[Anaesthesia for caesarean section. Comparison of two general anaesthetic regimens and spinal anaesthesia]

Abstract

Objectives: The study was undertaken to compare different anaesthetic techniques for scheduled or urgent caesarean section with respect to maternal circulatory parameters, maternal and fetal endocrine stress response, fetal vitality parameters and further clinical parameters such as recovery and analgesic demand.

Methods: After ethical approval,patients scheduled for general anaesthesia were randomly allocated to the esketamine group ( n=21; induction with 0.5 mg/kg BW esketamine and 1.5 mg/kg BW methohexitone, ventilation until cord cutting with FiO(2) 1.0) and the sevoflurane-group ( n=21; induction with 1.5-2.0 mg/kg BW methohexitone, ventilation until uterotomia with N(2)O/O(2) [FiO(2) 0,5] and endtidal sevoflurane concentrations about 1.0 vol%). After fetal development, all patients received 2.5 microg/kg BW fentanyl and sevoflurane (about 1.0 vol% endtidal) during ventilation with N(2)O/O(2) (FiO(2) 0.33). As a further control, a group with spinal anaesthesia ( n=22; 2.6-3.0 ml isobaric bupivacaine 0.5 %) was investigated. Maternal circulatory and endocrine plasmatic stress parameters were investigated at five time points and fetal parameters once after development.alpha< or =0.05 was considered significant.

Results: Biometric data were comparable in all groups. Systolic arterial pressure was higher in the esketamine group ( p=0.008), whereas the heart rate was lower during spinal anaesthesia ( p<0.001). Plasma noradrenaline decreased in all collectives ( p<0.001) and mean group levels of noradrenaline ( p=0.04) and adrenaline ( p<0.001) were lower during spinal anaesthesia. In all groups, antidiuretic hormone (ADH) remained within the normal range or was slightly increased. Adrenocorticotropic hormone (ACTH) initially increased in all groups and decreased in later time course ( p<0.001). Cortisol increased in all groups ( p<0.001) but group levels were lower during spinal anaesthesia ( p<0.001). In the groups with general anaesthesia, no significant differences in recovery times were obvious, and neither recall nor dream reactions were observed. Postoperative hypoxic incidents (psaO(2) <90%) were comparable between the groups. After spinal anaesthesia, first analgesic demand was later than in the controls ( p=0.001), and the total amount of piritramide was lower ( p=0.02). Nausea and vomiting were more frequent during spinal anaesthesia ( p=0.03). All patients were content with their regimen. Apgar scores, pH-values and adrenaline, noradrenaline and cortisol in plasma were comparable in all groups of children (69 children, 5 gemini). The fetal concentration of esketamine (251 ng/ml) was lower than the corresponding maternal values (493 ng/ml).

Conclusions: When compared with methohexitone, sevoflurane and N(2)O for caesarean section, initial total intravenous anaesthesia with esketamine and methohexitone mediated specific antinociception without negative maternal or fetal effects and not taking invasion kinetics or elimination between uterotomia and cord cutting into consideration. Avoidance of N(2)O allows optimal oxygenation of the fetomaternal unit. Stress protection and hemodynamic responses were well balanced, and intraoperative recall or negative dream reactions were lacking. Superior postoperative pain protection was advantageous after spinal anaesthesia, but in contrast, nausea and vomiting were more frequent in this group.