Ability of esCCO to track changes in cardiac output.

BACKGROUND: We investigated whether cardiac output measured with pulse wave transit time (esCCO, Nihon Kohden, Tokyo, Japan) is able to track changes in cardiac output induced by an increase in preload (volume expansion/passive leg-raising) or by changes in vasomotor tone (variation in norepinephrine dosage) in critically ill patients. METHODS: Eighty patients for whom the decision to give fluid (500 mL of saline over 15 min) (n=20), to perform passive leg-raising (n=20), and to increase (n=20) or to decrease (n=20) norepinephrine were included by the physician. Cardiac output was measured with pulse wave transit time (CO-esCCO) and transthoracic echocardiography (CO-TTE) before and after therapeutic intervention. RESULTS: Comparison between CO-TTE and CO-esCCO showed a bias of -0.7 l min(-1) and limits of agreement of -4.4 to 2.9 l min(-1), before therapeutic intervention and a bias of -0.5 l min(-1) and limits of agreement of -4.2 to 3.2 l min(-1) after therapeutic intervention. Bias was correlated with systemic vascular resistance (r(2)=0.60, P<0.0001). Percentage error was 61% before and 59% after therapeutic intervention. Considering the overall data (n=80), the concordance rate was 84%, polar plot analysis revealed an angular bias (sd) of -11°(35°) and radial limits of agreement of (sd 50°). With regard to passive leg-raising and volume expansion groups (n=40), the concordance rate was 83%, the angular bias (sd) was -20°(36°) and radial limits of agreement ( 50°). Considering variations in norepinephrine dosage groups (n=40), the concordance rate was 86%, the angular bias (sd) was -1.8°(33°) and radial limits of agreement (40°). CONCLUSIONS: esCCO was not able to track changes in cardiac output, induced by an increase in preload or by variations in vasomotor tone. Therefore, esCCO cannot guide haemodynamic interventions in critically ill patients.

Abilities of pulse pressure variations and stroke volume variations to predict fluid responsiveness in prone position during scoliosis surgery.

BACKGROUND: Pulse pressure variation (PPV) and stroke volume variation (SVV) are robust indicators of fluid responsiveness in mechanically ventilated supine patients. The aim of the study was to evaluate the ability of PPV and SVV to predict fluid responsiveness in mechanically ventilated patients in the prone position (PP) during scoliosis surgery. METHODS: Thirty subjects were studied after the induction of anaesthesia in the supine position [before and after volume expansion (VE) with 500 ml of hetastarch 6%] and in PP (immediately after PP and before and after VE). PPV, SVV, cardiac output (CO), and static compliance of the respiratory system were recorded at each interval. Subjects were defined as responders (Rs) to VE if CO increased > or =15%. RESULTS: Three subjects were excluded. In the supine position, 16 subjects were Rs. PPV and SVV before VE were correlated with VE-induced changes in CO (r(2)=0.64, P<0.0001 and r(2)=0.56, P<0.0001, respectively). Fluid responsiveness was predicted by PPV >11% (sensitivity=88%, specificity=82%) and by SVV >9% (sensitivity=88%, specificity=91%). PP induced an increase in PPV and SVV (P<0.0001) and a decrease in the static compliance of the respiratory system (P<0.0001). In PP, 17 patients were Rs. PPV and SVV before VE were correlated with VE-induced changes in CO (r(2)=0.59, P<0.0001 and r(2)=0.55, P<0.0005, respectively). Fluid responsiveness was predicted in PP by PPV >15% (sensitivity=100%, specificity=80%) and by SVV >14% (sensitivity=94%, specificity=80%). CONCLUSIONS: PP induces a significant increase in PPV and SVV but does not alter their abilities to predict fluid responsiveness.

Rotation thromboelastometry detects thrombocytopenia and hypofibrinogenaemia during orthotopic liver transplantation.

