Liver-related deaths in HIV-infected patients between 1995 and 2010 in France: the Mortavic 2010 study in collaboration with the Agence Nationale de Recherche sur le SIDA (ANRS) EN 20 Mortalité 2010 survey.

OBJECTIVES: The aim of this study was to describe the proportion of liver-related diseases (LRDs) as a cause of death in HIV-infected patients in France and to compare the results with data from our five previous surveys. METHODS: In 2010, 24 clinical wards prospectively recorded all deaths occurring in around 26 000 HIV-infected patients who were regularly followed up. Results were compared with those of previous cross-sectional surveys conducted since 1995 using the same design. RESULTS: Among 230 reported deaths, 46 (20%) were related to AIDS and 30 (13%) to chronic liver diseases. Eighty per cent of patients who died from LRDs had chronic hepatitis C, 16.7% of them being coinfected with hepatitis B virus (HBV). Among patients who died from an LRD, excessive alcohol consumption was reported in 41%. At death, 80% of patients had undetectable HIV viral load and the median CD4 cell count was 349 cells/µL. The proportion of deaths and the mortality rate attributable to LRDs significantly increased between 1995 and 2005 from 1.5% to 16.7% and from 1.2‰ to 2.0‰, respectively, whereas they tended to decrease in 2010 to 13% and 1.1‰, respectively. Among liver-related causes of death, the proportion represented by hepatocellular carcinoma (HCC) dramatically increased from 5% in 1995 to 40% in 2010 (p = 0.019). CONCLUSIONS: The proportion of LRDs among causes of death in HIV-infected patients seems recently to have reached a plateau after a rapid increase during the decade 1995-2005. LRDs remain a leading cause of death in this population, mainly as a result of hepatitis C virus (HCV) coinfection, HCC representing almost half of liver-related causes of death.

Communication in healthcare: a narrative review of the literature and practical recommendations.

OBJECTIVES: Effective and efficient communication is crucial in healthcare. Written communication remains the most prevalent form of communication between specialised and primary care. We aimed at reviewing the literature on the quality of written communication, the impact of communication inefficiencies and recommendations to improve written communication in healthcare. DESIGN: Narrative literature review. METHODS: A search was carried out on the databases PubMed, Web of Science and The Cochrane Library by means of the (MeSH)terms 'communication', 'primary health care', 'correspondence', 'patient safety', 'patient handoff' and 'continuity of patient care'. Reviewers screened 4609 records and 462 full texts were checked according following inclusion criteria: (1) publication between January 1985 and March 2014, (2) availability as full text in English, (3) categorisation as original research, reviews, meta-analyses or letters to the editor. RESULTS: A total of 69 articles were included in this review. It was found that poor communication can lead to various negative outcomes: discontinuity of care, compromise of patient safety, patient dissatisfaction and inefficient use of valuable resources, both in unnecessary investigations and physician worktime as well as economic consequences. CONCLUSION: There is room for improvement of both content and timeliness of written communication. The delineation of ownership of the communication process should be clear. Peer review, process indicators and follow-up tools are required to measure the impact of quality improvement initiatives. Communication between caregivers should feature more prominently in graduate and postgraduate training, to become engraved as an essential skill and quality characteristic of each caregiver.

High-resolution tomography study of the porosity of three restorative resin composites.

