Time and laser ranging: a window of opportunity for geodesy, navigation and metrology.

Recent progress in the domain of time and frequency (T/F) standards requires important improvements of existing time distribution links. Among these, the accuracy of time transfer is actually an important part of the concerns in order to establish and maintain time & space references from ground and/or space facilities. Several time transfers by laser link projects have been carried out over the past 10 years with numerous scientific and metrological objectives. Satellite Laser ranging (SLR) has proven to be a fundamental tool, offering a straightforward, conceptually simple, highly accurate and unambiguous observable. Depending on the mission, LR is used to transmit time over two-way or one-way distances from 500 to several millions of km. The following missions and their objectives employed this technique: European Laser Timing (ELT) at 450 km, Time Transfer by Laser Link (T2L2) at 1,336 km, Laser Time Transfer (LTT) at 36,000 km, Lunar Reconnaissance Orbiter (LRO) at 350,000 km, and MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) at tens of million km. This article describes the synergy between SLR and T/F technologies developed on the ground and in space and as well as the state of the art of their exploitation. The performance and sources of limitation of such space missions are analyzed. It shows that current and future challenges lie in the improvement of the time accuracy and stability of the time for ground geodetic observatories. The role of the next generation of SLR systems is emphasized both in space and at ground level, from the point of view of GGOS and valuable exploitation of the synergy between time synchronization, ranging and data transfer.

Preoperative plasma B-type natriuretic peptide (BNP) identifies abnormal transthoracic echocardiography in elderly patients with traumatic hip fracture.

INTRODUCTION: This prospective study was designed to evaluate whether preoperative plasma brain natriuretic peptide (BNP) could identify significant preoperative cardiovascular disease in elderly hip-fractured patients. PATIENTS AND METHODS: Preoperative plasma BNP measurement and rest transthoracic echocardiography (TTE) were performed within 24 h after admission in consecutive hip-fractured patients aged ≥65 years. The major echocardiographic abnormality (MEA) group included patients with at least one TTE abnormality, defined as systolic pulmonary artery pressure (PAP(s)) ≥50 mmHg, left ventricular (LV) systolic dysfunction, increased LV filling pressure (LVFP) or severe valvular disease. The control group included the remaining patients. RESULTS: Seventy-five patients (mean±SD (range) age=85±5 (69-97) years) were included during a 6-month period. Twenty-four (32%) patients constituted the MEA group (17 elevated PAP(s), three LV systolic dysfunctions, 10 increased LVFP, one severe aortic stenosis and one severe mitral regurgitation). Median (interquartile) preoperative BNP value was significantly greater in MEA than in the control group (527 (361) vs. 119 (154) pg ml(-1); p<0.0001). A preoperative plasma BNP cut-off value at 285 pg ml(-1) predicted well MEA with an area under the receiver operating characteristic (ROC) curve equal to 0.895 (p<0.0001) and with a hazard ratio (HR) (confidence interval, CI) of 23.8 (3.7-142.9) (p=0.0008) on multivariate analysis. The presence of MEA or BNP≥285 pg ml(-1) was associated with high mortality. DISCUSSION: The incidence of echocardiographic signs of elevated PAP(s) or elevated LVFP in elderly hip-fractured patients was high. A preoperative BNP value ≥285 pg ml(-1) can discriminate between elderly hip-fractured patients with or without MEA.

[Anaesthesia for caesarean section in a pregnant woman with cor triatriatum]. / Anesthésie pour césarienne chez une patiente porteuse d'une cardiopathie triatriale.

A 41-year-old woman suffering from a left cor triatrium, pregnant for the first time, was hospitalized for a caesarean section in the context of a pulmonary arterial hypertension with severe anaemia. The anaesthetic strategy which was decided on involved setting up a haemodynamic monitoring prior to induction of a general anaesthetia with etomidate, remifentanil and succinylcholine and maintained with propofol, sufentanil and cisatracurium. This strategy allowed the hemodynamic to be stabilized during the operation. The improvement of the arterial pulmonary hypertension immediately after coming out of the operating theatre allowed the patient to be briefly monitored in the intensive care unit and to be allowed home on the 10th day following the operation. The patient's cardiopathy was corrected in the 5th month after the birth.

Occurrence of and risk factors for electroencephalogram burst suppression during propofol-remifentanil anaesthesia.

