Femoral nerve block is better than PCA alone after total knee replacement, although comparison to local infiltration is unclear.
Even if beneficial, perioperative lignocaine infusions probably have no analgesic benefit beyond 24 hours post-operatively.
Post-operative cognitive problems are a growing worldwide concern, especially with our aging surgical population – but as this Cochrane review points out, we still don’t know the answers to even some simple questions, like ‘Is there a difference between TIVA and volatile anesthesia?’
Continue to watch this space...
Optimizing depth of anesthesia with a processed EEG (BIS, Entropy, or similar) in surgical patients over 60 yo is probably beneficial by reducing the incidence of post-operative delirium and cognitive decline.
Unlike dexmedetomidine sedation in the critical care setting, intraoperative dexmedetomidine does not reduce postoperative delirium.
Desflurane and propofol anesthesia are associated with similar incidence of post-operative delirium in the obese, elderly undergoing total knee replacement.
Neuraxial morphine does not have a protective effect on headache after unintentional dural puncture.
Why should you care?
Not only is venous cannulation a common procedure, but so is resultant thrombophlebitis – occurring in up to 75% of patients. This has important morbidity, patient-experience and economic consequences.
What does this study add?
Although many risk factors have been identified (insertion sterility, location, access technique, drug use, micro-particles, etc.), Villa and friends investigated whether in-line filters would reduce phlebitis incidence.
This modest, single-center trial randomized surgical patients between in-line filter (for 96 hours) or standard line, before anesthesia induction. Filter user reduced thrombophlebitis 13-fold at 48 hours, and at 96 hours sustained potency of 50% more of the cannulae.
What sort of filters did they use?
They used an 11 cm2 positively-charged 0.2 µm filter for fluid and most drugs, a 4.5 cm2 1.2 µm filter for propofol infusions, and a positively-charged 1.65 cm2 0.2 µm for opioid infusions.
The filters did slow gravity-fed infusion rates as they aged, however this was not clinically significant when using a peristaltic pump.
We should be better stewards of our patient's IV access. For short-term access <48h focus should be on technique and sterility, but for access needed for 48h or longer, an inline filter offers significant benefit with limited downside.
Finally some evidence to show the inaccuracy of palpation in rescue FON access! This will potentially change my practice. Now I'm more inclined to pre-site the CTM via ultrasound in patients with no necks prior to induction.
Accurately identifying the cricothyroid membrane is foundational for front-of-neck rescue of airway misadventure. Yet the very patients who are at risk of a cannot intubate, cannot oxygenate scenario (eg. obese, neck pathology) are also likely to make identifying the cricothyroid membrane (CTM) difficult.
Naveed and co. compared the accuracy of CTM palpation to ultrasound in a single-blinded randomized trial of 223 patients, with poorly defined landmarks, undergoing CT neck.
The ultrasound group showed a 10-time greater success in identifying the CTM (correct within 5 mm of actual; 81% vs 8%), along with a 5-times smaller mean distance from actual to estimated, than did the palpation group.
So what's the take home?
Given the wide-availability of ultrasound and it's acceptability to patients, any pre-induction marking of the CTM in an anticipated difficult airway should employ neck ultrasound in all but the most obviously-palpable necks.
In an emergent CICO situation, neck ultrasound likely has utility, though at the potential cost of procedural complexity and delay.