POISE showed that for every 1000 patients receiving metoprolol, 15 were prevented from suffering a myocardial infract, 3 from requiring cardiac revascularization along with 7 new cases of atrial fibrillation, but at a cost of causing an excess 8 deaths, 5 strokes, 53 hypotensive events and 42 episodes of bradycardia.
The harm associated with perioperative beta-blockade, at least in the form of non-titrated extended-release metoprolol, is greater than the demonstrated benefit. For every two cases of myocardial infract avoided there is one excess death.
Perioperative metoprolol in at-risk patients undergoing non-cardiac surgery reduced major cardiovascular adverse events but increased mortality.
Multiple labour epidural top-up boluses, caesarean section urgency or care by non-obstetric anaesthetists increase risk of failed epi anaesthesia.
Retrospective studies show that a single anesthesia exposure before age 3 may undermine language acquisition and abstract reasoning, and exposure to two or more anesthetics before age 2 almost doubles the risk of attention-deficit hyperactivity disorder, although in both cases causality has not yet been established.
Anesthesia neurotoxicity may affect the developing human brain, however methodological challenges limit the conclusiveness of current evidence.
Nerve block duration may be extended by adrenaline, clonidine, dexmedetomidine, dexamethasone, and possibly midazolam, tramadol and magnesium. Other than adrenaline there is however no longterm data demonstrating safety. Intra-articular adjuvant benefit has been shown for tramadol, magnesium, dexmedetomidine, clonidine, ketamine, ketorolac and morphine, but the evidence is not strong enough to support routine use.
Barreveld et al. show that LA administered either IV or via block; before, during or after surgery, significantly reduces postoperative pain and opioid consumption.
- Total knee arthroplasty (femoral, sciatic and lumbar plexus b., single-shot or continuous)
- Total hip arthroplasty (continuous lumbar plexus; intra-articular LA)
- Knee arthroscopy (single-shot lumbar plexus; IA LA; single-shot femoral nerve ± sciatic).
- Arthroscopic shoulder surgery - interscalene b., single-shot or continuous. IA is not beneficial.
- Hand & forearm surgery - axillary b. offers analgesic benefits only on day of surgery.
- TAP block is beneficial for laparoscopic, open appendectomy, abdominal surgery, cesarean section, and TAH.
Intravenous lidocaine is efficacious and may be a suitable alternative to regional anesthesia when contraindicated or not performed.
Nerve blocks in general have a beneficial analgesic effect, regardless of whether pre- or post-incision, and are superior to intra-articular LA.
Monitoring neuromuscular blockade with TOF at the eye muscles (orbicularis oculi) results in a 5 times greater risk (adjusted odds ratio) of postoperative residual curarization (PORC) than monitoring at the hand (adductor pollicis) when PORC is defined by TOFR < 90% using acceleromyography.
PORC was nonetheless common in both groups, occurring in 52% and 22% respectively.