Pharmacology

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

 

B-Lactam (Penicillin) Allergy

A review of the subject provides some analysis and guidance. Salient points include the epidemic of over diagnosis – most patients don’t remember why they had penicillin or what kind of reaction they had. Some studies have shown as little as 1% true allergy in patients labelled as penicillin allergic. Many receive Penicillin subsequent to an “allergic” reaction. Other studies have shown waning and disappearance of allergies over time. Cross-reactivity to cephalosporins in the population is probably near 1% and not 10% as once reported.

Using alternative antibiotics risks increasing resistance and C  Difficile / VRE infections

While there are differences in structure of side chains, as a general guide they recommend proceeding with agents like Cefazolin where s previous reaction was mild and skin only. In major reactions or Stevens-Johnson syndrome  it is advised to avoid all B-Lactams including penicillins, cephalosporins, monobactams and carbapenems.

link

 

Epinephrine Bolus in Pediatric Hypotension

A retrospective review of the use of bolus epinephrine (up to 1mcg/kg) in the PICU for temporary control of hypotension as may occur during intubation, peri-arrest or shock. While efffective in restoring blood pressure, questions remain as to its myocardial effects in vulnerable patients, and this as well as dosing differences and calculation error concern makes it unlikely to change Anesthesia practice of utilizing Phenylephrine or Ephedrine in such scenarios. (Compare the studies on Norepinephrine bolus during Cesarean – most are not ready for that change yet!).

link

 

Melatonin and agonists in ICU

There has been little convincing evidence of Melatonin benefits in ICU. In this review of a Japanese study, the use of a Melatonin receptor agonist – Ramelteon – was associated with a reduced incidence and duration of delirium and a tendency to shorter duration of stay. A very small study that clearly needs replication in a larger setting to address the huge problem of delirium.

link