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Biomedical subjects

D Benhamou

Publications and source records attributed to D Benhamou.

At least 217 records · Page 12Linked to original sources
PubMed1988

Chemical stability of bupivacaine in pH-adjusted solutions.

Recent clinical studies have suggested that alkalinization of bupivacaine may shorten the time to onset and lengthen its duration of action. However, addition of sodium bicarbonate to commercially manufactured bupivacaine can rapidly produce precipitation. This study was performed to study the stability and precipitation of bupivacaine solutions 0.25% and 0.50% with and without epinephrine 1:200,000 after alkalinization. The results indicate that alkalinization does not increase precipitation above recommended limits and that the concentration of bupivacaine in solutions is maintained at least 6 h after alkalinization.

Bupivacaine↗
PubMed1988

Chemical stability of lignocaine (lidocaine) and adrenalin (epinephrine) in pH-adjusted parenteral solutions.

Recent clinical studies have shown that alkalinizing lignocaine (lidocaine) solutions is an effective way of shortening the time of onset and increasing the duration of anaesthesia. However, alkalinizing lignocaine solutions raises the problem of the stability of these preparations. Moreover, the adrenalin usually associated with it is unstable in alkalinized solutions designed for peridural injection. This study was performed to define the range of pH over which lignocaine and adrenalin in commercial solution is stable. The results indicate that it is possible to alkalinize lignocaine solutions and that the solutions prepared are stable for at least 6 h.

Drug Combinations↗
PubMed1988

Effect of naloxone infusion on analgesia and respiratory depression after epidural fentanyl.

The efficacy of two dosage regimens of intravenous naloxone were compared to avoid nonrespiratory side effects and respiratory depression and yet to preserve analgesia (maximum tolerance to periostial pressure over the tibia) after administration of 200 micrograms epidural fentanyl. Three groups of eight patients were studied: group 1 patients received a loading dose of 0.4 mg IV naloxone followed by naloxone infusion at a rate of 10 micrograms.kg-1.hr-1. Group II patients received a loading dose of 0.2 micrograms naloxone followed by a naloxone infusion at a rate of 5 micrograms.kg-1.hr-1. Group III patients received a saline infusion at a rate of 20 ml/hr. Epidural fentanyl significantly increased tolerance to periostial pain in all three groups (respectively, +38 +/- 20%, +36 +/- 16%, and +35 +/- 14%) (mean +/- SD; P less than 0.05). The naloxone infusion significantly reduced this effect in groups I and II, respectively, -40 +/- 20% and -37 +/- 28% below prenaloxone levels) (P less than 0.05). Nonrespiratory side effects were also reversed in groups I and II. In group III, neither periostial analgesia nor nonrespiratory side effects were affected. The baseline slopes of VE/PETCO2 were 2.34 +/- 1.01, 2.14 +/- 0.66, and 2.68 +/- 1.14 L.min-1.mm Hg-1, respectively, in groups I, II, and III. Epidural fentanyl significantly decreased the slope below baseline levels in each group: -21 +/- 16%, -22 +/- 17%, and -19 +/- 32%, respectively, in groups I, II and III.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Bronchial resection-anastomosis for cicatricial stenosis. Physiopathologic and therapeutic considerations].

The exploration of a stenosis of an intermediate bronchus in a 50 year-old woman showed it to be severe, limited, and non-malignant. Pre-operative angiography showed hypovascularization of the right lower and middle pulmonary lobes. A short resection of the stenosis, with termino-terminal bronchial anastomosis was performed. Post-operative evaluation showed normal bronchography and angiography. This suggests that bronchial stenosis plays a role in the hypovascularization observed before its surgical correction, the most likely hypothesis being vasoconstriction.

Anastomosis, Surgical↗
PubMed1987

Serum hyaluronate in malignant pleural mesothelioma.

The diagnostic value of hyaluronate concentration in effusions of malignant mesothelioma has been extensively reported but no information is available about serum hyaluronate in patients with this cancer. Using a new enzymoimmunologic assay based on hyaluronate-hyaluronectin interaction, serum levels of hyaluronate were measured in 16 patients with malignant pleural mesothelioma, 50 patients with other pleural effusions, and 94 healthy blood donors. The mean serum hyaluronate level in patients with mesothelioma (mean, 750 micrograms/l; range, 29 to 5833 micrograms/l) was significantly higher than in patients with other pleural effusions (mean, 56 micrograms/l; range, 4 to 137 micrograms/l) and than in blood donors (mean, 24 micrograms/l; range, 0 to 94 micrograms/l). Comparison of serum hyaluronate values observed in mesotheliomas with the clinical course of the disease suggests that serum hyaluronate might increase only at an advanced stage of the cancer. Therefore, serum hyaluronate determination has probably no clinical value for early detection of malignant mesothelioma, but might be useful to evaluate the clinical course of this malignancy.

