Removing retracted and suspicious studies completely reverses the WHO 2016 recommendation for high FiO2 to reduce surgical infections. The scourge of academic misconduct continues!
Erythropoietin further reduces red blood cell transfusion in surgical patients, beyond iron therapy alone.
MAC-awake of sevoflurane is modestly lower in patients with end-stage renal failure compared with normal controls.
Intravenous dexamethasone at all studied doses did not prolong median nerve block.
Perioperative high inspired oxygen concentrations do not reduce surgical site infections – and may possibly increase infection incidence.
High inspired oxygen concentrations intraoperatively do not reduce surgical site infections, and may potentially have detrimental effects.
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.
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.
No difference in post-operative atelectasis was observed after non-abdominal surgery for patients having PEEP either maintained or withdrawn before emergence.
In the context of optimal, individualised lung ventilation, high inspired oxygen does not reduce surgical infections compared with conventional FiO2.
There is no clinically significant difference in the duration of low-dose interscalene block between perineural and intravenous dexamethasone.