The influence of hyperthermia on intracranial pressure, cerebral oximetry and cerebral metabolism in traumatic brain injury

Figures & data

Figure 1. The occurrence of intracranial pressure (ICP) > 20 mmHg (in proportion of good monitoring time [GMT]) compared between periods in the highest temperature range (temperature ≥39 °C) and periods in the lower ranges (temperature <39 °C) for individual patients (25 patients with time in both temperature ranges). Each line with dots represents one patient.

Figure 2. Predicted values (and 95% CI) from a mixed model including intracranial pressure (ICP) (mmHg) as dependent variable. Upper panel, temperature (°C), compliance (amplitude > or ≤6 mmHg), and the interaction between temperature and compliance as independent variables. Lower panel, temperature (°C), pressure autoregulation (PRx > or ≤0.3) and the interaction between temperature and pressure autoregulation as independent variables.

Figure 3. Predicted values (and 95% CI) from a mixed model including B_tipO₂ (mmHg) as dependent variable and temperature (°C) as independent variable.

Figure 4. Predicted values (and 95% CI) from mixed models including energy metabolic microdialysis substances (glucose, lactate, pyruvate, and L/P ratio) as dependent variables and temperature (°C) as independent variable. L/P ratio = lactate/pyruvate ratio.

Table 1. The median relative occurrence (proportions of samples) for all individual patients in each microdialysis category (ischemia, metabolic crisis, hyperglycolysis, normal) by temperature. There were 1894 samples without hyperthermia in 28 patients and 661 with hyperthermia in 22 of the 28 patients.

	Temperature^a
	36 °C–37.9 °C	38 °C–42 °C
Microdialysis categories^b	Median occurrence^c % (IQR)	Median occurrence^c % (IQR)	P value
Ischemia	0 (0)	0 (0)	–
Metabolic crisis	0 (1)	0 (21)	0.42
Hyperglycolysis	34 (73)	26 (92)	0.65
Normal	55 (87)	44 (78)	0.63

^a Body temperature when microdialysis sample collected.

^b Ischemia: L/P ratio >40 and pyruvate <50; Metabolic crisis: L/P ratio >25 and pyruvate 50–120; Hyperglycolysis: L/P ratio <40, lactate >4, and pyruvate >120.

^c The relative occurrence of the microdialysis categories was calculated for each patient, and then the median relative occurrence for all patients was calculated.