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Biomedical subjects

F Lagneau

Publications and source records attributed to F Lagneau.

17 recordsLinked to original sources
PubMed2006

[Organization of urgent blood transfusion in France: analysis of practice patterns in centers involved in care delivery to multiple trauma patients].

OBJECTIVE: To describe the organization of medical and transfusion services within the framework of hospital admission for multiple trauma. STUDY DESIGN: National survey in France. MATERIAL AND METHODS: All French hospitals caring for multiple trauma patients were sent a questionnaire. Organization of the medical and transfusion services, and their related resources were evaluated. RESULTS: Among 372 questionnaires sent, 116 replies were received from structures which care for 18 (1-500) multiple trauma patients each year. An orthopaedic and an abdominal surgery unit were widely available whereas a neurosurgeon was available in 21% of responding centers. A transfusion site was found in 43%, whereas others have either a deposit for distribution to specific patients (40%) or a small deposit to cover urgent situations (17%). Comparison with legal or expert based rules of adequate transfusion process disclosed a variable incidence of practice dysfunctions (2-49%) depending on the parameter assessed. CONCLUSION: The French organization of multiple trauma patients' care and blood transfusion delivered for these patients is not homogenous. Dysfunctions were found in all types of hospitals. Recommendations describing good practice seem necessary to be built at the national level.

Blood Transfusion↗
PubMed2006

Embolic and bleeding events after modified Bentall procedure in selected patients.

AIM: As valve-sparing procedures gain increasing popularity, the long-term results of the total aortic root replacement (TARR) were evaluated using mechanical valve grafts in selected patients. METHODS AND RESULTS: From January 1993 to December 2003, 100 patients (87 men), aged >65 years (mean 51 (SD 10.4 years), presenting with isolated aortic root dilatation with or without aortic valve insufficiency, undergoing elective root replacement using a mechanical valve graft were reviewed. The aetiology of aortic root disease was degenerative in 69 patients and related to the bicuspid aortic valve in 31 patients. In 11 patients, concomitant coronary artery bypass graft was performed. Hospital mortality was 4%. Overall survival was 93.9% (2.4%), 89.1% (3.5%) and 83.2% (5.2%) at 1, 5 and 7 years, respectively. 14 patients experienced 45 embolic events (3.21 (2.64) events/patient; range: 1-10 events). Thus, the linearised rate of embolic events was 10.3 per 100 patient-years (95% confidence interval (CI) 7.29 to 13.31). The actuarial embolism-free survival was 96.6% (1.9%), 77.1% (6%) and 74.3% (6.4%) at 1, 5 and 7 years, respectively. The linearised rate of bleeding events was 2.2 per 100 patient-years (95% CI 0.87 to 3.71). Actuarial bleeding free survival was 95.6% (2.1%), 93.2% (2.6%) and 87.7% (5.8%) at 1, 5 and 7 years. respectively. None of the patients required reoperation and no cases of structural or non-structural valve dysfunction were observed. CONCLUSIONS: TARR using mechanical valve grafts yields excellent survival results in selected patients. However, a high rate of minor thromboembolic events was recorded. Aspirin in combination with oral anticoagulants might be of potential interest in these patients.

Adolescent↗
PubMed2004

[Clinical applications of intravenous anaesthetics pharmacology: the example of hypnotics and opioids].

OBJECTIVE: To review the general principles of pharmacokinetics and pharmacodynamics models by focusing on intravenous anaesthetics (hypnotics and opioids). DATA SOURCES: Medline references, lectures from the French congress of anaesthesiology and intensive care medicine, abstracts. DATA SYNTHESIS: Pharmacokinetic and pharmacodynamic modelling allows simple estimation of becoming of anaesthetic drugs in the body, instead of classical pharmacologic approach. However, pharmacokinetic as well as pharmacodynamic parameters are often considered as resulting from complex mathematic approaches and remain then poorly used in practice by physicians. The aim of this article is to simply expose concepts underlying PK-PD models building and to explain significance of the main PK-PD parameters (first-order rate constants, k(e0), T(1/2)k(e0), T(peak), context-sensitive half-time, context-sensitive decrement times). Clinical consequences for using intravenous anaesthetic drugs (hypnotics and opioids) are exposed either during bolus injection or continuous infusion, when injected alone or co-administered.

Anesthesia, Intravenous↗
PubMed2001

The interpretation of train-of-four monitoring in intensive care: what about the muscle site and the current intensity?

