Intending to deliver with labour epidural analgesia and then receiving a labour epidural is associated with slightly lower rate of postnatal depression.
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).
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.
Programmed Intermittent Epidural Boluses delivered by a commerically-available epidural pump, did not improve outcomes over continuous epidural infusion other than a lower incidence of motor block.
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:
- 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.
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.
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.
Incivil behaviour by surgeons in a simulated operating room crisis undermines anaesthesia trainee performance across all domains.
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.
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.
Dig deeper with other articles collected in Anesthesia technique and cancer recurrence.
Regional anaesthesia-analgesia (paravertebral block + propofol) does not reduce breast cancer recurrence or chronic pain when compared to volatile anaesthesia (sevoflurane).
This thorough review of the global epidemiology of perioperative hypersensitivity (POH), reflects our increasing awareness that anaphylaxis varies geographically.
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.
Anaphylaxis mortality was generally ~4% (UK, France, USA, Japan), although Western Australian data estimated a lower range of 0-1.4%.
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.
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.
Read Florvaag & Johansson’s seminal article The Pholcodine Story for an intriguing story of geographic POH differences.
Perioperative hypersensitivity reactions vary greatly between countries both in incidence and causative agents.
Although rare (~1 in 10,000 via NAP6 although varies by region) perioperative anaphylaxis is likely under-reported.