It is Time to Perform Benzodiazepine-free Cardiac Surgery
Pratik P. Pandharipande, M.D., MSCI
Professor of Anesthesiology, Critical Care
Vanderbilt University Medical Center
Email: pratik.pandharipande@vanderbilt.edu
Delirium is an acute disturbance of consciousness accompanied by inattention,
disorganized thinking, and perceptual disturbances that fluctuates over a short period of
time. The incidence of delirium following coronary artery bypass grafting (CABG) and
other cardiac surgeries varies from 20 to 40%, and is associated with longer hospital
stays, readmissions, poor cognitive and functional outcomes, and mortality.
Delirium is thought to be multifactorial, and contributing sources can be
summarized as patient related factors (e.g. age, previous dementia, etc.) or iatrogenic risk
factors (e.g. psychoactive medications, hypoxemia, etc.) Of these risk factors,
benzodiazepines and opiates are potentially modifiable and have been implicated in the
development of delirium in a number of ICU and non-ICU patients.
Numerous studies have examined risk factors and predictors of delirium and
cognitive dysfunction following cardiac surgery. Increasing age, cerebrovascular disease
(e.g. prior stroke), peripheral vascular disease, smoking, atrial fibrillation, renal
dysfunction, diabetes mellitus, and heart failure (ejection fraction < 40%) are patient
characteristics found to be associated with increased risk of postoperative delirium.
Perioperative factors that led to increased likelihood of delirium included preoperative
cardiogenic shock, emergent operation, operative time > 3 hours, longer cardiopulmonary
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bypass (CPB) time, balloon pump support, hypothermia, hypoxemia, and high
perioperative transfusion requirements. More recently, in a prospective cohort of patients
admitted to the CVICU after cardiac surgery, benzodiazepines received in the immediate
perioperative period conferred a 3-fold increase in the risk of developing delirium.
Benzodiazepines and other immobilization devices were risk factors for further daily
development of delirium. Given emergence of strong data implicating benzodiazepines in
delirium in non-cardiac and now cardiac surgical patients, it is imperative for us to
consider this risk factor since it may be the one that we can control and can therefore
potentially modify.
The objectives of presentation will be to inform the audience of the deleterious
effects of delirium, to demonstrate that benzodiazepines are modifiable risk factors and to
share data where non-benzodiazepine sedation paradigms have been associated with
better outcomes in critically ill patients.
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