Dexmedetomidine and Delirium in Patients After Cardiac Surgery

Impact of Dexmedetomidine on the Incidence of Postoperative Delirium in Patients After Cardiac Surgery: a Randomized, Double-blinded, and Placebo-controlled Clinical Trial

Postoperative delirium (POD) is a frequently occurring complication after cardiac surgery. Its occurrence is associated with worse outcomes of patients, including increased morbidity, prolonged hospital stay, increased medical cost, and higher mortality. It is also associated with long-term cognitive decline and decreased quality of life. However, until recently, pharmacological interventions that can effectively prevent its occurrence are still limited. The purpose of this study is to investigate whether perioperative dexmedetomidine use can decrease the incidence of postoperative delirium in patients undergoing cardiac surgery.

Delirium is a state of global cerebral dysfunction manifested by acute disturbance of consciousness, attention, cognition and perception. It develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day. The reported incidences of delirium after cardiac surgery varied from 21% to 47%. The occurrence of postoperative delirium has significant harmful effects on patients' outcomes, including increased morbidity, prolonged hospital stay, increased medical cost, and higher mortality. Its occurrence is also associated with long-term cognitive decline and decreased quality of life. The exact pathogenesis that lead to the occurrence of POD are still unclear, and possibly involves mechanisms such as inflammation, pain and sleep deprivation after surgery. Furthermore, it has been shown that anesthesia management might also have exerted some effects. Studies found that avoidance of unnecessary deep anesthesia (under the guidance of Bispectral Index monitoring) decreases the incidence of POD. Theoretically, measures that decreases the requirement of anesthetics while maintaining adequate depth of anesthesia and those that alleviates inflammation and improves postoperative analgesia as well as sleep quality will decrease the incidence of POD. Dexmedetomidine is a highly selective alpha-2 adrenoreceptor agonists that provides anxiolysis, sedation and modest analgesia with minimal respiratory depression. Studies showed that, when used as an adjunctive anesthetics, dexmedetomidine significantly decreases the requirement of opioid analgesics and other sedatives during anesthesia. A recent study of our group found that continuous infusion of low-dose dexmedetomidine (0.2 ug/kg/h) during the first night after surgery significantly improved subjective sleep quality. Two randomized controlled trials found that, when compared with traditional sedatives (midazolam and propofol) and analgesics (such as morphine), use of dexmedetomidine in patients after cardiac surgery is associated with decreased risk of delirium. However, questions still exist as to whether dexmedetomidine prevent delirium or just does not increase its occurrence since traditional sedatives/analgesics themselves increases the risk of delirium. Furthermore, animal experiments showed that dexmedetomidine inhibits the degree of inflammation induced by endotoxins. The investigators hypothesize that use of dexmedetomidine as an adjunctive agent during the perioperative period can decrease the incidence of postoperative delirium in patients undergoing cardiac surgery, possibly by decreasing the requirement of anesthetics during surgery, by ameliorating analgesia as well as sleep quality after surgery, and by alleviating the degree of perioperative inflammatory response.

The intervention drug (dexmedetomidine hydrochloride for injection) will be administered during a period from before anesthesia induction until the end of mechanical ventilation after surgery.

The placebo drug (normal saline, i.e., 0.9% sodium chloride for injection) will be administered in the same way and rate for a same duration as that in the Dex group.

Before anesthesia, dexmedetomidine hydrochloride for injection (200 ug/2 ml) will be diluted with normal saline to 50 ml (final dexmedetomidine concentration 4 ug/ml). Before the induction of anesthesia, a loading dose will be administered by intravenous infusion at a rate of [0.9*kg] ml/h for 10 minutes (i.e., dexmedetomidine 0.6 μg/kg in 10 minutes), followed by continuous infusion at a rate of [0.1*kg] ml/h (i.e., dexmedetomidine at a rate of 0.4 μg /kg/h) until the end of surgery. At the end of surgery, the infusion rate will be decreased to [0.025*kg] ml/h (i.e., dexmedetomidine at a rate of 0.1 ug/kg/h) and continued until the end of mechanical ventilation after surgery.

Before anesthesia, 0.9% sodium chloride for injection 50 ml will be prepared. Before the induction of anesthesia, a loading dose will be administered by intravenous infusion at a rate of [0.9*kg] ml/h for 10 minutes, followed by continuous infusion at a rate of [0.1*kg] ml/h until the end of surgery. At the end of surgery, the infusion rate will be decreased to [0.025*kg] ml/h and continued until the end of mechanical ventilation after surgery.

