Data indicate that nearly 400,000 lumbar punctures (LPs) are performed annually for either diagnostic workup or therapeutic relief in the United States. Regular referral to radiology for assistance in imaging guidance to aid with needle insertion can create unnecessary delays in care, which can be associated with delayed diagnosis and increased mortality. To reduce delays in performance of LPs, ultrasound (US) guidance can be used to mark a needle insertion site at the bedside. Evidence indicates that US guidance can reduce the number of needle insertion attempts and redirections and increase the overall LP success rate, explains Nilam J Soni, MD, MSc.
In recent years, many internal medicine physicians have gravitated away from performing invasive procedures at the bedside, says Dr. Soni. However, the risks associated with such procedures can be decreased with the assistance of point-of-care ultrasound (POCUS). “In 2014, Society of Hospital Medicine (SHM) members expressed the need for best practices and guidelines on use of POCUS by hospitalists, primarily for procedures,” says Dr. Soni. To develop a list of best practices on the use of POCUS for procedures, Dr. Soni assembled the SHM POCUS Task Force. The group of experts reviewed the literature on POCUS for performance of common bedside procedures, including LP, and drafted recommendations. The final list of consensus-based recommendations for LP was published in the Journal of Hospital Medicine, along with five additional position statements that are available on the journal’s website.
Recommendations are categorized into clinical outcomes, techniques, training, and knowledge gaps. Each draft recommendation includes a rationale and references cited from selected articles. The 27 members of the SHM POCUS Task Force voted to determine the final strength of the recommendations (Table). “Overall, the use of ultrasound guidance for LP reduces the number of attempts (needle insertions and redirections) and improves the overall procedural success rate of LP, with the greatest benefits in obese patients or those with otherwise difficult-to-palpate landmarks,” Dr. Soni says.
POCUS in Practice
“Use of POCUS to guide other common bedside procedures, like central line placement, thoracentesis, and paracentesis, is driven by the literature that has shown a reduction in procedural complications,” notes Dr. Soni. “However, for LP, there is less of a patient safety argument because a reduction in complications from use of US has not been definitively shown. A few factors drive POCUS use for LP that are not well captured by the literature. First, use of US allows operators to assess width of the interspinous spaces prior to attempting the procedure, and the operator can either choose the widest interspinous space to attempt the LP or refer the patient to a consultant to perform the procedure. Further, by visualizing the anticipated needle trajectory, POCUS gives operators a sense of how easy or difficult an LP will be. It also provides the ability to know how long of a needle is needed to perform the LP, especially in obese patients. Finally, when fewer needle insertions and redirections are needed to perform the procedure successfully, the experience of both the patient and provider is improved.”
Dr. Soni notes that he marks all of his patients with US prior to performing an LP, as it is generally more efficient than palpating the patient first or attempting the procedure blindly. “However, many physicians may choose to use US only when the landmarks are difficult to palpate,” he adds. “If the latter option is selected, it is important for physicians to obtain sufficient experience in marking the lumbar spine to achieve proficiency in the technique.”
Nilam J Soni, MD, MSc, Professor of Medicine, Director, Point-of-Care Ultrasound Training, VHA SimLEARN, Co-director, Medical School Ultrasound Curriculum, Director, Critical Care Ultrasound Education, South Texas Veterans Health Care System, University of Texas Health, San Antonio