Article Notes
- Completion of checklist items expected for the crisis.
- Ratings for vigilance, decision-making, teamwork and communication.
- Whether performance was consistent with level expected of anaesthesiology resident.
Why is this relevant?
Anaesthetists and anesthesiologists have long worried about the recall of labouring women when presented with risk-benefit discussions prior to epidural analgesia or receiving anaesthesia for cesarean section.
This UK survey of over 900 women across 28 Greater London hospitals explored recall of this antenatal and intrapartum information, along with maternal satisfaction.
What did they find?
There was very little recall of receiving either thorough labour analgesia information (9%) or anaesthesia for CS (12%) provided during the antenatal period.
During the interpartum period, fewer than two-thirds (62%) recalled receiving thorough information during labour before insertion, and less than one-third (28%) before Caesarean section anaesthesia.
13% of women did not recall receiving any information before epidural insertion.
These are concerning findings in a modern era where patient autonomy and informed consent are prioritised, and more so where informed decision making may contribute to a positive birth experience.
Interestingly, verbal information appeared best recalled (OR 5.9 to 20.7 across different categories), although this is counter to past studies showing superiority of written information.
Be clear
Because the 28 hospitals contributing to the survey had large practice differences in how antenatal anaesthetic information was provided, it is difficult to determine whether the provision of information or recall itself is the problem.
Take-home...
Regardless of the cause, a large proportion of pregnant women did not recall being adequately informed before epidural analgesia or caesarean anaesthesia. This needs to be improved.
Daniel Jolley
Why is this interesting?
Lidocaine/lignocaine has been increasingly used intra- and perioperatively as an analgesic adjunct, with further research suggesting a potential neuroprotective effect. Cognitive decline is a common problem following cardiac surgery (40-50%), with lidocaine potentially offering a simple and safe intervention to reduce this complication. Past studies have showed conflicting results.
What did they do?
This Duke University team randomized 478 cardiac surgery patients across multiple centres to lidocaine intraoperatively (1 mg/kg bolus then decreasing infusions across 2.9 / 1.5 / 0.6 mg/kg/h over 48 hours) or blinded control. Cognitive function was assessed at 6 weeks and 1 year.
They found...
No difference in cognitive deficit between lidocaine infusion and saline control at either 6 weeks or 1 year.
Be smart
Intravenous lidocaine infusion remains relatively safe, practical and is still likely a useful analgesic adjunct. Similar to magnesium, which has been shown to be neuroprotective in premature infants but not adult cardiac patients, the problem for lidocaine may well be context rather than physiological benefit itself.
Daniel Jolley
Relevance?
Although anti-hypertension therapies are the domain of primary care physicians, because of their widespread use they are common medications for hospital patients. Previous studies have shown that nocturnal anti-hypertensive dosing improves BP control, although have not addressed major cardiac outcomes.
This 10-year, large, multicenter RCT demonstrates benefit of evening medication dosing that has implications perioperatively.
The study...
The Hygia Project randomised 19,084 patients (x̄=61y 56%♂ 34%♀) to take their anti-hypertensive medications (≥1) either at bed-time or on awakening. Patients were followed for a median 6.3 years, routinely using 48h ambulatory BP monitoring at each follow-up review.
They found that...
Patients taking anti-hypertensives in the evening experienced better BP control and 45% lower rates of major cardiovascular outcomes, including CVD death, infarct, coronary revascularisation, heart failure and stroke.
Interestingly the progressive decline in sleeping SBP during the study was the strongest predictor of cardiovascular risk, stronger than traditional risk markers such as age, gender, DM, CKD, cholesterol or even smoking!
Practice changing?
This is a significant finding from a large, high-quality study. It confirms the benefits of nocturnal dosing, also likely (though unconfirmed) to have intraoperative and perioperative benefits compared with morning dosing.
Daniel Jolley
Why the fuss?
Acute renal injury is a common post-operative complication among high-risk patients and after major surgery, particularly cardiac and major vascular surgery, as is relevant to this study. The clinical relevance of ischaemic preconditioning continues to be controversial.
Even mild post-operative acute kidney injury (AKI) is associated with a wide range of poor perioperative outcomes, and current interventions have struggled to reduce such risk.
What is remote ischaemic preconditioning (RIPC)?
In an effort to protect an at-risk end organ from ischaemia (eg. heart, brain, kidneys), RIPC cyclically induces ischaemia in a remote site (typically an arm using an NIBP cuff). This activates physiological protective mechanisms against hypoxia and reperfusion injury in the target organ. It is cheap, easy and safe.
RIPC as a technique is based upon Murray’s 1986 observations of dog LAD arteries.
