The Anterior Branch of the Medial Femoral Cutaneous Nerve Innervates Cutaneous and Deep Surgical Incisions in Total Knee Arthroplasty.

Background/Objectives: The intermediate femoral cutaneous nerve (IFCN), the saphenous nerve, and the medial femoral cutaneous nerve (MFCN) innervate the skin of the anteromedial knee region. However, it is unknown whether the MFCN has a deeper innervation. This would be relevant for total knee arthroplasty (TKA) that intersects deeper anteromedial genicular tissue layers. Primary aim: to investigate deeper innervation of the anterior and posterior MFCN branches (MFCN-A and MFCN-P). Secondary aim: to investigate MFCN innervation of the skin covering the anteromedial knee area and medial parapatellar arthrotomy used for TKA. Methods: This study consists of (1) a dissection study and (2) unpublished data and post hoc analysis from a randomized controlled double-blinded volunteer trial (EudraCT number: 2020-004942-12). All volunteers received bilateral active IFCN blocks (nerve block round 1) and saphenous nerve blocks (nerve block round 2). In nerve block round 3, all volunteers were allocated to a selective MFCN-A block. Results: (1) The MFCN-A consistently innervated deeper structures in the anteromedial knee region in all dissected specimens. No deep innervation from the MFCN-P was observed. (2) Sixteen out of nineteen volunteers had an unanesthetized skin gap in the anteromedial knee area and eleven out of the nineteen volunteers had an unanesthetized gap on the skin covering the medial parapatellar arthrotomy before the active MFCN-A block. The anteromedial knee area and medial parapatellar arthrotomy was completely anesthetized after the MFCN-A block in 75% and 82% of cases, respectively. Conclusions: The MFCN-A shows consistent deep innervation in the anteromedial knee region and the area of MFCN-A innervation overlaps the skin area covering the medial parapatellar arthrotomy. Further trials are mandated to investigate whether an MFCN-A block translates into a clinical effect on postoperative pain after total knee arthroplasty or can be used for diagnosis and interventional pain management for chronic neuropathic pain due to damage to the MFCN-A during surgery.

Fluid management of emergency department patients with sepsis-A survey of fluid resuscitation practices.

BACKGROUND: Fluid administration and resuscitation of patients with sepsis admitted through emergency departments (ED) remains a challenge, and evidence is sparse especially in sepsis patients without shock. We aimed to investigate emergency medicine physicians' and nurses' perceptions, self-reported decision-making and daily behavior, and challenges in fluid administration of ED sepsis patients. METHODS: We developed and conducted a multicenter, web-based, cross-sectional survey focusing on fluid administration to ED patients with sepsis sent to all nurses and physicians from the five EDs in the Central Denmark Region. The survey consisted of three sections: (1) baseline information; (2) perceptions of fluid administration and daily practice; and (3) clinical scenarios about fluid administration. The survey was performed from February to June, 2021. RESULTS: In total, 138 of 246 physicians (56%) and 382 of 595 nurses (64%) responded to the survey. Of total, 94% of physicians and 97% of nurses regarded fluid as an important part of sepsis treatment. Of total, 80% of physicians and 61% of nurses faced challenges regarding fluid administration in the ED, and decisions were usually based on clinical judgment. The most common challenge was the lack of guidelines for fluid administration. Of total, 96% agreed that they would like to learn more about fluid administration, and 53% requested research in fluid administration of patients with sepsis. For a normotensive patient with sepsis, 46% of physicians and 44% of nurses administered 1000 ml fluid in the first hour. Of total, 95% of physicians and 89% of nurses preferred to administer ≥1000 ml within an hour if the patients' blood pressure was 95/60 at admission. There was marked variability in responses. Blood pressure was the most commonly used trigger for fluid administration. Respondents preferred to administer less fluid if the patient in the scenario had known renal impairment or heart failure. Normal saline was the preferred fluid. CONCLUSION: Fluid administration is regarded as an important but challenging aspect of sepsis management. Responses to scenarios revealed variability in fluid volumes. Blood pressure was the most used trigger. ED nurses and physicians request evidence-based guidelines to improve fluid administration.

