Tissue Doppler imaging estimation of pulmonary artery occlusion pressure in ICU patients

Objective Earlier reports suggested that transthoracic (TTE) determination of the ratio of mitral inflow E wave velocity to early diastolic mitral annulus velocity (E/E) measured by tissue Doppler imaging (TDI) closely approximates PAOP in cardiac patients. However, the value of E/E for PAOP assessment in ICU patients has not been evaluated. This study assessed whether the E/E ratio provides an accurate estimation of pulmonary artery occlusion pressure (PAOP) in mechanically ventilated ICU patients.Design and setting Prospective, open, clinical study in the ICU of a university hospital.Patients Twenty-three consecutive mechanically ventilated patients.Interventions Volume expansion in 14 patients.Measurements and results Doppler TTE or TEE mitral inflow and TDI mitral annulus velocities were determined and compared with PAOP measured using a Swan-Ganz catheter. Of all the Doppler variables studied the best correlations were observed between PAOP and the lateral (r=0.84) and medial (r=0.76) annulus E/E ratio and remained highly significant when the analysis was restricted to TEE (r=0.91 and 0.86) or TTE (r=0.73 and 0.61). The sensitivities and specificities of estimating PAOP at 15 mmHg or higher were, respectively, 86% and 81% for lateral E/E above 7.5 and 76% and 80% for medial E/E above 9. PAOP changes after volume expansion (700±230 ml) were limited and accurately assessed by repeated E/E determinations.Conclusions In mechanically ventilated ICU patients TTE or TEE E/E determinations using TDI closely approximate PAOP.     

Alveolar pressure during high-frequency jet ventilation

We studied the influence of ventilatory frequency (1–5 Hz), tidal volume, lung volume and body position on the end-expiratory alveolar-to-tracheal pressure difference during high-frequency jet ventilation (HFJV) in Yorkshire piglets. The animals were anesthetized and paralysed. Alveolar pressure was estimated with the clamp off method, which was performed by a computer controlled ventilator and which had been extensively tested on its feasibility. The alveolar-to-tracheal pressure difference increased with increasing frequency and with increasing tidal volume, the common determinant appearing to be the mean expiratory flow. The effects in prone and in supine position were similar. Increasing thoracic volume decreased the alveolar-to-tracheal pressure difference indicating a dependence of this pressure difference on airway resistance. We concluded that the main factors determining the alveolar-to-tracheal pressure difference (P) during HFJV are expiratory flow (V_E) and airway resistance (R), PV_E×R.     

Urinary excretion of cyclic AMP in bacterial infections

Summary Urinary cyclic AMP excretion was found to be increased in patients with severe bacterial infections and normal renal function. The observed changes appeared due to a combination of an increased filtered load plus augmented nephrogenous production in some patients; while in others, only an increase in the apparent nephrogenous production of cAMP could be found to account for the elevation in the total urinary excretion. Since total serum calcium was found to be low in most of these patients, increased PTH secretion to reduce urinary excretion of calcium may have been responsible for an increase in renal parenchymal production, and subsequent excretion of cyclic AMP. Although speculative, this theory is tenable in that ionized hypocalcemia exists in septic patients.Abbreviations cAMP cyclic 3, 5-adenosine monophosphate - PTH parathormone - ADH andidiuretic hormone - GFR glomerular filtration rate     

Temporal heterogeneity of endothelium-dependent and -independent dilatation of brachial artery in patients with coronary artery disease

