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Biomedical subjects

D Safran

Publications and source records attributed to D Safran.

At least 19 recordsLinked to original sources
PubMed2000

[Equipment surveillance of implantable catheter ports (1996-1998). Members of Sub-Commissions 4a and 4b for Equipment Surveillance].

We analyse all incident reports to the French Health Ministry over the 1996-1998 period, concerning implantable catheter ports. They represent 7% of all reports in the field of anaesthesia and intensive care. Two hundred eleven reports have been analysed. There were 93 catheter ruptures with 77 intravascular migrations. In more than 50% of cases, a pinch-off syndrome mechanism was responsible of these ruptures and a displacement of the O'ring was involved in 25%. Additional minor complications were reported and discussed in regard to literature. We conclude that implantable catheter ports may lead to serious incidents which are preventable in most cases.

Catheters, Indwelling↗
PubMed1999

[Daily medical device surveillance].

In France the manufacturer, the user of a medical device and all those informed of an event or a risk for an event caused by the device and resulting in death or the deterioration of the health status of a patient must declare the event without delay to the appropriate administrative authority. The witness of the event informs either the local correspondent for materiovigilance, when available, or the ministry directly. A major objective of the local correspondent is to act as a filter and to select among the declarations of events those to be transmitted without delay or quarterly to the ministry, and those to be registered only locally. Within 48 hours the ministry: a) returns an acknowledgement with instructions how to proceed with the involved device; b) communicates the declaration to the chairman of the ad hoc subcommission; c) informs the manufacturer of the device. The chairman decides on the degree severity (major event requiring an immediate investigation, event requiring an investigation, event to be entered in a follow-up programme). In the first two cases an investigation is undertaken by one or several members of the subcommission in co-operation with the manufacturer and the declarant of the event. Conservative measures can be undertaken to prevent the re-occurrence of an event either with the involved and/or with similar devices and to facilitate the investigation.

Equipment Failure↗
PubMed1999

Pneumopericardium mimicking acute myocardial ischemia after laparoscopic cholecystectomy.

Pneumopericardium occurred after laparoscopic cholecystectomy in a 57-year-old woman. The patient had chest pain accompanied by T-wave inversion on electrocardiogram, with signs and symptoms suggestive of acute myocardial ischemia. Evaluation for myocardial infarction, however, was negative and clinical findings resolved spontaneously. Although pneumopericardium after laparoscopic procedures has been previously reported, this case illustrates how associated findings may mimic those of acute myocardial ischemia or infarction.

Chest Pain↗
PubMed1999

[Accessory anesthetic breathing systems: verification before use].

Accessory or ancillary anaesthesia breathing systems can be defined as all those connected to the fresh gas outlet of the anaesthetic apparatus and used instead of the circle system associated with the ventilator, which is the main circuit. They include: the Mapleson systems, the systems with a nonrebreathing valve and the disposable systems with a carbon dioxide absorber. They can be a cause of major accidents when not checked before and monitored during use. This technical note describes techniques of preanaesthetic checking and monitoring during anaesthesia.

Anesthesia, Closed-Circuit↗
PubMed1998

Functioning parathyroid cyst.

Cystic lesions of the parathyroid gland associated with hyperparathyroidism are decidedly uncommon and may lead to confusion when appropriate work-up and therapy are instituted. A case of a functioning parathyroid cyst is presented, followed by a concise review of pertinent literature and recommendations for diagnostic and therapeutic interventions.

Aged↗
PubMed1998

[Hemofiltration during severe sepsis or multiorgan failure syndrome].

Continuous renal replacement therapy (CRRT) has been used in intensive care units particularly in patients with sepsis or multiorgan failure. In comparison to intermittent haemodialysis, hemofiltration techniques offers an improved hemodynamic tolerance, related to the absence of osmotic pressure gradient. Indeed, hemofiltration is based on the physical principle of convection to remove substances from the plasma. The removal of substances that are released during sepsis, acute respiratory distress syndrome or multiorgan failure may be of particular interest. Several human studies have demonstrated that hemofiltration removes various inflammatory mediators, but the clinical significance of this removal remains questionable. If this removal occurs predominantly by convection, interest in hemofiltration will focus on high volume hemofiltration in order to obtain maximal ultrafiltrate flows. Patients with sepsis or multiorgan failure require close monitoring of most vital functions. The use of a CRRT technique emphasizes the importance of this monitoring and adds new monitoring issues relative to fluid balance, anticoagulation, hypothermia or drug removal.

Cytokines↗
PubMed1996

High-volume, zero-balanced hemofiltration to reduce delayed inflammatory response to cardiopulmonary bypass in children.