Delirium was assessed with the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) twice daily during the first five days after surgery.

Cognitive function was assessed with the Mini Mental State Examination (MMSE) at baseline (the day before surgery) and on the sixth day after surgery, and with modified telephone interview for cognitive status (m-TICS) on the 30th day after surgery. The introduction of MMSE scale has been explained in the baseline part in the result section. The Telephone Interview for Cognitive Status-modified scale(m-TICS) is one of the most popular telephone interview-based screening instruments for mild cognitive impairment and dementia. It consists 11 items including wordlist memory, orientation, attention, repetition, conceptual knowledge and nonverbal praxis, which score ranges from 0 to 48, with higher scores indicating better cognitive function

Non-delirium complications was defined as any conditions other than delirium that occurred during the first 30 days after surgery and required therapeutic intervention.Complications listed here were not considered adverse events in this study.

Pain intensity was assessed daily at 8 am during the first five days after surgery with the Numeric Rating Scale (NRS, 0 = no pain, 10 = the worst possible pain).

Subjective sleep quality was assessed daily at 8 am during the first five days after surgery with the Numeric Rating Scale (NRS, 0 = best sleep, 10 = the worst possible sleep).

Inclusion Criteria: Patients of 60 years or older who are planning to receive cardiac surgery (CABG and/or valve replacement surgery) Exclusion Criteria: Patients will be excluded if they meet any of the following criteria: Refuse to participate; Preoperative history of schizophrenia, epilepsia, Parkinson syndrome, or severe dementia; Inability to communicate in the preoperative period because of severe visual/auditory dysfunction or language barrier; History of brain injury or neurosurgery; Preoperative sick sinus syndrome, severe bradycardia (HR < 50 bpm), second-degree or above atrioventricular block without pacemaker; Severe hepatic dysfunction (Child-Pugh class C); Severe renal dysfunction (requirement of renal replacement therapy); Other conditions that are considered unsuitable for participation.

Guenther U, Radtke FM. Delirium in the postanaesthesia period. Curr Opin Anaesthesiol. 2011 Dec;24(6):670-5. doi: 10.1097/ACO.0b013e32834c7b44.

Morandi A, Pandharipande PP, Jackson JC, Bellelli G, Trabucchi M, Ely EW. Understanding terminology of delirium and long-term cognitive impairment in critically ill patients. Best Pract Res Clin Anaesthesiol. 2012 Sep;26(3):267-76. doi: 10.1016/j.bpa.2012.08.001.

Groen JA, Banayan D, Gupta S, Xu S, Bhalerao S. Treatment of delirium following cardiac surgery. J Card Surg. 2012 Sep;27(5):589-93. doi: 10.1111/j.1540-8191.2012.01508.x.

Ely EW, Gautam S, Margolin R, Francis J, May L, Speroff T, Truman B, Dittus R, Bernard R, Inouye SK. The impact of delirium in the intensive care unit on hospital length of stay. Intensive Care Med. 2001 Dec;27(12):1892-900. doi: 10.1007/s00134-001-1132-2. Epub 2001 Nov 8.

Ouimet S, Kavanagh BP, Gottfried SB, Skrobik Y. Incidence, risk factors and consequences of ICU delirium. Intensive Care Med. 2007 Jan;33(1):66-73. doi: 10.1007/s00134-006-0399-8. Epub 2006 Nov 11.

Thomason JW, Shintani A, Peterson JF, Pun BT, Jackson JC, Ely EW. Intensive care unit delirium is an independent predictor of longer hospital stay: a prospective analysis of 261 non-ventilated patients. Crit Care. 2005 Aug;9(4):R375-81. doi: 10.1186/cc3729. Epub 2005 Jun 1.

Milbrandt EB, Deppen S, Harrison PL, Shintani AK, Speroff T, Stiles RA, Truman B, Bernard GR, Dittus RS, Ely EW. Costs associated with delirium in mechanically ventilated patients. Crit Care Med. 2004 Apr;32(4):955-62. doi: 10.1097/01.ccm.0000119429.16055.92.

Hopkins RO, Jackson JC. Short- and long-term cognitive outcomes in intensive care unit survivors. Clin Chest Med. 2009 Mar;30(1):143-53, ix. doi: 10.1016/j.ccm.2008.11.001.

