Fluid accumulation threshold measured by acute body weight change after admission in general surgical intensive care units: how much should be concerning?

Figures & data

Figure 1 The study flow and number of weighed patients within the first 7 days of ICU admission.

Abbreviation: ICU, intensive care unit.

Table 1 Demographic data of ICU mortality patients

Variables	All (N=465)	Survivors (N=395)	Nonsurvivors (N=70)	P-value
Median age (IQR)	60 (49–74)	60 (49–72)	53 (45–74)	0.230
Male (%)	286 (61.5)	247 (62.5)	39 (55.7)	0.280
Median admission weight in kg (IQR)	53 (45–64)	53 (45–65)	50 (44–59)	0.208
Median height in cm (IQR)	160 (153–165)	160 (153–165)	160 (153–165)	0.924
Median BMI (IQR)	20.9 (17.9–24.0)	20.9 (18.0–24.2)	20.1 (17.5–22.9)	0.217
ICU diagnosis categories (%)
Cardiovascular	71 (15.3)	64 (16.2)	7 (10.0)	0.278
Respiratory	70 (15.1)	57 (14.4)	13 (18.6)
Abdominal	206 (44.3)	175 (44.3)	31 (44.3)
Neurosurgical	2 (0.4)	2 (0.5)	0 (0)
Sepsis (unknown source)	13 (2.8)	8 (2.0)	5 (7.1)
Trauma	41 (8.8)	36 (9.1)	5 (7.1)
Metabolic	5 (1.1)	4 (1.0)	1 (1.4)
Renal and urological	41(8.8)	37 (9.4)	4 (5.7)
Obstetric and gynecological	1 (0.2)	1 (0.2)	0 (0)
Musculoskeletal and soft tissue	13 (2.8)	10 (2.5)	3 (4.3)
Others	2 (0.4)	1 (0.3)	1 (1.4)
Smoking status (%)
None	223 (48.0)	183 (46.3)	40 (57.1)	0.068
Current smoker	79 (17.0)	65 (16.5)	14 (20.0)
Ex-smoker	163 (35.0)	147 (37.2)	16 (22.9)
Postoperative status (%)	310 (66.7)	277 (70.1)	33 (47.1)	<0.001
Median initial APACHE II score (IQR)	14 (11–19)	14 (10–19)	21 (15–26)	<0.001
Median admission albumin level (mg/dL)	2.5 (1.8–3.0)	2.5 (1.9–3.1)	2.0 (1.4–2.4)	<0.001
Median of maximum weight change within 7 day in percent (IQR)	2.90 (0–6.5)	2.3 (0–6.0)	6.2 (1.4–11.3)	<0.001

Abbreviations: APACHE II, Acute Physiologic and Chronic Health Evaluation II; BMI, body mass index; ICU, intensive care unit; IQR, interquartile range.

Figure 2 The box plot of the daily percentage weight change, categorized by ICU survival status.

Note: The P-value was the value for comparison between, each day of surviving and nonsurviving patients, body weight change percentages.
Abbreviation: ICU, intensive care unit.

Figure 3 The ROC curve (A) and the intersection of sensitivity and specificity to define the optimal cutoff point (B) of Max%ΔBW for ICU mortality.

Abbreviations: CI, confidence interval; ICU, intensive care unit; Max%ΔBW, maximum percentage change in body weight; ROC, receiver-operating characteristics.

Figure 4 The OR and 95% CI of ICU mortality, categorized by six groups, of Max%ΔBW within the first week of ICU admission.

Abbreviations: CI, confidence interval; ICU, intensive care unit; Max%ΔBW, maximum percentage change in body weight; OR, odds ratio.

