Background Concern exists that living wills are misinterpreted and may result in compromised patient safety.

Aim To determine whether adding code status to a living will improves understanding and treatment decisions.

Methods An Internet survey was conducted of General Surgery and Family, Internal and Emergency Medicine residencies between May and December 2009. The survey posed a fictitious living will with and without additional clarification in the form of code status. An emergent patient care scenario was then presented that included medical history and signs/symptoms. Respondents were asked to assign a code status and choose appropriate intervention. Questions were formatted as dichotomous responses. Correct response rate was based on legal statute. Significance of changes in response due to the addition of either clinical context or code status was assessed by contingency table analysis.

Results 768 faculty and residents at accredited training centres in 34 states responded. At baseline, 22% denoted ‘full code’ as the code status for a typical living will and 36% equated “full care” with a code status DNR. Adding clinical context improved correct responses by 21%. Specifying code status further improved correct interpretation from 28% to 34%. Treatment decisions were either improved 12–17% by adding code status (‘Full Code,’ ‘Hospice Care’) or worsened 22% (‘DNR’).

Discussion Further research is required to ensure safety, understanding, and appropriate care to patients.

Conclusion Misunderstanding of advance directives is a nationwide problem. Addition of code status may help to resolve the problem.