Epidural and paracervical blockades in obstetrics. Catecholamines, arginine vasopressin and analgesic effect

A comparative study of analgesic and endocrinologic effects of obstetrical epidural anesthesia (EA, n = 23) and paracervical block (PCB, n = 39) was performed. Pain intensity was assessed on a horizontal linear scale. Simultaneously, blood samples for the determination of concentrations of norepinephrine (NE), epinephrine (E) and arginine vasopressin (AVP) were obtained. NE and AVP levels did not bear any relationship to pain scores. Instead, the average plasma E profile during labor was practically identical with the profile of pain scores. Plasma levels of E decreased significantly after EA. A similar but short-lived effect was observed also after PCB. When comparable doses of bupivacaine were used (30 mg in the EA group and 25 mg in the PCB group); initial pain relief after EA and PCB was similar, though after 30 min the pain score increased for patients who received the PCB, while patients who received EA had continued pain relief. Faster absorption of bupivacaine was observed after paracervical than epidural injection. Decreased variability was seen in the fetal cardiograms in 25% after EA and in 33% after PCB. Transient bradycardia was observed in 2 cases after paracervical injection.