A comparison of the Pentax Airway Scope™ with the Airtraq™ in an infant manikin.

We compared the Pentax Airway Scope(TM) with the Airtraq(TM) optical laryngoscope in an infant manikin. Twenty-three anaesthetists randomly performed tracheal intubation: at rest, (a) with the Airway Scope and (b) with the Airtraq; and during chest compressions, (c) with the Airway Scope and (d) with the Airtraq. The success rate, modified Cormack and Lehane classification for glottic view, time taken to view the glottis, and time to place the tracheal tube were recorded. There was no difference in intubation success rate or quality of glottic view between the two devices. The median (IQR [range]) time taken to obtain a view of the glottis was 4.5 (3.7-6.4 [1.8-14.0]) s using the Airway Scope compared with 7.1 (5.5-9.6 [3.3-12.0]) s using the Airtraq (p = 0.001), and to successful placement of the tracheal tube was 8.3 (6.8-9.4 [3.7-20.7]) s using the Airway Scope compared with 11.2 (10.4-13.8 [4.9-23.7]) s using the Airtraq (p = 0.001). During chest compressions, the median (IQR [range]) time taken to view the glottis was 5.1 (4.0-7.2 [2.0-12.4]) s using the Airway Scope compared with 7.5 (5.0-13.2 [4.2-26.4]) s using the Airtraq (p = 0.006), and to successful placement of the tracheal tube was 9.5 (6.6-13.7 [4.5-16.2]) s using the Airway Scope compared with 11.7 (9.1-18.1 [6.2-37.4]) s using the Airtraq (p = 0.022). We conclude that both devices provided good quality views of the glottis and successful tracheal intubation in an infant manikin both at rest and during external chest compressions. Use of the Airway Scope resulted in a shorter time to view the glottis and perform successful tracheal intubation compared with the Airtraq.

The Parker Flex-Tip tracheal tube makes endotracheal intubation with the Bullard laryngoscope easier and faster.

BACKGROUND: The Bullard laryngoscope can be useful in management of difficult airway. When the endotracheal tube is advanced over the original Bullard laryngoscope stylet, the endotracheal tube sometimes makes contact with structures around the vocal cords, especially the right arytenoids. A similar problem also occurs with flexible fibreoptic intubation and it has been shown that use of the Parker Flex-Tip tube usually resolves the problem. In this study we tested our hypothesis that use of the Parker Flex-Tip tube might improve endotracheal tube passage with the Bullard laryngoscope. METHODS: Forty patients scheduled for elective anaesthesia were randomly assigned into group ST (standard tube) or Group PT (Parker Flex-Tip tube). The time taken to achieve successful endotracheal tube placement after obtaining the best laryngeal view, the number of attempts at intubation and the incidences of successful intubation at first attempt and of re-direction of the Bullard laryngoscope during intubation were recorded. Unpaired t-test and chi2-test were employed and P < 0.05 was considered significant. RESULTS: Use of the Parker Flex-Tip tube reduced the time required for successful endotracheal tube placement after the best laryngeal view was obtained from 14 +/- 6 to 6 +/- 2 s (P < 0.01). It also reduced the incidence of requirement for re-direction of the Bullard laryngoscope during intubation from 10/19 to 1/19 (P < 0.01). The incidence of successful intubation at the first attempt (18/19 vs. 15/19) was higher in the PT group but the difference was not statistically significant. CONCLUSIONS: During intubation with the Bullard laryngoscope, use of the Parker Flex-Tip tube is associated with more rapid success and a lower incidence of re-direction of the Bullard laryngoscope during endotracheal intubation when compared to a standard endotracheal tube.

Accelerated inactivation of cardiac L-type calcium channels triggered by anaesthetic-induced preconditioning.

BACKGROUND AND PURPOSE: Cardioprotection against ischaemia by anaesthetic-induced preconditioning (APC) is well established. However, the mechanism underlying Ca(2+) overload attenuation by APC is unknown. The effects of APC by isoflurane on the cardiac L-type Ca channel were investigated. EXPERIMENTAL APPROACH: In a model of in vivo APC, Wistar rats were exposed to isoflurane (1.4%), delivered via a vaporizer in an enclosure, prior to thoracotomy. The Dahl S rats were similarly preconditioned to determine strain-dependent effects. Whole-cell patch clamp using cardiac ventricular myocytes was used to determine the L-type Ca(2+) current (I(Ca,L)) characteristics and calmodulin (CaM) levels were determined by Western blot analysis. Cytosolic Ca(2+) levels were monitored using fluo-4-AM. Action potential (AP) simulations examined the effects of APC. KEY RESULTS: In Wistar rats, APC significantly accelerated I(Ca,L) inactivation kinetics. This was abolished when external Ca(2+) was replaced with Ba(2+), suggesting that Ca(2+)-dependent inactivation of I(Ca,L) was modulated by APC. Expression levels of CaM, a determinant of I(Ca,L) inactivation, were not affected. Attenuation of cytosolic Ca(2+) accumulation following oxidative stress was observed in the APC group. Simulations showed that the accelerated inactivation of I(Ca,L) resulted in a shortening of the AP duration. The Dahl S rat strain was resistant to APC and changes in I(Ca,L) inactivation were not observed in cardiomyocytes prepared from these rats. CONCLUSIONS AND IMPLICATIONS: APC triggered persistent changes in the inactivation of cardiac L-type Ca channels. This can potentially lead to a reduction in Ca(2+) influx and attenuation of Ca(2+) overload during ischaemia/reperfusion.