Background: Endothelial function is routinely assessed with high frequency ultrasound of the brachial artery. Fixed time points (1 post-occlusion and 3 post-nitrate) are commonly used to assess dynamic changes in brachial artery diameter. The underlying assumption is the lack of variability in temporal response to both endothelium-dependent and -independent stimuli. Objective: To evaluate the temporal course of endothelium-dependent (flow-mediated) and endothelium-independent (nitrate-induced) vasodilation of the brachial artery in patients with coronary artery disease (CAD) using high resolution (10 MHz) ultrasound. Methods: Thirty-seven patients with angiographically assessed CAD were prospectively enrolled in the study. End-diastolic, two-dimensional, long axis ultrasonographic images of the brachial artery were digitally stored on-line every 10 s, from baseline up to 4 during flow-mediated and up to 7 during 300 g sublingual nitrate-induced vasodilation of the brachial artery. Results: The mean percent endothelium-dependent flow-mediated maximal dilation (FMD) measured at 60 s was lower than the mean peak FMD (4.8 ± 4.1 vs. 6.6 ± 5.2%; p < 0.01). By 60 s only eight patients (35%) reached their maximum FMD response. The mean time to reach peak FMD was 87 ± 33 s. The mean time for the peak nitrate dilation was 291 ± 73 s. The peak nitrate-induced percent dilation was higher than that measured at 3 min (12.2 ± 6.7 vs. 5.4 ± 4.5%; p < 0.001). By 190 s, only four patients (11%) reached their maximum nitrate response. Conclusion: The routinely used measurement time points for evaluation of FMD and endothelium-independent vasodilation may not be adequate to detect the peak responses of individual patients with CAD.     

Apports à la botanique et culture du ginseng

Résumé: Létude des principes actifs des différents ginsengs, aux vertus thérapeutiques connues, tant recherchées, nous ramène à létude du sol, aux moyens de culture, au climat, mais aussi à la forme des racines. De certaines régions de la Chine, son pays dorigine, en passant par la Sibérie, le Canada puis la France autant de noms que dappellations, autant de racines découvertes au fil du temps, qui rendent difficiles la différenciation entre les vrais ou faux ginsengs. Tous ces éléments donnent à la plante ses principes actifs qui viennent en aide au terrain de lindividu dont Claude Bernard rappelait: «Le microbe nest rien, cest le terrain qui est tout.» Cette approche est le seul moyen de revenir à cette médecine globale quest la phytothérapie.* Communication présentée lors de la 12^e Journée universitaire de lAMPP, septembre 2003: Ginseng et autres plantes adaptogènes.     

Enquête ethnobotanique: screening chimique et efficacité thérapeutique de quelques plantes utilisées contre le paludisme en médecine traditionnelle à Brazzaville

Résumé: Les effets antipaludiques des extraits de trois plantes de la pharmacopée traditionnelle congolaise, Cassia siamea, Cassia spectabilis, Tetracera alnifolia (sélectionnées à partir dune enquête ethnobotanique), ont été étudiés chez des malades (20 pour chaque extrait) présentant une goutte épaisse positive et une hyperthermie. Les grandes familles chimiques de lextrait le plus efficace ont été recherchées en utilisant les méthodes phytochimiques classiques. Lextrait aqueux de Cassia siamea a présenté leffet antipaludique le plus important (sur la parasitémie et lhyperthermie); cette intéressante activité du Cassia siamea pourrait sexpliquer par la présence des alcaloïdes et des quinones.     

Assessment of Pulmonary Mechanics in Mechanical Ventilation: Effects of Imprecise Breath Detection, Phase Shift and Noise

Objective. In mechanical ventilation, the assessment of pulmonary mechanics, mainly of total compliance (Crs), total resistance (Rrs), and intrinsic positive end-expiratory pressure (PEEPint), is clinically important. By using airway pressure (Paw) and flow (Vaw), the least squares fit (LSF) method allows the continuous calculation of these parameters. The objective of this work was to study the influence of imprecise breath detection, phase shift between airway pressure and flow signals, and noise on the determination of Crs, Rrs, and PEEPint. Methods. Paw and Vaw were mathematically simulated as well as recorded in mechanically ventilated patients. Crs, Rrs, and PEEPint were computed off-line using the LSF method. The boundaries of the breath data window and the phase relationship between Paw and Vaw signals were manipulated and noise was superimposed. Results. Both simulated and patient data gave similar results. Crs and Rrs were not sensitive to imprecise breath detection. If the first portion of the breath was missed, the mean relative error on PEEPint was 20% or 53% when the exact beginning of inspiration was missed by 0.1 or 0.3 sec, respectively. Paw lag of 66 ms with respect to Vaw yielded a relative error of –15 ± 4% (mean ± SD) for Rrs, –5 ± 2% for Crs, and +13 ± 16% for PEEPint. Paw lead of 66 ms with respect to Vaw yielded a relative error of +5 ± 4% for Rrs, +7 ± 3% for Crs, and +14 ± 18% for PEEPint. Noise had very little impact on the accuracy of Crs, Rrs, and PEEPint. Conclusions. We conclude that the LSF method allows the assessment of Crs, Rrs, and PEEPint even with high levels of noise in patients with normal lungs provided that Paw and Vaw signals are precisely synchronised and a reliable breath detection algorithm is used.     

