[Single-use laryngoscope blade assessment]. / Evaluation des lames de laryngoscopes à usage unique.

OBJECTIVES: To assess the feasibility of switching disposable laryngoscope blades and to compare the disposable blades available on the market to reusable blades within the context of a new variant of Creutzfeldt-Jakob disease. STUDY DESIGN: Comparative prospective study. MATERIAL AND METHODS: Study conducted on patients intubated for surgical procedures in all operating theatres of a university hospital. The anaesthetic practitioner filled in an assessment form giving a score on nine criteria for each blade used. Data were recorded on Epi Info software. Satisfaction scores of each criterion were compared for both disposable blades and reusable blades. RESULTS: Six brands of blades were tested with 225 blades. Disposable blades were evaluated as inferior to the reusable blades in 62% of cases. Two blades were reported as more satisfactory: the 670166 Rusch-Pilling and Vital View blades. CONCLUSION: The disposable blades were not easily accepted by the anaesthetists particularly for difficult intubations, which is why reusable blades should not be totally removed from practice. Single-use blades proposed by different manufacturers are not identical. We chose 670166 Rusch-Pilling blades, the best adapted to our institution. The switch to disposable blades would require that blade manufacturers improve the quality of the blades.

Inhaled nitric oxide: effects on hemodynamics, myocardial contractility, and regional blood flow in dogs with mechanically induced pulmonary artery hypertension.

BACKGROUND: Pulmonary artery hypertension with right ventricular failure is a frequent complication that occurs immediately after heart transplantation in which the use of inhaled nitric oxide may be effective. METHODS: The effects of pulmonary artery hypertension and nitric oxide on myocardial function and on pulmonary and systemic hemodynamic parameters were evaluated in eight anesthetized dogs. Pulmonary artery hypertension was induced by successive microbead injections into the pulmonary circulation. RESULTS: Microbead injections resulted in overt pulmonary artery hypertension (pulmonary artery pressure, + 190%; pulmonary vascular resistance, + 389%; ratio of pulmonary vascular resistance to systemic vascular resistance, 0.41). RESULTS: The end-diastolic length of the right ventricular outflow tract increased significantly along with an increase in right ventricular contractility (peak first derivative of left ventricular pressure as a function of time, + 100%; outflow tract systolic shortening, + 19%). Despite this compensatory mechanism, the increased pulmonary barrier resulted in a decrease in stroke volume (-31%). Systemic effects were observed, such as an increase in heart rate that maintained the cardiac output despite a decrease in left ventricular end-diastolic length (end-diastolic length in region of left anterior descending artery, - 9%). Right myocardial and septal blood flows were also significantly increased. CONCLUSIONS: Nitric oxide administration restored the stroke volume with a decrease in pulmonary artery hypertension and an improvement of the pulmonary vascular resistance to systemic vascular resistance ratio. Systemic blood pressure and coronary perfusion remained unaffected. This selective effect on the pulmonary circulation should be considered a major advantage of nitric oxide inhalation in the treatment of right ventricular dysfunction in acute pulmonary hypertension.

A computer program for automatic measurement of respiratory mechanics in artificially ventilated patients.

A program for automatic and periodic determination of respiratory mechanics in artificially ventilated patients is described. Airway pressure and flow signals are obtained from the ventilator in the controlled ventilation mode with constant flow inflation and end-inspiratory pause. Periodically, the program records both signals for a given time and it delimits a ventilatory cycle and its components out of this record. Then, four mechanical parameters of the respiratory system are calculated: (1) Rinit, the resistance obtained with the end-inflation occlusion technique; (2) Ers, the elastance (inspiratory) calculated from the slope of the airway pressure profile during inflation; (3) tau, the expiratory time constant; (4) PEEP, the global positive end expiratory pressure. All parameter measurements have been evaluated in experimental conditions, and are in good agreement with reference values. The complete software includes the display of the signals and of the trends together with automatic disk file backups. An additional program allows one to display the trends again and to create table text files containing all the recorded data for further analysis. The system proved to work in ICU and anaesthesia patients with various ventilators.

Comparison between acute hypoxia-induced and mechanically-induced pulmonary artery hypertension on the hemodynamics, myocardial contractility and regional blood flow in dogs.

Two groups of eight anesthetized dogs with pulmonary artery hypertension (PAH) were compared. PAH was induced by submitting one group (HP) to hypoxia (FiO2 range: 6-10%) and the other group (ME) to microemboli through glass microbead injection into the pulmonary circulation. Hypoxia-induced PAH was moderate (PAP: +65%; PVR: +152%) contrasting with marked PAH after microbead injection (PAP: +190%; PVR: +389%). For similar effects on left ventricular contractility (LV dP/dt max and segmental myocardial shortening), heart rate and systemic vascular resistance, left ventricular end-diastolic pressure showed significant differences between the two groups (HP group: +75%, ME group: -9%), and so did left ventricular end-diastolic length (HP: +9%, ME: -11%). Thus, contrary to the injection of microbeads, hypoxia did not give rise to any pulmonary barrier, and consequently the changes in cardiac output (HP: +19%, ME: -15%) and hepatic blood flow (HP: +383%, ME: -77%) were significantly different. Hypoxia, and not microbead injection, was responsible for systemic hypertension (MAP: +34% and -4%, respectively). The microbead model resulted in a significantly higher PVR/SVR ratio compared to the hypoxic model (HP: 0.14, ME: 0.41). Hypoxia increased left and right myocardial blood flows whereas microbead injection affected only right ventricular blood flow, leading to significantly different RV/LV endocardial perfusion ratios (HP: +10%, ME: +98%). We conclude that microbead-induced PAH is more appropriate than hypoxia-induced PAH for hemodynamic and pharmacological studies.