Adult↗
PubMed1987

High frequency jet ventilation: the influence of different methods of injection on respiratory parameters.

Fourteen critically ill patients with ventilatory failure were ventilated with HFJV using a constant driving pressure of 3 atm and a constant I:E ratio of 0.43. In six (group I) HFJV, using a frequency of 100 b.p.m., was delivered via a proximal injector cannula. Four injector cannulae (i.d. 1.8, 1.6, 1.4 and 1.2 mm, respectively) were used at random. In eight patients (group II), HFJV using three frequencies (100, 300 and 600 b.p.m.) was administered either via a 1.8-mm i.d. proximal injector cannula (proximal injection), for via a Hi-Lo jet tracheal tube (distal injection). The following indices were measured in vivo: mean airway pressure (Paw), mean pulmonary volume above apnoeic FRC (delta V), mean alveolar pressure (clamps method) and arterial blood-gas tensions. Injected volume (Vinj), entrainment (E) and tidal volume (VT) were measured in vitro using a water-sealed spirometer. Operating pressure (the pressure in the connecting tube) was measured directly using a high pressure calibrated transducer. In group I, Paw, delta V, PaO2, Vinj and VT significantly decreased whereas operating pressure and E significantly increased when the internal diameter of the injector cannula was reduced. In group II, Paw, delta V, E, VT and operating pressure significantly decreased, whereas Vinj increased and PaO2 and PaCO2 remained unchanged, when proximal injection was switched to distal injection. In both groups, a significant relationship was found between operating pressure and E. At a constant driving pressure, operating pressure increased with narrow injector cannulae and increased frequency, and decreased when proximal injection was switched for distal injection.

Adolescent↗
PubMed1986

High frequency jet ventilation in acute respiratory failure: which ventilator settings?

Seven hypoxaemic patients with acute respiratory failure were ventilated with HFJV (Ventilator VS 600). Arterial oxygenation was improved in each patient by the increases induced in mean airway pressure (PAW) (to 20 cm H2O) using three different ventilatory settings applied in a random order: technique A: I:E ratio 0.43, driving pressure 2.9 bar, no PEEP; technique B: I:E ratio 1.0, driving pressure 1.9 bar, no PEEP; technique C: I:E ratio 0.43, driving pressure 1.8 bar, PEEP 11 cm H2O. Respiratory frequency was maintained at 250 b.p.m. throughout the study. There were no significant differences in PaO2 (FlO2 = 1) or Qs/Qt between the three techniques. In contrast, carbon dioxide elimination was markedly affected by the method used to increase PAW:PaCO2 was significantly higher during technique C (8.5 +/- 3.6 kPa) and technique B (6.6 +/- 2.1 kPa) than during technique A (4.8 +/- 0.9 kPa). Significant increases in cardiac index, heartrate, mean pulmonary arterial pressure and a decrease in the arterio-venous oxygen content difference were observed when PaCO2 increased. We conclude that, to obtain the PAW necessary to improve pulmonary oxygen exchange, more effective carbon dioxide elimination is achieved by increasing the driving pressure, rather than by increasing the I:E ratio, or using a PEEP valve.

Acute Disease↗
PubMed1986

[Malaria].

Explore the source record for details and available documents.

Humans↗
PubMed1985

Factors influencing pulmonary volumes and CO2 elimination during high-frequency jet ventilation.

