Article Notes
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It would also be feasible for recording, analysis and reporting to occur entirely at the bedside on a smartphone. ↩
- Coloured drug labels with barcodes.
- Computerised drug crosscheck.
- Computerised allergy and drug expiration alerts.
- Re-organised anaesthesia workplace, focusing on the drug administration workflow.
- Prefilled syringes for: calcium chloride, ephredrine, fentanyl, lidocaine, magnesium sulphate, metaraminol, midazolam, neostigmine, and pancuronium.
- Automated computerised anaesthetic record.
- Webster (2001): The frequency and nature of drug administration error during anaesthesia
- Merry (2001): A new, safety-oriented, integrated drug administration and automated anesthesia record system
- Webster (2004): A prospective, randomised clinical evaluation of a new safety-orientated injectable drug administration system in comparison with conventional methods.
- Whether SGA placement is detrimental or beneficial, compared with basic airway support, and;
- Whether there is any difference if the arrest occurs at the scene or in the confines of an ambulance.
What’s so interesting?
De Carvalho and co. show that pre-operative voice analysis can be predictive of difficult laryngoscopy.
I’d never thought about that...
The authors describe how different frequency components and acoustic qualities of the voice are, at least partly, determined by the shape and size of different anatomical areas of the vocal tract. By analysing the most intense frequencies (voice formants) within the voice spectrum they were able to correlate components with difficult laryngoscopy, namely Cormack & Lehane grade 3 or 4.
The practicalities
During pre-anaesthetic assessment, 467 elective general surgical patients were asked to pronounce each of the five vowels, corresponding to base phonemes. This was recorded on a smartphone and then later processed and analysed on a laptop computer.1
They found...
A model using voice ‘formants’ could reliably predict difficult laryngoscopy with a ROC-AUC of 0.761 (ie. 76% probability that it correctly classifies a patient as difficult or not). When combined with the modified Mallampati this improved to 92%.
The big picture
While interesting, it’s worth remembering that using voice formants (76%) did not perform as well as modified Mallampati alone (87%), and that this performance is also surprisingly much better than those from the most recent Cochrane meta-analysis (2018) of bedside airway assessment. Over 133 studies the Cochrane review reported a summary sensitivity of only 53% and specificity of 80% for the modified Mallampati (vs 100% and 75% respectively for this study).
Although this is an interesting and novel new test, it’s just not that simple... Screening for an uncommon outcome using tests with imperfect sensitivity and specificity is already problematic, but doubly so when we are not always certain which outcome we should be screening for (laryngoscopy, intubation, ventilation, oxygenation...).
As an airway screening test, voice analysis is both different and also more of the same.
Daniel Jolley
See also the reply letter from Audra Webber and Melissa Kreso: Informed Consent for Sugammadex and Oral Contraceptives: Through the Looking Glass.
Daniel Jolley
The authors suggest a possible revision of anaesthesia consent, such as:
"You may receive medications during your anesthetic that could interfere with the effectiveness of oral contraceptives. If you are using oral contraceptives, consider alternative methods of birth control for 7 days following your anesthetic." This disclosure would cover potential interactions with sugammadex, antibiotics, and other medications.
Daniel Jolley
Note the authors: “So long as neostigmine and glycopyrrolate are available and not prohibitively expensive, we should make a point in our practice to not use sugammadex for rocuronium reversal in women of childbearing age in situations where neostigmine and glycopyrrolate will have equal effectiveness.”
Daniel Jolley
Why?
Although often used to manage chronic pain acutely, the longer-term benefits of ketamine infusions remain uncertain. Despite this there has been significant growth in using ketamine infusions to treat chronic pain, rationalised by ketamine’s expected effect to reduce central sensitisation.
What?
This meta-analysis identified a small benefit for up to two weeks after a ketamine infusion, although little evidence of longer-term benefit. There appears to be a dose-response effect, suggesting greater efficacy with high-dose ketamine infusions.