BACKGROUND: Orthotopic liver transplantation can be associated with haemorrhage, particularly in patients with severe liver dysfunction. We assessed the value of rotation thromboelastometry (ROTEM) to monitor coagulation in the operating theatre, its correlation with routine laboratory findings, and its ability to guide platelet (Plt) and fibrinogen (Fg) transfusion. METHODS: Twenty-three patients were included in this prospective observational study. Laboratory tests and ROTEM tests (EXTEM, INTEM, FIBTEM, and APTEM) were performed six times during the procedure. Correlations between laboratory findings and ROTEM parameters were sought. Thresholds for ROTEM parameters were determined with receiver-operating characteristic (ROC) curve analysis according to Plt count and Fg levels. RESULTS: Clot amplitude at 10 min (A10) of EXTEM was well correlated with Plt count and Fg levels (R(2)=0.46 and 0.52, respectively, P<0.0001). FIBTEM A10 was correlated with Fg (R(2)=0.55, P<0.0001). ROC analysis showed that EXTEM A10 with a threshold of 29 mm predicted thrombocytopenia with a sensitivity of 79% and a specificity of 60%, and a threshold of 26 mm predicted hypofibrinogenaemia with a sensitivity of 83% and a specificity of 75%. CONCLUSIONS: ROTEM is useful for the global assessment of coagulation in the operating theatre. EXTEM was the most informative for assessing the whole coagulation process and A10 showed value in guiding Plt and Fg transfusion.

[Fatal haemorrhagic rift valley fever: a case at Madagascar]. / Forme hémorragique grave de la fièvre de la Vallée du Rift: une observation à Madagascar.

Rift valley fever (RVF) is a viral zoonosis that can also infect humans. Haemorrhagic RVF is a severe potentially fatal form of the disease. Although haemorrhagic RVF accounts for only 1% of all infections, death occurs in up to 5% of cases. The purpose of this report is describe a severe case of haemorrhagic RVF observed in a 22-year-old cattle breeder admitted to the intensive care units of the Joseph Raseta Befelatanana University Hospitals in Antananarivo. The disease presented as an infectious syndrome but hemorrhagic manifestations developed early (day 2). They consisted of diffuse haemorrhage events (haemorrhagic vomit, gingival haemorrhage, skin haemorrhage, urinary haemorrhage, and haemorrhage on the venous puncture site). In spite of intensive care, haemorrhagic complications lead to death on day 4 of clinical evolution. Laboratory findings demonstrated alteration in liver function and coagulation disturbances. Multiple organ failure was also observed.

Optimal dose of sufentanil in children for intubation after sevoflurane induction without neuromuscular block.

BACKGROUND: We studied 63 ASA I children (age 2-8 yr) to determine the sufentanil dose needed to facilitate intubation under excellent conditions after inhalation induction with various end-tidal concentrations of sevoflurane without neuromuscular block. METHODS: Subjects were allocated randomly to receive sevoflurane end-tidal concentrations (e'(sevo)) of 2.5%, 3%, or 3.5%. Anaesthesia was induced with sevoflurane 6% without nitrous oxide for 2 min, and then inspired sevoflurane concentration was adjusted to keep e'(sevo) at 2.5%, 3%, or 3.5% according to the group. Subjects received i.v. sufentanil according to an 'up and down' design. Tracheal intubation by direct laryngoscopy was performed 6 min after sufentanil injection. Intubation was considered successful, if intubation conditions were excellent as determined by the laryngoscopist. RESULTS: The ED(50) [effective dose for 50% of subjects; mean (sd)] of sufentanil required for excellent intubation conditions was 0.6 (0.12), 0.32 (0.10), or 0.11 (0.07) microg kg(-1) for e'(sevo) of 2.5%, 3%, or 3.5%, respectively. Using logistic analysis, the 95% effective dose (ED(95)) of sufentanil was 1.02 [95% confidence intervals (CI) 0.31-1.74] microg kg(-1), 0.58 (95% CI 0.17-0.99) microg kg(-1), or 0.28 (95% CI 0.04-0.52) microg kg(-1) for e'(sevo) of 2.5%, 3%, or 3.5%, respectively. CONCLUSIONS: Excellent intubation conditions could be obtained in children after inhalation induction with low sevoflurane concentrations and adjuvant sufentanil.