Table 2 Average fluid intake per day of each type of fluid, total output per day, fluid balance per day, total duration, and total fluid accumulation during surgical ICU admission†

Fluid (mL)	All (n=465)		≤5% (n=306)		>5% (n=159)		P-value**
	%‡	Median (IQR)	%‡	Median (IQR)	%‡	Median (IQR)
Total intake per day	100	3,079 (2,127–4,185)	100	2,886 (2,000–3,947)	100	3,468 (2,497–4,903)	<0.001
Crystalloid	100	2,266 (1,632–2,985)	100	2,221 (1,590–2,865)	100	2,430 (1,646–3,210)	0.043
Albumin*	20	40 (19–73)	18	50 (18–83)	23	34 (23–62)	0.405
Gelatin*	16	250 (56–670)	16	250 (56–670)	16	285 (125–1,750)	0.106
HES*	68	350 (167–800)	63	360 (167–190)	78	340 (190–790)	0.978
Packed red cells*	66	203 (94–397)	61	198 (90–408)	78	215 (95–398)	0.538
FFP*	51	359 (167–665)	43	345 (174–625)	67	362 (164–702)	0.648
Platelets*	28	90 (40–170)	21	78 (37–153)	41	101 (40–182)	0.266
Total output per day	100	1,915 (1,320–2,543)	100	1,898 (1,340–2,500)	100	1,964 (1,245–2,654)	0.732
Fluid balance per day	100	1,013 (264–2,191)	100	859 (122–1,953)	100	1,232 (499–3,117)	<0.001
Total duration of fluid administration in day	100	3 (2–6)	100	3 (2–6)	100	4 (2–9)	0.005
Total fluid accumulation	100	3,117 (795–6,690)	100	2,552 (520–5,483)	100	4,540 (2,070–9,395)	<0.001

Notes:

† Average fluid intake per day = total amount of fluid/total duration of fluid intake in a day;

* The median (IQR) was calculated only in those patients who received each type of fluid;

** Comparing the median of average daily volume between ≤5% and >5%;

‡ Percent of calculated patients who received each type of fluid or total population.

Abbreviations: FFP, fresh frozen plasma; HES, hydroxyl-ethyl starch; ICU, intensive care unit; IQR, interquartile range.

Table 3 Surgical ICU outcomes on univariable analysis of the maximum weight change cutoff point at 5% of admission body weight

Adverse events and treatment outcomes	≤5% (n=306)	>5% (n=159)	Univariable analysis (95% CI)	P-value
Categorical outcomes, n (%)			Odds ratio
ICU mortality	32 (10.5)	38 (23.9)	2.69 (1.60 to 4.51)	<0.001
With RRT (n=30)	6/11 (54.5)	11/19 (57.9)	1.15 (0.26 to 5.11)	0.858
Without RRT (n=435)	26/295 (8.81)	27/140 (19.3)	2.47 (1.38 to 4.42)	0.002
28 day mortality	52 (17.0)	44 (27.7)	1.89 (1.18 to 2.95)	0.007
With RRT (n=30)	6/11 (54.6)	12/19 (63.2)	1.43 (0.32 to 6.46)	0.643
Without RRT (n=435)	46/295 (15.6)	32/140 (22.9)	1.60 (0.97 to 2.65)	0.066
Reintubation within 72 hours	12 (3.9)	15 (9.3)	2.55 (1.16 to 5.59)	0.019
New acute kidney injury	68 (22.2)	51 (32.1)	1.65 (1.08 to 2.54)	0.022
Mechanical ventilator requirement	206 (67.3)	119 (74.8)	1.44 (0.94 to 2.22)	0.094
Vasopressor requirement	75 (24.5)	64 (40.3)	2.07 (1.38 to 3.13)	<0.001
Inotrope requirement	6 (2.0)	5 (3.1)	1.62 (0.49 to 5.40)	0.430
Delirium	38 (12.4)	37 (23.3)	2.14 (1.29 to 3.53)	0.003
RRT	11 (3.6)	19 (11.9)	3.64 (1.69 to 7.86)	0.001
Acute respiratory failure	17 (5.6)	10 (6.3)	1.14 (0.51 to 2.55)	0.748
New sepsis	111 (36.3)	65 (40.9)	1.21 (0.82 to 1.80)	0.332
Primary myocardial infarction	5 (1.6)	4 (2.5)	1.55 (0.41 to 5.87)	0.516
ICU readmission within 48 hours	15 (4.9)	12 (7.6)	1.58 (0.72 to 3.47)	0.251
Continuous outcomes, median (IQR)			Coefficient
Days of mechanical ventilator use	3 (1 to 5)	4 (2 to 10)	1.75 (0.50 to 2.99)	0.006
Days of required vasopressor agent	2 (1 to 5)	2 (1.5 to 7)	1.05 (0.39 to 1.71)	0.002
Days of required inotropic agent	3 (1 to 4)	2 (1 to 2)	-1.97 (-6.79 to 2.86)	0.380
Days of required neuromuscular blocking agent	1 (1 to 1)	1 (1 to 1)	0.08 (-0.02 to 0.19)	0.130
Days of required sedative agent	1 (1 to 2)	1 (1 to 3)	0.41 (−0.05 to 0.86)	0.079
Days of ICU length of stay	3 (2 to 3)	4 (2 to 4)	1.52 (0.21 to 2.84)	0.023

