BackgroundAutoregulatory dysfunction is an important contributor to brain injury in premature infants, particularly intraventricular hemorrhage (IVH). The autoregulatory system acts as a filter that dampens the systemic blood flow to follow a normal cerebral perfusion profile.MethodsSimultaneous arterial blood pressure and cerebral near infrared spectroscopy (NIRS) data were collected from infants born before 28 weeks estimated gestational age (EGA). The resulting data were preprocessed and then divided into non-overlapping 20-minute epochs. The transfer function estimate was calculated to determine dampening ability.Results62 infants were prospectively recruited with a mean EGA of 25.4 ± 1.3 weeks and birth weight of 832 ± 199g. 67% were male, 24/62 had IVH, 17/62 received dopamine, 47/62 had antenatal steroid exposure, and 22/62 received fentanyl.Advancing EGA and birth weight z-score predicted stronger dampening while African-American race and IVH of any grade predicted weaker dampening.ConclusionThis preliminary report suggests an impairment in dampening ability associated with immaturity, decreased birth weight z-score and African-American race. Decreased dampening is also associated with IVH, although these results cannot distinguish between decreased dampening as an antecedent or sequela of IVH. These observations should be studied in a larger sample.

Objectives Conventional neonatology practice is to place umbilical venous catheters (UVCs) in central position and to limit the use of low-lying catheters. Our objectives were to describe the practices and complications associated with UVCs and to evaluate the type of infusates used with either UVC position. Study Design A retrospective chart review was performed at four neonatal intensive care units to identify neonates who underwent UVC placement over a 2-year period. Infant demographics, UVC position, catheter days, fluid and medication characteristics, and specific complications were extracted. Results A total of 2,011 neonates who underwent UVC placement were identified during the 2-year period. Of these, 641 UVCs (31.9%) were identified in the low-lying position. Centrally positioned UVCs were associated with lower gestational age and were left in situ for a longer duration than low-lying UVCs. Infusions of hyperosmolar solutions and vasopressors were significantly higher in central UVCs, though they were used in a significant number of low-lying UVCs. Complications, while not statistically different, were three times higher in low-lying UVCs. Conclusion Despite conventional teaching, low-lying UVCs were used in nearly one-third of infants in this cohort. Parenteral nutrition, antibiotics, and vasopressors were infused through central and low-lying UVCs. There was no statistically significant difference in complication rates between UVC positions.

The underlying mechanism as to why some hypotensive preterm infants do not respond to inotropic medications remains unclear. For these infants, we hypothesize that impaired vasomotor function is a significant factor and is manifested through a decrease in low-frequency blood pressure variability across regulatory components of vascular tone. Infants born ≤28 wk estimated gestational age underwent prospective recording of mean arterial blood pressure for 72 h after birth. After error correction, root-mean-square spectral power was calculated for each valid 10-min data frame across each of four frequency bands (, 0.005-0.0095 Hz; , 0.0095-0.02 Hz;, 0.02-0.06 Hz; and , 0.06-0.16) corresponding to different components of vasomotion control. Forty infants (twenty-nine normotensive control and eleven inotrope-exposed) were included with a mean ± SD estimated gestational age of 25.2 ± 1.6 wk and birth weight 790 ± 211 g. 9.7/11.8 Million (82%) data points were error-free and used for analysis. Spectral power across all frequency bands increased with time, although the magnitude was 20% less in the inotrope-exposed infants. A statistically significant increase in spectral power in response to inotrope initiation was noted across all frequency bands. Infants with robust blood pressure response to inotropes had a greater increase compared with those who had limited or no blood pressure response. In this study, hypotensive infants who require inotropes have decreased low-frequency variability at baseline compared with normotensive infants, which increases after inotrope initiation. Low-frequency spectral power does not change for those with inotrope treatment failure, suggesting dysfunctional regulation of vascular tone as a potential mechanism of treatment failure. In this study, we examine patterns of low-frequency oscillations in blood pressure variability across regulatory components of vascular tone in normotensive and hypotensive infants exposed to inotropic medications. We found that hypotensive infants who require inotropes have decreased low-frequency variability at baseline, which increases after inotrope initiation. Low-frequency spectral power does not change for those with inotrope treatment failure, suggesting dysfunctional regulation of vascular tone as a potential mechanism of treatment failure.

Objective This study aimed to determine clinical care practices for infants at risk for posthemorrhagic hydrocephalus (PHH) across level IV neonatal intensive care units (NICUs). Study Design Cross-sectional survey that addressed center-specific surveillance, neurosurgical intervention, and follow-up practices within the Children's Hospitals Neonatal Consortium. Results We had a 59% (20/34 sites) response rate, with 10 sites having at least two participants. Respondents included neonatologists (53%) and neurosurgeons (35%). Most participants stated having a standard guideline for PHH (79%). Despite this, 42% of respondents perceive inconsistencies in management. Eight same-center pairs of neonatologists and neurosurgeons were used to determine response agreement. Half of these pairs disagreed on nearly all aspects of care. The greatest agreement pertained to a willingness to adopt a consensus-based protocol. Conclusion Practice variation in the management of infants at risk of PHH in level IV NICUs exists despite the perception that a common practice is available and used. Key Points

Objective Identify factors associated with responsiveness to dopamine therapy for hypotension and the relationship to brain injury in a cohort of preterm infants. Study Design The pharmacy database at St. Louis Children’s Hospital was retrospectively queried to identify infants who (a) were born < 28 weeks gestation between 2012–14, (b) received dopamine, and (c) had blood pressure measurements from an umbilical arterial catheter. A control group was constructed from contemporaneous infants who did not receive dopamine. Mean arterial blood pressure (MABP) at baseline, 1h and 3h after initiating dopamine were obtained for each dopamine-exposed infant. MABP measurements at matched time points were obtained in the control group. Results Sixty-nine dopamine-treated and forty-five control infants were included. Mean ΔMABP at 3h was 4.5±6.3 mm of Hg for treated infants versus 1±2.9 for the control. Median dopamine starting dose was 2.5 µg/kg/min. Dopamine-treated infants were less mature and lower birth weight while also more likely to be intubated at 72h, diagnosed with intraventricular hemorrhage (IVH), and to die. Failure to respond to dopamine was associated with greater likelihood of developing IVH (OR 5.8, 95% CI 1.1–42.3), while a strong response (ΔMABP >10 mmHg) was associated with a reduction in risk of IVH (OR 0.1, 95% CI 0.01–0.8). Conclusions Low-moderate dose dopamine administration results in modest blood pressure improvements. A lack of response to dopamine is associated with a greater risk of IVH while a strong response is associated with a decreased risk. Further research into underlying mechanisms and management strategies is needed.