Die sympathoadrenerge Streßreaktion bei Ohroperationen unter verschiedenen Anästhesietechniken*

Zusammenfassung

Sympathoadrenerge Streßreaktionen während mehrstündiger Ohroperationen wurden bei insgesamt 49 Patienten untersucht, die randomisiert vier Gruppen mit kombinierter Allgemein- und Lokalanästhesie bzw. alleiniger Lokalanästhesie zugeordnet wurden. Die Katecholaminkonzentrationen im Plasma verließen bei den Patientengruppen mit Allgemeinanästhesie durchgehend nicht den Normbereich, im Kollektiv mit alleiniger Lokalanästhesie lagen sie dagegen deutlich darüber. Auswirkungen auf das Kreislaufverhalten sowie die „Streß-Metabolite” Glukose, Laktat und Freies Glyzerin blieben dagegen gering. Die ausgeprägtere Streßreduktion bei der Kombination von Allgemeinund Lokalanästhesie läßt diese Verfahren als besonders geeignet zur Betreuung von Risikopatienten erscheinen.

Summary

The aim of the present study was to investigate the effects of various anaesthetic procedures on the endocrine stress responses during ear microsurgical operations. Simple mastoidectomies, radical mastoidectomies and tympano plastics were carried out in 49 patients under the following randomised anaesthetic procedures: Group 1 halothane anaesthesia and retroauricular infiltration anaesthesia with lidocaine and ornipressin (n = 14), Group 2 fentanyl anaesthesia and retroauricular anaesthesia with lidocaine and ornipressin (n = 10), Group 3 fentanyl anaesthesia and retroauricular infiltration anaesthesia with lidocaine and epinephrine (n = 14), and Group 4 retroauricular infiltration anaesthesia with prilocaine and epinephrine (n = 14). The plasma levels of epinephrine, norepinephrine, glucose, lactate and free glycerol were measured in addition to mean arterial pressure (MAP) and heart rate (HR) immediately before anaesthesia, 10 minutes after skin incision, 10 minutes after having started bone drilling, at the end of the operation and 3 hours after operation. All data were subjected to covariance analysis including the age factor. Plasma catecholamine concentrations remained within the normal range during the investigation in patients subjected to general anaesthesia (Groups 1-3). Plasma catecholamines (epinephrine and norepinephrine) increased significantly in Group 4 (retroauricular infiltration anaesthesia). There were no group variabilities with regard to MAP and HR. The plasma levels of epinephrine and norepinephrine demonstrate a direct response to stress followed by a secondary change in glucose, lactate and free glycerol. The beneficial effect of general anaesthesia is documented by normal plasma levels of epinephrine and norepinephrine throughout the operation. Although all patients received the same premedication, there was an increase in plasma catecholamines in group 4 only; this might be due to special anticipatory anxiety. In addition there was a further increase in catecholamine levels in these patients immediately after the beginning of the operation - probably due to the surgical stimulus. Our results indicate that retroauricular infiltration anaesthesia might not be the method of choice, especially in high-risk patients.