Microangiographic changes in the traumatized brain

Microangiographic changes following cerebral contusion in rats

The purpose of this study was to investigate the acute changes due to cerebral contusion in the large vessels and microvasculature in the rat. Thirty adult Sprague-Dawley rats underwent craniectomy performed in the left parietal region, producing a burr hole approximately 8-12 mm in diameter. The dura was left intact and a solid glass rod with a base diameter of 6 mm and weighing 5.2 g was dropped on the brain. Silicone rubber perfusion was performed at 24 h (10 rats) and 48 h (10 rats). Ten rats served as normal controls. The perfused brains were cleared using the alcohol-methylsalicylate technique. The results showed that the arterial and venous systems were clearly visualized by silicone rubber microangiography in the normal rat. Silicone rubber microangiography provided an excellent three-dimensional method for defining the distribution of the vasculature of the normal and contusioned rat brain, and was helpful in elucidating the pathophysiology of post-traumatic ischemia and hemorrhages of the brain. The brain displayed marked ischemia and hemorrhage at the contusion site. The hemorrhages were distributed throughout regions of white and gray matter at the injury site. All contusioned animals of those superficial arteries were irregularly filled or unfilled. The present study suggests that the pathogenesis of the post-traumatic brain may be related to damage of the superficial arteries and their arterial branches. Comparison of the brains from animals killed at 24 and 48 h following contusion revealed that the contusion was more severe 24 h after the vascular damage than after 48 h. Therefore, in the brains that were killed at 48 h, the contusion site was less avascular than those at the earlier times.

Impact of traumatic subarachnoid hemorrhage on outcome in nonpenetrating head injury. Part II: Relationship to clinical course and outcome variables during acute hospitalization

Patients with a nonpenetrating head injury and traumatic subarachnoid hemorrhage (tSAH) on admission head computed tomography scan (n = 240) were compared with patients without tSAH matched in terms of admission postresuscitation Glasgow Coma Scale (GCS) values, age, sex, and the presence of one or more types of intracranial mass lesions. Admission Injury Severity Score was higher only in tSAH patients with admission GCS scores between 13 and 15; GCS values at 6, 24, and 48 hours were lower for tSAH patients. Patients with tSAH underwent fewer craniotomies, but more than twice as many tSAH patients had high intracranial pressure at the time of ventriculostomy placement and 6 hours after admission. tSAH patients underwent more chest procedures and their incidence of hypoxia and hypotension was greater. tSAH patients spent more days in intensive care unit, more total days hospitalized, and had worse Glasgow Outcome Scale scores at acute hospital discharge. Fewer tSAH patients were discharged home, and almost 1.5 times as many tSAH patients died during hospitalization. Given a similar overall degree of injury at admission, patients with tSAH associated with a nonpenetrating head injury had a worse outcome than similar patients without tSAH.

The significance of subarachnoid hemorrhage after penetrating craniocerebral injury: correlations with angiography and outcome in a civilian population

Certain clinical factors are considered to have an effect on patient outcome after penetrating missile injury. These include bilateral hemispheric injury, ventricular hemorrhage, intracerebral hemorrhage, mass effect, and missile or bony fragmentation. The relationship of subarachnoid hemorrhage (SAH) after penetrating craniocerebral injury and outcome is unknown. In addition, controversy exists regarding the role of angiography and the incidence of traumatic intracranial aneurysm in this population. Finally, can we assume that the incidence of traumatic intracranial aneurysm is equal in military and civilian populations, given the absence of penetrating shrapnel injury in civilian populations? Now that computed tomography has supplanted angiography as the primary diagnostic modality, increasing vigilance on the part of the physician and examination of angiography in high-risk patients should allow for enhanced outcome. We evaluated 100 patients with a diagnosis of cerebral gunshot wound over a 12-month period. All patients were evaluated neurologically at the time of admission and had imaging studies. Thirty-one patients with radiological evidence of SAH on computed tomography underwent angiography. Angiograms were limited to the side of the injury in patients with single-lobe or unilateral multilobe injuries and were bilateral in patients with bilateral hemispheric involvement. One intracranial aneurysm (3.2%) was documented and treated surgically. In those patients who died within 48 hours of admission, 68% had SAH as compared with only 17% of those surviving. Outcome was based upon neurological evaluation at the time of discharge and at the time of clinical follow-up at 3 and 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Initial CT findings in 753 patients with severe head injury. A report from the NIH Traumatic Coma Data Bank

In this prospective multicenter study, the authors have examined data derived from the initial computerized tomography (CT) scans of 753 patients with severe head injury. When the CT findings were related to abnormal intracranial pressure and to death, the most important characteristics of the scans were: midline shift: compression or obliteration of the mesencephalic cisterns: and the presence of subarachnoid blood. Diffuse hemispheric swelling was also found to be associated with an early episode of either hypoxia or hypotension.

Experimental head injury in the rat. Part 3: Cerebral blood flow and oxygen consumption after concussive impact acceleration

Cerebral blood flow (CBF) and oxygen consumption (CMRO2) were determined during timmediate posttraumatic period in rats subjected to concussive impact acceleration. According to previous studies an impact of 9 m/sec velocity elicited typical and marked symptoms of experimental concussion and often a prolonged comatose state, accompanied by cerebral metabolic signs of energy failure. During the immediate concussive response there was an increase of the CBF, followed within the next few minutes by a decrease to about one-third of normal flow, and then by a tendency toward normalization of flow 20 to 40 minutes posttrauma. Simultaneous measurements of cerebral oxygen extraction indicated an increase of the CMRO2 during the first minute. During the ischemic phase oxygen extraction increased but the lowest CBF values were only partially compensated for, and normal oxygen availability could not be maintained. The combined data, including cerebrospinal fluid pressure measurements, indicated primary cerebrovascular effects of the concussive trauma. These vasomotor effects may induce critical cerebral ischemia and thus profoundly influence posttraumatic cerebral function, and cause irreversible damage.