OBJECTIVES: The aim of this study was to analyze the porosity of three photopolymerizable resin composites: one high-viscous resin composite (Filtek™ P60®, 3 M™ ESPE™), one moderate-viscosity resin composite (Grandio®, VOCO™), and one low-viscous resin composite (Filtek™ Supreme XTE®, 3 M™ ESPE™). MATERIALS AND METHODS: A total of 36 cylindrical samples with a height of 2 mm and a diameter of 2 mm were prepared using PTFE molds. Eighteen cylinders were prepared by two incremental applications of 1 mm into the molds, then polymerized (group 1). For the other 18 samples (group 2), the first increment was polymerized before the second addition was made. The average porosity percentage and the average porosity volume were evaluated by high-resolution tomography (Nanotom M® - Phoenix X-Ray(TM), Wunstorf, Germany). The impact of incremental applications in terms of porosity was also evaluated. RESULTS: Irrespective of the protocol used, the low viscous material presented an average porosity percentage and an average porosity volume significantly greater than those of the other materials. Incremental application (group 2 samples) led to an increase in the average porosity percentage and volume irrespective of the material compared to the group 1 samples. CONCLUSIONS: High-resolution tomography appeared to be a particularly suitable tool for studying the porosity of resin composites. The viscosity and the handling of these materials seemed to be influential factors on their porosity. CLINICAL RELEVANCE: The presence of porosities in dental resin composites remains an objective reality, especially with low-viscous resin composites. Since the intrinsic porosity of the materials can be neither controlled nor modified by the operator, rigorous and iterative clinical protocols still remain the best way to limit inclusion of porosities in the resin composites.

Body mass index and occupational accidents among health care workers in a large university hospital.

INTRODUCTION: Obesity is associated with a number of chronic diseases such as cardiovascular diseases and cancers. The association of obesity with occupational accidents has been suggested although the evidence is less convincing. The objective of the study is to analyse the relationship between BMI values and ergonomic accidents in a large University Hospital. METHODS: The relationship between body mass index (BMI) and the incidence of ergonomic occupational accidents over a period of 8 years was investigated in a cohort of employees of a large University Hospital, covering almost 27,000 person-years of observation. This relationship was stratified according to the variables age, gender, functional status within the organization and work schedule (part-time or full time). Height and weight were objectively measured, demographic data were obtained from the human resource department and the registration of ergonomic accidents was carried out by the safety and prevention department of the hospital. RESULTS: The number of ergonomic accidents, expressed as number/1000 person-years was higher for female employees compared to male employees, increased with age and markedly increased from functional class A (leading or expert function and higher educational level) to D (executive function in patient care and technical department). However, the incidence of ergonomic accidents accompanied by loss of working time was not significantly associated with BMI, independently of age and gender. In addition, the type of accident and the severity of the accidents expressed as the number of days absent from work were unrelated to BMI. CONCLUSION: No independent relationship between BMI and the incidence of ergonomic accidents could be identified in our cohort. Tailoring working conditions to individual BMI levels is not recommended.

[Use of the tourniquet test in diagnosing dengue-like syndrome]. / Intérêt du signe du lacet devant un syndrome Dengue-like.

A 26-year-old nurse presented with a three-day history of sudden onset of pyrexia of 39 °C, malaise, and a patchy maculopapular rash, after returning from a monthlong work in Senegal. A tourniquet was applied to help locate the vein for diagnostic blood sampling. After the procedure, a petechial rash erupted with a demarcation line below the level of the tourniquet. A diagnostic test for dengue fever was performed and confirmed by the polymerase chain reaction (PCR) to be positive for serotype DEN-1. The tourniquet test is performed by inflating a blood pressure cuff tied on the upper arm to a point midway between systolic and diastolic blood pressure for five minutes. The test is considered positive when there are 20 or more petechiae per square inch (6.25 cm(2)) on the forearm, and is one of several clinical parameters considered by the World Health Organization to be important in the diagnosis of dengue fever.

[Drug resistance testing of Mycobacterium tuberculosis isolates from sputum in Chad]. / Étude de la résistance de Mycobacterium tuberculosis chez les patients bacillifères au Tchad.

