Definitive diagnosis can only be made through an autopsy, so diagnosis otherwise is really a strong suspicion and based on clinical presentation (along with historical factors, unexpected respiratory distress, or the symptoms described above).
In such cases where pulmonary hypoplasia is suspected, your baby will require intubation and assisted ventilation, with the ventilator set to a very low pressure. Where there is congenital diaphragmatic hernia, the stomach and bowels will need to be decompressed, otherwise ventilation can worsen lung malfunction. The baby will be evaluated for pH and blood gases through an umbilical arterial catheter, and sent for a chest x-ray. Oxygen saturation monitors will be placed on the right hand and left foot to measure pulmonary hypertension.
Other treatments will include administration of inhaled nitric oxide and continued vigorous resuscitation that can last several hours. Finally, surgery may be required in the case of CDH to repair the hernia.
According to www.ucsfhealth.org, the "outcome of infants with P-Hyp is related mainly to lung size and presence of other anomalies." Because of the difficulty of diagnosing P-Hyp clinicalyl, accurate mortality statistics are not available. Prenatal ultrasounds can help predict the outcome of infants with congenital diaphragmatic hernia (Lung:Head Ratio at 22-27 weeks). Severe P-Hyp, due to renal causes of olighydramnios, generally has a poor prognosis for survival. Survivors of P-Hyp often have chronic lung disease. Infants with CDH also have associated problems with feeding, growth and development.
Sources: www.patient.co.uk, www.wrongdiagnosis.com, www.ucsfhealth.org, www.dictionary.com