Clinical applications of the pressure-volume index in treatment of pediatric head injuries

✓ The pressure-volume index (PVI) technique of assessing neural axis pressure-volume relationships was used as an adjunct to managing 22 children with severe head injuries and a Glasgow Coma Scale score of 8 or less. Ventricular cannulation was used to continuously monitor intracranial pressure (ICP). Actual PVI was measured by bolus injection of fluid and compared with predicted values determined from head circumference and spinal axis length in each patient. In 55% of the children, ICP was below 20 mm Hg at initial monitoring. During the course of monitoring, 86% of the children had ICP's exceeding 20 mm Hg. Reduced PVI (less than 80% of predicted normal) proved to be an accurate indicator of impending intracranial hypertension. The PVI proved to be a useful test for assessing the response to therapies for lowering ICP. This study demonstrates that reduced neural axis compliance accompanies intracranial hypertension following severe head injury in children, and that treatment of reduced neural axis compliance may prevent refractory intracranial hypertension.

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Effect of the skull and dura on neural axis pressure-volume relationships and CSF hydrodynamics

Journal of Neurosurgery ◽

10.3171/jns.1985.63.1.0076 ◽

1985 ◽

Vol 63 (1) ◽

pp. 76-81 ◽

Cited By ~ 40

Author(s):

Kenneth Shapiro ◽

Arno Fried ◽

Futoshi Takei ◽

Ira Kohn

Keyword(s):

Steady State ◽

Bolus Injection ◽

Venous Pressure ◽

Volume Index ◽

Constant Infusion ◽

Content Type ◽

Sagittal Sinus ◽

Neural Axis ◽

The Brain ◽

Fine Print

✓ The pressure-volume index (PVI) technique of bolus manipulation of cerebrospinal fluid (CSF) was used to measure changes of neural axis volume buffering-capacity and CSF dynamics produced by different conditions of the skull and dura. Twenty-eight cats were studied in the intact state, after bilateral craniectomy, and with the dura opened. At each stage of altering the container of the brain, the following parameters were obtained: steady-state intracranial pressure (ICP), sagittal sinus venous pressure, PVI, and the resistance to the absorption of CSF. The resistance to absorption of CSF was determined using both the bolus injection and the continuous infusion of fluid. After craniectomy, PVI increased from 0.76 ± 0.04 to 1.3 ± 0.07 ml (± standard error of the mean) (p < 0.001) and increased further to 3.6 ± 0.17 ml (p < 0.001) after opening the dura. The resistance to absorption of CSF (Ro), determined by bolus injection, decreased after craniectomy from 91.3 ± 7.5 to 56.3 ± 6.2 mm Hg/ml/min (p < 0.001) and decreased further to 8.9 ± 0.66 mm Hg/ml/min (p < 0.001) after opening the dura. Although resistance determined by constant infusion was similar, results were dependent on the rate of infusion. Despite these changes of resistance and PVI, steady-state ICP and sagittal sinus venous pressure were similar in all three conditions of the skull and dura. These studies indicate that changes of the container of the brain affect pressure-volume relationships within the neural axis. However, the changes of resistance to absorption of CSF are in a direction that preserves a steady-state hydrodynamic equilibrium.

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Effects of positive end-expiratory pressure on intracranial pressure and compliance in brain-injured patients

Journal of Neurosurgery ◽

10.3171/jns.1977.47.2.0195 ◽

1977 ◽

Vol 47 (2) ◽

pp. 195-200 ◽

Cited By ~ 71

Author(s):

Elizabeth A. M. Frost

Keyword(s):

Intracranial Pressure ◽

Brain Injuries ◽

Head Injuries ◽

Venous Pressure ◽

Neurological Status ◽

Volume Index ◽

Positive End Expiratory Pressure ◽

Content Type ◽

Intracranial Compliance ◽

Fine Print

✓ Hypoxic pulmonary disorders and head injuries associated with increased intracranial pressure (ICP) frequently co-exist. Positive end-expiratory pressure (PEEP) improves hypoxemia but has been reported to impede cerebral venous return, potentially causing a further increase in ICP. This study examined the effects of PEEP on ICP at different levels of brain compliance. Continuous ICP recordings were obtained after insertion of Scott cannulas to the lateral ventricles of seven comatose patients. Brain compliance was assessed by calculation of the pressure volume index. Patients were maintained in a 30° head-up position. Maintenance of PEEP to levels of 40 cm H2O pressure for as long as 18 hours did not increase ICP in patients with either normal or low intracranial compliance, and did not increase ICP in the absence of pulmonary disease. Central venous pressure and pulmonary artery wedge pressure increased proportionately as PEEP was increased. No consistent changes were found in blood pressure recordings, nor were there any reductions in cardiac output found during the studies. Abrupt discontinuation of PEEP did not result in increased ICP except for a transient rise on two occasions when respiratory secretions became copious and the patients were inadequately ventilated. Improved oxygenation in two patients as a result of PEEP was concomitant with improved intracranial compliance and neurological status. In patients with brain injuries, PEEP improves arterial oxygenation without increasing ICP as previously supposed. Consequently, PEEP is a valuable form of therapy for the comatose patient with pulmonary disorders such as pneumonia or pulmonary edema.

