Do we expect enough?
نویسندگان
چکیده
The use of adrenaline in combination with local anesthetics is a broadly extended practice in surgery for extending the anesthetic effect (up to 200%) and achieve improved hemostasia and therefore enhanced visualization in the surgical field.1 In this practice it is important not only to use adrenaline as a vasoconstrictor but also to observe the prescribed time for the said drug to reach its maximum effect. Classic texts estimate the said waiting time between 7 and 10 min on the basis of the results of a study carried out in 1987 on pigskin with Doppler flowmeter.2 However, more recent studies which applied tissue reflectancy spectroscopy seem to extend the said optimum waiting time up to 25 min.3 These latest studies determined the waiting time after injecting lidocaine with adrenaline to achieve the lowest concentration of hemoglobin at the skin level. Tissue reflectancy spectroscopy provides a more direct estimation of the intra-surgery potential for bleeding in comparison with the isolated arterial blood flow measured with Doppler. The said technique is being applied even for noninvasive monitoring of skin graft perfusion in order to determine feasibility, and one of its most extended applications in daily practice is the omnipresent pulse oximeter. A physiological explanation of this increased optimum waiting time for vasoconstriction is that the vasoconstrictor effect of adrenaline is complex and the vasoconstriction intensity varies with different blood vessel types. Thus, even though the maximum vasoconstriction effect of adrenaline is reached between 7 and 10 min, more time is required to reach a new balance in the local amount of hemoglobin.
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عنوان ژورنال:
- Archivos de la Sociedad Espanola de Oftalmologia
دوره 89 10 شماره
صفحات -
تاریخ انتشار 2014