Haemodynamic effects of moderate normovolaemic haemodilution in conscious and anaesthetized patients.

We have assessed the haemodynamic effects of moderate normovolaemic haemodilution in ASA I patients, either conscious or during enflurane-fentanyl anaesthesia (10 patients in each group). Cardiac index (CI), stroke index (SI) and ejection fraction (EF) were measured by transthoracic electrical bioimpedance and, in the anaesthesia group, arterial and central venous blood samples were obtained to assess oxygen delivery (DO2), oxygen consumption (VO2) and oxygen extraction ratio (O2ER). In conscious patients, heart rate (HR) remained unchanged as SI, EF and CI increased. When haemodilution was performed during anaesthesia, CI remained stable in spite of a slight increase in SI, as HR decreased. This produced a reduction in DO2 which was compensated for by an increase in O2ER, allowing maintenance of VO2 without alteration in blood lactate concentration.

[Evaluation of anesthetic activity in the operating room. Use of beta relative cost index]. / Evaluation de l'activité anesthésique au bloc opératoire. Utilisation de l'ICR bêta.

OBJECTIVE: To evaluate the anaesthetic activity in the operating rooms using the newly reconstructed RCI beta, or relative cost index beta, a specific tool for analysis of anaesthetic activity and the linked cost. STUDY DESIGN: Prospective multicentric survey. METHODS: All scheduled anaesthetic procedures performed in March 1995 were collected. RCI beta items were entered in a standardized data base. Gender, age group, time of admission to the operating room, time of incision, time of exit from the operating room, and the code number of the surgical or radiological procedure were added on request of the steering committee. RESULTS: Complete responses were obtained from 35 out of the 37 contacted departments. A total of 31,391 procedures were analysed. Only 14% of patients were of ASA class over 2. Anaesthetic practices were comparable between institutions. Only the incidence of special circumstances and techniques was higher in University hospitals. General anaesthesia was the most widely used technique (76.58%). A large proportion (19%) of anaesthetics were given for endoscopy and radiology. More than 87% of patients were monitored postoperatively in recovery areas. There was a lower correlation between the theoretical standard duration and median actual duration of the perioperative period than the operative period (r = 0.54 vs r = 0.81). DISCUSSION: Part of our activity could be described with RCI beta. The obtained data allow a comparison of anaesthetic activity in the operating rooms of different hospitals, departments and units. Further analysis of these data will also provide information about the types of surgical procedures and the level of global activity.

Hemodynamic effects of 0.375% versus 0.25% bupivacaine during cervical epidural anesthesia for hand surgery.

BACKGROUND AND OBJECTIVES: Cervical epidural anesthesia with 0.375% or 0.25% bupivacaine plus fentanyl is a reliable technique for surgical restoration of digital motion-after tourniquet release and rehabilitation. The study was designed to assess the hemodynamic effects of this technique in 11 ASA 1 patients. METHODS: The epidural catheter was introduced at the C7-T1 interspace on the day of operation. The volume of 0.375% bupivacaine necessary to block the brachial dermatomes was determined. The day after (day 1), every patient received epidurally the determined volume of 0.375% bupivacaine plus 1 microgram/kg fentanyl (group A). On day 2 the same volume of 0.25% bupivacaine plus 1 microgram/kg fentanyl (group B) was injected. For each patient one or several pairs of injection (A + B) were performed in relation with duration of rehabilitation. Cardiac index, stroke volume index, end diastolic index, ejection fraction, and systemic vascular resistance were studied by thoracic electrical bioimpedance. These parameters, mean arterial pressure and heart rate were recorded before and after injection. Sensory level was assessed by loss of cold sensation. RESULTS: Nineteen paired injections were performed. Mean volume of bupivacaine was 7.1 +/- 2 mL. The caudad sensory level was lower in group A: T7 (T3-L1) versus T6 (T2-T11) in group B. Hemodynamic variables were not different between the 2 groups. Mean arterial pressure cardiac index, heart rate, stroke volume index, and ejection fracture decreased slightly as end diastolic index remained unchanged and systemic vascular resistance increased slightly. No correlation was found between hemodynamic changes and spread of analgesia. CONCLUSIONS: Hemodynamic effects, in ASA 1 patients, are moderate and not dependent on the studied concentration of bupivacaine, indicating that a similar degree of sympathetic block is achieved with 0.375% and 0.25% bupivacaine.

