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Resume Objectif Parce que la radiographie thoracique reste l’examen realise en premiere intention pour l’exploration du parenchyme pulmonaire en reanimation, nous avons compare l’echographie pulmonaire a la radiographie thoracique. Type de l’etude Etude observationnelle prospective. Patients et methodes Une echographie et une radiographie etaient demandees simultanement chez 50 patients necessitant une exploration du parenchyme pulmonaire. Chaque examen a ete interprete de maniere independante par un medecin-reanimateur. Les anomalies etaient classees en syndrome alveolo-interstitiel, condensation alveolaire et epanchement pleural. Une analyse de concordance a ete realisee entre les resultats des deux techniques. Les delais entre la demande et l’interpretation des examens, ainsi que le degre de concordance interobservateur pour l’echographie ont egalement ete analyses. Resultats La concordance kappa entre l’echographie pulmonaire et la radiographie thoracique etait de 0,42 ; 329 anomalies ont ete mises en evidence dont 156 par les deux techniques, 31 par la radiographie seule et 142 par l’echographie seule. La concordance interobservateur etait de 0,86. L’echographie a ete realisee dans des delais plus courts (14,8 ± 6,9 min vs 44,2 ± 21,4 min). Conclusion Une concordance moderee etait retrouvee entre l’echographie pulmonaire et la radiographie thoracique pour le diagnostic des syndromes alveolo-interstitiels, alveolaires et des epanchements pleuraux en reanimation. Ce resultat est principalement explique par le nombre plus eleve d’anomalies retrouvees a l’echographie. Puisqu’elle permet un diagnostic rapide, avec une bonne reproductibilite et une faisabilite elevee, l’echographie pourrait etre une technique d’exploration du parenchyme pulmonaire alternative en reanimation.

Resume Objectifs. – Evaluer l’attitude des anesthesistes concernant l’administration perioperatoire des betabloquants (BB), notamment l’introduction preoperatoire de BB pour prevenir la survenue de complications cardiaques postoperatoires. Methodes. – Realisation d’une enquete de pratique par envoi d’un questionnaire comportant 20 items aupres de 700 anesthesistes des departements de l’Ain, de l’Isere, de la Loire et du Rhone. Resultats. – Le taux de reponses etait de 30 %. Quatre-vingt-huit pour cent des repondeurs declaraient administrer le traitement BB prescrit de facon chronique le jour de l’intervention chirurgicale avec la premedication. Trente-sept pour cent des repondeurs introduisaient frequemment ou systematiquement un traitement BB en periode preoperatoire chez les patients a risque cardiovasculaire devant subir une chirurgie majeure. Le BB le souvent prescrit etait l’atenolol (68 %). Soixante et onze pour cent des praticiens introduisant des BB en periode preoperatoire demandaient un avis cardiologique avant la prescription du traitement par BB. Conclusion. – La poursuite perioperatoire d’un traitement BB pris de facon chronique parait faire partie de la pratique courante. En revanche, la prescription preoperatoire d’un traitement BB chez le patient a haut risque cardiovasculaire reste insuffisante et correlee a un avis cardiologique.

Background Ropivacaine has been claimed to produce less motor block than bupivacaine during epidural analgesia. However, this advantage has not been clearly confirmed in obstetric studies using low analgesic concentrations in a ratio close to that suggested to be equianalgesic. Methods This double‐blind, randomized, prospective study was performed in 140 parturients who requested epidural analgesia. After a lumbar epidural catheter had been placed, patients received either 0.10% bupivacaine plus sufentanil 0.5 µg ml–1 or 0.15% ropivacaine plus sufentanil 0.5 µg ml–1 followed by a continuous infusion. Additional boluses were used for inadequate levels of analgesia. Visual analogue pain scores, motor block, level of sensory block, supplementary boluses and main characteristics of labour were recorded. Results No differences were observed between the two groups for pain scores, total volume of anaesthetic solution used [59 (23) and 57 (24) ml in the bupivacaine and ropivacaine groups respectively], duration of labour, mode of delivery, side‐effects or satisfaction score. The incidence of motor block was not statistically different between the groups (54 and 69% in the bupivacaine and ropivacaine groups respectively, P=0.07). However, when motor block occurred, survival analysis showed that it occurred sooner in the course of labour with ropivacaine compared with bupivacaine (log rank test, P=0.012). Conclusion Combined with sufentanil 0.5 µg ml–1, 0.10% bupivacaine and 0.15% ropivacaine produce effective and equivalent analgesia during labour, with similar incidences of motor block. Br J Anaesth 2002; 88: 809–13

