British journal of anaesthesia
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Comparative Study
Tracheal intubation in a manikin: comparison of supine and left lateral positions.
Tracheal intubation in the left lateral position may be necessary in some circumstances. Using a manikin we demonstrated that anaesthetic trainees found tracheal intubation in the left lateral position was more difficult and took longer than in the supine position. However, the time to successful tracheal intubation decreased with practice, indicating the presence of a learning curve. We suggest that tracheal intubation in the left lateral position should become part of training in the management of the difficult airway.
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Comparative Study
Use of the laryngeal mask airway after oesophageal intubation.
We have compared insertion of a tracheal tube and laryngeal mask airway (LMA) both with and without the presence of a tube in the oesophagus in 20 ASA I and II patients undergoing elective laparoscopy. After induction of anaesthesia and neuromuscular block, we measured the times for an experienced anaesthetist to correctly position both an LMA and a tracheal tube with and without a tube in the oesophagus. The time to intubation was significantly less with the LMA than with the tracheal tube, both with and without an oesophageal tube in place (P < 0.05). We conclude that if a tracheal tube is placed unintentionally in the oesophagus, an LMA may be used subsequently to provide rapid and effective oxygenation of the patient.
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Mechanical hyperventilation may produce hypocapnic apnoea below the carbon dioxide off-switch threshold whereas an increase in arterial PCO2 after post-hyperventilation apnoea causes reappearance of respiratory effort above the carbon dioxide on-switch threshold. To study the effects of surgical stimulation on these two thresholds, we have measured end-tidal PCO2 (PE'CO2) at the two thresholds, before and during surgical stimulation, in 14 patients undergoing mastectomy, anaesthetized with sevoflurane (1.2 MAC). Based on the reproducibility of the results, data from 11 patients were analysed and data from the three other patients were discarded. ⋯ During surgical stimulation, resting PE'CO2' off-switch threshold and on-switch threshold were 4.8 (0.2), 4.1 (0.2) and 4.7 (0.2) kPa, respectively. Although the off-switch threshold was significantly less than resting PE'CO2 (P < 0.01), there were no significant differences between resting PE'CO2 and on-switch threshold. These results indicate that surgical stimulation does not affect equally the carbon dioxide on- and off-switch thresholds.
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A 22-yr-old male had a head injury after a road traffic accident. His trachea was intubated for 5 days with a high-volume, low-pressure cuffed tracheal tube. ⋯ The patient underwent resection anastomosis of the destroyed tracheal segment which, on histological examination, showed fibrous tissue and bone formation. It is believed that excessive cuff pressure was the cause of the damage, as monitoring cuff pressure has not yet become a routine practice in anaesthesia and intensive care.