Ultrasound-assisted Lumbar Punctures: A Systematic Review and Meta-Analysis

Ultrasound-guided paramedian approach: A novel technique for lumbar puncture in the Emergency Department

Lumbar puncture is performed to evaluate for multiple neurologic conditions, including meningitis and subarachnoid hemorrhage. However, success rates with the landmark-based technique are limited. Ultrasound is most commonly used for pre-marking without dynamic guidance, which presents several limitations, including absence of real-time guidance and lack of reliability if any patient movement occurs after skin marking. We describe a novel, ultrasound-guided paramedian approach which was successfully performed in the Emergency Department setting for lumbar puncture. Physicians should consider this technique as an alternate model using real-time guidance to reduce needle passes in those with difficult anatomy.

Lumbar Puncture

Lumbar puncture (LP) is a procedural skill that is required for practice in the emergency care setting, most often for diagnostic purposes. Rarely, it can also be used therapeutically, to alleviate the pain of patients presenting to the emergency department with acute headache from idiopathic intracranial hypertension. In either case, LP constitutes an invasive procedure in which the subarachnoid space is entered in order to obtain a sample of cerebrospinal fluid from one of the most vulnerable areas of the human anatomy. It is essential for the emergency clinician to carefully weigh the risks and benefits of LP, to ensure informed consent when possible, and to proceed in a manner that ensures optimal patient safety and effectiveness. This article reviews current recommendations and considerations around performing LP, in addition to the process for performing the procedure.

Ultrasound-Assisted Lumbar Punctures in Children: An Updated Systematic Review With Meta-Analysis

CONTEXT

Lumbar puncture (LP) is a common procedure in children, but the rates of unsuccessful and traumatic LPs remain high. Point-of-care ultrasound (POCUS) has been proposed as a tool for improvement.

OBJECTIVES

Our aim was to systematically review current evidence on the usefulness of POCUS assisted LP in children.

DATA SOURCES

PubMed, Embase, and the CENTRAL were searched up to November 2022.

STUDY SELECTION

We searched for randomized control trials assessing the effectiveness of POCUS assisted LP in children.

DATA EXTRACTION

Data were extracted by 2 reviewers independently.

RESULTS

Seven randomized control trials involving 618 participants were included. Overall, the first attempt POCUS assisted LP was successful in 72% compared with 59.6% in the standard group, regardless of the definition used. The calculated risk difference was 13.0% (95% confidence interval [CI]: 3% to 23%) I2:53%, odds ratio: 2.00 (95% CI: 1.13 to 3.53), I2: 45% and risk ratio:1.21 (95% CI: 1.01 to 1.44) I2:64%. Additionally, fewer traumatic LPs occurred in the US-assisted group, with a risk difference of -12% (95% CI: -0.22 to -0.03), odds ratio: 0.45 (95% CI: 0.26 to 0.78) and risk ratio: 0.53 (95% CI: 0.35 to 0.79). POCUS did not extend the duration of LP procedure with mean difference: -1.11 (95% CI: -2.88 to 0.66).

CONCLUSIONS

POCUS improved the first attempt success rate and reduced the incidence of traumatic LPs compared with standard LP procedure in children. Therefore, if it is available, POCUS should be used routinely before every LP, especially when performed by less experienced physicians.

Point-of-care ultrasound for airway management in the emergency and critical care setting

Airway management is a common procedure within emergency and critical care medicine. Traditional techniques for predicting and managing a difficult airway each have important limitations. As the field has evolved, point-of-care ultrasound has been increasingly utilized for this application. Several measures can be used to sonographically predict a difficult airway, including skin to epiglottis, hyomental distance, and tongue thickness. Ultrasound can also be used to confirm endotracheal tube intubation and assess endotracheal tube depth. Ultrasound is superior to the landmark-based approach for locating the cricothyroid membrane, particularly in patients with difficult anatomy. Finally, we provide an algorithm for using ultrasound to manage the crashing patient on mechanical ventilation. After reading this article, readers will have an enhanced understanding of the role of ultrasound in airway management.