Culture and resistance testing of Mycobacterium tuberculosis are not regularly performed in Chad. Sputa were obtained from three different categories of hospitals (district, regional and national) in Chad. All examined sputa were smear-positive and were investigated by culture and drug resistance testing for first-line antituberculosis drugs. From 232 sputa positive for acid-fast bacilli, 135 isolates of M. tuberculosis from different patients (46 women, 89 men, mean age 34 years) were analyzed. All the patients except one corresponded to new cases of tuberculosis. In total, 27 out of 135 isolates (20%) were resistant to at least one major antituberculosis drug. Resistance to isoniazid was the most frequent resistance observed, with 18 isolates (13%) presenting at least this resistance. Three isolates (2.2%) were resistant to isoniazid and rifampicin (multidrug resistance MDR) including one isolate being concomitantly resistant to streptomycin and ethambutol. The resistance rate differed in relation to the category of the hospital; the most important resistance rate was observed in regional hospitals (33%), while it was 16% and 14% in the national and district hospitals, respectively. HIV serology was performed in 81 patients, among whom 20 (25%) were positive. This is the first study that shows that drug resistance of M. tuberculosis is present in Chad. Besides single drug-resistant isolates, multidrug-resistant strains of M. tuberculosis could also be identified. This result highlights the urgency of initiating actions to detect drug resistance and limit the spread of drug-resistant strains.

Coasting: worth the effort?

A new anesthesia machine incorporates a "coasting mode", but the extent to which a coasting technique can maintain anesthesia at the end of a procedure under optimal conditions (closed circuit anesthesia) remains unknown. Sixty-nine patients undergoing peripheral or abdominal surgery were assigned to 1 of 9 groups, depending on when desflurane coasting (in O2/air) was started (after 4, 9, 16, 25, 36, 49, 64, 81, or 100 min). The end-expired desflurane concentration was maintained at 4.5% in O2/air prior to coasting with a conventional anesthesia machine. After initiating coasting (using a closed-circuit technique), we examined when the end-expired desflurane concentration reached 70, 60, 50, and 40% of its value during maintenance (= 30, 40, 50 and 60% decrement times, respectively). Decrement times increased with increasing duration of anesthesia, and varied widely. After 64 min of maintenance anesthesia, the end-expired desflurane concentration remained at or above 70, 60, 50, and 40% of its maintenance value during 10.3 +/- 2.3, 16.0 +/- 3.5, 25.0 +/- 5.9, and 45.4 +/- 19.3 min, respectively (average +/- standard deviation). Coasting can briefly maintain anesthesia towards the end of a procedure. While savings with an automated coasting mode are likely to be modest per patient, they may become substantial when multiplied by the number of procedures per day per operating room with no increase in the clinical workload of the anesthesia provider.

Influence of steep Trendelenburg position and CO(2) pneumoperitoneum on cardiovascular, cerebrovascular, and respiratory homeostasis during robotic prostatectomy.

BACKGROUND: The steep (40 degrees ) Trendelenburg position optimizes surgical exposure during robotic prostatectomy. The goal of the current study was to investigate the combined effect of this position and CO(2) pneumoperitoneum on cardiovascular, cerebrovascular, and respiratory homeostasis during these procedures. METHODS: Physiological data were recorded during the whole surgical procedure in 31 consecutive patients who underwent robotic endoscopic radical prostatectomy under general anaesthesia. Heart rate, mean arterial pressure, central venous pressure, Sp(o(2)), Pe'(co(2)), P(Plat), tidal volume, compliance, and minute ventilation were monitored and recorded. Arterial samples were obtained to determine the arterial-to-end-tidal CO(2) tension gradient. Continuous regional cerebral tissue oxygen saturation (Sct(o(2))) was determined by near-infrared spectroscopy. RESULTS: Although patients were in the Trendelenburg position, all variables investigated remained within a clinically acceptable range. Cerebral perfusion pressure (CPP) decreased from 77 mm Hg at baseline to 71 mm Hg (P=0.07), and Sct(o(2)) increased from 70% to 73% (P<0.001). Pe'(co(2)) increased from 4.12 to 4.79 kPa (P<0.001) and the arterial-to-Pe'(co(2)) tension difference increased from 1.06 kPa in the normal position to a maximum of 1.41 kPa (P<0.001) after 2 h in the Trendelenburg position. CONCLUSIONS: The combination of the prolonged steep Trendelenburg position and CO(2) pneumoperitoneum was well tolerated. Haemodynamic and pulmonary variables remained within safe limits. Regional cerebral oxygenation was well preserved and CPP remained within the limits between which cerebral blood flow is usually considered to be maintained by cerebral autoregulation.

