Infant respiratory distress syndrome

Infant respiratory distress syndrome
Other names	Neonatal respiratory distress syndrome [1]
Chest X-ray of a case of IRDS, with fine granular opacities, air bronchograms and bell-shaped thorax
Specialty	Pediatrics, obstetrics

Infant respiratory distress syndrome (IRDS), also called respiratory distress syndrome of newborn, or increasingly surfactant deficiency disorder (SDD),

IRDS is distinct from pulmonary hypoplasia, another leading cause of neonatal death that involves respiratory distress.^{[citation needed]}

The European Consensus Guidelines on the Management of Respiratory Distress Syndrome highlight new possibilities for early detection, and therefore treatment of IRDS.^[8] The guidelines mention an easy to use rapid point-of-care predictive test that is now available^[9] and how lung ultrasound, with appropriate training, expertise and equipment, may offer an alternative way of diagnosing IRDS early.^[10]

Signs and symptoms

IRDS begins shortly after birth and is manifested by fast breathing (more than 60 breaths per minute), a fast heart rate, chest wall retractions (recession), expiratory grunting, nasal flaring, and blue discoloration of the skin during breathing efforts.^{[citation needed]}

As the disease progresses, the baby may develop ventilatory failure (rising carbon dioxide concentrations in the blood) and prolonged cessations of breathing ("apnea"). Whether treated or not, the clinical course for the acute disease lasts about two to three days. During the first day, the child worsens and requires more support. During the second day, the baby may be remarkably stable on adequate support and resolution is noted during the third day, heralded by a prompt diuresis. Despite huge advances in care, IRDS remains the most common single cause of death in the first month of life in the developed world. Complications include metabolic disorders (acidosis, low blood sugar), patent ductus arteriosus, low blood pressure, chronic lung changes and bleeding in the brain. The syndrome is frequently complicated by prematurity and its additional effect on other organ functions.^[11]

Related disorders

Acute respiratory distress syndrome (ARDS) has some similarities to IRDS. Transient tachypnea of the newborn presents with respiratory distress syndrome in the Term child.^[12]

Histopathology

The characteristic histopathology seen in babies who die from RDS was the source of the name "hyaline membrane disease". Waxlike layers of hyaline membrane line the collapsed alveoli of the lung. In addition, the lungs show bleeding, overdistention of airways, and damage to the lining cells.^{[citation needed]}

Pathophysiology

The lungs of infants with respiratory distress syndrome are developmentally deficient in a material called surfactant, which helps prevent the collapse of the terminal air spaces (the future site of alveolar development) throughout the normal cycle of inhalation and exhalation. This deficiency of surfactant is related to inhibition from the insulin that is produced in the newborn, especially those of diabetic mothers.^[13]

Pulmonary surfactant is a complex system of

The diagnosis is made by the clinical picture and the chest X-ray, which demonstrates decreased lung volumes (bell-shaped chest), absence of the thymus (after about six hours), a small (0.5–1 mm), discrete, uniform infiltrate (sometimes described as a "ground glass" appearance or "diffuse airspace and interstitial opacities") that involves all lobes of the lung and air-bronchograms (i.e. the infiltrate will outline the larger airways passages, which remain air-filled). In severe cases, this becomes exaggerated until the cardiac borders become indiscernible (a 'white-out' appearance).^{[citation needed]}

Point-of-care lung maturity test

To improve clinical outcomes very early treatment with surfactant is necessary.^[14] However, only about half of infants with a gestational age (GA) below 30 weeks need surfactant treatment^[15][16] and prophylactic surfactant treatment increases the combined mortality and incidence of Bronchopulmonary Dysplasia (BPD) contrary to selective rescue surfactant treatment.^[17] Therefore, there is a need for a rapid diagnostic test to guide early targeted surfactant treatment.^[18]

Professor Henrik Verder has worked with lung-maturity diagnostics on gastric aspirates obtained at birth for over 15 years. With the introduction of surfactant treatment for IRDS, Henrik Verder developed additional lung maturity tests based on gastric aspirates (GAS); for example, the microbubble stability test^[19] and lamellar body counts (LBC)^[20] as well as a large randomised trial using lamellar body counts to guide surfactant treatment.^[21] However, a common problem with all these methods is dilution with foetal urine. Additionally, the methods are time‐consuming laboratory tests and are too slow to be used as a point‐of‐care test (POC) to guide surfactant treatment.