Proportion of Successful Lumbar Punctures in Infants Younger Than Three Months

It is important to perform lumbar punctures (LPs) without a single traumatic tap in infants younger than three months owing to the risk of serious complications. The proportion of LPs in which clear cerebrospinal fluid (CSF) was obtained has been previously reported, but some of the procedures involved a traumatic tap. The present study aimed to identify the proportion of LPs in which clear CSF was obtained without a single traumatic tap and the factors associated with successful LPs in infants younger than three months. This retrospective, observational study included children younger than three months who underwent an LP in the pediatric emergency department between April 2018 and March 2021. The primary outcome was the proportion of successful LPs, defined as LPs obtaining clear CSF without a single traumatic tap. Multiple logistic regression analysis was used to identify factors related to successful LPs. Of 126 eligible patients, 121 were included. Among these, 83 (69%) were in the successful group. No factors significantly associated with successful LPs were found. Larger studies based on an accurate definition of successful LPs, such as that provided by this study, are needed to investigate related factors to increase the rate of successful LPs in this age group.

Point-of-Care Ultrasound-History, Current and Evolving Clinical Concepts in Emergency Medicine

Point-of-care ultrasound (PoCUS) has become an indispensable standard in emergency medicine. Emergency medicine ultrasound (EMUS) is the application of bedside PoCUS by the attending emergency physician to assist in the diagnosis and management of many time-sensitive health emergencies. In many ways, using PoCUS is not only the mere application of technology, but also a fusion of already existing examiner skills and technology in the context of a patient encounter. EMUS practice can be defined using distinct anatomy-based applications. The type of applications and their complexity usually depend on local needs and resources, and practice patterns can vary significantly among regions, countries, or even continents. A different approach suggests defining EMUS in categories such as resuscitative, diagnostic, procedural guidance, symptom- or sign-based, and therapeutic. Because EMUS is practiced in a constantly evolving emergency medical setting where no two patient encounters are identical, the concept of EMUS should also be practiced in a fluid, constantly adapting manner driven by the physician treating the patient. Many recent advances in ultrasound technology have received little or no attention from the EMUS community, and several important technical advances and research findings have not been translated into routine clinical practice. The authors believe that four main areas have great potential for the future growth and development of EMUS and are worth integrating: 1. In recent years, many articles have been published on novel ultrasound applications. Only a small percentage has found its way into routine use. We will discuss two important examples: trauma ultrasound that goes beyond e-FAST and EMUS lung ultrasound for suspected pulmonary embolism. 2. The more ultrasound equipment becomes financially affordable; the more ultrasound should be incorporated into the physical examination. This merging and possibly even replacement of aspects of the classical physical exam by technology will likely outperform the isolated use of stethoscope, percussion, and auscultation. 3. The knowledge of pathophysiological processes in acute illness and ultrasound findings should be merged in clinical practice. The translation of this knowledge into practical concepts will allow us to better manage many presentations, such as hypotension or the dyspnea of unclear etiology. 4. Technical innovations such as elastography; CEUS; highly sensitive color Doppler such as M-flow, vector flow, or other novel technology; artificial intelligence; cloud-based POCUS functions; and augmented reality devices such as smart glasses should become standard in emergencies over time.

Wearable Mechatronic Ultrasound-integrated AR Navigation System for Lumbar Puncture Guidance

As one of the most commonly performed spinal interventions in routine clinical practice, lumbar punctures are usually done with only hand palpation and trial-and-error. Failures can prolong procedure time and introduce complications such as cerebrospinal fluid leaks and headaches. Therefore, an effective needle insertion guidance method is desired. In this work, we present a complete lumbar puncture guidance system with the integration of (1) a wearable mechatronic ultrasound imaging device, (2) volume-reconstruction and bone surface estimation algorithms and (3) two alternative augmented reality user interfaces for needle guidance, including a HoloLens-based and a tablet-based solution. We conducted a quantitative evaluation of the end-to-end navigation accuracy, which shows that our system can achieve an overall needle navigation accuracy of 2.83 mm and 2.76 mm for the Tablet-based and the HoloLens-based solutions, respectively. In addition, we conducted a preliminary user study to qualitatively evaluate the effectiveness and ergonomics of our system on lumbar phantoms. The results show that users were able to successfully reach the target in an average of 1.12 and 1.14 needle insertion attempts for Tablet-based and HoloLens-based systems, respectively, exhibiting the potential to reduce the failure rates of lumbar puncture procedures with the proposed lumbar-puncture guidance.

