Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison between two fibrescopes with different diameter insertion cords for fibreoptic intubation.
Two fibreoptic bronchoscopes with insertion cords of different diameters (3.7 and 5.0 mm) were compared during fibreoptic intubation in 84 adult patients (ASA 1-2) undergoing orotracheal intubation under general anaesthesia. The fibrescope used was randomly selected. The incidence of resistance to passage of the tracheal tube through the vocal cords was higher using the thinner fibrescope, 14/40 (35%) as compared with the thicker fibrescope, 5/44 (11%) (p < 0.05). ⋯ The duration of intubation was significantly shorter with the thicker fibrescope (p < 0.05). There were two instances of oesophageal intubation with the thinner fibrescope. A fibrescope with a thicker insertion cord is more suitable for orotracheal fibreoptic intubation in adult patients.
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The tracheas of 20 ASA grade 1 and 2 patients were each consecutively intubated with an oral and nasal cuffed tracheal tube. Measurements of tube movement, as the position of the head and neck altered, were made with a fibreoptic bronchoscope. Both oral and nasal tubes moved an average distance of 15 mm towards the carina with head and neck flexion and 8.5 mm away with head and neck extension. ⋯ Optimal placement of tracheal tubes can be aided with a single guide mark placed 3 cm proximal to the cuff and 8 cm proximal to the distal end, which may reduce complications arising from this movement. This is a better method in women than inserting a pre-determined length of tracheal tube measured from the lips or nares. However, current guide marks vary in their position relative to the cuff and tip of the tube.
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Randomized Controlled Trial Comparative Study Clinical Trial
The role of continuous positive airway pressure during weaning from mechanical ventilation in cardiac surgical patients.
We investigated the effects of providing patients with continuous positive airway pressure during a short weaning period from mechanical ventilation to extubation. Following elective primary aortocoronary bypass surgery employing cardiopulmonary bypass, 80 patients received intermittent positive pressure ventilation for 5 h. At the end of this time patients were randomly allocated to one of the following three groups for a 2 h period of spontaneous respiration prior to extubation: group CPAP0 = T-piece circuit (n = 27); group CPAP5 = 5 cmH2O of continuous positive airway pressure (n = 27); group CPAP10 = 10 cmH2O of continuous positive airway pressure (n = 26). ⋯ All patients had good pre-operative lung function. There was a significant increase in the median alveolar-arterial oxygen partial pressure difference and a decrease in the oxygenation index in all three groups during the period of added inspired oxygen which persisted until 24 h post-extubation, but there were no differences between the groups. In patients with good pre-operative lung function requiring primary aortocoronary bypass surgery, the use of continuous positive airway pressure confers no advantage over a simple T-piece attachment during the short period of weaning from mechanical ventilation to extubation.
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Comparative Study
The TOF-Guard neuromuscular transmission monitor. A comparison with the Myograph 2000.
The TOF-Guard neuromuscular monitor uses an accelerometer to measure the response to nerve stimulation. In this study, we have compared it to a standard mechanomyographic monitor, the Myograph 2000, for neuromuscular monitoring in 28 subjects. A train-of-four mode of stimulation was used in both cases. ⋯ The 95% limits for the TOF-Guard measured train of four ratio were from 0.47 to 0.99, at the Myograph reading of 0.7. We recommend that information from the TOF-Guard and the Myograph 2000 should not be used interchangeably. However, the TOF-Guard is likely to improve considerably on tactile evaluation of the responses to stimulation.