Influence of an increased intracranial pressure on cerebral and systemic haemodynamics during endoscopic neurosurgery: an animal model.

BACKGROUND: During endoscopic neurosurgery, direct mechanical stimulation of the brain by the endoscope and increased intracranial pressure (ICP) caused by the continuous rinsing can induce potentially lethal haemodynamic reflexes, brain ischaemia, and excessive fluid resorption. METHODS: In a newly presented rat model of endoscopic neurosurgery, stereotactic access to the cerebrospinal fluid was secured and the ICP was increased by controlled infusion until complete suppression of the cerebral perfusion pressure (CPP). The haematocrit (Hct) level was determined before and after the procedure. During the whole procedure, invasive arterial pressure, ICP, and heart rate were continuously recorded and evaluated in a subsequent offline analysis. After the procedure, the animals were allowed to recover and 7 days later they were killed for histological examination. RESULTS: Suppression of the CPP resulted in a severe hypertension combined with tachycardia or mild bradycardia. The Hct decreased from 41 to 35 over the minutes of CPP suppression. After cessation of the infusion, the ICP decreased to 37% of the plateau pressure within 2.5 s. In the first few minutes after restoration of normal ICP, five animals died because of pulmonary oedema. CONCLUSIONS: Upon complete suppression of the CPP, an obvious hypertension developed, often together with tachycardia, but no severe bradycardia. At high ICP levels, we observed an important translocation of irrigation fluid to the vascular space. Fatality was not caused by ischaemia or arrhythmia but due to pulmonary oedema.

[Day hospital in internal medicine: A chance for ambulatory care]. / L'hôpital de jour en médecine interne : un atout pour le virage ambulatoire.

INTRODUCTION: Internal medicine is an in-hospital speciality. Along with its expertise in rare diseases, it shares with general medicine the global care of patients but its place in the ambulatory shift has yet to be defined. The objective of our work was to evaluate the benefits of an internal medicine day-hospital devoted to general medicine. METHODS: Named "Centre Vi'TAL" to underline the link between the city and the hospital, this novel activity was implemented in order to respond quickly to general practitioners having difficulties to synthesize their complex patients or facing diagnostic or therapeutic problems. Using preferentially email for communication, the general practitioners can contact an internist who is committed to respond on the same day and take over the patient within 7 days if day-hospital is appropriate for his condition. The other patients are directed either to the emergency department, consultation or full hospitalization. RESULTS: In 14 months, the center has received 213 (144 women, 69 men) patients, mean age 53.6, addressed by 88 general practitioners for 282 day-hospital sessions. Requests included problem diagnoses (n=105), synthesis reviews for complex patients (n=65), and treatment (n=43). CONCLUSION: In the ambulatory shift advocated by the authorities, this experience shows that internal medicine should engage in the recognition of day-hospital as a place for diagnosis and synthesis reviews connected with the city while leaving the general practitioners coordinator of their patient care. This activity of synthesis in day-hospital is useful for the patients and efficient for our healthcare system.

Comparison of volume-controlled and pressure-controlled ventilation during laparoscopic gastric banding in morbidly obese patients.