Professor Henrik Verder, in collaboration with chemometric scientist Agnar Hoskuldsson, developed a rapid point-of-care method for predicting IRDS by measuring the lecithin-sphingomyelin ratio (L/S) in gastric aspirate (GA).^[9] The new method, which is based on mid‐red Fourier Transform Infrared spectroscopy (FTIR),^[22] was shown to measure the L/S ratio at birth with a high sensitivity.^[9] This rapid bedside test for surfactant components in gastric aspirate is also now available, and clinical trials of this new point-of-care test to determine surfactant need at birth are underway.^[23][9]

Lung ultrasound

Lung ultrasound, with appropriate expertise, equipment and training, may offer another alternative way of diagnosing IRDS at an earlier stage, without apparently resulting in more infants overall being treated.^[10]

Prevention

Giving the baby's mother

Infant respiratory distress syndrome (IRDS) is the leading cause of death in premature infants.[26]  Despite only 1% of all birth complications being attributed to respiratory distress syndrome, there is a significantly higher prevalence in prematurely born babies.^[27] Incidence rates of IRDS in premature infants born at 30 weeks of gestational age (GA) are at 50%, and rise even higher to 93% for infants born prematurely at 28 weeks of gestational age or younger.^[27] IRDS is diagnosed within hours of delivery and usually leads to morbidity and mortality in preterm infants. There are many risk factors that can potentially cause IRDS. The most common risks factors that can potentially cause IRDS include male gender, white race, late preterm delivery, maternal diabetes, perinatal hypoxia (exposure to low oxygen) and ischemia (decreased blood flow), and low birth weight.^[28] Seventy percent of babies diagnosed with respiratory distress syndrome are born between 29 and 34 weeks of gestational age and are 55% more likely to be male.^[27] A study conducted at the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network studied premature infants born between 22 and 37 weeks and the outcomes leading to IRDS. This study was conducted from 2002 to 2008. The incidence rate of IRDS for 24 weeks was 98%, for 34 weeks the incidence is 5%, and for 37 weeks the incidence rate was less than 1%. The results demonstrate that the incidence of IRDS increases with decreasing age at birth.^[29]

According to a study from the University of Miami's Department of Pediatrics and Division of Neonatology, from the time range of 2003 to 2014, respiratory distress syndrome prevalence jumped from 170 per 1000 preterm live births to 360 per 1000 preterm live births nationwide in the United States.^[30] This study population's duration under hospital care averaged 32 days in 2003, increasing by nearly a week to 38 days in 2014.^[30] Additionally, this study yielded average prevalence rates of 260 cases per 1000 livebirths from the years of 2003 to 2014,^[30] which coincided with the results yielded by a report from the Vermont Oxford Network in 2008 of 300 per 1000 livebirths.^[31]

Treatment

Oxygen is given with a small amount of

The INSURE method has been shown, through meta-analysis, to successfully decrease the use of mechanical ventilation and lower the incidence of bronchopulmonary dysplasia (BPD).^[36] Since its conception in 1989, the INSURE method has been academically cited in more than 500 papers.^[37] The first randomised study involving the INSURE method was published in 1994^[38] and a second randomised study in infants less than 30 weeks gestation was published by the group in 1999.^[39] Based on the INSURE method, Henrik Verder has since developed a rapid bedside test that predicts IRDS at birth.^[8]

Extracorporeal membrane oxygenation (ECMO)

• In 1963,
  Jacqueline Kennedy, died of RDS two days after his premature birth at 34 weeks gestation.^[41]
• Two daughters of Dominick Dunne and his wife Ellen Griffin Dunne died of RDS, one in 1958 and one in 1963.^[42]

See also

• Bubble CPAP
• Bronchopulmonary dysplasia
• Pulmonary hypoplasia
• Surfactant metabolism dysfunction
• Surfactant therapy
• Wilson–Mikity syndrome

References