Transcutaneous CO2 Monitoring in Extremely Low Birth Weight Premature Infants

Extremely low birth weight (ELBW) premature infants are particularly susceptible to hypocarbia and hypercarbia, which are associated with brain and lung morbidities. Transcutaneous CO2 (TcCO2) monitoring allows for continuous non-invasive CO2 monitoring during invasive and non-invasive ventilation and is becoming more popular in the NICU. We aimed to evaluate the correlation and agreement between CO2 levels measured by a TcCO2 monitor and blood gas CO2 (bgCO2) among ELBW infants. This was a prospective observational multicenter study. All infants < 1000 g admitted to the participating NICUs during the study period were monitored by a TcCO2 monitor, if available. For each bgCO2 measured, a simultaneous TcCO2 measurement was documented. In total, 1828 pairs of TcCO2-bgCO2 values of 94 infants were collected, with a median (IQR) gestational age of 26.4 (26.0, 28.3) weeks and birth weight of 800 (702, 900) g. A moderate correlation (Pearson: r = 0.64) and good agreement (bias (95% limits of agreement)):(2.9 [-11.8, 17.6] mmHg) were found between the TcCO2 and bgCO2 values in the 25-70 mmHg TcCO2 range. The correlation between the TcCO2 and bgCO2 trends was moderate. CO2 measurements by TcCO2 are in good agreement (bias < 5 mmHg) with bgCO2 among premature infants < 1000 g during the first week of life, regardless of day of life, ventilation mode (invasive/non-invasive), and sampling method (arterial/capillary/venous). However, wide limits of agreement and moderate correlation dictate the use of TcCO2 as a complementary tool to blood gas sampling, to assess CO2 levels and trends in individual patients.

Oxygenation Instability during Bolus versus Continuous Feeding among Very Low Birth Weight Premature Infants, Supported by Noninvasive Ventilation: A Randomized Prospective Study

OBJECTIVE

 This study aimed to compare oxygenation instability, as documented by the oxygen saturation (SpO₂) histograms, during bolus (over 30 minutes) versus continuous (over 2 hours) feeding among very low birth weight (VLBW) premature infants, supported with noninvasive ventilation (NIV).

STUDY DESIGN

 This was a randomized prospective study. VLBW infants supported with NIV received three consecutive feeds in a random order of bolus-continuous-bolus or continuous-bolus-continuous. During each feed, 30 minutes and 2 hours histograms were documented.

RESULTS

 Twenty-four infants (birth weight [mean ± standard deviation, SD] 820 ± 168 g, gestational age [mean ± SD] 27.0 ± 1.6 weeks) were included in our study (12 infants started with bolus feeding and 12 with continuous feeding) and 72 histograms were obtained (36 during bolus feeding and 36 during continuous feeding). No differences in mean fraction of inspired oxygen (FiO₂), and number of apnea events were observed between the two feeding modes. Oxygenation instability as assessed by time spent in different SpO₂ ranges and histogram types (stable or unstable) was comparable during bolus and continuous feedings. Changing feeding mode from bolus to continuous or vice versa did not significantly change the oxygenation instability of the group, though individual infants did show a consistence response to feeding length changes.

CONCLUSION

 Among VLBW infants supported with NIV, oxygenation instability, as documented by SpO₂ histograms, was comparable between bolus and continuous feedings. Individual infants may benefit from specific feeding length, and this can be easily demonstrated by the SpO₂ histograms.

KEY POINTS

· Feeding length did not affect oxygenation instability of preterm infants on noninvasive respiratory Support.. · Oxygen saturation histograms allow objective quantification of oxygenation instability at the bedside.. · Individual infants benefit from specific feeding length, as demonstrated by SpO2 histograms..

Continuous versus Bolus Gastric Tube Feeding in Very Low Birth Weight Infants Supported with Noninvasive Respiratory Support: A Randomized, Pilot Study

OBJECTIVES

 This study aimed to compare time to full feeding (TFF) between continuous gastric feeding (CGF) and bolus feeding (BF) in very low birth weight (VLBW) infants supported with noninvasive ventilation (NIV) and to evaluate feasibility and identify methodological pitfalls for future large-scale studies.

STUDY DESIGN

 This study is a randomized controlled, prospective, pilot study. VLBW premature infants, supported with NIV, were randomized while still on trophic feeding <20 mL/kg/day to receive feeding over 2 hours of CGF or over 15- to 30-minute BF. The primary outcome was TFF. Analysis was done by intention to treat.

