Click for pdf: Respiratory Distress
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)
- 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
- Lung disorders
- Congenital heart disease
- Early childhood deaths
- Respiratory distress syndrome/hyaline membrane disease; transient tachypnea of the newborn/wet lung; meconium aspiration syndrome; pleural effusion; pneumothorax: congenital lung malformations
- Sepsis; pneumonia (GBS, other infectious organisms)
- Congenital heart disease; persistent pulmonary hypertension of the newborn
- Blood loss/anemia
- Tracheoesophageal fistula
- Congenital diaphragmatic hernia
- Upper airway obstruction
- Inborn errors of metabolism
- Trauma or intracranial bleed
- Drug withdrawal syndromes
- Chest wall deformities
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:
- 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)
- Tracheal deviation, displaced apical beat, thrill may be palpable in the precodium
- Usually not very informative in the newborn (may have dullness to percussion with consolidation, or hyper-resonance with a pneumothorax)
- 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.
- Transillumination of the chest wall is used to quickly detect a pneumothorax
- Arterial blood gas (ABG) or capillary blood gas
- CBC with differential, blood cultures
- Blood glucose
- Other blood work will depend on the differential diagnosis
- Chest x-ray (CXR)
- Echocardiogram/ECG (if indicated)
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.
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.
Written by: Shir Minnes
Edited by: Jeff Bishop