Questions · Interscalene Brachial Plexus Block
9 questions, 0 approved. Approve them one at a time — a quiz shows nothing you have not.
Recall — derived from a kept point
Seventy patients having major shoulder surgery were randomised to a continuous interscalene catheter placed with its tip either inside the brachial plexus sheath or immediately outside it, midway between C5 and C6, all receiving the same ropivacaine bolus and infusion. Give the rates of hemidiaphragmatic paresis on the first postoperative day and say what it cost analgesically.
Answer: Paresis on postoperative day 1 was 41% with the intrafascial tip and 15% with the extrafascial tip. No analgesic cost could be measured: the investigators were unable to detect a difference between the groups in forced vital capacity, forced expiratory volume in 1 second, or rest pain scores, which were a median of 3 on a 1-10 scale in both (p = 0.93). With 70 patients that is a failure to detect a difference rather than a demonstration that none exists. The authors' conclusion is that routine placement of the catheter tip inside the sheath is not supported.
Moving the tip outside the sheath more than halved the rate of paresis while the trial could detect no difference in rest pain — the trade the study was designed to look for. The familiar explanation, that the local anaesthetic still reaches the plexus and simply has further to travel towards the phrenic nerve, is an account offered for that result and not something the trial measured. Note also that the intrafascial rate here was 41%, not 100%: a low-volume continuous infusion is a different exposure from a large single-shot bolus.
Source claim: In 70 patients randomised to intrafascial or extrafascial catheter tip placement for continuous interscalene block, hemidiaphragmatic paresis on postoperative day 1 occurred in 41% (95% CI 25-59%) of the intrafascial group and 15% (95% CI 5-32%) of the extrafascial group (p = 0.01); the investigators were unable to detect a difference between the groups in forced vital capacity, forced expiratory volume in 1 second, or rest pain scores (numerical rating scale 1-10: intrafascial 3, 95% CI 2-3; extrafascial 3, 95% CI 2-4; p = 0.93), and concluded that their results do not support routine placement of the catheter tip within the brachial plexus sheath.
Albrecht E et al., Reduced hemidiaphragmatic paresis with extrafascial compared with conventional intrafascial tip placement for continuous interscalene brachial plexus block: a randomized, controlled, double-blind trial, Br J Anaesth 2017
recall · CA-2 · phrased by llm
This randomized trial found that for ASA I or II patients undergoing humeral surgery with an interscalene block, low-dose esketamine (___ mg/kg bolus, 0.15 mg/kg/h infusion) improved postoperative day 1 recovery quality and caused less sedation and heart rate reduction than dexmedetomidine.
Answer: 0.2
This randomized trial found that for ASA I or II patients undergoing humeral surgery with an interscalene block, low-dose esketamine (0.2 mg/kg bolus, 0.15 mg/kg/h infusion) improved postoperative day 1 recovery quality and caused less sedation and heart rate reduction than dexmedetomidine.
Comparison Between Low-Dose Esketamine and Dexmedetomidine on Postoperative Recovery Quality Among Patients Undergoing Humeral Trauma Surgery in Interscalene Brachial Plexus Block: A Randomized, Double-Blind, Controlled Trial · PMID 40351348
recall · CA-2 · phrased by derived
This randomized controlled trial found that adding ___ mg of perineural dexamethasone to ropivacaine for interscalene brachial plexus block in shoulder arthroscopy patients did not significantly prolong the duration of analgesia compared to ropivacaine alone.
Answer: 5
This randomized controlled trial found that adding 5 mg of perineural dexamethasone to ropivacaine for interscalene brachial plexus block in shoulder arthroscopy patients did not significantly prolong the duration of analgesia compared to ropivacaine alone.
Postoperative Analgesia Effect Evaluation of Perineural Dexamethasone Plus Various Doses of Ropivacaine in Interscalene Brachial Plexus Block: A Randomized Controlled Trial · PMID 40401460
recall · CA-2 · phrased by derived
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Open prompts
How does your plan change if the patient is not optimised?
open · CA-2 · phrased by derived
What is the physiology behind what we just did?
open · CA-2 · phrased by derived
Talk me through the trade-off you made there.
open · CA-2 · phrased by derived
What would make you abandon this plan and do something else?
open · CA-2 · phrased by derived
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