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At least 37 records · Page 2Linked to original sources
PubMed1992

Alfentanil increases intracranial pressure when intracranial compliance is low.

Intracranial pressure increases following the administration of alfentanil 1 mg are reported in five patients with suspected normal pressure hydrocephalus who were undergoing infusion of saline into a lateral ventricle to measure cerebrospinal fluid outflow resistance. The increase in intracranial pressure was accompanied by a fall in mean arterial pressure. These observations show that, when the intracranial compliance is reduced, alfentanil can cause considerable increases in intracranial pressure and decreases in cerebral perfusion pressure.

Aged↗
PubMed1983

Influence of urapidil on intracranial pressure and intracranial compliance in dogs.

During induced hypotension with urapidil, measurements of intracranial pressure and of the ventricular volume-pressure response (intracranial compliance) were obtained in dogs with and without intracranial hypertension. A bolus of urapidil 50 mg plus an infusion of urapidil 8.2 +/- 1.2 mg min-1 decreased mean arterial pressure by 22 +/- 10% from control in group I (without intracranial hypertension) and by 24 +/- 8% in group II (with intracranial hypertension). In both groups there was no change in intracranial pressure or in intracranial compliance after the administration of urapidil.

Animals↗
PubMed1999

[What kind of monitoring of intracranial pressure].

Intracranial pressure monitoring is an essential element of severe head injury monitoring. In the Italian reality, this monitoring still has not become diffusely utilised. In this paper are analysed, using the available data obtained from the Neurolink database, the information from the more advanced Italian neurotrauma centres. Only 50% of the patients, in which monitoring is indicated, are monitored. Synthetically will be reviewed the indications to the monitoring, the advantages offers from such procedure, the modalities of monitoring considering also the economic impact and the risks legacies to the procedure.

Craniocerebral Trauma↗
PubMed2004

The effects of craniosynostosis on the brain with respect to intracranial pressure.

Intracranial pressure (ICP) and skull volume are intricately related. Craniosynostosis alters skull volume, and the many forms of craniosynostosis complicate the relationship to ICP even further. Patients with single-suture synostosis are less likely to experience elevated ICP than patients in whom multiple sutures, craniofacial syndromes, or both are involved. Among patients with more than one suture involved, the multifactorial mechanisms underlying elevated ICP include cephalocranial disproportion and venous outflow obstruction. Direct monitoring of ICP for at least 24 hours can aid in the diagnosis and decision making process. The management of craniosynostotic patients is diverse and necessitates a long-term plan for follow-up.

Brain↗
PubMedDate not supplied

Moving the patient in bed: effects on intracranial pressure.

Intracranial pressure (ICP) was measured in 20 patients before and after each of eight nursing care activities: turning the body to four positions, passive range of motion (arm extension and hip flexion), and rotation of the head to the right and to the left. Technically usable data was available for 18 patients. Mean ICP increased for at least five minutes in all patients after one of the four turns and in 88 percent after half the turns. Change in mean ICP with one of a pair of lateral or supine turns was strongly predictive of the direction of change (increase or decrease) of the other turn of the pair. Large increases in ICP occurred in the five patients for whom head rotation was done, while there was minimal change in ICP with both passive range of motion procedures. A cumulative increase in ICP occurred with activities spaced 15 minutes apart, regardless of the nature of the activity. No cumulative increase in ICP was found with procedures spaced at least one hour apart.

Adult↗
PubMed2002

Effects of positive end-expiratory pressure on intracranial pressure and cerebral perfusion pressure.

The effect of positive end-expiratory pressure (PEEP) on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) has been reported by several investigators, without any consensus being reached. Acute neurological and neurosurgical patients suffer intracranial hypertension and acute lung injury with hypoxemia. Since PEEP may improve hypoxemia but elevate ICP and decrease CPP, it is important to determine the influence of varying levels of PEEP on ICP and CPP. The aim of the study was to investigate the changes in ICP and CPP associated with different levels of PEEP. Twenty patients requiring ICP monitoring and mechanical ventilation were enrolled. Patients had severe head injury (n = 10), spontaneous intracerebral haemorrhage (n = 5), and subarachnoid haemorrhage (n = 5). PEEP was raised from 5 (basal) to 15 cm H2O in steps of 5 cm H2O. After at least 10 minutes of each new PEEP setting, ICP and CPP were measured. PEEP at 10 and 15 cm H2O produced a significant (p < 0.05) increase in intracranial pressure 11.6 +/- 5.6 and 14.6 +/- 6.28 mm Hg, respectively; no significant (p = 0.819) change occurred in CPP.

Adult↗
PubMed2004

Monitoring and interpretation of intracranial pressure.

Intracranial pressure (ICP) is derived from cerebral blood and cerebrospinal fluid (CSF) circulatory dynamics and can be affected in the course of many diseases of the central nervous system. Monitoring of ICP requires an invasive transducer, although some attempts have been made to measure it non-invasively. Because of its dynamic nature, instant CSF pressure measurement using the height of a fluid column via lumbar puncture may be misleading. An averaging over 30 minutes should be the minimum, with a period of overnight monitoring in conscious patients providing the optimal standard. Computer-aided recording with online waveform analysis of ICP is very helpful. Although there is no "Class I" evidence, ICP monitoring is useful, if not essential, in head injury, poor grade subarachnoid haemorrhage, stroke, intracerebral haematoma, meningitis, acute liver failure, hydrocephalus, benign intracranial hypertension, craniosynostosis etc. Information which can be derived from ICP and its waveforms includes cerebral perfusion pressure (CPP), regulation of cerebral blood flow and volume, CSF absorption capacity, brain compensatory reserve, and content of vasogenic events. Some of these parameters allow prediction of prognosis of survival following head injury and optimisation of "CPP-guided therapy". In hydrocephalus CSF dynamic tests aid diagnosis and subsequent monitoring of shunt function.