Bronchoalveolar lavage for diagnosing bacterial pneumonia in mechanically ventilated patients.

To assess the usefulness of BAL in diagnosing bacterial pneumonia in mechanically ventilated patients, 80 BAL fluid samples obtained from 72 patients with lung infiltrates were studied using the following parameters: infected cell count (polymorphonuclear leukocytes or macrophages with intracellular organisms), microscopic examination of stained smears, and quantitative culture with the determination of the simplified bacterial index (SBI) and the predominant species index (PSI). Of the 80 BAL samples studied, 56 were performed under antibiotic therapy. Bacterial pneumonia was the final diagnosis in 28 cases. The SBI is the sum of the whole numbers of each bacterial concentration expressed as a common logarithm. The PSI is the whole number of the predominant microorganism's concentration expressed as a common logarithm. The discriminative value of each test was assessed using a receiver operating characteristic (ROC) curve, whereby the possibility of establishing a cutoff value used to discriminate between the presence or absence of pneumonia is evaluated. The percentage of infected cells was higher in the pneumonia group (8.8 +/- 18.1 versus 0.4 +/- 1.1%, p < 10(-3), but no cutoff value could be proposed. Under microscopic examination, the presence of bacteria was noted with a significantly greater frequency in the pneumonia group (sensitivity 67.8% and specificity 82.7%). A total of 58 BAL samples were positive when cultured. The SBI was significantly higher in the pneumonia group (6.5 +/- 2.9 versus 1.6 +/- 1.7, p < 10(-4).(ABSTRACT TRUNCATED AT 250 WORDS)

[Risk of secondary neuromuscular blockade after autotransfusion of blood drawn from the patient following curare administration]. / Risque de curarisation secondaire après autotransfusion de sang prélevé chez un patient curarisé.

A secondary neuromuscular blockade can occur after transfusion of autologous blood withdrawn after injection of muscle relaxants. In this study time course of muscle relaxation after transfusion of blood withdrawn before or after administration of atracurium (A) or vecuronium (V) was assessed. Forty adults undergoing haemorrhagic urologic surgery were included in the study. After induction of general anaesthesia and intubation of the trachea facilitated by local lidocaine, they were divided into 4 groups. In groups A1 and V1 the blood units were withdrawn before injection of atracurium 0.5 mg.kg-1 or vecuronium 0.1 mg.kg-1. In group A2 and V2 the blood units were withdrawn after administration of muscle relaxants. Haematocrit was decreased to 0.30. The last bolus of these muscle relaxant was injected 30 min before the end of surgical procedure. Autologous blood was transfused when train of four (T4R) recovered to 0.80. Electromyographic elicited responses to T4R stimulation were obtained every minute during the 4 first minutes after the beginning of transfusion (T1 to T4), thereafter every minute during the 5 first minutes after the end of transfusion (T5 to T9), and finally every 5 minutes for 10 minutes (T10 and T11). There was a secondary neuromuscular blockade in patients of groups A2 and V2. The intensity of blockade was more important after vecuronium than after atracurium (p < 0.01 from T2 to T11 between groups A2 and V2). In group A2, the T4R had not reached the control level at the end of the procedure (0.78 at T11 vs 0.80 at T0). These data emphasize the importance of withdrawing blood units before administration of muscle relaxants.(ABSTRACT TRUNCATED AT 250 WORDS)

[The Relative Complexity Index beta: value of each parameter]. / ICR bêta: valeur de chaque paramètre.

