Supplemental Digital Content

Supplemental Methods

Inclusion/exclusion criteria: Patients were included who presented with severe sepsis and/or

septic shock on the day of admission to the ICU, i.e. on day 0. Day 0 had a variable amount of

hours up to a maximum of 24 hours, depending on the time of admission. Day 1 started on

midnight following admission. Patients were excluded from analysis if they were < 18 years, had

received solid organ transplantation, had renal failure requiring hemodialysis before ICU,

received extracorporeal membrane oxygenation, if serum creatinine values were missing at

admission, or if they were admitted during the 1 month wash-out period between changes in

resuscitative fluid regimens.

Sepsis was defined according to consensus conference definitions, and severe sepsis was defined

by sepsis plus at least one organ failure (27). Screening for the presence of severe sepsis or septic

shock was performed routinely by the senior ICU physicians and documented by trained research

nurses.

Severe sepsis was defined as the presence of microbiologically proven, clinically proven, or

suspected infection; presence of Systemic Inflammatory Response Syndrome (SIRS); and

development of at least one organ dysfunction within the last 24 hours. Diagnosis of SIRS

required the fulfillment of at least two of the following criteria: hypo- (≤36°C) or hyperthermia

(≥38°C), tachycardia (≥90 bpm); tachypnea (≥20 breaths/min) and/or an arterial pCO2 ≤4.3 kPa

(32 mmHg) and/or mechanical ventilation; leukocytosis ≥12,000/μl or leukopenia ≤4,000/μl

and/or a left shift in the differential white blood cell count ≥10%. For the diagnosis of organ

dysfunction one of the following criteria had to be fulfilled: presence of acute encephalopathy

with reduced vigilance, agitation, disorientation, delirium not explained by psychotropic

medication; thrombocytopenia ≤100.000/μl or a drop in the thrombocyte count >30% within 24

hours not explained by hemorrhage; arterial hypoxemia with an arterial pO2 <10 kPa (75 mmHg)

when breathing room air or an oxygenation index (paO2/FiO2 ≤33kPa (250 mmHg) not

explained by presence of a pulmonary or cardiac disease; arterial hypotension with a systolic

blood pressure ≤90 mmHg or mean arterial blood pressure ≤70 mmHg for at least one hour

despite adequate fluid loading not explained by other causes of shock; renal dysfunction with an

urine output ≤0.5 ml/kg/h for at least one hour despite adequate fluid loading and/or increase of

serum creatinine more than twofold above the reference range of the local laboratory; metabolic

acidosis with a base deficit ≥5.0 mmol/l or a serum lactate ≥ 1.5fold above the reference range of

the local laboratory.

Septic shock was defined as the presence of infection and SIRS as defined in severe sepsis as

well as presence of arterial hypotension with a systolic blood pressure ≤90 mmHg or a mean

arterial blood pressure ≤70 mmHg for at least 2 hours or administration of a vasopressor

(dopamine ≥5 μg kg-1 min-1; noradrenaline, epinephrine, phenylephrine, or vasopressin in any

dosage) to maintain systolic blood pressure ≥90 mmHg or mean arterial blood pressure ≥70

mmHg despite adequate fluid loading.

Study groups:

HES period: From 1st January 2004 until 31st January 2006, patients were treated with

predominantly 6% HES (6% HES 130/0.4; Voluven; Fresenius-Kabi, Bad Homburg,

Germany) and crystalloids. 88 % of the administered HES was 6% HES 130/0.4, the rest 10%

HES 200/0.5. Gelatin period: Standard colloid therapy was switched from 6 % HES 130/0.4 to

4% gelatin as a result of increased renal failure in association with starch use (13). From 1st

March 2006 until 31st of March 2008, patients were volume resuscitated with 4% modified

gelatin (Gelafusal; Serumwerk Bernburg AG, Bernburg, Germany) and crystalloids.

Crystalloid period: Because a prospectively planned analysis showed that the change of standard

colloid from HES to gelatin had not decreased the incidence of acute kidney injury (26), we

abandoned the use of synthetic colloids altogether. Patients received only balanced crystalloid

solutions (Jonosteril; Fresenius Kabi, Bad Homburg, Germany) except for patients with

hyperkalemia who received normal saline (NaCl 0.9%; Fresenius Kabi, Bad Homburg,

Germany). All consecutive patients with severe sepsis from 1st May 2008 until 8th April 2010

were included in this group.

