Blanco Delgado, Luis Alejandro¹,²; Escobedo Berumen, Lucía¹,³; Lozano Duau, Corinne¹,⁴; Silva Ramírez, Horacio¹,⁵

Language: English/Spanish [Versión en español]
References: 13
Page: 112-117
PDF size: 275.25 Kb.

ABSTRACT

During the transition period of a newborn, multiple maternal and neonatal factors may be associated with the use of supplemental oxygen during this phase. The objective is to describe the factors associated with the use of supplemental oxygen devices in term newborns in the well-baby nursery of Hospital Español. A descriptive, cross-sectional, observational, retrospective study was conducted through a review of medical records of all term newborns admitted to the well-baby nursery to evaluate the frequency of oxygen device use and its associated factors. The inclusion criteria were newborns aged 37 to 42 weeks of age of both sexes admitted to the physiological nursery, and the exclusion criteria were patients with congenital malformations. Information was collected by reviewing the records of all full-term newborns admitted to the physiological nursery. A total of 379 patients were included, whose mothers had a mean age of 34.2 ± 4.6 years. Ninety-three percent had no significant maternal medical history. Those with maternal medical history, 38.8% had obstetric history, including infections during pregnancy. Of the newborns, 82.1% were delivered by cesarean section, 53% were male, with a mean gestational age at birth of 38.4 ± 0.90 weeks, and an average weight of 2,996 ± 343.7 grams. Of the total patients, 12.9% required supplemental oxygen support in the physiological nursery. 2.6% were admitted to the neonatal intensive care unit. The findings suggest that factors such as cesarean section, advanced maternal age, and metabolic history may influence the need for respiratory intervention.

ABBREVIATIONS:

• PPV = positive pressure ventilation
• CPAP = Continuous positive airway pressure

INTRODUCTION

At birth, the newborn experiences several physiological changes, including the reabsorption of fetal lung fluid from the alveoli and its replacement by air, which occurs during the first breaths and initial crying. Toward the end of gestation, there is an increase in fetal glucocorticoids and thyroid hormones, while stress during labor and birth triggers the release of fetal epinephrine. This epinephrine activates the epithelial sodium channels in the alveoli, reversing their function from secretion to absorption of lung fluid.¹ These biochemical mechanisms generate the clearance of fetal lung fluid, which begins around two or three days before delivery.² It is estimated that nearly 40% of fetal lung fluid is cleared through the lymphatics and drained into the venous system.² Additionally, the mechanical process that occurs when passing through the birth canal also contributes to the clearance of lung fluid.¹

Therefore, elective cesarean delivery increases the probability of requiring supplemental oxygen up to five times.¹ When transpulmonic pressure pushes this fluid into the interstitial space, the amount of protein in the lung tissue decreases, increasing the osmotic pressure difference between plasma and interstitial fluid. Newborns born after labor present a higher amount of protein in plasma compared to those born without this mechanism.²

These processes are completed within 15 to 24 hours after birth and can be divided into three stages:

• 1. Initial reactivity: this phase occurs within the first 30 to 60 minutes of life, during which the newborn experiences intense motor activity, an increase in respiratory rate that can reach between 60 and 100 breaths per minute, and irregular breathing. On physical examination, signs such as nasal flaring, mild grunting, light chest retraction, and/or episodes of apnea can be observed. Neurologically, the newborn appears active and reactive to stimuli, presenting startles, sucking, tremors, crying, and head movements. A decrease in body temperature is common during this phase.³
• 2. Interval of rest or tranquility (from 60 to 120 minutes): this stage is characterized by a notable decrease in motor activity, accompanied by sleep. The heart rate ranges between 100 and 120 beats per minute, and breathing becomes calm, with an average of 50 breaths per minute. It is common for intestinal peristalsis to begin, which can lead to the first bowel movement.³
• 3. Late reactivity (from two up to 15 hours): during this phase, reactivity intensifies, manifesting in episodes of tachycardia, tachypnea, changes in muscle tone and skin color, increased mucus production, gag reflex, and even regurgitation. In this stage, most newborns also experience their first passage of meconium. For this period to develop favorably, it is crucial to ensure an airway free of secretions and an adequate environment to maintain an optimal body temperature.³

