Ropivacaine cardiac toxicity--not as troublesome as bupivacaine

Continuous Analgesia with Intercostal Catheterization after Thoracoscopy

BACKGROUND

 There are few studies on continuous intercostal nerve block after single operation hole thoracoscopic surgery, that is, two-port thoracoscopic surgery.

OBJECTIVE

 To evaluate the analgesic effect of continuous intercostal nerve block after thoracoscopic surgery.

METHODS

 A total of 80 patients who underwent single operation hole thoracoscopic surgery in our hospital between September 2020 and June 2021 were enrolled and divided into two groups. Based on basic analgesia, an intercostal catheter was placed during the operation for continuous intercostal block analgesia after the operation in the experimental group (group A, n = 40). The control group (group B, n = 40) was treated with sufentanil intravenous analgesia after surgery, which is namely "basic analgesia." The postoperative pain scores, restlessness during the recovery period, effect on reducing opioid use, postoperative chest complications, patient satisfaction, etc., were compared between the two groups.

RESULTS

 The pain scores of patients in group A were significantly lower compared with those in group B at 12, 24, 36, and 48 hours after surgery (3.325 ± 1.163 vs. 4.550 ± 1.176, 2.650 ± 1.001 vs. 4.000 ± 1.038, 2.325 ± 0.917 vs. 3.700 ± 0.966, and 1.775 ± 1.050 vs. 3.150 ± 1.075, p < 0.001, respectively). Sufentanil consumption in group A was significantly lower than in group B at 48 hours after surgery (98.625 ± 4.158 vs. 106.000 ± 7.228, p < 0.001).

CONCLUSION

 Multimodal analgesia is ideal for early pain control after thoracotomy. A continuous intercostal nerve block can effectively reduce postoperative pain in patients.

TASK Channel Deletion Reduces Sensitivity to Local Anesthetic-induced Seizures

BACKGROUND

Local anesthetics (LAs) are typically used for regional anesthesia but can be given systemically to mitigate postoperative pain, supplement general anesthesia, or prevent cardiac arrhythmias. However, systemic application or inadvertent intravenous injection can be associated with substantial toxicity, including seizure induction. The molecular basis for this toxic action remains unclear.

METHODS

We characterized inhibition by different LAs of homomeric and heteromeric K channels containing TASK-1 (K2P3.1, KCNK3) and TASK-3 (K2P9.1, KCNK9) subunits in a mammalian expression system. In addition, we used TASK-1/TASK-3 knockout mice to test the possibility that TASK channels contribute to LA-evoked seizures.

RESULTS

LAs inhibited homomeric and heteromeric TASK channels in a range relevant for seizure induction; channels containing TASK-1 subunits were most sensitive and IC₅₀ values indicated a rank order potency of bupivacaine > ropivacaine >> lidocaine. LAs induced tonic-clonic seizures in mice with the same rank order potency, but higher LA doses were required to evoke seizures in TASK knockout mice. For bupivacaine, which produced the longest seizure times, seizure duration was significantly shorter in TASK knockout mice; bupivacaine-induced seizures were associated with an increase in electroencephalogram power at frequencies less than 5 Hz in both wild-type and TASK knockout mice.

CONCLUSIONS

These data suggest that increased neuronal excitability associated with TASK channel inhibition by LAs contributes to seizure induction. Because all LAs were capable of evoking seizures in TASK channel deleted mice, albeit at higher doses, the results imply that other molecular targets must also be involved in this toxic action.

Epidural ropivacaine -- where are the benefits? A prospective, randomized, double-blind trial in patients with retropubic prostatectomy

BACKGROUND

In comparison with bupivacaine, ropivacaine exhibits comparable anaesthetic effects but with less motor impairment and systemic toxicity. However, the analgesic potency may differ. For example, ropivacaine during obstetric epidural analgesia provides an approximately 40% lower analgesic potency than bupivacaine. Equal visual analogue pain scores require significantly higher dosages of ropivacaine, and general statements about a favourable benefit-risk profile relative to that of bupivacaine may therefore have limited clinical impact. We addressed this topic in a male pain model by evaluating the analgesic efficacy of epidural ropivacaine 0.2% vs. bupivacaine 0.125% after retropubic prostatectomy.

METHODS

Forty patients scheduled for retropubic prostatectomy were randomly assigned to two groups (20 patients per group). In a double-blind prospective design, patient-controlled lumbar epidural analgesia was provided by ropivacaine 0.2% in the ropivacaine group and by bupivacaine 0.125% in the bupivacaine group. The primary endpoint was the total amount of local anaesthetic consumption. The secondary endpoints were the numeric rating scale scores for rest and dynamic pain and the degree of motor impairment.

RESULTS

Ropivacaine consumption was 60% higher (mean +/- standard deviation, 1372.5 +/- 108.3 mg) than that of bupivacaine (852 +/- 75.2 mg) (P < 0.001). There were no significant differences in the numeric rating scale scores and motor impairment.

CONCLUSIONS

In male patients, lumbar epidural administration of ropivacaine 0.2% after retropubic prostatectomy does not appear to provide benefits over bupivacaine 0.125%. Moreover, in view of the significantly higher drug requirements, general statements focusing on the favourable therapeutic index of ropivacaine may require critical analysis, at least during epidural administration.