September 2025

British Journal of Anaesthesia

Submitted August 2025 by Dr Ayaka Omori

Read by 3 Journal Watch subscribers

This narrative review serves as an update on the use of remimazolam in paediatric population.

The introduction of remimazolam is a notable development in hypnotics in the past two decades.

Remimazolam has advantages because of its predictable pharmacokinetics due to rapid onset (1-2 mins), short duration (5-20 mins), predictable metabolism (elimination half-life 5-10 mins) with minimal accumulation (context-sensitive half-life likely short and stable).

It also promises a remakrable safety profile, with the absence of adverse events such as hypotention, respiratory depression, or bradycardia. It has already established antagonist flumazenil.

Remimazolam could be a safer alternative in high risk population where haemodynamic and respiratory stability is paramount.

With these advantages and despite its growing use in adult anaesthesia and sedation, clinical data and experience with remimazolam in the paediatric population remains limited, especially in neonates and infants. Recently, Cai et al. provided dosing estimates for children, reporting the ED₅₀ and ED₉₅ values. Based on their findings, the recommended dosing range is 0.45–0.60 mg/kg for children aged 1–6 years and 0.35–0.45 mg/kg for those aged 6–12 years.

However, the authors describe several gaps remain in our understanding of remimazolam use in children, and outline the following priorities for further research:

• Safety, efficacy and cost-effectiveness are yet to be evaluated in the broader paediatric population. Potential heterogeneity has been reported in remimazolam metabolism due to variability of carboxylesterase 1 activity, which plays a key role in the drug metabolism. Safety for vulnerable cohorts such as neonates also need to be examined.

• Comparative trials against commonly used agents such as propofol and midazolam will be necessary to establish clinical superiority or equivalence.

• The development of a robust target-controlled infusion (TCI) model for paediatric use, along with a deeper understanding of remimazolam’s interactions with opioids and neuromuscular blocking agents, would further bolster remimazolam's utility in the clinical sphere.

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Pediatric Anesthesia

Submitted August 2025 by Dr Su May Koh

Read by 3 Journal Watch subscribers

This simulation-based study examined the effect of a Paediatric Regional Anaesthesia Time-out Checklist training for pediatric anaesthetists and trainees. Not surprisingly it found that checklist training and having a shared-mental model led to an increased number of safety items performed before a simulated anesthetic block scenario.

The Society for Paediatric Anesthesia Quality and Safety Committee developed a 14 item Paediatric Regional Anesthesia Time-Out Checklist and in the process of evaluating and testing the checklist designed a study to observe the behaviours of 11 attending anesthesiologists and resident dyads in 132 simulated scenarios.

There were 12 scenarios developed of which in 4 scenarios, medical staff were expected to decline performing the block due to a safety concern (programmed error) in the scenario (eg coagulation issues or excessive local anesthetic doses). The scenarios were designed to encompass types of errors previously reported in the literature making them more relevant. Medical staff in pairs (attending/consultant anesthesiologist with resident/trainee) completed 6 medium fidelity simulation scenarios (two of which had a programmed error). This was followed by completion of a survey and then checklist training. After the training, the pairs completed 6 further medium fidelity simulation scenarios (again with two scenarios having a programmed error). This was followed by a debrief and survey completion.

Each scenario was expected to last 2-4 minutes and each attending and trainee were given different stem cards and expected to communicate. No specific instructions were given about who should initiate the checklist time-out and the scenario ended when the block needle was inserted. Video recordings of the scenarios were performed and scored for safety items achieved and whether the decision to perform the block or abort the block was recorded.

Results

132 simulated scenarios were performed by 22 anesthesiologists. In terms of the study’s primary outcome, they found that a greater number of safety items were completed after training on the Pediatric Regional Anesthesia Time-Out Checklist for each of the 11 pairs (p=0.002). Of note 78% of safety items studied were performed after training and 41% of safety items were performed prior to training. The authors also found that the team’s choice to perform or abort the regional anesthetic occurred (as expected) more often after the Checklist training (p=0.001). Of note prior to checklist training in 3 scenarios, teams chose to perform the regional anesthetic block despite a programmed error (safety concern). Two of the scenarios involved a patient with a low platelet count having a neuraxial block where before checklist training the medical staff elected to proceed with the block. Interestingly after the checklist training no teams chose to perform the blocks in scenarios where there were safety concerns/programmed errors.

The checklists were overall favourably rated for usability and design and participants thought favourably of checklists in the medical setting.