Why, How Often, and What Happens When We Fail: A Retrospective Analysis of Failed Fluoroscopically Guided Lumbar Punctures

BACKGROUND AND PURPOSE

Important information regarding fluoroscopically guided lumbar puncture (FGLP) performance and referrals is lacking. The purpose of our study was to elucidate the success rate for initial FGLP attempts and re-attempts, reasons for unsuccessful FGLPs, and the relationship between clinical indications and whether patients will undergo a fluoroscopically guided re-attempt, among others.

MATERIALS AND METHODS

This retrospective study analyzed failed FGLP attempts in hospitalized adult patients at an academic hospital between June 2016 and March 2022. Unsuccessful FGLPs were labeled as insufficient CSF egress. FGLP reports and patients' clinical charts were analyzed for pertinent information such as clinical indication, reason for failure, whether patients received IV fluid before fluoroscopically guided spinal puncture attempt, and which patients returned for another FGLP attempt. Patients' ages and sex were analyzed using descriptive statistics. The OR was used to investigate the relationship between the clinical indications to perform FGLP and whether patients returned for a re-attempt.

RESULTS

Sixty-three of 1389 (4.5%) patients (median age, 62 years) had failed the initial FGLPs administered by 39 trainees. Twenty-eight of 63 (44.4%) patients (median age, 64 years) underwent a re-attempt within a median of 2 days after the first attempt, and 27/28 (96.4%) re-attempts were successful. A dry tap, no egress of CSF was the top reason (58.7%) for failed FGLP, and 12/13 of patients had a successful FGLP after IV hydration. Twenty-seven of 63 (43%) patients did not undergo a repeat attempt, and 100% were subsequently discharged from the hospital. There was no difference (P > .05) in the likelihood of patients returning for a repeat FGLP based on the clinical indications.

CONCLUSIONS

Initial and repeat FGLPs have very high success rates. No difference exists in the likelihood of patients returning for a re-attempt based on clinical indication.

Bioimpedance spinal needle provides high success and low complication rate in lumbar punctures of pediatric patients with acute lymphoblastic leukemia

In this prospective single-arm study of 50 pediatric patients with acute lymphoblastic leukemia (ALL), we evaluated the clinical performance of a novel bioimpedance spinal needle system in 152 intrathecal treatment lumbar punctures (LP) of these patients. The system detects in real-time when the needle tip reaches the cerebrospinal fluid (CSF) in the spinal canal. The success was defined as getting a CSF sample and/or administering the intrathecal treatment with one needle insertion. Incidence of traumatic LP (TLP) was defined as ≥ 10 erythrocytes/µL of CSF. Post-procedural complications were monitored with a one-week diary and one-month register follow-up. The success of the first attempt was 79.5%, with the CSF detection sensitivity of 86.1%. The incidence of TLP was 17.3%. A successful first attempt was associated with a significantly lower incidence of TLP (10% vs 40%, p = 0.0015). During the week after the procedure, the incidence of post-dural puncture headache was 6%. During the follow-up, no major complications were observed. In conclusion, the novel bioimpedance spinal needle system achieved a high success rate and low incidence of TLP and other complications in pediatric patients with ALL in a real-world clinical setting, indicating clinical utility for this system in pediatric hemato-oncology.

Point-of-Care Ultrasound in the Pediatric Intensive Care Unit

Ultrasonography has been widely used in medicine for decades but often by specific users such as cardiologists, obstetricians, and radiologists. In the last several years, the use of this imaging modality has moved to the bedside, with clinicians performing and interpreting focused point of care ultrasonography to aid in immediate assessment and management of their patients. The growth of point of care ultrasonography has been facilitated by advancement in ultrasound-related technology and emerging studies and protocols demonstrating its utility in clinical practice. However, considerable challenges remain before this modality can be adopted across the spectrum of disciplines, primarily as it relates to training, competency, and standardization of usage. This review outlines the history, current state, challenges and the future direction of point of care ultrasonography specifically in the field of pediatric critical care medicine.