RESULTS

 Overall, 32 infants were included in this analysis, 17 in the CGF group and 15 in the BF group. Infants in the CGF group were significantly younger than the BF group (mean ± standard deviation [SD] gestational age [GA] 26.9 ± 1.2 vs. 28.9 ± 1.5 weeks, respectively). TFF was comparable with median (interquartile range [IQR]) for the two groups, 10.0 (10.0, 19.0) days in the BF group versus 12.0 (9.0, 13.0) days in the CGF group (p = 0.59). Feeding length was not found to significantly affect TFF in multivariate analysis correcting for GA. Groups were comparable in weight gain, gastrointestinal complications, length of NIV, bronchopulmonary dysplasia incidence, and age at discharge. Most infants from both groups (60% of BF and 70% of CGF) required changes in feeding length.

CONCLUSION

 In this pilot study, among VLBW infants supported with NIV, TFF was comparable between the BF and CGF groups. These results should be interpreted with caution due to the small sample size and despite the multivariate analysis correcting for the different GA. Interestingly, most infants required changes in feeding length regardless of their allocation. This feasibility study emphasizes the need for careful attention to randomization and strict feeding protocols including criteria for switching allocation in future large-scale studies aimed at determining the preferred feeding length during NIV in VLBW infants.

KEY POINTS

· Among infants supported with NIV, length of feeding affects gastric venting.. · BF might increase gastrointestinal reflux, while continuous feeding hinders gastric decompression.. · Among infants supported by NIV, feeding tolerance was comparable between bolus and continuous groups..

Effects of neurodevelopmental risk factors on brainstem maturation in premature infants

BACKGROUND

Interpeak latencies (IPL), as measured by the auditory brainstem-evoked responses (ABR) test, represent the conduction time, and therefore the maturation of the brainstem auditory pathway. We aimed to study the effect of various risk factors for the neurodevelopmental delay on the conduction time in the auditory pathway among normal hearing premature infants, at term postmenstrual age (PMA).

METHODS

Retrospective analysis of 239 premature infants (gestational age 32.5 ± 2.1 weeks, birth weight 1827 ± 483 g). Interpeak latencies, demographic data, and risk factors were recorded.

RESULTS

Sex, PMA at ABR test, being small for gestational age (SGA), intraventricular hemorrhage (IVH) or periventricular leukomalacia (PVL), and days of invasive ventilation were found to significantly affect the IPL's in the auditory pathway in a univariate analysis. Multivariable regression analysis revealed that male sex and less advanced PMA at the examination were independent factors associated with prolonged IPL's, while bronchopulmonary dysplasia, IVH or PVL and being SGA shortened the IPL's. Non-invasive mechanical ventilation, did not affect the caudal part of the auditory pathway, despite its high noise level.

CONCLUSIONS

Among various risk factors for the neurodevelopmental delay, male sex was associated with delayed, while IVH or PVL, BPD and SGA could be associated with accelerated auditory brainstem maturation.

IMPACT

Auditory brainstem-evoked response (ABR) test, among normal hearing infants, can serve as a clinical tool to assess brainstem auditory maturation. Different neurodevelopmental risk factors could have different effects on the maturity of the auditory pathway. Male sex is significantly associated with prolonged interpeak latencies (IPL) among preterm and term infants, while intraventricular hemorrhage or periventricular leukomalacia, bronchopulmonary dysplasia, and being small for gestation age may be associated with shortened IPL The corrected age at ABR testing is of significance, among preterm and term infants.

Respiratory morbidity in very low birth weight infants through childhood and adolescence

OBJECTIVE

To describe the long-term (up to 18 years of age) respiratory outcomes of children and adolescents born at very low birth weight (VLBW; ≤1500 g) in comparison with that of children born >1500 g.

METHODS

An observational, longitudinal, retrospective study comparing VLBW infants with matched controls, registered at a large health maintenance organization in Israel. Pulmonary outcomes collected anonymously from the electronic medical files included respiratory illness diagnoses, purchased medications for respiratory problems, office visits with either a pediatric pulmonologist or cardiologist and composite respiratory morbidity combining all these parameters.

RESULTS

Our study included 5793 VLBW infants and 11,590 matched controls born between 1998 and 2012. The majority (99%) of VLBW infants were premature (born < 37 weeks' gestation), while 93% of controls were born at term. The composite respiratory morbidity was significantly higher in VLBW infants compared with controls in all age groups (relative risk [95% confidence interval]: 1 year: 1.22 [1.19-1.26], <2 years: 1.30 [1.27-1.34], 2-6 years: 1.29 [1.27-1.32], 6-12 years: 1.53 [1.47-1.59], 12-18 years: 1.46 [1.35-1.56]; respectively). Both VLBW infants and controls demonstrated a steady decline in the composite respiratory morbidity with aging. In VLBW infants, lower gestational age was associated with higher respiratory morbidity only until 2 years of age and the morbidity declined in each gestational age group until adolescence.

CONCLUSION

Our study confirmed a strong association between VLBW and pulmonary morbidity. The higher prevalence of respiratory composite morbidity in VLBW infants persists over the years until adolescence. The respiratory morbidity is most evident in the first year of life and declines afterward.