BACKGROUND: In previous studies, researchers suggested a beneficial role of hemofiltration performed during cardiopulmonary bypass in children. This study was performed to assess both clinical effects and inflammatory mediator removal by high-volume, zero-fluid balance ultrafiltration during rewarming (Z-BUF). METHODS: Twenty children undergoing cardiac surgery were assigned randomly to Z-BUF or a control group. Plasma C3a, interleukin (IL)-1, IL-6, IL-8, IL-10, tumor necrosis factor, myeloperoxidase, and leukocyte count were measured before (T1) and after (T2) hemofiltration and 24 h later (T3). The intensive care unit staff was blinded to the patient's group. Postoperative alveolar-arterial oxygen gradient, time to extubation, body temperature, and postoperative blood loss were monitored. RESULTS: Ultrafiltration rate was 4,972 (3,183-6,218) mL/m2 (median [minimum-maximum]) in the Z-BUF group, where significant reductions were observed in postoperative blood loss, time to extubation (10.8[9-18] vs. 28.2 [15-58] h) and postoperative alveolar-arterial oxygen gradient (320 [180-418] vs. 551 [485-611] mmHg at T3). In the Z-BUF group, significant removal of tumor necrosis factor, IL-10, myeloperoxidase, and C3a were observed at T2. Interleukin 1, IL-6, IL-8, and myeloperoxidase were decreased at T3, suggesting earlier removal of factor(s) that may trigger their release. CONCLUSIONS: These results suggest that hemofiltration exerts some beneficial clinical effects that are not due to water removal. The role of the early removal of factors triggering the inflammatory response, rather than a direct removal of cytokines, deserves further investigation.

Anesthetics↗
PubMed1995

[Ventilators for anesthesia. Models available in France. Criteria for choice].

This update article discusses the criteria for the choice of an anaesthetic machine and provides a short analysis of the main components of the models commercialized in France in 1994. The following items are considered: the design of the machine, the fresh gas delivery system, the anaesthesia breathing system(s), the ventilator and the waste gas scavenging system, the monitors associated with the machine and other criteria such as facility of learning to run the machine and of its daily use, ease of "in-house" maintenance and quality of after-sales service, cost of the machine and of its use (driving gas, disposable equipment).

Anesthesia, Inhalation↗
PubMed1994

Assessment of coagulation factor activation during cardiopulmonary bypass with a new monoclonal antibody.

Antithrombin-III (AT) is a key inhibitor of blood coagulation that neutralizes activated serine esterases by forming covalent modified complexes (ATm). A new monoclonal antibody directed against short-lived AT-activated serine protease complexes provides a means of measuring subclinical coagulation activity during cardiopulmonary bypass (CPB). Twelve patients undergoing CPB for coronary artery bypass grafting were studied and AT, ATm, D-dimers (DD), and several other coagulation and fibrinolytic markers were measured during the surgical procedure. There were decreases in AT, factors V, II, X, IX, protein S (total and free), C4b-binding protein, thrombomodulin, and platelets counts, whereas heparin, ACT, thrombospondin, plasminogen activator inhibitor (PAI-1), and tissue plasminogen activator (tPA) increased. ATm and the percentage of ATm available (ATm/AT) showed a peak during CPB. These results demonstrate that during CPB, the use of heparin produces an equilibrium involving increased coagulation activation and consumption in association with increased fibrinolysis. The equilibrated consumption of both coagulation and fibrinolytic factors leads to low levels of all factors after cardiac surgery. The ATm assay allows assessment of the differential effects of CPB and surgical trauma on coagulation activation. It is speculated that ATm levels may be useful in monitoring the consumption of coagulation factors.

Adult↗
PubMed1994

Hemofiltration during cardiopulmonary bypass in pediatric cardiac surgery. Effects on hemostasis, cytokines, and complement components.

BACKGROUND: This prospective study was intended to determine in a homogeneous population of children whether hemofiltration, performed during cardiopulmonary bypass rewarming, is able to improve hemodynamics and biologic hemostasis variables, to reduce postoperative blood loss, time to extubation, and plasma cytokines, and complement fragments. METHODS: Thirty-two children undergoing surgical correction of tetralogy of Fallot were randomly assigned to a hemofiltration or control group. Hemofiltration was performed with a polysulphone hemofilter during rewarming of cardiopulmonary bypass. Plasma clotting factors, D-dimers, antithrombin-III, complement fragments C3a and C5a, interleukin-1 beta, interleukin-6, interleukin-8, and tumor necrosis factor-alpha were measured before and after hemofiltration. Systemic mean arterial pressure, left atrial pressure, time to extubation, and postoperative blood loss were monitored. RESULTS: In the hemofiltration group, significant reductions in 24-h blood loss (250 (176-356) vs. 319 (182-500) ml/m2, median (minimum-maximum), time to extubation (15 (9-22) vs. 19 (11-24) h), plasma concentrations of C3a, C5a, interleukin-6, and tumor necrosis factor-alpha were observed compared to control. Arterial oxygen tension on admission to the intensive care unit was significantly greater in the hemofiltration group (136 +/- 20 vs. 103 +/- 25 mmHg, mean +/- SD). Significant increases in mean arterial pressure, clotting factors, and antithrombin-III were noted for the hemofiltration group. No intergroup difference was observed in left atrial pressure, platelets count, D-dimers, interleukin-8, and duration of stay in the intensive care unit. CONCLUSIONS: Hemofiltration during cardiopulmonary bypass in children improves hemodynamics and early postoperative oxygenation and reduces postoperative blood loss and duration of mechanical ventilation. Hemofiltration is able to remove some major mediators of the inflammatory response.