The French health policy PMSI project (Program for a Medical Information System) is mainly aimed at development of cost analysis based on diagnosis related groups. An indicator of the relative costs of anaesthetics, the relative complexity index (ICR beta), was defined as the result of a computation of different indexes of surgical and anaesthetic procedures such as duration, patients ASA status, degree of emergency, stay in the recovery room. The aims of this study were 1) to analyze relative part of each index in ICR beta value and in ICR beta variance and 2) to assess the value of ICR beta as a cost or a complexity index. The study included 14,435 anaesthetics analyzed with the Dunn and Clarks multiple linear regression. Mean ICR beta was 267.28. The duration of the procedure accounted for 46% of the ICR beta value and surgery for 25%. The anaesthesia and the recovery accounted for 15% of the ICR beta value, but only for 0.0341 and 0.0347 respectively of the ICR beta variance. The product of the surgical procedure index by the ASA status index accounted for 0.259 of the ICR beta variance and the duration index for 0.650. The comparison of homogeneous groups with regard to the surgical procedure shows that intravenous anaesthesia accounts for 12.4% of the ICR beta value, inhalational anaesthesia for 13.84%, but exceeds 15% for regional anaesthesia (44.5% for caudal anaesthesia). For appendectomies (n = 114) duration index is still an important parameter in ICR beta variance (delta R2 = 0.354) but equivalent to the emergency index (delta R2 = 0.363).(ABSTRACT TRUNCATED AT 250 WORDS)

[Sedation with propofol and fentanyl in patients under intensive care]. / Sédation avec propofol et fentanyl en soins intensifs.

This study investigated the efficacy of a constant rate infusion of propofol and fentanyl in thirty patients requiring artificial ventilation for more than 24 h. A loading dose, which differed according to the patient's age, was administered over a 30 min period: 2.5 mg.kg-1 for patients less than 50 (G1) (n = 9), 2 mg.kg-1 for patients between 50 and 60 years old (G2) (n = 9), and 1.5 mg.kg-1 for patients over 60 (G3) (n = 12). This was followed by an infusion of 3 mg.kg-1.h-1 in G1 and G2, and 2 mg.kg-1.h-1 in G3. A 1 microgram.kg-1.h-1 infusion of fentanyl was also given. The degree of sedation was assessed with the Ramsay scale before starting, after induction, and every four hours thereafter. When this proved to be insufficient, the dose of propofol was increased by 0.5 mg.kg-1.h-1 as well as that of fentanyl by 0.5 microgram.kg-1.h-1. Heart rate, mean arterial blood pressure, blood propofol, creatinine, transaminase and lipid levels, and urine output were measured before, during, and after the infusion. The blood propofol level increased during the infusion, being correlated to the doses given (r = 0.64, p less than 0.001). Sedation lasted 91.7 +/- 57.7 h. After stopping the infusion of propofol, mean recovery times were 7.5 +/- 5.9 min (G1), 11.4 +/- 11.4 min, and 14.4 +/- 13.5 min (G3) (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

[Nicardipine vs trinitrin for controlled hypotension in maxillo-facial surgery]. / Nicardipine vs trinitrine pour hypotension contrôlée en chirurgie maxillo-faciale.

In this study we examined perioperative blood losses during maxillo-facial surgery comparing 2 techniques for controlled hypotension using nitroglycerin (NTG) and nicardipine (NICAR). 37 ASA I and II patients electively scheduled for rhinoseptoplasties under general anaesthesia were randomly divided into 2 groups. General anaesthesia was induced with intravenous thiopental and vecuronium following a neuroleptanalgesia consisting of fentanyl (0.053 +/- 0.004 microgram.kg-1.min-1) IV and droperidol (1.98 +/- 0.35 microgram.kg-1.min-1) IV given in bolus doses. The patients were intubated and ventilated (N2O in O2) to maintain normocarbia. Controlled hypotension to maintain a mean arterial pressure (MAP) between 50 and 55 mmHg was induced using an IV infusion of NTG 6 micrograms.kg-1.min-1 in group I and NICAR 10 micrograms.kg-1.min-1 over 10 minutes followed by an infusion at 4 mg.kg-1.min-1 for group II. Measurements of heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), MAP using an automated blood-pressure cuff and end tidal carbon dioxide (ETCO2) were recorded prior to induction (PREIND), intraoperatively (PEROP) at 15, 30, 40 and 120 minutes post-induction, and at 15, 30 and 60 minutes postoperatively (POSTOP). Blood loss, graded as minimal or frank, was assessed by the surgeon during the operative period, post-extubation and 3 days postoperatively at dressing removal. The surgeon was unaware of the randomization schedule. Student's test was applied for statistical analysis of measured variables and Fisher's test for qualitative parameters. No statistically significant differences were noted between both groups with respect to demographic data, duration of surgery and total doses of anaesthetic agents (Table I).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of hydrophobic heat and moisture exchangers with heated humidifier during prolonged mechanical ventilation.

