Intrathecal ropivacaine in cesarean delivery.

OBJECTIVE: The aim of the present study was to evaluate the optimum dose of ropivacaine by comparing three different dosing regimens of isobaric ropivacaine 1% (naropin 10 mg/ml, Astra Zeneca) administered intrathecally and to demonstrate the effects of anesthesia in pregnant women scheduled for cesarean section. PATIENTS AND METHODS: Sixty ASA grade I-II patients were scheduled to undergo elective cesarean sections under spinal anesthesia. The patients were randomly assigned into three groups. Group 1 received 15 mg ropivacaine 1%, Group 2 received 20 mg ropivacaine 1%, and Group 3 received 25 mg ropivacaine 1%. RESULTS: Intraoperative hemodynamic variables were not significantly different between the three groups, and sensory block time, motor block time and time to reach maximal sensory block time, and motor block time were similar between the three groups. The time to two-segment regression of sensory block was longer in Group 3 compared to other groups, and the difference was statistically significant (p < 0.05). The motor block time was longer with higher doses of ropivacaine; however, the difference was not statistically significant. CONCLUSION: Ropivacaine administration produced rapid induction of anesthesia and satisfactory anesthesia level, ropivacaine 15 mg and 20 mg dosing regimens are satisfactory for spinal anesthesia.

The effects of opioids, local anesthetics and adjuvants on isolated pregnant rat uterine muscles.

Local anaesthetics, opioids and adjuvants are often used for managing labor pain. Some others of these agents are reported to cause alterations on uterine contractility during labor. However, there are controversies and the effects of some others are unknown. In the present study, we aimed to elucidate the effects of opioids such as alfentanyl, meperidine, remifentanyl; local anesthetics such as mepivacaine, ropivacaine, bupivacaine; and adjuvants such as clonidine and midazolam on isolated pregnant rat uterine muscle. Strips of longitudinal uterine smooth muscle obtained from rats pregnant for 18-21 days were suspended in 20 ml organ baths. Isometric tension was continuously measured with an isometric force transducer connected to a computer-based data acquisition system. The effects of cumulative concentrations of alfentanyl, meperidine, remifentanyl, mepivacaine, ropivacaine, bupivacaine, clonidine and midazolam (10(-8) - 10(-4) M, for all) on contractions induced by oxytocin (1 mU/ml) were studied. Alfentanyl (10(-5) M), meperidine (10(-5) M), remifentanyl (10(-4) M), bupivacaine (10(-4) M), ropivacaine (10(-4) M) and midazolam (3 x 10(-5) M) caused significant decreases in contractile responses of uterine strips to oxytocin. Contrastingly, mepivacaine increased (33.1% +/- 7.2%) oxytocin-induced contractions of uterine strips while clonidine exerted no significant effect. The sensitivity of myometrial preparations to tested local anesthetics or opioids did not differ significantly. The findings of the present study demonstrated that some local anesthetics, opioids and adjuvants caused significant and agent-specific alterations on contractility of the pregnant rat myometrium. Therefore, they seemed to have a potential to influence uterine contractility during clinical management of pain during labor. However, further research is needed to extrapolate these finding to clinical practice.

Comparison of epidural and combined spinal-epidural analgesia in the management of labour without pain.

The effects of combined spinal-epidural analgesia (CSEA) and epidural analgesia (EA) were studied in 50 healthy parturients randomly allocated to receive bupivacaine plus fentanyl either epidurally, or intrathecally and epidurally. Significant differences from baseline values were seen in systolic blood pressure at all time-points except for 4 h in the EA group and at 3 and 4 h in the CSEA group. Significant differences from baseline values were seen in diastolic blood pressure at 1, 2, 3 and 4 h in the EA group, whereas no significant differences from baseline were seen in the CSEA group. Pain scores in both groups were significantly decreased compared with baseline and all scores, except at 2h, were significantly lower in the CSEA group compared with the EA group. The duration of labour and total amount of drugs used were significantly decreased and cervical dilatation was faster with CSEA compared with EA. In conclusion, CSEA was associated with more rapid onset of analgesia and faster progress in cervical dilatation compared with EA, and can be used safely for labour analgesia.

Pain relief for children after adenotonsillectomy.

Effective pain relief following adenotonsillectomy in children remains a challenge. This study evaluated the effects of intramuscular 0.5 mg/kg ketamine, 1 mg/kg tramadol or 1 mg/kg meperidine on post-operative pain and recovery in 45 children aged 1-7 years undergoing adenotonsillectomy. Anaesthesia was induced with thiopental or sevoflurane (with succinylcholine for intubation) and was maintained with sevoflurane in oxygen and nitrous oxide. Post-operative pain was scored blind using a modified Toddler-Preschooler Post-Operative Pain Scale 30, 60, 120 and 240 min after tracheal extubation. Post-operative agitation scores were also recorded. Mean post-operative pain score was significantly higher in the tramadol-treated group compared with the meperidine-treated group 120 min after extubation. At all other time-points after extubation, mean post-operative pain scores were similar for the three treatment groups. Ketamine was associated with a significantly higher mean agitation score compared with tramadol and meperidine. We conclude that the effects of ketamine, meperidine and tramadol on post-operative pain following adenotonsillectomy in children were similar.

Effects of hyperbaric spinal ropivacaine for caesarean section: with or without fentanyl.