Due to their special metabolic pathway, medium-chain triglycerides (MCT) have been claimed to be oxidized more extensively, compared with long-chain triglycerides (LCT), when administered as a parenteral nutritional support. This enhanced lipid oxidation rate of MCT emulsions could be particularly disclosed in hyperglycemic and hyperinsulinemic conditions. In an attempt to further elucidate this question, we measured substrate oxidation rates in critically ill patients liable to experience such metabolic conditions, that is to say postoperative patients after esophageal resection receiving 1.5 times their measured energy expenditure (n = 12) or after liver transplantation (n = 8). These patients received either LCT or MCT-LCT emulsions. The metabolic measurements were performed simultaneously by two methods, namely indirect calorimetry and isotopic methods based on natural abundance of nutrients. Although both groups of patients were hyperglycemic and hyperinsulinemic, the measured carbohydrate and lipid oxidation rates were not different with whatever type of lipid was administered. The MCT-LCT emulsions did not offer clear-cut advantages over LCT emulsions in critically ill patients when lipid energetic fate was considered.

Patients with coronary artery disease are particularly at risk perioperatively, as myocardial infarction, unstable angina, severe arrhythmia and cardiac death may occur. These events are often preceded by prolonged silent myocardial ischaemia (MI). Moreover, perioperative MI predicts long-term adverse cardiac outcome. Therefore, it is logical to prevent and treat MI. However, the detection of perioperative MI is difficult because of low sensitivity of ST-segment monitoring, low specificity of echocardiography and insufficient availability of equipment for its monitoring. A pragmatic approach is described, including preoperative consideration of myocardial revascularization prior to non-cardiac surgery and perioperative administration of antianginal agents; the effects of clonidine are discussed as well. The role of anaesthetic techniques and normovolaemic haemodilution is considered. MI episodes may be prevented or their duration may be shortened by treating tachycardia, hypotension and, possibly, hypertension. The risks of MI are particularly high during the postoperative period because increased global oxygen consumption associated with recovery, ventilator weaning, shivering and pain may lead to tachycardia and increased ventricular load. These factors must be taken into account in order to prevent MI and improve postoperative cardiac outcome.

We report the case of a 30-year-old woman with a post-partum haemorrhage and foetal death caused by a leptospirosis infection. This disease could induce a coagulopathy associated with foetal death and potential hazard for epidural analgesia.

Conflicting results have been found regarding correlations between right atrial pressure (RAP) and inferior vena cava (IVC) diameter in mechanically ventilated patients. This finding could be related to an increase in intra-abdominal pressure (IAP). This study was designed to clarify whether variations in IVC flow rate caused by positive pressure ventilation are associated with changes in the retrohepatic IVC cross-section (ΔIVC) during major changes in volume status and IAP. Nine pigs were anesthetized, mechanically ventilated and equipped. IAP was set at 0, 15 and 30 mmHg during two conditions, i.e. normovolemia and hypovolemia, generated by blood removal to obtain a mean arterial pressure value lower than 60 mmHg. At each IAP increment, cardiac output, IVC flow and surface area were respectively assessed by flowmeters and transesophageal echocardiography. At normal IAP, even in presence of respiratory changes in IVC flows, no ΔIVC were observed during the two conditions. At high IAP, neither ΔIVC nor modulations of IVC flow were observed whatever the volemic status. The majority of animals with an IVC area of less than 0.65 cm(2) showed evidence of IAP greater than RAP values. Negative RAP-IAP pressure gradients were found to occur with an IVC area of less than 0.65 cm(2), suggesting that IVC dimensions determined using standard ultrasound techniques may indicate the direction of the RAP-IAP gradient. The clinical relevance of the present findings is that volume status should not be estimated from retrohepatic IVC dimensions in cases of high IAP.