Furthermore, it has been shown that an increase in maternal thyrotropin or thyroid-stimulating hormone (TSH) during pregnancy and a lower gestational age at delivery are associated with a lower total free thyroxine (FT4) concentration in the newborn, which decreases lung fluid absorption.⁴ Other maternal risk factors associated with the need for oxygen in the newborn during the first six hours of life have been reported, including: asthma, diabetes mellitus, smoking, administration of large volumes of fluids, prolonged sedation, rupture of membranes greater than 24 hours, and precipitate labor.⁵ Among other risk factors in newborns for requiring oxygen are: macrosomia, male gender, twin pregnancy, full-term or near-term birth, and an Apgar score less than 7.⁶ Cases have also been studied in which thyroxine levels below 14.4 μg/dL represent a risk factor.⁷

In the event that the newborn presents any alteration during their transition period, different devices are available to administer oxygen. The main oxygen delivery devices used in newborns include:

• 1. Positive pressure ventilation devices: include T-piece resuscitators, self-inflating bags, and flow-inflating bags with oxygen reservoirs. These devices are used to provide positive pressure ventilation (PPV) to newborns who are not breathing adequately on their own.^8,9
• 2. Nasal cannula: is a low-flow oxygen delivery system commonly used in stable newborns who require minimal respiratory support. It is less invasive and allows for easier management of the patient.⁹
• 3. Oxygen hood: is used to provide a controlled oxygen environment to the newborn, delivering a stable concentration. It is particularly useful in patients who need higher oxygen concentrations than what a nasal cannula can offer.⁹
• 4. Continuous positive airway pressure (CPAP): is used in newborns, especially preterm infants, who require assistance to keep their airways open. CPAP delivers a continuous flow of air and oxygen to maintain positive pressure in the airways, preventing alveolar collapse.⁹
• 5. Mechanical ventilation: in more severe cases, such as respiratory distress syndrome in preterm infants, mechanical ventilation may be necessary. This involves the use of a ventilator to provide controlled breaths to the newborn.⁹

These devices are selected according to the specific needs of the newborn, the clinical setting, and available resources. The choice of device is guided by the need to provide adequate oxygenation while minimizing potential complications associated with oxygen therapy.

The objective of this study is to describe the factors associated with the use of supplemental oxygen devices in term newborns in the physiological nursery of the Hospital Español.

MATERIAL AND METHODS

An analytical, longitudinal, observational, retrospective study was conducted. Records of live term newborn patients who were admitted to the physiological nursery during the period of June-August 2021 at the Hospital Español, Mexico City, were reviewed. Live newborn patients from 37 to 42 weeks of gestation by ultrasound who were admitted to the physiological nursery of both sexes, with a weight > 2,000 g, were included. Patients with congenital malformations, weight less than or equal to 1,999 g, and preterm infants < 36.6 weeks of gestation (GA) were excluded. Patients with incomplete records were eliminated. Descriptive statistics were performed to obtain measures of central tendency: mean, standard deviation, frequencies, minimum, and maximum; under normality tests with the SPSS program, inferential statistics were performed using χ² for qualitative variables and Student's t-test for quantitative variables, taking p < 0.05 as statistical significance. A logistic regression was performed to look for an association with an adjustment model for age, thereby reducing selection bias.

RESULTS

A total of 379 patients were included, born to mothers with a mean age of 34.2 ± 4.6 years, with a minimum age of 17 years and a maximum of 48 years (Table 1); 93.7% had no significant maternal history. Metabolic history predominated in 6.3%, and 10% presented an obstetric history, with infectious causes predominating (Table 2). Among the births presented, 82.1% were obtained via cesarean section, 53% of the newborns were male, with a mean of weeks of gestation at birth of 38.4 ± 0.90, an average weight of 2,996 ± 343.7 g, and an average height of 48.34 ± 1.6 (Table 3).

Of the total patients, 12.9% required supplemental oxygen support in the physiological nursery, 3.4% required positive pressure ventilation, 12.9% used an oxygen hood, and 15.3% presented respiratory symptoms during their stay in the nursery (Table 4); 2.6% were admitted to the neonatal intensive care unit.

DISCUSSION

The study conducted on the factors associated with the use of supplemental oxygen in term newborns in the physiological nursery of the Hospital Español yields significant findings that highlight the complexity of neonatal transition and its relationship with maternal and neonatal factors. The results demonstrate that 12.9% of newborns required some type of respiratory support, aligning with other similar studies, such as that of Montiel-Morales and colleagues, who reported comparable figures on the prevalence of respiratory interventions in term neonates.³ This underscores the need for close monitoring during this critical period of adaptation to extrauterine life.