An external spirometric method using a differential linear transformer was used to measure tidal volume (VT) and to determine factors influencing CO2 elimination and HFJV-induced "PEEP effect" in 15 critically ill patients under HFJV. VT increased with increasing driving pressure (DP) and decreasing frequency (f) and was influenced little by changes in I/E ratio. CO2 elimination, as reflected by the measurement of PaCO2, was mainly influenced by the absolute level of VT rather than by the product VT X frequency (PaCO2 = 5715/VT, r = 0.75, P less than 0.05). The primary phenomenon explaining HFJV-induced "PEEP effect" was intrapulmonary gas trapping due to incomplete exhalation of the first VT administered: the spontaneous relaxation times of these first VT were longer than expiratory time allotted to the ventilatory settings. HFJV-induced "PEEP effect" increased with I/E ratio, DP, and f and was markedly influenced by the mechanical properties of the total respiratory system. At given ventilatory settings, HFJV-induced "PEEP effect" was greater in patients with a normal or elevated time constant of the total respiratory system (tau RS) than in patients with a low tau RS. These results suggest that HFJV should not be used in patients with chronic obstructive pulmonary disease and asthma, and should be preferentially administered to patients having stiff lungs or decreased chest wall compliance.

Adult↗
PubMed1984

High-frequency jet ventilation vs continuous positive airway pressure for postoperative respiratory support.

In ten patients after recovery from general anesthesia for major vascular surgery, we compared continuous positive airway pressure (CPAP) and high-frequency jet ventilation (HFJV) at the same fractional concentration of oxygen in the inspired gas, both being superimposed on spontaneous breathing. The HFJV was delivered by a ventilator ( Acutronic VS-600) through the lateral lumen of a three-lumen endotracheal tube. Mean airway pressure was increased (3, 8, and 11 mm Hg) by adjusting the driving pressure during HFJV and by the setting of the expiratory valve during CPAP. During HFJV, the frequency (10 Hz) and inspiratory-expiratory ratio (0.25) were kept constant. Control values were measured when patients breathed spontaneously without positive end-expiratory pressure. Cardiac output and transmural filling pressures remained unchanged throughout the study. Neither the arterial oxygen pressure (PaO2) nor intrapulmonary shunt (Qs/Qt) changed significantly during CPAP. The 20- to 30-percent increase in PaO2 and the 5- to 10-percent decrease in Qs/Qt during HFJV when compared to control reflected a slightly but significantly (p less than 0.05) better oxygenation. The increase in arterial carbon dioxide tension was significantly greater during CPAP than during HFJV.

Airway Resistance↗
PubMed1984

Hemodynamic consequences of increasing mean airway pressure during high-frequency jet ventilation.

Six critically ill patients with acute respiratory failure were ventilated using high-frequency jet ventilation (HFJV)-frequency 100.min-1, driving pressure 35 psi, 1.8 mm inside diameter injector cannula. Hemodynamic measurements using radial artery and Swan-Ganz catheters, esophageal pressure (EP), and mean airway pressure (Paw) were measured at four different I:E ratios: 0.25, 0.43, 0.67 and 1.0. Static respiratory compliance, using the super syringe method, was measured during intermittent positive pressure ventilation (IPPV) and during HFJV. The results suggested that decreased venous return, increased right ventricular afterload, and decreased PaCO2 accounted for the decrease in cardiac index observed during HFJV using elevated I:E ratios. These variations, related to marked increases in intrathoracic pressures, are very similar to those observed during conventional ventilation with PEEP.

Adult↗
PubMed1984

Impact of changes in operating pressure during high-frequency jet ventilation.

Fifteen critically ill patients with acute respiratory failure were ventilated with high-frequency jet ventilation (HFJV; frequency 100 breaths/min; I/E ratio 0.43; 1.8-mm internal diameter injector cannula). The patients were divided into two groups according to their initial PaO2 during intermittent positive pressure ventilation at FIO21: in eight patients (group I) the mean PaO2 was 141 +/- 34 mm Hg, and in seven patients (group II) mean PaO2 was 376 +/- 75 mm Hg. During HFJV three different operating pressures were used at random: 1.3, 1.8, and 2.3 bars. Increase in operating pressures significantly decreased PaCO2 and significantly increased mean lung volume above apneic FRC, mean airway pressure, and mean alveolar pressure in both groups. A close relationship was found between variations in mean airway pressure and mean alveolar pressure (r = 0.99, P less than 0.001). Significant increases in PaO2 with increasing operating pressures were observed only in group I. In group II, PaCO2 was significantly lower than in group I for a given operating pressure. We conclude that operating pressure is a main determinant of arterial oxygenation during HFJV because of the concomitant increases in intrathoracic pressures and lung volume. Operating pressure also influences carbon dioxide clearance, PaCO2 varies inversely with operating pressure.

