This study's general objective was to evaluate the efficacy of nursing orientation to reduce the anxiety of patients with acute coronary syndrome undergoing bed bath. The specific objectives included: the development and validation of an informative manual concerning bed bath; correlation of physiological variables (systolic and diastolic blood pressure and heart and respiratory rate) with the patients' state anxiety; correlation of antecedent variables (age, gender, cardiovascular risk factor, use of beta blockers, trait anxiety, depression, prior hospitalization, prior experience with bed baths, the patients' preference for a female or male professional to perform the bath, pain, fear, and embarrassment) with the patients' state anxiety.

Patients with acute coronary syndrome present many physiological and psychological changes, especially anxiety, which can be more intense when the patient expects or experiences certain procedures, such as bed bath. The association of anxiety and acute myocardial infarction has shown negative impact on the prognosis of these patients. The anxiety causes activation of the sympathetic nervous system by increasing cardiac contractility, blood pressure, heart rate and oxygen consumption, worsening disease progression. Thus, minimizing the effects of patients' anxiety in the face of various nursing procedures is essential to quality care. The anxiety can be reduced using medications and/or nursing orientation.

This study was conducted in the Coronary Care Units, Brazilian Heart Institute. The study was divided into two phases. The first comprised the development and validation of an informative manual by nurses and patients. The manual was developed by the researchers and then submitted to validation by five nursing professors from the field of nursing fundamentals and five nurses with experience in coronary care units. The Delphi Technique was used to validate the manual in this phase. After validation by nurses, the manual was validated by 35 patients hospitalized in the coronary care unit who experienced bed bath at least once. A score above 4 should be achieved for the manual to be considered comprehensible and validated by patients. The statistical analysis at this phase was performed through the Wilcoxon rank-sum test and percentage of score 5 with its confidence interval. The study's second phase comprised assessment of the efficacy of nursing orientation to reduce the anxiety of patients with acute coronary syndrome undergoing bed baths. The sample population was composed of 120 patients with acute coronary syndrome hospitalized in coronary care units divided into two groups: control group (patients who did not read the informative manual concerning bed bath and received only the unit's routine information) and the intervention group (patients who received nursing orientation and read the informative manual concerning bed bath). The STAI-state was used to assess anxiety. It was applied immediately after informing the patients about the bed bath, immediately after orientation (intervention group) or immediately after the unit's routine information (control group), and immediately after the bath.

Inclusion Criteria:

• Clinical diagnosis of acute coronary syndrome Killip 1
• Patients who were undergoing the bed bath for the first time in the current hospitalization
• Literate and at least 4 years of study
• Patients with age less than 75 years
• Patients who agreed to participate

Exclusion Criteria:

• Patients with vascular diseases or arteriovenous fistulas in the left arm
• Situations that could influence patients' anxiety and / or vital signs (arrhythmias such as ventricular tachycardia, second or third-degree atrioventricular block ; ischemic pain before, during or after bath; patients with Killip 2, 3 and 4; invasive procedures on the day of data collection, such as catheterization and surgery, and use of benzodiazepines and / or anxiolytics
• Situations in which patients were not able to complete the questionnaires (altered level of consciousness, visual impairment and / or patients who could not read and / or write)
• Situations in which the patient requested information about bed bath, previously the beginning of the evaluation.