Trauma is a leading cause of disability and death among young people in the developed world [
In general, acute kidney injury (AKI) is rare among trauma patients and is quite modestly described [
Thus, the aim of this retrospective study was to describe posttraumatic AKI treated with CRRT in adults focusing upon the primary traumatic injuries and secondary organ failures. We also assessed time from trauma to initiation of CRRT (early versus late CRRT) and diuresis at initiation of CRRT (oliguric versus nonoliguric AKI).
OUHU is a major Scandinavian trauma centre currently admitting approximately 1800 trauma patients per year. It serves as a regional trauma centre for 2.7 million people, more than half the Norwegian population. Adult trauma patients (>18 years) admitted to OUHU between January 1, 1997, and December 31, 2006, were retrospectively reviewed, as a substudy of a previous report on the same patients [
Simplified acute physiology score (SAPS) II was used to describe severity of illness [
Patients with a trauma responding for their present ICU stay were identified by searching all available diagnosis codes for trauma, excluding foreign bodies, late effects, and complications not directly related to the primary injury. AKI was developed and defined in the patients, using not only diagnosis codes for acute renal failure, but also procedure codes for CRRT. Different electronic databases were cross checked to ensure that no patients were missed, that is, the institutional hospital charts, local trauma registry, and ICU registry, and also the Norwegian national renal registry.
Categorical data are presented as number (percent) and compared using a two-sided Pearson’s chi-square test. Continuous data are presented as median (interquartile range (IQR)) and compared using a 2-tailed Mann-Whitney
Among 506 trauma patients admitted to the ICU, 42 (8%) developed AKI with need of CRRT and were included in the study. Median age was 46 years, and 86% were male. Seventeen (41%) patients had rhabdomyolysis, whereof 15 were treated with forced alkaline diuresis. None of the patients were dialysis-dependent three months after initiation of CRRT, and three-month mortality was 36% (Table
Patient characteristics, trauma mechanism, and organ injuries in trauma patients with acute kidney injury treated with continuous renal replacement therapy (
Demographic data | |
Age (years) | 46 (29–64) |
Male gender | 36 (86) |
SAPS II score | 40 (32–48) |
ISS score | 36 (27–49) |
SOFA score | 13 (12–15) |
Time from trauma to CRRT (days) | 5 (3–11) |
Duration of any RRT (days) | 6 (4–15) |
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Trauma mechanisms | |
Blunt trauma | 40 (95) |
Car | 17 (41) |
Squeeze | 10 (24) |
Motorcycle | 7 (17) |
Pedestrian | 2 (5) |
Fall | 2 (5) |
Gun | 2 (5) |
Train | 1 (2) |
Explosion | 1 (2) |
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Primary organ injuries | |
Central nervous system | 9 (21) |
Thorax | 30 (71) |
Abdomen | 27 (64) |
Pelvis | 22 (52) |
Multiple fractures | 32 (76) |
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Outcome | |
Intensive care unit length of stay (days) | 26 (12–46) |
Dialysis-dependent 3 months | 0 (0) |
3-month mortality | 15 (36) |
Categorical data are presented as number (percent) and continuous data as median (interquartile range). SAPS II: simplified acute physiology score II.
ISS: injury severity score. SOFA: sequential organ failure assessment.
CRRT: continuous renal replacement therapy. RRT: renal replacement therapy. RIFLE: risk, injury, failure, loss, and end-stage renal disease.
The patients were severely traumatized with median ISS 36 (IQR, 27–49). Blunt trauma was the injury mechanism in 40 (95%), mainly traffic accidents. Most of the patients had primary organ injuries in several body regions, most frequently in thorax and abdomen, affecting 30 (71%) and 27 (64%) of the patients, respectively. Orthopedic injuries were also common, with 22 (52%) of the patients having pelvis fractures and 32 (76%) multiple fractures. Primary injuries in the central nervous system affected nine (21%) of the patients (Table
The trauma patients were severely ill with median SAPS II score 40 (IQR, 32–48). Within the first 24 hours after hospital admission, median maximum heart rate was 125 (IQR, 113–143) beats per minute, and median minimum systolic blood pressure was 68 (IQR, 55–72.5) mmHg. Inotropic and/or vasoactive medications were used in 28 (67%) of the patients, and the number of packed red blood cell (PRBC) transfusions was median 11 (IQR, 4–26). Furthermore, 39 (93%) of the patients were intubated. Even though they subsequently developed AKI with need of CRRT, the daily urine output at admission day was median 2420 (IQR, 1610–3580) mL. Within the first day, 38 (90%) and nine (21%) patients underwent surgical and radiological procedures, respectively (Table
Organ functions and performed procedures in trauma patients with acute kidney injury treated with continuous renal replacement therapy (
Organ function at admission day | |
Maximum heart rate | 125 (113–143) |
Arrhythmias | 3 (7) |
Minimum systolic blood pressure | 68 (55–72.5) |
Inotropic and/or vasoactive medications | 28 (67) |
Intubation | 39 (93) |
Highest FiO2 | 0.7 (0.5–0.9) |
Highest peak inspiratory pressure (cmH2O) | 29 (26–32) |
Highest positive end expiratory pressure (cmH2O) | 8 (6–10) |
Diuresis (mL) | 2420 (1610–3580) |
Lowest blood base excess (mmol/L) | −10 (−5–−10) |
Highest blood glucose (mmol/L) | 10 (8–12) |
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Surgical, radiological, or other procedures at admission day | |
Fasciotomy | 11 (26) |
Amputation | 10 (24) |
Endovascular embolization | 9 (21) |
Vascular surgery | 6 (14) |
Thoracotomy | 6 (14) |
Laparotomy | 16 (38) |
Peritoneal lavage | 7 (17) |
Peritoneal lavage and laparotomy | 3 (7) |
Orthopedic surgery | 18 (43) |
Total operative time (minutes) | 265 (132–401) |
PRBC transfusions (number) | 11 (4–26) |
Categorical data are presented as number (percent) and continuous data as median (interquartile range). FiO2: fraction of inspired oxygen.
