<p>Traumatic brain injury (TBI) renders the brain more vulnerable to secondary insults. The increased vulnerability can probably be explained by a combination of disturbances in hemodynamics, metabolism and craniospinal dynamics. Reduced ability to compensate for added intracranial volume, i.e. reduced intracranial compliance (IC), is one possible mechanism. The <i>aim</i> of this thesis was to study the role of IC on the effect of secondary insults after TBI. </p><p>A rat TBI model was developed where IC could be altered without causing pathological increases in intracranial pressure (ICP). Reduction of IC was made by placing rubber film between the dura mater and bilateral bone flaps. A reduction of IC in terms of reduced Pressure Volume Index was confirmed. Microdialysis (MD) of extracellular fluid was used to monitor neurochemical changes. Reduced IC after TBI proved to increase the vulnerability of the brain to secondary intracranial volume insults according to neurochemical microdialysis markers. Reduced IC or intracranial volume insults alone did not cause any metabolic changes as compared to controls. Moderate posttraumatic hypotension (50mmHg for 30 min) induced 2 hrs after TBI, did not aggravate posttraumatic extracellular neurochemical changes significantly, irrespective of the level of IC. Although controversial, a mild to moderate hypotensive insult after initial posttraumatic stabilization may not be as detrimental as earlier believed.</p><p>The Spiegelberg Compliance Monitor and MD were simultaneously used in 10 TBI patients to get an impression of the clinical value of IC monitoring and the relationship between IC, temperature and MD Lactate/Pyruvate ratio. IC and MD could be monitored simultaneously in TBI patients. Higher L/P ratios were seen when IC was low. Patients with induced coma treatment had significantly higher average L/P ratios, possibly due to their poorer neurological condition. An indication was also found that in TBI patients with high temperatures, L/P ratio rose as IC decreased, but in patients with low temperature there was no effect of IC on L/P ratio. These data suggest the importance of avoiding hyperthermia in TBI patients, especially in patients with low or decreased IC (monitored or anticipated).</p>

Traumatic brain injury (TBI) renders the brain more vulnerable to secondary insults. The increased vulnerability can probably be explained by a combination of disturbances in hemodynamics, metabolism and craniospinal dynamics. Reduced ability to compensate for added intracranial volume, i.e. reduced intracranial compliance (IC), is one possible mechanism. The aim of this thesis was to study the role of IC on the effect of secondary insults after TBI. A rat TBI model was developed where IC could be altered without causing pathological increases in intracranial pressure (ICP). Reduction of IC was made by placing rubber film between the dura mater and bilateral bone flaps. A reduction of IC in terms of reduced Pressure Volume Index was confirmed. Microdialysis (MD) of extracellular fluid was used to monitor neurochemical changes. Reduced IC after TBI proved to increase the vulnerability of the brain to secondary intracranial volume insults according to neurochemical microdialysis markers. Reduced IC or intracranial volume insults alone did not cause any metabolic changes as compared to controls. Moderate posttraumatic hypotension (50mmHg for 30 min) induced 2 hrs after TBI, did not aggravate posttraumatic extracellular neurochemical changes significantly, irrespective of the level of IC. Although controversial, a mild to moderate hypotensive insult after initial posttraumatic stabilization may not be as detrimental as earlier believed. The Spiegelberg Compliance Monitor and MD were simultaneously used in 10 TBI patients to get an impression of the clinical value of IC monitoring and the relationship between IC, temperature and MD Lactate/Pyruvate ratio. IC and MD could be monitored simultaneously in TBI patients. Higher L/P ratios were seen when IC was low. Patients with induced coma treatment had significantly higher average L/P ratios, possibly due to their poorer neurological condition. An indication was also found that in TBI patients with high temperatures, L/P ratio rose as IC decreased, but in patients with low temperature there was no effect of IC on L/P ratio. These data suggest the importance of avoiding hyperthermia in TBI patients, especially in patients with low or decreased IC (monitored or anticipated).

<p>Traumatic brain injury (TBI) is a major cause of death and disability. Intracranial secondary insults (e.g. intracranial haematoma, brain oedema) and systemic secondary insults (e.g. hypotension, hypoxaemia, hyperthermia) lead to secondary brain injury and affect outcome adversely. In order to minimise secondary insults and to improve outcome in TBI-patients, a secondary insult program and standardised neurointensive care (NIC) was implemented. The aim of this thesis was to describe patient outcome and to explore the occurrence and prognostic value of secondary insults after the implementation.</p><p>Favourable outcome was achieved in 79% and 6% died of the 154 adult TBI patients treated in the NIC unit 1996-97. In an earlier patient series from the department, 48% made a favourable outcome and 31% died. Hence, the outcome seems to have improved when NIC was standardised and dedicated to avoiding secondary insults. </p><p>Secondary insults counted manually from hourly recordings on surveillance charts did not hold any independent prognostic information. When utilising a computerised system, which enables minute-by-minute data collection, the proportion of monitoring time with systolic blood pressure > 160 mm Hg decreased the odds of favourable outcome independent of admission variables (odds ratio 0.66). Hyperthermia was related to unfavourable outcome. Hypertension was correlated to hyperthermia and may be a part of a hyperdynamic state aggravating brain oedema. </p><p>Increased proportion of monitoring time with cerebral perfusion pressure (CPP) < 60 mm Hg increased the odds of favourable outcome (odds ratio 1.59) in patients treated according to an intracranial pressure (ICP)-oriented protocol (Uppsala). In patients given a CPP-oriented treatment (Edinburgh), CPP <60 mm Hg was coupled to an unfavourable outcome. It was shown that pressure passive patients seem to benefit from an ICP-oriented protocol and pressure active patients from a CPP-oriented protocol. The overall outcome would improve if patients were given a treatment fit for their condition.</p>

Traumatic brain injury (TBI) is a major cause of death and disability. Intracranial secondary insults (e.g. intracranial haematoma, brain oedema) and systemic secondary insults (e.g. hypotension, hypoxaemia, hyperthermia) lead to secondary brain injury and affect outcome adversely. In order to minimise secondary insults and to improve outcome in TBI-patients, a secondary insult program and standardised neurointensive care (NIC) was implemented. The aim of this thesis was to describe patient outcome and to explore the occurrence and prognostic value of secondary insults after the implementation. Favourable outcome was achieved in 79% and 6% died of the 154 adult TBI patients treated in the NIC unit 1996-97. In an earlier patient series from the department, 48% made a favourable outcome and 31% died. Hence, the outcome seems to have improved when NIC was standardised and dedicated to avoiding secondary insults. Secondary insults counted manually from hourly recordings on surveillance charts did not hold any independent prognostic information. When utilising a computerised system, which enables minute-by-minute data collection, the proportion of monitoring time with systolic blood pressure &gt; 160 mm Hg decreased the odds of favourable outcome independent of admission variables (odds ratio 0.66). Hyperthermia was related to unfavourable outcome. Hypertension was correlated to hyperthermia and may be a part of a hyperdynamic state aggravating brain oedema. Increased proportion of monitoring time with cerebral perfusion pressure (CPP) &lt; 60 mm Hg increased the odds of favourable outcome (odds ratio 1.59) in patients treated according to an intracranial pressure (ICP)-oriented protocol (Uppsala). In patients given a CPP-oriented treatment (Edinburgh), CPP &lt;60 mm Hg was coupled to an unfavourable outcome. It was shown that pressure passive patients seem to benefit from an ICP-oriented protocol and pressure active patients from a CPP-oriented protocol. The overall outcome would improve if patients were given a treatment fit for their condition.