Management of sepsis patients

Therapy for sepsis followed institutional standard operating procedures (SOPs) based on the

guidelines of the Surviving Sepsis Campaign (16) and the German Sepsis Society (19). During

all three study periods, hemodynamic resuscitation was guided by Early Goal Directed Therapy

(EGDT) as has been described by Rivers et al. (2) with the modification that a preset goal of

MAP of ≥ 70 mm Hg was used instead of ≥ 70 mm Hg. Briefly, hemodynamic resuscitation had

to achieve the following primary endpoints: a central venous pressure (CVP) of at least 8 mmHg,

an arterial mean blood pressure (MAP) of at least 70 mmHg, and a central venous oxygen

saturation (ScvO2) of at least 70%. Standard hemodynamic management included vasopressors

with noradrenaline to achieve preset hemodynamic goals in addition to repeated fluid challenges

with crystalloids and/or synthetic colloids (gelatin or hydroxyethyl starch) to allow the lowest

possible dose of vasopressors. Human albumin 20% was not used for volume replacement. Its

use was restricted to the treatment of severe hypoalbuminemia < 15 g/L (Albunorm 20%,

Octapharma, Langenfeld, Germany).

ScvO2 and serum lactate levels were measured by blood gas measurement (Radiometer

Copenhagen, Radiometer GmbH, Willich-Schifbahn, Germany). Extended hemodynamic

monitoring with pulmonary artery catheter (Swan-Ganz CCOmbo; Edwards Life Sciences,

Unterschleissheim, Germany) or PiCCO (Pulsiocath 5-Fr Thermodilution Catheter; Pulsion

Medical Systems Munich, Germany) was considered if the required vasopressor dose increased >

0.3 µg/kg/min of noradrenaline.

Acute kidney injury (AKI)

RIFLE “risk” was fulfilled by a 1.5-fold increase in serum creatinine levels or urine output < 0.5

mL/kg/hr (or both) for > 24 hrs, RIFLE “injury” by a two-fold increase in serum creatinine levels

or urine output < 0.3 mL/kg/hr (or both) for >24 hrs, and RIFLE “failure” was defined by a

three-fold increase in serum creatinine levels and new RRT or serum creatinine > 354 µmol/L

with an acute rise of at least 44 µmol/L or urine output < 0.3 mL/kg/hr > 24 hrs (or both) or

anuria 12 hrs for 24 hrs (41). Urine output was measured over 24 hrs and calculated back to

6- or 12- hourly values.

Continuous veno-venous hemodialysis was the single modality for RRT in our ICU during all

study periods. Indications for RRT included diuretic-resistant oliguria (urine output < 0.5 mL/kg

body weight) persistent for 6 hrs or anuria persistent for 3 hrs despite adequate volume therapy

or associated with volume overload with threatened or established pulmonary edema, the

presence of hyperkalemia, or severe metabolic acidosis (pH < 7.1).

Electronic patient data management system (PDMS)

The PDMS (Copra System GmbH, Sasbachwalden, Germany) automatically records data from

vital sign monitors, ventilators, and infusion pumps. The system also records order entries (e.g.,

medication, fluid dose and duration), laboratory and microbiology results.

Supplemental Table 1: Nephrotoxic drugs and adjunctive sepsis therapy

HES group(n = 360)

p value Gelatin group(n = 352)

p value Crystalloid group (n = 334)

NSAID, n (%)a 324 (90.0) 0.899 315 (89.5) 0.705 302 (90.4)Diuretics, n (%)b 328 (91.1) < 0.001 304 (86.4) 0.004 260 (77.8)ACE inhibitors, n (%)c 135 (37.5) 0.266 147 (41.8) 0.022 111 (33.2)Vancomycin, n (%) 115 (31.9) 0.262 98 (27.8) 0.022 121 (36.2)Aminoglycosides, n (%) d 43 (11.9) 0.635 32 (9.1) 0.523 36 (10.8)Antimycotics, n (%) e 62 (17.2) 0.537 35 (9.9) 0.038 51 (15.3)Iodinated contrast media, n (%)

80 (22.2) 0.401 70 (19.9) 0.924 65 (19.5)

Insulin, n (%)a 331 (91.9) 0.046 321 (91.2) 0.109 291 (87.1)Hydrocortisone, n (%) 169 (46.9) <0.001 208 (59.1) <0.001 79 (23.7)

HES hydroxyethyl starch. P values were calculated with Fisher’s exact test. For p value adjustment the Bonferroni-Holm method was used.a Nonsteroidal anti-inflammatory drugs, including ibuprofen and diclofenacb including mannitol and furosemidec angiotensin-converting enzyme (ACE) inhibitors, including ramipril, perindopril, lisinopril and enalaprild including tobramycin and gentamicine including amphotericin B and fluconazole

Supplemental Table 2: Parameters at onset of renal replacement therapy

HES group(n = 120)

p value Gelatin group(n = 111)

p value Crystalloid group(n = 74)