OBJECTIVES: To investigate the effect of current intensity and choice of the stimulated muscle group on train-of-four (TOF) interpretation in the intensive care unit (ICU). DESIGN AND SETTING: Intervention study in a surgical intensive care unit. PATIENTS: 13 ventilated patients requiring prolonged muscle relaxation. MEASUREMENTS AND RESULTS: Prior to blockade TOF responses of left and right orbicularis oculi, adductor pollicis, and plantar flexors were recorded by setting the current intensity at 20, 40, 60, and 80 mA. The minimal current intensity (MCI) providing a supramaximal response was then identified for each muscle. Cisatracurium was then infused aiming to continuously observe a TOF at 2/4 on the left orbicularis oculi at 40 mA. The responses to TOF on all the muscle sites were further recorded at 40, 60, and 80 mA when the endpoint was reached for the first time, and after a 48-h infusion. After cessation of infusion the delay to observe 4/4 responses at TOF was recorded at each site at 40 mA or at MCI if MCI was above 40 mA. MCI did not differ between muscle groups. When the fixed endpoint was reached for the first time on left orbicularis oculi, the TOF response at 40 mA on right orbicularis oculi differed significantly. In contrast, no difference was observed between left and right sides at 40 mA at the other sites, nor at any sites at 60 and 80 mA. The TOF response on orbicularis oculi (left and right sides together) was different at 40 mA, compared to 60 and 80 mA. TOF responses at orbicularis oculi at 60 or 80 mA significantly differed from responses on adductor pollicis or plantar flexor, orbicularis oculi being less sensitive to cisatracurium than adductor pollicis or plantar flexor. After a 48-h infusion the same differences in sensitivities were observed between the muscle groups. At any current intensity the recovery was slower at adductor pollicis than at orbicularis oculi or plantar flexor. CONCLUSIONS: For a good TOF interpretation in the ICU the current intensity should be tested before onset of blockade. The orbicularis oculi is less sensitive to cisatracurium than adductor pollicis and plantar flexor both at onset and after a prolonged infusion. The recovery from relaxation is faster on orbicularis oculi and plantar flexor than on adductor pollicis.

APACHE↗
PubMed2001

The pharmacokinetics of cisatracurium in patients with acute respiratory distress syndrome.

UNLABELLED: Continuous neuromuscular blockade is often necessary in patients being treated for acute respiratory distress syndrome (ARDS) to optimize oxygenation. In this study, neuromuscular blockade (no response to two responses at the train-of-four stimulation at the orbicularis oculi muscle) was achieved in six patients with ARDS by a continuous infusion of cisatracurium. The plasma concentration of cisatracurium during the infusion averaged 1.00 (0.25-1.45) microg/mL, expressed as median (range). The clearance and half-life were 6.5 (3.3-7.6) mL. min(-1). kg(-1) and 25 (16-48) min, respectively. The laudanosine plasma concentrations were 0.70 (0.12-1.20) microg/mL. The pharmacokinetic variables of cisatracurium are similar to those of patients without organ failure undergoing elective surgery. Plasma laudanosine levels always remained well less that those associated with seizure activity in animal models. Long-term infusion of cisatracurium was not associated with any side effects. Cisatracurium is a suitable muscle relaxant when deep and continuous levels of muscle relaxation are required in patients treated for ARDS. IMPLICATIONS: We studied the pharmacokinetics of cisatracurium in six patients treated for respiratory distress syndrome by continuous muscle relaxation. A deep degree of neuromuscular blockade corresponding to abolition of two responses at the orbicularis oculi to train-of-four stimulation was obtained in all patients. The pharmacokinetic variables observed in these severely ill patients were similar to those of anesthetized patients. No accumulation of laudanosine was seen. Cisatracurium appears to be suitable when continuous muscle relaxation is required in critically ill patients.

Adult↗
PubMed1999

Fluid therapy directly interferes with immunoassay for cardiac troponin I.

OBJECTIVE: To investigate interference in cardiac troponin I (cTNI) immunoassay induced by some widely used loading fluids. SETTING: A biochemistry unit of a university hospital. MEASUREMENTS AND RESULTS: Human serum with a cTNI concentration of 0.32 microg/l was diluted at 10, 20, 40, and 80% with saline serum (SS), Plasmion (P) (a modified fluid gelatin), hydroxyethyl starch (HES), and 20% human albumin (Alb). Serum with a cTNI concentration of 1.29 microg/l was diluted at 20, 40, 60, and 80%. Four samples with increasing cTNI concentrations (from 0 to 8.14 microg/l) were diluted at 80% with the four fluids. Differences (delta-C) between expected concentrations resulting from the dilutional effect and those measured with the Access cTNI immunoassay were expressed in microg/l. Statistical analysis was performed using a nonparametric test. No false positivity was observed. At a low cTNI concentration (0.32 microg/l), interference was observed with SS and HES at 40 and 80% dilution and with P and Alb at 80%. When cTNI was 1.29 microg/l, interference was observed with each fluid at a dilution of 20% and increased with the increase in dilution. The highest interference was observed with HES, the lowest with P. When the dilution was at 80% for increasing concentrations of cTNI, the higher the initial cTNI was the higher the interference appeared, mostly with SS and HES. CONCLUSIONS: SS, P, Alb, and HES interfere in this cTNI immunoassay. This interference is higher with SS and HES and is higher when the percentage of hemodilution or real cTNI concentration increases.