Validation of a bedside activated clotting time test (Hemochron Jr II Signature) with low dose heparin therapy.

The purpose of this study was to validate a device designed to measure activated clotting time in low-range heparin plasma concentrations (ACT-LR) prospectively during the post-operative period of vascular surgery. Measurement of ACT-LR and activated partial thromboplastin time (APTT) were performed before heparinisation (T0) and at the end of surgery (T1). ACT-LR(T1) and DeltaACT-LR (defined as ACT-LR(T1) - ACT-LR(T0)) were evaluated as diagnostic tests for excessive anticoagulation, defined by APTT more than twice the laboratory's normal, by Bland-Altman method and receiver operating characteristic (ROC) curves. In 103 patients, mean (SD) ACT-LR was 137 (33) s at T0 and 176 (39) s at T1. Bland-Altman graph did not show a good agreement between APTT and ACT-LR. Areas under ROC curves were 0.82 (95% CI: 0.75-0.89) and 0.87 (95% CI: 0.80-0.93) for ACT-LR(T1) and DeltaACT-LR, respectively. Using a threshold of 32 s for DeltaACT-LR, test sensitivity was 87% (95% CI: 81-93%), specificity was 85% (95% CI: 78-92%), positive predictive value was 90% (95% CI: 84-96%) and negative predictive value was 81% (95% CI: 73-86%). While DeltaACT-LR may have some potential in evaluating excessive anticoagulation in vascular surgery, the poor correlation between ACT-LR and APTT does not support its routine use.

Uncalibrated pulse contour-derived stroke volume variation predicts fluid responsiveness in mechanically ventilated patients undergoing liver transplantation.

BACKGROUND: Stroke volume variation (SVV) is able to predict adequately the individual response to fluid loading. Our objective was to assess whether the SVV measured by a new algorithm (Vigileo; Flotrac) can predict fluid responsiveness. METHODS: Forty mechanically ventilated patients undergoing liver transplantation, who needed volume expansion (VE), were included. VE was done with albumin (4%) 20 mlxBMI over 20 min. SVV, pulse pressure variation (PPV), central venous pressure (CVP), and pulmonary artery occlusion pressure (PAOP) were measured immediately before and after VE. Cardiac output (CO) measured by transthoracic echocardiography (CO-TTE) was used to define responder patients if CO increased by 15% or more after VE, or non-responder otherwise. CO obtained with the pulmonary artery catheter (CO-PAC) and with Vigileo (CO-Vigileo) were also recorded. RESULTS: Five patients were excluded. Seventeen patients were responders (Rs) and 18 were non-responders (NRs). Before VE (i) SVV and PPV were higher in Rs and (ii) CVP and PAOP were lower in Rs. Baseline SVV and PPV correlated with change in CO induced by VE (respectively, r(2)=0.72, P<0.0001; r(2)=0.84, P<0.0001). An SVV threshold of >10% discriminated Rs with a sensitivity of 94% and a specificity of 94%. After VE, the decrease in SVV was significantly correlated with the increase in CO (r(2)=0.51; P<0.0001). There was no difference between the area under the ROC curves of SVV and PPV. After VE, the change in CO-Vigileo was closely correlated with change in CO-TTE (r(2)=0.74, P<0.0001) and with change in CO-PAC (r(2)=0.77, P<0.0001). CONCLUSIONS: The SVV obtained by the Vigileo system may be used as a predictor of fluid responsiveness in patients with circulatory failure after liver transplantation. CO-Vigileo is able to track the change in CO induced by VE.

Validation of the Behavioural Observation Scale 3 for the evaluation of pain in adults.

