British journal of anaesthesia
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Randomized Controlled Trial Comparative Study
Effects of positive end-expiratory pressure/recruitment manoeuvres compared with zero end-expiratory pressure on atelectasis during open gynaecological surgery as assessed by ultrasonography: a randomised controlled trial.
Why is this important?
Although we have moved beyond routinely using high tidal volumes in favour of ’protective ventilation strategies’ the specifics of what is protective and what improves outcomes is controversial. Previous trials have struggled to demonstrate post-operative respiratory benefits from protective strategies.
What did they do?
In this small randomised controlled trial, Généreux et al. investigated whether intraoperative PEEP (7 cmH2O) and recruitment manoeuvres (RM) q30min would reduce atelectasis post-extubation. Using ultrasound to measure intraoperative and post-operative atelectasis gives their study greater flexibility than other studies using CT scanning, generally considered the gold standard for atelectasis measurement.
And they found...
Among 34-85 yo women undergoing open gynae-oncology surgery >2h duration, there was no post-extubation difference in atelectasis whether receiving PEEP/RM or zero PEEP.
Not so fast
There was however less intraoperative atelectasis among the protective ventilation group, supporting the common use of PEEP and RM to improve oxygenation during surgery. Additionally, they specifically excluded morbidly obese women (BMI > 40 kg/m2), an increasingly common demographic at risk of ventilation challenges.
Nonetheless this study adds to the evidence that current protective ventilation strategies do not actually reduce post-operative respiratory complications.
Be smart
One interesting observation was the large amount of inter-patient variability, the researchers noting:
“...this heterogeneity highlights the need to dynamically monitor lung aeration changes and personalise our delivery of mechanical ventilation in the perioperative setting.”
As with many perioperative interventions, the benefits may in fact lie in the personalisation of our care for each individual patient.
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Multicenter Study Observational Study
Use of a train-of-four ratio of 0.95 versus 0.9 for tracheal extubation: an exploratory analysis of POPULAR data.
The prospective observational European multicentre cohort study (POPULAR) of postoperative pulmonary complications (NCT01865513) did not demonstrate that adherence to the recommended train-of-four ratio (TOFR) of 0.9 before extubation was associated with better pulmonary outcomes from the first postoperative day up to hospital discharge. We re-analysed the POPULAR data as to whether there existed a better threshold for TOFR recovery before extubation to reduce postoperative pulmonary complications in patients who had quantitative neuromuscular monitoring (87% acceleromyography). ⋯ A post hoc analysis of patients receiving quantitative monitoring of neuromuscular function suggests that postoperative pulmonary complications are reduced for TOFR > 0.95 before tracheal extubation compared with TOFR > 0.9.
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Randomized Controlled Trial Multicenter Study Comparative Study
Effects of oxygen on post-surgical infections during an individualised perioperative open-lung ventilatory strategy: a randomised controlled trial.
In the context of optimal, individualised lung ventilation, high inspired oxygen does not reduce surgical infections compared with conventional FiO2.
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Randomized Controlled Trial Comparative Study
Comparison of the effects of perineural or intravenous dexamethasone on low volume interscalene brachial plexus block: a randomised equivalence trial.
There is no clinically significant difference in the duration of low-dose interscalene block between perineural and intravenous dexamethasone.
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Randomized Controlled Trial
Effect of intravenous dexamethasone on the anaesthetic characteristics of peripheral nerve block: a double-blind, randomised controlled, dose-response volunteer study.
Intravenous dexamethasone at all studied doses did not prolong median nerve block.
pearl