William C. Young

Negative pressure assisted ventilation in infants with hyaline membrane disease

Since October, 1961, 80 infants thought to have potentially fatal hyaline membrane disease have received assisted ventilation with a negative pressure tank-type respirator as part of their intensive care management. Thirty-one (39 per cent) survived. It is thought that this form of therapy can be potentially life saving in severely ill infants whose birth weight is more than 1,500 grams and whose arterial PO 2 value while breathing 100 per cent oxygen is less than 40 mm. Hg.

THE MANAGEMENT OF RESPIRATORY FAILURE IN THE IDIOPATHIC RESPIRATORY DISTRESS SYNDROME OF PREMATURITY

The management of respiratory failure associated with idiopathic respiratory distress syndrome of prematurity, or, as we prefer to call it, clinical hyaline membrane disease, is an important facet in the therapy of this condition. However, it is the final stage of a program of management, and, in most instances, can be avoided by early attention to other aspects of the syndrome which pressage its occurrence. Respiratory failure usually follows a period of marked respiratory effort after birth, associated with decreasing lung compliance, progressive atelectasis, vascular congestion, and eventual physical exhaustion. Severe metabolic changes usually accompany this progressive deterioration with lactic acidemia and hyperkalemia often contributing to the clinical picture (TABLE 1 ) . Severe anoxemia, despite oxygen therapy, a falling arterial pH, and a rising PaC02, reflect the failure of both respiration and circulation to meet the infant’s needs. If, despite attempts at oxygenation and buffering of pH, an infant with severe hyaline membrane disease shows progressive anoxemia associated with decreasing respiratory effort, respiratory assistance is indicated. These events usually occur gradually over a period of several hours and may not develop until the infant has exhausted himself at 24 to 48 hours after birth. The premonitory signs are usually recognizable, although sudden respiratory arrest can occur without warning in a previously satisfactory baby. This may be due to a cardiac emergency such as an arrhythmia or standstill, to mucous plugging in the airway, to acute and overwhelming pulmonary edema or hemorrhage, or to a seizure. The baby whose course is gradually and inexorably downhill toward respiratory failure is much more common. One of the first warnings is the development of very irregular respiration followed by a gradual but steady decrease in respiratory rate and effort without other signs of improvement in a baby previously making maximum efforts to breathe. When the respiratory rate drops by 20 to 30/min. over a course of 30 to 60 minutes, especially if accompanied by deepening cyanosis, some type of ventilatory aid will be needed shortly. The cyanosis is usually ashy gray at this point due to extreme peripheral vasoconstriction, and the pH can be predictably estimated at a dangerously low level and dropping fast. Bradycardia may develop as deterioration progresses and conduction defects appear on the electrocardiogram. The infant ceases to breathe except for convulsive gasps. Ashy cyanosis becomes extreme and the baby dies if unassisted. Two types of ventilatory assistance have been used by us, each with advantages in certain circumstances and they can be combined on some occasions with good effect. The first and most widely available type of ventilatory assistance for infants is intermittent positive pressure insufflation of the lungs. This cannot be carried out for any prolonged period of time with a mask and requires tracheal intubation or tracheostomy. We have used a pressure control rather than a volume control system, although both are available. A maximum of 30 mm. Hg. or 40 cm. of water is the limit of pressure used and lower pressures are much preferred but not

Observations on skin resistance to electricity and sweat chloride content. A preliminary report.

Summary Skin resistance to electrical current andsweat chloride values have been reported in 4 groups of children; white children in a control group; Negro children in a control group; white children with cystic fibrosis; and white children with central nervous system disease. The various groups studied could be distinguished both with respect to sweat chloride and skin resistance measurements. Further studies are under way to determine if the test can be developed to be useful as a screening and diagnostic procedure.

From Interior Algebras to Unital ℓ-Groups: A Unifying Treatment of Modal Residuated Lattices

Much work has been done on specific instances of residuated lattices with modal operators (either nuclei or conuclei). In this paper, we develop a general framework that subsumes three important classes of modal residuated lattices: interior algebras, Abelian ℓ-groups with conuclei, and negative cones of ℓ-groups with nuclei. We then use this framework to obtain results about these three cases simultaneously. In particular, we show that a categorical equivalence exists in each of these cases. The approach used here emphasizes the role played by reducts in the proofs of these categorical equivalences. Lastly, we develop a connection between translations of logics and images of modal operators.