Hypotension Prediction Index did no better than treating at a MAP of 73

The edition in brief

Today's anaesthesia edition opens on cannabis. A single-centre US cohort of 341,199 adults found that non-medical cannabis use was associated with about 6.9 µg/kg/min more propofol during sedation and a small rise in volatile MAC, with daily users needing the most; effects were smaller than earlier reports suggested. A laboratory study of eight local anaesthetic and adjuvant mixtures known to form microscopic crystals found the drug concentration in solution stayed constant over 13 hours, and the precipitates in lidocaine-bicarbonate mixtures were pure local anaesthetic. The FDA recorded a supplement to a generic buprenorphine application, an administrative step rather than a new indication or safety finding. The pearl covers asking about cannabis at preoperative assessment. The edition closes on a randomised trial of 100 adults undergoing major non-cardiac surgery with arterial lines: management triggered by the Hypotension Prediction Index was not superior to treatment triggered whenever MAP fell to 73 mmHg or below, on time-weighted hypotension, vasopressor dose, length of stay or 30-day mortality, suggesting much of the index's reported benefit may come from treating earlier.