Serum creatinine (µmol/l) at onset renal replacement therapy, median [IQR]

277 [213-363]

< 0.001 162[121-244]

0.209 191[137-248]

Mean urine output at onset renal replacement therapy, (ml/kgBW/h), median [IQR]

0.19[0.06-0.49]

0.602 0.25[0.12-0.58]

0.237 0.22[0.06-0.53]

Serum potassium levels at onset renal replacement therapy, (mmol/L), median [IQR]

5.0[4.6-5.4]

0.591 4.9[4.6-5.4]

0.648 4.8 [4.6-5.3]

Serum bicarbonate levels at onset renal replacement therapy, (mmol/L), median [IQR]

20.1[17.6-22.2]

0.911 20.8[17.2-23.2]

0.331 20.1[17.7-22.2]

paO2/FiO2-ratios at onset renal replacement therapy, (%), median [IQR]

218[170-283]

0.789 203[157-270]

0.344 218[153-289]

HES hydroxyethyl starch, IQR interquartile range. P values were calculated with the Mann–Whitney test.

Supplemental Table 3: Multiple logistic regression analysis with RRT as dependent binary variable.

n Adjusted OR (95%CI) p value

Baseline creatinine: (per µmol/l) 1024 1.006 (1.004,1.008) < 0.001

Baseline SAPS-II: (per point) 1024 1.02 (1.01,1.03) < 0.001

Cardiac / thoracic surgery: yes vs. no 1024 2.96 (2.14,4.11) < 0.001

Liver cirrhosis: yes vs. no 1024 2.30 (1.31,4.03) 0.004

Antimycotics: yes vs. no 1024 1.50 (0.99,2.29) 0.057

Vancomycin: yes vs. no 1024 2.58 (1.86,3.58) < 0.001

Ionidated contrast media: yes vs. no 1024 2.32 (1.61,3.35) < 0.001

Human albumin 20%: yes vs. no 1024 2.06 (1.51,2.83) < 0.001

Added after model selection:

Period effects:Period: ref.=Crystalloids

Gelatin 4% 1024 1.92 (1.32,2.82) < 0.001

HES 6% (130/0.4) 1024 2.01 (1.34,3.02) < 0.001HES hydroxyethyl starch Variables considered in the analysis: age, liver cirrhosis, diabetes, baseline creatinine, baseline SAPS-II, cardiac / thoracic surgery, non-steroidal anti-inflammatory drugs, ACE inhibitors, aminoglycosides, antimycotics, vancomycin, ionidated contrast media, diuretics, human albumin 20%, study period using dummy coding. Forward and backward stepwise multiple logistic regression analysis based on AIC (Akaike Information Criterion) was used to derive a multivariable model where the Hosmer-Lemeshow goodness of fit test (C-test: p = 0.108, H-test: p = 0.281) and ROC curve analysis (AUC = 0.67) indicate an acceptable fit and discrimination, respectively. P values were obtained by Wald's test. After model selection the period effect was studied.

Supplemental Figure 1: Patient flow

1 Mainly patients receiving heart, lung or liver transplants. Patients undergoing renal transplantation were treated by urologists at a different location and are therefore not included.

All surgical ICU patients (1st Jan 2004 – 30th Apr 2010), n = 24326

Excluded: < 18 years n = 428Prior renal replacement therapy n = 718Solid organ transplantation1 n = 575Extracorporal membrane oxygenation (ECMO) n = 155No baseline creatinine n = 511 month wash-out period between fluid changes n = 642

HES periodn = 7069

Gelatin periodn = 7783

Crystalloid periodn = 6905

HES periodn = 7069

Gelatin periodn = 7783

Crystalloid periodn = 6905

Excluded: No criteria for severe sepsis / septic shock n = 20711

HES periodn = 360

Gelatin periodn = 352

Crystalloid periodn = 334

HES periodn = 360

Gelatin periodn = 352

Crystalloid periodn = 334

Supplemental Figure 2: Heart rate, MAP, CVP, ScvO2, hemoglobin and noradrenaline dose during the ICU stay. Daily means of heart rate, mean arterial pressure (MAP), central venous pressure (CVP), central venous saturation concentrations (ScvO2), hemoglobin values, and cumulative daily dose of noradrenaline, presented as median and interquartile ranges. ***/+++ p < .001, **/++p < .01, */+p < .05 (*comparisons between HES and crystalloid groups; +comparisons between gelatin and crystalloid groups); n denotes patients with available data.

Supplemental Figure 3: Daily procalcitonin serum levels. Presented as median and interquartile ranges, +p < .05 (+comparisons between gelatin and HES groups); n denotes patients with available data.

Procalcitonin