Analyses of cerebral microdialysis in patients with traumatic brain injury: relations to intracranial pressure, cerebral perfusion pressure and catheter placement

Table 2 Pooled microdialysis data and cerebral perfusion pressure^a

				CPP, mmHg
Pericontusional	< 40	40 to 50	50 to 60	60 to 70	70 to 80	80 to 90	> 90
Glucose, mM/l	0.5 ± 0.7	1.0 ± 1.2	1.5 ± 1.4	1.7 ± 1.4	2.0 ± 1.6	2.2 ± 1.6	2.1 ± 1.4
Lactate, mM/l	11 ± 6.3	5.0 ± 3.6	5.3 ± 2.6	5.3 ± 2.7	5.2 ± 2.6	5.0 ± 2.5	4.8 ± 2.8
Pyruvate, μM/l	253 ± 190	263 ± 348	147 ± 85	166 ± 83	171 ± 89	177 ± 85	178 ± 89
Glycerol, μM/l	307 ± 312	166 ± 213	258 ± 303	240 ± 374	262 ± 430	247 ± 377	315 ± 422
LP ratio	45 ± 20	55 ± 117	61 ± 105	46 ± 78	45 ± 74	36 ± 49	28 ± 14
LG ratio	105 ± 70	31 ± 43	15 ± 25	8.9 ± 19	5.6 ± 12	3.6 ± 3.4	4.6 ± 9.4
Number of samples (n 64 patients)	45	67	825	1,992	1,576	646	388
Nonpericontusional
Glucose, mM/l	1.2 ± 0.7	1.6 ± 0.9	2.0 ± 1.3	1.7 ± 1.4	1.7 ± 1.5	2.1 ± 1.6	2.6 ± 1.4
Lactate, mM/l	4.8 ± 1.1	4.1 ± 1.6	3.8 ± 2.1	4.1 ± 2.7	4.4 ± 2.9	4.1 ± 2.2	4.3 ± 1.5
Pyruvate, μM/l	162 ± 52	151 ± 58	155 ± 73	155 ± 61	161 ± 62	165 ± 58	188 ± 57
Glycerol, μM/l	309 ± 410	327 ± 513	356 ± 462	294 ± 415	190 ± 242	186 ± 213	144 ± 170
LP ratio	36 ± 25	28 ± 8.7	25 ± 14	28 ± 24	29 ± 24	25 ± 9.4	23 ± 7.1
LG ratio	5.2 ± 2.6	4.6 ± 6.4	4.5 ± 8.4	8.2 ± 19	9.6 ± 22	5.6 ± 11	3.7 ± 5.9
Number of patients (n 26 patients)	47	130	372	571	375	142	65

^aData are binned to levels of cerebral perfusion pressure (CPP), including the lactate:pyruvate (LP) and the lactate:glucose (LG) ratios, from 90 catheters (90 patients) in pericontusional and nonpericontusional locations. Data are expressed as means ± standard deviation (SD).

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