Although remote ischaemic (pre)conditioning has been demonstrated in animal models, human studies have been contradictory.
What was done...
This Shanghai research team randomised 130 patients undergoing open aortic arch replacement to receive either remote ischaemic preconditioning (4x 5-min-up 5-min-down) or sham preconditioning.
They found...
Fewer patients demonstrated renal injury at 7 days in the treatment group (55% vs 74%, ARR 95% CI 2-35%), in addition to shortening mechanical ventilation duration (18 vs 25 hours).
Practice changing? No
Although this study has shown a marked reduction in AKI in a uniquely very-high-risk group, as a sole small single-centered study it can barely be applied to the actual study population, let alone generalised to other high-risk groups.
Even when AKI in the control group was a massive 74%, the confidence interval for absolute risk reduction (2-35%) is so wide as to cast doubt on the credibility of this result.
Go deeper:
Meybohm (NEJM 2015), Hausenloy (NEJM 2015), and Menting (Cochrane 2017) failed to show any significant renoprotective effect from RIC in other high-risk groups.
Daniel Jolley
Why is this relevant?
Sore throat following endotracheal intubation is common (reported in up to 68%), and along with postoperative nausea & vomiting, negatively impacts postoperative well-being.
Small studies have previously suggested that IV dexamethasone reduces sore throat due to intubation. It is thought this occurs by reducing mucosal inflammation at the point of tracheal cuff contact, the presumed aetiology of the majority of post-ETT sore throat.
Kuriyama and Maeda conducted a systematic review and meta-analysis of 15 RCTs totalling 1,849 patients.
And they found?
Preoperative dexamethasone IV (~4-10 mg across the studies) reduced the incidence of sore throat by almost 40% (RR 95% CI 0.51-0.75) and mean severity by 1.1 (SMD 95% CI 1.8-0.3).
Take-home...
Given the established effectiveness of preoperative dexamethasone to safely reduce post-operative nausea and vomiting, this meta-analysis affirms another important indication for the routine use of dexamethasone in intubated patients who do not have contraindications to steroid use.
Daniel Jolley
What’s so special about Programmed Intermittent Epidural Boluses?
Programmed Intermittent Epidural Bolus (PIEB) techniques have been advocated as an improvement over continuous epidural infusions because of the potential to optimise local anaesthetic spread through the epidural space.
Other studies have suggested that PIEBs result in reduced local anaesthetic consumption, less motor block, fewer instrumental and cesarean deliveries and improved maternal satisfaction – however these have often occured in research environments and with equipment not representative of typical clinical practice.
What did they do?
This Duke University team randomized 120 parturients to epidural ropivacaine 0.1% + fentanyl 2 mcg/mL delivered either as PIEB (6mL q45min) or continuous infusion (8 mL/h). All subjects had access to patient controlled epidural analgesia (PCEA) for breakthrough pain, used as the marker of analgesia efficacy. The study used the commercially-available CADD Solis pump.
And they found...
There was no difference in PCEA volume between groups, or in any secondary outcome (physician interventions, hypotension, pain scores, satisfaction, duration, or delivery mode), EXCEPT for a greater motor block seen with the continuous infusion group (50% vs 28% Bromage < 5).
Bottom-line
This (relatively small) study did not find significant improvement in labor experience or outcome with PIEB using commercially available epidural pumps, although the reduction in motor blockade may
Pause for thought...
The big challenge with identifying benefit from PIEB techniques is that it introduces even more epidural variables (pump type, bolus volume, frequency, concentration & flow rate, lockouts, background infusions...) making it very difficult to compare the conlficting results of PIEB studies.
Read more in the growing Programmed Intermittent Epidural Bolus for Labour Analgesia article collection.
Daniel Jolley
Why is this important?
Medical crises are high stress, and do not always bring out optimal behaviour in clinical teams. Although progress has been made to improve operating room cultures, the specific consequences of ‘incivil’ behaviour in anaesthesiology have not been previously defined.
Katz and team set out to identify the effect of incivility on performance during a simulated operating room crisis (intraoperative haemorrhage), noting that multiple surveys show the ubiquity of incivility in surgical and anaesthetic environments.
“Incivility is a potential source of interpersonal conflict and a latent threat to effective communication...” – Katz et al.
What did they do?
Across three institutions, 76 anaesthesiology residents were randomised to crisis simulation encounters with or without incivility (“rude, dismissive or aggressive behaviour”), expressed by the simulated surgeon through scripted dialogue and demeanour.
“The experimental group’s surgeon was portrayed as impatient, but not overtly intimidating (ie, actors were instructed not to use inappropriate language, become physically intimidating or scream). The control group’s surgeon was courteous and the interactions straightforward.”
