The study examined the effects of endotracheal suction with and without saline instillation on neonates with respiratory distress. In a completely counterbalanced factorial-within-subjects design, 2 7 intubated neonates were randomly assigned to two orders of presentation of treatment conditions. Heart rate and blood pressure were continuously recorded throughout both treatment conditions. The ratio of arterial oxygen tension to alveolar oxygen tension was used to assess oxygenation. Results indicated that clinically stable newborns tolerated instillations of 0.25-0.5 ml. The suctioning protocol used In this study minimized changes in infants' heart rates and blood pressures.