Effect of prehospital transportation on 24-h fluid volume, a post hoc analysis of a multicenter, prospective, observational study on fluid volumes in patients with suspected infection.

Introduction: Infections, including sepsis, are leading causes of death and fluid administration is part of the treatment. The optimal fluid therapy remains controversial. If the patient is transported by Emergency Medical Services (EMS), fluids can be initiated during transportation, which may result in increased overall fluid administration and fluid overload, which may be harmful. The aim of the study was to investigate the effect of EMS transportation on 24-h fluid administration in patients with suspected infection. Methods: This is a post hoc study of a prospective, multicenter, observational study, conducted in three Danish Emergency Departments (EDs), 20 January-2 March 2020, aiming at describing fluid administration in patients with suspected infection. Patients were stratified into the groups: simple infection or sepsis, in accordance with SEPSIS-3-guidelines. The primary outcome of the current study was 24-h total fluid volume (oral and intravenous) stratified by transportation mode to the EDs. Main results: Total 24-h fluids were registered for 734 patients. Patients with simple infection or sepsis arriving by EMS (n = 388, 54%) received mean 3,774 ml (standard deviation [SD]: 1900) and non-EMS received 3,627 ml (SD: 1568); mean difference (MD) was 303 ml [95% CI: 32; 573] adjusted for age, site, and total SOFA-score. Patients brought in by EMS received more intravenous fluids (MD: 621 ml [95% CI: 378; 864]) and less oral fluids (MD: -474 ml [95% CI: -616; -333]) than non-EMS patients. Conclusion: Patients transported by EMS received more intravenous fluids and less oral fluids but overall, more fluid in total in the first 24-h than non-EMS after adjusting for age, site and SOFA-score.

Twenty-four-hour fluid administration in emergency department patients with suspected infection: A multicenter, prospective, observational study.

BACKGROUND: To describe 24-hour fluid administration in emergency department (ED) patients with suspected infection. METHODS: A prospective, multicenter, observational study conducted in three Danish hospitals, January 20 to March 2, 2020. We included consecutive adult ED patients with suspected infection (drawing of blood culture and/or intravenous antibiotic administration within 6 hours of admission). Oral and intravenous fluids were registered for 24 hours. PRIMARY OUTCOME: 24-hour total fluid volume. We used linear regression to investigate patient and disease characteristics' effect on 24-hour fluids and to estimate the proportion of the variance in fluid administration explained by potential predictors. RESULTS: 734 patients had 24-hour fluids available: 387 patients had simple infection, 339 sepsis, eight septic shock. Mean total 24-hour fluid volumes were 3656 mL (standard deviation [SD]:1675), 3762 mL (SD: 1839), and 6080 mL (SD: 3978) for the groups, respectively. Fluid volumes varied markedly. Increasing age (mean difference [MD]: 60-79 years: -470 mL [95% CI: -789, -150], +80 years; -974 mL [95% CI: -1307, -640]), do-not-resuscitate orders (MD: -466 mL [95% CI: -797, -135]), and preexisting atrial fibrillation (MD: -367 mL [95% CI: -661, -72) were associated with less fluid. Systolic blood pressure < 100 mmHg (MD: 1182 mL [95% CI: 820, 1543]), mean arterial pressure < 65 mmHg (MD: 1317 mL [95% CI: 770, 1864]), lactate ≥ 2 mmol/L (MD: 655 mL [95% CI: 306, 1005]), heart rate > 120 min (MD: 566 [95% CI: 169, 962]), low (MD: 1963 mL [95% CI: 813, 3112]) and high temperature (MD: 489 mL [95% CI: 234, 742]), SOFA score > 5 (MD: 1005 mL [95% CI: 501, 510]), and new-onset atrial fibrillation (MD: 498 mL [95% CI: 30, 965]) were associated with more fluid. Clinical variables explained 37% of fluid variation among patients. CONCLUSIONS: Patients with simple infection and sepsis received equal fluid volumes. Fluid volumes varied markedly, a variation that was partly explained by clinical characteristics.

Randomized trial of ultrasound-guided superior cluneal nerve block.