BACKGROUND: There are no guidelines on ventilation modes in morbidly obese patients. We investigated the effects of volume-controlled (VCV) and pressure-controlled ventilation (PCV) on gas exchange, respiratory mechanics, and cardiovascular responses in laparoscopic gastric banding procedures. METHODS: After Institutional Review Board approval, 24 adult consenting patients scheduled for laparoscopic gastric banding were studied. Anesthesia was standardized using remifentanil, propofol, rocuronium, and sevoflurane. All patients started with VCV with a tidal volume of 10 ml kg(-1) ideal body weight, respiratory rate adjusted to obtain an end-tidal carbon dioxide of 35-40 mmHg, positive end-expiratory pressure of 5 cmH2O, an inspiratory pause of 10% and an inspiratory/expiratory ratio of 1:2. Fifteen minutes after pneumoperitoneum, the patients were randomly allocated to two groups. In Group VCV (n = 12), ventilation was with the same parameters. In Group PCV (n = 12), the airway pressure was set to provide a tidal volume of 10 ml kg(-1) ideal body weight without exceeding 35 cm H2O. Respiratory rate was adjusted to keep an end-tidal carbon dioxide of 35-40 mmHg. Arterial blood samples were drawn after surgical positioning and 15 min after allocation. Analysis of variance (ANOVA) was used for statistical analysis. RESULTS: With constant minute ventilation, VCV generates equal airway pressures and cardiovascular effects with a lower PaCO2 as compared to PCV (42.5 (5.2) mmHg versus 48.9 (4.3) mmHg, p < 0.01 ANOVA). Arterial oxygenation remained unchanged. CONCLUSIONS: VCV and PCV appear to be an equally suited ventilatory technique for laparoscopic procedures in morbidly obese patients. Carbon dioxide elimination is more efficient when using VCV.

Matching the peripheral intravenous catheter to the individual patient.

Up to eighty percent of all patients admitted to hospital worldwide will receive a peripheral IV and this procedure is now considered indispensable to human health. However, despite its global use, the choice of catheter is not always governed by clear and universal guidelines. After reviewing the few best-practice recommendations which exist, we propose a patient--and therapy--driven matrix for deciding on the gauge and length of peripheral catheter for the individual patient. This matrix takes patient age, clinical stability, current state of veins, therapy duration and the nature of the medication to be delivered into consideration. Use of such a matrix will not deliver a formulaic answer but will orient choices along logical, evidence-based lines. This approach will be an advance on the all-too-common reliance on habit and tradition in the choice of peripheral IV catheter.

Filler Content, Surface Microhardness, and Rheological Properties of Various Flowable Resin Composites.

OBJECTIVES: The objectives of this study were to determine the filler content, the surface microhardness (at baseline and after immersion in water for 2 years), and the rheological properties of various flowable resin composites. METHODS: Three flowable resin composites (Grandioso Heavy Flow [GHF], Grandio Flow [GRF], Filtek Supreme XTE Flow [XTE]), one pit and fissure sealant resin composite (ClinPro [CLI]), and three experimental flowable resin composites with the same matrix and a variable filler content (EXPA, EXPB, EXPC) were tested. The filler content was determined by calcination. The Vickers surface microhardness was determined after polymerization and then after immersion in distilled water at 37°C for 7, 60, 180, 360, and 720 days. The rheological measurements were performed using a dynamic shear rheometer. RESULTS: The determined filler contents differed from the manufacturers' data for all the materials. The materials with the highest filler content presented the highest microhardness, but filler content did not appear to be the only influencing parameter. With respect to the values recorded after photopolymerization, the values were maintained or increased after 720 days compared with the initial microhardness values, except for GHF. For the values measured after immersion for 7 days, an increase in microhardness was observed for all the materials over time. All the materials were non-Newtonian, with shear-thinning behavior. At all the shear speeds, GRF presented a lower viscosity to GHF and XTE. CONCLUSIONS: GRF presented a low viscosity before photopolymerization, associated with high filler content, thereby providing a good compromise between spreadability and mechanical properties after photopolymerization.

[Feasibility of cervical smear in HIV-positive women living in Chad]. / Faisabilité du frottis cervico-utérin chez les femmes séropositives pour le VIH vivant au Tchad.

