[Monitoring of neuromuscular block by acceleromyography: concepts, applications and limits of use]. / Surveillance du bloc neuromusculaire par accéléromyographie : concepts, applications et limites d'utilisation.

A recent survey among French anesthesiologists revealed that monitoring of curarization is used in approximately in 50% of cases after a unique dose of curare and in 75% of cases after repeated doses of curare. In this survey, a majority of clinicians used a quantitative monitor based on acceleromyography, i.e. that the majority of clinicians used a device from the TOF-watch(®) product line. Results obtained by these monitors depends on the model used, TOF-Watch(®), TOF-Watch S(®) or TOF-Watch SX(®), as well as if it is used for a single point measurement at the end of the operation or continuously throughout the operation, with or without calibration, and if a calibration is used, should we used Cal 1 or Cal 2? Technical specifications and their impact on results will be developed in this technical note. This will help clinicians to better interpret results obtained by TOF-watch(®) monitors in order to improve clinical decisions based on monitoring of neuromuscular transmission.

[Reporting of muscle relaxant effects in anaesthesia files concerning visceral surgery - a observational and multicenter study]. / Traçabilité de la gestion de l'utilisation des curares dans le dossier d'anesthésie en chirurgie viscérale : une étude observationnelle et multicentrique.

OBJECTIVES: To report any item documenting the peroperative muscle relaxant effects management in anaesthesia files issued from visceral surgery processes. TYPE OF STUDY: Prospective, observational and multicenter. PATIENTS AND METHODS: A single operator analysed 1453 files proposed by nine anaesthetists' teams. The items selected concerned three periods: induction/tracheal intubation, paralysis maintenance, tracheal extubation. Reporting of 40 categories of items was studied. RESULTS: Items related to laryngoscopy and intubation conditions were observed in 43% (0-95) [general average (intercentres min-max)] and in 11% (0-97) of the files, respectively. At least one level of paralysis was reported in 23% (0-96) of the files. For the paralysis maintenance, documentation of an effect appeared in 53% (4-96) of the documents. Neuromuscular assessments preceding the tracheal extubation were retrieved in 43% (12-89) of the notes. Adductor pollicis was concerned for 30% (1-89) of these observations. Detection of level of spontaneous paralysis offset, satisfying to the local standard, appeared in 14% (3-19) of the documents. Pharmacological reversal was noted for 25% (4-67) of the patients; the assessment of the effects so produced was reported in 8% (0-58). CONCLUSION: In the studied collection, the traceability of the peranaesthetic curarization management appears variable on both qualitative and quantitative levels. The emergence of a dedicated guideline - defining the criteria for producing a good documentation of the muscle relaxant use - becomes necessary to secure these practices for all physicians using muscle relaxants.

[Medicamentous bezoar following pancreaticoduodenectomy: the combined use of cholestyramine and antisecretory medications as a risk factor in pancreatic surgery]. / Pharmaco-bézoar après duodénopancréatectomie céphalique, association Choléstyramine + antisécrétoires: situation à risque en chirurgie pancréatique?

The authors describe a case of pharmaco-bezoar consisting of ingested cholestyramine which occurred post pancreaticoduodenectomy. Intestinal obstruction by a cholestyramine bezoar is a rare occurrence but is worthy of note in the post-pancreatectomy setting where there is often concomitant use of cholestyramine, proton pump inhibitors, and octreotide.

[Prevention of venous thromboembolism following cardiac, vascular or thoracic surgery]. / Prévention de la maladie thromboembolique veineuse périopératoire en chirurgie cardiaque, vasculaire et thoracique.

