Peripheral Nerve Blocks and Acute Compartment Syndrome: What to do?
Stephanie Pan MD and Ban Tsui Dip Eng, BSc(Math), BSc(Pharm), MSc(Pharm),MD, FRCP(C), PG Dip Echo
I’m fairly certain that for most of you who take call, it sometimes feels like every kid coming to the OR has been to a trampoline party. The question that always arises: “Can you use a peripheral nerve block in patients at risk of developing acute compartment syndrome (ACS)?” Most of the orthopedic surgeons that I know take a very conservative approach and don’t allow them in their patients. But is this evidence based? When I saw this adult article by Samet etl al.1 in Anesthesia and Analgesia, I knew it would be a great article for the PAAD and perhaps for a future SPA meeting.
I asked one of the giants in the fields of pediatric neural blockade and ultrasonography, Dr. Ban Tsui of Stanford University and his colleague Dr. Stephnie Pan to review this article for us. Myron Yaster MD
But first a word from Dr. Glaucomfleckin
Original article
Ron E Samet, Arissa M Torrie, Svetlana V Chembrovich, Barys V Ihnatsenka. Pro-Con Debate: Peripheral Nerve Blockade Should Be Provided Routinely in Extremity Trauma, Including in Patients At Risk for Acute Compartment Syndrome. Anesth Analg. 2023 May 1;136(5):855-860. PMID: 37058722
Severe pain resulting from extremity trauma and subsequent surgery poses significant challenges in pain management. Inadequate pain control impairs quality of life and increases morbidity and healthcare costs.2 Peripheral nerve blocks (PNBs) are effective in relieving limb pain but are underutilized due to concerns of masked acute compartment syndrome (ACS), potential limb loss, and unnecessary suffering. In today’s PAAD, we summarize a pro-con debate on peripheral nerve blockade in adult extremity trauma1 from a pediatric perspective. Using the article by Samet et al. as our guide we will discuss four distinct categories: (a) analgesic efficacy; (b) risk stratification; (c) acute pain service resource; (d) ischemic transmission pathway.
(a) Analgesic efficacy
PNBs offer superior opioid-sparing analgesia and reduce the neuro-cognitive effects associated with multimodal medications such as opioids, ketamine, benzodiazepines, and gabapentinoids. Improved mental clarity theoretically enhances the recognition of early signs of ACS. However, opponents of PNBs emphasize the risk of masking disproportionate pain in ACS, particularly when a dense block is used. Multimodal analgesic approaches offer pain relief while minimizing neurologic compromise in the affected limb.
Customized block density in pediatric patients is feasible based on weight-based calculations. However, achieving the right balance between analgesia and block density requires reliable patient feedback, and there is no literature to guide pediatric dose adjustments. Even so, the classic five Ps (pain, paresthesias, paralysis, pallor, pulselessness) are late presentations of ACS and highly unreliable in children.3 The three As (increasing anxiety, agitation, and analgesic requirement) may be a better alternative metric.4
(b) Risk stratification
ACS risk varies depending on patient demographics and injury mechanisms. The use of PNBs should align with ACS risk. For example, the ACS risk differs between a frail elderly woman who sustains a distal tibial fracture from a ground-level fall and a muscular teenage male with a high-impact injury to the distal tibia resulting in extensive tissue and vascular injury. Prophylactic fasciotomies performed during the initial surgery also present little risk of ACS. Although well-defined institutional risk stratification protocols are well-intentioned, ensuring consistent education of the multi-disciplinary team remains challenging and often lacks uniformity.
Teenagers are amongst those at the highest risk for ACS.5 However, the pediatric orthopedic literature recommends aggressive fasciotomy as children have more robust muscle recovery, fewer wound complications, and decreased need for split-thickness skin grafts than adults.6
(c) Acute pain service resource
Dedicated regional anesthesia and acute pain services (APS) provide consistent PNB analgesia, minimize missed PNB placements, deliver value-based care, and offer follow-up services.7 In patients with extremity trauma, APS clinicians can provide more consistent risk stratification, expertise in modifying PNB and implementing multimodal analgesics, and enhanced ACS monitoring protocols. However, resource limitations hinder the establishment of full-time APS teams in many adult healthcare centers.
