, patients in group 1 were given 200 mg of clavulanic acid with 2,000 mg of amoxicillin and patients in group 2 received 400 mg of clavulanic acid with 2,000 mg of amoxicillin. In both groups, the initial dose was administered again after 2 h. Blood samples were collected to determine peak and trough antibiotic levels. Serial blood samples were also collected at predetermined periods (opening and closure of the abdominal cavity and surgical anastomosis). Abdominal wall fat, epiploic fat, and colonic wall tissue samples were collected simultaneously. Antibiotic concentrations were determined by high-performance liquid chromatography. Increasing the dose of clavulanic acid to 400 mg resulted in significantly higher peak and trough levels in serum (P < 0.03). Following the injection of 400 mg, mean concentrations of clavulanic acid in the fatty tissues were significantly increased at the time of opening (P < 0.02). The concentrations of clavulanic acid and amoxicillin in fatty tissues were 17 to 52% and 12 to 23% of the levels in sera, respectively. In the colonic wall, the concentrations of clavulanic acid and amoxicillin were 52 to 63% and 49 and 27% of the levels in sera, respectively. In sera, clavulanic acid given at a dose of 200 or 400 mg reached or exceeded the concentrations found to be effective in vitro to reduce the MICs of amoxicillin from the resistant to the susceptible category for 90% of the potential pathogens. In most of the tissues investigated, increased the dose of clavulanic acid to 400 mg resulted in a significantly higher number of samples with concentrations found to be effective in vitro (72 versus 11%; P < 0.05). In conclusion, increasing the dose of clavulanic acid to 400 mg resulted in higher levels in sera and improved penetration into the abdominal tissues in patients undergoing colorectal surgery.

Adipose Tissue

Comparing two heat and moisture exchangers with one vaporizing humidifier in patients with minute ventilation greater than 10 L/min.

STUDY OBJECTIVE: To evaluate in patients submitted to minute ventilation > 10 L/min the ability to preserve patients' heat and humidity of two heat and moisture exchangers (HMEs) and one vaporizing humidifier (VH). DESIGN: Prospective, randomized, comparative, non-blinded study. SETTING: Intensive care unit of a university hospital. PATIENTS: Nine tracheally intubated, mechanically ventilated patients, sedated and submitted to mechanical ventilation with minute ventilation > 10 L/min. INTERVENTIONS: Using the psychrometric method, relative humidity (RH) and absolute humidity (AH) of inspired gas were obtained as well as temperature of inspired gas and tracheal temperatures (maximal and minimal). Following a randomized order, each patient was ventilated for two 24-h periods with a vaporizing humidifier (Bennett Cascade 2, Bennett; France) and one of two HMEs: Pall Ultipor filter BB50 (Pall Biomedical; France) or DAR Hygroster filter (Peters; France). Both were first tested for a 45-min period and then the HME that achieved the best performance in terms of temperature and water preservation was tested for 24 h. MEASUREMENTS AND RESULTS: During the 45-min test period, the Pall Ultipor HME achieved a lower performance than the other two systems for any of the studied parameters (p < 0.05 to p < 0.0001). The DAR Hygroster HME achieved lower temperature of inspired gas (29.9 vs 32.0 degrees C, p < 0.005) and lower absolute humidity (29.3 vs 33.2 mg H2O/L, p < 0.005) than the Bennett Cascade 2. After 24 h of use, lower values of temperature of inspired gas (28.5 vs 32.0 degrees C, p < 0.002) and of AH (28.0 vs 33.6 mg H2O/L, p < 0.001) were obtained with the DAR Hygroster HME than with the Bennett Cascade 2. No differences were found between the two systems for the other tested parameters. At that time, no patients had RH lower than 97% and absolute humidity lower than 23 mg H2O/L with the use of the DAR Hygroster HME. CONCLUSIONS: In patients with minute ventilation > 10 L/min, the DAR Hygroster HME showed a thermic and humidification capability similar to the reference system, the Bennett Cascade 2 VH. In these patients, the Pall Ultipor HME had a significantly lower capability.

Adolescent

[Penetration of ceftriaxone (1 or 2 gr intravenous) into mediastinal and cardiac tissues in man].

Ceftriaxone penetration into heart tissues (valves, myocardium, auricles and pericardium) and mediastinal tissues (fat and sternal bone) was evaluated after two regimens of ceftriaxone administration. Ten patients were given 1,000 g intravenously of ceftriaxone 30 min. before anesthesia. Ten other patients received the same dose and then a second 1,000 mg dose at the time of initiation of cardiopulmonary bypass. Similar and very satisfactory ceftriaxone tissue penetrations were observed in both groups. However, for some patients in the two groups and mainly in the sternal bone at the time of thorax closure, ceftriaxone levels in tissues were less than the MICs for some potential pathogens (Methicillin susceptible Staphylococcus aureus and Staphylococcus epidermidis). During the different steps of the surgical procedures all patients in both groups had tissue levels greater than the MICs for Gram negative aerobic bacilli, except for Pseudomonas spp.

Adult

[Modes of administration of Diprivan].

Administration of propofol using standard syringe pumps has become routine in anaesthesia. The marketing of syringe pumps adapter for anaesthesia (high flow rate enabling a bolus injection and a slower rate for maintenance), allows an easier setting up of total intravenous anaesthesia. Computer-aided infusion of propofol will undoubtedly expand in the near future, as a result of the forthcoming marketing of computer-controlled infusion pumps and of improvement in the recognition of accurate individual pharmacokinetic parameters. This computer-aided infusion will be based on a blood concentration criterion, and no longer on a dosage regimen given to the patient. A closed loop regulatory system remains in the domain of research.

Drug Delivery Systems

Penetration of vancomycin into mediastinal and cardiac tissues in humans.

Vancomycin penetration into heart tissues (valves, myocardium, auricles, and pericardium) and mediastinal tissues (fat and sternal bone) was evaluated after two regimens of vancomycin administration. Ten patients were given 15 mg of vancomycin per kg of body weight before anesthesia. Ten other patients received the same dose and then a second 7.5-mg/kg dose at the time of initiation of cardiopulmonary bypass. Similar and satisfactory vancomycin tissue penetrations were observed in both groups. However, for some patients in the two groups, vancomycin levels in tissue were less than the MICs for potential pathogens (Staphylococcus aureus and Staphylococcus epidermidis).

Adipose Tissue

[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

[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

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

[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

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

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

[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