Maternal history plays a crucial role in the respiratory transition of the neonate. In this study, metabolic and obstetric history, such as infections in the third trimester, showed a statistically significant association with the use of supplemental oxygen (p < 0.05). These observations coincide with what was reported by Carpena and his team, who pointed out that maternal conditions such as hypothyroidism and gestational diabetes can alter neonatal respiratory physiology, increasing the risk of transient tachypnea.⁵ Furthermore, according to Villanueva-García, proper management of these conditions during pregnancy could mitigate respiratory risks in the neonate.²

Advanced maternal age has also been identified as a potential risk factor. Although this study did not find a significant association between an age greater than 37 years and the need for respiratory support, previous research, such as that by Mühlhausen Muñoz and González Bravo (2016), has linked maternal age to an increased risk of neonatal complications.¹⁰ Likewise, factors such as smoking and the use of large volumes of intravenous fluids during labor, described by the IMSS Clinical Practice Guideline (2016), should also be considered in future research.⁶

Regarding neonatal factors, the study highlighted that the majority of newborns who required supplemental oxygen were born by cesarean section (79.6%). Although no statistical significance was found in the association between the mode of delivery and the use of oxygen (p = 0.630), the literature suggests that the lack of thoracic compression during cesarean delivery can hinder the clearance of fetal lung fluid, as described by Coto Cotallo and colleagues.⁴ In addition, Reuter and his group highlight that an Apgar score less than 7 and macrosomia are neonatal factors associated with a higher risk of respiratory distress, emphasizing the need for a comprehensive evaluation at birth.¹¹

On the other hand, Alhassen and his team emphasize that transient tachypnea of the newborn is one of the most common causes of respiratory distress in term neonates, attributable to delayed reabsorption of lung fluid.¹ This process can be aggravated by conditions such as hypothyroxinemia, described by Ulanovsky and his group as an important predisposing factor.⁷ Although this study did not find a direct correlation with maternal hypothyroidism, prospective studies could better clarify this relationship.

The retrospective design of this study presents inherent limitations, such as reliance on the quality of medical records. Furthermore, the absence of information regarding the type of anesthesia used in cesarean sections and other perinatal factors limits the interpretation of some findings. Prospective studies could offer more conclusive data on the observed associations.

This study emphasizes the importance of identifying both maternal and neonatal risk factors to implement appropriate preventive measures and monitoring. Early detection of signs of respiratory distress, such as polypnea and desaturation, is essential to avoid major complications and optimize neonatal outcomes. Furthermore, according to Vento, an appropriate and moderate use of supplemental oxygen is crucial to avoid adverse effects, such as lung injury or oxidative stress in the neonate.¹²

It is recommended to conduct prospective studies that explore in greater depth the underlying mechanisms of the relationship between maternal and neonatal factors and the need for respiratory support. Additionally, it would be valuable to analyze the impact of specific interventions, such as the use of prenatal steroids in mothers at risk for cesarean delivery, to improve neonatal outcomes. Moreira and colleagues also suggest that comparative studies on oxygen administration and positive pressure ventilation could provide useful data to standardize clinical protocols.¹³

CONCLUSIONS

This study provides a detailed view of the factors associated with the use of supplemental oxygen in term newborns in the physiological nursery of the Hospital Español. The results indicate that, although the majority of newborns did not require significant respiratory interventions, 12.9% needed some type of support, which underscores the importance of continuous vigilance during the neonatal transition period. The findings suggest that factors such as cesarean section, advanced maternal age, and metabolic history may influence the need for respiratory intervention.

It is relevant to highlight that signs of respiratory distress in the first moments of life can be transient, but their proper management is crucial to prevent long-term complications. Early interventions and rapid identification of respiratory symptoms, such as polypnea and desaturation, are essential to ensure a successful neonatal transition. Therefore, continuous training of healthcare professionals in recognizing signs of respiratory distress and in managing appropriate interventions is essential.

Finally, the results obtained highlight the need to maintain well-established protocols for neonatal monitoring, as well as the importance of a comprehensive evaluation of the newborn, taking into account both maternal and neonatal factors, to optimize care and ensure a safe transition to extrauterine life.