Serum MIP-1α and IL-8 in septic patients

We studied blood MIP-1 and IL-8 in 38 septic patients and 5 healthy volunteers. Both chemokines were undetectable in the healthy volunteers. In sepsis, serum MIP-1 was detected in 45% of the patients and IL-8 in 84%. The levels of MIP-1, but not of IL-8, correlated with CRP, IL-6 and TNF levels. Complication, including various organ failures and mortality, showed no correlation with serum MIP-1 levels. In contrast, we found increased levels of serum IL-8 in septic patients with disseminated intravascular coagulation, central nervous system (CNS) dysfunction or renal failure, and the mortality rate was higher in the IL-8-detectable group than in the IL-8 undetectable group (50% vs 0%,p<0.05). In conclusion, the production of both MIP-1 and IL-8 was increased and initially detectable levels of circulating IL-8 predicted high mortality in sepsis.Objective To determine the significance of the C-C chemokine MIP-1 and the C-X-C chemokine IL-8 in sepsis.Design Prospective study.Setting Clinical investigation, emergency department and general intensive care unit of university hospital.Patients and participants 38 septic patients and 5 healthy volunteers were studied. Sepsis was diagnosed following the criteria formulated by ACCP/SCCM.Interventions 10–20 ml of blood was drawn from each patient at the time of initial diagnosis of sepsis.Measurements and results MIP-1 and IL-8 were determined by sand-wich ELISA. Both chemokines were undetectable in the healthy volunteers. In sepsis, serum MIP-1 was detected in 45% of the patients and IL-8 was detected in 84%. The levels of MIP-1, but not of IL-8, correlated with CRP, IL-6 and TNF levels. Complications, including various organ failures and mortality, showed no correlation with serum MIP-1 levels. In contrast, we found increased levels of serum IL-8 in patients with disseminated intravascular coagulation (DIC) (p<0.05), central nervous system (CNS) dysfunction (p<0.05), renal failure (p<0.01) and the mortality rates were higher in the IL-8 detectable group than in the IL-8 undetectable group (50% vs 0%,p<0.05).Conclusions The production of MIP-1 and IL-8 was increased in sepsis. Furthermore, an initially detectable level of circulating IL-8, but not MIP-1, predicted a high mortality in sepsis diagnosed according to the ACCP/SCCM criteria.This study was supported in part by a Grant-in-Aid from the Japanese Ministry of Education, Science and Culture, the Waxman Institute Research Fund and the Keio Fukuzawa Fund     

Stroke output variations calculated by esophageal Doppler is a reliable predictor of fluid response

Objective Esophageal Doppler allows continuous monitoring of stroke volume index (SVI) and corrected flow time (FTc). We hypothesized that variations in stroke output index SOI (SVI/FTc) during volume expansion can predict the hemodynamic response to subsequent fluid loading better than the static values.Design and setting Prospective study in the intensive care unit of a university hospital.Patients Fifty-one patients with circulatory failure were monitored by esophageal Doppler.Interventions Patients who responded to a first fluid challenge received a second one. Patients who responded to both were classified as responders-responders, and those who did not respond to the second as responders-nonresponders. In these two groups we compared SVI, FTc, and SOI during each fluid challenge and also static values at the end of each fluid challenge.Measurements and results After the first fluid challenge SOI and SVI were significantly higher in patients who responded to subsequent volume expansion than in patients who no longer responded. ROC curves showed that SOI was a better predictor of fluid responsiveness than SVI. During volume expansion a SOI value of 11% discriminated between responders and nonresponders to subsequent volume expansion with a sensitivity of 91% and a specificity of 97%. There was no significant difference between the two groups for FTc value at the end of first fluid challenge.Conclusions Analysis of SOI during fluid challenge predicts response to subsequent fluid challenge and FTc is not a reliable indicator of cardiac preload.     

