Serum sodium shift in hyponatremic patients undergoing liver transplantation: a retrospective cohort study

Figures & data

Table 1. Summary of baseline characteristics and pre-operative physiology, laboratory values and interventions.

Variables	Total (n = 69)	SNa < 10 mmol/L (n = 63)	SNa ≥10 mmol/L (n = 6)	p-Value
Age at time of LT (mean [SD]) (years)	53.3 (10.3)	53 (10.5)	57 (7.8)	0.369
Male sex (%)	44 (64)	40 (63)	4 (66)	0.916
MELD Score (mean [SD])	24.2 (8.5)	24.2 (8.6)	23.5 (8.7)	0.834
Indication for Lx transplantation*
Hepatitis C virus	26 (38)	25 (40)	1 (17)	0.255
Alcoholic cirrhosis	16 (23)	14 (22)	2 (33)	0.553
Hepatocellular carcinoma	14 (20)	13 (21)	1 (17)	0.804
Other indications	32 (46)	29 (46)	3 (50)	0.880
Disposition at time of LT (%)				0.02
Home	13 (43.3)	13 (54.2)	0 (0)
Hospitalized	12 (40.0)	7 (29.2)	5 (83.3)
ICU	5 (16.7)	4 (16.7)	1 (16.7)
Living donor (%)	11 (16)	10 (16)	1 (17)	0.960

Notes: *More than one indication may apply.

LT = liver transplant; MELD = model for end-stage liver disease; ICU = intensive care unit; RRT = renal replacement therapy.

Table 2. Details of peri-operative serum sodium shift, and intra/post-operative interventions.

Variables	Total (n = 69)	SNa <10 mmol/L (n = 63)	SNa ≥ 10 mmol/L (n = 6)	p-Value
Pre-operative sodium (SNa) (mean [SD]) (mmol/L)	129 (3)	129 (2)	126 (4)	0.047
ΔSNa at 24 h (mean [SD]) (mmol/L)	4.1 (3.9)	3.3 (2.9)	12.8 (1.9)	<0.001
Post-operative SNa at 24 h (mean [SD]) (mmol/L)	133 (4)	132 (4)	139 (4)	<0.001
ΔSNa at 48 h (mean [SD]) (mmol/L)	5.4 (3.8)	4.9 (3.6)	10.5 (1.3)	<0.001
Post-operative SNa at 48 h (mean [SD]) (mmol/L)	134 (4)	134 (4)	137 (4)	0.056
Increase in SNa >10 mmol/L at 48 h (%)	8 (12)	3 (5)	5 (83)	<0.001
Operative duration (mean [SD]) (min)	406 (142)	408 (134)	389 (224)	0.761
Intra-operative fluid balance (med [P25–P75]) (L)	5.6 (4.0–7.75)	5.2 (3.8–7.2)	9.8 (8.1–26.3)	<0.001
Post-operative fluid balance at 24 h (med [P25–P75]) (L)	3.0 (1.2–5.2)	2.5 (0.9–5.1)	4.9 (3.5–7.2)	0.077
Intra-operative CRRT (%)	11 (16)	8 (13)	3 (50)	0.017
Post-operative RRT (%)	12 (17)	10 (16)	2 (33)	0.281
Intra-operative vasopressors (%)
Any (%)	69 (100)	63 (100)	6 (100)	–
Vasopressin (%)	54 (78)	49 (78)	5 (83)	0.753
Post-operative vasopressors (%)
Any (%)	43 (62)	39 (62)	4 (67)	0.818
Vasopressin (%)	27 (39)	23 (37)	4 (67)	0.148
Post-operative corticosteroids (%)	11 (16)	8 (13)	3 (50)	0.017
Post-operative diuretics (%)	16 (23)	15 (24)	1 (17)	0.692

Notes: SNa = serum sodium; CRRT = continuous renal replacement therapy; RRT = renal replacement therapy.

Table 3. Summary of clinical outcomes.