Adult↗
PubMed1983

Effect of analgesia on respiratory muscle function after upper abdominal surgery.

The effects of three methods of analgesia (intravenous morphine, epidural lidocaine and epidural morphine) on vital capacity (VC), forced expiratory volume in 1 s (FEV1) and maximal expiratory and inspiratory pressures (MEP and MIP) at the mouth were studied in 12 high respiratory risk patients following upper abdominal surgery. VC, FEV1, MEP and MIP markedly decreased following laparotomy. VC and FEV1, were partially restored by epidural analgesia and remained unchanged following intravenous morphine. MEP and MIP remained unchanged after each of the three methods of analgesia. This suggests the existence of a non-analgesic dependent dysfunction of inspiratory and expiratory muscles following upper abdominal surgery.

Aged↗
PubMedDate not supplied

Intraperitoneal local anaesthetic for shoulder pain after day-case laparoscopy.

Laparoscopy is frequently associated with postoperative shoulder pain that may last several days. We have assessed the analgesic effect of intraperitoneal local anaesthetics during day-case diagnostic laparoscopy. 80 young women were randomly assigned to one of four groups of 20 patients each: group 1, no peritoneal administration; group 2, 80 ml saline injected under direct vision in the right subdiaphragmatic area at the start of the procedure; group 3, 80 ml 0.5% lignocaine with adrenaline (320,000 dilution); group 4, 0.125% bupivacaine with adrenaline (800,000 dilution). Scapular pain was assessed with a visual analogue pain scale, and information about nausea, vomiting, abdominal pain, and analgesic requirements during the first 48 h was sought. Both local anaesthetics were more effective in reducing postoperative shoulder pain than either control or saline. Analgesic requirements were greater in the non-treatment groups than in the local anaesthetic groups. Intraperitoneal local anaesthetic administration during laparoscopy is both a non-invasive and an efficient method of reducing the intensity of scapular pain.

Adult↗
PubMedDate not supplied

Survey of regional anesthetic practice among French residents at time of certification.

BACKGROUND AND OBJECTIVES: A survey of anesthesia practice was conducted among French residents in anesthesia at the end of their training. This study was performed mainly to evaluate the residents' experience in peripheral nerve blocks. METHODS: Two short clinical cases were proposed to all French residents during a telephone interview immediately before their certification. The first described the case of a young asthmatic patient admitted for an elbow fracture. The second described an elderly woman with severe aortic stenosis admitted for a supracondylar fracture of the femur. A questionnaire had been prepared and was filled in during the interview. Each resident was asked to answer according to the actual choice he or she would have made. For both cases, when general anesthesia was chosen first, the next question was to discuss which regional anesthesia would be used if general anesthesia had to be discarded. In that way, the practical knowledge about most common peripheral nerve blocks learned during residency was investigated. RESULTS: Of 77 residents registered as being at the end of their residency, 8 were on either sabbatical or maternity leave. Regional anesthesia was the first choice in 78% and 57% of cases for the first and second clinical cases, respectively. The regional anesthetic techniques chosen were axillary block (66%), interscalene block (31%), and intravenous regional anesthesia (3%) for case 1 and combined lumbar plexus and sciatic block (36%), epidural anesthesia (30%), single-shot spinal anesthesia (18%), and continuous spinal anesthesia (16%) for case 2. Throughout the residency of the group, 32 +/- 2 axillary blocks, 12 +/- 2 interscalene blocks (axillary vs interscalene, P < .0001), 21 +/- 3 femoral blocks, and 10 +/- 2 sciatic blocks (femoral vs sciatic, P < .0001) had been performed (mean +/- SEM). They had also performed 2.5 +/- 0.5 continuous spinal anesthesias and 17 +/- 3 intravenous regional anesthesias respectively. Upper extremity blocks were more often used during residency than lower extremity blocks (44 +/- 3 vs 31 +/- 4, P < .01). A peripheral nerve stimulator was routinely used by 83% of residents. CONCLUSION: French residents in anesthesiology at time of certification are better trained for peripheral nerve blocks of the upper extremity than for those of the lower extremity. Axillary plexus and femoral nerve block are the most widely used blocks, probably reflecting the techniques the most mastered among teachers. Finally, the extensive use of a peripheral nerve stimulator by residents is probably the result of the widespread use of this device by teachers in France.

Adult↗