BACKGROUND: Many behavioural scales are available to assess pain but none are suitable for a quick evaluation of non-sedated and non-geriatric adults. The Behavioural Observation Scale 3 (BOS-3) is short, composed of five items. This study examined its feasibility and diagnostic performances. METHODS: Adult patients were included from medical and surgical departments of the University Hospital of Bordeaux. In a cross-sectional study, BOS-3 was compared to Numerical Rate Scale (NRS) with communicating patients (CP) and Behavioural Scale for the Elderly Person (ECPA2) with non-communicating patients (NCP). Each time, BOS-3 and reference scale were performed by an internal caregiver and an external expert. RESULTS: We included 447 patients: 395 communicating and 52 non-communicating. All patients were assessed by the BOS-3 and the reference test. All BOS-3 were carried out in less than one minute with only four missing data. Its reproducibility (ICC = 0.77 [95% CI 0.73-0.81] with CP and 0.93 [95% CI 0.89-0.97] with NCP) and its internal consistency (Cronbach α = 0.67 with CP and 0.70 with NCP) were good. In non-communicating patients, ROC analysis set a threshold at 3 on 10. Sensitivity was 0.87 [95% CI 0.77-0.96], specificity 0.97 [95% CI 0.93-1.00], positive predictive value 0.93 [95% CI 0.86-0.99] and negative predictive value 0.95 [95% CI 0.89-1.00]. In communicating patients, sensitivity decreased to 0.34 [95% CI 0.28-0.38] but specificity reached 0.96 [95% CI 0.94-0.98] and positive predictive value 0.75 [95% CI 0.70-0.79]. CONCLUSIONS: BOS-3 had good metrological properties in non-communicating adults. With communicating patients, a positive BOS-3 could be an additional tool to confirm pain, when underestimated on the NRS. SIGNIFICANCE: This study describes the diagnostic performances of a behavioral pain assessment scale designed for non-geriatric and non-sedated adults. The results show its validity in non-communicating patients and suggest its usefulness as an ancillary tool in communicating patients in whom simple numerical scales are often insufficient.

[Controlled hypernatremia]. / Hypernatrémie contrôlée.

Hypernatremia exerts its main effect on the brain through the osmotic gradient it creates on either side of the blood brain barrier, which is impermeable to sodium. This generates a transfer of water from the intracellular to the vascular sector leading to temporary cell shrinkage. Osmoregulation permits cerebral cells to accumulate osmoactive molecules in order to restore their initial volume. It has been demonstrated in animals with brain injury that intracellular dehydration occurs essentially in the nonlesioned hemisphere. In most experimental studies, the reduction in cerebral volume obtained by hypertonic saline (HS) perfusion is accompanied by an intracranial pressure decrease, even under hemorrhagic shock conditions. Initially, clinical studies successfully used HS, as an alternative to mannitol, in the treatment of acute and refractory intracranial hypertension. Then continuous infusion of HS, with the objective of inducing hypernatremia, had produced encouraging effects on intracranial pressure control. However, these results were limited to non-randomized studies, without control groups and mainly in pediatric patients. Nevertheless, the use of HS on intracranial hypertension, refractory to conventional treatments, could be reasonable under strict monitoring of natremia as well as its adverse effects.

[Use of activated recombinant FVII in the control of haemorrhage following trauma]. / Contrôle d'une hémorragie traumatique persistante par le facteur VII activé recombinant.

Uncontrolled haemorrhage is a major cause of death in trauma patients: sometimes inaccessible to surgery and often associated with coagulopathy. We report a case of severe blunt pelvic trauma associated with suicide. The conventional treatments were unsuccessful and embolization was impossible. The patient required massive blood product transfusion. A 100 microg/kg recombinant activated factor VII dose was infused, twice. After administration of the first dose, the blood requirement decreased dramatically. Further work and trials are required to assess the safety profile and dose regimen for this drug.

[Microparticles during sepsis and trauma. A link between inflammation and thrombotic processes]. / Microparticules circulantes au cours des traumatismes graves et des sepsis: un élément du couplage inflammation-thrombose.

