Table 2

Arterial blood gas results as recorded in the national audit for the three acidotic patient subgroups

		All cases on admission		ACIDOTIC on admission, this being the lowest pH (group 1)		ACIDOTIC on admission, later lowest pH ALSO ACIDOTIC (group 2)				NON-ACIDOTIC on admission, later lowest pH ACIDOTIC (group 3)
		All cases on admission		ACIDOTIC on admission, this being the lowest pH (group 1)		On admission		Later		On admission		Later
pH			N=8215		N=1225		N=453		N=453		N=465		N=465
	<7.26	7%	557	35%	427	29%	130	60%	272	–	0	32%	151
	7.26–7.34	14%	1121	65%	798	71%	323	40%	181	–	0	68%	314
	7.35+	80%	6537	–	0	–	0	–	0	100%	465	–	0
	Median (IQR)	7.41 (7.36–7.45)		7.29 (7.22–7.32)		7.30 (7.25–7.32)		7.24 (7.18–7.27)		7.39 (7.36–7.41)		7.29 (7.23–7.32)
Bic			N=7826		N=1144		N=438		N=432		N=452		N=445
	<23	14%	1096	16%	187	14%	61	17%	73	11%	48	23%	101
	23–30	65%	5104	51%	584	44%	191	39%	168	57%	256	46%	204
	>30	21%	1626	33%	373	42%	186	44%	191	33%	148	31%	140
	Median (IQR)	26 (24–30)		28 (24–32)		29 (25–34)		29 (24–35)		28 (25–32)		27 (23–32)
PCO₂			N=8229		N=1197		N=453		N=452		N=462		N=465
	≤6.0	56%	4628	9%	107	5%	24	4%	16	39%	182	11%	49
	>6.0	44%	3601	91%	1090	95%	429	96%	436	61%	280	89%	416
	Median (IQR)	5.8 (4.9–7.2)		8.8 (7.3–10.9)		9.0 (7.6–10.5)		10.3 (8.7–12.4)		6.5 (5.4–7.6)		8.7 (7.3–10.1)
PO₂			N=8231		N=1200		N=453		N=450		N=462		N=463
	<7.3	21%	1691	19%	230	35%	158	24%	109	38%	176	24%	113
	7.3–8.0	14%	1125	7%	87	9%	41	9%	39	13%	60	10%	47
	>8.0	66%	5415	74%	883	56%	254	67%	302	49%	226	65%	303
	Median (IQR)	8.9 (7.6–11.3)		10.4 (7.9–14.8)		8.6 (6.5–11.9)		9.3 (7.5–12.5)		8.0 (6.6–9.7)		9.1 (7.3–11.5)