Cervical cancer is the leading cause of cancerrelated death in Sub-Saharan African women. HIV-infected women are at increased risk for cervical intraepithelial lesions and invasive cervical cancer. WHO guidelines for screening and treatment of precancerous cervical lesions are regularly actualized. There are no data on cervical squamous intraepithelial lesions in Chad. Between August 2013 and May 2015, screening for cervical squamous intraepithelial lesions was proposed to HIV-infected women living in Moundou (Chad). Cytology examination was performed after with Papanicolaou coloration. Three hundred and eleven HIV-seropositive women accepted the screening without refusal. Mean age of the patients was 38 years (95% Confidence Interval: 37.7-39.9). The women declared a mean of 4.1 pregnancies (range: 0-12). The patients had been followed-up for their seropositivity for 8 years (range: 0-25). All were on highly active antiretroviral therapy (HAART). Of the patients whose results were known (N = 231), 98% had a CD4 lymphocyte nadir count less than 350/mm(3). Cytological results were as follows: normal smear (N = 59; 19%), inflammatory or hemorrhagic smear (N = 139; 44%), low grade squamous intraepithelial lesion (N = 58; 19%), high grade squamous intraepithelial lesion (N = 28; 9%), epidermoid carcinoma (N = 13; 4%), and uninterpretable smear (N = 14; 5%). The inflammatory lesions were due to cervicitis (N = 54), vaginosis (N = 22), and trichomonas infection (N = 3). The patients' age, CD4 lymphocyte nadir count, and CD4 count at the time of the cervical smear were not different according to the cytological results. Only five patients had a cone biopsy. Three patients deceased during the study of whom two from a gynaecological cancer diagnosed too late. The screening of dysplasia and cervical cancer in HIV-seropositive women is possible in Chad. In our study, 13% of the women had highgrade dysplasia or carcinoma needing curative care. We also showed that simple cytology did not permit the interpretation of half of the smears. The performance of cervical smear would have increased if it had been preceded by the visualization of the cervix with coloration.

[Choice of initial regimen for antiretroviral-naïve HIV patients: Analysis of motivation]. / Analyse des motivations du choix des antirétroviraux (ARV) prescrits chez des patients infectés par le VIH (PVVIH) naïfs.

OBJECTIVE: Several therapeutic combination antiretroviral therapy regimen are available for initial treatment in naïve HIV infected patients. The choice of a particular regimen remains often subjective. The aim of this study was to determine factors associated with the choice of molecules in initial ARV prescriptions. METHODS: From 01/01 to 30/10/2014, every initial cART prescription was analyzed regarding patients and physicians characteristics. Then, prescriptions were evaluated by an independent committee of ART prescribers. RESULTS: One hundred and thirty two consecutive initial prescriptions by 34 physicians of 11 medical centers were included: 71 M, migrants: 57 %, MSM: 21 %, CD4<200/mm3: 26 %, HIV RNA>100 000 cp/mL (33 %). cART regimen were: NRTI/PI (43 %), NRTI/NNRTI (29.5 %), NRTI/integrase inhibitor (23 %). 75 % of initial cART regimen were consistent with expert guidelines recommendations. The choice of initial cART was not influenced by the type of HIV contamination risk group, patient's geographic origin, CD4 levels. In contrast, working or not (P=0.007), pregnancy wish (P=0.07), pregnancy (P=0.001), HIV RNA levels (P=0.02) and HIV primary infection (P=0.049) influenced the initial choice. Neither physician's age, nor physician's experience influenced this choice. The prescription's non accordance to 2013 French guidelines was mainly related to integrase inhibitor utilisation (P= 0.0001). CONCLUSION: Overall, cART initial choice is mostly consistent with guidelines. Primary HIV infection, procreation features and high viral load are the main factors influencing this choice. New regimen with better tolerability is prescribed even if it is not yet included in the guidelines.

The focal adhesion targeting sequence is the major inhibitory moiety of Fak-related non-kinase.

Focal adhesion kinase (FAK) plays an important role in integrin-mediated signal transduction pathways and its C-terminal noncatalytic domain Fak-related non-kinase (FRNK), which is autonomously expressed, acts as an inhibitor of FAK. A model has been proposed where FAK and FRNK compete for an essential common binding protein. A FRNK variant in which the direct interaction with v-Crk-associated tyrosine kinase substrate (CAS) was disturbed by point mutations still functioned as an inhibitor of FAK, suggesting that FRNK is unlikely to inhibit FAK by sequestering CAS. Deletion variants of FRNK within the region N-terminal to the focal adhesion targeting (FAT) sequence were still able to inhibit FAK function, indicating that this region is dispensable for the inhibitory effect of FRNK. Overexpression of a green fluorescent protein (GFP) fusion protein containing the FAT sequence delayed cell spreading and reduced FAK tyrosine phosphorylation. This indicates that the FAT sequence is the major inhibitory moiety within FRNK.

