Incidence of SA‑AKI
From 1 January 2022 to 31 December 2022, a total of 121 patients underwent CRRT while in the ICU. We excluded 6 patients transferred between facilities, 4 patients with end-stage renal disease, and 3 patients with palliative hospitalisation. Of the remaining 108 patients, 59 in met the criteria for SA-AKI. Over time, an increasing proportion of patients meeting the criteria for SA-AKI have been treated with CRRT, with a progressive increase in treatment outcomes.
Patient characteristics
The overall patient characteristics, inclusive of both non-SA-AKI and SA-AKI patients, are shown in Table 1. Most of the patients with SA-AKI had a primary disease of the respiratory system, followed by a disease of the gastrointestinal system, as can be seen in Fig. 1. They were older [60.0 (51.0–72.0) years vs. 73.0 (65.0–78.0) years, P < .05] and had statistically significant differences in higher APACHE II [21 (19–25) vs. 11 (15–17), P < .05] and SOFA scores [12 (11–14) vs.8 (7–9), P < .05]. On admission to the ICU, SA-AKI and non-SA-AKI patients had largely similar levels of inflammation and liver function. However, there were significant differences between the two groups in terms of creatinine levels and arterial blood gases. The SA-AKI patients had less severe renal impairment [254.3 (165.4-380.9) µmol/L vs. 506.8(274.9-700.6) µmol/L, P < .05], low PH [(7.3 ± 0.1) vs. (7.4 ± 0.1), P < .05], PaO2 [93.2 (77.0-130.5) mmHg vs. 129.0(95.0-164.0) mmHg, P < .05], PaO2/FIO2 [180.0 (128.0- 255.5)mmHg vs. 310.0(214.0-339.0)mmHg, P < .05] and high lactic acid [2.7 (1.7-4.0) mmol/L vs. 1.4 (0.8–3.7) mmol/L, P < .05], suggesting that these had more severe pulmonary impairment, required more mechanical ventilation, and had a higher risk of death.
APACHE II scores Acute Physiology and Chronic Health Evaluation II scores, SOFA scores Sequential Organ Failure Assessment scores, PLT Platelet count
Table 1 Baseline characteristics
|
Septic(n=59)a
|
Non-septic(n=49)a
|
P valueb
|
Sex
|
|
|
|
Male [n (%)]
|
41 (69.5%)
|
37 (75.5%)
|
.632
|
Age (years)
|
60.0 (51.0-72.0)
|
73.0 (65.0-78.0)
|
<.001
|
BMI (kg/m2)
|
21.0 ± 3.7
|
21.3 ± 3.5
|
.677
|
Hypertension [n (%)]
|
36 (61%)
|
34 (69.4%)
|
.481
|
Diabetes mellitus [n (%)]
|
19 (32.2%)
|
23 (46.9%)
|
.172
|
APACHE Ⅱ
|
21 (19-25)
|
11 (15-17)
|
<.001
|
SOFA
|
12 (11-14)
|
8 (7-9)
|
<.001
|
Laboratory data
|
|
|
|
Leukocytes (109/L)
|
10.7 (7.4-15.3)
|
11.5 (8.2-18.0)
|
.276
|
Neutrophil (109/L)
|
8.6 (6.0-13.5)
|
9.1 (6.8-15.8)
|
.363
|
Lymphocytes (109/L)
|
0.6 (0.4-1.1)
|
0.7 (0.5-1.2)
|
.310
|
PLT (109/L)
|
140.0 (93.0-230.0)
|
136.0(54.0-186.0)
|
.283
|
Hemoglobin (g/L)
|
87.0 (77.5-101.0)
|
85.0(72.0-108.0)
|
.765
|
C-reactive protein (mg/L)
|
81.0 (39.8-168.6)
|
100.9(62.7-190.1)
|
.252
|
Creatinine (μmol/L)
|
254.3 (165.4-380.9)
|
506.8(274.9-700.6)
|
<.001
|
Urea (mmol/L)
|
19.0 (13.2-33.0)
|
20.1 (14.3-30.1)
|
.890
|
Bilirubin (μmol/L)
|
17.3 (11.9-35.9)
