Ventilatory mechanics and strength: long-term re-examinations and position change

¹ Cardiopulmonary Laboratory and Regional Respiratory Center, Creighton Memorial-St. Joseph's Hospital, Chair of Cardiovascular Research, Department of Medicine, and Department of Physiology and Pharmacology, Creighton University School of Medicine, Omaha, Nebraska

Sixteen comparisons (3 in females, 13 in males) were made of pulmonary function tests in the standing, seated and supine positions. The significant changes were an increase in tidal volume on standing from either the seated or supine positions, but no change on lying (supine) from the seated position; a progressive decrease in the expiratory reserve volume on going from the standing to the seated to the supine positions; an increase in the inspiratory capacity on lying supine from either seated or standing positions, but no significant change on standing from the seated position; and a suggestion of increased turbulence (k₂ term) on passing from the seated to either of the other positions. The other functions tested (minute volume, vital capacity, maximal pressures, elastance, resistance, maximal flows) did not change significantly. The variation and progression of week-to-week changes are described for five paralyzed patients after poliomyelitis and three normal subjects studied over a 2–3 month period. The changes occurring in five normal subjects studied at about 9-month intervals for periods of 9–39 months are also described.