Participant performance was independently assessed in three ways:
Exposure to incivility lowered performance across every metric
Also notable, exposed participants believed that the environment negatively effected performance, even though self-reported performance assessment was comparable between groups.
91% of the control group were rated as performing at their expected level, but only 64% of the incivility-exposed group. Quality of decision making was particularly vulnerable to incivility, as were vigilance, communication and teamwork.
Take-home message
Professional conduct and civil behaviour is another important non-technical skill, consequential to crisis performance. We should already appreciate that incivility has no place in the high-stakes environment of an operating theatre, if for no other reason than it’s not civil.
Anaesthesiologists should also be aware of how their behaviour may effect the performance of their colleagues.
Daniel Jolley
What makes this a landmark study?
Since Exadaktylos’ (2006) extraordinary retrospective study showing a 30% reduction in breast cancer recurrence with a regional analgesia technique, we have been anxious to learn whether anaesthetic choice my impact cancer outcome.
Various in vitro studies suggested plausible explanations for how opioids and volatiles could promote cancer recurrence, although quality evidence remainded missing.
The Breast Cancer Recurrence Collaboration has filled this gap, setting out to answer this question with an international, multicenter, randomised controlled trial.
What did they do?
Over 12 years 2,132 women were enrolled and ranomised to either paravertebral block & propofol, or sevoflurane. Some in the paravertebral group were exposed to sevoflurane when required (17%), and did receive intraoperative fentanyl, although roughly half as much on average as the volatile group.
And they found?
There was no difference in cancer recurrence rate or persistent wound pain between groups. Even when analysing only patients who received no sevoflurane (83% of regional group) no difference was identified.
This does not mean that a paravertebral technique offers no benefit: it almost eliminated the need for volatile anaesthesia, reduced opioid demand and reduced post-operative nausea & vomiting – all positive outcomes. But it did not reduce cancer recurrence.
Be smart
This result cannot be generalised beyond breast cancer to more invasive, stress-inducing cancer surgery (eg. prostatectomy, pneumonectomy). Our knowledge of perioperative factors that depress host defences (surgical stress, volatiles and opioids) are still relevant when we consider how anaesthetic choices may contribute to improving patient outcomes.
Explore further...
Dig deeper with other articles collected in Anesthesia technique and cancer recurrence.
Daniel Jolley
This thorough review of the global epidemiology of perioperative hypersensitivity (POH), reflects our increasing awareness that anaphylaxis varies geographically.
Incidence
Reported incidence ranges from 1 in 18,600 to 1 in 353, although NAP6 (UK) and French studies independently estimate life-threatening anaphylaxis at 1 in 10,000.
Mortality
Anaphylaxis mortality was generally ~4% (UK, France, USA, Japan), although Western Australian data estimated a lower range of 0-1.4%.
Causal agents
Implicated agents commonly include neuromuscular blocking drugs (1st or 2nd commonest in most studies), although the higher incidence seen with specific NMBDs (eg. Sux and Roc) appears to occur in some regions but not others. Pholcodine has been implicated as causative in these regional differences.
Sugammadex has increasingly been implicated as a cause of POH, though notably also with regional variation. A dose-related effect has also been reported.
Antibiotics are an increasingly common cause of POH, in particular β-lactams. Nevertheless, ‘pan-β-lactam allergy’ is probably rare, and some examples like cefazolin, have limited cross-reactivity.
“Cefazolin does not share an R1 and R2 group with any other β-lactam...”
Latex POH is declining, while chlorhexidine is increasing (9% in NAP6, with significant regional variability), albeit often as a ‘hidden’ precipitant.
Surgical dyes (patent blue V, isosulfan blue, methylene blue) are also increasingly common causes of POH (4th most common in NAP6 (~1 in 7,000), 3rd in France).
Less common POH causes include povodine-iodine and colloids.
Hypnotics, local anaesthetic, aprotinin, protamine and NSAIDs are very uncommon-to-rare causes of POH. Opioids are sometimes implicated via the MRGPRX2 receptor, although true opioid IgE-mediated hypersensitivity is very rare.
Bottom-line
The wide geographic variations in anaphylaxis incidence and causation reveal a complex interplay of genetics and environment, along with our evolving understanding of the complexity of anaphylaxis.
Go deeper...
Read Florvaag & Johansson’s seminal article The Pholcodine Story for an intriguing story of geographic POH differences.
Daniel Jolley
“Cyclodextrin is frequently used in foods and cosmetics because it can change the physical properties of various compounds by their encapsulation within the cyclic structure. The average person is thought to ingest about 4 g of gamma-cyclodextrin per day from food. ... even people who have never received sugammadex may be sensitised by food and cosmetics.” (Mertes 2019)
Daniel Jolley