Sepsis and trauma lead to a sustained activation of monocytes and endothelium. In the vascular compartment, stimulated cells release microparticles. Circulating MP provide an additional procoagulant phospholipid surface enabling the assembly of the clotting enzymes complexes and thrombin generation. Their procoagulant properties rely on the exposition of phosphatidylserine, made accessible after cell stimulation and on the possible presence of tissue factor, the main cellular initiator of blood coagulation. Microparticles constitute the main reservoir of blood-borne tissue factor activity. At sites of endothelium injury, enhanced release or recruitment of procoagulant MP through P-selectin-PSGL-1 pathway could concentrate TF activity above a threshold allowing blood coagulation to be triggered. Converging evidences from experimental or clinical data highlight a role for MP harboring tissue factor in the initiation of disseminated intravascular coagulopathy. In these settings, the pharmacological modulation of MP levels or biological functions through activated protein C or factor VIIa allows challenging issues.

[Induction of anaesthesia with target-controlled inhalation of sevoflurane in adults with the ZEUS anaesthesia machine]. / Induction par inhalation de sévoflurane à objectif de concentration chez l'adulte avec le respirateur ZEUS.

OBJECTIVES: To evaluate if the new anaesthesia platform ZEUS (Dräger Medical) allows the induction of anaesthesia with target-controlled inhalation of sevoflurane. STUDY DESIGN: Prospective clinical study. PATIENTS: Adult ASA I or II patients scheduled for elective surgery under general anaesthesia. METHODS: After preoxygenation during 3 min at 100% oxygen, patients were asked to breathe normally; the target end-tidal concentration of sevoflurane was fixed at 4% without priming of the circuit. Sufentanil (target concentration 0.5 ng/ml) was administered 40 s after. RESULTS: Ten patients (48+/-22 yrs) were included. Sevoflurane was detected in the circuit after 36+/-5 s; the target end-tidal concentration of sevoflurane was obtained at 130+/-19 s. Loss of consciousness was observed after 119+/-7 s. The induction was achieved in all patients without any incident. CONCLUSION: This new anaesthesia system make available the induction of anaesthesia with sevoflurane without priming of the circuit.

[Heat stroke and fulminans hepatitis: is MARS system relevant?]. / Coup de chaleur d'exercice avec hépatite fulminante: intérêt du système MARS?

Exertional heat stroke (EHS) is a life-threatening condition caused by an extreme elevation in core body temperature. Acute liver failure has been reported during EHS justifying liver transplantation in some cases. The Molecular Adsorbent Recirculating System (MARS) could be indicated in such situations. We report a case of a 58-year old patient who suffered acute liver failure occurring after EHS. The patient was referred for liver transplantation and benefited of MARS therapy. After three sessions of MARS, liver function improved progressively and the transplantation was not necessary. The patient completely recovered.

Is bupivacaine a decoupler, a protonophore or a proton-leak-inducer?

This paper deals with the mechanism of bupivacaine uncoupling of oxidative phosphorylation in rat heart mitochondria. By comparison with the effects of QX 572, a permanently charged quaternary amine-type local anesthetic, it is concluded that the effects of bupivacaine and QX 572 may be explained by classical uncoupling behaviour. In the case of bupivacaine this uncoupling effect is mediated through a protonophore-like mechanism, whereas that of QX 572 is simply explained by an electrophoretic uptake.

Effects of the anaesthetic propofol on the calcium-induced permeability transition of rat heart mitochondria: direct pore inhibition and shift of the gating potential.

Mitochondrial calcium exchanges are involved in intracellular calcium homeostasis and in the contraction-relaxation process in myocytes. The calcium-induced permeability transition of the heart mitochondria inner membrane appears to be an important calcium efflux mechanism involved in some physiological and pathological situations. The negative inotropic effect of the anaesthetic propofol results in part from a decrease in intracellular calcium availability. Thus, this study evaluates the effects of propofol on calcium transport and permeability transition of heart mitochondria. The propofol-inhibition of the permeability transition of liver mitochondria was previously investigated [Eriksson, O. (1991) FEBS Lett. 279, 45-48] in such conditions that its uncoupling effect was not taken into account. We show here that propofol uncoupling results in a decrease in calcium uptake rate which could in part explain the decreased permeability transition rate. However, comparison of equipotent uncoupling concentrations of propofol and carbonylcyanide m-chlorophenylhydrazone reveals that beyond this uncoupling effect, propofol has a direct inhibitory action on the permeability transition pore, concomittant with a shift of its gating potential.