Jackson JC, Gordon SM, Hart RP, Hopkins RO, Ely EW. The association between delirium and cognitive decline: a review of the empirical literature. Neuropsychol Rev. 2004 Jun;14(2):87-98. doi: 10.1023/b:nerv.0000028080.39602.17.

MacLullich AM, Beaglehole A, Hall RJ, Meagher DJ. Delirium and long-term cognitive impairment. Int Rev Psychiatry. 2009 Feb;21(1):30-42. doi: 10.1080/09540260802675031.

Pisani MA, Kong SY, Kasl SV, Murphy TE, Araujo KL, Van Ness PH. Days of delirium are associated with 1-year mortality in an older intensive care unit population. Am J Respir Crit Care Med. 2009 Dec 1;180(11):1092-7. doi: 10.1164/rccm.200904-0537OC. Epub 2009 Sep 10.

Lin SM, Liu CY, Wang CH, Lin HC, Huang CD, Huang PY, Fang YF, Shieh MH, Kuo HP. The impact of delirium on the survival of mechanically ventilated patients. Crit Care Med. 2004 Nov;32(11):2254-9. doi: 10.1097/01.ccm.0000145587.16421.bb.

Witlox J, Eurelings LS, de Jonghe JF, Kalisvaart KJ, Eikelenboom P, van Gool WA. Delirium in elderly patients and the risk of postdischarge mortality, institutionalization, and dementia: a meta-analysis. JAMA. 2010 Jul 28;304(4):443-51. doi: 10.1001/jama.2010.1013.

Krenk L, Rasmussen LS. Postoperative delirium and postoperative cognitive dysfunction in the elderly - what are the differences? Minerva Anestesiol. 2011 Jul;77(7):742-9.

Goto T, Maekawa K. Cerebral dysfunction after coronary artery bypass surgery. J Anesth. 2014 Apr;28(2):242-8. doi: 10.1007/s00540-013-1699-0. Epub 2013 Aug 24.

Steinmetz J, Christensen KB, Lund T, Lohse N, Rasmussen LS; ISPOCD Group. Long-term consequences of postoperative cognitive dysfunction. Anesthesiology. 2009 Mar;110(3):548-55. doi: 10.1097/ALN.0b013e318195b569.

Culley DJ, Baxter M, Yukhananov R, Crosby G. The memory effects of general anesthesia persist for weeks in young and aged rats. Anesth Analg. 2003 Apr;96(4):1004-1009. doi: 10.1213/01.ANE.0000052712.67573.12.

Culley DJ, Baxter MG, Yukhananov R, Crosby G. Long-term impairment of acquisition of a spatial memory task following isoflurane-nitrous oxide anesthesia in rats. Anesthesiology. 2004 Feb;100(2):309-14. doi: 10.1097/00000542-200402000-00020.

Bianchi SL, Tran T, Liu C, Lin S, Li Y, Keller JM, Eckenhoff RG, Eckenhoff MF. Brain and behavior changes in 12-month-old Tg2576 and nontransgenic mice exposed to anesthetics. Neurobiol Aging. 2008 Jul;29(7):1002-10. doi: 10.1016/j.neurobiolaging.2007.02.009. Epub 2007 Mar 7.

Wan Y, Xu J, Ma D, Zeng Y, Cibelli M, Maze M. Postoperative impairment of cognitive function in rats: a possible role for cytokine-mediated inflammation in the hippocampus. Anesthesiology. 2007 Mar;106(3):436-43. doi: 10.1097/00000542-200703000-00007.

Baranov D, Bickler PE, Crosby GJ, Culley DJ, Eckenhoff MF, Eckenhoff RG, Hogan KJ, Jevtovic-Todorovic V, Palotas A, Perouansky M, Planel E, Silverstein JH, Wei H, Whittington RA, Xie Z, Zuo Z; First International Workshop on Anesthetics and Alzheimer's Disease. Consensus statement: First International Workshop on Anesthetics and Alzheimer's disease. Anesth Analg. 2009 May;108(5):1627-30. doi: 10.1213/ane.0b013e318199dc72.

Tang J, Eckenhoff MF, Eckenhoff RG. Anesthesia and the old brain. Anesth Analg. 2010 Feb 1;110(2):421-6. doi: 10.1213/ANE.0b013e3181b80939. Epub 2009 Oct 9.