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The outcome with aggressive treatment in severe head injuries

Journal of Neurosurgery ◽

10.3171/jns.1979.50.1.0026 ◽

1979 ◽

Vol 50 (1) ◽

pp. 26-30 ◽

Cited By ~ 247

Author(s):

Lawrence F. Marshall ◽

Randall W. Smith ◽

Harvey M. Shapiro

Keyword(s):

Intracranial Hypertension ◽

Head Injuries ◽

High Rate ◽

High Dose ◽

Content Type ◽

Diffuse Brain Injury ◽

High Dose Dexamethasone ◽

Brain Injured ◽

Injured Patients ◽

Fine Print

✓ In a series of 100 consecutive patients with severe head injuries, uncontrolled intracranial hypertension, which was defined as occurring when intracranial pressure (ICP) exceeded 40 mm Hg for 15 minutes or more, occurred in 25 patients. This was despite high-dose dexamethasone, hyperventilation, mannitol, normothermia, appropriate surgical evacuation, and cerebrospinal fluid drainage when possible. Persistently elevated ICP occurred in 19 patients with diffuse brain injury, and in six patients uncontrolled intracranial hypertension followed evacuation of a surgical mass. All of these patients received intravenous barbiturates to control the ICP. At the time of initial barbiturate administration, 11 of the 25 had bilaterally unreactive pupils and 12 were decerebrate. The initial pentobarbital loading dose (3 to 5 mg/kg) effectively reduced the ICP in 76% of the patients. Prolonged pentobarbital treatment with blood barbiturate levels from 2.5 to 3.5 mg% was associated with normalization of the ICP (ICP less than 15 mm Hg) in 13 patients. In those patients responding to barbiturates, the daily mannitol requirement was reduced from 4.5 to 0.5 gm/kg/day (p < 0.01). In six nonresponders to barbiturates, mannitol requirements increased to 5.9 gm/kg/day; five of these died and one remains vegetative. Ten of the 19 barbiturate responders have returned to a productive life, two remain moderately disabled, two are severely disabled, one is vegetative, and four are dead. The high rate of good quality survival in this series of severely brain-injured patients indicates that barbiturates are useful in the treatment of uncontrolled intracranial hypertension and that a broader investigation of the clinical application of barbiturates is indicated.

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The oval pupil: clinical significance and relationship to intracranial hypertension

Journal of Neurosurgery ◽

10.3171/jns.1983.58.4.0566 ◽

1983 ◽

Vol 58 (4) ◽

pp. 566-568 ◽

Cited By ~ 65

Author(s):

Lawrence F. Marshall ◽

David Barba ◽

Belinda M. Toole ◽

Sharon A. Bowers

Keyword(s):

Intracranial Hypertension ◽

Head Injuries ◽

Transitional Stage ◽

Content Type ◽

Closed Head Injuries ◽

Transtentorial Herniation ◽

Neurosurgical Patients ◽

Closed Head ◽

Third Nerve ◽

Fine Print

✓ The oval pupil, or what has also been termed the “oblong” or “football” pupil, has been observed in 15 neurosurgical patients over a 2-year period. In 14 of the 15 patients, the intracranial pressure (ICP) was elevated, ranging from 18 to 38 mm Hg. While the oval pupil was primarily seen in patients suffering closed head injuries (11 cases), it was also observed in two patients with elevated ICP following hemorrhage from an arteriovenous malformation. In nine of the 14 patients in whom the pupillary abnormality was associated with intracranial hypertension, the oval pupil disappeared when the ICP was reduced to below 20 mm Hg. In four cases, the ICP could not be controlled and the pupil became progressively larger, and finally fixed and unreactive. The oval pupil represents a transitional stage indicating transtentorial herniation with third nerve compression. Although it may be seen in the absence of intracranial hypertension (one case in this series), this appears to be relatively uncommon. The presence of such a pupil on examination in a patient suffering an intracranial catastrophe, be it head injury, subarachnoid hemorrhage, or intracerebral hemorrhage, suggests impending transtentorial herniation with brain-stem compression.

