Fluid and electrolyte balance in extremely preterm infants <24 weeks of gestation in the first week of life

Nursing care of infants born extremely preterm

With improving survival at the lowest gestations an increasing number of tiny and vulnerable infants are being cared for, and optimal outcomes require an approach to care that takes their specific characteristics into account. These include immature organ function and a risk for iatrogenic injury, and parental/familial strain due to the high degree of uncertainty, infant-mother separation, and long hospital stay. While the challenges in providing nursing care to these infants are obvious it is also clear that this field has tremendous potential to influence both short and long-term outcomes of this population. This mini-review discusses aspects of the nursing care provided to infants born at the very lowest gestations and their families, with focus on doing less harm by establishing an adequate care environment, actively promoting parental closeness and care-giving, and conservative skin care.

Practical procedures for the delivery room resuscitation of micropreemies

There are no standardized procedures for the resuscitation of micropreemies but respiratory and circulatory stabilization immediately after birth should be prioritized. Without aggressive support by positive pressure ventilation, establishing effective respiration among micropreemies is not possible. The first step in postnatal stabilization is initiated by positive airway pressure with a bag and mask. Once the heart rate increases above 100 beats/m, intratracheal intubation should be achieved because it is unusual for a micropreemie to breathe spontaneously or by non-invasive respiratory support for a protracted duration. Until further information is available, initial FiO₂ should be between 0.3 and 0.6, and titrated to achieve SpO₂ obtained from healthy term infants for the first 10 min of life. Temperature control of infants is also critical for successful resuscitation and heat-loss minimizing procedures should be used e.g. with insulating bags. After securing the intratracheal tube, the infants should be transferred to the NICU for further procedures, including pulmonary surfactant installation and umbilical cord catheterization. Procedures in a delivery room under a radiant warmer should be limited to the initial resuscitation. In NICUs, the infants should be placed into a closed incubator to maintain high environmental temperature and humidity as well as decrease exposure to intervention and noise. Increased number of staff will also be needed to stabilize the infants further in the NICU. Finally, appropriate equipment (e.g. appropriate sized laryngoscopes) should be made readily available, along with regular practical training and education, whether in person or through SIM courses which are essential for all staff to achieve competence in successful resuscitation of the newborn micropreemie.

The Impact of Restricted versus Liberal Early Fluid Volumes on Plasma Sodium, Weight Change, and Short-Term Outcomes in Extremely Preterm Infants

The optimal fluid requirements for extremely preterm infants are not fully known. We examined retrospectively the fluid intakes during the first week of life in two cohorts of extremely preterm infants born at 22-26 weeks of gestation before (n = 63) and after a change from a restrictive to a more liberal (n = 112) fluid volume allowance to improve nutrient provision. The cohorts were similar in gestational age and birth weight, but antenatal steroid exposure was more frequent in the second era. Although fluid management resulted in a cumulative difference in the total fluid intake over the first week of 87 mL/kg (p < 0.001), this was not reflected in a mean weight loss (14 ± 5% at a postnatal age of 4 days in both groups) or mean peak plasma sodium (142 ± 5 and 143 ± 5 mmol/L in the restrictive and liberal groups, respectively). The incidences of hypernatremia (>145 and >150 mmol/L), PDA ligation, bronchopulmonary dysplasia, and IVH were also similar. We conclude that in this cohort of extremely preterm infants a more liberal vs. a restricted fluid allowance during the first week had no clinically important influence on early changes in body weight, sodium homeostasis, or hospital morbidities.

Fluid management considerations in extremely preterm infants born at 22-24 weeks of gestation

Emerging data regarding the encouraging outcomes of extremely preterm infants from centers taking active approaches to the care of these infants have prompted dialogue regarding optimal medical management. Among the multitude of decisions providers make in caring for extremely premature infants is the prescribing of parenteral fluids. Surprisingly, there are limited data to guide evidenced-based approaches to fluid and electrolyte management in this population. Immaturity of renal function and skin barriers contribute to the impaired capacity of the preterm infant to maintain salt and water homeostasis. This perspective paper highlights developmental physiological properties of the kidney and skin, which the provider needs to understand to provide parenteral fluid therapy. Additionally, we provide recommendations for initial fluid and electrolyte management of the preterm infant based on novel data as well as the published literature.

