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Biomedical subjects

N Nathan

Publications and source records attributed to N Nathan.

At least 19 recordsLinked to original sources
PubMed2005

[Analgesic effect of continuous intravenous nefopam after urological surgery].

OBJECTIVES: To evaluate the efficacy of continuous infusion of nefopam. Indeed this analgesic is commonly used by continuous infusion by many anaesthetists to reduce its adverse effects. However whether the analgesic effect of an intermittent administration of nefopam has been proven, the efficacy of continuous infusion has not been established. STUDY DESIGN: Double-blind placebo controlled prospective randomised study. PATIENTS AND METHODS: Sixty patients ASA 1 to 3 undergoing planned urological surgery with laparotomy were included. At the end of surgery, bolus doses of placebo (Group 3) or nefopam 20 mg (Group 1 and 2) were administered to all the patients. Placebo (Group 3), nefopam 80 mg (Group 1) or 120 mg (Group 2) was thereafter continuously infused over 24 hours. All patients received additional analgesia with PCA morphine. We measured pain at rest and on cough with VAS. Adverse side effects such as nausea and vomiting, sedation and respiratory depression were evaluated. Mental performance was measured with mini mental status tests. RESULTS: Patients were older in the placebo group by approximately six years but anesthetic and surgical variables were not different between groups. Pain at rest and on cough was not statistically different between groups. In the placebo group, the median (interquartile range) morphine consumption reached 29 mg (13-53) whereas in patients receiving 80 and 120 mg nefopam, it levelled to 44 mg (11-54) and 35 mg (9-82) respectively (p > 0.05). Patients needed morphine during the same time period whether they received nefopam or not. Patients suffering from adverse effects were similar between groups. CONCLUSION: In this study, continuous administration of nefopam did not reduce morphine consumption nor ameliorate analgesia and thus may not be recommended in urological surgery. Nefopam pharmacokinetics when used with continuous infusion as well as surgery types and differences in age between groups may explain these results.

Aged↗
PubMed2004

[Postoperative nausea and vomiting: cost and therapeutic algorithm. Part II: high-risk patients and late PONV].

OBJECTIVES: To evaluate in high-risk patients and in usual clinical conditions, the efficiency of treatments based on an algorithm on late (24 h) postoperative nausea and vomiting (PONV). STUDY DESIGN: Prospective and descriptive. METHODS: The nature and efficiency of prophylactic and curative PONV treatments was evaluated 24 h after surgery under general anesthesia in patients at high risk of PONV, one and 15 month after the introduction of a clinical and therapeutic algorithm. A risk score based on the type of surgery and patients characteristics determined the prophylactic treatment: high risk = droperidol 1.25 mg + ondansetron 4 mg; moderate risk = droperidol 1.25 mg. Cost of prophylactic and curative treatment was calculated according to the exact number of vials of antiemetics used. RESULTS: The use of the therapeutic algorithm leads to a reduction of PONV by a half (47.7% of 109 patients in 1999 vs. 24.5% of 102 patients in 2001) while twice more patients received a prophylactic treatment (32.1% vs. 75.5%). The number of patients needed to be treated (NNT) according to the algorithm to avoid PONV was 1.8 in this high-risk population. However, the relative risk to have PONV was only reduced by 66% with the combination of two antiemetics in 2001 and 22.5% patients still suffered from PONV despite the double prophylactic treatments. The relative risk of PONV without prophylactic treatment was spontaneously reduced by 25% between the two study periods (54% vs. 40%). After 15 months, the recommendations were followed in 43.1% of patients. A curative treatment was given in the same percentage of patients in 2001 and 1999 (63.4% vs. 68%), but followed the recommendations in fivefold more patients (47% vs. 9.1%). The cost of PONV treatment (prophylactic and curative) was increased by 3.5-fold between the two periods ( 55 for 109 patients vs. 190 for 102 patients). CONCLUSION: The use of a PONV therapeutic algorithm based on a scored risk was associated to a lower reduction of late PONV than already published in the literature while the cost was increased as expected. This suggests the efficacy of antiemetic prophylactic treatment might have been overestimated by large multicenter trials and is less in usual clinical conditions. Thus local evaluation of practice is required by performing quality insurance programs.

