Anesthesia Neurotoxicity

The ongoing concern continues, albeit somewhat controversial, that general anesthesia may be neurotoxic. This observational study on over 60 year olds found elevated Neurofilament Light and Tau for 6 hours and remaining high at 48 hours after surgery. They are both markers of neuronal damage. Correlation with clinical outcome would require further studies but clearly the entire area of potential anesthesia neurotoxicity, particularly in the developing infant and toddler brain, as well as in the elderly, will remain an important sphere of research and concern.


Lumbar Puncture & Dual Anti-Platelets

While not a study on spinal anesthesia, the Mayo Clinic review on lumbar puncture is relevant. They found no cases of spinal hematoma in 100 cases of LP in the presence of dual anti-platelet therapy. The study is small and retrospective, and the need for diagnostic puncture may possibly (pending further studies) be very important and justify the risk; an overwhelmingly strong absolute indication for spinal anesthesia is not so evident, and this small review is unlikely to change anesthesia cautious practice.



Further NAP6 Allergy & Anesthesia Insights

Teicoplanin over 16 tines culprit antibiotic in allergic reaction – twice other antibiotics. It seems to be a UK thing in terms of practice.

Test doses don’t serve any real purpose.

Since most anaphylaxis occurs within 5-10 mins a suggestion is to administer before anesthesia induction.

B-Blockers and ACEIs as well as older sicker patients and those with coronary artery disease have more hypotension and do worse.

Obese patients figured highly in mortality cases.

Hypotension is the presenting sign in half. Most severe cases may not show skin rash. Bronchospasm more an initial feature of Succinylcholine, which is also responsible for twice the anaphylaxis rate of non-depolarizing agents. Rocuronium leads the latter pack, followed by Atracurium and Mivacurium. No cases with Vecuronium or Cisatracurium.

There is a potential and debated relationship between Rocuronium allergy and Pholcodine, an opioid cough suppressant especially used in Australia which could sensitize subjects.

Chlorhexidine identified as responsible agent in 9%, often presenting with hypotension that is delayed and missed as diagnosis.

Fluid and epinephrine are the go to treatments not steroids and antihistamines which only play a corollary role. Sugammadex is not at this point an evidence based treatment for Rocuronium allergy. CPR was not started in many cases when it should have been.

Patent Blue dye (used in sentinel node locating in breast surgery) also a significant allergy culprit.

blog link


Oxygen and Wound Infection

A few studies suggested that using high oxygen  concentrations during and after surgery lowered surgical site infection rate. The World Health Organization has recommended FiO2 of 0.8 during and for many hours after surgery to help reduce wound infection. This is totally at odds with the increasing evidence of harm from hyperoxia and many anesthesiologists are reducing oxygen concentrations during surgery (apart from potential difficult airways). The WHO position seems simplistic and reductionist and a critique of their recommendation is found  here


Restrictive Fluids in ERAS Harmful?

RELIEF Trial finds an increased risk of acute kidney injury in the most restrictive fluid protocols in abdominal surgery. They advocate “modestly liberal” fluid regimes. This is a surprise and counter to current regimes of Enhanced Recovery after Surgery (ERAS)

The issue is more nuanced depending on oral intake and how oliguria and hemodynamic perturbation is managed but the overall message seems to be that  ultra restrictive regimes need not necessarily dictate practice at the expense of the kidneys


nejm editorial


Clinic vs Ambulatory Blood Pressure

An important study from general medicine that impacts us in our pre-admission service. Always seeing patients who say their hypertension is only when they come to hospital – white coat hypertension. This, and it’s opposite – masked hypertension (even more) is shown to be associated with mortality and cardiovascular assessment and advice should be so tailored.

“Ambulatory blood-pressure measurements were a stronger predictor of all-cause and cardiovascular mortality than clinic blood-pressure measurements. White-coat hypertension was not benign, and masked hypertension was associated with a greater risk of death than sustained hypertension“.

nejm link