This month, in a stinging editorial, Professor Pandit argues a lack of rational data on theatre performance and efficiency make the NHSI report on operating theatres an almost worthless read. It is perhaps the claim that list over-runs are due to late starts or gaps between cases that will strike a chord with clinicians. He argues such claims are not backed by evidence and are at odds with existing literature. This editorial is a must read for all theatre staff and you can read a response from one of the report’s authors here.
Tranexamic acid has revolutionised the management of traumatic and non-traumatic haemorrhage following the publication of the landmark CRASH-2 and WOMAN trials. Whilst the peri-operative benefits of tranexamic acid are well documented, Patel et al. provide data on catastrophic drug errors that have arisen as a result of intrathecal administration. They identified 21 cases with a mortality rate of just under 50% (10 out of 21 cases). Of the remaining 11 cases, 10 required ICU admission for refractory convulsions and/or tachyarrhythmias with a high incidence of permanent neurological injury in survivors. Perhaps the most worrying (and disappointing) finding is that an ampoule error (i.e. not checking or reading the label, similar size ampoules) occurred in 20 patients. This is unsurprising, given the similarities shown in Figure 1. In the accompanying editorial, Palanisamy and Kinsella discuss potential causes of such errors and provide practically useful solutions to reduce the risk of such rare, but catastrophic errors, down to zero.
Figure 1. Similarity of tranexamic acid and bupivacaine ampoules.
Gastric ultrasound is becoming increasingly popular. Studies so far have used a variety of different participant positions to evaluate gastric volume using ultrasound, and the ideal position is unknown. Bouvet et al. address this by evaluating the effect of different patient positions and different bed angles on gastric ultrasound contents in healthy volunteers. They found the angle of the bed can significantly affect ultrasound performance, and a 45°angle performed the best to detect gastric fluid volume > 1.5 ml.kg-1. Nascimento et al., in a non-inferiority randomised trial of labouring women, observed that maltodextrin was cleared from the stomach faster than coffee with milk and orange juice. These studies add to the growing body of evidence suggesting gastric emptying and volume are not solely dependent on volume ingested and total calories, but also on other factors such as protein and lipid content and patient positioning. Mohta et al. carried out a randomised trial of 100 mg phenylephrine boluses versus 5 mcg noradrenaline boluses to treat maternal postspinal hypotension during elective caesarean section. They hypothesised that noradrenaline would be less likely to cause bradycardia, due its weak b-agonist chronotropic action. Results showed no difference in the primary outcome of bradycardia, but the total number of phenylephrine boluses required was, perhaps unsurprisingly, greater than noradrenaline. Interestingly, the umbilical artery pH, bicarbonate and base excess were lower in the noradrenaline group which could have been as a result of placental transfer, but the mechanisms and clinical implications of this requires further investigation.
Reducing the environmental impact of anaesthesia is a key strategic issue for the Association of Anaesthetists. Kennedy et al., in a quality improvement study, provide novel data on how a single episode of high fresh gas flow at the start of anaesthesia can have a significantly modifiable effect on overall gas flow and vapour consumption. The authors provide us with useful conceptual framework (Figure 2) that suggests we need to be more mindful of our gas flows during induction. Hade et al. modified an existing central line insertion checklist by recommending insertion depths and adding a picture of a chest radiograph with a traffic light coloured tick-box system to assist with post-insertion tip confirmation (Figure 3). They report an impressive reduction in line tip malpositioning, along with improvements in documentation of other components of the checklist such as sterility measures.
Figure 2. The three factors that are directly under the control of the anaesthetist that determine overall fresh gas flow (FGF) and vapour consumption: (1) the initial (high) FGF; (2) the duration of the initial FGF; (3) the FGF during the maintenance phase.
Figure 3. Central venous catheter checklist accompanied with the traffic light system.
Elsewhere, Luther et al., in a bench top study, observed that the brand of bougie, brand of double-lumen tube and size of double-lumen tube all influence the degree of bougie fragment shearing. This has implications for tube manufacturers who may consider specifying in advance which bougie could be safely used with their double-lumen tube. Dingley et al. investigated the effect of temperature control in different designs of emergency drug transport bags, which can have important consequences on the efficacy of emergency drugs. Gratz et al. successfully demonstrated the uptake of thromboelastometric-guided algorithms in emergency departments with no previous experience of such technology. Implementation of such algorithms has the potential to improve outcomes in patients with traumatic brain injury and suspected haemorrhage.
In our reviews section, Roth et al. performed an excellent and highly clinically relevant abridged Cochrane review on the beside accuracy of bedside tests for predicting difficult airways. They found that, although none of the current tests are well suited for detecting anticipated difficult airways, the upper lip bite test had the most favourable test accuracy properties with a sensitivity of 67% and specificity of 92%. In the accompanying editorial, Law and Duggan discuss the challenges of current airway assessment strategies, offer advice on what to screen for and how to act if difficulty is predicted and suggest directions for future research. Poldermans et al. found no evidence that perioperative dexamethasone increases the risk of developing wound infections. It did produce a transient increase in glucose levels by a mean difference on 0.7 mmol.l-1, but data were on patients without diabetes mellitus. Surprisingly very little evidence currently exists on glycaemic control in patients with diabetes who receive dexamethasone, but the results of a large trial (8800 patients) with stratification of diabetes status are awaited. Some of the issues around dexamethasone administration and diabetes are discussed in an editorial by Albrecht and Wiles. They primarily focus on the some of the key findings of a recent NCEPOD report which reviewed the care of patients with diabetes who underwent surgical procedures. The authors make a strong case for departments to have clinical leads for the perioperative management with diabetes, alongside better utilisation the existing expertise of diabetic nurse specialists and better recognition of inadequate diabetic control in the operating theatre.
Over on Anaesthesia Reports, we have two new cases – one on the use of high flow nasal oxygen in a high-risk obese patient requiring sedation in the prone position, and another on awake tracheal intubation for blunt airway trauma. We hope you enjoyed our most recent #FrontOfNeck TweetChat as much as we did. We were never really going to definitively settle the scalpel vs. cannula eFONA debate, but some of the associated discussions were fascinating! Finally, we look forward to seeing you at Association of Anaesthetists Trainee Conference in early July. Matt Wiles will be discussing evidence-based advances in trauma, Mike Charlesworth will be discussing contemporary mechanical circulatory support and Andy Klein will be presenting some of the best papers from Anaesthesia.
See you in Telford!
Professor Andy Klein and Dr Akshay Shah
#TheAnaesthesiaBlog 
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