A clinical study was analyzed on respiratory care of 919 critically ill patients who admitted between 1976 and 1979, which was 4.3% of 16,617 patients in post-operative recovery room of Seoul National University Hospital. 1) The patients who need respiratory cares were annually increased 76 in 1979, 115 in 1977, 289 in 1978 and 439 in 1979, and their overall mortality was 16.8%. 2) Among 439 patients, male were 267(60.8%), and female 172(39.2%) in 1979. 3) The highest age group was 1 to 10 year of age, 142 patients in number(32.4%). 4) The duration of ventilatory assistance was the longest(144.02 hours) for patients of abdominal surgery and 17.5 hours for patients of open heart surgery. 5) Major causes of deaths(84cases) in respiratory care patients of respiratory intensive care units were brain injuries(29 cases) and low cardiac output syndromes(28cases). 6) Types of airway in ventilatory assistance were orotracheal routes(345 cases) and tracheostomy routes(81 cases). 7) Importances of hemodynamic monitorings including Swan-Ganz catheterizations and blood gases and measurements of colloid osmotic pressure for critically ill patients in respiratory care units were literarily discussed.