Real-time ultrasound-guided lumbar puncture in the neonatal intensive care unit

OBJECTIVE

To determine the rates of traumatic lumbar puncture (LP) and overall success rates using the real-time ultrasound-guided technique when performed by a neonatal point-of-care ultrasound provider.

STUDY DESIGN

Retrospective observational study of 17 infants in the neonatal intensive care unit who underwent a real-time ultrasound-guided LP between March 2015 and November 2016. Spearman's correlation was calculated.

RESULTS

The first attempt and overall success rates were 65% and 100%, respectively. The rate of nontraumatic LP was 69%. CSF RBC count was inversely correlated with both PMA (Spearman's correlation coefficient (r_s) = -0.74, p = 0.0017) and weight (r_s = -0.74, p = 0.0015) at the time of LP.

CONCLUSIONS

This study is the first to provide evidence of high success rates with real-time ultrasound-guided LP when performed by a neonatologist. Our data demonstrate feasibility in neonates over a broad range of weights, including premature infants as small as 750 g.

Bedside Ultrasound for Procedural Assistance in Pediatrics

Point-of-care ultrasound (POCUS) is a noninvasive imaging tool with both diagnostic and therapeutic applications. In this article, the author will review the role of POCUS for vascular access, endotracheal intubation, lumbar puncture, chest tube, and diagnosing coronavirus disease 2019 lung pathology. This will include a review of the evidence, technique, and strategies for optimizing performance of these procedures. [Pediatr Ann. 2021;50(10):e404-e410.].

Retrospective analysis of predisposing factors for difficult lumbar punctures requiring image guidance in pediatric oncology patients

Success rates of lumbar punctures (LPs) in children are reportedly as low as 50%. In addition to procedural complications and failure, difficult LPs are a risk factor for traumatic LPs (TLPs), which can potentially affect diagnostic utility and alter treatment plans for pediatric oncology patients. To identify the intrinsic factors associated with technically difficult LPs in the pediatric oncology population, we performed a retrospective review of patients who required diagnostic imaging modalities for LP procedures at a single pediatric oncology institution between September 2008 and November 2018. We evaluated data from 64 LPs performed in 33 patients who were referred for image-guided LPs after undergoing technically difficult LPs that were unsuccessful using anatomic landmarks. In these cases, 96.9% of patients had at least one of the following intrinsic factors: body mass index (BMI) ≥ 25, anatomic spinal abnormalities, history of ≥ 5 previous LPs, age < 12 months, and history of back surgery. Elevated BMI was the most common factor associated with difficult LP (81.8%), followed by spinal abnormalities (51.5%), and history of ≥ 5 previous LPs (33.3%). Age < 12 months and history of back surgery were also associated with difficult LPs, but at a lower frequency. On the basis of these findings, we propose clinical recommendations for preprocedural identification of patients at risk of difficult LPs to reduce complications, including TLP, failure, and exposure to general anesthesia.

Milestone Approach to Designing a Point-of-Care Ultrasound Curriculum for Transition-to-Residency Programs in the United States

Phenomenon: Point-of-care ultrasound is fast becoming standard clinical bedside practice for diverse specialties. Medical schools are responding by adding ultrasound education, though the majority use it to supplement the learning of basic sciences. Point-of-care ultrasound practice-based clinical skills education is rare. There also is a lack of standardization across curricula, leading to much variability in the ultrasound skills that medical students from different schools bring to residency. To best inform a point-of-care ultrasound curriculum for our Transition-to Residency program, we investigated literature on 1) how medical students are being prepared for use of point-of-care ultrasound in clinical practice, 2) what skills are being taught, 3) what point-of-care ultrasound skills residency programs expect from incoming residents. Approach: We reviewed literature to identify curricula in U.S. medical schools that teach the concepts, knowledge, and skills related to point-of-care ultrasound. We also mapped point-of-care ultrasound expectations set forth by the Entrustable Professional Activities for undergraduate medical education to the specialty-specific milestones identified by the Accreditation Council for Graduate Medical Education. Additionally, we reviewed specialty-specific professional organizations for position statements and guidelines describing the point-of-care ultrasound skills expected for practicing physicians in their respective specialties. The goal was to identify any needs and gaps in education regarding point-of-care ultrasound across the undergraduate to graduate medical education continuum to practice. Findings: We found seven published point-of-care ultrasound curricula for medical students. There was wide variability in these curricula regarding what point-of-care ultrasound content is being taught, as well as when and how this skill is taught. No Entrustable Professional Activity listed point-of-care ultrasound as a skill requirement for graduating medical students. For graduate medical education, there was wide variability across specialties in residency milestones related to point-of-care ultrasound; some (e.g., emergency medicine) listed extensive milestones while others (e.g., internal medicine) listed none. However, we found that many specialty-specific professional organizations do list detailed point-of-care ultrasound expectations for their practicing physicians. Insights: As point-of-care ultrasound is fast becoming common practice across many specialties, standardization of education and related competencies-similar to other clinical skills training-is necessary across medical schools. Mapping point-of-care ultrasound expectations to current teaching across the continuum from undergraduate to graduate medical education may allow schools to tailor point-of-care ultrasound training for Transition-to-Residency programs. We provide a sample pilot point-of-care ultrasound curriculum that we designed for our Transition-to-Residency course.