Mitochondrial energy metabolism in brain-dead organ donors.

OBJECTIVES: Change from aerobic to anaerobic metabolism has been described in brain-dead organ donors (BDOD) managed for organ procurement. Such modifications could lead to a depletion in intracellular adenine nucleotides and in part explain primary graft dysfunction. The purpose of this study was to investigate the mitochondrial energy metabolism in BDOD using permeabilized muscle fibers. METHODS: With institutional approval, the study was performed prospectively in 15 consecutive BDOD. In each patient, muscle biopsy and blood samples for the determination of plasma lactate and pyruvate were obtained just before organ removal. Mitochondrial respiratory parameters of skeletal muscle were determined in saponin-skinned muscle fibers. Mitochondrial oxygen consumption rates were measured polarographically using different substrates and inhibitors of the respiratory chain complexes. Results were compared to those obtained from muscle biopsies performed in 10 healthy patients during orthopedic surgery. RESULTS: Fifteen donors, 13 men and 2 women, aged 35 +/- 11 yrs, were studied. All patients had a high lactate-to-pyruvate ratio (10). Mitochondrial respiration rates were significantly decreased during adenosine triphosphate (ATP) synthesis. CONCLUSIONS: Major changes in energy metabolism occurred during brain death with a decrease in ATP synthesis capacity. High-risk donors should be recognized for a better graft evaluation.

[Indications and role of albumin for vascular loading in trauma patients and during preoperative period]. / Indications et place de l'albumine au cours du remplissage vasculaire en traumatologie et en période préopératoire.

The use of albumin solutions for volume replacement remains controversial. The last American guidelines recommend the use of albumin for resuscitation in case of a contra-indication of artificial colloids or the requirement of sodium restriction. Recent trials did not show any beneficial effect of albumin on the mortality and morbidity rates. Only an improvement of the rheologic conditions has been found with albumin (and dextran 40), in comparison with starch and gelatin. On the basis of cost-effectiveness considerations, artificial colloids should be at this time favoured over albumin for intravascular expansion, except in pregnant women. For resuscitation, albumin could be used when the recommended upper limit of hydroxyethyl starch vol-ume has been reached and fresh frozen plasma not yet required. During preoperative haemodilution, low molecular weight hydroxyethyl starch has at least the same efficacy as albumin. When a rheological effect is required, albumin could be used.

[Hemodynamic effects of hypertonic saline solutions]. / Effets hémodynamiques des solutions salées hypertoniques.

Haemodynamic effects of hypertonic saline solutions (HSS) have been extensively studied in animals and humans. Hypertonic sodium chloride (7.5%, 2,500 mOsm.L-1) either alone or combined with colloids, remains the standard solution. The haemodynamic response of HSS observed during treatment of hypovolaemic shock is explained by 1) an increase in preload due to the expansion of the plasma volume and a musculocutaneous vasoconstriction and 2) a decrease in systemic vascular resistance and afterload. A myocardial stimulation has been shown in various experimental conditions and in humans. However, the clinical relevance of this inotropic effect is questionable. Haemorrhagic shock is the main indication for small volume resuscitation with HSS. Other potential situations for the use of HSS are volume replacement in perioperative period, septic shock or burn injury and cardiopulmonary resuscitation. Before recommending the clinical use of HSS, additional clinical studies are required to substantiate the benefits of HSS over colloids.

[Traumatic diaphragmatic rupture with delayed unusual disclosure]. / Rupture diaphragmatique traumatique de révélation tardive inhabituelle.

The authors report the case of a delayed presentation of a traumatic diaphragmatic rupture in a 22-year-old patient admitted to hospital for a minor surgical procedure under general anaesthesia. Nine months before, he had a road traffic accident with a minor thoracic trauma. Three days after surgery, the patient was readmitted for a tension hydrothorax due to the herniation and the perforation of the stomach into the left pleural cavity. Such a delayed presentation of a traumatic diaphragmatic rupture remains uncommon. The peroperative ventilatory factors involved in the development of the hernia are discussed.