Thomas D. Downs

A Method for Ventilatory Measurements in Subjects 1 Month-5 Years of Age: Normal Results and Observations in Disease

Extract: Using the total body plethysmograph, a method for the measurement of lung volume and airway resistance was developed for infants and young children of 1 month-5 years of age. The subjects were studied in a supine position using a reproducible method of sedation. The procedure providing the most consistent results involved use of a Rendell-Baker mask directly controlled by the operator while the subjects were breathing through the nose. Availability of an oscilloscope permitted immediate detection of pressure leaks, artifacts, and abnormal patterns during each determination and minimized potential errors during the study of each subject. Care was required to avoid pressure on the tip of the nose because an abnormally high airway resistance resulted.The logarithmic relation of thoracic gas volume (TGV) at functional residual capacity (FRC) to body length for 52 normal subjects compared well with results obtained on newborn infants and with those obtained on older subjects. The equation was: TGV at FRC, litters = 1.57 × 10-5 × length, cm2.238 (correlation coefficient = 0.948). The logarithmic relation of airway conductance to TGV was: conductance, liters/sec/cm H2O = 0.1431 TGV, liters0.6441 (correlation coefficient = 0.835). Comparison with older subjects was limited by the difference in airflow rates at which the airway conductance was determined (0.06-0.28 liters/sec versus about 0.5 liters/sec for adults) and by the use of sedation and nasal breathing in this study; adults are studied a wake and during mouth breathing. Comparison of our conductance values with those obtained on unsedated newborns suggests that either sedation alters the airway resistance or that some change occurs in the airway size-lung volume relation during the first weeks of life.Examples of the application of this method to patients with asthmatic bronchitis and cystic fibrosis of the pancreas are provided.Speculation: It is possible that an airflow-lung voliume-airway resistance relation exists throughout life; however, the results presented in this study, combined with those previously presented on newborns for airway resistance, suggest that a change may occur in the relation of the size of the airways to lung volume during early infancy, or that sedation alters airway resistance. Development of this and other methodology should permit more adequate studies of the early changes in pulmonary physiology associated with growth and the acute and chronic pulmonary conditions seen during the first 5 years of life.

The normal adolescent electrocardiogram.

Abstract Criteria for the interpretation of the electrocardiogram of the adolescent are presented in tabular form. Three major areas of difference were noted between the electrocardiograms of adolescents and other individuals. These were: (1) The summation of the amplitudes of SV 2 and RV 5 was markedly greater in the adolescent than in adult studies; (2) J-point elevation (Leads aV F , V 5 , and V 6 ) was a frequent finding (25 per cent) in adolescents; (3) the rotation of the QRS loop in the frontal plane was clockwise in the majority (62 per cent) of adolescents.

Longitudinal Study of the Standard Electrocardiogram in the Healthy Premature Infant During the First Year of Life

Abstract Data from serial electrocardiograms obtained from healthy premature infants aged 24 hours to 1 year are presented. Comparison is made mainly with Zieglers data on healthy full-term infants. Although there were many similarities, important differences were noted. All wave durations in the electrocardiograms of healthy premature infants were shorter than those of healthy full-term infants. The P and QRS vectors were directed more to the left and posteriorly in premature infants than in full-term infants, and there was less right ventricular dominance at birth in premature infants than in full-term infants.

Chronic-disease Classification in Evaluation of Medical Care Programs

For ideal classification of chronic disease in large populations, identification of the presence or absence of every chronic disease in every person would be desirable, as would knowledge of specific causes and pathogenesis, means to define cause, measure severity, and identify important milestones. The authors have approached the problems by analyzing advantages and disadvantages of certain aids to classification of chronic disease, namely, categorical disease classification, disability classification, and multiphasic screening. They describe a modified approach to classification, developed in conjunction with studies of the chronically ill and aged, which consists of establishing for each person a profile that includes principal diagnosis, disease status defined by chronic disease screening, and disability status based on comparable and systematic evaluation. A set of classes which combines the advantages of each of the separate approaches to chronic disease description is synthesized. An illustration of the use of this approach in describing the chronic disease status of one group is presented. The approach can be adapted to other populations and other purposes, and the authors suggest that it should be of particular use in large-scale population studies.

Results of long-term home nursing: The influence of disability☆

Abstract An experimental, controlled study of the effect of home nursing on patients discharged from a chronic disease rehabilitation hospital has demonstrated that, over a 2-yr period, mildly or moderately disabled patients benefit in terms of physical and mental function and by avoiding admission to nursing homes. Severely disabled patients, on the other hand, do not show results, but are influenced to make greater use of other health services.