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Diastematomyelia associated with teratomas

Journal of Neurosurgery ◽

10.3171/jns.1980.53.5.0720 ◽

1980 ◽

Vol 53 (5) ◽

pp. 720-725 ◽

Cited By ~ 43

Author(s):

Nancy Ugarte ◽

F. Gonzalez-Crussi ◽

C. Sotelo-Avila

Keyword(s):

Spinal Cord ◽

Content Type ◽

Spinal Cord Malformation ◽

Spinal Axis ◽

Neural Axis ◽

Fine Print

✓ Diastematomyelia, a complete or incomplete sagittal division of the neural axis into halves, is usually accompanied by a number of other malformations. However, true teratomas arising in dorsal juxtaposition to the spinal axis and associated with diastematomyelia are extremely rare. In this paper, two infants with this neoplastic-malformative complex are discussed. The two most prevalent hypotheses in the pathogenesis of diastematomyelia are reviewed. The hypothesis of a persistent neurenteric canal continues to be generally accepted, but, until more is known about the pathogenesis of extragonadal human teratomas, it is not possible to say how these neoplasms relate to the associated spinal cord malformation. Individually, each of the lesions present is extremely rare; it is possible that their concurrence in two patients may not be purely coincidental.

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Pressure-volume conditions in patients with subarachnoid and/or intraventricular hemorrhage

Journal of Neurosurgery ◽

10.3171/jns.1985.63.3.0398 ◽

1985 ◽

Vol 63 (3) ◽

pp. 398-403 ◽

Cited By ~ 22

Author(s):

Michael Kosteljanetz

Keyword(s):

Intracranial Pressure ◽

Blood Volume ◽

Intraventricular Hemorrhage ◽

Bolus Injection ◽

Pulse Amplitude ◽

Volume Index ◽

Icp Monitoring ◽

Content Type ◽

The Relationship ◽

Fine Print

✓ Pressure-volume conditions were studied in 17 patients with subarachnoid and/or intraventricular hemorrhage, who underwent continuous intracranial pressure (ICP) monitoring. The pressure-volume index (PVI) technique was used. The interrelationship between the ICP pulse amplitude and compliance was also examined. All patients were admitted in Hunt and Hess Grades II to V, and 11 had a proven aneurysm. The ICP was above 15 mm Hg in all patients during some part of the monitoring period. The pressure-volume conditions were abnormal in all patients. Median PVI was 12.7 ml (5.8 to 40.0 ml). The PVI did not correlate with ICP; the PVI based on bolus injection was significantly greater than PVI based on fluid withdrawal. The ICP pulse amplitude varied from 1.5 to 15 mm Hg and rose concomitantly with increasing ICP. Considering the pulsatile shift in intracranial blood volume as an endogenous bolus that increases ICP from the diastolic (Pdiast) to the systolic (Psyst) level, an equation was derived from the PVI model that describes the relationship between the Psyst:Pdiast ratio and the PVI.

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Pressure-volume relationships in shunt-dependent childhood hydrocephalus

Journal of Neurosurgery ◽

10.3171/jns.1986.64.3.0390 ◽

1986 ◽

Vol 64 (3) ◽

pp. 390-396 ◽

Cited By ~ 37

Author(s):

Kenneth Shapiro ◽

Arno Fried

Keyword(s):

Normal Pressure ◽

Buffering Capacity ◽

Volume Index ◽

Content Type ◽

Proximate Cause ◽

Volume Curve ◽

Pressure Volume Curve ◽

Neural Axis ◽

The Mean ◽

Fine Print

✓ The pressure-volume index (PVI) technique of bolus manipulation of cerebrospinal fluid (CSF) was used to measure neural axis volume buffering capacity and resistance to absorption of CSF (Ro) in 20 shunt-dependent hydrocephalic children acutely ill from shunt malfunction. All children had had ventricles that were near normal or subnormal in size when the shunts were functioning. The mean intracranial pressure (ICP, ± standard deviation (SD)) at the time of revision was 10.6 ± 6.4 mm Hg. The mean measured PVI (± standard error of the mean) was 18.4 ± 1.1 ml compared to the normal PVI of 17.5 ± 4.4 ml (± SD) predicted for these children. According to paired t-tests, these measured values were similar to those predicted on the basis of neural axis volume for each child, indicating that these children had normal neural axis volume buffering capacity. While the study was in progress, abrupt increases of ICP were documented in all children. These waves were observed spontaneously as well as in response to the addition of volume to the neural axis. In each child a specific threshold pressure along the pressure-volume curve corresponded to the appearance of unstable ICP. The threshold pressures at which this occurred corresponded to a mean neural axis compliance of 0.32 ± 0.07 ml/mm Hg (± SD). The Ro varied as a function of ICP. The Ro measured at ICP's below 15 mm Hg ranged from 2 to 7.5 mm Hg/ml/min and rose to 12 to 30 mm Hg/ml/min at pressures in the 20 to 25 mm Hg range. The results of this study indicate that neural axis volume buffering capacity is normal in shunt-dependent children who respond to shunting by reconstitution of the cortical mantle. This study indicates that the proximate cause of their abrupt clinical deterioration is unstable ICP, which occurred at a similar point on the pressure-volume curve of all children studied. The correlation of Ro to ICP suggests that CSF absorption does not increase in these children as ICP rises, resulting in movement along relatively normal pressure-volume curves. The functional implications of these parameters are discussed.