BACKGROUND AND OBJECTIVE: Adding various opioids to the local anaesthetic solution administrated intrathecally improves the analgesic potency of spinal analgesia. The purpose of this study was to evaluate the efficacy and safety of intrathecal fentanyl 10 microg added to 15 mg hyperbaric ropivacaine in patients undergoing caesarean section under spinal anaesthesia. METHODS: Thirty-seven healthy, full-term parturients were randomly assigned into two groups: Group S (saline group, n=17) received 15 mg hyperbaric ropivacaine in 2.5 mL + 0.5 mL saline; Group F (fentanyl group, n=20) received 15 mg hyperbaric ropivacaine in 2.5 mL + 10 microg fentanyl in 0.5 mL, intrathecally. Characteristics of spinal block, intraoperative quality of spinal anaesthesia, time to first feeling of pain (complete analgesia), time to first request of analgesics postoperatively (effective analgesia), side-effects and fetal outcomes were evaluated. RESULTS: Regression of sensory block to L5 was significantly prolonged in the fentanyl group compared with the saline group (P = 0.001). Time to the first feeling of pain (130.6 +/- 15.8 min vs. 154.3 +/- 31.1 min; P = 0.008) and the first analgesic requirement (161.2 +/- 32.6 min vs. 213.0 +/- 29.3 min; P < 0.001) were significantly shorter in the saline group compared with the fentanyl group. Side-effects, umbilical arterial and venous blood gases did not differ between the groups. Apgar scores were similar in both groups and no infants had an Apgar score < or =7 at 5 min. CONCLUSIONS: The addition of fentanyl 10 microg, to hyperbaric ropivacaine 15 mg, for spinal anaesthesia increased the duration of analgesia in the early postoperative period in patients undergoing caesarean delivery.

The analgesic and sedative effects of intrathecal midazolam in perianal surgery.

BACKGROUND AND OBJECTIVE: Our purpose was to evaluate the analgesic and sedative effects of intrathecal midazolam when added to spinal bupivacaine in patients undergoing perianal surgery under spinal anaesthesia. METHODS: Forty-four patients were randomly allocated into two equal groups: Group I (B) received hyperbaric bupivacaine 0.5% 2 mL + saline 0.9% 1 mL in a total volume of 3 mL intrathecally; Group II (BM) received hyperbaric bupivacaine 0.5% 2 mL + 1 mL of 2mg preservative-free midazolam in a total volume of 3 mL intrathecally. In both groups, the onset and recovery times of sensory block, the degree and recovery times of motor block as well as the sedation and visual analogue pain scores were recorded, and statistically compared. RESULTS: In Group BM, the postoperative visual analogue pain scores were significantly lower at the first 4 h (P < 0.05), the average time until the first dose of additional analgesic requirement was significantly longer (P < 0.05), and sedation scales were significantly higher (P < 0.05), compared to Group B. There were no statistically significant differences in the onset and the full recovery times of sensory and motor blocks in the two groups. CONCLUSION: The use of intrathecal midazolam combined with intrathecal bupivacaine produces a more effective and longer analgesia with a mild sedative effect in perianal surgery.

The effects of bupivacaine, ropivacaine and mepivacaine on the contractility of rat myometrium.

Local anesthetic agents are commonly used for obstetric anesthesia and analgesia. We determined the effects of bupivacaine, ropivacaine and mepivacaine on the contractility of isolated pregnant rat uterine muscle strips. Uterine specimens were obtained from 18- to 21-day pregnant Wistar rats (n = 28). Myometrial strips were obtained from the uterine horns after removing the fetuses and non-uterine tissue, incubated in organ baths and contractions stimulated with oxytocin. When contractions became regular, strips were exposed to increasing concentrations of the study drugs. Mepivacaine (n = 8), ropivacaine (n = 10) and bupivacaine (n = 10) were used at cumulative doses from 10(-8) to 10(-4) mol/L. Two of the local anesthetics, bupivacaine most, ropivacaine least, caused a dose-dependent inhibition of uterine contractility. In contrast, mepivacaine significantly increased uterine contractility. Bupivacaine, ropivacaine and mepivacaine were found to have no effect on frequency of uterine contractions. These results demonstrate that bupivacaine and ropivacaine may inhibit myometrium contractility.

Acute subdural haematoma after accidental dural puncture during epidural anaesthesia.

A case is reported of acute intracranial subdural haematoma following accidental dural puncture during epidural anaesthesia. A 36-year-old primigravida with a gestation of 37 weeks and 3 days underwent caesarean section for which epidural anaesthesia was initially planned. An 18-gauge Tuohy needle was inserted into the L3-4 interspace but accidental dural puncture occurred. The needle was removed and general anaesthesia was initiated for surgery. On the second day post partum, the patient described a headache in both occipital area and neck that was relieved by lying down. On the seventh post-partum day she suffered tonic-clonic convulsions and underwent computerised tomography (CT). Despite different analgesic treatments and a normal CT, the patient suffered severe headaches in the following days. Magnetic resonance imaging revealed a 4-mm subdural hematoma in the right frontal area. The persisting headache decreased on day 12 and disappeared on day 14. The patient was discharged from hospital on day 15. The presence of post dural puncture headache complicated by atypical neurological deterioration following epidural anaesthesia should prompt the anaesthetist to consider the existence of intracranial complications and to seek immediate clinical and radiological diagnosis.