Likewise, not all children’s hospitals have an APS team. Among those that do, the collaboration between the APS and regional anesthesia teams may vary, which can complicate provider response times.
(d) Ischemic transmission pathway
ACS-induced ischemic pain may travel through different anatomical pathways (perivascular sympathetic fibers) and not with motor and sensory nerves targeted by PNBs.8, 9 This potentially explains why some patients report disproportionate pain despite a dense PNB. However, this theory is yet to be proven, and the impact of PNB techniques on these pathways remains uncertain.
There is also no evidence to suggest anatomical differences in pain transmission between children and adults. While this research shows promise, the nuances in pain transmission may be more of an academic pursuit without clinical significance.
Conclusion:
The unresolved pro-con debate on peripheral nerve blockades in extremity trauma requires further understanding of ischemic transmission pathways, the impact of PNBs on those pathways, and developing more objective metabolic surveillance parameters to indicate the progression of ACS. Implementing new protocols in healthcare systems necessitates careful consideration due to the potential risks involved.
From Myron: What do you do in your practice? Do you completely avoid peripheral neural blockade? If you do use peripheral nerve blocks, do you use single shot or continuous infusions? Do you use standard concentrations of local anesthetics, or do you dilute them? If you use peripheral nerve blocks how are patients monitored? Please send your responses to me and I will post in Friday’s Reader Response.
References:
1. Samet RE, Torrie AM, Chembrovich SV, Ihnatsenka BV. Pro-Con Debate: Peripheral Nerve Blockade Should Be Provided Routinely in Extremity Trauma, Including in Patients At Risk for Acute Compartment Syndrome. Anesthesia and analgesia. May 1 2023;136(5):855-860. doi:10.1213/ane.0000000000006394
2. Sinatra R. Causes and consequences of inadequate management of acute pain. Pain medicine (Malden, Mass). Dec 2010;11(12):1859-71. doi:10.1111/j.1526-4637.2010.00983.x
3. Livingston K, Glotzbecker M, Miller PE, Hresko MT, Hedequist D, Shore BJ. Pediatric Nonfracture Acute Compartment Syndrome: A Review of 39 Cases. Journal of pediatric orthopedics. Oct-Nov 2016;36(7):685-90. doi:10.1097/bpo.0000000000000526
4. Walker BJ, Noonan KJ, Bosenberg AT. Evolving compartment syndrome not masked by a continuous peripheral nerve block: evidence-based case management. Regional anesthesia and pain medicine. Jul-Aug 2012;37(4):393-7. doi:10.1097/AAP.0b013e31824df1ac
5. Shore BJ, Glotzbecker MP, Zurakowski D, Gelbard E, Hedequist DJ, Matheney TH. Acute compartment syndrome in children and teenagers with tibial shaft fractures: incidence and multivariable risk factors. Journal of orthopaedic trauma. Nov 2013;27(11):616-21. doi:10.1097/BOT.0b013e31828f949c
6. Lin JS, Samora JB. Pediatric acute compartment syndrome: a systematic review and meta-analysis. J Pediatr Orthop B. Jan 2020;29(1):90-96. doi:10.1097/bpb.0000000000000593
7. Missair A, Visan A, Ivie R, Gebhard RE, Rivoli S, Woodworth G. Daring discourse: should acute pain medicine be a stand-alone service? Regional anesthesia and pain medicine. Jun 2021;46(6):529-531. doi:10.1136/rapm-2020-102288
8. Kucera TJ, Boezaart AP. Regional anesthesia does not consistently block ischemic pain: two further cases and a review of the literature. Pain medicine (Malden, Mass). Feb 2014;15(2):316-9. doi:10.1111/pme.12235
9. Wahal C, Grant SA, Gadsden J, Rambhia MT, Bullock WM. Femoral artery block (FAB) attenuates thigh tourniquet-induced hypertension: a prospective randomized, double-blind, placebo-controlled trial. Regional anesthesia and pain medicine. Mar 2021;46(3):228-232. doi:10.1136/rapm-2020-102113