Pulse pressure variations to predict fluid responsiveness: influence of tidal volume

Objective To evaluate the influence of tidal volume on the capacity of pulse pressure variation (PP) to predict fluid responsiveness.Design Prospective interventional study.Setting A 31-bed university hospital medico-surgical ICU.Patients and participants Sixty mechanically ventilated critically ill patients requiring fluid challenge, separated according to their tidal volume.Intervention Fluid challenge with either 1,000 ml crystalloids or 500 ml colloids.Measurements and results Complete hemodynamic measurements including PP were obtained before and after fluid challenge. Tidal volume was lower than 7 ml/kg in 26 patients, between 7–8 ml/kg in 9 patients, and greater than 8 ml/kg in 27 patients. ROC curve analysis was used to evaluate the predictive value of PP at different tidal volume thresholds, and 8 ml/kg best identified different behaviors. Overall, the cardiac index increased from 2.66 (2.00–3.47) to 3.04 (2.44–3.96) l/min m² ( P <0.001). It increased by more than 15% in 33 patients (fluid responders). Pulmonary artery occluded pressure was lower and PP higher in responders than in non-responders, but fluid responsiveness was better predicted with PP (ROC curve area 0.76±0.06) than with pulmonary artery occluded pressure (0.71±0.07) and right atrial (0.56±0.08) pressures. Despite similar response to fluid challenge in low (<8 ml/kg) and high tidal volume groups, the percent of correct classification of a 12% PP was 51% in the low tidal volume group and 88% in the high tidal volume group.Conclusions PP is a reliable predictor of fluid responsiveness in mechanically ventilated patients only when tidal volume is at least 8 ml/kg.Electronic Supplementary Material Supplementary material is available in the online version of this article at     

Compartmentalisation of cytokines and cytokine inhibitors in ventilator-associated pneumonia

Objective To examine whether cytokine concentrations change in the pulmonary compartment during the development of ventilator-associated pneumonia (VAP).Design Non-directed bronchial lavage (NBL) was performed every 48 h in critically ill mechanically ventilated patients. Serial measurements of the cytokines tumor necrosis factor (TNF) , interleukin (IL)-1, IL-1, IL-6, and IL-10 and the cytokine inhibitors soluble TNF receptor type I (sTNFRI), IL-1 receptor antagonist (IL-1Ra) and soluble IL-1 receptor II (sIL-1RII) were performed on the NBL fluid and matching plasma samples by ELISA.Setting An adult medical and surgical university hospital intensive care unit.Patients Nine patients who developed VAP and nineteen patients who did not develop VAP served as controls.Interventions None.Results Plasma concentrations of the measured cytokines and cytokine inhibitors did not change significantly in any patients. In control patients, NBL fluid concentrations of sIL-1RII decreased significantly over time (P=0.01). In patients who developed VAP, NBL fluid concentrations of TNF, sTNFRI, IL-1, and IL-1 increased significantly (P=0.002, P=0.03, P=0.04 and P=0.02, respectively). Furthermore, NBL fluid/plasma concentration ratios for TNF, sTNFRI, IL-1, IL-1Ra and IL-6 increased significantly as VAP developed (P=0.001, P=0.001, P=0.04, P=0.03, and P=0.04, respectively).Conclusion Our results suggest that the production of important cytokines and cytokine inhibitors is compartmentalised within the lung in critically ill mechanically ventilated patients who develop VAP.     

Pharmacognosie du ginseng: état des lieux. La notion d’adaptogène mise en question*

Résumé: A loccasion dune mise au point critique sur les principes actifs du ginseng, on confirme quil est toujours difficile de se faire une opinion claire et précise des qualités de cette «fabuleuse» racine. La majorité des articles tourne autour de sa qualité dadaptogène, terme quil est urgent de définir avec précision pour en finir avec les discours tautologiques. Restent enfin lenjeu commercial qui pousse à lhagiogra-phie et lexotisme qui exalte la crédulité des consommateurs.* Communication présentée lors de la 12^e Journée universitaire de lAMPP septembre 2003 : Ginseng et autres plantes adaptogènes.     

