Risk factors for delirium after cardiovascular surgery: a retrospective study of 7 001 cases / 中国医师进修杂志

ABSTRACT

Objective:To investigate the incidence of delirium and related risk factors in patients after cardiovascular surgery.Methods:From May 2012 to May 2019, 7 001 patients underwent cardiovascular surgery in the Nanjing First Hospital were retrospectively analyzed. The general clinical data, operation name, operation time, cardiopulmonary bypass time, aortic occlusion time, analgesic and sedative drugs use during postoperative ICU treatment, confusion assessment method for the intensive care unit (CAM-ICU) score, length of ICU stay, total hospital stay, adverse prognosis and postoperative delirium were recorded. The influence of postoperative delirium on hospital stay and adverse prognosis was analyzed. The risk factors of postoperative delirium were explored.Results:Among the 7 001 patients, 573 (8.18%) had postoperative delirium (delirium group), while 6 428 patients had no delirium (non-delirium group). The incidence of postoperative delirium in patients with acute aortic dissection (AAD) after Sun′s operation was significantly higher than that in patients with other cardiovascular surgery 45.03% (204/453) vs. 5.64% (369/6 548), and there was statistical difference ( P<0.05). The age, length of ICU stay, total hospital stay, incidence of adverse prognosis, operation time, cardiopulmonary bypass time and aortic occlusion time in delirium group were significantly higher than those in non-delirium group (59.72 ± 12.48) years vs. (58.81 ± 12.16) years, 5.49 (2.87, 9.49) d vs. 1.12 (0.90, 1.95) d, 21.92 (17.90, 28.22) d vs. 17.85 (14.93, 21.76) d, 7.33% (42/573) vs. 2.13% (137/6 428), (5.43 ± 2.51) h vs. (4.06 ± 1.33) h, (140.01 ± 55.13) min vs. (108.07 ± 42.98) min and (85.23 ± 37.30) min vs. (72.50 ± 34.15) min, and there were statistical differences ( P<0.01). Multivariant Logistic regression analysis result showed that intraoperative deep hypothermic circulatory arrest and selective cerebral perfusion was independent risk factor of postoperative delirium in patients with cardiovascular surgery ( OR = 10.922, 95% CI 7.444 to 16.120, P < 0.01). After excluding AAD patients, the incidences of postoperative delirium were 2.63% (11/418), 4.16% (34/817), 4.37% (71/1 625), 5.13% (122/2 379), 9.34% (114/1 221) and 19.32% (17/88) for patients<40 years, 40 to 49 years, 50 to 59 years, 60 to 69 years, 70 to 79 years and ≥ 80 years respectively. The incidence of postoperative delirium increased with age ( Z= 2.63, P= 0.009). The incidences of postoperative delirium were 1.47% (45/3 056), 3.22% (63/1 954), 5.69% (34/597), 12.14% (38/312), 18.18% (22/121), 22.62% (38/168), 25.93% (21/81) and 41.70% (108/259) for patients who stayed 1, 2, 3, 4, 5, 6, 7 and>7 d in ICU. The longer stay in ICU, the higher the incidence of postoperative delirium ( Z= 3.34, P = 0.001). Sequential organ failure score (SOFA) was used to evaluate the organ functions of patients. The scores of respiratory system, circulatory system, liver function and renal function in delirium group were significantly worse than those in non-delirium group, and there were statistical differences ( P<0.01); there was no significant difference in coagulation function between 2 groups ( P > 0.05). According to the use of analgesic and sedative drugs during the postoperative ICU stay, the patients were divided into dexmedetomidine alone group (3 355 cases) and dexmedetomidine combined with dezocine group (1 396 cases). The incidence of postoperative delirium in dexmedetomidine combined with dezocine group was significantly higher than that in dexmedetomidine alone group 19.20% (268/1 396) vs. 5.66% (190/3 355), and there was statistical difference ( P<0.01). Conclusions:Age, operation time, extracorporeal circulation time, aortic occlusion time, intraoperative hypothermic circulatory arrest with selective cerebral perfusion, severity of disease and length of ICU stay are independent risk factors for postoperative delirium in patients after cardiovascular surgery. The choice of analgesic and sedative drugs during the perioperative period may affect the occurrence of postoperative delirium.