Variables	Total (n = 69)	SNa <10 mmol/L (n = 63)	SNa ≥10 mmol/L (n = 6)	p-Value
Duration of MV (med [P25–P75]) (days)	2 (1–3)	1 (1–3)	3 (1–33)	0.189
Re-intubation required (%)	16 (23)	13 (21)	3 (50)	0.109
Difficult to wean from mechanical ventilation (%)	14 (20)	12 (19)	2 (33)	0.406
Tracheostomy (%)	10 (14)	8 (13)	2 (33)	0.170
ICU length of stay (med [P25–P75]) (days)	4 (2–8)	5 (2–12)	8 (3–71)	0.337
MET activation (%)	15 (22)	13 (21)	2 (33)	0.471
ICU re-admission (%)	15 (22)	13 (21)	2 (33)	0.471
Brain CT (%)	16 (23)	12 (19)	4 (63)	0.008
Brain MRI (%)	15 (22)	13 (21)	2 (33)	0.471
EEG (%)	6 (9)	5 (8)	2 (33)	0.049
Abnormal mental status (%)	24 (35)	21 (33)	3 (50)	0.416
Confusion	14 (20)	13 (21)	1 (17)
Delirium	7 (10)	6 (10)	1 (17)
Altered level of conscience	3 (4)	2 (3)	1 (17)
Neurological deficits§ (%)	9 (13)	6 (10)	3 (50)	0.006
Neurology consultation (%)	14 (20)	11 (17)	3 (50)	0.058
Speech-pathology consultation (swallow study) (%)	16 (23)	13 (21)	3 (50)	0.003
Normal (%)	9 (13)	9 (15)	0 (0)
Abnormal (%)	7 (10)	4 (6)	3 (50)
Hospital length of stay (med [P25–P75]) (days)	30 (21–46)	30 (21–46)	32 (21–127)	0.424
Discharge location (%)				<0.001
Home	58 (84)	55 (87)	3 (50)
Death	1 (1)	0 (0)	1 (17)
Other hospital	5 (7)	5 (8)	0 (0)
Rehab/long-term care	5 (7)	3 (5)	2 (33)
6-month mortality (%)	3 (4)	1 (2)	2 (33)	<0.001

Notes: EEG = electroencephalogram; CT = computerized tomography; MRI = magnetic resonance imaging; ICU = intensive care unit; MET = medical emergency team; MV = mechanical ventilation.

§Deficits included: focal neurologic deficits; seizure.

Table 4. Summary of preoperative acute physiology and laboratory values, divided according to before and after QA implementation.

Characteristic	Overall (n = 69)	Before QA Review (n = 30)	After QA Review (n = 39)	p-Value
MELD Score (mean [SD])	24.2 (8.5)	22.6 (8.4)	25.4 (8.5)	0.172
Temperature (mean [SD]) (degree Celsius)	35.9 (0.6)	36.2 (0.6)	35.8 (0.6)	0.012
Heart rate (mean [SD]) (/min)	82.0 (12.5)	81.1 (13.8)	82.7 (11.1)	0.593
Mean arterial pressure (mean [SD]) (mmHg)	83.7 (11.2)	82.1 (8.4)	85.0 (12.9)	0.290
CVP (mean [SD]) (mmHg)	12.2 (5.3)	11.6 (4.9)	12.7 (5.6)	0.381
Hemoglobin (mean [SD]) (g/L)	104 (18)	110 (20)	100 (17)	0.025
White cell count (med [P25–P75]) (10^9 cells/mL)	5.3 (4.3–7.6)	6.2 (4.5–9.2)	5.1 (3.9–6.3)	0.087
Platelets (mean [SD]) (10^9 cells/mL)	93 (76)	105 (75)	85 (77)	0.301
Bilirubin (med [P25-P75]) (µmol/L)	94 (47–306)	89 (53–372)	110 (35–288)	0.545
INR (mean [SD])	1.8 (0.6)	1.7 (0.5)	1.9 (0.8)	0.091
Albumin (mean [SD]) (µmol/L)	31.6 (7)	32.3 (8)	31.1 (6)	0.487
Sodium (SNa) (mean [SD]) (mmol/L)	129 (3)	129 (3)	128 (3)	0.643
Serum creatinine (mean [SD]) (µmol/L)	93 (49)	100 (46)	87 (52)	0.334
Pre-operative vasopressors (%)	3 (4)	1 (3)	2(5)	–
Pre-operative RRT (%)	10 (14)	3 (10)	7 (17)	0.352
Pre-operative corticosteroids (%)	6 (8)	4 (13)	2 (5)	0.230
Pre-operative diuretic therapy (%)	49 (71)	24 (80)	25 (64)	0.149

Notes: QA = quality assurance; SD = standard deviation; MELD = model for end-stage liver disease; ICU = intensive care unit; CVP = central venous pressure; INR = international normalized ratio; RRT = renal replacement therapy.

Table 5. Details of peri-operative serum sodium shift, and intra/post-operative treatments, divided according to before and after QA implementation.

