This chapter focuses on classic congenital central hypoventilation syndrome (CCHS) cases in which symptoms appear early in life. The principal issues in CCHS are to determine what brain structures are damaged in CCHS to cause the loss of CO2 and O2 sensitivity, disturbances in autonomic function, and other affective and cognitive deficits. Among the processes affected in CCHS appears to be the integrity of multiple neurotransmitter systems. Structural and functional magnetic resonance imaging (MRI) procedures provide a valuable means to assess gray and white matter injury and impaired brain function in the syndrome, and, in the same fashion as numerous other disease processes, the descriptions have the potential to reveal normal mechanisms for serving breathing and autonomic functions. Injury in cognitive and memory regulatory areas has also been revealed. As MRI technology improves, further differentiation of the nature of injury, especially finer discrimination of fiber injury, will be possible.

Capnography can provide important clues concerning the acid-base status of patients. Arterial blood gas analysis is essential to properly evaluate the acid-base status, and diagnose and treat underlying disorders. Acids and bases are constantly formed in the body as by-products of metabolism, and are carefully regulated. Buffering mechanisms include intracellular and extracellular chemical buffers, regulation of CO2 by the respiratory and central nervous systems (CNS), and control of bicarbonate by the kidney. Capillary blood samples can be used, particularly in children, to measure arterial blood gases (ABGs). Loop and thiazide diuretics can incite a metabolic alkalosis, while carbonic anhydrase inhibitors can cause a metabolic acidosis. Overdoses of drugs can produce mixed acid-base disorders, such as the combined metabolic acidosis and respiratory alkalosis from a salicylate overdose. Simple acid-base disorders involve a primary abnormality in either metabolism or respiration that produces a secondary change, or compensatory response, in the other component.