Inspired gases must be warmed and humidified during mechanical ventilation. In a prospective randomized study we compared the performance of a heated humidifier (HH) (Draegger Aquaport) and a heat and moisture exchanger (HME) (Pall Filter BB 2215). A total of 116 patients requiring mechanical ventilation (Servo 900 C Siemens) were enrolled into the study and were randomly assigned to 2 groups. Patients in group I were ventilated with a traditional breathing circuit with HH and patients in group II using a simplified circuit with HME. Pre-existing and hospital acquired atelectasis and pneumonia, occurrence of endotracheal tube (ET) occlusion and ventilatory parameters (respiratory rate, tidal volume) were studied. No statistical difference was found between groups for each parameter except the greater frequency of ET occlusions in the II group (0/61 vs 9/55) (p = 0.0008). Pall Filter (PF), a hydrophobic filter, humidifies the dry gases from the condensed water which is put down on the HME surfaces during cooling of saturated expired gases. This purely physical property is linked to the magnitude of the thermic gradient between the expired gases and the ambiant temperature. Performance impairment of PF in our study might be due to high ambiant temperature in the intensive care unit (usually around 28 degrees C) which reduces thermic gradient and water exchanges. We conclude that efficiency of PF may be weak in some conditions of ambiant temperature.

Brachial plexus block with bupivacaine: effects of added alpha-adrenergic agonists: comparison between clonidine and epinephrine.

The effects of clonidine and epinephrine, administered into the brachial plexus sheath, were evaluated in 60 patients who underwent surgery of the upper limb. All patients received 40 to 50 ml of 0.25% bupivacaine, injected into the brachial plexus sheath, using the supraclavicular technique. The patients were randomly allocated to two groups so that 30 patients received 150 micrograms clonidine hydrochloride (Group I), and 30 received 200 micrograms epinephrine (Group II). The quality and the duration of analgesia were assessed as well as the possible side-effects. The block produced with the addition of clonidine was longer (994.2 +/- 34.2 vs 728.3 +/- 35.8 min) and superior to that with epinephrine (P less than 0.001). No major side-effects were recorded. We conclude that the injection of clonidine into the brachial plexus sheath is an attractive alternative to epinephrine to prolong the duration of analgesia following upper limb surgery under conduction anaesthesia.

[Incidence and etiology of cardiac arrest occurring during the peroperative period and in the recovery room. Apropos of 102,468 anesthesia cases]. / Fréquence et cause des arrêts cardiaques peropératoires et en salle de réveil. A propos de 102,468 anesthésies.

This study reviewed retrospectively 186 cardiac arrests (CA) observed in a series of 102,468 anaesthetics, carried out in a University Hospital between 1983 and 1987. Among them 29 were partly or totally related to anaesthesia and 11 had a fatal outcome. On the other hand, 157 CA (144 deaths) were not related to anaesthesia. Mortality rate due to anaesthesia was therefore 1.1 per 10,000. The main causes of anaesthesia related CA were overdosage, with or without hypovolaemia (9 CA, 6 of which occurred under regional anaesthesia); hypoxaemia (6 CA, 5 of which occurred under regional anaesthesia) and multifactorial sudden cardiac arrest (n = 8). The other aetiologies were: myocardial ischaemia (n = 3); anaphylactic shock due to propanidid (n = 1); protamine accident (n = 1); ventricular arrhythmia due to hypokalemia (n = 1). Fourteen CA occurred during induction (2 deaths), 14 during maintenance (8 deaths), and one during recovery. Risk factors for CA included a high ASA class, and the type of anaesthesia: there were 8 CA for 12,981 regional anaesthetics, and 21 for 89,487 general anaesthetics (p = 0.017). Emergency and paediatric anaesthesia were not risk factors. Outcome was independent of ASA class, but was related to aetiology: hypoxaemia (5 out of 6 recovered) and overdose with or without hypovolaemia (7 out of 8 recovered) had favourable outcomes. Furthermore, outcome of CA due to regional anaesthesia was satisfactory (7/8 recovered) (p = 0.08, NS). Such an analysis of the causes of anaesthetic disasters and their rate of occurrence can lead to more effective prevention.