Characteristic	Overall (n = 69)	Before QA review (n = 30)	After QA review (n = 39)	p-Value
Pre-operative sodium (SNa) (mean [SD]) (mmol/L)	129 (3)	129 (3)	128 (3)	0.643
Δ SNa at 24 h (mean [SD]) (mmol/L)	4.1 (3.9)	5.3 (4.8)	3.3 (2.8)	0.036
Post-operative SNa at 24 h (mean [SD]) (mmol/L)	133 (4)	134 (5)	132 (4)	0.135
Increase in SNa >10 mmol/L at 24 h (%)	6 (9)	6 (20)	0 (0)	0.003
Δ SNa at 48 h (mean [SD]) (mmol/L)	5.3 (3.8)	5.9 (4.3)	4.9 (3.4)	0.310
Post-operative SNa at 48 h (mean [SD]) (mmol/L)	134 (4)	135 (5)	134 (3)	0.509
Increase in SNa >10 mmol/L at 48 h (%)	8 (12)	5 (17)	3 (8)	0.248
Operative duration (mean [SD]) (min)	406 (142)	403 (184)	409 (102)	0.861
Intra-operative fluid balance (med [P25–P75]) (L)	5.6 (4.0–7.75)	6.4 (4.6–7.9)	5.2 (3.3–8.0)	0.020
Post-operative fluid balance at 24 h (med [P25–P75]) (L)	3.0 (1.2–5.2)	2.9 (0.8–5.6)	3.4 (1.6–4.8)	0.799
Post-operative fluid balance at 48 h (med [P25–P75]) (L)	2.8 (1.2–4.0)	2.7 (0.8–4.0)	3.0 (1.5–4.2)	0.934
Intra-operative CRRT (%)	11 (16)	5 (17)	6 (15)	0.885
Post-operative RRT (%)	12 (17)	4 (13.3)	8 (20)	0.435
Intra-operative vasopressors (%)
Any (%)	69 (100)	30 (100)	39 (100)	–
Vasopressin (%)	54 (78)	22 (73)	32 (82)	0.384
Post-operative vasopressors (%)
Any (%)	41 (59)	16 (53)	27 (69)	0.177
Vasopressin (%)	27 (39)	9 (30)	18(46)	0.173
Post-operative diuretics (%)	16 (23)	7 (23)	9 (23)	0.980

Notes: QA = quality assurance; SNa = serum sodium; SD = standard deviation; CRRT = continuous renal replacement therapy; RRT = renal replacement therapy.

Table 6. Summary of clinical outcomes, divided according to before and after QA implementation.

Characteristic	Overall (n = 69)	Before QA review (n = 30)	After QA review (n = 39)	p-Value
Duration of MV (med [P25–P75]) (days)	2 (1–3)	2 (1–4)	1 (1–3)	0.784
Re-intubation required (%)	16 (23)	5 (16)	11 (28)	0.236
Difficult to wean from mechanical ventilation (%)	14 (20)	4 (13)	10 (25)	0.208
Tracheostomy (%)	10 (14)	6 (20)	4 (10)	0.254
ICU length of stay (med [P25–P75]) (days)	4 (2–8)	4 (2–12)	4 (2–7)	0.651
MET activation (%)	15 (22)	5 (16)	10 (25)	0.370
ICU re-admission (%)	15 (22)	5 (16)	10 (25)	0.370
Brain CT (%)	16 (23)	9 (30)	7 (18)	0.240
Brain MRI (%)	15 (22)	5 (16)	10 (25)	0.370
EEG (%)	6 (9)	4 (13)	2 (5)	0.442
Abnormal mental status (%)	24 (35)	9 (30)	15 (38)	0.464
Confusion	14 (20)	7 (23)	7 (18)
Delirium	7 (10)	1 (3)	6 (15)
Altered level of conscience	3 (4)	1 (3)	2 (5)
Neurological deficits§ (%)	9 (13)	6 (20)	3 (8)	0.156
Neurology consultation (%)	14 (20)	9 (30)	5 (13)	0.079
Speech-pathology consultation (swallow study) (%)	16 (23)	8 (27)	8 (21)	0.261
Abnormal (%)	7 (10)	5 (17)	2 (5)
Hospital length of stay (med [P25–P75]) (days)	30 (21–46)	31 (23–50)	30 (17–43)	0.482
Discharge location (%)				0.125
Home	58 (84)	26 (86)	32 (82)
Death	1 (1)	1 (3)	0 (0)
Other hospital	5 (7)	0 (0)	5 (13)
Rehab/long-term care	5 (7)	3 (10)	2 (5)
6-month mortality (%)	3 (4)	3 (10)	0 (0)	0.043

Notes: QA = quality assurance; EEG = electroencephalogram; CT = computerized tomography; MRI = magnetic resonance imaging; ICU = intensive care unit; MET = medical emergency team; MV = mechanical ventilation.

§Deficits included: focal neurologic deficits; seizure.