Table 1.

Serum potassium of patients with normal serum potassium on admission when entered the operating room

Time	Serum potassium (mmol/L)	Paired sample	Difference and 95% CI (mmol/L)	Paired-t test
				t value	p value
After admission	3.9 ± 0.2	After admission- before skin incision	0.42(0.36 to 0.49)	12.45	< 0.001
Before skin incision	3.5 ± 0.3	After admission - before discharge	-0.08(-0.16 to 0.00)	-1.97	0.051
Before discharge	4.0 ± 0.4	Before skin incision - before discharge	-0.51(-0.59 to -0.43)	12.90	< 0.001