Cardiopulmonary Bypass↗
PubMed1994

Inhaled nitric oxide as a therapy for pulmonary hypertension after operations for congenital heart defects.

Seventeen infants were treated with inhaled nitric oxide for critical pulmonary artery hypertension after operations for congenital heart defects. In all 17 patients conventional medical therapy consisting of hyperventilation, deep sedation/analgesia, and correction of metabolic acidosis had failed. All children were monitored with a transthoracic pulmonary artery catheter inserted at operation. Pulmonary artery hypertension was defined as an acute rise in pulmonary pressure associated with a decrease in oxygen arterial or venous saturation. After failure of conventional medical therapy, 20 ppm of inhaled nitric oxide was administered to the patient. In all patients the pulmonary pressures decreased (mean pulmonary arterial pressure decreased by -34% +/- 21%) without significant change in systemic arterial pressure, whereas the oxygen arterial saturation and oxygen venous saturation increased by 9.7% +/- 12% and 37% +/- 28%, respectively. Fifteen children were discharged from the intensive care unit at 10 +/- 6 days (range 3 to 26 days) and two died. This study demonstrates that inhaled nitric oxide exerts a selective pulmonary vasodilation without decreasing systemic arterial pressure in children with congenital heart disease. The increased values of mixed venous oxygen saturation and urinary output suggest that this selective lowering of pulmonary vascular resistance improved the overall hemodynamics. The potential toxic effects of nitric oxide and nitrogen dioxide necessitate careful consideration of the risks and benefits of inhaled nitric oxide therapy.

Acute Disease↗
PubMed1993

[Continuous monitoring of mixed venous blood oxygen saturation].

Mixed venous oxygen saturation (SvO2), measured on pulmonary artery blood, is a convenient indicator of matching between O2 transport (TaO2) and O2 body consumption (VO2). The measurement technique is based on the haemoglobin reflection spectrophotometry principle using two or three wave lengths. The Fick principle points out that SvO2 depends on five parameters: SvO2 = SaO2 - (VO2/CI x Hb x PO) where SaO2, CI and PO respectively represent arterial O2 saturation, cardiac index and O2 affinity. SvO2 does not always reflect tissue O2 tension: when considering a given value of SvO2, PvO2 will depend upon the position of the oxyhaemoglobin dissociation curve. It is impossible to establish in the absolute a "normal" value of SvO2. However, in most clinical circumstances, an SvO2 ranging from 60 to 80% attests that O2 tissue delivery is appropriate. Under certain conditions a continuous monitoring of SvO2 allows to assess another index such as ventilation-perfusion index or the O2 tissue extraction index. Usually SvO2 variations are more informative than the absolute SvO2 value. However, their interpretation should be cautious. First and foremost, the ability of each of the four main SvO2 determinants to influence the SvO2 is unequal as the numerical ranges of variation of these determinants are very different. Moreover, the attribution of a variation of SvO2 to one of its determinants implies that each of them is independent from the others, a feature which is very rarely seen in clinical practice. Finally as the mathematical relationship between SvO2 and its determinants is linear (SaO2 and VO2), or hyperbolic (CI and Hb), the weight of SaO2 or VO2 is independent of their absolute value, whereas CI or Hb weights will depend on their value. The limits of SvO2 monitoring are linked first to the occurrence of an anaerobic metabolism state when TaO2 becomes too low; SvO2 then just provides informations on the aerobic part of the metabolism. Moreover, SvO2 is just a global indicator for tissue O2 oxygenation status which does not give any indication about regional flow distribution. Therefore, SvO2 enables systemic imbalance supervision only. Finally, the existence of a right-to-left shunt will modify the SvO2 values through various mechanisms. However the SvO2 measured, in the pulmonary artery, remains reliable, whereas the presence of a left-to-right shunt will highly alter SvO2 basal value, only its time course remaining significant. SvO2 monitoring, element of diagnosis and monitoring, as well as a warning signal, has a priori specific indications poorly assessed, so far. (ABSTRACT TRUNCATED AT 400 WORDS)

Cardiac Surgical Procedures↗