Adult↗
PubMed2004

[Inhalation induction].

OBJECTIVES: To clarify how pharmacokinetics explains the speed and quality of mask induction with sevoflurane alone or associated with adjuvants. To describe the various techniques to obtain adequate anaesthesia for laryngeal mask or tracheal tube insertion. To give the indications, contra-indications and complications of this technique. DATA SOURCES: Data were obtained from Medline and authors clinical experience. DATA SYNTHESIS: Inhalation induction in adults affords rapid loss of consciousness similar to the intravenous route if high concentrations of sevoflurane are delivered to the patient. Time of laryngeal mask or tracheal tube insertion is longer but may be reduced by adding N(2)O and/or a low opioid dose. The interest of benzodiazepine as premedication is not established but is highly probable when considering its potentiating effect on halogenated agents. Without any adjuvant, inhalation induction maintains spontaneous ventilation better than propofol. This justifies favouring this technique when difficult intubation is anticipated. This technique is associated to less or similar cardiovascular effects than intravenous propofol. However, some patients exhibit dramatic tachycardia and arterial pressure increase that should lead to caution in cardiovascular disabled patients. This sympathetic hyperactivity occurs with epileptiform EEG activity that was never associated with postanaesthesia mental dysfunction. In aged or cardiac patients, by reducing sevoflurane concentrations from 8% to 2% (or by 2% decreasing steps), the cardiovascular effect of this inhalation induction is better than propofol. This technique is contra-indicated in HMS susceptible patients and those suffering from a myopathy, or patients with intracranial hypertension, a full stomach or active gastro-oesophageal reflux. CONCLUSION: Inhalation induction in adults remains little used in common clinical practice. Technical improvement by adding opioids and education of anesthetists should increase the diffusion of this alternative method to intravenous induction of anaesthesia.

Anesthesia, Inhalation↗
PubMed2003

[Epidural analgesia in a pregnant woman with essential thrombocythaemia].

Epidural analgesia is often considered as risk of epidural haematoma in patient with essential thrombocythaemia because of the platelet disorder. In this observation, uncomplicated epidural analgesia was performed in a pregnant woman with asymptomatic essential thrombocythaemia, because the absence of bleeding symptoms was associated with normal thrombo-elastography and time of occlusion by PFA-100 suggesting normal platelet function. PFA-100 is a biological test evaluating platelet function in whole blood, which is easy and quick to perform. This case study suggests that this test might be useful in evaluating platelet function in obstetrics but must be validated before recommending its extensive use.

Adult↗
PubMed2003

[Postoperative nausea and vomiting: cost and advantage induced by a quality insurance programme. Part I: post anaesthesia care unit].

OBJECTIVES: To report the efficiency and direct cost induced by a quality insurance programme (QIP) aimed to reduce the incidence of post-operative nausea and vomiting (PONV) in the post-anaesthesia care unit. TYPE OF STUDY: Prospective and descriptive study. METHODS: The occurrence and treatment of PONV were prospectively recorded in the post-anaesthesia care unit in a standardised file before and following therapeutic recommendations made by volunteers component of a QIP. Prophylaxis was administered to patients according to a score of risks based on the type of surgery and patient characteristics. The real cost induced by this change of practice was evaluated according to pharmacists' accounts over 1 year. RESULTS: The QIP was associated to a 33.5% reduction of PONV relative risk and a 50% increase in prophylactic treatments. When this reduction of PONV was extrapolated to the total number of anaesthesia over 1 year, this QIP avoided PONV in 770 patients each year. The increase of cost reached 3572 as the cost by patient receiving a prophylactic treatment increased from 0.66 to 1. CONCLUSION: Despite an increase in the individual cost of PONV prophylaxis, the selection of patients by a "home" score of risk limits the indications of prophylactic treatment. Thus the increase in cost remains in acceptable ranges.

Adult↗
PubMed2003

Influence of propofol concentrations on multipulse transcranial motor evoked potentials.

