Responses to experimental subarachnoid hemorrhage in the spontaneously breathing primate

1980 ◽  
Vol 52 (3) ◽  
pp. 302-308 ◽  
Author(s):  
Charles Rothberg ◽  
Bryce Weir ◽  
Thomas Overton ◽  
Michael Grace

✓ The pathophysiological responses to experimental subarachnoid hemorrhage (SAH) were investigated in 20 spontaneously breathing cynomolgus monkeys. Four different volumes of fresh autogenous blood were used: 1.0, 1.33, 1.67, and 2.0 cc/kg. Five other animals had injection of 1.67 cc/kg of mock cerebrospinal fluid. Cerebral blood flow (CBF) was measured using the xenon-133 clearance technique. Respiratory rate and tidal volume were monitored by way of a Vertek pneumotach. The reduction of CBF after the SAH became more pronounced with increasing volumes of subarachnoid blood. The CBF remained reduced despite a return to normal of the cerebral perfusion pressure. Increasing SAH volumes were associated with greater abnormalities in the respiratory pattern, consisting of apnea and hyperventilation. These larger volumes were also associated with hypoxemia. Morbidity and mortality increased with increasing volumes of SAH, and are believed to be the result of a combination of decreased CBF, respiratory center disturbances, and pulmonary diffusion defects.

1998 ◽  
Vol 88 (1) ◽  
pp. 28-37 ◽  
Author(s):  
Andreas Gruber ◽  
Andrea Reinprecht ◽  
Harald Görzer ◽  
Peter Fridrich ◽  
Thomas Czech ◽  
...  

Object. This observational study is based on a consecutive series of 207 patients with aneurysmal subarachnoid hemorrhage who were treated within 7 days of their most recent bleed. The purpose of the study was to evaluate the effect of respiratory failure on neurological outcome. Methods. Pulmonary function was assessed by determination of parameters describing pulmonary oxygen transport and exchange, by using composite scores for quantification of lung injury (lung injury score [LIS]) and mechanical ventilator settings (PIF score). Pulmonary function was related to the Hunt and Hess (H & H) grade assigned to the patient at hospital admission (p < 0.001). The pattern and time course of lung injury differed significantly between patients with H & H Grade I or II, Grade III, and Grade IV or V. Hunt and Hess grade, Fisher computerized tomography grade, intracranial pressure, cerebral perfusion pressure, LIS, ratio of PaO2 to the fraction of inspired oxygen (FiO2), and the ratio of the alveolar-minus-arterial oxygen tension difference (AaDO2) to FiO2 were related to neurological outcome (p < 0.001). The LIS on the day of maximum lung injury remained an independent predictor of outcome (p = 0.01) in a stepwise logistic regression analysis. The probability of poor neurological outcome significantly increased with both decreasing cerebral perfusion pressure and increasing severity of lung injury. Conclusions. The overall mortality rate was 22.2% (46 of 207 patients). Subarachnoid hemorrhage and its neurological sequelae accounted for the principal mortality in this series. Medical (nonneurological and nontreatment-related) complications accounted for 37% of all deaths. Systemic inflammatory response syndrome with associated multiple organ dysfunction syndrome was the leading cause of death from medical complications. The authors conclude that respiratory failure is related to neurological outcome, although it is not commonly the primary cause of death from medical complications.


1976 ◽  
Vol 45 (5) ◽  
pp. 498-507 ◽  
Author(s):  
Jack M. Fein

✓ Ischemia-provoking factors such as vasospasm, decreased cerebral perfusion pressure, and intravascular thrombosis may be present after subarachnoid hemorrhage (SAH). When these factors were not present during controlled SAH, a primary depression of cerebral glycolysis associated with normal stores of energy-rich phosphates was found. Although cerebral blood flow usually changes in response to changes in cerebral metabolic needs, this influence on the circulation was not evident in the early hours after SAH. After 3 to 4 hours an erratic decrease in blood flow occurred, probably related to vasospasm; and there were measurable decreases in energy-rich phosphates similar to those occurring after more severe and prolonged ischemias. These findings are indicative of abnormally erratic vascular responses to metabolic cues and may play a role in producing the encephalopathy of SAH.


