British journal of anaesthesia
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A ventilator, of new design, is described which has been evaluated on a lung model and in animals. It is simple, versatile, inexpensive and easy to sterilize. A single breathing tube is used in which the respiratory gas is introduced near the patient's airway while a jet in a more distal part of the tube drives the respiratory gas into the patient's lungs. ⋯ It can be used for any age group with any desired respiratory gas, and is suitable for use in the operating theatre and the intensive care unit. As there are no valves in the breathing system, which is open to the atmosphere at all times, complicated systems for synchronizing the machine with spontaneous breathing are not required. PEEP, NEEP, CPAP and IMV are applied easily.
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Comparative Study
Manual jet ventilation v. high frequency jet ventilation during laser resection of tracheo-bronchial stenosis.
Manual jet ventilation (20 b.p.m.) and high frequency jet ventilation (300 b.p.m.) were compared during laser resection of tracheo-bronchial stenosis under general anaesthesia. Both methods provided similar blood-gas tensions at the 10th min of surgery in patients with tracheal stenosis. In patients with bronchial stenosis high frequency jet ventilation resulted in modest hypercarbia and manual jet ventilation appeared to be the preferred method in these particular patients.
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The effect of carrier gas composition on the output of six anaesthetic vaporizers was studied using oxygen, nitrous oxide, helium and argon as the carrier gases. Vaporizer output was measured with an MGA 200 mass spectrometer and a Riken refractometer and, in addition, the pressure decrease across each vaporizer was determined simultaneously. ⋯ The possible reasons for the changes in steady state output are discussed in relation to the construction of each vaporizer. The addition of nitrous oxide to the carrier gas produced changes of clinical significance only when the vaporizers were used at extreme dial settings and flow rates.
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The electrocardiograph (ECG) was recorded continuously in 20 children undergoing adenoidectomy during halothane anaesthesia. Five surface ECG leads and an oesophageal lead were used. In 11 children, there were QRS complexes which had a shape distinctly different from that of the ordinary sinus-evoked beats. ⋯ Although the anomalous QRS complexes were premature, P waves and P-P intervals were unchanged. In some children, there appeared to be ventricular capture beats and fusion beats. Because of this, and in view of evidence gathered from studies in animals, by other authors, we considered it likely that the anomalous beats were ventricular in origin.