In the absence of thromboprophylaxis, coronary artery bypass graft surgery (CABG), intrathoracic surgery (thoracotomy or video-assisted thoracoscopy), abdominal aortic surgery and infrainguinal vascular surgery are high-risk surgeries for the development of venous thromboembolic events (VTE). The incidence of VTE following surgery of the intrathoracic aorta, carotid endarterectomy or mediastinoscopy is unknown. Data from the litterature are lacking to draw evidence-based recommandations for venous thromboprophylaxis after these three types of surgeries, and the following guidelines are but experts'opinions (Grade D recommendations). Thromboprophylaxis is recommended after CABG (Grade D), with either subcutaneous (SC) low molecular weight heparin (LMWH) or SC or intravenous (i.v.) unfractioned heparin (UH) (PTT target = 1.1-1.5 time control value) (both grade D). This may be combined with the use of intermittent pneumatic compression device (Grade B). After valve surgery. The anticoagulation recommended to prevent valve thrombosis is sufficient in order to prevent VTE. We recommend thromboprophylaxis with either LMWH or low dose UH to prevent VTE after aortic or lower limbs infrainguinal vascular surgery (both grade B and D). Vitamine K antagonists (VKA) are not recommended in this indication (Grade D). We recommend thromprophylaxis following intrathoracic surgery via thoracotomy or videoassisted thoracoscopy (grade C). Either subcutaneous LMWH or subcutaneous or i.v. low dose UH may be used (Grade C). Efficacy of intermittent pneumatic compression device has been demonstrated in a study (grade C). VKA are not recommended (grade D). No further recommendation regarding the duration of thromboprophylaxis after these three types of surgeries can be made.

Upper limb ischemia after subclavian flap aortoplasty: unusual long-term complication.

Repair of isolated coarctation of the aorta by subclavian flap aortoplasty carries the disadvantage of impaired blood supply to the left arm. However, ligation of branches of the subclavian artery can be tolerated without manifest ischemia of the upper extremity. We report the case of a young man who suffered from left upper extremity ischemia 18 years after initial operation. Treatment consisted of carotid-subclavian bypass with good outcome. The surgical approach of coarctation by subclavian aortoplasty should be reserved for specific cases, and if this procedure is performed, ligation of branches of the subclavian artery should be minimized to increase inflow into the left brachial artery.

Continuous infusion of remifentanil and target-controlled infusion of propofol for patients undergoing cardiac surgery: a new approach for scheduled early extubation.

OBJECTIVE: To assess hemodynamic stability, postoperative pain management, and the control and timing of early extubation of a total intravenous anesthetic technique using propofol target-controlled infusion (TCI) and remifentanil in cardiac surgery. DESIGN: Prospective study. SETTING: University hospital. PARTICIPANTS: Fifty patients scheduled for elective cardiac surgery. INTERVENTIONS: Premedication consisted of oral midazolam, 0.1 mg/kg. Anesthesia was induced with propofol TCI at a target concentration of 1.5 to 2 microg/mL; remifentanil, 1 microg/kg; and rocuronium. Anesthesia was maintained with propofol at the same target concentration and remifentanil titrated between 0.25 and 1 microg/kg/min. Thirty minutes before the end of surgery, a 0.1-mg/kg bolus of morphine was administered intravenously. Postoperative sedation was achieved by maintaining the propofol infusion until the patient was deemed ready for extubation. Postoperative pain relief was evaluated using a visual analog scale. The intervals between arrival in the intensive care unit, spontaneous ventilation, and extubation were recorded. MEASUREMENTS AND MAIN RESULTS: Included in this study were 36 men and 14 women (American Society of Anesthesiologist = III; New York Heart Association = II) scheduled for cardiac surgery. All patients remained hemodynamically stable throughout the perioperative period. Thirty-seven patients were successfully extubated during the first 4 postoperative hours. Spontaneous breathing was achieved at a mean interval of 15+/-5 minutes after propofol discontinuation. The mean interval to extubation was 163+/-45 minutes after arrival in the intensive care unit. Extubation was performed 48+/-12 minutes after patients were considered ready to awaken. During spontaneous ventilation, 36 patients received additional boluses of morphine (mean, 2.5+/-1 mg). Subsequently, all patients achieved a visual analog scale less than 40 mm. CONCLUSION: The combination of remifentanil and propofol TCI resulted in hemodynamic stability and good postoperative analgesia. This technique allows physicians to schedule the time of extubation in patients undergoing cardiac anesthesia.

