A pilot study to examine maturation of body temperature control in preterm infants

Case Comparison of Preterm Infant Stability During Packed Red Blood Cell Transfusions

BACKGROUND

Very preterm infants (less than 32 weeks gestational age) experience acute morbidity during their stay in a neonatal intensive care unit. Because of their prematurity and frequent laboratory testing, they experience anemia, requiring correction with packed red blood cell (PRBC) transfusion(s). PRBC transfusions have been linked to neonatal morbidity, such as necrotizing enterocolitis, but never signs and symptoms of physiological stability.

OBJECTIVE

The secondary data analysis aimed to examine very preterm infants' physiological stability before, during, and after PRBC transfusions.

METHODS

A within-case, mixed-methods design was used in a secondary data analysis for 16 transfusion cases from 13 very preterm infants.

RESULTS

The findings showed very preterm infants with physiological variables falling within defined limits based on gestational age during the transfusion. Two contrasting case exemplars will be presented.

DISCUSSION

PRBC transfusions are necessary and prevent morbidity in very preterm infants. Observing instability during transfusions and prospectively studying hypothermia, cardiac instability, and thermal gradients is essential to design interventions to decrease morbidity associated with PRBC transfusions.

Synthetic MR Imaging-Based WM Signal Suppression Identifies Neonatal Brainstem Pathways in Vivo

BACKGROUND AND PURPOSE

Multidynamic multiecho sequence-based imaging enables investigators to reconstruct multiple MR imaging contrasts on the basis of a single scan. This study investigated the feasibility of synthetic MRI-based WM signal suppression (syWMSS), a synthetic inversion recovery approach in which a short TI suppresses myelin-related signals, for the identification of early myelinating brainstem pathways.

MATERIALS AND METHODS

Thirty-one cases of neonatal MR imaging, which included multidynamic multiecho data and conventionally acquired T1- and T2-weighted sequences, were analyzed. The multidynamic multiecho postprocessing software SyMRI was used to generate syWMSS data (TR/TE/TI = 3000/5/410 ms). Two raters discriminated early myelinating brainstem pathways (decussation of the superior cerebellar peduncle, medial lemniscus, central tegmental tract, and medial longitudinal fascicle [the latter 3 assessed at the level of the pons]) on syWMSS data and reference standard contrasts.

RESULTS

On the basis of syWMSS data, the decussation of the superior cerebellar peduncle (31/31); left/right medial lemniscus (31/31; 30/31); left/right central tegmental tract (19/31; 20/31); and left/right medial longitudinal fascicle (30/31) were reliably identified by both raters. On the basis of T1-weighted contrasts, the decussation of the superior cerebellar peduncle (14/31); left/right medial lemniscus (22/31; 16/31); left/right central tegmental tract (1/31); and left/right medial longitudinal fascicle (9/31; 8/31) were reliably identified by both raters. On the basis of T2-weighted contrasts, the decussation of the superior cerebellar peduncle (28/31); left/right medial lemniscus (16/31; 12/31); left/right central tegmental tract (23/31; 18/31); and left/right medial longitudinal fascicle (15/31; 14/31) were reliably identified by both raters.

CONCLUSIONS

syWMSS data provide a feasible imaging technique with which to study early myelinating brainstem pathways. MR imaging approaches that use myelin signal suppression contribute to a more sensitive assessment of myelination patterns at early stages of cerebral development.

Examining Use of Dual Point Temperature Display in Servo-Control With Early Preterm Infants

BACKGROUND

Previously, we recorded periods of time with foot higher than abdominal temperatures in association with infection in preterm infants. Monitoring dual temperatures may be an important tool to assess infant instability. Currently, incubators cannot measure and display dual temperatures in servo-control mode.

PURPOSE

To examine the usability of GE Healthcare's Giraffe OmniBed with research software to measure, display, and record dual temperatures, and their differences while in servo-control. In addition, nurses' perceptions of the use and display of dual temperatures and differences were evaluated.

METHODS

A multiple-case, mixed-methods design. Abdominal and foot temperatures were measured, displayed, and stored for 28 days for 14 preterm infants. Nurses were surveyed for satisfaction and preferences with the dual temperature display. Nurses noted abnormal temperature differences and infant condition in bedside journals.

