Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Changes in intra-ocular pressure during general anaesthesia. A comparison of spontaneous breathing through a laryngeal mask with positive pressure ventilation through a tracheal tube.
Changes in-intra-ocular pressure during spontaneous ventilation with a laryngeal mask were compared with controlled ventilation using a tracheal tube in 40 patients undergoing intra-ocular surgery under general anaesthesia. Intra-ocular pressure was measured before induction, after establishing the airway, at the end of the operation and after removal of the airway device. Anaesthesia was induced with propofol and maintained with enflurane and nitrous oxide in oxygen. ⋯ At the end of surgery, intra-ocular pressure (mmHg) was 11.2 and 8.6 during spontaneous or controlled ventilation respectively. One min after removal of the device, mean intra-ocular pressure (mmHg) in the tracheal tube group (16.0) was slightly higher than baseline (15.3) and was significantly higher than the laryngeal mask group (10.9) (p < 0.01). Spontaneous ventilation with a laryngeal mask is an acceptable alternative to controlled ventilation with tracheal intubation in elective intra-ocular surgery.
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparison of three variable performance devices for postoperative oxygen therapy.
Eleven patients in the intensive care unit following major abdominal surgery with a nasogastric tube in situ and receiving oxygen via facemask were allocated to receive in a random sequence oxygen at 4 l.min-1 via a Hudson mask, nasal cannulae or a nasal catheter with foam collar at the distal end. A significantly greater PaO2 was achieved using both the nasal catheter with foam collar (p < 0.01) and Hudson mask (p < 0.05) compared to the nasal cannulae. ⋯ In the majority of postoperative patients in whom a variable performance device is indicated, nasal devices appear preferable in terms of patient comfort and compliance. The nasal catheter with foam collar produced a significantly greater PaO2 than nasal cannulae in patients with a nasogastric tube in situ.
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In characterising the forces exerted during laryngoscopy it is accepted that the significant force component is that which is parallel to the axis of the laryngoscope handle. This paper describes a new method of evaluating the forces exerted at laryngoscopy. A laryngoscope handle has been redesigned, incorporating a force-displacement transducer on the handle at the end opposite to where the blade is attached. ⋯ Thus, the force transmitted to the transducer is essentially constant regardless of where the load is applied along the blade. The output from the system is directly downloaded to a laptop computer and the data analysed almost instantaneously to determine the duration of laryngoscopy, the peak forces applied, the mean force with its standard deviation and graphic display of the data. Provision has been made for data entry checks, recording patient details and study data, and creating a data base for the storage and retrieval of the study details.
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A postal survey of all maternity units in the UK was conducted to gain information regarding the management of inadvertent dural taps occurring during the sitting of epidurals for pain relief in labour. Of the units surveyed only 58.5% had a written protocol for the management of dural taps. ⋯ In 46% of the units, patients who had a dural tap were allowed to push in the second stage of labour. As prophylaxis against the development of headache, 70% of the units infused crystalloids into the epidural space, whereas only 8.6% were in favour of an early prophylactic blood patch.