Does aprotinin modify the effects of ischaemia-reperfusion on the myocardial performance of a blood perfused isolated rabbit heart?

Aprotinin has been reported to influence positively or negatively the process of ischaemia-reperfusion. However, it is a complex drug acting on platelets, neutrophils and coagulation, which may also have a direct effect by inhibiting intracellular proteases and free radical generation. The goal of this study was to determine the direct effects of aprotinin on the myocardial performances of an isolated blood perfused rabbit heart preparation after normothermic global ischaemia. Two groups of 10 hearts were studied. The control group (ischaemia) underwent 30 min of global normothermic ischaemia. In the aprotinin group, (aprotinin) 200 KUI mL-1 of aprotinin was added to the perfusate before ischaemia. Measurements were obtained at base-line, 10, 30 and 60 min after reperfusion. Normothermic ischaemia significantly decreased myocardial performance in both groups. After 60 min reperfusion, myocardial contractility significantly recovered in the aprotinin group compared with the ischaemia group. Aprotinin contributes significantly by limiting the consequences of ischaemia on myocardial performances. This effect may be due to a direct action of the drug because leucocytes and plasma proteins were removed in this preparation.

Comparison of the acute hemodynamic effects of hypertonic or colloid infusions immediately after mitral valve repair.

OBJECTIVE: To determine the acute hemodynamic effect of hypertonic saline and/or colloid solutions as volume resuscitation in postoperative mitral valve repair patients. DESIGN: Prospective, randomized trial. SETTING: Postoperative cardiac intensive care unit of Broussais Hospital. PATIENTS: Twenty-six patients who underwent mitral valve repair were prospectively studied. Two patients were excluded during the study. INTERVENTIONS: During the immediate postoperative period, when wedge pressure decreases to <8 mm Hg, patients were randomly assigned to receive 250 mL of either hypertonic saline 7.2%-hydroxyethyl starch 6% (molecular weight, 200,000; hydroxyethylation ratio, 0.5) solution (HS-HES group), hypertonic saline 7.2% solution (HS group), or hydroxyethyl starch 6% solution (HES group). The infusion was completed within 15 mins. No additional volume was infused throughout the study. MEASUREMENTS AND MAIN RESULTS: Standard hemodynamic measurements and echocardiographic data demonstrated that HS-HES and HS induced a higher increase in left ventricular end-diastolic area than HES. In the HS-HES and HS groups, systemic vascular resistances decreased significantly and end-systolic area tended to decrease. In the HES group, systemic vascular resistances did not change and end-systolic area tended to increase. Accordingly, ejection fraction increased significantly by 21% and 18% with HS-HES (from 50.5 +/- 5.5 to 61.2 +/- 4.8) and HS (from 49.7 +/- 3.6 to 58.8 +/- 3.3), respectively, and did not change with HES. A major increase in cardiac index was observed after hypertonic solutions infusion, from 2.9 +/- 0.3 to 4.1 +/- 0.4 L/min/m2 in the HS-HES group and from 2.7 +/- 0.3 to 3.8 +/- 0.4 L/min/m2 in the HS group. Then, cardiac index progressively returned to baseline values within the 3 hrs after the infusion. No significant difference was observed between HS-HES and HS. In these groups, plasma sodium increased significantly after the infusion and remained higher than baseline values throughout the study. Adverse events were observed only with hypertonic solution administration: hypotensive episodes, sudden increases in pulmonary capillary wedge pressure, and ventricular arrhythmias. These side effects are likely attributable to a too-high dose and/or rate of infusion. All patients included in the study were discharged from the hospital before the 10th postoperative day. CONCLUSION: We conclude that in patients who have undergone mitral valve repair, postoperative infusion of hypertonic saline solutions increases left ventricular preload and left ventricular ejection fraction. The use of these hypertonic solutions may be of interest in patients with valvular cardiomyopathy. A titrated dose and a low rate of infusion may substantially improve the safety.