2000 ◽  
Vol 92 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Niels Juul ◽  
Gabrielle F. Morris ◽  
Sharon B. Marshall ◽  
_ _ ◽  
Lawrence F. Marshall

Object. Recently, a renewed emphasis has been placed on managing severe head injury by elevating cerebral perfusion pressure (CPP), which is defined as the mean arterial pressure minus the intracranial pressure (ICP). Some authors have suggested that CPP is more important in influencing outcome than is intracranial hypertension, a hypothesis that this study was designed to investigate.Methods. The authors examined the relative contribution of these two parameters to outcome in a series of 427 patients prospectively studied in an international, multicenter, randomized, double-blind trial of the N-methyl-d-aspartate antagonist Selfotel. Mortality rates rose from 9.6% in 292 patients who had no clinically defined episodes of neurological deterioration to 56.4% in 117 patients who suffered one or more of these episodes; 18 patients were lost to follow up. Correspondingly, favorable outcome, defined as good or moderate on the Glasgow Outcome Scale at 6 months, fell from 67.8% in patients without neurological deterioration to 29.1% in those with neurological deterioration. In patients who had clinical evidence of neurological deterioration, the relative influence of ICP and CPP on outcome was assessed. The most powerful predictor of neurological worsening was the presence of intracranial hypertension (ICP ≥ 20 mm Hg) either initially or during neurological deterioration. There was no correlation with the CPP as long as the CPP was greater than 60 mm Hg.Conclusions. Treatment protocols for the management of severe head injury should emphasize the immediate reduction of raised ICP to less than 20 mm Hg if possible. A CPP greater than 60 mm Hg appears to have little influence on the outcome of patients with severe head injury.


2001 ◽  
Vol 95 (4) ◽  
pp. 569-572 ◽  
Author(s):  
Bon H. Verweij ◽  
J. Paul Muizelaar ◽  
Federico C. Vinas

Object. The poor prognosis for traumatic acute subdural hematoma (ASDH) might be due to underlying primary brain damage, ischemia, or both. Ischemia in ASDH is likely caused by increased intracranial pressure (ICP) leading to decreased cerebral perfusion pressure (CPP), but the degree to which these phenomena occur is unknown. The authors report data obtained before and during removal of ASDH in five cases. Methods. Five patients who underwent emergency evacuation of ASDH were monitored. In all patients, without delaying treatment, a separate surgical team (including the senior author) placed an ICP monitor and a jugular bulb catheter, and in two patients a laser Doppler probe was placed. The ICP prior to removing the bone flap in the five patients was 85, 85, 50, 59, and greater than 40 mm Hg, resulting in CPPs of 25, 3, 25, 56, and less than 50 mm Hg, respectively. Removing the bone flap as well as opening the dura and removing the blood clot produced a significant decrease in ICP and an increase in CPP. Jugular venous oxygen saturation (SjvO2) increased in four patients and decreased in the other during removal of the hematoma. Laser Doppler flow also increased, to 217% and 211% compared with preevacuation flow. Conclusions. Intracranial pressure is higher than previously suspected and CPP is very low in patients with ASDH. Removal of the bone flap yielded a significant reduction in ICP, which was further decreased by opening the dura and evacuating the hematoma. The SjvO2 as well as laser Doppler flow increased in all patients but one immediately after removal of the hematoma.


1996 ◽  
Vol 85 (5) ◽  
pp. 758-761 ◽  
Author(s):  
Julio Cruz

✓ Global cerebrovenous oxygenation was evaluated before and after intravenous administration of pentobarbital sodium for the management of refractory intracranial hypertension in 151 comatose patients who had acute traumatic brain swelling. Two groups of patients were identified: a group in which the jugular oxyhemoglobin saturation (SjO2) remained at or above 45% after pentobarbital bolus, and a group in which the SjO2 dropped below 45%. The two groups were matched by predominant findings on computerized tomography scans of the head, as well as age, postresuscitation Glasgow Coma Scale scores, levels of total hemoglobin content, SjO2, intracranial pressure (ICP), and cerebral perfusion pressure (CPP) prior to pentobarbital bolus. Outcomes were significantly worse (p < 0.0001) in patients who developed decreases in SjO2 to levels below 45% than in those whose SjO2 remained at or above 45%, despite the fact that there were no significant differences between the two groups with regard to ICP and CPP after an intravenous bolus of pentobarbital.


1975 ◽  
Vol 43 (3) ◽  
pp. 308-317 ◽  
Author(s):  
Lawrence F. Marshall ◽  
Felix Durity ◽  
Robert Lounsbury ◽  
David I. Graham ◽  
Frank Welsh ◽  
...  

✓ Cerebral blood flow, electrical activity, and neurological function were studied in rabbits subjected to either 15 minutes of oligemia (20 torr cerebral perfusion pressure) or complete cerebral ischemia produced by cisterna magna infusion. During oligemia, flow was reduced from 68.4 ± 4.2 ml/100 gm/min to 26.3 ± 4.4 (p < .01), and during ischemia animals had no proven flow. By 5 minutes after oligemia or ischemia significant symmetrical hyperemia occurred and there was no evidence of the no-reflow phenomenon. The electroencephalogram became isoelectric significantly later and returned significantly sooner in oligemia than in ischemia. Oligemic animals had earlier and better return of neurological function than their ischemic counterparts, although postinsult hypocapnia improved functional recovery in both groups. These experiments do not support the concept that oligemia is a more severe insult than complete ischemia. In intracranial hypertension produced by this model, the no-reflow phenomenon does not occur.


