European journal of anaesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects on vocal function and incidence of laryngeal disorder when using a laryngeal mask airway in comparison with an endotracheal tube.
A study of 56 patients was undertaken to determine whether there is a difference in the effect of the laryngeal mask airway and the endotracheal tube on the vocal tract after short-duration anaesthesia. All the patients were interviewed pre- and post-operatively. In 43 patients, it was possible to assess the larynx using videoendoscopy and videostrobolaryngoscopy both pre- and post-operatively. ⋯ The videostrobolaryngoscopy demonstrated minor lesions of the vocal tract in six patients in the ETT group and in one patient in the LMA group. Of the 12 voice variables evaluated, there was no significant difference in any parameter between the two groups. Both groups had a higher fundamental frequency post-operatively.
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Randomized Controlled Trial Comparative Study Clinical Trial
Laryngeal mask airway insertion using propofol without muscle relaxants: a comparative study of pretreatment with midazolam or fentanyl.
We determined the effects of pretreatment with midazolam or fentanyl on the ease of laryngeal mask airway insertion using propofol without a muscle relaxant. One hundred and eighty ASA class I or II patients were randomly allocated to one of three groups, 60 patients per group, to receive either placebo (Group C), midazolam 0.05 mg kg-1 (Group M) or fentanyl 2 micrograms kg-1 (Group F), respectively. Following intravenous administration of these drugs, Group C received propofol 2.5 (Group C-2.5) or 3.0 mg kg-1 (Group C-3.0). ⋯ Airway obstruction and inadequate jaw relaxation, which were occasionally recognized in Group C and Group F patients, were not observed in Group M-2.5. Overall the ease of LMA insertion was significantly better in Group M-2.0, Group M-2.5 and Group F-2.5 than in Group C-2.5, however, the blood pressure in Group F after LMA insertion was significantly lower than in Group M. We conclude that pretreatment with midazolam 0.05 mg combined with propofol 2.5 mg kg-1 provides safe and satisfactory conditions for LMA insertion.
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Randomized Controlled Trial Comparative Study Clinical Trial
Arterial to end-tidal carbon dioxide tension difference in anaesthetized adults mechanically ventilated via a laryngeal mask or a cuffed oropharyngeal airway.
To evaluate arterial (PaCO2), end-tidal (PETCO2) and carbon dioxide tension difference during mechanical ventilation with extratracheal airways, 60 patients ASA physical status I-II, receiving general anaesthesia for minor extra-abdominal procedures were randomly allocated to receive either a cuffed oropharyngeal airway (group COPA, n = 30) or a laryngeal mask (group LMA, n = 30). The lungs were mechanically ventilated by IPPV using a 60% nitrous oxide and 1-1.5% isoflurane in oxygen mixture (VT = 8 mL kg-1; RR = 12 b min-1; l/E = 1/2). After PETCO2 had been stable for at least 10 min after airway placement, haemodynamic variables and PETCO2 were recorded and an arterial blood sample was obtained for measurement of PaCO2. ⋯ Airway manipulation, to maintain adequate ventilation, was required in only nine patients in the cuffed oropharyngeal airway group (30%) (P < 0.0005); however, in no case was it necessary to remove the designated extratracheal airway due to unsuccessful mechanical ventilation. The mean difference between arterial and end-tidal carbon dioxide partial pressure was 0.4 +/- 0.3 KPa in the laryngeal mask group (95% confidence intervals: 0.3-0.5 KPa) and 0.3 +/- 0.26 KPa in the cuffed oropharyngeal airway group (95% confidence intervals: 0.24-0.4 KPa) (P = NS). We conclude that in healthy adults who are mechanically ventilated via the cuffed oropharyngeal airway, the end-tidal carbon dioxide determination is as accurate an indicator of PaCO2 as that measured via the laryngeal mask, allowing capnometry to be reliably used to evaluate the adequacy of ventilation.