We conducted an observed study of consecutive patients from September to November 2016, who underwent surgical operation or with poor conservative treatment were admitted to the ICU. Of a total of 459 patients were screened in this study, 42 patients met the exclusion criteria and 11 patients did not complete delirium evaluation. Therefore, 406 patients were enrolled in the study after CAM-ICU evaluation was successfully completed. In 406 patients with our study, the primary diseases included heart and vascular disease(n = 107), abdominal disease(n = 107), pulmonary disease(n = 41), sepsis/septic shock(n = 37), cerebral disease(n = 34), maxillofacial/limbs disease(n = 29), gynecologic and obstetric disease(n = 21), urinary(n = 17) and spinal disease(n = 13). (Fig. 1).
Baseline Features and Biochemical Indicators in Patients Between Delirium and Non-delirium Groups
Of these 406 selected patients, 186 (45.8%) presented delirium during ICU stay. the mean ages of the delirium group (n = 186; 101 males) and the non-delirium group (n 220; 135males) were 60 ± 14 and 50 ± 16 years, respectively, and the age between the two groups was statistically significant(P༜0.001). Compared to the non-delirium group, the delirium group patients exhibited a significantly higher APACHE II score (14 ± 6 vs 9 ± 5; P < 0.001) and SOFA score (8 ± 5 vs 5 ± 4) .The delirium group showed bad sleep quality(P༜0.001) and significantly more history of hypertension (39% vs 25%,P = 0.003), MODS (40% vs 21%; P ༜0 .001), sedation (82% vs 65%; P ༜0 .001), and vasoactive drugs use (39% vs 29%; P = 0 .04), The delirium group also showed longer duration of ventilation (11 hours [3,27] vs 5 hours [1,10]; P < 0.001), Length of ICU stay (5.5 ± 5.4 vs 3.0 ± 2.5; P < 0.001) and higher 28-day mortality (13% vs 4%; P < 0 .001). (Table 1).
Table 1
Baseline Features and Biochemical Indicators in Patients Between Delirium and Non-delirium Groups
Variables | Delirium (n = 186) n (%) | Non delirium (n = 220) n (%) | P value |
Age, mean(SD)a, y | 60 ± 14 | 50 ± 16 | ༜0.001 |
Men | 101(54) | 135(61) | 0.151 |
History of hypertension | 73(39) | 56(25) | 0.003 |
History of cardiac disease | 55(30) | 48(22) | 0.074 |
Diabetes mellitus | 21(11) | 18(8) | 0.29 |
History of smoking | 48(26) | 73(33) | 0.105 |
History of drinking | 24(13) | 28(13) | 0.958 |
APACHEb II score, mean (SD) | 14 ± 6 | 9 ± 5 | ༜0.001 |
SOFAc score, mean (SD) | 8 ± 5 | 5 ± 4 | ༜0.001 |
MODS | 75(40) | 46(21) | ༜0.001 |
Mechanical ventilation | 156(84) | 171(78) | 0.119 |
Duration of ventilation, median (IQR)d, h | 11[3,27] | 5[1,10] | ༜0.001 |
Sedation | 152(82) | 143(65) | ༜0.001 |
Vasoactive drugs | 72(39) | 64(29) | 0.04 |
Sleep quality assessment(PSQI)e | | | ༜0.001 |
Fairly good | 5(3) | 57(26) | |
Fairly bad | 18(10) | 80(36) | |
Very bad | 163(87) | 83(38) | |
Length of ICU stay, mean (SD), d | 5.5 ± 5.4 | 3.0 ± 2.5 | ༜0.001 |
Length of hospital, mean (SD), d | 20.5 ± 11.9 | 19.5 ± 17.2 | 0.504 |
28-day mortality | 25(13) | 9(4) | 0.001 |
PH,mean(SD) | 7.37 ± 0.10 | 7.4 ± 0.1 | 0.422 |
PaO2,mean(SD) | 128.6 ± 63.2 | 135.1 ± 58.1 | 0.284 |
PaCO2,mean(SD) | 128.6 ± 63.3 | 39.3 ± 14.3 | 0.787 |
Lac,mean(SD) | 3.3 ± 8.5 | 2.1 ± 2.7 | 0.052 |
WBC,mean(SD) | 14.8 ± 6.9 | 14.2 ± 7.3 | 0.352 |
Hb,mean(SD) | 96.0 ± 24.3 | 98.5 ± 23.1 | 0.285 |
PLT,mean(SD) | 146.5 ± 73.2 | 162.7 ± 87.9 | 0.047 |
Hct,mean(SD) | 29.5 ± 7.1 | 30.6 ± 11.3 | 0.234 |
PCT, median (IQR) | 2.0[0.2,12.1] | 0.9[0.2,4.7] | 0.023 |
ALB,mean(SD) | 28.5 ± 5.9 | 29.6 ± 6.4 | 0.082 |
TBIL, median (IQR) | 15.3[9.3,31.2] | 15.9[10.3,24.3] | 0.674 |
DBIL, median (IQR) | 7.2[4.1,14.9] | 7.4[4.45,11.15] | 0.503 |
ALT, median (IQR) | 22.9[13.5,49] | 21.0[13.0,39.4] | 0.155 |
AST, median (IQR) | 40.0[24.0,98.0] | 38.6[20.7,78.3] | 0.091 |
BUN, median (IQR) | 8.5[5.4,12.7] | 6.7[4.3,10.2] | ༜0.001 |
Cr, median (IQR) | 110.0[83.0,165.0] | 92.0[72.0,123.5] | 0.027 |
UA,mean(SD) | 318.6 ± 146.4 | 297.6 ± 142.5 | 0.146 |
aSD, standard deviation; bAPACHE, Acute Physiology, age and chronic Health Evaluation; cSOFA, Sequential Organ Failure Assessment; dIQR, interquartile range; ePSQI, Pittsburgh Sleep Quality Index; |
MODS, multiple organ dysfunction syndrome;WBC, white blood cell; Hb, hemoglobin; PLT, platelet; Hct, hematocrit; PCT, procalcitonin; ALB, albumin; TBIL, total bilirubin; DBIL, direct bilirubin; ALT, glutamic-pyruvic transaminase; AST, glutamic-oxalacetic transaminase; BUN, blood urea nitrogen; Cr, creatinine; UA, uric acid. |
In biochemical indicators, compared to the non-delirium group, the delirium group showed significantly higher PCT(2.0[0.2,12.1] vs 0.9[0.2,4.7],P = 0.023), BUN (8.5[5.4,12.7] vs 6.7[4.3,10.2],P༜0.001)and Cr(110.0[83.0,165.0] vs 92.0[72.0,123.5],P = 0.027), while PLT(146.5 ± 73.2 vs 162.7 ± 87.9,P = 0.047) was significantly lower. A significant difference was not observed in the other indicators between the two groups (P < 0 .05). (Table 1).