[Consequences of replacing abacavir for indinavir in successful antiretroviral treatment of a patient with HIV infection]. / Conséquences de la substitution de l'indinavir par l'abacavir chez un patient infecté par le VIH en succès thérapeutique.

INTRODUCTION: Simplification of combined antiretroviral therapy in HIV-infected patients is possible, but virological success can be compromised by the development or emergence of resistant viruses. CASE: Worsening renal functioning in a patient under successful combination antiretroviral therapy resulted led to the replacement of indinavir by abacavir. Eight weeks later, his viral load rose and he developed a mutant virus resistant to all the nucleoside analogs. DISCUSSION: Our case report illustrates the danger of streamlining combined antiretroviral therapy composed only of nucleoside analogs in patients already successfully treated with nucleoside analogs, by exposing them to the risk of the emergence of a mutant virus.

Cardiopulmonary bypass and the pharmacokinetics of drugs. An update.

Cardiopulmonary bypass is accompanied by profound changes in the organism that may alter the pharmacokinetics of drugs. Drug distribution can be altered, for example, by changes in blood flow and by haemodilution, with a decrease in protein binding; a decrease in the elimination of some drugs can be caused by impairment of renal or hepatic clearance, due, for example, to lowered perfusion and hypothermia. The subject was reviewed in the Journal in 1982, and the emphasis of the present review is on new data related to specific drugs. The following substances are dealt with: benzodiazepines, cephalosporins, digitalis glycosides, general anaesthetics, glyceryl trinitrate (nitroglycerin), lignocaine (lidocaine), muscle relaxants, nitroprusside, opiates, papaverine and propranolol. For many of these substances an abrupt decrease has been observed in serum concentration upon initiation of bypass, which is explained by haemodilution and an increase in distribution due to decreased protein binding. For nitrates and some opiates, adsorption to the bypass apparatus was shown to be important. The gradual increase in serum concentrations seen during cardiopulmonary bypass with some drugs after the initial fall is usually explained by redistribution of the drug and/or decrease in its elimination. The same phenomena are thought to explain why in the post-bypass period a concentration increase occurs, or at least a slower decrease than expected. However, drug elimination has been directly measured in only a few studies. The short duration of the bypass procedure and the continuous changes during the process hamper a rigorous pharmacokinetic evaluation. Studies allowing more precise understanding of the mechanisms underlying the observed concentration changes are needed, but are difficult to design. Similarly, more data are awaited on the pharmacodynamic and clinical consequences of the concentration changes.

A paravenous approach for the saphenous nerve block.

BACKGROUND AND OBJECTIVES: This study assesses a paravenous approach for saphenous nerve block at approximately the level of the tibial tuberosity, and compares it with the conventional technique of blind subcutaneous infiltration between the tibial tuberosity and the gastrocnemius muscle. METHODS: In dissections of 5 cadavers, the saphenous nerve was found very close to the saphenous vein bilaterally. Subsequently, in 20 volunteers, a bilateral saphenous nerve block was performed with 5 mL mepivacaine on each side. Randomly assigned, the block was performed by blind subcutaneous injection using a 23-gauge needle of 2.5 cm on one side and by a paravenous subcutaneous approach on the other. RESULTS: The paravenous approach produced a saphenous nerve block in all 20 volunteers whereas the blind subcutaneous approach was successful in only 6 (33%) (P <.05). Seven volunteers had a painless minor hematoma at the paravenous site and 2 had a hematoma at the classical site. CONCLUSION: The saphenous nerve can be blocked effectively by a paravenous approach using only 5 mL of local anesthetic solution. This approach is advantageous because of its easily identifiable landmark.