Intraoperative dexamethasone produces a small, though clinically insignificant post-operative analgesic benefit.
The incidence of systemic local anesthetic toxicity showed different risk profiles at different injection sites. In order of decreasing incidence of systemic toxicity events:
- Paravertebral – OR 3.62 [95% CI, 1.33–7.86]
- Upper limb — OR 1.75 [95% CI, 0.93–2.99]
- Lower limb — OR 0.24 [95% CI, 0.05–0.71]
- Trunk — 0.00 [95% CI, 0–0.94]
Of the 25,336 peripheral nerve blocks in the study, there were only 22 episodes of local anesthetic toxicity. 12 events occurred in the 20,401 PNBs performed with ultrasound guidance and 10 events in the 4,745 blocks performed without ultrasound.
The use of ultrasound for peripheral nerve blockade reduces the incidence of systemic local anesthetic toxicity by at least 65%, possibly 80%.
Important to note that the 9 studies included for meta-analysis (524 patients in total) were quite heterogenous: 7 performed under spinal anaesthesia and 2 under general; TAP performed using anatomical landmarks in 3 and ultrasound in 6; spinals used various doses of fentanyl and/or morphine; and the TAP blocks used ropivacaine (4), bupivacaine (4) or levobupivacaine (1). Post-operative analgesic regimes also varied.
Thus these findings should be cautiously applied to your local setting.
In patients not receiving intrathecal morphine, TAP block after caesarean section reduced opioid use at 6, 12 and 24 hours, along with nausea at 12h.
Intermittent intraperitoneal lidocaine at 50 mg/h reduces post-operative morphine consumption by almost 50% after open abdominal hysterectomy.
Intermittent intraperitoneal lidocaine at 50mg/h during open abdominal hysterectomy exerts analgesic effects via local mechanisms rather than central.
Dexamethasone provides effective PONV prophylaxis (NNT 3.7). There is however no benefit of an 8 to 10 mg IV dose over a lower 4 to 5 mg dose.
Meta-analysis of 10 RCTs totalling 633 subjects showed that while pain at rest following laparoscopic surgery was reduced by transverse abdominis plane block, early (0-4 h) pain was only moderately reduced (-2.4 cm) and late pain (24 hours) minimally reduced (-1.3 cm). Pain with movement was not significantly different between TAP blocks and controls.
TAP block reduced early and late pain at rest after laparoscopic surgery, though not pain with movement.