PRBC: packed red blood cell.
Time from trauma to initiation of CRRT among the 42 patients was median five (IQR, 3–11) days. The most frequent organ malfunctions were respiratory and cardiovascular failure, affecting 33 (75%) and 30 (71%) of the patients when assessed by SOFA score 3 or 4, respectively. Additionally, 29 (69%) patients had kidney failure when assessed by SOFA score 3 or 4, whereas failure of the central nervous system, liver, and/or coagulation system was rather infrequent (Figure
The organ failures measured by sequential organ failure assessment (SOFA) score in trauma patients with acute kidney injury and need of continuous renal replacement therapy (
Patients with early initiation of CRRT had significantly higher peak serum CK concentrations compared to the patients with late initiation of CRRT (median (IQR) 9643 (2775–43434) U/L versus 317 (101–2499) U/L, resp.,
Subgroups analyses of trauma patients with acute kidney injury treated with continuous renal replacement therapy (
Early versus late initiation of CRRT | ||||
Days from trauma to initiation of CRRT ≤5 days (early) or >5 days (late) | ||||
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Overall ( |
Early ( |
Late ( |
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PRBC transfusions (number) | 11 (4–26) | 10 (3–23) | 13.5 (5.5–26.25) | 0.45 |
Serum creatine kinase (U/L) | 3814 (575–25487) | 9643 (2775–43434) | 317 (101–2499) | <0.01 |
Multiple organ failure | 27 (64) | 16 (69) | 11 (58) | 0.43 |
Mortality | 15 (36) | 6 (26) | 9 (47) | 0.15 |
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Oliguric versus nonoliguric acute kidney injury | ||||
Daily diuresis at initiation of CRRT ≤500 mL (oliguric) or >500 mL (nonoliguric) | ||||
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Overall ( |
Oliguric ( |
Nonoliguric ( |
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Diuresis admission day (mL) | 2420 (1610–3580) | 2020 (1375–2808) | 2666 (1858–3680) | 0.81 |
Days to CRRT |
5 (3–11) | 4 (2–6.25) | 7 (3–13) | <0.01 |
Multiple organ failure | 27 (64) | 13 (81) | 14 (58) | 0.07 |
Mortality | 15 (36) | 7 (44) | 8 (31) | 0.39 |
Categorical data are presented as number (percent) and compared using 2-sided Pearson’s Chi-squared test. Continuous data are presented as median (interquartile range) and compared using 2-tailed Mann-Whitney
CRRT was initiated significantly earlier in patients with oliguric severe AKI than in patients with nonoliguric severe AKI (median (IQR) 4 (2–6.25) days versus 7 (3–13) days, resp.,
We have shown in 42 trauma patients that AKI treated with CRRT was often a consequence of blunt trauma mechanisms with severe injuries to several body regions simultaneously. The majority of the patients had respiratory (93%) and cardiovascular (67%) failure within 24 hours after admission. Even though most patients seemed to have an adequate diuresis at admission day, they still developed AKI with need of RRT. There was a delay from the initial trauma to initiation of RRT of median five days. Severe AKI was often part of MOF, and the most frequent concomitant organ malfunctions were respiratory (75%) and cardiovascular (71%) failure, respectively.
AKI is a severe complication in trauma patients associated with a several-fold increase in hospital death; it is especially hazardous in the most severe cases where CRRT is being used [
The present trauma patients with AKI undergoing CRRT were severely injured with a high ISS, and 64% had primary abdominal injuries. High ISS scores have previously been found in patients with posttraumatic AKI [
Severity of illness [
Although it seems obvious to detect AKI as early as possible, we found no significant association between the time of initiation of CRRT and mortality. However, the number of patients was low. Previous data do indicate that early initiation of RRT may have a beneficial impact on survival in general ICU patients [
In a study of general ICU patients, oliguric severe AKI was associated with worse renal outcomes and mortality compared to nonoliguric severe AKI [
This study has some important limitations as it presents only a small number of patients from a single trauma centre. Additionally, only the most severe type of posttraumatic AKI is included, that is, those receiving CRRT. Combined with a wide variation in the practical performance of CRRT among institutions, the external validity of the findings probably is limited. Further, the subgroup analyses should be interpreted with caution because of the small number of patients in each group with limited statistical power (type II error). The definitions of the subgroups, that is, oliguric/nonoliguric and early/late, may also vary among studies. Indeed, prospective studies in this complex subgroup of ICU patients are needed in the future for better-targeted treatment and reduction in mortality.
Trauma patients with AKI treated with CRRT were often victims of blunt trauma with severe primary organ injuries in several body regions. There was a time delay of several days from the initial trauma to the need of CRRT in most patients, and AKI was frequently associated with MOF.
The authors declare that there is no conflict of interests regarding the publication of this paper.
The authors are grateful to Rolf Haagensen and Morten Hestnes for providing data from the institutional intensive care and trauma registries. The study was founded by departmental grants only.