1.8* Project Summary:
There is remarkable variability in clinical practice and a lack of consensus amongst anesthesiologists
providing care for cardiac surgery patients on a number of fronts. Some of these topics include
variation in pulmonary management with utilization of lung protective ventilation strategies,
neuromuscular blockade management, timing of reversal of neuromuscular blockade in the ICU, and
concern for hyperoxia with 100% FiO2 administration. Regarding hemodynamic management, there
are various opinions and strategies for vasopressor and inotrope selection, fluid management,
transfusion thresholds, autologous blood removal, venous anterograde and retrograde arterial priming
of the bypass circuit, threshold of adequate pump flow while on cardiopulmonary bypass, and
placement of monitors such as a pulmonary artery catheter. Practice variation also exists amongst
neurologic modulation for choice of induction agents including the role of benzodiazepines, use of BIS
monitors, and neuroprotection strategies.(1–3) Describing cardiac anesthesiologist’s choices of
induction agents, primarily the use or lack of use of benzodiazepines, is a topic with implications for
hemodynamic stability, and in neurocognitive recovery after cardiac surgery.
Conflicting evidence exists regarding the role of benzodiazepines in cardiac surgery. Some studies
focusing on administration of benzodiazepines in the ICU have shown that benzodiazepines are
associated with an increased risk of delirium or disrupted neurocognitive recovery surgery,(1–7) but
some anesthesiologists specifically utilize benzodiazepines for their amnestic properties due to a
higher than average rate of intraoperative awareness in the cardiac surgery population since there is
little data on the impact of intraoperative use of benzodiazepines.(1,8–11) A survey of cardiac
anesthesiologists in Canada found that 89 percent of respondents did routinely use benzodiazepines,
yet, a majority believed most cardiac anesthetics could safely be performed without benzodiazepines.
(1) Gaps exist in the current literature in determining the impact of benzodiazepine use on
postoperative outcomes.(1,8) As emerging evidence suggests that postoperative delirium may be
associated with increased morbidity, mortality, prolonged ventilation, and increased length of stay,(4–
6,12–16) it is important to determine strategies to prevent delirium in the cardiac surgery population.
Although work has been done in the intensive care unit regarding the impact of benzodiazepine use,
and practice patterns in Canada have been identified via survey,(1) little is known about practice
patterns in the United States.
In this descriptive study, we plan to investigate practice patterns regarding benzodiazepine use
including incidence of use, total dosage, and context of benzodiazepine use during the perioperative
period for cardiac surgical cases with data obtained from the electronic medical records from a variety
of institutions across the United States. We aim to provide descriptive data from the electronic medical
record regarding practice variation of benzodiazepine administration to better frame the discussion
surrounding benzodiazepine use and guide future studies. As more research is done regarding the
impact of intraoperative benzodiazepines on delirium, morbidity, and mortality, with randomized clinical
trials, quantifying the use of benzodiazepines in the United States will contribute to any extrapolation
of these findings and potential impact on current practices.
1. Spence J, Belley-Côté E, Devereaux PJ, Whitlock R, Um K, McClure G, Lamy A, LeManach Y,
Connolly S, Syed S: Benzodiazepine administration during adult cardiac surgery: a survey of current
practice among Canadian anesthesiologists working in academic centres. Can J Anaesth 2018;
65:263–71
2. Kassie GM, Nguyen TA, Kalisch Ellett LM, Pratt NL, Roughead EE: Preoperative medication use
and postoperative delirium: a systematic review. BMC Geriatr 2017; 17:298
3. Maldonado JR, Wysong A, Starre PJA van der, Block T, Miller C, Reitz BA: Dexmedetomidine and
the reduction of postoperative delirium after cardiac surgery. Psychosomatics 2009; 50:206–17
4. Saczynski JS, Marcantonio ER, Quach L, Fong TG, Gross A, Inouye SK, Jones RN: Cognitive
trajectories after postoperative delirium. N Engl J Med 2012; 367:30–9
5. Riker RR, Shehabi Y, Bokesch PM, Ceraso D, Wisemandle W, Koura F, Whitten P, Margolis BD,
Byrne DW, Ely EW, Rocha MG, SEDCOM (Safety and Efficacy of Dexmedetomidine Compared With
Midazolam) Study Group: Dexmedetomidine vs midazolam for sedation of critically ill patients: a
randomized trial. JAMA 2009; 301:489–99
6. Pandharipande PP, Pun BT, Herr DL, Maze M, Girard TD, Miller RR, Shintani AK, Thompson JL,
Jackson JC, Deppen SA, Stiles RA, Dittus RS, Bernard GR, Ely EW: Effect of sedation with
dexmedetomidine vs lorazepam on acute brain dysfunction in mechanically ventilated patients: the
MENDS randomized controlled trial. JAMA 2007; 298:2644–53
7. Pandharipande P, Shintani A, Peterson J, Pun BT, Wilkinson GR, Dittus RS, Bernard GR, Ely EW:
Lorazepam is an independent risk factor for transitioning to delirium in intensive care unit patients.
Anesthesiology 2006; 104:21–6
8. Spence J, Belley-Côté E, Lee SF, Bangdiwala S, Whitlock R, LeManach Y, Syed S, Lamy A,
Jacobsohn E, MacIsaac S, Devereaux PJ, Connolly S: The role of randomized cluster crossover trials
for comparative effectiveness testing in anesthesia: design of the Benzodiazepine-Free Cardiac
Anesthesia for Reduction in Postoperative Delirium (B-Free) trial. Can J Anaesth 2018; 65:813–21
9. American Society of Anesthesiologists Task Force on Intraoperative Awareness: Practice advisory
for intraoperative awareness and brain function monitoring: a report by the american society of
anesthesiologists task force on intraoperative awareness. Anesthesiology 2006; 104:847–64
10. Sebel PS, Bowdle TA, Ghoneim MM, Rampil IJ, Padilla RE, Gan TJ, Domino KB: The incidence of
awareness during anesthesia: a multicenter United States study. Anesth Analg 2004; 99:833–9, table
of contents
11. Orser BA, Mazer CD, Baker AJ: Awareness during anesthesia. CMAJ 2008; 178:185–8
12. Sanson G, Khlopenyuk Y, Milocco S, Sartori M, Dreas L, Fabiani A: Delirium after cardiac surgery.
Incidence, phenotypes, predisposing and precipitating risk factors, and effects. Heart Lung 2018;
47:408–17
13. Samuel M: Postoperative delirium in older adults: best practice statement from the American
Geriatrics Society. JMAGSEP 2015; 220:136–49
14. Koster S, Hensens AG, Palen J van der: The long-term cognitive and functional outcomes of
postoperative delirium after cardiac surgery. Ann Thorac Surg 2009; 87:1469–74
15. Leslie DL, Marcantonio ER, Zhang Y, Leo-Summers L, Inouye SK: One-year health care costs
associated with delirium in the elderly population. Arch Intern Med 2008; 168:27–32
16. Stransky M, Schmidt C, Ganslmeier P, Grossmann E, Haneya A, Moritz S, Raffer M, Schmid C,
Graf BM, Trabold B: Hypoactive delirium after cardiac surgery as an independent risk factor for
prolonged mechanical ventilation. J Cardiothorac Vasc Anesth 2011; 25:968–74
1.9* Select the appropriate IRB:
IRBMED