Post-Operative Delirium & Cardiac Surgery: The Role of Nursing Care

Tuesday, July 12, 2011: 11:10 AM

Priscilla G. Taipale, MSN, RN1
Pamela A. Ratner, PhD, RN, FCAHS2
Paul Galdas, BSc, (Hons), PG, Cert, Ed, PhD, RN3
Carol Jillings, PhD, RN1
(1)School of Nursing, University of British Columbia, Vancouver, BC, Canada
(2)Nursing, University of British Columbia, Vancouver, BC, Canada
(3)School of Nursing and Midwifery, The University of Sheffield, Sheffield, United Kingdom

Learning Objective 1: Understand the complex nature of post-operative delirium affecting cardiac surgery patients, and the role nurses have in delirium assessment, identification and prevention when providing care.

Learning Objective 2: Recognize the responsibility of nurses in providing analgesia and sedation in the intensive care unit that is guided by evidenced based practice and critical thinking.


Post-operative delirium following cardiac surgery is a debilitating and costly adverse event affecting the delivery of nursing care and complicating patient recovery. Uncontrolled pain, and the pro re nata (PRN) administration of sedation and analgesia given in the post-operative period, may be risk factors for delirium. This study examined the risk factors of PRN opioid and benzodiazepine administration to determine whether a relationship exists between incident delirium and nurses’ drug administration practices.


This prospective observational study included 92 male and 32 female patients undergoing cardiac surgery with cardiopulmonary bypass. Patients were assessed for delirium during the first 3 post-operative days with the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) and the Richmond Agitation and Sedation Scale (RASS). Risk factor data, opioid analgesia and benzodiazepine dosages were collected. Chart reviews were conducted retrospectively to determine the sensitivity and specificity of the CAM-ICU tool.


Delirium occurred in 37.7% to 44.3% of the sample, depending on delirium definition. Delirium positive patients had higher relative frequencies of 16 of 18 risk factors studied. Opioid analgesia administration practices (total dosage) had wide variation; no statistically significant relationship with delirium was found (Mdn = 76.8, U = 1697.0, p = .47). Midazolam administration practices (total dosage) also demonstrated wide variation; a statistically significant relationship with post-operative delirium was found (Mdn = 3.0, U = 1251.5, p < .01, χ² = 8.4, df = 3, p < .05).


Nurses in this study provided surprisingly little analgesia; however, only the administration of Midazolam was associated with the development of delirium. This insight into nurses’ PRN decision-making when providing analgesia and sedation to post-operative cardiac surgery patients suggests that standardized delirium assessments, and education regarding analgesia and sedation administration practices may be required to reduce the incidence of post-operative delirium following cardiac surgery.