Article Notes
- Nausea & vomiting (NNH 10 each)
- Urinary retention (NNH 7)
- Pruritus (NNH 4)
- Respiratory depression (NNH 38-59 for IT morphine 0.05-0.5 mg)
- Successful catheter insertion on first attempt in 47%
- Satisfactory and uncomplicated analgesia in 55%.
- Dural puncture in 4%.
- Subdural catheterization in 4%.
There has been some observational evidence that a greater depth of anesthesia, as measured by BIS, may be associated with an increase in post-operative mortality. In particular the association of the "triple low state" (low BIS, low volatile-ET, low MAP) with post-operative mortality is worrying.
Completion of the Balanced Anaesthesia Study Group’s large RCT looking at this issue however brings us as close to a final word as we may expect. Short et al. (2019) showed no difference in 1-year mortality for older patients undergoing major surgery, whether they received a deep (BIS target 35) or light (BIS target 50) general anaesthetic.
It is likely that earlier observational studies were showing the consequences of intraoperative hypotension resulting from anaesthetic depth, rather than anaesthetic depth itself.
A case report describing the first-reported, successful and safe use of Xenon-based anesthesia in an MH-susceptible 31 year old male.
The authors conclude that this case, along with previous investigation of Xe in susceptible-swine animal models and in vitro human muscle biopsy testing, show that Xenon is likely safe for use in MH-susceptible individuals.
Bartlett and Hutaserani published the first description of the intravenous use of lignocaine for postoperative pain management in 1961.
"THE SEARCH for a nondepressant, long-acting drug to control postoperative pain has gone on for many years. Like many other institutions, ours has run the gamut of drugs as they have been released: nupercaine-in-oil, intravenous procaine, efocaine, intravenous alcohol, d-tubocurarine-in-oil, etc. All have had their drawbacks."
The researchers investigated a progressive range of administration routes and dosages, ultimately reaching 1000 mg lignocaine in 1L IVF given over the duration of surgery. 302 patients receiving intravenous lignocaine were compared to matched controls, finding:
"...during the first 3 postoperative days 83 per cent of the patients who received Xylocaine experienced either no pain or 1+ pain (soreness only) as contrasted with 25 per cent of the controls."
Intravenous lignocaine also dramatically reduced post-operative opioid consumption.
Another group (N=60) received 500 mg lignocaine into the rectus muscles after laparotomy, improving no-pain or 1+ pain incidence to 95%.
There is some evidence supporting the benefit of perioperative intravenous lignocaine/lidocaine infusion in both laparoscopic and open abdominal surgery.
The strongest evidence supports both improved analgesia and reduction in nausea, with weaker evidence suggesting faster improvement in GIT function and earlier discharge from hospital.
Safety data is reassuring but far from conclusive due to the small size of most studies.
This meta-analysis investigated the benefits and risks of intrathecal morphine and fentanyl, concluding that:
Intrathecal morphine prolongs post-operative analgesia on average more than 8 hours, but at cost of:
Intrathecal fentanyl prolongs post-operative analgesia on average almost 2 hours, but at a cost of pruritus (NNH 3).
A case report and brief literature review examining the efficacy and complications of labor epidural analgesia in patients with Harrington rods after scoliosis surgery.
Ho, Ngan Kee & Chung reviewed 52 reported cases in the literature showing:
Lowest success rates, highest repeated-attempts and highest complication rates (DP 8%, failure 8%, poor analgesia 55%) occurred in those with a spinal surgery scar extending below the epidural insertion point.
Articles of interest relevant to labor epidural analgesia, both specifically focusing on obstetric epidurals and more peripherally relevant to obstetric labor analgesia.
An interesting narrative focusing on John Snow's successful introduction of anesthesia, particularly chloroform, to obstetric practice in the 19th century.
The paper begins with a brief exploration of why James Young Simpson, arguably the first pioneer of obstetric anesthesia, failed to popularize this new technology when shortly thereafter Snow succeeded.