Based on a revision of Donabedian’s classic structure, process, and outcome conceptual framework, this study examined the relationship between resource use (length of stay) and outcome (transfer status) in two respiratory intensive care units (ICUs). Medical records of respiratory ICU patients (N = 194) from a medical center in northern Taiwan were reviewed. Data collection focused on patient demographic profile (age, gender, and medical diagnosis), Acute Physiology and Chronic Health Evaluation (APACHE) score, nursing diagnoses, ICU length of stay, and transfer status. The results indicate that patients with lower APACHE scores and more nursing diagnoses had a longer ICU length of stay. In addition, both the number of nursing diagnoses and APACHE scores significantly explained the variance in the length of stay. Nonetheless, a higher APACHE score was correlated with a poor transfer status. These findings indicate that, in addition to the traditional indicators, nursing diagnoses may be a vital variable in predicting ICU length of stay. The results also imply that patients with lower APACHE scores are in better physical condition and are therefore institutionalized longer in ICUs.