Clinicians are often unable to successfully do a spinal tap. Ultrasound has been proposed as a method to improve success but it is not known if it helps. This study is designed to see if ultrasound improves the success rate.

Obtaining cerebrospinal fluid (CSF) through a lumbar puncture (LP) is an essential procedure in the neonatal/infant intensive care unit (N/IICU) for establishing diagnosis and determining treatment. The traditional technique for performing an LP involves palpation of anatomic landmarks followed by a "blind" stick of the appropriate inter-spinous process space. This technique has a failure rate (defined as the inability to obtain cerebrospinal fluid or obtaining a traumatic puncture) of 15-50%.

Bedside ultrasonography possesses the ability to visualize the anatomic landmarks, including the subarachnoid space. In the adult literature, ultrasound has been shown to reduce the LP failure rate. Its utility has also been shown to significantly improve success rates and accuracy in epidural needle placement in neonates and children undergoing regional anesthesia. Increasing the proportion of successful LPs in the N/IICU could significantly reduce patient/family discomfort, sedation exposure, off unit travel, additional interventional procedures and antibiotic use. However, research on the utility of bedside ultrasound assisted LPs by clinicians working in an N/IICU is lacking.

This is a prospective randomized controlled trial. Eligible subjects will be randomized to undergo LP (performed as part of their standard of care) with ultrasound assisted method or traditional landmark method.

Primary Objective:

-To determine if bedside ultrasound-assisted LP, performed by N/IICU clinicians on neonates and infants aged ≤6 months, increases the proportion of successful first attempt non-traumatic LPs when compared to a traditional landmark palpation technique.

Secondary Objectives:

• To determine if bedside-ultrasound assisted LPs increases the proportion of overall successful non-traumatic LPs within 2 attempts.
• To determine if bedside-ultrasound assisted LPs is associated with a decrease in the length of antibiotic exposure in patients undergoing LPs.

Inclusion Criteria:

1. Neonates and infants aged ≤6 months
2. Clinical indication for a lumbar puncture (LP), as determined by the clinical team
3. Availability of study personnel to perform bedside ultrasound

Exclusion Criteria:

1. Known spinal cord abnormality (for e.g., tethered cord, spina bifida)
2. Presence of skin and soft tissue infection at insertion site
3. Recent failed LP traumatic LP attempts within the preceding 48 hours
4. Recent diagnosis of intraventricular hemorrhage, within the preceding 7 days
5. Clinically unstable patient, as determined by the clinical team
6. Eligible patients on the resident care team