Respiratory Distress in the Newborn

General Presentation

Respiratory distress is a clinical condition characterized by the presence of one or more signs of increased work of breathing including: tachypnea, nasal flaring, grunting, and chest wall retractions. It is vital to recognize these signs early and alleviate respiratory distress in the newborn because the patient can rapidly deteriorate to respiratory failure. Some of the underlying causes of respiratory distress include upper and lower airway diseases, lung diseases, and poor respiratory effort secondary to central nervous system dysfunction. Risk factors for developing respiratory distress vary depending on the underlying cause.

Questions to Ask

Initial assessment of newborns in respiratory distress should begin by evaluating the ABC’s (airway, breathing, circulation). Only then should you move onto the history and physical exam. Even though respiratory distress is a clinical sign, details from the patient’s history are critical in formulating the differential diagnosis. When faced with a newborn, asking about the pregnancy, labor and delivery are especially important since these questions can elicit risk factors for the various causes of respiratory distress in the newborn.

History of Presenting Illness

Onset (acute vs. insidious)
Timing
Severity (improving, deteriorating)
Associated symptoms (cough, relation to feeds, emesis etc.)

Past Medical History

Maternal/Obstetric History: prenatal fetal assessments (ultrasound, amniocentesis, triple screen), Group B Streptococcus (GBS) status, maternal diabetes, infections, toxic exposures, medications
Labour and Delivery: fetal monitoring (HR, beat to beat variability, decelerations), prolonged rupture of membranes, maternal fever, vaginal delivery vs. Caesarian section, gestational age, use of forceps/vacuum, complications (trauma, meconium, asphyxia)
Neonatal period: APGAR scores, need for resuscitation

Family History

Lung disorders
Congenital heart disease
Early childhood deaths
Consanguinity

Differential Diagnosis

Pulmonary

Respiratory distress syndrome/hyaline membrane disease; transient tachypnea of the newborn/wet lung; meconium aspiration syndrome; pleural effusion; pneumothorax: congenital lung malformations

Infectious

Sepsis; pneumonia (GBS, other infectious organisms)

Cardiac

Congenital heart disease; persistent pulmonary hypertension of the newborn

Hematologic

Blood loss/anemia
Polycythemia

Anatomic

Tracheoesophageal fistula
Congenital diaphragmatic hernia
Upper airway obstruction

Metabolic

Hypoglycemia
Inborn errors of metabolism
Acidosis
Neurologic

CNS

Trauma or intracranial bleed
Drug withdrawal syndromes
Seizures

MSK

Chest wall deformities

Physical Examination

In the assessment of a newborn in respiratory distress, you should perform a focused respiratory exam, as well as exams of the other systems that are part of the differential diagnosis:

Vital signs:

Tachypnea (RR >60/minute), tachycardia (HR >160/minute), decreased oxygen saturation, temperature instability

Inspection (the most important aspect of the physical exam):

Increased work of breathing, cyanosis, pallor, scaphoid abdomen, meconium staining, (clubbing may be difficult to detect in newborns), asymmetric chest wall movement (suggestive of tension pneumothorax)

Palpation:

Tracheal deviation, displaced apical beat, thrill may be palpable in the precodium

Percussion:

Usually not very informative in the newborn (may have dullness to percussion with consolidation, or hyper-resonance with a pneumothorax)

Auscultation:

Make sure you auscultate over all the lung zones (don’t forget about the right middle lobe). Listen for air entry (symmetry and adequacy of air exchange), bronchial/vesicular air sounds, adventitious sounds (crackles, wheeze), as well as possible bowel sounds.
It is important to also take the time to listen to the heart sounds for the presence of any pathological murmurs.

Special Tests:

Transillumination of the chest wall is used to quickly detect a pneumothorax

Investigations

Blood work:

Arterial blood gas (ABG) or capillary blood gas
CBC with differential, blood cultures
Blood glucose
Other blood work will depend on the differential diagnosis

Imaging:

Chest x-ray (CXR)
Echocardiogram/ECG (if indicated)

Click here for summary table

Appendix

Increased work of breathing:

Tachypnea: respiratory rate >60/minute (increased respiratory rate to maintain ventilation in the face of decreased tidal volume)
Grunt: partial closure of glottis during expiration (attempt to maintain lung volume and allow for adequate gas exchange)
Nasal flaring: attempt to decrease airway resistance
Suprasternal retractions/ tracheal tug: suggests upper airway obstruction
Subcostal retractions: less specific sign, associated with either pulmonary or cardiac disease

Respiratory failure: inadequate oxygenation or ventilation of tissues

Oxygenation: supply of adequate oxygen to tissues
Ventilation: removal of carbon dioxide from tissues
Signs of respiratory failure include cyanosis, gasping, choking, apnea and stridor

Pulmonary Surfactant: Mixture of lipids and proteins produced by type II pneumocytes in the lung. Surfactant creates a thin layer within the alveoli that decreases surface tension, preventing collapse of alveoli. This increases the amount of available surface area for gas exchange.

References

Aly H. Respiratory Disorders in the Newborn: Identification and Diagnosis. Pediatrics in Review. Vol 25(6), June 2004: 201-208.

Behrman, RE, and RM Kliegman. Nelson Essentials of Pediatrics. W.B. Saunders Company Philadelphia. 2002.

Bickley, LS. Bates’ Gude to Physical Examination and History Taking. Lippincott Williams & Wilkins. Philadelphia. 2003.

Goldbloom, RB. Pediatric Clinical Skills. Saunders. Philadelphia. 2003

Molckovsky, A and Pirzada (eds). The Toronto Notes Review for the MCCQE. Toronto Notes Medical Publishing 2004.

Acknowledgements

Written by: Shir Minnes

Edited by: Jeff Bishop