Feel It, See It, Get It: Is Internal Medicine Residents' Use of Ultrasound in Lumbar Puncture Associated With Higher Success Rate?

INTRODUCTION

 Multiple emergency medicine and anesthesiology research studies suggest that ultrasound (US) is potentially useful in assisting with needle insertion in a lumbar puncture (LP). However, little is known about its value when utilized by internal medicine (IM) residents. The objective of this study is to examine whether the use of ultrasound in LPs performed by internal medicine residents is associated with a higher success rate than the traditional palpation method.

MATERIALS AND METHODS

 We reviewed all LP procedure notes in our hospital's records written by IM residents from June 2017 to December 2018 in a single community teaching hospital. We examined the association between the US use and success using the Chi-squared test and logistic regression model.

RESULTS

Among the 152 lumbar punctures documented, 130 specified whether US was used or not. Among these, 39 were ultrasound-assisted and 91 were not. Use of ultrasound was associated with a higher success rate compared to the non-ultrasound-use (87% vs 73%; p=0.1). The association was strengthened using logistic regression but did not reach statistical significance (OR 3.5; CI: 0.9 -13.8; p=0.07). Success was significantly associated with a fewer number of attempts (p<0.001). No statistically significant association was found between success and patients' body mass index (BMI; p=0.57), or level of training (p=0.11).

CONCLUSIONS

 Use of ultrasound for needle insertion in lumbar punctures performed by internal medicine residents was associated with a higher success rate compared to the palpation method but without statistical significance. Ultrasound is a non-invasive, quick, and safe tool. Our study favors its use as an aid during lumbar puncture when performed by internal medicine residents. Larger studies are needed to gather more evidence in support of this conclusion.

Ultrasound-assisted intrathecal injection of nusinersen in a patient with severe vertebral deformity: a case report

Background

Spinal muscular atrophy (SMA) is a mostly autosomal recessive genetic disease characterized by progressive muscle weakness from anterior horn degeneration. Nusinersen has recently been approved as a disease-modifying drug for SMA that needs to be administered intrathecally. Its injection is often associated with extreme difficulty since patients with SMA have severe vertebral deformity and may be with vertebral instrumentation.

Case description

A 21-year-old female with type 2 SMA and spinal deformity underwent a series of intrathecal injections of nusinersen. The intrathecal injections have been safely and successfully done by using computed tomography imaging and ultrasonography-assisted technique.

Conclusion

This the first report in which ultrasound-assisted technique has been used for the injection of nusinersen through a lumbar puncture in patients with severe spinal deformity. Use of preprocedural ultrasound imaging is highly recommended for treatments that repeatedly require intrathecal access.

Minimum local anesthetic dose of ropivacaine in real-time ultrasound-guided intraspinal anesthesia for lower extremity surgery: a randomized controlled trial

Background

Despite the many advantages real-time ultrasound-guided lumbar anesthesia has over traditional lumbar anesthesia, it seemingly involves a much higher dose of ropivacaine. This study aimed to determine the minimum local anesthetic dose (MLAD) and the 95% confidence interval of ropivacaine at different concentrations in real-time ultrasound-guided lumbar anesthesia for lower extremity surgery.