The underlying problem...
Most research on ketamine infusions focuses on perioperative analgesia. Trials invetsigating ketamine infusions for chronic pain are universally small, lack standardisation and are often low quality.
This meta-analysis unfortunately does not add clarity to the question of whether ketamine infusions have long-term benefit in chronic pain syndromes. Clinicians will continue to need to judge indication on a case-by-case basis...
Daniel Jolley
The researchers performed multiple cross-sectional surveys of three years of US anesthesiology trainees, from their first year of clinical anesthesia training to a year after qualification. They surveyed the anesthesiologists for burnout, distress and depression.
Burnout, distress and depression were worryingly common (51%, 32% and 12% of residents), although self-reported availability of workplace resources to manage burnout & depression, and perceived work-life balance were protective, roughly halving odds of each outcome.
Having strong social supports was also associated with lower rates of depression and burnout, although not distress.
Both working more hours each week and having larger student loan debt were associated with depression and distress, although not burnout.
Females, although only making up 37% of respondents, were more likely to suffer from burnout and depression. International medical school graduates were in contrast less likely.
The take-home message...
Burnout, distress and depression are common among anesthesiology trainees and newly qualified anesthesiologists. Workplace support, efforts to maintain work-life balance, maintaining social supports and limiting working hours are modifiable factors that have protective effects.
Daniel Jolley
An interesting and thought-provoking study, even with its flaws.
The authors concluded that system changes surrounding anaesthetic drug delivery reduce medication error.
A ‘care bundle’ approach was taken to improve drug safety through system design and human factors considerations:
But the problems...
No randomisation, no blinding, observational study, completely voluntary use of the safety system and self-reporting of errors...
Were the improvements due to the intervention, or simply a greater interest and priority given to anaesthetic safety? (Would it matter?)
In only 15% of anaesthetics was the new system (voluntarily) used, and thus may represent anaesthetists more motivated to prioritise medication safety over convenience or convention.
Finally error is being used (not unreasonably) as a surrogate marker for patient harm. (Although the authors did try to sneak in... “a non-significant reduction (p=0.055) in the harm attributable to drug administration error” 🙄)
Final word of caution
Even this quite impressive system was not immune to error. There were 19 cases of violation of the video and/or audio crosscheck before drug administration. Automated safety systems are obviously no panacea.
Additionally, although there was an observed reduction in all drug errors, there was no reduction specifically in drug substitution error.
Nonetheless a refreshing and novel approach to anaesthetic drug safety, beyond the typical admonishment to just be safer.
More on the system used:
Daniel Jolley
What is this?
This Korean study investigated 6,620 out-of-hospital cardiac arrests (OHCA) witnessed by emergency medical providers, covering a four year period of the Korean OHCA registry. They looked at outcome among those receiving advanced airway intervention, comparing arrest at scene to arrest in the ambulance.
Why is this interesting?
Past studies have suggested better OHCA outcomes when a supraglottic airway (SGA) is used rather than endotrachial intubation (ETI). We also know that repeated advanced airway attempts are detrimental, and that airway intervention can interrupt CPR.
What was not known is:
And they found:
There was no benefit from advanced airway intervention (SGA or ETI) for EMS witnessed out-of-hospital arrest – and in fact there was an associated worse neurological outcome for in-ambulance OHCA when the airway was instrumented compared to any other group.
Don’t be hasty...
Although the authors reasonably describe the ways in which providing advanced airway interventions in the confines of an ambulance may impede other resuscitation, thus worsening outcomes, it may also be that a patient who still arrests despite receiving EMS care in the back of an ambulance is by definition at risk of worse outcomes despite medical care.
Nevertheless, at worst this retrospective observational study suggests there is no benefit of advanced airways in OHCA.
Bonus...
The authors also provide an interesting overview of the Korean emergency medical system, servicing 50 million people in urban and rural areas. This is an enlightening insight into how one country has structured its EMS service.
Daniel Jolley