Evaluation of audio-voice guided application for neonatal resuscitation: a prospective, randomized, pilot study

OBJECTIVES

To examine whether audio-voice guidance application improves adherence to resuscitation sequence and recommended time frames during neonatal resuscitation.

METHODS

A prospective, randomized, pilot study examining the use of an audio-voice application for guiding resuscitation on newborn mannequins, based on the Neonatal Resuscitation Program (NRP) algorithm. Two different scenarios, with and without voice guidance, were presented to 20 medical personnel (2 midwives, 8 nurses, and 10 physicians) in random order, and their performance videotaped.

RESULTS

Audio-voice guided resuscitation compared with non-guided resuscitation, resulted in significantly better compliance with NRP order sequence (p<0.01), correct use of oxygen supplementation (p<0.01) and performance of MR SOPA (Mask, reposition, suction, open mouth, pressure, airway) (p<0.01), and shortened the time to "positive pressure ventilation" (p<0.01).

CONCLUSIONS

In this pilot study, audio-voice guidance application for newborn resuscitation simulation on mannequins, based on the NRP algorithm, improved adherence and performance of NRP guidelines.

Oxygenation Instability Assessed by Oxygen Saturation Histograms during Supine vs Prone Position in Very Low Birthweight Infants Receiving Noninvasive Respiratory Support

OBJECTIVE

To evaluate the effect of prone vs supine position on the oxygenation instability among very low birth weight (VLBW) infants receiving noninvasive respiratory support, as assessed by the average oxygen saturation (SpO₂) histograms.

STUDY DESIGN

Sixty-nine histograms from 23 VLBW infants were studied prospectively. Each infant was studied during 3 consecutive 3-hour periods of alternating positions; 12 infants started the study while prone and 11 infants started supine, by random order. Histogram classification system was used to quantify oxygenation stability and time spent in different SpO₂ ranges.

RESULTS

The fraction of inspired oxygen values were similar in both positions. Unstable histograms were more common in supine vs prone position (20/34 [59%] vs 10/35 [29%]; P = .02, respectively). Analyzing oxygenation stability as per position change revealed that a change from prone to supine increased oxygenation instability, and supine to prone decreased instability (P = .02). In the supine vs prone position, percent of time spent in SpO₂ ≤80% and <90% was higher (5.0 ± 4.2 vs 2.4 ± 3.4 [P < .001] and 24.1 ± 13.7 vs 13.2 ± 10.0 [P < .001], respectively), and percent of time in SpO₂ >94% was lower (39.7 ± 26.0 vs 52.4 ± 23.4 [P = .04]).

CONCLUSIONS

Prone positioning decreased oxygenation instability and resulted in higher oxygenation among VLBW premature infants on noninvasive respiratory support. SpO₂ histograms allow easy bedside assessment of oxygenation instability, and quantification of the time spent at different SpO₂ ranges.

[ALTERATIONS IN SENSITIVE MEASURES OF CARDIAC FUNCTION IN HEALTHY NEONATES DURING PHOTOTHERAPY]

OBJECTIVES

Phototherapy has been reported to reduce coronary blood flow in neonates but without affecting gross measures of cardiac function. The aim of our current study was to evaluate earlier, more sensitive changes in cardiac function during phototherapy.

METHODS

Nineteen neonates with jaundice treated with phototherapy had Doppler echocardiographic evaluation, before, during and after phototherapy and were compared to 25 matched controls. Sensitive measures for cardiac performance in this study included left ventricular dimension, ventricular Doppler parameters and regional function assessment.

RESULTS

Phototherapy was associated with a significant increase in heart rate. In addition, atrioventricular valve closure to opening interval decreased significantly during phototherapy while ventricular ejection times tended to decrease. However, left and right ventricular filling parameters and outflow velocity parameters, longitudinal tissue-Doppler annular velocities and myocardial performance indices were not affected by phototherapy and were similar to those in controls. Coronary blood velocities and integrals decreased significantly during phototherapy.

CONCLUSIONS

Our study found no differences in early and sensitive measures of cardiac performance including the diastolic and systolic function, despite modestly lower flow in coronary arteries among healthy neonates during phototherapy.