BACKGROUND: Suppression ratio (SR) derived from bispectral index (BIS) monitoring is correlated to EEG burst suppression. It may occur during deep anaesthesia, but also in the case of metabolic or haemodynamic brain injury. The goal of the study was to describe the occurrence of SR and to determine factors associated with SR during propofol-remifentanil general anaesthesia maintenance. METHODS: We conducted a post hoc analysis of BIS recordings in consecutive patients included in two multi-centre trials, undergoing non-cardiac surgery using a dual closed-loop BIS controller allowing automated propofol-remifentanil administration. The percentage of time spent with a BIS value between 40 and 60 (T(BIS 40-60)) was measured. Two groups of patients were defined: the SR group, including patients with at least one episode of SR value >10% lasting more than 1 min, and the control group. Factors associated with SR were analysed using a stepwise multivariate analysis. RESULTS: A total of 1494 patients [age=57 (17) yr; T(BIS 40-60)=76 (17%)] were analysed and 131 (8.7%) patients constituted the SR group. The main independent factors associated with SR were advanced age [odds ratio (95% confidence interval)=4.80 (1.85-12.43) (P=0.027), 10.59 (3.76-29.81) (P<0.0001), for categories of age 60-80 and >80 yr, respectively], history of coronary artery disease (CAD) [2.53 (1.47-4.37) (P=0.001)] and male gender [1.57 (1.03-2.40) (P=0.03)]. CONCLUSIONS: The occurrence of SR during BIS-controlled propofol and remifentanil anaesthesia is mainly observed in elderly male patients or in patients with a history of CAD. The mechanisms underlying SR and the potential consequences for the patient's postoperative outcome remain unsolved.

[Reporting of muscle relaxant effects in anaesthesia files concerning visceral surgery - a observational and multicenter study]. / Traçabilité de la gestion de l'utilisation des curares dans le dossier d'anesthésie en chirurgie viscérale : une étude observationnelle et multicentrique.

OBJECTIVES: To report any item documenting the peroperative muscle relaxant effects management in anaesthesia files issued from visceral surgery processes. TYPE OF STUDY: Prospective, observational and multicenter. PATIENTS AND METHODS: A single operator analysed 1453 files proposed by nine anaesthetists' teams. The items selected concerned three periods: induction/tracheal intubation, paralysis maintenance, tracheal extubation. Reporting of 40 categories of items was studied. RESULTS: Items related to laryngoscopy and intubation conditions were observed in 43% (0-95) [general average (intercentres min-max)] and in 11% (0-97) of the files, respectively. At least one level of paralysis was reported in 23% (0-96) of the files. For the paralysis maintenance, documentation of an effect appeared in 53% (4-96) of the documents. Neuromuscular assessments preceding the tracheal extubation were retrieved in 43% (12-89) of the notes. Adductor pollicis was concerned for 30% (1-89) of these observations. Detection of level of spontaneous paralysis offset, satisfying to the local standard, appeared in 14% (3-19) of the documents. Pharmacological reversal was noted for 25% (4-67) of the patients; the assessment of the effects so produced was reported in 8% (0-58). CONCLUSION: In the studied collection, the traceability of the peranaesthetic curarization management appears variable on both qualitative and quantitative levels. The emergence of a dedicated guideline - defining the criteria for producing a good documentation of the muscle relaxant use - becomes necessary to secure these practices for all physicians using muscle relaxants.

[About a simple method to prevent accidents caused by changes in positioning in surgery: The transparent head drape]. / Le champ de tête transparent. Un moyen simple de prévention des accidents liés au changement d'installation en chirurgie plastique.

Surgical drapes are a physical barrier between the surgical team's sterile working space (the operating field) and the non-sterile environment of the anaesthesia team and the nursing team within the operating theatre. Once the patient's position has been checked and the skin preparation has been done, they are put in place. They are usually opaque, leaving visible just the areas where the surgical and anaesthesia teams will be working. When the patient's position is changed perioperatively, malpositions may be unnoticed and cause complications. Using a transparent head drape allows one to check the position of the head and upper limbs at all times, thus reducing the risk of complications. It is a simple, easy, economic, non-restrictive method which will produce an improvement in the quality of patient care.

Efficacy and safety of an insulin infusion protocol during and after cardiac surgery.

