Table 2.

Urine output: multivariate analysis

Variable	Effect estimate (95% CI)	P
CRRT status (after v before)	–0.092 (–0.150 to –0.034)	0.002*
Time (per hour)
Before CRRT	–0.012 (–0.015 to –0.010)	< 0.001*
On CRRT	–0.006 (–0.002 to –0.011)	< 0.001*
Noradrenaline equivalent†
0.01–0.10 μg/kg/min	–0.135 (–0.182 to –0.087)	< 0.001*
0.11–0.20 μg/kg/min	–0.183 (–0.233 to –0.133)	< 0.001*
> 0.20 μg/kg/min	–0.238 (–0.287 to –0.189)	< 0.001*
MAP (per 10 mmHg)	0.053 (0.041 to 0.065)	< 0.001*
NUF
0.1-1.15 mL/kg/h	0.076 (0.022 to 0.130)	0.006*
> 1.15 mL/kg/h	0.011 (–0.039 to 0.061)	0.6674
Mode/blood flow‡	–0.015 (–0.215 to 0.184)	0.8808
Admission creatinine level, μmol/L§	0.004 (–0.036 to 0.044)	0.8442
Admission diagnosis
Other surgical	–0.017 (–0.452 to 0.419)	0.94
Sepsis	0.100 (–0.322 to 0.522)	0.64
Other medical	0.100 (–0.294 to 0.494)	0.62
Sex, male	–0.069 (–0.277 to 0.139)	0.52
Age, years	–0.009 (–0.015 to -0.003)	0.006*
APACHE III ROD**
30–49%	–0.279 (–0.577 to 0.019)	0.0686
50–74%	–0.073 (–0.377 to 0.231)	0.64
≥ 75%	–0.173 (–0.476 to 0.13)	0.26
CRRT commenced day 1††	0.116 (–0.094 to 0.326)	0.28

APACHE = Acute Physiology and Chronic Health Evaluation; CRRT = continuous renal replacement therapy; ICU = intensive care unit; IQR = interquartile range; MAP = mean arterial pressure; NUF = net ultrafiltration rate; ROD = Risk of Death.

^*P < 0.05.

^†Versus 0 μg/kg/min noradrenaline equivalent, measured hourly at the time of the urine output measurement.

^‡Mode and blood flow are interlinked, continuous venovenous haemodiafiltration (CVVHDF) protocol was blood flow 200–250 mL/h, continuous venovenous haemodialysis (CVVHD) was 120–130 mL/h, estimate is for CVVHDF versus CVVHD.

^§Effect estimate in increments of 1 μmol/L; Versus cardiac surgical.

^**Versus 0–29%.

^††Versus day 2 or later. Day 1 is defined as CRRT commencing with 24 hours of ICU admission.