Creating experiences from active treatment towards extremely preterm infants born at less than 25 weeks in Japan

Treatment for extremely preterm infants born at less than 25 weeks of gestation in Japan was initiated mainly due to the amendment of the Maternal Health Act lowering the upper limit of abortion from 24 weeks to 22 weeks in 1990. Five years after the amendment, the Japanese national government started a nationwide project to improve the perinatal care system. Once selected perinatal centers reported improvements in survival rates, more centers have adopted aggressive treatments. They have accumulated their knowledge by experiencing the treatment of infants with a limit of viability. As a result, more than 50% of infants born even at 22 weeks of gestation can survive to discharge currently. This progress has resulted from the accumulation of experience at each perinatal center rather than the results from clinical trials. Furthermore, these experiences have been standardized to some extent through sharing information.

Hemodynamic support of the micropreemie: Should hydrocortisone never be left out?

Hemodynamic support for a micropreemie is critically important for preventing mortality and morbidity. An essential consideration in hemodynamic support is insufficient transition from fetal to neonatal circulation and inadequate cortisol production. The first 72 h of life are the most critical, especially when myocardial function is immature and impaired. Therefore, there is a need to determine and adjust preload, myocardial contractility, and afterload appropriately using repeated functional echocardiography. In addition, if myocardial function is not responsive to these attempts at hemodynamic management, hydrocortisone must be used to minimize the suboptimal perfusion burden. Fetal cortisol production is supported by a supply of progesterone from the placenta, and postnatally, adrenal cortisol production in the extremely preterm infant may be inadequate if the infant is placed under excessive stress. This leads to relative adrenal insufficiency which may last for up to several weeks after birth and lead to late-onset circulatory collapse, necessitating treatment with physiological doses of hydrocortisone.

The Impact of 2 Weight-Based Standard Parenteral Nutrition Formulations Compared With One Standard Formulation on the Incidence of Hyperglycemia and Hypernatremia in Low Birth-Weight Preterm Infants

BACKGROUND

Standardized parenteral nutrition (PN) formulations are used in at-risk neonates to provide nutrition immediately following birth. However, evidence for the optimal formulation(s) to maximize growth while reducing the risks of glucose and electrolyte abnormalities is limited.

PURPOSE

The purpose of this study was to compare the rates of hypernatremia and hyperglycemia with 2 weight-based standardized PN formulations versus one standard PN in low birth-weight preterm neonates.

METHODS

This was a single-center observational study of infants less than 1800 g birth weight and less than 37 weeks' gestation who received standardized PN in the first 48 hours of life. Patients in the weight-based PN group were compared with a historical group of patients receiving single standard PN. Rates of hypernatremia and hyperglycemia were compared by χ2 analysis.

RESULTS

There was a nonsignificant (P = .147) reduction in hypernatremia in the weight-based PN group (9 of 87; 10.3%) compared with the single PN group (16 of 89; 18.0%). However, hyperglycemia was significantly more frequent in the weight-based group than in the single PN group (24.1% vs 12.4%, P = .035).

IMPLICATIONS FOR PRACTICE

The 2 weight-based PN standardized formulations studied did not significantly decrease the incidence of hypernatremia or hyperglycemia.

IMPLICATIONS FOR RESEARCH

Future studies to determine optimal standardized PN to provide early nutrition in high-risk neonates are warranted.

Case Report: Intact Survival of a Marginally Viable Male Infant Born Weighing 268 Grams at 24 Weeks Gestation

We report the case of a preterm small for gestational age male infant born at 24 weeks of gestation with a birth weight of 268 g who was discharged from our hospital without the requirement for home oxygen therapy or tube feeding. He did not experience severe intraventricular hemorrhage, periventricular leukomalacia, hearing disability, or any other serious complications. At that time (February 2019), according to the University of Iowa's Tiniest Babies Registry, he was the tiniest male infant in the world to survive without any serious complications other than severe retinopathy of prematurity that required laser therapy. Although the survival rate of infants with extremely low birth weight is improving worldwide, a high mortality rate and incidence of severe complications remain common for infants weighing <300 g at birth, particularly in male infants. In recent years, there have been frequent discussions regarding the ethical and social issues involved in treating extremely preterm infants weighing <400 g. Despite the challenges, reports of such infants surviving are increasing. Neonatal medicine has already achieved great success in treating infants weighing 400 g or more at birth. However, lack of evidence and experience may make physicians reluctant to treat infants weighing less than this. The present case demonstrates that intact survival of a marginally viable male infant with a birth weight of <300 g is possible with minimal handling and family involvement beginning shortly after birth. Our detailed description of the clinical course of this case should provide invaluable information to physicians around the world who treat such infants. This report will aid in the progress of neonatal medicine and help to address many of the social and ethical issues surrounding their care.