BACKGROUND AND OBJECTIVES: The superior cluneal nerves originate from the dorsal rami of primarily the upper lumbar spinal nerves. The nerves cross the iliac spine to innervate the skin and subcutaneous tissue over the gluteal region. The nerves extend as far as the greater trochanter and the area of innervation may overlap anterolaterally with the iliohypogastric and the lateral femoral cutaneous (LFC) nerves. A selective ultrasound-guided nerve block technique of the superior cluneal nerves does not exist. A reliable nerve block technique may have application in the management of postoperative pain after hip surgery as well as other clinical conditions, for example, chronic lower back pain. In the present study, the primary aim was to describe a novel ultrasound-guided superior cluneal nerve block technique and to map the area of cutaneous anesthesia and its coverage of the hip surgery incisions. METHODS: The study was carried out as two separate investigations. First, dissection of 12 cadaver sides was conducted in order to test a novel superior cluneal nerve block technique. Second, this nerve block technique was applied in a randomized trial of 20 healthy volunteers. Initially, the LFC, the subcostal and the iliohypogastric nerves were blocked bilaterally. A transversalis fascia plane (TFP) block technique was used to block the iliohypogastric nerve. Subsequently, randomized, blinded superior cluneal nerve blocks were conducted with active block on one side and placebo block contralaterally. RESULTS: Successful anesthesia after the superior cluneal nerve block was achieved in 18 of 20 active sides (90%). The area of anesthesia after all successful superior cluneal nerve blocks was adjacent and posterior to the area anesthetized by the combined TFP and subcostal nerve blocks. The addition of the superior cluneal nerve block significantly increased the anesthetic coverage of the various types of hip surgery incisions. CONCLUSION: The novel ultrasound-guided nerve block technique reliably anesthetizes the superior cluneal nerves. It anesthetizes the skin posterior to the area innervated by the iliohypogastric and subcostal nerves. It improves the anesthetic coverage of incisions used for hip surgery. Among potential indications, this new nerve block may improve postoperative analgesia after hip surgery and may be useful as a diagnostic block for various chronic pain conditions. Clinical trials are mandated. TRIAL REGISTRATION NUMBER: EudraCT, 2016-004541-82.

Do ultrasound-guided regional blocks signify a new paradigm in high-risk patients?

It has been suggested for many years that regional anaesthesia is advantageous in high-risk patients, either as the sole anaesthetic or in combination with general anaesthesia. Regional techniques are safe and even more so when guided by ultrasound. In the high-risk patient population, ultrasound-guided regional anaesthesia (UGRA) can help decrease risk of perioperative morbidity and improve short-term as well as long-term outcomes, particularly in the orthopaedic, vascular, oncologic and chronic pain patient populations. Nevertheless, complications do still occur and benefits of a specific regional nerve blockade need to be weighed against potential risks on an individual basis. The emergence of reasonably priced, easy-to-use ultrasound machines facilitates regional anaesthesia, and this kind of anaesthesia may become the standard of care in high-risk patients.

Infusion of hypertonic saline (7.5%) does not change neutrophil oxidative burst or expression of endothelial adhesion molecules after abdominal hysterectomy.

BACKGROUND: Previous studies found hypertonicity to affect neutrophils in intact laboratory animals and in human blood cell cultures. We investigated whether infusion of hypertonic saline in a clinical relevant dose before hysterectomy affected peripheral blood neutrophils and their response to surgery. METHODS: Fifteen women scheduled for open abdominal hysterectomy were randomized double-blindly to infusion of 4 mL/kg 7.5% NaCl, 4 mL/kg 0.9% NaCl, or 32 mL/kg 0.9% NaCl over 20 minutes. Blood was collected at baseline, after infusion, 1, 4, and 24 hours postoperatively for the determination of leukocyte and differential count, neutrophil membrane expression of endothelial adhesion molecules by flow cytometry, and O2- -generation by superoxide dismutase-inhibitable reduction of cytochrome C. RESULTS: Surgery induced well-known changes in the number and distribution of white blood cells, reduced the expression of adhesion molecules, and halved the superoxide production unrelated to the tonicity or volume of the infused fluids. CONCLUSION: Infusion of a clinically relevant dose of hypertonic saline has no detectable effect on the membrane expression of endothelial adhesion molecules or O2- -generation in circulating neutrophils after elective abdominal hysterectomy.