RESULTS

Study infants were 26 to 31 weeks of gestational age and 670 to 1410 g. Abdominal, foot, and the abdominal-foot temperature difference was measured, recorded, and downloaded successfully in all infants over all days. Nurses liked using dual temperature display with the abdominal-foot temperature difference. Surveys indicated preferences for larger displays and alarms for abnormal values. Thermal instability, stimulation, and thermistor detachment were associated with abnormal thermal gradients. Two exemplar cases are presented.

IMPLICATIONS FOR PRACTICE

Monitoring dual temperatures adds information to the clinical assessment.

IMPLICATIONS FOR RESEARCH

Studies are needed to examine relationships between abnormal thermal gradients and infections, infant stability, and nursing care along with the underlying physiologic mechanisms. Studies are needed for wireless dual temperature monitoring.

Predicting Infection in Very Preterm Infants: A Study Protocol

BACKGROUND

Neonatal sepsis causes morbidity and mortality in preterm infants. Clinicians need a predictive tool for the onset of neonatal infection to expedite treatment and prevent morbidity. Abnormal thermal gradients, a central-peripheral temperature difference (CPtd) of >2°C or <0°C, and elevated heart rate characteristic (HRC) scores are associated with infection.

OBJECTIVE

This article presents the protocol for the Predictive Analysis Using Temperature and Heart Rate Study.

METHODS

This observational trial will enroll 440 very preterm infants to measure abdominal temperature and foot temperature every minute and HRC scores hourly for 28 days to compare infection data. Time with abnormal thermal gradients (Model 1) and elevated HRC scores (Model 2) will be compared to the onset of infections. For data analysis, CPtd (abdominal temperature - foot temperature) will be investigated as two derived variables, high CPtd (number/percentage of minutes with CPtd of >2°C) and low CPtd (number/percentage of minutes with CPtd of <0°C). In the infant-level model, the outcome yi will be an indicator of whether the infant was diagnosed with an infection in the first 28 days of life, and the high CPtd and low CPtd variables will be the average over the entire observation period, logit(yi) = β0 + xiβ1 + ziγ. For the day-level model, the outcome yit will be an indicator of whether the ith infant was diagnosed with an infection on the tth day from t = 4 through t = 28 or the day that infection is diagnosed (25 possible repeated measures), logit(yit) = β0 + xitβ1 + zitγ. It will be determined whether a model with only high CPtd or only low CPtd is superior in predicting infection. Also, the correlation of abnormal HRC scores with high CPtd and low CPtd values will be assessed.

DISCUSSION

Study results will inform the design of an interventional study using temperatures and/or heart rate as a predictive tool to alert clinicians of cardiac and autonomic instability present with infection.

Accuracy of the defining characteristics of the nursing diagnosis: Ineffective thermoregulation in newborns

OBJECTIVE

To identify the measures of accuracy for defining characteristics of the nursing diagnosis: Ineffective thermoregulation in newborns.

METHOD

Diagnostic accuracy study with cross-sectional design performed in medium and high-risk maternity units, located in Fortaleza city/Brazil. A total of 216 newborns were evaluated to identify the defining characteristics of the diagnosis under study. The measures of accuracy for defining characteristics were obtained from a latent class model with random effects for the calculation of sensitivity and specificity values.

RESULTS

The characteristics of increased respiratory rate and warm skin to the touch had higher sensitivity values (99.9%) and lower specificity (79 and 75%) and the characteristics of body temperature fluctuations above and below the normal parameters and hypertension had the highest specificity (80.4 and 100%, respectively).

CONCLUSION

The characteristic fluctuation of the body temperature above and below the normal parameters may be better to confirm the diagnosis, having presented a higher specificity value.

Thermal imaging applications in neonatal care: a scoping review

Background

In neonatal care, assessment of the temperature of the neonate is essential to confirm on-going health, and as an early signal of potential pathology. However, some methods of temperature assessment involve disturbing the baby, disrupting essential sleep patterns, and interrupting maternal/infant interaction. Thermal imaging is a completely non-invasive and non-contact method of assessing emitted temperature, but it is not a standard method for neonatal thermal monitoring. To examine the potential utility of using thermal imaging in neonatal care, we conducted a comprehensive systematic scoping review of thermal imaging applications in this context.

