Prospective Investigation of a Novel Ultrasound‐assisted Lumbar Puncture Technique on Infants in the Pediatric Emergency Department

Abstract

Objective: The objective was to describe a novel ultrasound-assisted lumbar puncture (UALP) technique and to compare it to standard lumbar puncture (SLP) technique in infants.Methods: A prospective, randomized, controlled study in infants 60 days old and younger undergoing a lumbar puncture (LP) in a pediatric emergency department. Patients with a spinal anomaly or ventriculoperitoneal shunt were excluded. Eligible infants were randomized to UALP or SLP. A spinal sonogram was performed on all patients by an investigator not involved in performing the LP. Spinal landmarks and maximum safe depth were identified for the UALP providers. Providers in the SLP group were blinded to sonographic measurements. A successful LP was defined as the collection of cerebrospinal fluid (CSF) with a red blood cell count of less than 10,000 cells/mm 3 . Statistical analysis included chi-square, Mann-Whitney U-test, and number needed to treat (NNT).Results: Forty-three patients were enrolled, 21 in the UALP group and 22 in the SLP group. Prematurity, weight, length, provider experience, anesthesia use, stylet technique, and number of attempts were similar between groups. The median age in the UALP group was 38 days (interquartile range [IQR] = 33 days) versus 45 days (IQR = 19 days) in the SLP group (p = 0.02). CSF was obtained in all UALP subjects (100%) versus in 18 of 22 (82%) in the SLP group (p = 0.04); 20 (95%) UALP subjects versus 15 (68%) SLP subjects met our definition of success (p = 0.023). The odds ratio of successful LP using UALP technique was 9.33 (95% confidence interval [CI] = 1.034 to 84.026) and the NNT was 3.7 (95% CI = 2.02 to 24.18). Conclusion:The UALP technique increases the rate of a successful LP in infants compared to standard technique.

Preprocedural Ultrasound for Infant Lumbar Puncture: A Randomized Clinical Trial

“…We chose a primary outcome that was particularly patient‐oriented; however, collection of enough CSF for a culture (regardless of attempts or amount of RBCS) is certainly of clinical importance. In the two prior trials, preprocedural US resulted in 9 and 18% increases in obtaining CSF on any attempts compared with only 2% difference in our study . The smaller difference we noted in this and other outcomes likely stems from our higher baseline rates of LP success using the palpation method and the variation in experience of the sonologists and those performing the LPs.…”

“…Our results should help alleviate the concern that adding US to the overall LP procedure will increase the overall duration of the LP procedure. Prior studies have similarly noted that the US procedure took minimal extra time . Another potential concern to use of US was that this new technique would not be well accepted; however, we found the US to be well tolerated by patients, family members, and LP procedural clinicians.…”

“…they similarly marked the interspace with a cross and additionally indicated the measured ideal depth of insertion by marking the actual spinal needle with a sterile marking pen. These differences may have accounted for the differing results found in our study . Given the current body of literature and because the majority (77%) of procedural clinicians expressed that they would like to use US prior to their next infant LP, additional multicenter studies are warranted to establish clinical utility, appropriate protocols, and training.…”

“…In the only other randomized trial of infant LPs, preprocedural US led to a 3% decrease in LP success when success was defined as CSF on first attempt with < 1,000 RBC per HPF (Michael Gorn, personal communication, December 6, 2016). However, in that study, the investigator's predefined primary outcome was CSF with < 10,000 RBC on any attempt, with US use associated with an improvement in LP success of 27% and only three sonologists trained in the protocol …”

“…Two prior randomized trials showed promising results for US assistance compared to standard techniques for interspace selection. However, these studies were single‐centered and used few sonologists and could therefore benefit from further studies to confirm their reproducibility and generalizability …”