Questions · Transversus Abdominis Plane (TAP) Blocks
7 questions, 0 approved. Approve them one at a time — a quiz shows nothing you have not.
Recall — derived from a kept point
A procedure-specific meta-analysis of six randomised trials in 568 patients compared transversus abdominis plane block with thoracic epidural analgesia in colorectal surgery. Beyond pain scores, list the recovery and safety outcomes on which the block came out ahead, and state where the two were equivalent.
Answer: Pain control was comparable at rest and on movement. The block came out ahead on 24-hour and total opioid consumption, time to ambulation, urinary catheter duration, and the incidence of sensory disturbance and postoperative hypotension. When laparoscopic surgery was the only approach, the block additionally shortened time to first flatus and lowered the incidence of postoperative nausea and vomiting. The two were equivalent on 48-hour opioid consumption, on postoperative nausea and vomiting overall, and on hospital stay.
The advantages here are almost all downstream of what the epidural does to sympathetic tone and to the bladder — earlier walking, earlier catheter removal, less hypotension. In a minimally invasive operation those are the outcomes that decide the pathway, not the pain score.
Source claim: Pooling six randomised trials with 568 patients undergoing colorectal surgery, transversus abdominis plane block gave comparable pain control to thoracic epidural analgesia with lower 24-hour and total opioid consumption, shorter time to ambulation and urinary catheter time, and lower incidence of sensory disturbance and postoperative hypotension, while 48-hour opioid consumption, postoperative nausea and vomiting and hospital stay were similar; when laparoscopic surgery was the only surgical approach employed, the transversus abdominis plane block gave the additional benefits of shorter time to first flatus and a lower incidence of postoperative nausea and vomiting compared with thoracic epidural analgesia.
Hamid HKS et al., Transversus abdominis plane block versus thoracic epidural analgesia in colorectal surgery: a systematic review and meta-analysis, Langenbecks Arch Surg 2021
recall · CA-2 · phrased by llm
Thirty women having elective caesarean section under spinal anaesthesia received bilateral ultrasound-guided transversus abdominis plane blocks after wound closure with ropivacaine 2.5 mg/kg diluted to 40 ml, and venous ropivacaine concentrations were sampled for four hours. Report the peak concentrations, when they occurred, and what symptoms were seen — then say what that means for how you dose this block.
Answer: The mean peak total ropivacaine concentration was 1.82 micrograms/ml (SD 0.69) and occurred 30 minutes after injection; the highest concentration in any patient was 3.76 micrograms/ml, at 10 minutes. Three patients reported symptoms of mild neurotoxicity, and their mean peak level was higher at 2.70 micrograms/ml (SD 0.46). What the study establishes is that a bilateral block — a large volume of local anaesthetic injected between the muscles of the abdominal wall, at a weight-based dose — can raise plasma ropivacaine to concentrations that may be associated with neurotoxicity. So the quantity to think about is the total dose across both sides rather than the dose per side, systemic absorption rather than needle placement is what limits it, and the patient is worth watching through the first half hour when the peak arrives. The authors also note pharmacokinetic reasons why pregnancy may increase susceptibility to local anaesthetic toxicity — background they cite for studying this population, not something this study measured.
The three symptomatic patients differed from the rest in plasma level; the study reports nothing to suggest they differed in technique. A fascial plane block has no aspiration test that protects you from absorption, and the mean peak arrived at about 30 minutes — often after the patient has left theatre.
Source claim: In 30 women receiving bilateral ultrasound-guided transversus abdominis plane blocks with ropivacaine 2.5 mg/kg diluted to 40 ml after elective caesarean section, the mean peak total ropivacaine concentration was 1.82 micrograms/ml (SD 0.69) at 30 minutes post-injection, the maximum concentration detected in any patient was 3.76 micrograms/ml at 10 minutes post-injection, and three patients reported symptoms of mild neurotoxicity with a higher mean peak level of 2.70 micrograms/ml (SD 0.46). The authors describe the block as injecting a large volume of local anaesthetic between the muscles of the abdominal wall, note that there are pharmacokinetic reasons why pregnancy may increase susceptibility to local anaesthetic toxicity, and conclude that the block can result in elevated plasma ropivacaine concentrations which may be associated with neurotoxicity.
Griffiths JD et al., Symptomatic local anaesthetic toxicity and plasma ropivacaine concentrations after transversus abdominis plane block for Caesarean section, Br J Anaesth 2013
recall · CA-2 · phrased by llm
The point with one number taken out. No model wrote any of this: the stem is the sentence you reviewed, minus a digit, and the paper it came from is named beneath it.
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
Questions only — nothing here asserts anything, which is why a model is allowed to phrase them. Where no model was reachable these are the level defaults.