Methods

We searched EMBASE, MEDLINE and MIDIRS.

Results

From 442 hits, 21 met the inclusion criteria and were included in the review. A significant number (n = 9) were published in the last 8 years. All the studies were observational studies, with 20 out of 21 undertaken in North America or Europe. Most of them had small cohorts (range 4–29 participants). The findings were analysed narratively, to establish the issues identified in the included studies. Five broad themes emerged for future examination. These were: general thermal physiology; heat loss and respiratory monitoring; identification of internal pathologies, including necrotising enterocolitis; other uses of thermal imaging; and technical concerns. The findings suggest that thermal imaging is a reliable and non-invasive method for continuous monitoring of the emitted temperature of the neonates, with potential for contributing to the assurance of wellbeing, and to the diagnosis of pathologies, including internal abnormalities. However, the introduction of thermal imaging into everyday neonatology practice has several methodological challenges, including environmental parameters, especially when infants are placed in incubators or open radiant warmers.

Conclusion

In conclusion, although the first attempt at using thermal imaging in neonatal care started in the early-1970s, with promising results, and subsequent small cohort studies have recently reinforced this potential, there have not been any large prospective studies in this area that examine both the benefits and the barriers to its use in practice.

Surface Body Temperature of Full-Term Healthy Newborns Immediately after Birth-Pilot Study

The aim of the study was to perform an evaluation of chosen body surface temperatures in neonates immediately after birth, and to seek a relationship between those temperatures and the factors related both to the mother and newborn. The study included 74 healthy newborns. Maternal age, body weight, body mass index before pregnancy and on delivery day, birth and pregnancy order, newborn sex, birth weight, body length, pregnancy week on delivery, as well as newborn gasometric test results were collected. The highest temperature values were observed in the chest of the newborn. Significant relationships between the temperature of the evaluated areas were found. The parameters that correlated positively with the temperature of the back region were maternal body weight (both before pregnancy and on delivery day) as well as weight gain during pregnancy. The core and surface temperatures of the body are one of the most important elements of neonatal homeostasis and any changes constitute a risk to the newborn's health. It seemed that according to the surface temperature, the most important area that must be evaluated is the neonate's back, as it is most affected by appropriate weight gain during pregnancy.

Electronic Health Record Documentation of Nursing Care Procedures and Change in Weight of Healthy, Moderately Premature Neonates

PURPOSE

To identify the nursing care procedures (NCPs) performed in a NICU that disrupt the thermal environment by opening the incubator of moderately preterm neonates (mPNs) (32-34 wk gestational age) and the relationship between the frequency of these disruptions and change in weight (Δwt).

DESIGN

Survey and descriptive correlational methodology.

SAMPLE

Systematically identified, published references to NCPs that opening the incubator developed an itemized list of NCPs that was used to query the electronic health records (EHRs) of 164 mPNs in the first ten days of life (DOL).

MAIN OUTCOME VARIABLE

The Δwt between birth and ten DOL.

RESULTS

Of 51 NCPs identified, 26 were represented in the EHR. A mean of 614 (range 402-1,080; SD = 137) EHR-documented NCPs that opening the incubator were recorded. The frequency of NCPs was negatively correlated with the Δwt of mPNs at ten DOL, rs (164) = -.162, p = .038.

Negative Temperature Differential in Preterm Infants Less Than 29 Weeks Gestational Age: Associations With Infection and Maternal Smoking

BACKGROUND

Hypothermia is related to increased morbidity and mortality in very preterm infants; continuous temperature monitoring is necessary. Thermoregulation is limited in preterm infants.

OBJECTIVES

The purpose of the research was to assess and describe negative temperature differential (NTD) and assess the associations of NTD with infant demographic characteristics, medical history, and clinical events.

METHODS

An exploratory, case study design was used. Abdominal and foot temperature was measured every minute over the first 2 weeks of life in 22 preterm infants at less than 29 weeks gestational age.

