- Describe the microscopic appearance of the lung sections (images
1.2 - 1.4).
Sections show immature lung with alternating areas of atelectasis and alveolar dilatation. Alveolar walls are thick, there is marked vascular congestion, air spaces contain fluid and scattered macrophages, and alveoli are lined by thick pink hyaline membranes. In image 1.4, the jaundice has stained the hyaline membranes yellow.
- What is the material in the alveoli? What other findings are present that are significant in understanding this infant's demise?
Hyaline membranes are made of coagulated protein and fibrin. The low ratio of air space to interstitium is evidence of the lung's immaturity, a significant risk factor for recovery. Another finding indicating immaturity that is not demonstrated in the kodachromes is the presence of immature cartilage around bronchi.
- What is the diagnosis? What are the clinical manifestations of this disease?
Hyaline membrane disease of the newborn. Rapid respirations, inspiratory rib retraction, expiratory grunting, hypoxemia, and cyanosis.
- How might the mother's smoking history have contributed to the outcome? What factors are felt to contribute to the development of this disease?
Smoking during pregnancy is associated with low birth weight infants. Possible contributors to HMD are prematurity, low birth weight, maternal diabetes, intrapartum fetal aspiration, cord asphyxia, birth by Caesarean section, maternal sedation, and neonatal brain injury, with prematurity being by far the most important factor.
- What is the chronic form of this disease called?
Bronchopulmonary dysplasia. It is characterized by interstitial and peribronchial fibrosis, and epithelial hyperplasia and squamous metaplasia of the large airways.
- What decisions must be faced when there is little possibility of a good outcome?
Students may think the most deaths in a hospital are in the trauma unit, or maybe the cancer ward. But it is the NICU. And premature birth is the leading cause of death in the NICU. Should these babies always be 'coded' or is that futile--or worse, cruel? Should parents decide, or neonatologists? These are all issues likely to raise good discussion amongst any group you ask. And the truth is there is enormous variation from one NICU to another. Some doctors want to practice "defensive medicine" and tend to greatly exaggerate the legal threats, and treat every neonate aggressively until death occurs. This is often done from pressure from a hospital's legal counsel, who may be misinterpreting the so-called 'Baby Doe' regulations, whose focus was on Down Syndrome babies. Other NICUs more realistically and more humanely let parents make choices when the chances of a functional baby as the outcome are less than 50-50.
Note that there are two possible outcomes to think about: (1) chance of survival to discharge from the NICU, and (2) chance of survival with little functional impairment and a fairly normal life. Every neonatologist has had patients (babies) who survived with horrible lifelong problems such as blindness, metal retardation, and spasticity of all four limbs. This is probably not what parents wanted when they agreed to an aggressive resuscitation effort. And without even thinking about the parents, have the doctors done something good or terrible when they have an outcome like that? Think of the child and eventual teen and adult who must live like that decades. Or are parents and doctors willing to take a risk that a better outcome is possible, knowing they are likely to deal with a poor outcome?