Chan MT, Cheng BC, Lee TM, Gin T; CODA Trial Group. BIS-guided anesthesia decreases postoperative delirium and cognitive decline. J Neurosurg Anesthesiol. 2013 Jan;25(1):33-42. doi: 10.1097/ANA.0b013e3182712fba.

Burkhart CS, Dell-Kuster S, Gamberini M, Moeckli A, Grapow M, Filipovic M, Seeberger MD, Monsch AU, Strebel SP, Steiner LA. Modifiable and nonmodifiable risk factors for postoperative delirium after cardiac surgery with cardiopulmonary bypass. J Cardiothorac Vasc Anesth. 2010 Aug;24(4):555-9. doi: 10.1053/j.jvca.2010.01.003. Epub 2010 Mar 15.

Abdel-Meguid ME. Dexmedetomidine as anesthetic adjunct for fast tracking and pain control in off-pump coronary artery bypass. Saudi J Anaesth. 2013 Jan;7(1):6-8. doi: 10.4103/1658-354X.109557.

Gerresheim G, Schwemmer U. [Dexmedetomidine]. Anaesthesist. 2013 Aug;62(8):661-74. doi: 10.1007/s00101-013-2206-6. German.

Jalonen J, Hynynen M, Kuitunen A, Heikkila H, Perttila J, Salmenpera M, Valtonen M, Aantaa R, Kallio A. Dexmedetomidine as an anesthetic adjunct in coronary artery bypass grafting. Anesthesiology. 1997 Feb;86(2):331-45. doi: 10.1097/00000542-199702000-00009.

Khalil MA, Abdel Azeem MS. The impact of dexmedetomidine infusion in sparing morphine consumption in off-pump coronary artery bypass grafting. Semin Cardiothorac Vasc Anesth. 2013 Mar;17(1):66-71. doi: 10.1177/1089253212463969. Epub 2012 Oct 29. Erratum In: Semin Cardiothorac Vasc Anesth. 2023 May 30;:10892532231179573.

Taniguchi T, Kidani Y, Kanakura H, Takemoto Y, Yamamoto K. Effects of dexmedetomidine on mortality rate and inflammatory responses to endotoxin-induced shock in rats. Crit Care Med. 2004 Jun;32(6):1322-6. doi: 10.1097/01.ccm.0000128579.84228.2a.

Xu L, Bao H, Si Y, Wang X. Effects of dexmedetomidine on early and late cytokines during polymicrobial sepsis in mice. Inflamm Res. 2013 May;62(5):507-14. doi: 10.1007/s00011-013-0604-5. Epub 2013 Mar 5.

Can M, Gul S, Bektas S, Hanci V, Acikgoz S. Effects of dexmedetomidine or methylprednisolone on inflammatory responses in spinal cord injury. Acta Anaesthesiol Scand. 2009 Sep;53(8):1068-72. doi: 10.1111/j.1399-6576.2009.02019.x. Epub 2009 Jun 10.

Xiang H, Hu B, Li Z, Li J. Dexmedetomidine controls systemic cytokine levels through the cholinergic anti-inflammatory pathway. Inflammation. 2014 Oct;37(5):1763-70. doi: 10.1007/s10753-014-9906-1.

Quan H, Li B, Couris CM, Fushimi K, Graham P, Hider P, Januel JM, Sundararajan V. Updating and validating the Charlson comorbidity index and score for risk adjustment in hospital discharge abstracts using data from 6 countries. Am J Epidemiol. 2011 Mar 15;173(6):676-82. doi: 10.1093/aje/kwq433. Epub 2011 Feb 17.

Hempelmann FW. [Protein binding of xipamide (4-chloro-5-sulfamoyl-2',6'-salicyloxylidide]. Arzneimittelforschung. 1975 Feb;25(2):258-9. No abstract available. German.

Guenther U, Popp J, Koecher L, Muders T, Wrigge H, Ely EW, Putensen C. Validity and reliability of the CAM-ICU Flowsheet to diagnose delirium in surgical ICU patients. J Crit Care. 2010 Mar;25(1):144-51. doi: 10.1016/j.jcrc.2009.08.005. Epub 2009 Oct 13.

Luetz A, Heymann A, Radtke FM, Chenitir C, Neuhaus U, Nachtigall I, von Dossow V, Marz S, Eggers V, Heinz A, Wernecke KD, Spies CD. Different assessment tools for intensive care unit delirium: which score to use? Crit Care Med. 2010 Feb;38(2):409-18. doi: 10.1097/CCM.0b013e3181cabb42. Erratum In: Crit Care Med. 2010 Jun;38(6):1509.