RESULTS

All infants experienced NTD. Daily NTD in all infants across all study days ranged from 0 to 70.7%; 2-week mean NTD over all infants ranged from 7.3% to 38.5%. Four infants treated for late onset of infection had a higher NTD than 18 infants without infection (M = 27.8%, SD = 9.52 vs. M = 16.4%, SD = 5.34, p < .05). Although not statistically significant, higher mean percentage of NTD was noted in infants having early onset infection (24.1% vs. 16.4%), African American race (20.0% vs. 15.3%), and/or being born to a mother who smoked during pregnancy (26.6% vs. 16.7%).

DISCUSSION

A larger study is needed to examine associations between NTD and race, maternal smoking history, and infection. NTD might be used as a biomarker to guide acute clinical care and identify infants at risk for acute and chronic morbidity.

Body temperature in premature infants during the first week of life: Exploration using infrared thermal imaging

BACKGROUND

Hypothermia is a problem for very premature infants after birth and leads to increased morbidity and mortality. Previously we found very premature infants exhibit abnormal thermal patterns, keeping foot temperatures warmer than abdominal temperatures for their first 12h of life.

PURPOSE

We explored the utility of infrared thermography as a non-invasive method for measuring body temperature in premature infants in an attempt to regionally examine differential temperatures.

RESULTS

Our use of infrared imaging to measure abdominal and foot temperature for extremely premature infants in heated, humid incubators was successful and in close agreement using Bland and Altman technique with temperatures measured by skin thermistors.

CONCLUSIONS

Our study methods demonstrated that it was feasible to capture full body temperatures of extremely premature infants while they were resting in a heated, humid incubator using a Flir SC640 infrared camera. This technology offers researchers and clinicians a method to examine acute changes in perfusion differentials in premature infants which may lead to morbidity.

Perfusion Index in Very Low Birth Weight Premature Infants During Their First 2 Weeks of Life

BACKGROUND

Our program of research focuses on thermal and circulatory stability in extremely premature infants. In prior studies, we found that infants have long periods of time in which foot temperature (FT) is higher than central temperature. We thus wanted to determine whether blood flow in the foot is increased when FT is elevated. Perfusion index (PI) can be used as a clinical indicator of peripheral perfusion, but reports on use of PI in premature infants are lacking. We employed exploratory methodology to examine foot perfusion and temperature in very low birth weight infants.

AIMS

For premature infants after birth: (1) describe foot PI values for the first 2 weeks of life and (2) describe the relationship of longitudinal FT and PI.

STUDY DESIGN

Case study design with longitudinal FT and PI in 17 infants born at <29 weeks' gestation with birth weight < 1,200 g for 2 weeks after birth.

RESULTS

Infants averaged 851 g at birth and were 24-29 weeks' gestational age. The mean PI across all infants for 14 days was 1.04, SD = 0.79. Using a repeated measures multilevel model approach confirmed that FT and PI were positively related in these infants.

CONCLUSIONS

These findings demonstrate that perfusion is increased in the periphery in extremely premature infants when FT is increased. PI measures can be used as a trend for peripheral perfusion, and these values increase over the first 2 weeks of life in infants weighing more than 750 g.

Changes in physiological and behavioral parameters of preterm infants undergoing body hygiene: a systematic review

Objective To verify the effect of bathing on the body temperature of preterm infants (PTI). Method Systematic review conducted in the following bibliographic electronic sources: Biblioteca Virtual em Saúde/Lilacs (BVS), Cumulated Index of Nursing and Allied Health Literature (CINAHL), Cochrane Library, Google Scholar, PubMed, SCOPUS and Web of Science, using a combination of search terms, keywords and free terms. The review question was adjusted to the PICO acronym (Patient/population, Intervention, Control/comparative intervention, Outcome). The selected publications were evaluated according to levels of evidence and grades of recommendation for efficacy/effectiveness studies, as established by the Joanna Briggs Institute. Results Eight hundred and twenty four (824) publications were identified and four studies met the inclusion criteria, of which three analyzed the effect of sponge baths and the effect of immersion baths. Conclusion Sponge baths showed a statistically significant drop in body temperature, while in immersion baths the body temperature remained stable, although they studied late preterm infants.