Introduction: Controversy remains about the impact of 12-h shift patterns on staff satisfaction and health and on patient outcomes. Consequently, the objective of the study was to investigate the effect on nurses and patients of 8-h rostering compared with 12-h rostering.

Methods: We conducted a two-phase survey. Intensive care nurses completed a purposefully designed 49-item questionnaire, which included open- and closed-ended questions. Phase 1 was conducted during 2015, while the 8-h shift pattern was in place. Data for phase 2 were collected in 2017, approximately 6 months after the trial of 12-h shifts began. We extracted data from the hospital's adverse event register to compare patient outcomes between the two phases.

Results: A total of 152/193 (78.8%) surveys were returned in phase 1. In phase 2, the response rate was 114/188 (60.6%). The proportion of nurses satisfied with the roster increased 3-fold after the introduction of 12-h shifts; risk ratios 3.36 (95% confidence intervals 2.62 to 4.28). Communication with all levels of senior staff improved, and the number of hours of professional development leave increased with the 12-h roster phase 1, 358 h versus 538 h in phase 2 (p = <0.0001). Most respondents believed that 12-h shifts would be beneficial for their health, and this belief was validated by official leave records; there was a reduction of 69 days for sick leave and 216 days for family leave. Adverse outcomes for patients were similar in the two periods.

Conclusion: Twelve-hour shifts are popular with ICU nurses, days lost to sick and family leave are reduced, and patient outcomes are not compromised.