Measurement of the nutrient oxidation rate with 13C as a tracer requires knowledge of the value of its coefficient of fractional recovery in the expired gas (FR). We measured FR in nine intensive care patients who were mechanically ventilated and received total parenteral nutrition. NaH13CO3 was administered at a priming dose (3.75 mumol.kg-1.min-1) followed by a continuous infusion (0.05 mumol.kg-1.min-1). Metabolic rate and pulmonary carbon dioxide elimination (VCO2) were measured by using a mass-spectrometer system. The 13C-12C ratio was measured in the expired gas with an isotopic-ratio mass spectrometer and FR was calculated by using standard equations. The average value of FR was 0.899 +/- 0.026 (means +/- SE) and remained stable for each patient on 2 consecutive days. Between patients, the coefficient of variation of FR was 8.6%. Metabolic rate was the only physiological factor found to affect the FR value.

In an experimental model we investigated the effects of a gradual increase in intra-abdominal pressure (IAP) on the central circulation.Seven pigs were anaesthetized, mechanically ventilated and instrumented. IAP was gradually increased by 5 mm Hg up to 30 mm Hg by abdominal banding in normovolaemic animals, and then they were made hypovolaemic after blood withdrawal. Right atrial pressure (RAP) and left ventricular end-diastolic pressure (LVEDP) at each step and aortic, femoral and inferior vena cava blood flows were measured. Left ventricular end-diastolic area (LVEDA) was determined using epicardial echocardiography.Cardiac output maintained at mild IAP was reduced to 76 (24)% of the initial value at 30 mm Hg IAP [mean (sd)] in normovolaemic animals, and 72 (22)% (P0.001) in hypovolaemic animals. In normovolaemic animals the LVEDA and LVEDP were significantly increased at an IAP of 10 and 15 mm Hg by 26 (24)% and 38 (23)%, respectively. At these IAP values, the difference between the RAP and IAP was positive. When this gradient became negative, that is beyond 15 mm Hg in normovolaemia and for all IAP values in hypovolaemic animals, the LVEDA declined, reaching 78 (16)% and 62 (22)% (P0.05) of the initial values in normovolaemic and hypovolaemic groups at the highest IAP value.These results showed that a gradual increase in IAP led to a redistribution of abdominal blood volume towards the thoracic compartment, at IAP lower than 15 mm Hg in normovolaemia, and at its expense at higher values of IAP. In hypovolaemia there was no thoracic compartment gain. Whereas the absolute or transmural RAPs were not informative of the direction of this blood shift, an RAP greater than IAP was associated with an intrathoracic compartment gain.

The effects of lipid administration on carbohydrate oxidation rate remain controversial, particularly in critically ill patients. The aim of this study was to determine the effects of these patients of a continuous lipid infusion on glucose metabolism using indirect calorimetry and stable isotopes. We studied seven patients, mechanically ventilated, during two consecutive 24-h periods. Throughout the first period they received a continuous infusion of glucose (2 mg.kg-1.min-1) and amino acids. During the second period, in addition to the glucose, they received a continuous infusion of 1 mg.kg-1.min-1 of long-chain triglycerides emulsion. Substrate oxidation rates were calculated from pulmonary gas exchange and nitrogen excretion measurements. Glucose kinetic parameters were measured using primed constant infusions of [6,6-2H2]glucose and [1-13C]glucose. The lipid infusion did not modify the glucose metabolism parameters; 45% of the lipid supply was stored.

