Pre-Operative Fasting

A narrative review surveys recent changes in approaches to preoperative fasting. It particularly focuses on clear fluids and the evidence from clinical as well as gastric ultrasound studies, endorsing 2 hour fasting for clear fluids, and the more recent adoption of 1 hour clear fluid fasting in Pediatrics. Clinical scheduling and logistic issues have however still led to unnecesssry prolonged fasting. 

The topic of carbohydrate loading is also discussed, usually as 50g maltodextrin polysaccharide in 400 ml – twice the evening before surgery and within 2 – 4 hours of surgery. While Insulin resistance is diminished and small improvements in enhanced recovery have been reported, further evidence on outcome is needed, as well as the risk/benefit in diabetic patients. 

Other risk analysis (with possible gastric ultrasound support) may be needed in those with reflux, GI obstruction, esophageal disease or pregnancy, among other individual cases. 

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Ultrarestrictive Opioid Policy

This study in gynecologic oncology surgery implemented a policy whereby patients undergoing ambulatory or minimally invasive surgery (laparoscopic or robotic approach) were not prescribed opioids at discharge unless they required more than 5 doses of oral or intravenous opioids while in the hospital, and patients who underwent a laparotomy were provided a 3-day opioid pain medication supply at discharge.

Importantly the reduction in opioid use was not accompanied by an increase in pain scores. Such policies mirror the use of opioid free (or sparing) anesthetic techniques which are increasingly employed. 

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Anesthetic Medication Pharmacokinetics at Extremes of Body Weight

A great primer on the factors which influence medication handling in malnourished or obese patients and how they affect bolus, re-dosing and infusion. A discussion of issues like doses, volume of distribution, hepatic blood flow, lipid solubility, renal function, total vs. lean body weight, protein binding etc. 

Ideal body weight and lean body weight are often used but a notable exception is Succinylcholine which is usually recommended as mg/kg total body weight. 

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Another resource including dosing recommendations in the obese link

Weekly Medical and Health News

A more flexible and patient focussed Canadian guideline on breast cancer screening  link

New CMA Code of Ethics  link

Roux-en-Y gastric bypass leads to the greatest weight loss, but sleeve gastrectomy has the lowest 30-day adverse event rate  link

First Nations children in Canada show higher pain indicators but see pain specialists less  link

Radical prostatectomy reduces mortality among men with clinically detected localized prostate cancer  link

Fentanyl surpasses Heroin as deadliest drug in US  link

Childhood trauma/abuse associated with psychosis in adolescents and young adults  link 

Johnson & Johnson reportedly knew for decades that there was asbestos tainting in their Baby Powder – now the cancer link lawsuits may make more sense  link

UK chain restaurants provide meals as bad nutritionally as fast food – including way more calories!  link

Infection Control in Anesthesiology

The Society for Healthcare Epidemiology of America has issued expert guidelines for infection control in Anesthesiology, a subject often shown to performed suboptimally. The ASA has summarized the recommendations and include the full link:

  • Hand hygiene should be performed, at a minimum, before aseptic tasks, after removing gloves, when hands are soiled, before touching the anesthesia cart, and upon room entry and exit. The authors also suggest strategic placement of alcohol-based hand sanitizer dispensers.
  • During airway management, the authors suggest the use of double gloves so one layer can be removed when contamination is likely and the procedure moves too quickly to perform hand hygiene. The report also recommends high-level disinfection of reusable laryngoscope handles or adoption of single-use laryngoscopes.
  • For environmental disinfection, the guidance recommends disinfecting high-touch surfaces on the anesthesia machines, as well as keyboards, monitors and other items in work areas in between surgeries, while also exploring the use of disposable covers and re-engineering of the work surfaces to facilitate quick decontamination in what is often a short window of time.
  • IV drug injection recommendations include using syringes and vials for only one patient; and that injection ports and vial stoppers should only be accessed after disinfection.

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STOP-BANG Questionnaire and Outcome

The STOP-BANG questionnaire is a validated tool for Obstructive Sleep Apnea screening but this study sought to validate it as a predictor of complications after non-cardiac surgery. 

It had modest construct validity (correlation with ASA status, Revised Cardiac Risk Index, Charleston Comorbidity Index). However its predictive validity was not confirmed in that it did not predict postoperative mortality, hospital length-of-stay, or cardiac complications.

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Cerebrovascular Autoregulation and Delirium

Delirium occurs in up to 50% of patients after cardiac surgery.  Previous studies have shown an association between impaired cerebrovascular autoregulation during cardiac surgery and delirium. This study found an association between impaired cerebrovascular autoregulation, measured by near‐infrared spectroscopy, and delirium in the early postoperative period. The postulation is whether individualized, cerebrovascular autoregulation‐guided blood pressure management during cardiopulmonary bypass can reduce postoperative delirium and stroke. 

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Cricothyroid Membrane and Head Position

It has been recommended to mark the cricothyroid membrane with or without ultrasound pre-induction in an anticipated difficult airway to facilitate a surgical airway in an unfolding emergency. 

This study shows that it better to do this with the neck fully extended as the position significantly moves as the head is put in this recommended position for surgical airways. It also opens the membrane more to facilitate the advises size 6 tracheal tube insertion. 

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