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Biomedical subjects

C Ecoffey

Publications and source records attributed to C Ecoffey.

151 records · Page 9Linked to original sources
PubMed1984

Oxygen drive to breathing during halothane anesthesia: effects of almitrine bismesilate.

The changes in ventilation and breathing pattern induced by the substitution of pure oxygen for room air were tested in patients during stable halothane anesthesia before and after the administration of almitrine bismesilate, a specific stimulant of the peripheral chemoreceptors. Ventilation was monitored in 25 patients for 15 min while breathing an air-halothane (1.5%) mixture and while breathing then for 10 min an O2-halothane (1.5%) mixture. The maneuver was repeated in 11 of these patients after the infusion of 0.5 mg/kg of almitrine bismesilate. Before almitrine administration, O2 inhalation caused a progressive decrease of minute-ventilation (VE) reaching 94.5 +/- 1.4% (mean +/- SEM) of the initial value at the tenth minute (P less than 0.01). This decrease was secondary to a progressive increase of inspiratory and expiratory times. Almitrine bismesilate caused a significant increase in VE (+11.6%), tidal volume (+14.0%), and mean inspiratory flow (+10.0%) when breathing the air-halothane mixture. Ten minutes after O2 administration, these variables were not different from those observed before almitrine infusion. This study shows that during halothane anesthesia, hypoxic ventilatory drive is not abolished but is depressed severely. Almitrine bismesilate can restore the hypoxic ventilatory drive.

Adult↗
PubMed1984

Antidiuretic hormone response to osmotic stimulus under fentanyl anaesthesia.

The effect of fentanyl anaesthesia on the plasma antidiuretic hormone (ADH) response to osmotic stimulus was studied in eight patients. Eight g (137 mmol) NaCl were rapidly injected intravenously the day before anaesthesia and blood samples were collected 5, 10, 20 and 30 min after the injection. This protocol was repeated in the same subjects, under anaesthesia with thiopental, nitrous oxide and fentanyl before surgical incision. Plasma ADH markedly increased after NaCl administration and was significantly correlated with plasma sodium (r = 0.67, P less than 0.005) when the patients were awake, whereas it did not change over 30 min and was not correlated with plasma sodium (r = 0.18, P greater than 0.05) under fentanyl anaesthesia. This inhibitory effect of anaesthesia occurred in spite of a significant fall in the mean arterial pressure during the study. In order to eliminate the role of overnight fasting, premedication and fluid load, the same protocol was performed in six control patients who were fasted overnight, premedicated and fluid loaded. These results demonstrate that fentanyl anaesthesia abolishes the plasma ADH response to both osmotic and low arterial pressure stimuli.

Adult↗
PubMed1984

Impact of changes in operating pressure during high-frequency jet ventilation.

Fifteen critically ill patients with acute respiratory failure were ventilated with high-frequency jet ventilation (HFJV; frequency 100 breaths/min; I/E ratio 0.43; 1.8-mm internal diameter injector cannula). The patients were divided into two groups according to their initial PaO2 during intermittent positive pressure ventilation at FIO21: in eight patients (group I) the mean PaO2 was 141 +/- 34 mm Hg, and in seven patients (group II) mean PaO2 was 376 +/- 75 mm Hg. During HFJV three different operating pressures were used at random: 1.3, 1.8, and 2.3 bars. Increase in operating pressures significantly decreased PaCO2 and significantly increased mean lung volume above apneic FRC, mean airway pressure, and mean alveolar pressure in both groups. A close relationship was found between variations in mean airway pressure and mean alveolar pressure (r = 0.99, P less than 0.001). Significant increases in PaO2 with increasing operating pressures were observed only in group I. In group II, PaCO2 was significantly lower than in group I for a given operating pressure. We conclude that operating pressure is a main determinant of arterial oxygenation during HFJV because of the concomitant increases in intrathoracic pressures and lung volume. Operating pressure also influences carbon dioxide clearance, PaCO2 varies inversely with operating pressure.

Adult↗
PubMedDate not supplied

Infraclavicular block with lateral approach and nerve stimulation: extent of anesthesia and adverse effects.

BACKGROUND AND OBJECTIVES: The infraclavicular approach to the brachial plexus is little used despite theoretical advantages of the technique. Using a vertical paracoracoid approach, we assessed the extent of the sensory block and the incidence of adverse effects. METHODS: After obtaining informed consent, 100 patients undergoing surgical procedures distal to the elbow were evaluated. The block was performed using a peripheral nerve stimulator. The puncture site was located in the infraclavicular fossa; the direction of the insulated needle was perpendicular to the skin. Motor response was sought in the hand or wrist at < or = 0.6 mA. A total of 40 mL of 1.5% mepivacaine was administered as a single injection. The sensory block was evaluated every 5 minutes for 30 minutes before surgery in the cutaneous distribution of terminal branches of the brachial plexus. RESULTS: When one considers the cutaneous distributions of the median, ulnar, radial, and musculocutaneous nerves, the success rate was 89% for surgery without need for additional peripheral nerve blocks or general anesthesia. In contrast, cutaneous areas innervated by the axillary and medial cutaneous nerves were rarely anesthetized. We were unable to demonstrate a correlation between the intensity of the stimulation and the success of the block. On the other hand, a correlation was found between tourniquet sensation and the absence of anesthesia of the medial cutaneous nerve of the arm. Local anesthetic toxicity, Horner's syndrome, and vascular puncture were respectively observed in 1%, 4%, and 5% of cases. The depth of the needle introduction was correlated with the body mass index (P <.001; r =.63). CONCLUSION: Single injection infraclavicular block, using a vertical paracoracoid approach, appears suitable for surgery distal to the elbow. Selective anesthesia of the medial cutaneous nerve is useful in improving tolerance of the tourniquet.

Anesthetics, Local↗
PubMedDate not supplied

[Effects of isoflurane administered during spontaneous ventilation in the child].

The respiratory and haemodynamic changes produced by three inspired concentrations of isoflurane (1, 1.5, and 2%) were evaluated in a healthy children (mean age 4 yrs) breathing spontaneously during anaesthesia. Isoflurane produced respiratory depression; end tidal carbon dioxide tension increased from 38.8 +/- 3.6 mmHg at 1%, to 42.6 +/- 4.3 mmHg and 48.8 +/- 4.9 mmHg at 1.5 and 2% respectively. Respiratory frequency was not modified at the different inspired concentrations of isoflurane. Heart rate and arterial pressure decreased after induction of anaesthesia with isoflurane and remained at the same level throughout the study.

Anesthesia, Inhalation↗