Table 3

 Response of urinary sodium, potassium, tonicity (Na + K), and osmolality to either N/2 or NS, according to whether the children were hyponatraemic or normonatraemic at T0 in the 36 children in whom a baseline urine sample (Ubase) was collected within 2 hours of T0, and a second sample (U2nd) was collected a median of 4.8 hours (range 3–12) after T0

Hyponatraemic at T0Normonatraemic at T0
N/2 (n = 8)NS (n = 8)N/2 (n = 9)NS (n = 11)
UbaseU2ndp valueUbaseU2ndp valueUbaseU2ndp valueUbaseU2ndp value
Results are expressed as median (range).
The p values refer to the comparison by Kruskall Wallis test of U2nd with Ubase.
Na (mmol/l)72 (<10–204)23 (<10–82)0.0938 (<10–109)16 (<10–75)0.0480 (16–124)59 (10–123)0.4479 (17–209)125 (19–294)0.01
K (mmol/l)70 (12–91)23 (4–38)0.0258 (19–88)24 (6–65)0.02105 (57–171)47 (10–74)0.008107 (42–232)39 (3–94)0.003
Tonicity (mmol/l)151 (19–285)45 (11–109)0.02106 (26–175)40 (14–140)0.02178 (146–213)104 (67–170)0.008183 (59–300)165 (46–322)0.63
Osmolality (mOsm/kg)976 (332–1290)506 (110–944)0.02935 (574–1072)768 (339–1059)0.021036 (856–1239)668 (284–1139)0.0081076 (707–1200)881 (317–1177)0.006