Ultrasonic-enhanced gentamicin transport through colony biofilms of <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> and <Emphasis Type="Italic">Escherichia coli</Emphasis>

The hypothesis that ultrasound increases antibiotic transport through biofilms of Escherichia coli and Pseudomonas aeruginosa was investigated using colony biofilms. Biofilms grown on membrane filters were transferred to nutrient agar containing 50µg/ml gentamicin. A smaller filter was placed on top of the biofilm and a blank concentration disk was situated atop the filter. Diffusion of antibiotic through the biofilms was allowed for 15, 30, or 45min at 37°C. Some of these biofilms were exposed to 70-kHz ultrasound and others were not. Each concentration disk was then placed on a nutrient agar plate spread with a lawn of E. coli. The resulting zone of inhibition was used to calculate the amount of gentamicin that was transported through the biofilm into the disk. The E. coli and P. aeruginosa biofilms grown for 13 and 24h were exposed to two different ultrasonic power densities. Ultrasonication significantly increased the transport of gentamicin through the biofilm. Insonation of biofilms of E. coli for 45min more than doubled the amount of gentamicin compared to their noninsonated counterparts. For P. aeruginosa biofilms, no detectable gentamicin penetrated the biofilm within 45min without ultrasound; however, when insonated (1.5W/cm²) for 45min, the disks collected more than 0.45µg antibiotic. Ultrasonication significantly increased transport of gentamicin across biofilms that normally blocked or slowed gentamicin transport when not exposed to ultrasound. This enhanced transport may be partially responsible for the increased killing of biofilm bacteria exposed to combinations of antibiotic and ultrasound.     

Combined effects of NO inhalation and intravenous PGF2α on pulmonary circulation and gas exchange in an ovine ARDS model

Objectives Inhalation of nitric oxide (NO) selectively dilates pulmonary vessels in well-ventilated regions. Prostaglandin F₂ (PGF₂) is a vasoconstrictor and is reported to enhance hypoxic pulmonary vasoconstriction. The objective of this study was to examine whether the combination of intravenous PGF₂ and inhaled NO in ARDS lungs has a beneficial effect on oxygenation.Design We investigated the effect of intravenous PGF₂ infusion (0.05–10.0 g/kg per min) with and without NO inhalation (60 ppm) on the hemodynamics and gas exchange in an ovine ARDS model, examining the pulmonary artery pressure versure the flow plot by varying cardiac output.Measurements and results After lung lavage, NO inhalation reduced the mean pulmonary arterial pressure (MPAP) by decreasing the zero-flow pressure intercept from 10.6±3.8 (mean±SD) to 8.5±3.8 mmHg (p<0.05) with no significant change in slope. NO inhalation improved PaO₂ from 56±12 to 84±38 mmHg (p<0.005) and reduced pulmonary shunt from 65±5 to 53±8% ( ) (p<0.001). The dose-dependent effects of PGF₂ infusion were: (1) increased MPAP attributed to an increased slope in pulmonary artery pressure-flow plot; (2) decreased cardiac index; (3) decreased with unchanged PaO₂. The dose-dependent decrease in after PGF₂ infusion was attributed to the decreased cardiac output.Conclusions It is suggested that inhalation of NO reduced the critical vascular pressure near alveoli without affecting upstream vessels, while infused PGF₂ constricted the larger upstream pulmonary artery vessels without appreciably affecting the critical pressure. Inhalation of NO into well-ventilated lung areas shifted perfusion to well-oxygenated areas, and there was no supplemental shift in blood flow by adding an infusion of PGF₂.This study was supported by USPHS grant HL 42391 to W.M.Z. and a Kitasato Research Foundation grant to H.K.     