[Pharmacokinetics and changes in the physical properties of blood and urine after administration of dextran 60000]. / Pharmacocinétique et modifications des propriétés physiques du sang et des urines apès administration d'un dextran 60,000.

A study was carried out to assess the changes induced by an infusion of dextran, molecular weight 60,000 daltons, in blood and urine. Plasma and urine dextran and serum protein concentrations, haematocrit, blood and urine viscosities, and blood oncotic pressure were measured in 10 consecutive male patients. Fifteen min after administration of 20 ml dextran 1000 (Promit), they were each given 500 ml (30 g) dextran 60 (Hemodex) over 30 min for plasma volume expansion. The measurements were carried out at the end of the infusion, and then at regular intervals over a 48 h period. The highest dextran blood concentrations were found at the end of the infusion, decreasing thereafter with a distribution half-life of 1.83 +/- 0.64 h, and an elimination half-life of 25.5 +/- 7.6 h. Haematocrit values decreased by 12%, and serum protein concentrations by 9.5%, after the end of the infusion. These changes remained significant for 9 h; they were probably due to the dilution effect of 500 ml of dextran. Colloid osmotic pressure was not significantly altered (20.7 +/- 4.7 mmHg vs. 23.1 +/- 5.1 mmHg 48 h after the end of the infusion). The colloid osmotic pressure due to dextran 60 compensated for the fall in protein concentration. A decrease in blood viscosity was found at different shear rates, despite dextran 60 being highly viscous. This could also be explained by a dilution effect. The highest degree of urinary excretion occurred 30 min after the end of the infusion, and lasted for 3 h. Forty-five percent of the total dextran dose had been excreted by the 48th hour.(ABSTRACT TRUNCATED AT 250 WORDS)

[Does flumazenil, a benzodiazepine antagonist used during the anesthesia recovery period, have an anxiogenic effect?]. / Le flumazénil, antagoniste des benzodiazépines, utilisé lors du réveil anesthésique, a-t-il un effet anxiogène?

The goal of this study was to assess the degree of postoperative anxiety flumazenil might provide in patients when used to reverse the sedation induced by midazolam. Twenty-four patients, aged 18 to 60 yrs, and scheduled for elective orthopaedic surgery of the upper limb, were included in the study Regional anaesthesia (brachial plexus block) was carried out 20 min after the patient had been premedicated with 0.15 mg.kg-1 intramuscular midazolam. When the block was clinically complete, 0.12 mg.kg-1 midazolam was given intravenously. Sedation was maintained throughout surgery using 0.03 mg.kg-1 midazolam every quarter of an hour (mean total dose 0.206 mg.kg-1). At the end of the procedure, the patients were randomly allocated to one of two groups: A+, the patients were given 0.1 mg intravenous flumazenil repeated every min until the patient was fully awake (mean 4.5 +/- 2.6 micrograms.kg-1); and A-, the patients were allowed to recover spontaneously. A wakefulness, and a determination just before premedication (E1, P1, H1 respectively). The degree of recovery was assessed in both groups, and, when the value of the wakefulness test had returned to that of E1 (E2) (E2 = E1), P2 and H2 were carried out. There were no statistically significant differences between P1 and P2, and between H1 and H2, and this for either group of patients. So, the doses of flumazenil used, which awoke all the patients within 3 min, did not create any anxiety. In accordance with most of the recently published studies, flumazenil can be safely used to reverse benzodiazepine induced sedation.