BACKGROUND: Motor evoked potentials can be affected by propofol anaesthesia. We studied how increasing target concentrations of propofol altered transcranial motor evoked potentials (tcMEP) during scoliosis surgery. METHODS: Fifteen patients undergoing surgery for scoliosis were anaesthetized with remifentanil and propofol without nitrous oxide or neuromuscular blocking agents (BIS<60). tcMEP were elicited by transcranial electric multipulse stimulation of the motor cortex and recording of compound action potentials from the anterior tibialis muscle. tcMEP were obtained before surgery with propofol target values set from 4 to 8 mg litre(-1), and then during surgery. Arterial propofol concentrations were measured for each tcMEP recording. RESULTS: Before surgery, increasing propofol reduced tcMEP amplitude in a dose-dependent manner, with no effect on latency. During surgery, at equivalent propofol concentrations, tcMEP were not statistically different from those obtained before surgery. In all except one patient, tcMEP signals were present during the entire procedure. In this patient the loss of tcMEP was unfortunately related to an anterior spinal cord lesion, which was confirmed by a wake-up test. CONCLUSION: We found that, although propofol had a dose-dependent effect on tcMEP amplitude, anaesthesia could be maintained with remifentanil and propofol to allow recording and interpretation of tcMEP signals.

Adult↗
PubMed2002

The efficacy of chloroquine for the treatment of acute, uncomplicated, Plasmodium falciparum malaria in Laos.

To assess the local efficacy of chloroquine for the treatment of acute, uncomplicated, Plasmodium falciparum malaria, children and adults from Sekong province (an area of Laos with a low intensity of transmission) were tested in a 28-day, in-vivo study. Complete data were collected from 88 of the 102 subjects enrolled between October 1999 and September 2000. After genotypic analysis to distinguish recrudescing infections from re-infections, 35 (39.7%, with a 95% confidence interval of 29.5%-50.7%) of these 88 patients were considered treatment failures. These results seriously question the use of chloroquine as the first-line treatment for P. falciparum malaria in the study area.

Acute Disease↗
PubMed2001

Timely detection of meningococcal meningitis epidemics in Africa.

BACKGROUND: Epidemics of meningococcal disease in Africa are commonly detected too late to prevent many cases. We assessed weekly meningitis incidence as a tool to detect epidemics in time to implement mass vaccination. METHODS: Meningitis incidence for 41 subdistricts in Mali was determined from cases recorded in health centres (1989-98) and from surveillance data (1996-98). For incidence thresholds of 5 to 20 cases per 100000 inhabitants per week, we calculated sensitivity and specificity for detecting epidemics, and determined the time lapse between threshold and epidemic peak. FINDINGS: We recorded 9084 meningitis cases. Clinic-based weekly incidence of 5 and 10 cases per 100000 inhabitants detected all meningitis epidemics (sensitivity 100%, 95% CI 93-100), with median threshold-to-peak time of 5 and 3 weeks. Under-reporting reduced sensitivity: only surveillance thresholds of 5 or 7 cases per 100000 inhabitants per week detected all epidemics. Crossing the lower threshold before the 10th calendar week doubled epidemic risk relative to crossing it later (relative risk 2.1, 95% CI 1.4-3.2). At 10 cases per 100000 inhabitants per week, specificity for outbreak prediction was 88%, 95% CI 83-91). For populations under 30000, 3 to 5 cases in one or two weeks predicted epidemics with 85% to 97% specificity. INTERPRETATION: Low meningitis thresholds improve timely detection of epidemics. Ten cases per 100000 inhabitants per week in one area confirm epidemic activity in a region, with few false alarms. An alert threshold of 5 cases per 100000 inhabitants per week allows time to investigate, prepare for an epidemic, and initiate mass vaccination where appropriate. For populations under 30000, the alert threshold is two cases in a week. High quality surveillance is essential.

Disease Outbreaks↗
PubMed2001

Differential alterations in plasma colony-stimulating factor concentrations after coronary artery bypass graft surgery with extracorporeal circulation.