Abbreviations: CI, confidence interval; ICU, intensive care unit; IQR, interquartile range; RRT, renal replacement therapy.

Table 4 Multivariable analysis model on the outcomes in the surgical ICU, in each group of patients

Adverse events and treatment outcomes	Multivariable analysis (95% CI)
	All*	P-value	Nonoperated*	P-value	Postoperation**	P-value
Categorical outcomes	Adjusted odds ratio
ICU mortality	2.38 (1.25 to 4.54)	0.008	1.54 (0.65 to 3.68)	0.329	3.87 (1.38 to 10.85)	0.010
Without RRT	2.47 (1.21 to 5.06)	0.013	1.25 (0.47 to 3.35)	0.653	6.32 (1.85 to 21.64)	0.003
28-day mortality	1.52 (0.86 to 2.67)	0.145	1.38 (0.80 to 2.39)	0.244	1.34 (0.74 to 2.42)	0.338
Reintubation within 72 hours	2.51 (1.04 to 6.00)	0.039	1.18 (0.26 to 5.27)	0.830	4.44 (1.30 to 15.16)	0.017
New acute kidney injury	1.15 (0.68 to 1.94)	0.596	1.18 (0.52 to 2.67)	0.685	1.18 (0.58 to 2.41)	0.640
Vasopressor requirement	1.49 (0.90 to 2.50)	0.120	0.98 (0.44 to 2.21)	0.969	2.04 (1.04 to 4.01)	0.037
Delirium	1.97 (1.08 to 3.57)	0.025	3.16 (1.13 to 8.78)	0.027	1.50 (0.71 to 3.20)	0.290
Renal replacement therapy	2.67 (1.13 to 6.33)	0.026	3.53 (0.93 to 13.43)	0.065	2.00 (0.59 to 6.71)	0.260
Continuous outcomes	Adjusted coefficient
Days of mechanical ventilator use	0.85 (−0.38 to 2.08)	0.177	1.21 (−1.33 to 3.75)	0.349	0.72 (−0.64 to 2.07)	0.298
Days of required vasopressor agent	0.64 (−0.03 to 1.32)	0.061	1.07 (−0.38 to 2.52)	0.146	0.38 (−0.33 to 1.08)	0.294
Days of ICU length of stay	0.85 (−0.47 to 2.17)	0.205	1.14 (−1.47 to 3.76)	0.389	0.76 (−0.75 to 2.26)	0.322

Notes:

* Models were adjusted by admission APACHE II score, albumin level, smoking status, age, and surgical status.

** Models were adjusted by admission APACHE II score, albumin level, smoking status, and age.

Abbreviations: APACHE II, Acute Physiologic and Chronic Health Evaluation II; CI, confidence interval; ICU, intensive care unit; RRT, renal replacement therapy.