Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Jan 1976
Jet ventilation for fiberoptic bronchoscopy under general anesthesia.
An oxygen jet method ventilating patients during laryngoscopy has been applied to fiberoptic bronchoscopy. A 3.5 mm plastic tube 24.5 cm long was inserted into the trachea through the mouth. An intermittent jet of oxygen at 3.5 atm (50 psi) was applied to this tube using a 1.5 mm ID plastic catheter to ventilate the patient. ⋯ The high PO2 levels were maintained even during suctioning. General anesthesia for fiberoptic bronchoscopy can be performed using an endotracheal tube not smaller than 8 mm internal diameter (ID). The advantages of the oxygen jet technique are that it can be used in smaller patients and that the upper airway can be examined.
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Acta Anaesthesiol Scand · Jan 1976
Breathing mechanics, dead space and gas exchange in the extremely obese, breathing spontaneously and during anaesthesia with intermittent positive pressure ventilation.
Breathing mechanics and gas exchange were studied in 10 extremely obese subjects (average weight 138 kg) prior to and during anaesthesia with mechanical ventilation. Breathing mechanics were analysed from measurements of transpulmonary pressure (during anaesthesia, trans-chest wall pressure as well) inspiratory gas flow and tidal volume. Gas exchange was studied by analysing inspired and from the Bohr equation, and the division into anatomical and alveolar dead space was arrived at by capnography. ⋯ A moderate hypoxaemia was recorded during spontaneous breathing, and the alveolar-arterial oxygen tension difference was slightly elevated. During anaesthesia this difference was markedly greater. It is concluded that the most probable reason for the relative hypoxaemia is right-to-left shunting.
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Acta Anaesthesiol Scand · Jan 1976
ReviewThe effect of respiratory frequency on pulmonary function during artificial ventilation. A review.
This is a review of previous studies on the effects of variations between 12 and 24 breaths per minute in ventilation frequency during artificial ventilation, minute ventilation being constant. The total material consisted of 66 healthy subjects investigated under anaesthesia with artificial ventilation and 43 patients investigated during prolonged respiratory treatment. An increase in ventilation frequency resulted in an increased ratio of dead space to tidal volume (VD/VT) and in diminished alveolar ventilation with a subsequent elevation of Paco2. ⋯ Cardiac output was increased, as was venous admixture. Pao2 was slightly reduced. The more efficient gas exchange occurring at a low ventilation frequency makes this setting preferable in the treatment of patients with chronic obstructive lung disease, whereas a high ventilation frequency, by improving cardiac output, may be advantageous in patients with circulatory failure.
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Acta Anaesthesiol Scand · Jan 1976
Anesthesia for cesarean section III: effects of epidural analgesia on the respiratory adaptation of the newborn in elective cesarean section.
A rise in fetal Paco2 was observed after elective cesarean section in patients anesthetized both with a barbiturate and with nitrous oxide/oxygen. Epidural analgesia seemed to be a good alternative in order to attain better blood gas values in the newborn infant. Fourteen healthy mothers and their infants were studied in connection with elective cesarean section. ⋯ Maternal blood pressure falls were observed in four cases, and fetal effects could be detected. Although epidural analgesia has a more favorable effect upon the newborn's metabolic component, both the compared methods allow good respiratory adaptation provided they are used correctly. Mothers can be given the opportunity to choose between being conscious or asleep when their child is delivered.
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Acta Anaesthesiol Scand · Jan 1976
Anesthesia for cesarean section IV: placental transfer and neonatal elimination of bupivacaine following epidural analgesia for elective cesarean section.
Epidural analgesia with bupivacaine was used for elective cesarean section, and repeated maternal and neonatal blood samples were collected over 24 h for calculation of drug concentration. A gas-chromatogrphic micro-method was used for the analysis. The aim of this investigation was to evaluate the placental transfer and the elimination rate of the drug. ⋯ The fetal-maternal ratio of concentrations at delivery was higher than in previous studies, most probably due to the protein-binding characteristics of bupivacaine and the dosage used. The biological half-life of the rapid phase of elimination (alpha-phase) in the newborn was shorter than in the mother (P less than 0.002), indicating a more rapid distribution process. The half-life of the slow phase of elimination (beta-phase) in the newborn was of the same magnitude as in the mother, indicating that neonatal elimination processes of bupivacaine may be well developed at birth.