To determine whether colony-stimulating factor (CSF) might participate to the inflammatory response after cardiac surgery, plasma concentrations of granulocyte-CSF (G-CSF), macrophage-CSF (M-CSF) and GM-CSF were measured in 31 patients undergoing coronary artery bypass graft (CABG) surgery with extracorporeal circulation (ECC). Plasma G-CSF and M-CSF concentrations increased after weaning of ECC, reached maximum value at the sixth post-operative hour, and remained elevated at the 24th post-operative hour. In contrast, plasma GM-CSF levels did not change. Plasma M-CSF, G-CSF and GM-CSF values were not different whether patients developed post-operative complications or not. In conclusion, M-CSF and G-CSF are produced after CABG surgery despite the use of high aprotinin doses in hope to abrogate the inflammatory response. G-CSF and M-CSF might play a role in the inflammatory process often observed after CABG surgery.

Colony-Stimulating Factors↗
PubMed2001

Haemostatic disorders during liver transplantation.

Profound and complex coagulation disorders are encountered during liver transplantation. They include preoperative coagulation disorders related to the liver disease and haemostatic changes related to the procedure itself. They commonly lead to increased intraoperative bleeding, especially due to increased fibrinolysis, the contribution of which can be demonstrated by the relative efficacy of antifibrinolytics. Given the multifactorial nature of bleeding in liver transplantation, preoperative coagulation tests cannot predict blood loss even if some statistical relationship is occasionally found. Preoperative correction of coagulation defects has not been shown to be effective in reducing intraoperative bleeding. Throughout the procedure, a rapid and sensitive method for monitoring coagulation is necessary in order to guide the rational use of blood components and pharmacological agents. The usefulness of such a method to assist management of blood loss or blood component requirements is poorly documented and controversial.

Blood Coagulation Disorders↗
PubMed2001

Induction with propofol target-concentration infusion vs. 8% sevoflurane inhalation and alfentanil in hypertensive patients.

Haemodynamic parameters during an inhalation induction with 8% sevoflurane were compared with those obtained with a target-controlled infusion of propofol in 50 hypertensive patients in a prospective randomised study. Heart rate and arterial pressure were recorded continuously. End-tidal sevoflurane and nitrous oxide concentration, SpO2 and bispectral index (BIS) were also collected from the beginning of anaesthesia until 8 min after tracheal intubation. Patients either received 4 mg.l-1 target-concentration propofol or performed a vital capacity inhalation of 8% sevoflurane in a high flow of oxygen (8 l.min-1) supplemented with 50% nitrous oxide at loss of consciousness. As soon as BIS was < 60, 20 microg.kg-1 alfentanil and 0.6 mg.kg-1 rocuronium were injected and orotracheal intubation was then performed 1 min later. Thereafter, the end-tidal concentration of sevoflurane was reduced to 1.3 minimum alveolar concentration (MAC). Hypotension was defined as a 30% decrease in arterial pressure and was treated with repeated 3-mg boluses of ephedrine. When 12 mg ephedrine was unable to correct hypotension, the concentration of propofol was reduced by 1 mg.l-1 and that of sevoflurane by 0.5%. Hypotension occurred in 22 patients in the sevoflurane group and 21 in the propofol group, and hypertension occurred in two and three patients in each group, respectively. The maximal reduction in mean (SD) arterial pressure was similar in the sevoflurane (45 (4) mmHg) and propofol (41.3 (2.6) mmHg) groups, as were the ephedrine requirements (9.6 (1.1) vs. 9.1 (1.1) mg, sevoflurane vs. propofol, p > 0.05), the duration of hypotension (276 (37) vs. 292 (38) s, sevoflurane vs. propofol, p > 0.05), and the number of hypotensive episodes or anaesthetic changes and depth of anaesthesia. Nevertheless, heart rate was lower during the 8 min following tracheal intubation in the sevoflurane group. In both groups, the duration of hypotension was easily controlled either by ephedrine or by adjusting the anaesthetic concentrations. Overall, haemodynamic tolerance appears to be similar in the two techniques. Because hypotension occurred after alfentanil in most patients, this study questioned which is the best opioid dose, if any, to associate with propofol or sevoflurane for the induction in hypertensive patients.

Aged↗
PubMed2001

Morbidity in electroconvulsive therapy.