|
15.7 (9.1-37.5)
|
.596
|
Alanine aminotransferase (U/L)
|
24.8 (16.9-75.2)
|
19.1 (12.1-73.4)
|
.363
|
Aspartate aminotransferase (U/L)
|
49.0 (27.5-160.0)
|
33.0(22.0-150.0)
|
.265
|
Arterial Blood Gas
|
|
|
|
PH
|
7.3 ± 0.1
|
7.4 ± 0.1
|
.005
|
PaO2 (mmHg)
|
93.2 (77.0-130.5)
|
129.0(95.0-164.0)
|
.005
|
PaCO2 (mmHg)
|
38.1 (29.6-49.2)
|
35.0 (31.3-39.5)
|
.190
|
PaO2/FIO2 (mmHg)
|
180.0 (128.0- 255.5)
|
310.0(214.0-339.0)
|
<.001
|
Lactate (mmol/L)
|
2.7 (1.7-4.0)
|
1.4 (0.8-3.7)
|
.005
|
APACHE II scores Acute Physiology and Chronic Health Evaluation II scores, SOFA scores Sequential Organ Failure Assessment scores, PLT Platelet count
a Median (IQR) or frequency (%)
b Pearson’s Chi-squared test or Fisher’s exact test
As shown in Table 2, we examined outcomes based on the AKI diagnostic criteria met. SA-AKI patients had a longer duration of mechanical ventilation [11 (4–23) days vs. 4 (1–10) days, P < .05] and ICU stay [13 (6.5–24) days vs. 8 (5–16) days, P < .05], whereas the total length of hospital stay, incidence of bleeding and arrhythmia, and recovery of renal function were similar. 7-day mortality was not significantly different, but the 28-day mortality rate [35 (59.3%) vs. 14 (28.6%), P < .05] was significantly higher in SA-AKI patients and approximately twice as high as in non-SA-AKI patients with CRRT.
Figure 2 illustrates the infectious events that occurred during hospitalization in AKI patients treated with CRRT, with Klebsiella pneumoniae infection being the greatest risk, followed by Acinetobacter baumannii. 44% of the patients had mixed infections of two or more species, and only 21% of the patients were not tested for any species.
After multivariate COX regression analysis (table 3), SA-AKI patients' age (HR,0.978; 95%CI 0.957-1.000; P < .05) and lactate level (HR,1.146; 95%CI 1.018–1.291; P < .05) were independent risk factors for 28-day mortality.
Table 2 Associated outcomes
|
Septic(n=59)a
|
Non-septic(n=49)a
|
P valueb
|
7-day mortality
|
9.0 (15.3%)
|
4.0 (8.2%)
|
.262
|
28-day mortality
|
35 (59.3%)
|
14 (28.6%)
|
.003
|
Renal recovery [n (%)]
|
15 (25.4%)
|
11 (22.4%)
|
.893
|
Days on mechanical ventilation (days)
|
11 (4-23)
|
4 (1-10)
|
<.001
|
ICU stay (days)
|
13 (6.5-24.0)
|
8 (5-16)
|
.037
|
Hospital stay (days)
|
19 (12-37)
|
24 (16-38)
|
.406
|
Bleeding
|
|
|
|
Gastrointestinal bleeding [n (%)]
|
26 (44.1%)
|
14 (28.6%)
|
.144
|
Respiratory haemorrhage [n (%)]
|
8 (13.6%)
|
4 (8.2%)
|
.561
|
Cerebral haemorrhage [n (%)]
|
8(13.6%)
|
8(16.3%)
|
.896
|
Arrhythmia [n (%)]
|
28 (47.5%)
|
15 (30.6%)
|
.113
|
ICU Intensive care unit
a Median (IQR) or frequency (%)
b Pearson’s Chi-squared test or Fisher’s exact test
Table 3 Multivariate Cox Regression Model mortality for SA-AKI patients undergoing CRRT treatment.
|
HR
|
95 % CI
|
P value
|
Age (years)
|
0.978
|
0.957-1.000
|
.046
|
Lactate (mmol/L)
|
1.146
|
1.018-1.291
|
.024
|
95 % CI 95 % confidence interval.