AIM: Perioperative tight blood glucose (BG) control using insulin therapy after major surgery is a difficult, time-consuming task that also raises some concerns over the risk of severe hypoglycaemia. The aim of the present prospective study was to evaluate the efficacy and safety of an insulin therapy protocol in use at our institution. METHODS: A total of 230 consecutive patients (mean+/-SD age: 67+/-11 years; diabetic patients: n=62) undergoing cardiac surgery (coronary artery bypass grafting: n=137; 20% off-pump) or intrathoracic aortic (n=10) surgery were included. BG control was managed according to an insulin therapy protocol, described by Goldberg et al. (2004) [11], in use for 6 months in our intensive care unit. Insulin infusion rate and frequency of BG monitoring were both adjusted according to: (1) the current BG value; (2) the previous BG value; and (3) the current insulin infusion rate. Efficacy was assessed by the percentage of time spent at the target BG level (100-139 mg/dL) intraoperatively and during the first 2 postoperative days (POD). RESULTS: All patients received postoperative insulin therapy. Patients spent 57.3% and 69.7% of time within the BG target range on POD 1 and 2, respectively. The percentage of time was significantly higher in nondiabetics than in diabetics. Mean BG measurements per patient intraoperatively, on POD 1 and on POD 2 were 4+/-1, 10+/-2 and 7+/-2, respectively. No patient experienced any severe hypoglycaemic events (BG<50mg/dL). CONCLUSION: This study showed that a BG target of 100-139 mg/dL can be safely achieved with an insulin therapy protocol that can be routinely used in everyday clinical practice.

Assessment of topographic brachial plexus nerves variations at the axilla using ultrasonography.

BACKGROUND: The aim of this study was to describe topographic variations in the arrangement of the four main brachial plexus nerves at the junction of the axilla and the upper part of the arm. METHODS: In 153 patients undergoing upper arm surgery using axillary block, we studied nerve arrangements with a three-step approach, combining: (A) cross-sectional ultrasound imaging using a 12 MHz linear ultrasound probe; (B) distal shift of the ultrasound scanhead from the axilla to the elbow joint following the paths of individual nerves; and (C) identifying the distal motor response to electrical nerve stimulation of each nerve. These results were then converted into a 12-section pie chart with the axillary artery (AA) as the axis. RESULTS: The order of the nerves around the AA was median, ulnar, radial, and musculocutaneous in all cases. The most frequent arrangement was observed in 65% of the patients. Five less frequent variations were observed in 4-20% of the patients, with four other variations seen in <2% of the patients. In 78% of the cases, the four nerves were seen separately using static ultrasound imaging. The musculocutaneous nerve was close to the artery in 18% of the patients. CONCLUSIONS: Topographic variations of the four main nerves at the axilla were found to be numerous, the most frequent arrangement being seen in less than two-thirds of the patients. Four separate nerves were seen on static ultrasound imaging at this sectional level of the axilla in only 78% of the cases.

[Information and consent to medical care of the vulnerable individual in France]. / Information et consentement aux soins de la personne vulnérable en France.

Vulnerable individuals, lacking clear understanding, are difficult to inform about medical care and treatment. After a brief recall of the general principles of patient information and consent, we will discuss specific French law protection concerning patients under guardianship. The role in the global process of information and consent of either relatives or surrogate person, witnesses of the patient's views, will be described.

Induction of a melanoma-specific antibody response by a monovalent, but not a divalent, synthetic GM2 neoglycopeptide.

The GM2 ganglioside represents an important target for specific anticancer immunotherapy. We designed and synthesized a neoglycopeptide immunogen displaying one or two copies of the GM2 tetrasaccharidic moiety. These glycopeptides were prepared using the Huisgen cycloaddition, which enables the efficient ligation of the alkyne-functionalized biosynthesized GM2 with an azido CD4(+) T cell epitope peptide. It is worth noting that the GM2 can be produced on a gram scale in bacteria, which can be advantageous for a scale-up of the process. We show here for the first time that a fully synthetic glycopeptide, which is based on a ganglioside carbohydrate moiety, can induce human tumor cell-specific antibodies after immunization in mice. Interestingly, the monovalent, but not the divalent, form of GM2 peptide construct induced antimelanoma antibodies. Unlike traditional vaccines, this vaccine is a pure chemically-defined entity, a key quality for consistent studies and safe clinical evaluation. Therefore, such carbohydrate-peptide conjugate represents a promising cancer vaccine strategy for active immunotherapy targeting gangliosides.

Glycaemic dysregulation in nondiabetic patients after major lower limb prosthetic surgery.

AIM: Blood glucose (BG) dysregulation is common after cardiac surgery, but remains poorly described after major noncardiac surgery. The aim of this prospective observational study was to analyze perioperative changes in BG levels in nondiabetic patients undergoing major arthroplasty. METHODS: Nondiabetic consenting patients scheduled for hip or knee arthroplasty were eligible. BG levels were assessed from the preoperative period to the end of postoperative day 2. Oral feeding was resumed from the evening after surgery. Hyperglycaemia, defined as two sequential BG measurements that were either greater than 7.0 mmol/L during the fasting period or greater than 11.1 mmol/L 2 hours after a meal, was the primary outcome variable. Two groups of patients were identified, depending on the occurrence or not of hyperglycaemia (hyperglycaemic and normoglycaemic groups, respectively). Patients were followed-up for surgical wound infection for one year postoperatively. RESULTS: Thirty-eight patients, aged 65+/-14 years (mean+/-S.D.), were included. A significant increase in BG was observed during the fasting period (Anova, P<0.001), and 74% of patients met the primary outcome variable. In the hyperglycaemic group, the mean number of BG measurements per patient above the thresholds was 5.6+/-2.8, and 58% of the patients still had a postmeal BG level greater than 11.1 mmol/L at the end of the study period. No surgical wound infection was observed at follow-up. CONCLUSION: This study showed that nearly 75% of nondiabetic patients experience a moderate, but significant, increase in either fasting or postprandial BG levels in the first two days following major arthroplasty.