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CSF dynamics and pressure-volume relationships in communicating hydrocephalus

Journal of Neurosurgery ◽

10.3171/jns.1986.64.1.0045 ◽

1986 ◽

Vol 64 (1) ◽

pp. 45-52 ◽

Cited By ~ 33

Author(s):

Michael Kosteljanetz

Keyword(s):

Cerebrospinal Fluid ◽

Bolus Injection ◽

Formation Rate ◽

Cerebral Atrophy ◽

Pulse Amplitude ◽

Volume Index ◽

Communicating Hydrocephalus ◽

Csf Dynamics ◽

Content Type ◽

Normal Individuals

✓ Twenty-nine patients consecutively admitted with a diagnosis of communicating hydrocephalus underwent 1) continuous intracranial pressure (ICP) monitoring; 2) pressure-volume studies; and 3) measurement of resistance to outflow of cerebrospinal fluid (Rout). The two latter calculations were made by the bolus injection and pressure-volume index (PVI) techniques. In 19 patients mean ICP never exceeded 15 mm Hg. In the other 10 patients varying degrees of mildly raised ICP was noted. The frequency of waves at ½ to 2/min varied from 3% to 58%. The ICP pulse amplitude ranged from 0.5 to 10 mm Hg, and PVI from 4.6 to 18.2 ml. The Rout ranged from 2.5 to 31.4 mm Hg/ml/min, and was linearly correlated to the ICP. Thus, patients with a higher Rout also had a higher ICP as compared with patients with lower Rout, yet ICP could still be within limits considered normal. The cerebrospinal fluid dynamics (formation rate × resistance) contributed much more to the ICP than in normal individuals. It is postulated that communicating hydrocephalus represents one endpoint of a continuum, where the preceding phase is high-pressure and high-resistance hydrocephalus as, for instance, is seen after subarachnoid hemorrhage. In some patients, there is a possibility of cerebral atrophy accompanied by otherwise insignificant increased Rout. In this study, the PVI technique proved to be a fast and safe method of measuring Rout.

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The outcome with aggressive treatment in severe head injuries

Journal of Neurosurgery ◽

10.3171/jns.1979.50.1.0020 ◽

1979 ◽

Vol 50 (1) ◽

pp. 20-25 ◽

Cited By ~ 377

Author(s):

Lawrence F. Marshall ◽

Randall W. Smith ◽

Harvey M. Shapiro

Keyword(s):

Intracranial Hypertension ◽

Vegetative State ◽

Head Injuries ◽

Persistent Vegetative State ◽

Systemic Arterial Pressure ◽

High Dose ◽

Good Recovery ◽

Content Type ◽

Successful Control ◽

Uniform Manner

✓ The authors have analyzed the hospital course and outcome in 100 consecutive patients with severe head injuries who either on admission or within 24 to 48 hours of their hospitalization were not verbally responsive, and not able to follow commands. All were treated in a uniform manner. Operative intervention was performed immediately in patients with significant extracerebral hematomas or large superficial intracerebral hematomas. Intracranial pressure (ICP) was monitored in all, and in 55 patients treatment with a combination of dexamethasone, hyperventilation (PaCO2 of 25 to 28 mm Hg), mannitol, normothermia, and controlled systemic arterial pressure was required for intracranial hypertension (ICP > 15 mm Hg). In 25 patients whose ICP remained significantly elevated (ICP > 40 mm Hg for 15 minutes or more), high-dose pentobarbital therapy was used to lower the ICP. Forty-five patients recovered with no or minimal neurological deficit, and returned to their pre-injury occupation (good recovery). Fifteen patients are moderately disabled, four are severely disabled, and eight remain in a persistent vegetative state. The mortality rate was 28%. The favorable outcome in this series suggests that early aggressive surgical treatment, successful control of intracranial hypertension, and careful attention to medical complications can improve the outcome in patients with severe head injuries.

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