Introduction The aim of this study was to evaluate dynamic indices of fluid responsiveness in a model of intra-abdominal hypertension. Methods Nine mechanically-ventilated pigs underwent increased intra-abdominal pressure (IAP) by abdominal banding up to 30 mmHg and then fluid loading (FL) at this IAP. The same protocol was carried out in the same animals made hypovolemic by blood withdrawal. In both volemic conditions, dynamic indices of preload dependence were measured at baseline IAP, at 30 mmHg of IAP, and after FL. Dynamic indices involved respiratory variations in stroke volume (SVV), pulse pressure (PPV), and systolic pressure (SPV, %SPV and Δdown). Stroke volume (SV) was measured using an ultrasound transit-time flow probe placed around the aortic root. Pigs were considered to be fluid responders if their SV increased by 15% or more with FL. Indices of fluid responsiveness were compared with a Mann-Whitney U test. Then, receiver operating characteristic (ROC) curves were generated for these parameters, allowing determination of the cut-off values by using Youden's method. Results Five animals before blood withdrawal and all animals after blood withdrawal were fluid responders. Before FL, SVV (78 ± 19 vs 42 ± 17%), PPV (64 ± 18 vs 37 ± 15%), SPV (24 ± 5 vs 18 ± 3 mmHg), %SPV (24 ± 4 vs 17 ± 3%) and Δdown (13 ± 5 vs 6 ± 4 mmHg) were higher in responders than in non-responders (P < 0.05). Areas under ROC curves were 0.93 (95% confidence interval: 0.80 to 1.06), 0.89 (0.70 to 1.07), 0.90 (0.74 to 1.05), 0.92 (0.78 to 1.06), and 0.86 (0.67 to 1.06), respectively. Threshold values discriminating responders and non-responders were 67% for SVV and 41% for PPV. Conclusions In intra-abdominal hypertension, respiratory variations in stroke volume and arterial pressure remain indicative of fluid responsiveness, even if threshold values identifying responders and non-responders might be higher than during normal intra-abdominal pressure. Further studies are required in humans to determine these thresholds in intra-abdominal hypertension.

After completion of abdominal aortic graft, 29 patients received an i.v. infusion of placebo (n = 16) or clonidine 7 micrograms kg-1 (n = 13) over 120 min in a double-blind study. Cardiovascular variables were measured and plasma samples obtained up to 5 h after arrival in the recovery room, for assay of noradrenaline, adrenaline, vasopressin and renin concentrations. Noradrenaline, adrenaline and vasopressin concentrations decreased in the clonidine group throughout recovery (P less than 0.001, 0.05 and 0.05, respectively, vs placebo). Heart rate was less in the clonidine group (P less than 0.01). There was no significant difference in mean arterial pressure between groups. Stroke volume was larger (P less than 0.01) and there were fewer episodes of hypertension (P less than 0.05) and tachycardia in the clonidine group. In addition, a reduction in the number of circulatory interventions (P less than 0.05) and episodes of shivering was noted in the clonidine group. Mean (SD) postoperative volume requirements were larger in the clonidine group (total postoperative input: clonidine 1462 (604) ml; placebo 1064 (348) ml (P less than 0.05]. These data are consistent with the observation that clonidine modifies endocrine and circulatory status after major surgery.

This study is an investigation into the effects of different carbohydrate-to-lipid ratios on CO2 production in postoperative patients and the determination of the substrate oxidation rates induced by long-chain triglycerides (LCT) or a mixture of long- and medium-chain triglycerides (MCT/LCT) at various carbohydrate-to-lipid ratios. Two groups of eight patients randomly received either LCT or MCT/LCT emulsions. Total caloric intake was set at the measured energy expenditure provided at three different glucose-to-lipid ratios (70:30, 50:50, 30:70). We used long-term indirect calorimetry with a mass spectrometer system and measurement of natural enrichment in 13C of expired CO2 and plasma glucose. The carbon dioxide production and minute ventilation were not different among the different glucose-to-lipid ratios, whatever the type of lipid. Increasing the lipid supply up to 70% of nonprotein caloric intake led to an only minor increase in lipid oxidation rate and thus to a net fat deposit. We conclude that large amounts of lipid (LCT or MCT/LCT) were not of interest in such patients.