REFERENCES

1. Alhassen Z, Vali P, Guglani L, Lakshminrusimha S, Ryan RM. Recent advances in pathophysiology and management of transient tachypnea of newborn. J Perinatol. 2021; 41 (1): 6-16. doi: 10.1038/s41372-020-0757-3.

2. Villanueva-García D. Programa de actualización continua en neonatología. Libro 2: Insuficiencia respiratoria neonatal. 1st ed. México: Intersistemas; 2016. p. 2.

3. Montiel-Morales D, Ferreira-Jaime F, Rendón-Macías M. Comparación del periodo de transición en recién nacidos obtenidos de parto en agua y parto en seco. Estudio de cohortes. Rev Mex Pediatr. 2016; 83 (5): 148-153. Available from: https://www.medigraphic.com/pdfs/pediat/sp-2016/sp165b.pdf

4. Coto-Cotallo GD, Sastre L, Fernández-Colomer B, Caro Á, Fernández I. Recién nacido a término con dificultad respiratoria: enfoque diagnóstico y terapéutico. Protocolos Diagnóstico Terapeúticos de la AEP: Neonatología. 2003: 285-305.

5. Carpena-Lucas PJ, Calvo-Rigua F, Pons-Fernández N, Rey-Simón R, Sanz-Gallur J, Casañ-Fernández R. Seguimiento de recién nacidos hijos de madres con hipotiroidismo en el embarazo. Rev Esp Endocrinol Pediátr. 2015; 6 (2): 4-11. Disponible en: https://www.endocrinologiapediatrica.org/revistas/P1-E16/P1-E16-S594-A274.pdf

6. Guía de Práctica Clínica. Diagnóstico y Tratamiento de la Taquipnea Transitoria del Recién Nacido. Ciudad de México: Instituto Mexicano del Seguro Social; 03/11/2016. Disponible en: https://www.imss.gob.mx/sites/all/statics/guiasclinicas/044GER.pdf

7. Ulanovsky I, Smolkin T, Almashanu S, Mashiach T, Makhoul IR. Hypothyroxinemia and risk for transient tachypnea of newborn. J Pediatr. 2016; 179: 266-268.e1. doi: 10.1016/j.jpeds.2016.08.061.

8. Jeejeebhoy FM, Zelop CM, Lipman S, Carvalho B, Joglar J, Mhyre JM et al. Cardiac arrest in pregnancy: a scientific statement from the American Heart Association. Circulation. 2015; 132 (18): 1747-1773. doi: 10.1161/CIR.0000000000000300

9. Hinder M, Tracy M. Newborn resuscitation devices: the known unknowns and the unknown unknowns. Semin Fetal Neonatal Med. 2021; 26 (2): 101233. doi: 10.1016/j.siny.2021.101233.

10. Mühlhausen Muñoz G, González Bravo A. Guías de Práctica Clínica Hospital San José. 2016. Available from: http://www.manuelosses.cl/BNN/gpc/Manual%20Neo_H.SnJose_2016.pdf

11. Reuter S, Moser C, Baack M. Respiratory distress in the newborn. Pediatr Rev. 2014; 35 (10): 417-429. doi: 10.1542/pir.35-10-417

12. Vento M. Oxygen supplementation in the neonatal period: changing the paradigm. Neonatology. 2014; 105 (4): 323-331.

13. Moreira ME, Pereira APE, Gomes Junior SC, Guinsburg R, de Almeida MFB, Gama SG et al. Factors associated with the use of supplemental oxygen or positive pressure ventilation in the delivery room, in infants born with a gestational age ≥ 34 weeks. Reprod Health. 2016; 13 (Suppl 3): 116.

AFFILIATIONS

¹ Hospital Español. Ciudad de México, México.

² Médico residente de primer año de Neonatología. ORCID: 0009-0002-4698-6517

³ Médico adscrito al Servicio de Gastroenterología Pediátrica. ORCID: 0000-0001-6094-5573

⁴ Médico adscrito al Servicio de Neonatología. ORCID: 0009-0002-3561-5454

⁵ Jefe de Servicio de Pediatría. ORCID: 0009-0008-7833-9668

If you wish to consult the supplementary data for this article, please contact editorial.actamedica@saludangeles.mx

CORRESPONDENCE

Luis Alejandro Blanco Delgado. Correo electrónico: L.blanco1992@gmail.com

Received: 2025-01-10. Accepted: 2025-01-28.