[FUNCTIONAL ECHO IN PRETERM INFANTS - PAST, PRESENT AND FUTURE]

The use of point of care ultrasound to assess cardiovascular function performed by a neonatologist who is not a cardiologist, is gaining interest in the neonatal intensive care unit (NICU). Clinical signs such as heart rate, blood pressure and capillary refill time provide limited insight into the adequacy of systemic blood flow and organ perfusion. Functional echocardiography (echo) enables real time evaluation of cardiac performance, identifying the nature of cardiovascular compromise, guiding therapeutic decisions and monitoring response to treatment. Application of functional echo in the NICU includes assessment of patent ductus arteriosus (PDA), pulmonary hypertension, shock and placement of umbilical catheters. There is evidence implicating that functional echo alters neonatal treatment and may improve outcome. Functional echo does not aim to replace the detailed structural assessments provided by consultative services of pediatric cardiologists. Close collaboration with pediatric cardiology is essential. In the past two years there is an increasing awareness for using functional echocardiography by neonatologists in Israel. Three conferences and an educational workshop were held in Israel with world renowned lecturers. Protocols defining how the exam should be performed were prepared, and agreement was reached with pediatric cardiologists on how to implement the use of functional echo by neonatologists, with the intention to create a distinct group of neonatologists with knowledge and skills in functional echo and a profound understanding of cardiac and respiratory physiology and hemodynamics.

Continuous Noninvasive Carbon Dioxide Monitoring in Neonates: From Theory to Standard of Care

Ventilatory support may affect the short- and long-term neurologic and respiratory morbidities of preterm infants. Ongoing monitoring of oxygenation and ventilation and control of adequate levels of oxygen, pressures, and volumes can decrease the incidence of such adverse outcomes. Use of pulse oximetry became a standard of care for titrating oxygen delivery, but continuous noninvasive monitoring of carbon dioxide (CO₂) is not routinely used in NICUs. Continuous monitoring of CO₂ level may be crucial because hypocarbia and hypercarbia in extremely preterm infants are associated with lung and brain morbidities, specifically bronchopulmonary dysplasia, intraventricular hemorrhage, and cystic periventricular leukomalacia. It is shown that continuous monitoring of CO₂ levels helps in maintaining stable CO₂ values within an accepted target range. Continuous monitoring of CO₂ levels can be used in the delivery room, during transport, and in infants receiving invasive or noninvasive respiratory support in the NICU. It is logical to hypothesize that this will result in better outcome for extremely preterm infants. In this article, we review the different noninvasive CO₂ monitoring alternatives and devices, their advantages and disadvantages, and the available clinical data supporting or negating their use as a standard of care in NICUs.

Adding Paracetamol to Ibuprofen for the Treatment of Patent Ductus Arteriosus in Preterm Infants: A Double-Blind, Randomized, Placebo-Controlled Pilot Study

OBJECTIVE

The objective of this study was to compare the closure rate of hemodynamically significant patent ductus arteriosus (hsPDA) of intravenous ibuprofen + paracetamol (acetaminophen) versus ibuprofen + placebo, in preterm infants of 24 to 31^6/7 weeks postmenstrual age.

STUDY DESIGN

This is a single-center, double-blind, randomized controlled pilot study. Infants were assigned for treatment with either intravenous ibuprofen + paracetamol (n = 12) or ibuprofen + placebo (n = 12).

RESULTS

There was no statistical difference in baseline characteristics of the two groups. Echocardiography parameters were comparable before treatment in both groups. There was a trend toward higher hsPDA closure rate in the paracetamol group in comparison to the placebo group (83 vs. 42%, p = 0.08). No adverse effects, clinical or laboratory, were associated with adding paracetamol.

CONCLUSION

Our pilot study was unable to detect a beneficial effect by adding intravenous paracetamol to ibuprofen for the treatment of hsPDA. Larger prospective studies are needed to explore the positive tendency suggested by our results and to assure safety.

Less is More: Modern Neonatology

Iatrogenesis is more common in neonatal intensive care units (NICUs) because the infants are vulnerable and exposed to prolonged intensive care. Sixty percent of extremely low-birth-weight infants are exposed to iatrogenesis. The risk factors for iatrogenesis in NICUs include prematurity, mechanical or non-invasive ventilation, central lines, and prolonged length of stay. This led to the notion that "less is more." In the delivery room delayed cord clamping is recommended for term and preterm infants, and suction for the airways in newborns with meconium-stained fluid is not performed anymore. As a symbol for a less aggressive attitude we use the term neonatal stabilization rather than resuscitation. Lower levels of oxygen saturations are accepted as normal during the first 10 minutes of life, and if respiratory assistance is needed, we no longer use 100% oxygen but 0.21-0.3 FiO₂, depending on gestational age and the level of oxygen saturation. We try to avoid endotracheal ventilation by using non-invasive respiratory support and administering continuous positive airway pressure early on, starting in the delivery room. If surfactant is needed, non-invasive methods of surfactant administration are utilized. Use of central lines is shortened, and early feeding of human milk is the routine. Permissive hypercapnia is allowed, and continuous non-invasive monitoring not only of the O₂ but also of CO₂ is warranted. "Kangaroo care" and Newborn Individualized Developmental Care and Assessment Program (NIDCAP) together with a calm atmosphere with parental involvement are encouraged. Whether "less is more," or not enough, is to be seen in future studies.