Effect of blood transfusion on intestinal blood flow and oxygenation in extremely preterm infants during first week of life

BACKGROUND

Extremely preterm infants receive frequent blood transfusions in the first week of life. The aim of this study was to measure the effect of blood transfusion on intestinal blood flow and oxygenation during the first week of life in extremely preterm infants.

STUDY DESIGN AND METHODS

Superior mesenteric artery (SMA) peak systolic velocity (PSV) and diastolic velocities were measured 30 to 60 minutes before and after transfusion. Splanchnic tissue hemoglobin index (sTHI), splanchnic tissue oxygenation index (sTOI), and splanchnic fractional tissue oxygen extraction (sFTOE) were measured continuously from 15 to 20 minutes before to after transfusion along with vital variables.

RESULTS

Twenty infants were studied (median gestational age, 26 weeks). Ten infants were partially fed (15-68 mL/kg/day). Heart rate and SaO2 remained unaltered; blood pressure increased significantly (p < 0.01) after transfusion. Mean SMA PSV (p = 0.63) and diastolic velocity (p = 0.65) remained unaltered. Mean pretransfusion SMA PSV was similar in partially fed (0.78 m/sec) compared to unfed infants (0.52 m/sec; p = 0.06) and the response to transfusion was not dissimilar. There was a significant increase in sTHI (mean difference, 32.3%; p < 0.01) and sTOI (14.6%; p = 0.03) and decrease in sFTOE (22.1%; p < 0.01) after transfusion. There was no significant difference in sTHI or sTOI between fed and unfed infants and their response to transfusion.

CONCLUSIONS

Blood transfusion increased blood pressure and intestinal tissue oxygenation but did not alter blood flow velocities. Partial feeding had no impact on intestinal blood flow and tissue oxygenation changes.

Biological Impact of Recent Guidelines on Parenteral Nutrition in Preterm Infants

OBJECTIVES

Recent guidelines for preterm neonates recommend early initiation of parenteral nutrition (PN) with high protein and relatively high caloric intake. This review considers whether these changes could influence homeostasis in very preterm infants during the first few postnatal weeks.

METHODS

This systematic review of relevant literature from searches of PubMed and recent guidelines was reviewed by investigators from several perinatal centers in France.

RESULTS

New recommendations for PN could be associated with metabolic acidosis via the increase in the amino acid ion gap, hyperchloremic acidosis, and ammonia acidosis. The introduction of high-intake amino acids soon after birth could induce hypophosphatemia and hypercalcemia, simulating a "repeat feeding-like syndrome" and could be prevented by the early intake of phosphorus, especially in preterm infants born after fetal growth restriction. Early high-dose amino acid infusions are relatively well tolerated in the preterm infant with regard to renal function. Additional studies, however, are warranted to determine markers of protein intolerance and to specify the optimal composition and amount of amino acid solutions.

CONCLUSIONS

Optimal PN following new guidelines in very preterm infants, despite their demonstrated benefits on growth, may induce adverse effects on ionic homeostasis. Clinicians should implement appropriate monitoring to prevent and/or correct them.

Airway humidification with a heated wire humidifier during high-frequency ventilation using Babylog 8000 plus in neonates

OBJECTIVE

Little data are available on airway humidity during high-frequency ventilation (HFV). Our purpose is to evaluate the airway humidification during HFV.

METHODS

We examined the airway humidification and temperature in a neonatal HFV system using Babylog 8000 plus. The absolute humidity (AH), relative humidity (RH), and temperature at different sites and under different HFV conditions were compared with those during conventional intermittent positive pressure ventilation (IPPV).

RESULTS

The mean AH and RH at the patient end of the respiratory circuit under 37 degrees C in the humidification chamber (HC) during HFV were less than 35 mg/L and 65%, respectively, while those during IPPV were 42.3 mg/L and 96.8%, respectively. The humidification at the outlet of the HC was similar results. Moreover, during HFV an increase in the bias-flow of ventilator led to a further decrease in the humidity at the patient end of respiratory circuit and the outlet of HC. It was necessary to set the temperature in the HC at >39 degrees C to maintain adequate humidity at the HC and the patient end of respiratory circuit during HFV. An increase in the incubator temperature led to an increase in the temperature at the patient end of the respiratory circuit. The temperature at the patient end of the respiratory circuit was about 39-40 degrees C when the incubator temperature was 35-37 degrees C.

CONCLUSIONS

The airway humidification at the patient end of respiratory circuit and the outlet of HC in HFV were poorer than those in IPPV. However, the adequacy of humidification and safety in HFV remain to be demonstrated in clinical practice.