Ritmala-Castren M, Lakanmaa RL, Virtanen I, Leino-Kilpi H. Evaluating adult patients' sleep: an integrative literature review in critical care. Scand J Caring Sci. 2014 Sep;28(3):435-48. doi: 10.1111/scs.12072. Epub 2013 Aug 26.

Gerlach AT, Murphy CV. Dexmedetomidine-associated bradycardia progressing to pulseless electrical activity: case report and review of the literature. Pharmacotherapy. 2009 Dec;29(12):1492. doi: 10.1592/phco.29.12.1492.

Sichrovsky TC, Mittal S, Steinberg JS. Dexmedetomidine sedation leading to refractory cardiogenic shock. Anesth Analg. 2008 Jun;106(6):1784-6. doi: 10.1213/ane.0b013e318172fafc.

Fischer GW, Silverstein JH. Dexmedetomidine and refractory cardiogenic shock. Anesth Analg. 2009 Jan;108(1):380. doi: 10.1213/ane.0b013e31818c0d98. No abstract available.

Saczynski JS, Marcantonio ER, Quach L, Fong TG, Gross A, Inouye SK, Jones RN. Cognitive trajectories after postoperative delirium. N Engl J Med. 2012 Jul 5;367(1):30-9. doi: 10.1056/NEJMoa1112923.

Mu DL, Wang DX, Li LH, Shan GJ, Li J, Yu QJ, Shi CX. High serum cortisol level is associated with increased risk of delirium after coronary artery bypass graft surgery: a prospective cohort study. Crit Care. 2010;14(6):R238. doi: 10.1186/cc9393. Epub 2010 Dec 30.

Verburg AF, Tjon-A-Tsien MR, Verstappen WH, Beusmans GH, Wiersma T, Burgers JS. [Summary of the 'Stroke' guideline of the Dutch College of General Practitioners' (NHG)]. Ned Tijdschr Geneeskd. 2014;158(1):A7022. Dutch.

ARDS Definition Task Force; Ranieri VM, Rubenfeld GD, Thompson BT, Ferguson ND, Caldwell E, Fan E, Camporota L, Slutsky AS. Acute respiratory distress syndrome: the Berlin Definition. JAMA. 2012 Jun 20;307(23):2526-33. doi: 10.1001/jama.2012.5669.

Gorostidi M, Santamaria R, Alcazar R, Fernandez-Fresnedo G, Galceran JM, Goicoechea M, Oliveras A, Portoles J, Rubio E, Segura J, Aranda P, de Francisco AL, Del Pino MD, Fernandez-Vega F, Gorriz JL, Luno J, Marin R, Martinez I, Martinez-Castelao A, Orte LM, Quereda C, Rodriguez-Perez JC, Rodriguez M, Ruilope LM. Spanish Society of Nephrology document on KDIGO guidelines for the assessment and treatment of chronic kidney disease. Nefrologia. 2014 May 21;34(3):302-16. doi: 10.3265/Nefrologia.pre2014.Feb.12464. Epub 2014 Mar 6. English, Spanish.

Jones AE, Puskarich MA. The Surviving Sepsis Campaign guidelines 2012: update for emergency physicians. Ann Emerg Med. 2014 Jan;63(1):35-47. doi: 10.1016/j.annemergmed.2013.08.004. Epub 2013 Sep 23.

Lin YY, He B, Chen J, Wang ZN. Can dexmedetomidine be a safe and efficacious sedative agent in post-cardiac surgery patients? a meta-analysis. Crit Care. 2012 Sep 27;16(5):R169. doi: 10.1186/cc11646.

Inouye SK, van Dyck CH, Alessi CA, Balkin S, Siegal AP, Horwitz RI. Clarifying confusion: the confusion assessment method. A new method for detection of delirium. Ann Intern Med. 1990 Dec 15;113(12):941-8. doi: 10.7326/0003-4819-113-12-941.

Li X, Yang J, Nie XL, Zhang Y, Li XY, Li LH, Wang DX, Ma D. Impact of dexmedetomidine on the incidence of delirium in elderly patients after cardiac surgery: A randomized controlled trial. PLoS One. 2017 Feb 9;12(2):e0170757. doi: 10.1371/journal.pone.0170757. eCollection 2017.

Different versions of Confusion Assessemnt Method for the Intensive Care Unit (CAM-ICU) and their validation papers were found in this web.