Oxygenation remains unaffected by increased inspiration-to-expiration ratio but impairs hemodynamics in surfactant-depleted piglets

Objectives Prolongation of inspiratory time is used to reduce lung injury in mechanical ventilation. The aim of this study was to isolate the effects of inspiratory time on airway pressure, gas exchange, and hemodynamics, while ventilatory frequency, tidal volume, and mean airway pressure were kept constant.Design Randomized experimental trial.Setting Experimental laboratory of a University Department of Anesthesiology and Intensive Care.Animals Twelve anesthetised piglets.Interventions After lavage the reference setting was pressure-controlled ventilation with a decelerating flow; IE was 11, and PEEP was set to 75% of the inflection point pressure level. The IE ratios of 1.51, 2.31, and 41 were applied randomly. Under open lung conditions, mean airway pressure was kept constant by reduction of external PEEP.Measurement and results Gas exchange, airway pressures, hemodynamics, functional residual capacity (SF₆ tracer), and intrathoracic fluid volumes (double indicator dilution) were measured. Compared to the IE of 11, PaCO₂ was 8% lower, with IE 2.31 and 41 (p0.01) while PaO₂ remained unchanged. The decrease in inspiratory airway pressure with increased inspiratory time was due to the response of the pressure-regulated volume-controlled mode to an increased IE ratio. Stroke index and right ventricular ejection fraction were depressed at higher IE ratios (SI by 18% at 2.31, 20% at 41; RVEF by 10% at 2.31, 13% at 41;p0.05).Conclusion Under open lung conditions with an increased IE ratio, oxygenation remained unaffected while hemodynamics were impaired.This study was supported by the Swedish Medical Research Council (project 4252), the Swedish Heart-Lung Foundation, Stockholm, Sweden, and the Laerdal Foundation for Acute Medicine, Stavanger, Norway     

Invisible diseases and the doctor-patient relationship

Abstract Headaches can be considered as a paradigm for the so-called invisible diseases; difficulties that headache patients encounter and complain from often relate more to the lack of understanding and communication than to lack of a cure by their doctors. Even when treatment is available, although symptoms are relieved, this might not cure the suffering and the burden caused by headache. This paper will present the difference between disease and illness, will highlight difficulties encountered by patients with invisible diseases and will underline how these difficulties might be reduced by a better doctor–patient relationship. The physician who acknowledges and considers the subjective aspects of the illness, has important elements both for a personalised diagnosis and for a therapy that the patient will be able and willing to follow. The physician has to improve and to train his/her human capabilities in order to have a good relationship with the ill person, and not only to use his/her technical skills for individualising and curing the disease in the patients body.*Section Editor     

Intrathoracic blood volume accurately reflects circulatory volume status in critically ill patients with mechanical ventilation

Positive pressure ventilation in patients with acute respiratory failure (ARF) may render the interpretation of central venous pressure (CVP) or pulmonary wedge pressure (PCWP) difficult as indicators of circulating volume. The preload component of cardiac (CI) and stroke index (SI) is also influenced by the increased intrathoracic pressures of positive pressure ventilation. Moreover CI and SI do not indicate volume status exclusively but also contractility and afterload. We investigated whether intrathoracic blood volume (ITBV) more accurately reflects blood volume status and the resulting oxygen transport (DO₂). CVP, PCWP, cardiac (CI) and stroke index (SI) were measured, oxygen transport index (DO₂I) and oxygen consumption index (VO₂I) were calculated in 21 ARF-patients. Ventilatory patterns were adjusted as necessary. CI, SI and intrathoracic blood volume index (ITBVI) were derived from thermal dye dilution curves which were detected with a 5 F fiberoptic thermistor femoral artery catheter and fed into a thermaldye-computer. All data were collected in intervals of 6h. There were 224 data sets obtained. Linear regression analysis was performed between absolute values as well as between the 6 h changes (prefix ). The following correlation coefficients were determined: CVP/CI and PCWP/CI 0.01 and –0.142 (p<0.05); CVP/SI and PCWP/SI –0.108 and –0.228 (p<0.01); ITBVI/CI and ITBV/SI 0.488 (p<0.01) and 0.480 (p<0.01); ITBVI and DO₂I 0.460 (p<0.01); CVP/CI and PCWP/CI –0.069 and–0.018; CVP/SI and PCWP/SI –0.083 and –0.009; ITBVI/CI and ITBVI/SI 0.715 (p<0.01) and 0.646 (p<0.01); ITBVI and DO₂I 0.707 (p<0.01). We conclude that in mechanically ventilated patients ITBV is a suitable indicator of circulating blood volume.     