Commentary

This study is interesting as it examines checklist testing using pairs of anesthesiologists namely an attending and a trainee, promoting additional team interaction and a shared mental model. The authors commented that the number of times that each pairing had worked together previously varied thus potentially showing the utility of the checklist even for teams of variable interpersonal familiarity. A possible limitation includes the learning effect in a simulated environment with a relatively small sample size. The authors also commented that this was a single site study in a centre with a high safety culture and where checklists were widely accepted, this may not be true of all paediatric centres.

Take-Home Messages

Even though serious adverse events are rare in pediatric regional anesthesia, potential complications such as wrong-sided blocks, local anesthetic dosing errors may be prevented by the use of checklists and clear communication. A block time-out with a checklist is now an expected and important part of ensuring patient safety. This may be particularly true in pediatric anesthesia where the majority of our blocks are performed in anesthetised patients.

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Pediatric Anesthesia

Submitted August 2025 by Dr Eamonn Upperton

Read by 6 Journal Watch subscribers

This retrospective cohort study examines axillary arterial lines placed in PICU patients to compare their safety profile with radial arterial lines, and provides some baseline data to support their use as a second line option.

Methods

The authors performed an EMR review of all documented axillary arterial lines placed on PICU patients under age 18 between 2007 and 2023 at a tertiary hospital, yielding 306 patients.

These patients were age-matched with patients who received a radial arterial line during the same time period, for 306 controls.

The electronic notes were reviewed for demographic information, data relating to the line and its complications, and PICU mortality.

Analysis

The limitations imposed by the retrospective cohort study design make it challenging to directly compare the two techniques:

• The axillary arterial line is described as an 'alternative access site' chosen by the clinician when catheterisation of the radial artery was not possible.
• The axillary artery cohort was therefore not randomly chosen, and likely consists of sicker patients with more difficult arterial access
• The radial artery cohort was matched by similar age but otherwise randomly selected from the electronic record

The cohorts were clearly quite different at baseline, as demonstrated by the 12% mortality rate in the axillary group compared with 2% in the radial group. It is therefore difficult to make conclusions about the safety of one technique compared with the other, except to say that one might expect a higher rate of complications in the axillary artery cohort commensurate with their higher severity of illness.

The primary outcome was the rate of vascular complications in each cohort, which the authors defined as treatment or consult for vascular injury or thrombosis.

• One patient in the axillary artery group experienced a documented vascular complication (0.33%). This was described as an ischaemic upper limb, and was treated sucessfully with a brachial plexus nerve block, systemic tPA, and heparin infusion.
• No patients in the radial artery group experienced a vascular complication

Secondary outcomes included duration of catheter use, reasons for catheter removal and catheter replacement.

Axillary catheters were retained longer than radial (presumably relating to the difficulty in siting them in the first place!), and otherwise had similar removal and replacement rates.

Discussion

This paper has a somewhat narrow definition of a 'vascular complication', requiring that a patient underwent treatment or surgical assessment for thrombosis or arterial injury. These events are rare but clinically significant, and would be at the forefront of a clinician's mind when choosing their approach.

It is possible that other studies with a broader view of what constitutes a 'vascular complication' may uncover more subtle or transient differences between axillary and radial artery techniques, but a focus on the more devastating outcome seems reasonable given the axillary approach's second-line status.

Given the higher severity of illness in the axillary catheter group, the absence of an excess of severe vascular complications should reassure a clinician considering the axillary artery approach as a second-line option.

Take home message

The purpose of this paper is to help the clinician faced with an unwell paediatric patient with difficult arterial access, and provides some reassurance that an axillary arterial line is a feasible option in those challenging circumstances.

A key decision point for clinicians faced with impossible distal artery access in paediatrics might be to choose between upper and lower limb - with femoral being the more traditional choice. The comparative safety of femoral versus axillary arterial access is not examined by this paper, though a referenced single-centre study does show a lower incidence of vascular compromise (defined as 'any perfusion abnormality') for axillary versus femoral arterial lines in paediatric cardiac patients (6.2% vs 19.9%, respectively); the same paper described 4 major arterial injuries in the femoral group (0.37%, n=1068) and 0 in the axillary group (n=195).

While the findings are largely reassuring, this paper's excellent description of management for the single ischaemic limb complication in the axillary group (and brief mention of retrograde cerebral embolism) serves to temper enthusiasm for more routine use of proximal artery techniques.

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