Fluid Therapy↗
PubMed1999

Effect of mild hypothermia on the vascular actions of phenylephrine in rat aortic rings.

Intraoperative mild hypothermia is common. We have investigated the effects of mild hypothermia (34 vs 38 degrees C) on phenylephrine--(10(-8) to 10(-5) mol litre-1) induced contractions of rat aortic rings mounted for isometric tension recordings. A marked decrease in Emax (maximal tension) (P < 0.05) and significant increase in EC50 (phenylephrine concentration producing 50% of maximal tension) were observed at the lower temperature in endothelium intact rings, but there was no effect of temperature when the endothelium had been removed. The decreased contraction with hypothermia in the endothelium intact vessels was restored to 84% by administration of the nitric oxide synthase inhibitor L-NNA and a small additional amount of tone was restored in the presence of the cyclooxygenase inhibitor, indomethacin. We conclude that mild hypothermia markedly decreased phenylephrine-induced rat aortic contraction in vitro by endothelium dependent mechanisms, largely related to increased nitric oxide production or action.

Animals↗
PubMed1998

Vascular properties of isoflurane: comparison between normal and cirrhotic rats.

Isoflurane is known to dilate blood vessels and to modulate nitric oxide production. Because cirrhosis is characterized by over production of endothelial nitric oxide, isoflurane-induced vasodilatation may be altered in this situation. We have compared the vasodilator effects of isoflurane in normal rats and rats with secondary biliary cirrhosis. Aortic rings (intact or endothelium denuded) from normal and cirrhotic rats were suspended in HEPES solution and preconstricted with KCl 40 mmol litre-1. Isoflurane dose-dependently relaxed vessels in both groups. Maximal relaxation was comparable between normal and cirrhotic rats in intact (mean 80 (SEM 4) vs 81 (6)%; ns) and in denuded (100 (4) vs 95 (5)%; ns) vessels. Intact vessels relaxed more than denuded vessels in both groups (100 (4) vs 80 (4)% (P = 0.0008) in normal rats and 95 (5) vs 80 (6)% (P = 0.0008) in cirrhotic rats). We conclude that cirrhosis did not modify isoflurane-induced vasodilatation and that the modulator effect of endothelium was conserved.

Anesthetics, Inhalation↗
PubMed1997

Role of endothelium in the modulation of isoflurane-induced vasodilatation in rat thoracic aorta.

The mechanisms by which endothelium attenuates vasodilation caused by isoflurane are not well understood. We examined the role of endothelium-derived substances, nitric oxide (NO), endothelium-derived hyperpolarizing factors (EDHF), prostanoids and endothelins in the response to isoflurane in rat thoracic aorta. Increasing cumulative concentrations of isoflurane were administered to aortic rings suspended in Hepes solution and preconstricted with either phenylephrine 10(-6) mol litre-1 or KCl 40 mmol litre-1 (which inhibit EDHF). Rings were intact, denuded or incubated with an inhibitor of nitric oxide synthesis (N omega-nitro-L-arginine (LNNA 5 x 10(-5) mol litre-1), an inhibitor of prostanoid synthesis (indomethacin 10(-5) mol litre-1) or a blocker of the vascular receptors to endothelins (cyclo (-D-trp-D-Asp-Pro-D-Val-Leu (BQ 123 10(-5) mol litre-1)- Endothelium attenuated isoflurane-induced vasodilation in KCl-constricted rings at concentrations of 4% (mean 95 (SEM 4)% vs 72 (4)%; P = 0.0005) and 5% (100 (4)% vs 80 (4)%; P = 0.0008) and in phenylephrine constricted rings at concentrations of 4% (54 (8)% vs 35 (3)%; P = 0.04) and 5% (78 (10)% vs 49 (5)%; P = 0.03). Relaxation was significantly greater in rings treated with LNNA than in intact rings at concentrations of 4% (85 (4)% vs 72 (4)%; P = 0.0005) and 5% (90 (4)% vs 80 (4)%; P = 0.0008). Indomethacin and BQ 123 did not alter isoflurane-induced vasodilation. We conclude that endothelium attenuated the vasodilator effect of isoflurane by a mechanism which was abolished by inhibition of nitric oxide. We hypothesize that isoflurane inhibits the release of nitric oxide, leading to a relative vasoconstriction counter-balancing its vasodilator effect. In contrast, EDHF, prostanoids and endothelins were not involved in the attenuation of isoflurane-induced vasodilatation.

Anesthetics, Inhalation↗