Recommendations on the Use of Ultrasound Guidance for Adult Lumbar Puncture: A Position Statement of the Society of Hospital Medicine
1) 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.
2) We recommend that ultrasound should be used to more accurately identify the lumbar spine level than physical examination in both obese and nonobese patients.
3) 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.
4) 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.
5) 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.
6) 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.
7) 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.
8) We recommend that novices should undergo simulation-based training, where available, before attempting ultrasound-guided lumbar puncture on actual patients.
9) We recommend that training in ultrasound-guided lumbar puncture should be adapted based on prior ultrasound experience, as learning curves will vary.
10) We recommend that novice providers should be supervised when performing ultrasound-guided lumbar puncture before performing the procedure independently on patients.
© 2019 Society of Hospital Medicine
Training
8) We recommend that novices should undergo simulation-based training, where available, before attempting ultrasound-guided LPs on actual patients.
Rationale. Similar to training for other bedside procedures, dedicated training sessions, including didactics, supervised practice on patients, and simulation-based practice, should be considered when teaching novices to perform ultrasound-guided LP. Simulation-based training facilitates acquisition of knowledge and skills to perform invasive bedside procedures, including LP.73 Simulation-based training has been commonly incorporated into procedure training for trainees using an immersive experience, such as a “boot camp,”74-77 or a standardized curriculum,78,79 and has demonstrated improvements in post-course procedural knowledge, technical skills, and operator confidence. Two of these studies included training in the use of ultrasound guidance for LP. These studies showed that simulation-based practice improved skill acquisition and confidence.80,81 Simulation using novel computer software may improve skill acquisition in the use of ultrasound guidance for LP.82
9) We recommend that training in ultrasound-guided LPs should be adapted based on prior ultrasound experience, as learning curves will vary.Rationale. The learning curve to achieve competency in the use of ultrasound guidance for LP has not been well studied. The rate of attaining competency in identifying lumbar spine structures using ultrasound will vary by provider based on prior skills in ultrasound-guided procedures.83 Thus, providers with prior ultrasound experience may require less training than those without such experience to achieve competency. However, extensive experience in performing landmark-guided LPs does not necessarily translate into rapid acquisition of skills to perform the procedure with ultrasound guidance. A study of practicing anesthesiologists with no prior ultrasound experience demonstrated that 20 supervised trials of ultrasound-guided spinal anesthesia were insufficient to achieve competency.84 Although minimums may be a necessary step to gain competence, using them as a sole means to define competence does not account for variable learning curves.12 Based on a national survey of 21 hospitalist procedure experts, the mean current vs suggested minimums for initial and ongoing hospital privileging for LPs were 1.8 vs 6.9 and 2.2 vs 4.6 annually in one report.85
A fundamental question that needs to be answered is how to define competency in the use of ultrasound guidance for LP, including the specific skills and knowledge that must be mastered. At a minimum, providers must be able to identify lumbar spinous processes and distinguish them from the sacrum, identify the lumbar interspinous spaces and their corresponding levels, and estimate the depth from the skin to the ligamentum flavum from the midline and paramedian planes. Novice operators may benefit from practicing lumbar spine mapping of nonobese patients using a high-frequency linear transducer that generates high-resolution images and facilitates recognition of lumbar spine structures.
10) We recommend that novice providers should be supervised when performing ultrasound-guided LPs before performing the procedure independently on patients.
Rationale: Demonstration of competency in the use of ultrasound to identify lumbar spine anatomy should be achieved before routinely performing the procedure independently on patients.18 All providers will require a variable period of supervised practice to demonstrate the appropriate technique, followed by a period of unsupervised practice before competency is achieved. Supervised practice with guidance and feedback has been shown to significantly improve providers’ ability to delineate lumbar spine anatomy.86