New aspects of pulmonary mechanics: ‘slowly” distensible compartments of the respiratory system,identified by a PEEP step maneuver

Objective The aims of the present study were 1) to evaluate a method for identification of slowly distensible compartments of the respiratory system (rs), which are characterized by long mechanical time constants (RC) and 2) to identify slowly distensible rs-compartments in mechanically ventilated patients.Design Prospective studyon a physical lung model.Setting Intensive Care Unit, University Hospital, Tübingen.Patients and participants 19 patients with severe lung injury (acute respiratory distress syndrome, ARDS) and on 10 patients with mild lung injury.Measurements and results Positive end-expiratory pressure (PEEP)-increasing and-decreasing steps of about 5 cmH₂O were applied and the breath-by-breath differences of inspiratory and expiratory volumes (V) were measured. The sequence of Vs were analyzed in terms of volume change in the fast compartment (V_fast), the slow compartment (V_slow), total change in lung volume (VL) and mechanical time constant of the slow compartment (RC_slow). Thirty-eight measurements in a lung model revealed a good correlation between the preset V_slow/VL and V_slow/VL measured: r²=0.91 The V_slow/VL measured amounted to 0.94±0.15 of V_slow/VL in the lung model. RC_slow measured was 0.92±0.43 of the RC_slow reference. Starting from a PEEP level of 11 cmH₂O PEEP-increasing and PEEP-decreasing steps were applied to the mechanically ventilated patients. Three out of ten patients with mild lung injury (30%) and 7/19 patients with ARDS (36.8%) revealed slowly distensible rscompartments in a PEEP-increasing step, whereas 15/19 ARDS patients and 1/10 patients with mild lung injury showed slowly distensible rs-compartments in a PEEP-decreasing step (78.9% vs 10%,P<0.002, chi-square test).Conclusions The gas distribution properties of the respiratory system can be easily studied by a PEEP-step maneuver. The relative contribution of the slow units to the total increase of lung volume following a PEEP step could be adequately assessed. Slowly distensible rs-compartments could be detected in patients with severe and mild lung injury, however significantly more ARDS patients revealed slow rs-compartments in PEEP-decreasing steps. The influence of slowly distensible rs-compartments on pulmonary gas exchange is unknown and has yet to be studied.The work was performed at the Klinik für Anaesthesiologie und Transfusionsmedizin der Universität Tübingen     

The patients’ perceptions of migraine and chronic daily headache: a qualitative study

This study aimed to gain insight into the management of migraine and chronic daily headache (CDH) from the patients perspective. This article outlines the patients perceptions of migraine and chronic daily headache. Thirteen semi–structured interviews were carried out with patients suffering from IHS migraine. Five patients, due to their headache frequency of more than 15 headache days per month, were classed as CDH patients. The data were transcribed verbatim and analysed in accordance with the grounded theory methodology. The main themes were: headaches, impact and headaches related to health issues. The theme headaches was sub-divided into their pain and symptoms, differentiating between their headaches and perceptions of headaches as barriers and facilitators to management. The patients perceptions of migraine and CDH were sometimes conflicting and influenced the patients management behaviours. The qualitative methodology may help to inform doctors, other healthcare professionals and headache researchers about the patients perspective and possibly develop future headache research, care and education.     

Plaidoyer pour la tisane médicinale

Résumé: La tisane nest pas uniquement un apport deau. Il sagit dune préparation médicinale utile en médecine et en phytothérapie. Elle doit obéir à certains critères pour être de qualité : qualité de la plante, temps dinfusion, conditions dutilisation, correction du goût. La teneur en principe actif est variable, mais elle est effective, quoiquelle dépende de plusieurs facteurs qui en déterminent lefficacité. Des exemples de tisanes pour la pédiatrie sont donnés.