[Modes of use of central venous catheters in pediatric hematology]. / Modalités d'utilisation des cathéters veineux centraux en hématologie pédiatrique.

The authors have studied a population of 51 children in which 63 central venous catheters were used for the treatment of leukemias, solid tumors and lymphomas. Two groups were isolated: continuous hospitalization (group A) and intermittent hospitalization with periodical day care (group B). Mean duration of catheterization was 129 days in group A and 176 days in group B (whole population: 149 days), with a total of 9,724 days of catheterization. There was no significant differences between the two groups concerning infection, bleeding, thrombosis or migration. So the authors believe that permanent hospitalization is not mandatory for chemotherapy in children with severe malignant diseases. Periodical day care therapy allows a near normal life for children and a better cooperation from their parents.

[Prevention of per- and postoperative myocardial ischemia in non-cardiac surgery by intravenous diltiazem]. / Prévention de l'ischémie myocardique per- et postopératoire en chirurgie non cardiaque par le diltiazem intraveineux.

A controlled double-blind trial was carried out to assess the efficacy and safety of a continuous intravenous infusion of diltiazem in preventing perioperative myocardial ischaemia in patients with coronary artery disease. Sixty-six patients undergoing non cardiac surgical procedures (vascular surgery, n = 37; other, n = 29) were randomly chosen to receive either diltiazem (group D, n = 32); or placebo (group P, n = 34); there was no difference between these groups in the number of patients in each NYHA class (I: 13/16; II: 14/14; III: 5/4) or having had a previous myocardial infarct (20/22). ECG leads CM5 and CL5 were recorded continuously with an ICR 7200 Holter monitor. After starting recording, either placebo or a loading dose (0.5 mg.kg-1) of diltiazem was given, followed by an infusion of 5 micrograms.kg-1.min-1. Anaesthesia was induced by thiopentone and suxamethonium, and maintained with nitrous oxide (50%), fentanyl and either halothane or droperidol. The number of myocardial ischaemic episodes was significantly (p less than 0.05) lower in group D (2 ST depressions in two patients) than in group P (8 ST depressions in six patients, 2 myocardial infarcts and 1 pulmonary oedema). No conduction disturbance was observed; the lowest cardiac frequency was found in group P (32 b.min-1). Systolic and diastolic arterial blood pressures were lower in group D than in group P, but no difference was found in heart rate and rate-pressure product.(ABSTRACT TRUNCATED AT 250 WORDS)

[Consumption coagulopathies following peritoneojugular bypass. Prevention by a heparin-antithrombin III combination]. / Les coagulopathies de consommation après dérivations péritonéo-jugulaires. Prévention par l'association héparine-antithrombine III.

Consumption coagulopathy (CIVD) is a frequent complication of peritoneojugular bypass operation. Preventive treatment applied involves low-dose heparin (1.5 mg/kg/d) to maintain an antithrombin III concentration of at least 65%. Results are evaluated in 6 patients treated by 7 bypass operations. A biologic CIVD developed in 2 cases (29%) but no clinical coagulopathy was observed. This incidence is less than that usually reported, a literature review indicating a biologic coagulopathy in 65% of cases, with clinical evidence in 12.5%. Furthermore, patients with spontaneously elevated AT III levels did not develop CIVD while, in contrast, sufficiently high concentrations of AT III could not be maintained in the 2 patients with coagulopathy. These findings suggest the interest of prevention of a CIVD by the use of this procedure.

[Acute thrombosis of the aortic bifurcation caused by heparin allergy. Apropos of 5 cases]. / Les thromboses aiguës du carrefour aortique par allergie à l'héparine. A propos de 5 observations.

Five patients with humoral intolerance to heparin developed acute thromboses, with a fatal outcome in two cases from failure to establish the diagnosis, marked sequelae in one case, and recovery without complications in the other two. Accidents of this type may occur in 0.6 p. cent of patients on heparin therapy and are almost always fatal if administration is not discontinued. They result from a severe immunoallergic. Thrombocytopenia which may lead to the formation of arterial clots. Arterial thrombosis during heparin therapy is suggestive of the diagnosis and tests for diminished platelet counts are necessary. Apart from surgery, treatment involves the immediate cessation of heparin therapy.

[Fentanyl-oxygen-pancuronium anaesthesia in cardiac surgery (author's transl)]. / Anesthésie au fentanyl-oxygène-pancuronium en chirurgie cardiaque.

A retrospective study of the anaesthetic records in cardiac surgical patients was undertaken: massive doses of fentanyl were used according to Stanley (29). The rate of drug administration was fentanyl 150 micrograms/kg for induction and 15 to 25 micrograms/kg/hour for maintenance, pancuronium bromide 0,1 mg/kg for induction and 0,015 mg/kg/hour for maintenance. Myocardial oxygen consumption (estimated by rate-pressure-product) during induction period remains constant. The oesophago-rectal temperature gradient is smaller than with other anaesthetic techniques, showing a very good perfusion homogeneity without the need of vasodilatator drugs. The temperature after-drop in the post bypass period is also reduced (less than 1,2 degrees C). The incidence of hemodynamic and rhythmic disturbances during operations and during the first post-operative day is lowered. Delayed respiratory autonomy appears to be the major drawback of this method (group 1: 25,30 h +/- 7,30 h; 30,20 h +/- 12,25 h; group 3: 21,15 h +/- 6,25 h).