Continuous infusion versus bolus administration of sufentanil and midazolam for mitral valve surgery.

OBJECTIVE: In the present study, the authors compared continuous infusion to bolus administration of sufentanil and midazolam in patients undergoing mitral valve surgery. The purpose of the study was to evaluate the hemodynamic variability, total dose, effective plasma drug concentrations, and simplicity of the two anesthetic techniques. DESIGN: Prospective, randomized study. SETTING: University hospital. PARTICIPANTS: Thirty patients scheduled for elective mitral valve surgery. INTERVENTIONS: Induction of anesthesia was similar in both groups and consisted of sufentanil, up to 2 microg/kg, and midazolam, 0.05 to 0.15 mg/kg, followed by atracurium, 0.5 mg/kg. Anesthesia was maintained in the bolus group with predetermined boluses of sufentanil, 2 microg/kg, and midazolam, 0.03 mg/kg. Boluses were not administered if blood pressure was within 20% of baseline. The continuous-infusion group received sufentanil, 3.6 microg/kg/h, and midazolam, 0.08 mg/kg/h, started immediately after induction. The infusion rate was reduced to sufentanil, 1.8 microg/kg/h, and midazolam, 0.04 mg/kg/h, after sternotomy and was discontinued at skin closure. Atracurium was infused at a rate of 0.5 mg/kg/h up to sternal closure in both groups. No inhalation agents were used. MEASUREMENTS AND MAIN RESULTS: Hemodynamic variability between the groups was not significant. Total sufentanil dose was 773 +/- 186 microg in the continuous-infusion group and 610 +/- 184 microg in the bolus group (p = 0.01). Total midazolam dose was 14.4 +/- 3 mg and 11.2 +/- 3 mg in the continuous-infusion and bolus groups, respectively. There were 3.46 (range, 0 to 7) additional bolus injections in the bolus group and 0.31 (range, 0 to 1) in the continuous-infusion group (p < 0.001). Plasma sufentanil concentrations at extubation were similar in both groups (0.5 ng/mL). Plasma midazolam concentrations at extubation in the bolus group (17 +/- 6.7 ng/mL) were similar to those in the continuous-infusion group (23 +/- 5 ng/mL). CONCLUSION: The simplicity of the continuous infusion is a major advantage. This technique provides hemodynamically safe and stable conditions similar to those of bolus administration.

[Dynamic left intraventricular obstruction after reconstructive mitral valve surgery]. / Obstruction dynamique intraventriculaire gauche après chirurgie réparatrice valvulaire mitrale.

A 71-years-old patient, undergoing mitral valve repair for degenerative valvulopathy and correction of pectus excavatus experienced a cardiogenic shock after weaning from cardiopulmonary bypass. The shock occurred after calcium chloride administration and was unresponsive to inotropic drugs. Transoesophageal echocardiography showed left ventricular outflow tract obstruction due to systolic anterior motion (SAM) of the mitral valve. Discontinuation of inotropic drugs and volume expansion restored the haemodynamic status. By its haemodynamic effects calcium chloride can cause left ventricular outflow tract obstruction, recognized by transoesophageal echocardiography.

Comparative study of different biological glues in an experimental model of surgical bleeding in anesthetized rats: platelet-rich and -poor plasma-based glue with and without aprotinin versus commercial fibrinogen-based glue.