Methods

A total of 60 patients who were consecutively scheduled for selective lower extremity surgery were enrolled. The patients were randomly divided into two groups, which each received different concentrations of ropivacaine at different initial dosages when Dixon's up-and-down sequential method was applied. The high ropivacaine group and the low ropivacaine group received 0.75% and 0.5% ropivacaine, respectively. The patients' baseline characteristics, the MLAD, and the 95% confidence interval were assessed. The highest level of sensory block, time to reach the T10 sensory block, duration for sensory blocks higher than T10, highest plane for sensory block, and onset time and duration for motor block were recorded. Comparisons were also made between the patients' vital signs and adverse reactions.

Results

The minimum local anaesthetic dose (MLAD) and 95% confidence interval in the high ropivacaine group and the low ropivacaine group were 17.176 (16.276 to 18.124) and 20.192 (19.256 to 21.174) mg, respectively. Moreover, motor block maintenance was greatly reduced in the 0.5% ropivacaine compared to the 0.75% ropivacaine group (P=0.0309).

Conclusions

In real-time ultrasound-guided intraspinal anesthesia for lower extremity surgery, both 0.75% and 0.5% ropivacaine provide satisfactory anesthesia. Our results suggest that shortened motor block duration can hold benefits for patients including earlier mobilization and a quicker rehabilitation process.

Morphological parameters of fourth lumbar spinous process palpation: a three-dimensional reconstruction of computed tomography

Background

The localization of lumbar fourth spinous process (L4-SP) is an important anatomical landmark, and identifying its accurate position is essential for the diagnosis and treatment of waist diseases.

Methods

Five hundred participants were scanned with positive and lateral computed tomography (CT), which aimed to clarify anatomic characteristics of L4-SP. Anatomical parameters of the surface localization of L4-SP were measured and recorded through a three-dimensional (3D) reconstruction.

Results

Five hundred participants were classified into three types according to the position of BC with the iliac spine. There are just 266 that the line between the highest point of the iliac spine on both sides located on L4-SP (type I, 53.20%), 16 above L4-SP (type II, 3.20%), and 218 below L4-SP (type III, 43.60%). BC in type I (15.92 ± 1.30 mm) is longer than type III (15.56 ± 1.32 mm). While the angle combined with AB and BC is different in the three groups, the angle in type I (173.00 ± 4.83°) is larger than that in type II (164.69 ± 5.50°) and type III (159.45 ± 8.39°). Other measurements were not found any significant differences between above.

Conclusion

The traditional palpation for L4-SP is not absolutely exact. The accuracy rate is only 53.20%, and the errors may cause serious consequences.

The Variability of Preferred Infant Lumbar Puncture Insertion Site Between Novice and Experienced Physicians

BACKGROUND

We sought to determine if vertebral interspace selection for performance of infant lumbar puncture (LP) varies between less experienced trainees and more experienced pediatric emergency medicine (PEM) attending physicians.

METHODS

We performed an observational prospective study using a convenience sample of infants aged 0 to 12 months presenting to a single emergency department. Trainees with limited LP experience (defined as less than 10 infant LPs performed) marked their preferred LP insertion site with an invisible ultraviolet pen. PEM attending physicians subsequently marked their preferred LP insertion site with a visible pen. A trained sonographer then performed a bedside ultrasound to confirm interspace concordance or discordance. Our primary outcome was the proportion of concordant marked insertion sites.

RESULTS

Of the 110 patients enrolled, 102 (92.8%) completed study procedures. Trainee and PEM attending LP interspace markings were concordant in 27% of cases. Trainees marked a preferred interspace below the level of the attending in 55% of patients: 29 (28.4%) marked one spot inferior, 20 (19.6%) marked two spots inferior, and seven (6.9%) marked three spots inferior in relation to the attending.

CONCLUSIONS

There is variability of preferred LP insertion site based on provider experience. Trainees with limited LP experience tended to mark insertion spaces more caudal than those marked by the attending physicians in an area where the subarachnoid space is slightly smaller.