1982 ◽  
Vol 57 (5) ◽  
pp. 622-628 ◽  
Author(s):  
Mamoru Taneda

✓ The effect of removal of subarachnoid blood clots on the prevention of delayed ischemic deficit was evaluated in 239 consecutive patients with ruptured supratentorial non-giant aneurysms. All patients were hospitalized within 24 hours after subarachnoid hemorrhage (SAH) and were classified in Grades 1 to 4 according to the system of Hunt and Hess; classification was made immediately preoperatively in patients operated on within 48 hours after SAH, or 48 hours after SAH in patients for whom delayed operation was planned. Delayed ischemic deficit causing permanent disability or death occurred in 11 (25%) of 44 patients in whom surgery was planned to be delayed for 10 days or more, in 26 (27.7%) of 94 patients in whom the aneurysms were obliterated and blood clots adjacent to them were removed within 48 hours of SAH, and in 11 (10.9%) of 101 patients in whom the aneurysms were obliterated and extensive and aggressive removal of thick subarachnoid clots lying along the arteries (identified on computerized tomographic scan) was performed within 48 hours of SAH. Accordingly, early operation is an effective and reliable method to reduce the occurrence of severe delayed ischemic deficit only when subarachnoid blood clots are removed extensively and aggressively along the arteries within 48 hours of SAH.


1976 ◽  
Vol 44 (3) ◽  
pp. 337-341 ◽  
Author(s):  
James E. Raisis ◽  
Glenn W. Kindt ◽  
John E. McGillicuddy ◽  
Carole A. Miller

✓ Cerebral metabolism in 21 hydrocephalic patients was studied. Preoperative and postoperative specimens of cerebrospinal fluid (CSF) were obtained and the cerebral perfusion pressure (CPP) was calculated in each instance. The specimens of CSF were analyzed for lactate and pyruvate and the lactate/pyruvate (L/P) ratio was calculated for each sample. The L/P ratio, which reflects the redox state of the cell, was used to determine the extent of anaerobic metabolism. An inverse relationship was noted between CPP and lactate as well as the L/P ratio. In general, the level of anaerobic metabolism was decreased after insertion of a shunt.


1975 ◽  
Vol 42 (3) ◽  
pp. 282-289 ◽  
Author(s):  
Frank Matakas ◽  
Rainer v. Waechter ◽  
Reent Knüpling ◽  
Samuel J. Potolicchio

✓ Brain swelling was produced in monkeys and cats by the inflation of an epidural balloon against the parietal lobe. Resulting changes in intracranial pressure (ICP) were correlated to variation in systemic arterial pressure (SAP). Intracranial perfusion pressure (ICPP) defined as the difference between SAP and ICP, was found to vary with the degree of arterial hyper- and hypotension. The relationship between SAP and ICP can be explained by an existing equilibrium between extramural pressure and vessel wall circumferential tension. A positive perfusion pressure can exist in brain swelling as long as vessel wall tension is preserved and the degree of expanding brain tissue volume is held below certain limits.


1972 ◽  
Vol 37 (3) ◽  
pp. 316-324 ◽  
Author(s):  
K. C. Petruk ◽  
G. R. West ◽  
M. R. Marriott ◽  
J. W. McIntyre ◽  
T. R. Overtone ◽  
...  

✓ The acute effects of experimental subarachnoid hemorrhage on cerebral blood flow were investigated in 14 adult rhesus monkeys injected with fresh autogenous blood through a needle positioned within the subfrontal subarachnoid space. Cerebral blood flow was measured by the xenon133 tissue clearance method before hemorrhage, and afterward at 30-minute intervals for a 3-hour period. Post-anesthetic neurological status was graded according to Botterell's classification. Twelve monkeys showed a significant decrease in cerebral perfusion, eight displayed focal neurological deficits, and four were moribund. There was a correlation between the degree of impaired circulation and the severity of neurological deficit. Four additional monkeys subjected to subarachnoid acidic saline injection showed no reduction in cerebral blood flow. In three animals cerebral perfusion was increased during the first hour after injection. It is suggested that measurement of cerebral blood flow may be a more valuable prognostic indication of cerebral function and survival than the angiographic demonstration of arterial vasospasm.


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