Lauren Thorngate

Electrode Challenges in Amplitude-Integrated Electroencephalography (aEEG): Research Application of a Novel Noninvasive Measure of Brain Function in Preterm Infants

Continuous real-time brain function monitoring of preterm infants offers a novel way to evaluate neurological development in neonatal intensive care. Direct measurement of brain function is difficult and complicated by vulnerabilities of the preterm infant population. This study illustrates the feasibility of using noninvasive hydrogel electrodes with amplitude-integrated electroencephalography (aEEG) as a simplified brain monitor in preterm infants. This article presents a systematic exploration of factors influencing the accuracy of aEEG measurement, especially skin preparation procedures and skin condition after electrode placement. The authors conducted aEEG recordings on 16 medically stable preterm infants at 31—36 weeks postmenstrual age in the neonatal intensive care unit between feedings and caregiving for approximately 3 hr. The authors systematically performed several strategies to improve electrode placement procedures and reduce skin impedance, including (a) examination of possible influences of environmental electrical equipment, (b) comparison of different hydrogel electrode types, (c) modification of skin preparation procedures, and (d) assessment of impacts of different skin conditions. The authors achieved improvements in the impedance value, length of uninterrupted recording, and percentage of the recording duration with measured impedance <20 kΩ (recommended acceptable limit). There was no report of skin irritation during or after the recording. The aEEG measurement at the bedside using hydrogel electrodes is noninvasive and feasible for reliable brain monitoring in preterm infants. This study demonstrated the importance of establishing systematic methods to ensure the accuracy and feasibility of physiologic measurements for nurse researchers.

NICU procedures are getting sweeter: development of a sucrose protocol for neonatal procedural pain.

Neonates in the neonatal intensive care nursery experience multiple, painful, tissue-damaging procedures daily. Pain among neonates is often underestimated and untreated, producing untoward consequences. A literature review established strong evidence supporting the use of sucrose as an analgesic for minor procedural pain among neonates. A review of unit practices and nurses’ experiential evidence initiated the production of a standardized protocol in our unit at the University of Washington Medical Center NICU in Seattle. Nursing practices surrounding sucrose use differed widely in dose, timing, and patient application. We carefully evaluated evidence documenting the effectiveness as well as the safety of sucrose administration and wrote a protocol and practice standards for our primarily premature patient population. This article describes the development and execution of a standardized, nurse-implemented, sucrose protocol to reduce procedural pain.

Seasonal mapping of NICU temperature.

PURPOSETo create a thermal map of ambient air, radiant, and evaporative temperatures and humidity throughout the NICU nursery by season across a calendar year. SUBJECTSEach cubicle of the 32-bed NICU, distributed across 5 rooms, in a level III nursery was measured. METHODSTemperatures were recorded at a consistent time on one day during January, April, July, and October. MAIN OUTCOME MEASURESAn electronic monitor (QUESTemp° 34; Quest Technologies, Oconomowoc, Wisconsin) was used to measure dry bulb, wet bulb, and globe thermometer temperatures. RESULTSAnalysis of variance revealed statistically significant (P < .000) differences in season, room, and season by room interaction. Room ambient air temperatures differed by less than 2°F across season. Radiant temperature paralleled air temperature. Humidity, the predominant difference across season, produced evaporative temperatures considerably lower than room air temperature, and the gradient between mean nursery dry bulb temperature and wet bulb temperature was 9.3°F in summer and 16.8°F in winter. CONCLUSIONSThe thermal map revealed seasonal thermal differences, particularly in humidity level and evaporative temperature. Room temperature alone does not reflect the total thermal environment. Recommendations include periodic assessment of nurseries along with air, evaporative, and radiant temperatures as well as humidity to fully appreciate the impact of the thermal environment on infants.

Quantification of neonatal amplitude-integrated EEG patterns

BACKGROUND Amplitude-integrated EEG (aEEG) is increasingly used in research with premature infants; however, comprehensive interpretation is limited by the lack of simple approaches for reliably quantifying and summarizing the data. AIM Explore operational measures for quantifying continuity and discontinuity, measured by aEEG as components of infant brain function. STUDY DESIGN An exploratory naturalistic study of neonates while in the Neonatal Intensive Care Unit (NICU). One single channel aEEG recording per infant was obtained without disruption of nursing care practices. SUBJECTS 24 infants with mean postmenstrual age (PMA) of 33.11 weeks (SD 3.49), average age of 2.62 weeks (SD 1.35) and mean birth weights of 1.39 kg (SD 0.73). OUTCOME MEASURES Quantification of continuity and discontinuity included bandwidth and lower border of aEEG, calculated proportion of time with signal amplitude below 10 μV, and peak counts. Variance of bandwidth and lower border denoted cycling. RESULTS Group mean bandwidth was 52.98 μV (SD 27.62). Median peak count in 60 second epochs averaged 3.63 (SD 1.74), while median proportion < 10 μV was 22% (SD 0.20). The group mean of lower border within-subject aggregated medians was 6.20 μV (SD 2.13). Group mean lower border standard deviation was 3.96 μV. Proportion < 10 μV showed a strong negative correlation with the natural log of the lower border median (r = -0.906, p < .0001) after controlling for PMA. CONCLUSIONS This study introduces a novel quantification process by counting peaks and proportion of time < 10 μV. Expanded definitions and analytic techniques will serve to strengthen the application of existing scoring systems for use in naturalistic research settings and clinical practice.

Practical Issues of Physiologic Measurement for Clinical Research with Children. Part I: Measurement Accuracy and Precision

Column Editor: Lauren Clark Scientific Inquiry provides a forum to facilitate the ongoing process of questioning and evaluating practice, presents informed practice based on available data, and innovates new practices through research and experimental learning.

Practical issues of physiologic measurement for clinical research with children. Part I

Column Editor: Lauren Clark Scientific Inquiry provides a forum to facilitate the ongoing process of questioning and evaluating practice, presents informed practice based on available data, and innovates new practices through research and experimental learning.