13,242views
00:00 / 00:00
of complete
Laboratory value | Result |
Blood Gases, Serum | |
pH | 7.23 |
PCO2 | 55 mmHg |
PO2 | 30 mmHg |
Two people are admitted to the emergency department.
Mike, a 55-year-old man, presents with shortness of breath, high fever, and cough.
A chest x-ray was ordered and it showed a right lower lobe infiltrate, which is suggestive of pneumonia.
He was then started on IV antibiotics but the following day Mike became hypoxic and hypotensive.
Because his hypotension didn’t improve despite intubation, IV fluids, and vasopressors, he is diagnosed with septic shock.
Next, a repeat x-ray detected newly-developed bilateral alveolar opacities, heart echography ruled out heart failure, and arterial blood gas analysis revealed a PF ratio of 109 milligrams Mercury.
Then there was Dona, an infant delivered by cesarean section at 36 weeks’ gestational age, with an Apgar score of 9 at birth.
A few hours after delivery, she develops tachypnea, chest wall retractions with nasal flaring, and tachycardia.
Aside from increased work of breathing, her physical examination findings are normal.
A chest x-ray was ordered and it showed diffuse reticulogranular ground glass appearance with air bronchograms.
Now, both people are in respiratory distress.
But first, a bit of physiology.
Normally, when you breathe in, the air reaches the alveoli, which are made up of two types of pneumocytes.
First, type I pneumocytes are thin, and have a large surface area that that facilitate gas exchange.
More important for the exams are the type II pneumocytes, which are smaller, thicker and have the ability to proliferate in response to lung injury.
They are in charge of making a fluid called surfactant which contains various phospholipids.
This lets it act like droplets of oil that coats the inside of the alveoli, decreasing surface tension, so if it’s missing, the alveoli will collapse.
Respiratory distress syndrome (RDS) is a respiratory condition in which the alveoli collapse due to the deficiency of the surface-active substance called surfactant. Collapsed alveoli make it difficult to breathe and get enough oxygen. Acute respiratory distress syndrome happens when inflammation causes diffuse alveolar injury and pulmonary edema. This edema can wash away the surfactant coating the alveoli to the point where it causes the alveoli to collapse. There is also neonatal respiratory distress syndrome, which mostly affects premature infants, whose lungs are not fully developed and lack enough surfactant.
Symptoms of respiratory distress syndrome include rapid breathing, grunting, and flaring of the nostrils while breathing, as well as cyanosis (bluish color of the skin) and difficulty feeding. All forms of respiratory distress can lead to respiratory failure and death if not treated promptly. Treatment includes providing respiratory support, and administering surfactants, especially in neonatal respiratory syndrome. The use of corticosteroids before delivery may also be considered to improve lung function in some cases.
Copyright © 2024 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Cookies are used by this site.
USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.