Effective intensive care units (ICUs) require a complex choreography of nurse tasks and architectural acoustic design that is only beginning to be understood. Unfortunately, the sound environments of many hospital settings, including ICUs, often fall far short of supporting the underlying mission of hospitals. There is strong and growing evidence that ICU soundscapes impact staff health, stress, and performance. This paper discusses a series of studies conducted by the Healthcare Acoustics Research Team (HART) that focus specifically on the impact of ICU noise on nurse outcomes. In one phase, two ICUs with similar patient acuity but differing architecture were compared via objective acoustic measures and nurse questionnaires. Although overall sound levels in the two wards were essentially identical, nurse perception varied greatly. More detailed analysis revealed that nurse response was correlated with the occurrence rate of peak and maximum sound levels in the units. A follow-up phase looked more closely at the association between healthcare sound environments and specific caregiver tasks such as auditory monitoring of patients. In another phase, results from ICU nurse surveys were compared to other personnel groups with similar distributions of gender, education, and age from non-ICU healthcare settings, offices, and pre-schools. This phase further investigated the relationships between the sound environment and nurse stress symptoms such as auditory or mental fatigue, tension, and irritation. Taken as a whole, these studies provide new insight into the impact of hospital acoustics on nurses and potential steps to improve the sound environment.