Article Notes
- Sugammadex is still cost-prohibitive for many health systems.
- Although neuromuscular reversal is demonstrably better than for neostigmine, sugammadex use does not obviate the need for neuromuscular monitoring (Kotake 2013: Reversal with sugammadex in the absence of monitoring did not preclude residual neuromuscular block).
- Sugammadex is an important option to consider in a CICO crisis, but it is not a ‘Get Out of Gaol Free’ card (Kyle 2012: A persistent 'can't intubate, can't oxygenate' crisis despite rocuronium reversal with sugammadex).
- Sugammadex is now the leading cause of perioperative anaphylaxis in Japan, and we have likely underestimated the risk of sugammadex hypersensitivity. (see: Sugammadex anaphylaxis: all that glitters?).
- True aortal compression is relatively uncommon (Higuchi 2015, Lee 2012).
- Caval compression is probably near-universal, but also usually not improved by a mere 15 degree tilt. (An impractical 30 degrees is more likely required for meaningful impact!) (Palmer 2015).
- Caval compression probably has limited haemodynamic or fetal consequences in the fit, well, term parturient (Higuchi 2015; Lee 2012).
- Judicious use of vasopressor infusions may obviate the need for traditional uterine displacement (Lee 2017; Farber 2017).
- Hepatic failure
- Neurological disease
- High-neostigmine dose > 60 mcg/kg
- Metastatic solid tumour
- Female sex
- Less than 120 min between NMBD administration and extubation
- Aminosteroid NMBD
- BMI more than 35
- Absence of nurse anaesthetist (CRNA)
- Having an experienced surgeon
What's the story here?
Growing evidence points to significant anti-depressant effects of several anesthetic agents, including ketamine, nitrous oxide, propofol and isoflurane. These may provide avenues for use as novel antidepressants or lead to development of new agents, supplanting other therapies such as ECT.
Why is this important?
Major depression and its consequences contributes to significant disease burden worldwide. Depression prevalence is increasing globally, with one third suffering treatment-resistant depression, unresponsive to modern antidepressant drugs.
Ketamine appears to produce both a fast antidepressant and antisuicidal effect, persisting for up to 1 week. The effect appears dose-responsive in the 0.1 to 0.75 mg/kg range.
Isoflurane when administered to achieve burst suppression (1.5-2 MAC) may have antidepressant effects in 75% of those treated, and achieved full remission in 50% in one 2013 study, comparable to ECT but with fewer cognitive side effects.
N2O use in one small pilot study resulted in depression improvement, likely through similar mechanisms as ketamine. Similarly, propofol-induced burst suppression has also shown an antidepressant effect similar in magnitude to isoflurane.
Bottom line: Several anesthetic agents appear to offer significant antidepressant benefits, which may lead to more mainstream use and supplant ECT. Anesthesiologists will be need to be aware of these effects as they become involved in their provision.
Daniel Jolley
Why is this important?
6% of the world's population has diabetes mellitus, making it one of the most common perioperative comorbidities. Withholding oral-hypoglycaemics pre-op is common, but worsens glucose control and so may increase post-op complications.
What did they find?
Ambulatory patients who had their metformin and/or sulphonylurea OHG agents continued perioperatively had better glucose control.
Be cautious as this was a relatively small study, and not adequately powered to compare hypoglycaemia rates or (ridiculously) rare complications such as lactic acidosis. Additionally, no investigation was made of post-op complications, instead using glucose control as a surrogate outcome.
Bottom line
It's probably safe and beneficial to continue metformin and sulphonylureas perioperatively in those having ambulatory day-surgery with normal renal function.
Daniel Jolley
Important caveats to temper our sugammadex enthuasiasm...
Daniel Jolley
Is the conventional assumption that left-lateral tilt and uterine displacement avoids aortocaval compression during Caesarean section actually valid?
50 years of assumed orthodoxy is challenged by studies showing that:
Time to change practice then?
Not quite yet...
Daniel Jolley
Case report from Yamaguchi, Japan describing a confirmed sugammadex anaphylaxis in a 50kg woman receiving 4mg/kg sugammadex.
Notably, follow-up skin prick testing strongly suggests #1 hypersensitivity to free sugammadex molecules, rather than the sugammadex-rocuronium complex, and #2 hypersensitivity appears to be dose-related.
Daniel Jolley
Why is this important?
First, because it identifies new novel risk factors for residual neuromuscular block (experienced surgeon, non-CRNA anesthesia provider...) and secondly, because the subtext reveals the lengths our specialty goes to avoid simply monitoring using qualitative NMB monitoring (TOFR)!
What did they find?
Rudolph et al. created a REsidual neuromuscular block Prediction Score (REPS) using Massachusetts General PACU data, applying covariate analysis to identify 10 risk factors, some more surprising than others:
Be smart:
These risk factors might suggest patients who need more careful monitoring, but you will probably be better off just using qualitative monitoring routinely. The utility of REPS itself is only modest with NPV & PPVs of 85% each.
The other takeaway is that rNMB is still demonstratably common, occurring in 20% of this cohort!
Daniel Jolley
While there is both utility and some interesting insights from the LAS VEGAS risk score research, it also seems to have largely confirmed that higher risk patients, having more invasive or major surgery, and those who misbehave intraoperatively are more likely to experience postoperative pulmonary complications...
Daniel Jolley
Chris Tan
Although there remains much conflicting evidence, largely of a low-quality observational nature, the highest quality evidence to date refutes assertions that epidural fentanyl reduces breastfeeding rates.
Notably Lee et al.’s 2017 RCT of over 300 women showed no effect of epidural fentanyl up to 2 mcg/mL and successful maternal breastfeeding up to 6 weeks.
Daniel Jolley
The association of anesthesia in the sitting beach-chair position with intra-operative stroke, continues to be controversial. Although some studies have identified this as a risk, it is still a rare complication, albeit devastating.
Expert opinion suggests intra-arterial blood pressure monitoring is best practice, but most importantly with consideration for actual cerebral perfusion pressure given the sitting position.
Some research suggests regional anaesthesia, possibly combined with spontaneous ventilation GA (rather than relaxation GA with IPPV) offers unique benefits that better maintain cerebral oxygenation, although the exact difference is unclear.
Similarly, the benefit and role of non-invasive cerebral perfusion monitoring has not been conclusively shown, although it appears logical that it may offer benefit in these patients.
Case studies of patients suffering cerebral ischaemia under beach-chair, do point to combinations of poor intra-operative blood pressure management and possibly pre-existing mild cardiovascular disease (eg. hypertension) as contributing to some degree.
Daniel Jolley