Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparison of the forces exerted during laryngoscopy using disposable and non-disposable laryngoscope blades.
The concern that re-usable equipment may be a source of cross-infection has prompted the increased use of disposable laryngoscope blades. We conducted a study investigating the duration of laryngoscopy and the peak force generated using various laryngoscope blades. Five blades were studied: one reusable Macintosh 3 blade, one disposable metal blade and three plastic disposable blades. ⋯ The mean duration of laryngoscopy with the collar off for the metal blades was 5.6 and 5.4 s, and with the plastic blades 10, 7.2 and 7.5 s (p < 0.0001). The duration of laryngoscopy with the collar applied for the metal blades was 7.1 and 7.5 s, and with the plastic blades 11.8, 9.7 and 9.0 s (p < 0.0001). The use of plastic blades results in both greater peak force and duration of laryngoscopy.
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Randomized Controlled Trial Comparative Study Clinical Trial
Use of the bougie in simulated difficult intubation. 2. Comparison of single-use bougie with multiple-use bougie.
We studied the success rates for tracheal intubation in 32 healthy, anaesthetised patients during simulated grade IIIa laryngoscopy, randomised to either the multiple-use or the single-use bougie. Success rates (primary end-point) and times taken (secondary end-point) to achieve tracheal intubation were recorded. ⋯ With either device, median [range] total tracheal intubation times for successful attempts were < 54 [24-84] s and there were no clinically important differences between these times. We conclude that the multiple-use bougie is a more reliable aid to tracheal intubation than the single-use introducer in grade IIIa laryngoscopy.
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Randomized Controlled Trial Comparative Study Clinical Trial
Use of the bougie in simulated difficult intubation. 1. Comparison of the single-use bougie with the fibrescope.
We studied the success rates for tracheal intubation in 64 healthy patients during simulated grade III laryngoscopy after induction of anaesthesia, using either the single-use bougie or oral flexible intubating fibrescope, both in conjunction with conventional Macintosh laryngoscopy. Patients were randomly allocated to either simulated grade IIIa or grade IIIb laryngoscopy, and also to one of the two study devices. Success rates for tracheal intubation (primary outcome measure) and times taken to achieve intubation (secondary outcome measure) were recorded. ⋯ With either device, median (range) total tracheal intubation times for successful attempts with either grade of laryngoscopy were less than 60 s (19-109) and there were no clinically important differences. We conclude that the fibrescope used in conjunction with Macintosh laryngoscopy is a more reliable method of tracheal intubation than the single-use bougie in both types of grade III laryngoscopy. This finding has implications for the management of patients in whom grade III laryngoscopy is encountered unexpectedly after induction of anaesthesia, and also for the management of patients previously known to have grade III view at laryngoscopy.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparative evaluation of methods for ensuring the correct position of the tracheal tube in children undergoing open heart surgery.
The length of the trachea varies and is relatively short in children, it is therefore difficult to determine the correct depth of tracheal tube placement. In 85 children, the tube was placed using one of the following methods: (i) after deliberate endobronchial intubation, withdrawal to the carina was confirmed by auscultation, and the tube was then withdrawn a further 2 cm (auscultation group); (ii) as above, except that withdrawal to the carina was confirmed by a decrease in peak inspiratory pressure (pressure group); (iii) the tube was placed with a 3.0-cm mark at the vocal cords (mark group). The mean (SD) distance from the tip of the tube to the carina was 1.91 (0.81) cm in the auscultation group, and 1.93 (0.67) cm in the pressure group. ⋯ In the mark group, the tube was located 2.30 (0.98) cm above the carina in children younger than 36 months and was further from the carina [6.16 (1.0) cm] in older children. In 20% of patients initially randomly allocated to the mark group, the mark could not be visualised. In conclusion, the methods described above effectively achieve adequate tracheal tube depth in children.
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Randomized Controlled Trial Clinical Trial
The effect of variable-dose diazepam on dreaming and emergence phenomena in 400 cases of ketamine-fentanyl anaesthesia.
This randomised double-blind field study compared 400 anaesthetics using diazepam (0, 0.025, 0.5, 0.1, 0.175 mg.kg-1) with ketamine (1 mg.kg-1) and fentanyl (1 microg.kg-1) in Melanesian patients. Dreams were very common and generally positive in nature. A minimum of 0.1 mg.kg-1 of diazepam was needed to significantly reduce dreaming when compared with water (67.5% vs. 94.6%; p < 0.0001), and to significantly lower median (95% CI) emergence delirium scores (4 (3-4) vs. 6 (5-7)). ⋯ Higher diazepam doses significantly reduced the increase in blood pressure and heart rate at 3 and 6 min postketamine. When used with ketamine and fentanyl, 0.1 mg.kg-1 of diazepam has favourable psychic and cardiovascular effects. Lower diazepam doses generally had little effect whereas larger doses did not enhance the benefits further.