BACKGROUND AND OBJECTIVE: To assess retrospectively the complications and morbidity of electroconvulsive therapy. METHODS: Complications occurring in 75 patients during 612 electroconvulsive therapy procedures under propofol anaesthesia were reviewed by data analysis. RESULTS: At least one complication occurred in 51 patients (68%) during the course of their treatment. Among these complications, 12 were potentially life-threatening: one patient developed angina pectoris, another aspiration pneumopathy, there were two incidences of bronchospasm, three hypoxic episodes (SpO2 < 92% with FiO2=1) and five severe episodes of laryngospasm which caused hypoxia. Twenty-five patients (33%) were confused for more than 2 h after the electroconvulsive therapy. Confusion recurred in 10 patients (13%) after several sessions of electroconvulsive treatment. Six patients had a traumatic complication, with one requiring surgery. CONCLUSION: Our results, compared with other studies, suggest that electroconvulsive therapy is not a low-risk procedure, with a particularly high rate of respiratory complications that may have been previously overlooked. Therefore, ambulatory anaesthesia may not be appropriate on a regular basis for most of these patients.

Adult↗
PubMed2001

Platelet function during pregnancy: an evaluation using the PFA-100 analyser.

In clinical practice, the only tests of platelet function are bleeding time and platelet number. Bleeding time lacks sensitivity and specificity but the PFA-100, an in vitro analyser of platelet function may be of value. This study aimed to evaluate any correlation between platelet number and function using the PFA-100 in pregnant women. During a 21-month period, platelet function was evaluated in whole blood as part of the pre-anaesthetic coagulation testing screen with the PFA-100 using collagen and epinephrine (PFA-EPI) or ADP (PFA-ADP) as platelet agonists. Thrombocytopenia was defined as a platelet number less than 150 G litre(-1). The patients were divided into four groups: Group I (n=110) normal pregnancy; Group II (n=38) thrombocytopenia of pregnancy; Group III (n=13) women with pre-eclampsia without thrombocytopenia; Group IV (n=19) women with pre-eclampsia and thrombocytopenia. Results are expressed as mean (SD). Platelet count was not statistically different between Groups II and IV (111.1 (23.1) vs 99.5 (28.0) G litre(-1)). PFA-EPI was statistically increased in Group II (124.0 (26.3) s), Group III (128.3 (17.9) s), and Group IV (143.6 (47.7) s) compared with normal pregnant patients (114.6 (27.3) s, P<0.05, Mann-Whitney U-test). PFA-ADP was statistically increased only in Group II compared with normal pregnant patients (90.5 (18.9) vs 80.2 (11.2) s, P<0.05). PFA values were increased above normal laboratory values in (four of 38) Group II patients and (six of 19) Group IV patients but in no patients in Group III. PFA-ADP results were correlated with platelet count only in Group IV (r=-0.74, P=0.0003). The increased PFA values and the correlation between PFA-ADP and platelet number in hypertensive thrombocytopenic women confirms that platelet function may be decreased in such patients. In patients with pregnancy-induced thrombocytopenia, platelet function may be preserved when the platelet count is as low as 60 G litre(-1).

Adolescent↗
PubMed2000

Plasma interleukin-4, interleukin-10, and interleukin-13 concentrations and complications after coronary artery bypass graft surgery.

OBJECTIVES: To determine whether plasma interleukin (IL)-4, IL-10, and IL-13 concentrations are associated with complications after coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB). STUDY DESIGN: Prospective descriptive study. SETTING: University teaching hospital. PARTICIPANTS: Thirty-two patients during and 24 hours after CABG surgery. MEASUREMENTS AND MAIN RESULTS: Hemodynamic measurements and blood samples were obtained from 32 patients during and after surgery. Coagulation, pulmonary, and cardiovascular functions were specifically assessed during the first 24 hours postoperatively. Plasma IL-4 and IL-13 levels remained unchanged during CABG surgery. In contrast, plasma IL-10 concentrations increased by 117-fold in the immediate postoperative period and returned to pre-CPB values by 24 hours postoperatively. Plasma IL-10 levels were not different in patients with or without cardiovascular impairment, coagulation disorders, and lung injury. Plasma IL-10 levels did not correlate with the leukocyte count, the amount of catecholamines infused, or the duration of CPB. CONCLUSION: The present results suggest that the development of post-CABG surgery complications might be linked to an insufficient production of anti-inflammatory cytokines, such as IL-4, IL-10, or IL-13, which are unable to counteract the overproduction of inflammatory cytokines.

Aged↗