Point of care ultrasonography from the emergency department to the internal medicine ward: current trends and perspectives

The advent of portable devices in the early 80s has brought ultrasonography to the patient's bedside. Currently referred to as 'point of care ultrasonography' (POCUS), it has become an essential tool for clinicians. Initially developed in the emergency and critical care settings, POCUS has gained increasing importance in internal medicine wards in the last decade, with both its growing diagnostic accuracy and portability making POCUS an optimal instrument for everyday clinical assessment and procedures. There is large body of evidence to confirm POCUS' superiority when compared to clinical examination and standard X-ray imaging in a variety of clinical situations. On the contrary, only few indications, such as procedural guidance, have a proven additional benefit for patients. Since POCUS is highly user-dependent, pre- and post-graduate curricula are needed and the range of use should be clearly defined. This review focuses on trends and perspectives of POCUS in the management of diseases frequently encountered in emergency and internal medicine. In addition, questions are raised regarding the teaching and supervision of POCUS needing to be addressed in the near future.

Factors Associated with Lumbar Puncture Participation in Alzheimer's Disease Research

BACKGROUND

Cerebrospinal fluid (CSF) provides insight into the spectrum of Alzheimer's disease (AD) pathology. While lumbar punctures (LPs) for CSF collection are generally considered safe procedures, many participants remain hesitant to participate in research involving LPs.

OBJECTIVE

To explore factors associated with participant willingness to undergo a research LP at baseline and follow-up research study visit.

METHODS

We analyzed data from 700 participants with varying cognition (unimpaired, mild cognitive impairment, and dementia) in the Wisconsin Alzheimer's Disease Research Center. We evaluated the relationship of demographic variables (age, sex, race, ethnicity, and years of education) and clinical variables (waist-to-hip ratio, body mass index, AD parental history, cognitive diagnosis) on decision to undergo baseline LP1. We evaluated the relationship of prior LP1 experience (procedure success and adverse events) with the decision to undergo follow-up LP2. The strongest predictors were incorporated into regression models.

RESULTS

Over half of eligible participants opted into both baseline and follow-up LP. Participants who underwent LP1 had higher mean education than those who declined (p = 0.020). White participants were more likely to choose to undergo LP1 (p < 0.001); 33% of African American participants opted in compared to 65% of white participants. Controlling for age, education, and AD parental history, race was the only significant predictor for LP1 participation. Controlling for LP1 mild adverse events, successful LP1 predicted LP2 participation.

CONCLUSION

Race was the most important predictor of baseline LP participation, and successful prior LP was the most important predictor of follow-up LP participation.

Recommendations on the Use of Ultrasound Guidance for Adult Lumbar Puncture: A Position Statement of the Society of Hospital Medicine

When ultrasound equipment is available, along with providers who are appropriately trained to use it, we recommend that ultrasound guidance should be used for site selection of lumbar puncture to reduce the number of needle insertion attempts and needle redirections and increase the overall procedure success rates, especially in patients who are obese or have difficult-to-palpate landmarks. We recommend that ultrasound should be used to more accurately identify the lumbar spine level than physical examination in both obese and nonobese patients. We suggest using ultrasound for selecting and marking a needle insertion site just before performing lumbar puncture in either a lateral decubitus or sitting position. The patient should remain in the same position after marking the needle insertion site. We recommend that a low-frequency transducer, preferably a curvilinear array transducer, should be used to evaluate the lumbar spine and mark a needle insertion site. A high-frequency linear array transducer may be used in nonobese patients. We recommend that ultrasound should be used to map the lumbar spine, starting at the level of the sacrum and sliding the transducer cephalad, sequentially identifying the lumbar spine interspaces. We recommend that ultrasound should be used in a transverse plane to mark the midline of the lumbar spine and in a longitudinal plane to mark the interspinous spaces. The intersection of these two lines marks the needle insertion site. We recommend that ultrasound should be used during a preprocedural evaluation to measure the distance from the skin surface to the ligamentum flavum from a longitudinal paramedian view to estimate the needle insertion depth and ensure that a spinal needle of adequate length is used. We recommend that novices should undergo simulation-based training, where available, before attempting ultrasound-guided lumbar puncture on actual patients. We recommend that training in ultrasound-guided lumbar puncture should be adapted based on prior ultrasound experience, as learning curves will vary. We recommend that novice providers should be supervised when performing ultrasound-guided lumbar puncture before performing the procedure independently on patients.