The incidence and risk factors for delirium in different disease types
The overall incidence of ICU delirium was 45.8% (186/406), and the incidence of different diseases is different, from 15% (spine disease) to 68% (cerebral disease). The incidence of delirium was highest in patients with cerebral disease (68%), followed by pulmonary disease (63%), maxillofacial/limbs disease (52%), sepsis/ septic shock (49%), heart and vascular disease (44%) and abdominal disease (42%). (Fig. 2)
A multiple logistic regression was conducted, with delirium as a dependent covariate. The variables that were introduced in the logistic regression model were the result of the univariate analysis that preceded the multivariate analysis; the variables that were introduced in the model were those that showed a statistically significant relationship at the level of 0.05 (p < 0.05) with the dependent variable (occurrence of delirium), we reached the conclusion that for all patients, age, APACHE II score, sedation, and duration of ventilation were independent risk factors for delirium. For example, the older patients are more likely to develop delirium (OR = 1.756, p = 0.001), patients who have a higher APACHE II score were more susceptible to develop delirium (OR = 1.093, p = 0.001), patients who had longer duration of ventilation were more susceptible to develop delirium (OR = 1.022, p = 0.012). In addition, patients who underwent sedation (OR = 3.406, p༜0.001) were prone to develop delirium more frequently. While good sleep quality was a protective factor for delirium (OR = 0.186, p < 0.001). (Table.2)
However, the risk factors are different for different type of disease. For heart and vascular disease subgroup, only sleep quality (OR = 0.236, p༜0.001) was independent risk factor for delirium. For abdominal disease subgroup, age (OR = 2.514, p = 0.002), vasoactive drugs (OR = 13.799, p = 0.002), and sleep quality (OR = 0.114, p༜0.001) were risk factors for the delirium. And for sepsis and septic shock subgroup, age(OR = 1.100, p = 0.022), APACHE II scores(OR = 1.255, p༜0.001) and sleep quality (OR = 0.090, p = 0.034) were risk factors for the delirium. But our study shows no significant risk factor for delirium in lung diseases and cerebral diseases subgroup, which may be related to the reasons for fewer cases. (Table 2)
Table 2
Multivariate regression analysis of risk factors for delirium as dependent variable in all patients and different diseases types
Variables | All patients (n = 406) [P;(ORa,95%CIb)] | Heart and vascular disease (n = 104) [P;(OR,95%CI)] | Abdominal disease (n = 92) [P;(OR,95%CI)] | Sepsis/Septic shock (n = 37) [P;(OR,95%CI)] | Cerebral disease (n = 31) [P;(OR,95%CI)] | Pulmonary disease(n = 36) [P;(OR,95%CI)] |
Age, y | 0.001;( 1.756,1.406–2.194) | — | 0.002;(2.514,1.397–4.524) | 0.022;(1.100,1.014–1.194) | — | — |
APACHE II score | 0.001;(1.093, 1.039–1.150) | — | — | ༜0.001;(1.255,1.112–1.417) | — | — |
Sedation | ༜0.001;(3.406, 1.867–6.212) | — | — | — | — | — |
Vasoactive drugs | — | — | 0.002;(13.799,2.669–71.361) | — | — | — |
Sleep quality assessment (PSQI) | ༜0.001;(0.186, 0.121–0.288) | ༜0.001;(0.236, 0.111-0.500) | ༜0.001;(0.114,0.036–0.366) | 0.034;(0.09,0.010–0.829) | — | — |
Duration of ventilation | 0.012;(1.022,1.005–1.040) | — | — | — | — | — |
aOR, odds ratio; b95%CI, 95% confidence intervals;“—” means P has no statistically significant. |
The prognosis of delirium in different diseases types
A multivariate stepwise Cox regression model was used to analyze the length of ICU stays and 28 days survival time between delirium and non-delirium groups. Our study found that in all patients group, delirium group exhibited a significantly longer ICU stays (P < 0.001) and higher 28-day mortality(P = 0.001) than the non-delirium group.
The difference of ICU stays between delirium and non-delirium groups in the subgroup of heart and vascular disease(P < 0.001), pulmonary disease(P = 0.011), sepsis/septic shock(P < 0.001) and cerebral disease(P = 0.011) were consistent with the general population. while the differences between the abdominal disease subgroups were insignificant(P = 0.47). (Fig. 3)
But the sepsis/septic shock subgroup was the only one whom has the significant difference in 28-day mortality between delirium and non-delirium groups (P = 0.006). (Fig. 4)