[Ropivacaine infiltration during breast cancer surgery: postoperative acute and chronic pain effect]. / Infiltration de ropivacaïne en chirurgie carcinologique du sein: effet sur la douleur postopératoire aiguë et chronique.

OBJECTIVES: Decrease acute pain after breast cancer surgery by an infiltration of ropivacaine. Analyse effect on chronic pain. STUDY DESIGN: Prospective randomised double blind versus placebo study. PATIENTS AND METHODS: Eighty-one patients randomised between two groups received wound infiltration with 40 ml of ropivacaine 4.75 mg/ml or placebo. Acute pain was assessed during 24h with analogical visual scale and antalgic consumption. One year later, telephonic interviews looked for chronic pain and evaluate it with McGill Pain Questionnaire. RESULTS: Analogical visual scale pain score, antalgic consumption and chronic pain incidence were similar between groups. CONCLUSION: Ropivacaine scar infiltration provided no acute or chronic pain relief after breast cancer surgery.

[Takotsubo syndrome: a young woman case]. / Un syndrome de Takotsubo chez une patiente jeune.

After induction of anaesthesia for lumbar disc herniation surgery, an ASA-1, 39-year-old woman presented an acute heart failure. A persistent hypotension with tachycardia was observed after a brief hypertension peak during orotracheal intubation. After electrocardiogram, echocardiogram and biologic dosages, the diagnosis seems to be coronary ischemia. Coronarography was normal; takotsubo syndrome diagnosis was made with typical ventriculographic aspect. Evolution at two days and one month was favorable.

[Life-threatening postpartum hemorrhage and recombinant activated factor rFVIIa NovoSeven use]. / Hémorragie de la délivrance "menaçant la vie" et utilisation du facteur VII recombinant activé rFVIIa NovoSeven.

Postpartum haemorrhage remains a dangerous obstetrical complication, which is the main cause of maternal mortality in developing countries. The diagnosis must be immediate and its management is both medically and surgically in life-threatening haemorrhage. We present a case of a thirty-three-year-old woman who asked a pregnancy interruption for premature rupture of membranes at 21(th) gestational week for her second pregnancy; she underwent a caesarean section at term for her first pregnancy. She delivered vaginally and developed a postpartum haemorrhage with hemorrhagic shock which was resistant to medical, surgical and radiological management. We decided to use recombinant activated factor VII (rFVIIa, NovoSeven) as a final attempt to rescue the patient. During surgery, two intravenous bolus injections (60, 120 mug/kg) were successfully given with a control of bleeding and haemoglobin. The patient developed later a splenic thrombosis that can be related to either rFVIIa or to the hypovolemic shock or to the sepsis. Recombinant activated factor VII is an interesting and promising haemostatic agent in the management of life-threatening postpartum haemorrhage unresponsive to conventional treatment.

The decrease of fibrinogen is an early predictor of the severity of postpartum hemorrhage.

BACKGROUND: Postpartum hemorrhage (PPH) is a major source of maternal morbidity. OBJECTIVES: This study's objective was to determine whether changes in hemostasis markers during the course of PPH are predictive of its severity. PATIENTS AND METHODS: We enrolled 128 women with PPH requiring uterotonic prostaglandin E2 (sulprostone) infusion. Two groups were defined (severe and non-severe PPH) according to the outcome during the first 24 hours. According to our criteria, 50 of the 128 women had severe PPH. Serial coagulation tests were performed at enrollment (H0), and 1, 2, 4 and 24 hours thereafter. RESULTS: At H0, and through H4, women with severe PPH had significantly lower fibrinogen, factor V, antithrombin activity, protein C antigen, prolonged prothrombin time, and higher D-dimer and TAT complexes than women with non-severe PPH. In multivariate analysis, from H0 to H4, fibrinogen was the only marker associated with the occurrence of severe PPH. At H0, the risk for severe PPH was 2.63-fold higher for each 1 gL(-1) decrease of fibrinogen. The negative predictive value of a fibrinogen concentration >4 gL(-1) was 79% and the positive predictive value of a concentration