The use of fibrin glue in cardiovascular surgery has been associated with decreased operative time, effective control of localized bleeding, and reduced postoperative blood loss. All preparations of fibrin glue mimic the final common pathway of the coagulation cascade in which fibrinogen is converted to fibrin in the presence of thrombin and calcium. The goal of the study was to compare five different types of fibrin glue, with or without aprotinin, on a surgical bleeding model in the rat. In 70 anesthetized Wistar rats, after laparotomy, a 3 cm liver incision was performed. After randomization, seven groups were studied. In the first group, Biocol was used as a pinpoint application to the bleeding site. Four groups received a fibrin glue obtained from a single human donor plasma using Cell Saver V (Haemonetics). The sealant was applied as a two-component system. The first component of the glue was either platelet-rich-plasma (PRP) or platelet-poor-plasma (PPP). The second component consisted of a mixture of 0.5 ml CaCl 10% with 1000 U of human thrombin, with or without 400KUI of aprotinin (AP). The last two groups, control and aprotinin were treated using saline solution or topical aprotinin respectively. Hemoglobin and hematocrit were measured before surgery and 30 min after application of the glue. The decrease in hemoglobin (Hb) and hematocrit (Hct) was the primary efficacy variable. Before surgery, there was no difference regarding Hb and Hct values between groups. Thirty min after the application of the glue, the decrease in hemoglobin expressed as percent of the control values is only significantly lower in the Biocol group when compared to control. No significant difference was observed with the other groups in comparison to control. The commercial fibrin glue (Biocol) is more efficient than other preparations. This efficacy is likely due to a higher fibrinogen concentration.

[Assessment of cardiovascular perioperative risk in non-cardiac surgery]. / Evaluation du risque cardiovasculaire périopératoire en chirurgie non cardiaque.

Patients with cardiovascular disease undergoing non cardiac surgery are exposed to three cardiac risks: myocardial infarction, heart failure and death. To estimate cardiac risk, clinical predictors of perioperative cardiovascular risk are classified as major, intermediate and minor and non cardiac surgery is stratified in high risk (greater than 5%), intermediate (from 1 to 5%), minor (lower than 1%) procedures. Efficient perioperative assessment of cardiac patients is obtained by teamwork and usually, indications for further cardiac investigations are the same as those in the nonoperative setting. An simplified algorithm, easier to use than original algorithm given in the guidelines of the American college of cardiology and the American heart association, may be helpful for the indication of further investigations. Five questions must be answered before using algorithm: is it an emergency surgical procedure?, was a coronary revascularization required in the past five years? has the patient had a coronary evaluation in the past two years?, are there identified clinical predictors of cardiac risk?, is it major or minor surgery? Three tests evaluate the preoperative cardiac risk: exercise testing, dipyridamole thallium scintigraphy, dobutamine stress echocardiography. Their accuracy is similar, their negative predictive value is high, their positive predictive value is low. These guidelines may be helpful to indicate further cardiac investigations which will have an impact on patient's treatment, monitoring during or after surgery and outcome.

Tris-hydroxymethyl aminomethane and sodium bicarbonate to buffer metabolic acidosis in an isolated heart model.

Metabolic acidosis induces a decrease in the developed force of cardiac muscle by affecting every step of the excitation--contraction coupling pathway. Due to transient worsening in intracellular acidosis, the value of administering sodium bicarbonate therapeutically during acute acidosis has been questioned. An alternative therapeutic drug, Tris-hydroxymethyl aminomethane (THAM) has the advantage of diffusing into the intracellular space. This study was designed to evaluate the effects of metabolic acidosis on myocardial performance and to determine the effects of alkalinization with sodium bicarbonate, THAM, and their combination. Using a blood-perfused isolated heart preparation, left ventricular contractility and relaxation were measured at normal pH and during metabolic acidosis (pH = 7.0). Acidosis dramatically impaired myocardial contractility and relaxation. After buffering with sodium bicarbonate, although plasma bicarbonate concentration was normalized, pH remained below normal owing to an increased PaCO2. Contractility and relation were initially worsened, then slightly improved to return to control values. THAM uncompletely buffered acidosis but significantly improved contractility and relaxation. The combination of THAM with sodium bicarbonate perfectly buffered acidosis without modifying PaCO2 and significantly improved contractility. The combination of THAM with sodium bicarbonate is based on the ability of THAM to capture the CO2 produced by the sodium bicarbonate buffer. This combination achieves a perfect correction of metabolic acidosis and improves myocardial performance.