Blood Pressure↗
PubMed2002

Phenylephrine increases cerebral perfusion pressure without increasing intracranial pressure in rabbits with balloon-elevated intracranial pressure.

Using a rabbit model of intracranial hypertension, we studied the effects of infusion of phenylephrine on intracranial pressure (ICP) and cerebral perfusion pressure (CPP). Seven New Zealand white rabbits were anesthetized with isoflurane and normocapnia was maintained. An extradural balloon was used to raise ICP to 25 +/- 1 mm Hg. Infusion of phenylephrine increased mean arterial blood pressure (MAP) (77 +/- 6 --> 95 +/- 8 mm Hg) and CPP (52 +/- 7 --> 70 +/- 7 mm Hg). ICP was unchanged during infusion of phenylephrine (25 +/- 1 vs. 25 +/- 2 mm Hg). The phenylephrine infusion was stopped after 45 minutes and MAP returned to baseline (76 +/- 8 mm Hg). We conclude that phenylephrine increased CPP because of its effect on MAP, but did not alter ICP. Phenylephrine may be used to increase CPP without raising ICP when autoregulation is intact.

Animals↗
PubMed1997

Influence of body position on tissue-pO2, cerebral perfusion pressure and intracranial pressure in patients with acute brain injury.

It is a common practice to position head-injured patients in bed with the head elevated above the level of the heart in order to reduce intracranial pressure (ICP). This practice has been in vivid discussion since some authors argue a horizontal body position will increase the cerebral perfusion pressure (CPP) and therefore improve cerebral blood flow (CBF). However, ICP is generally significantly higher in the horizontal position. The aim of this study was to evaluate changes in regional microcirculation using tissue pO2 (ti-pO2), as well as changes in cerebral perfusion pressure (CPP) and intracranial pressure induced by changes in body position in patients with head injury. The effect of 0 degree and 30 degrees head elevation on ti-pO2. CPP, ICP and arterial blood pressure (MABP) was studied in 22 head injured patients during day 0-12 after trauma. The mean ICP was significantly lower at 30 degrees head elevation than at 0 degree (14.1 + 8.6 vs. 19.9 + 8.3 mmHg). While MABP was unaffected by head elevation, CPP was slightly higher at 30 degrees than at 0 degree (76.5 + 13.5 vs. 71.5 + 13.2 mmHg). However, regional ti-pO2 was unaffected by body position (30 degrees vs. 0 degree: 24.9 + 13.1 vs. 24.7 + 12.9 mmHg). In addition, there was no change in the time course after trauma concerning these findings in the individual patients. The data indicate that a moderate head elevation of 30 degrees reduces ICP without jeopardizing regional cerebral microcirculation as monitored using a polarographic ti-pO2 microcatheter.

Acute Disease↗
PubMed1992

High-frequency oscillatory ventilation compared with conventional mechanical ventilation in newborn lambs: effects of increasing airway pressure on intracranial pressures.

We tested the hypothesis that intracranial pressures and cerebral perfusion pressure in the newborn are more seriously affected by increasing airway pressure during high-frequency oscillatory ventilation (HFOV) than during conventional mechanical ventilation (CMV). Mean airway pressure was acutely elevated in stepwise fashion to 25 cm H2O in six anesthetized, paralyzed newborn lambs. Pressure (mean +/- SE) increased similarly during HFOV and CMV in the jugular vein (7 +/- 1 and 8 +/- 1 cm H2O, respectively), the sagittal sinus (6 +/- 1 and 7 +/- 1 cm H2O), and the cerebrospinal fluid of the lateral ventricle (4 +/- 1 and 6 +/- 1 cm H2O). Decreases in arterial blood pressure (-13 +/- 2 and -10 +/- 2 cm H2O) and cerebral perfusion pressure (-17 +/- 2 and -16 +/- 2 cm H2O) were also similar during HFOV and CMV. Intracranial pressure-volume curves were generated by incrementing cerebrospinal fluid volume in eight lambs. Curves generated during HFOV and CMV were similar, reflecting a similar intracranial compliance during the two ventilatory modes. These data indicate that intracranial compliance and the effects of increasing airway pressure upon intracranial pressures are not significantly different between HFOV and CMV.

Air Pressure↗
PubMed1991

Management of head injury. Treatment of abnormal intracranial pressure.

Intracranial hypertension is recognized as a fundamental pathophysiologic process in brain injury. Although the exact pressure level defining intracranial hypertension remains to be firmly established, the majority of evidence available currently suggests that ICP should generally be treated when it exceeds 20 mm Hg. We suggest that lesions in the temporal lobe be treated at 15 mm Hg owing to the special relationship of this region to the brain stem. Along with the individual intracranial pressure reading, however, the course of the pressure over time and the status of the intracranial compliance as reflected in the ICP waveform must be considered when evaluating the intracranial dynamics. There is mounting evidence that patients with intracranial hypertension may comprise a heterogeneous group and that subgroups differ in their optimal treatment strategies. Although we cannot as yet identify such groups, factors such as age, CT diagnosis, responsiveness to hyperventilation, pressure-volume index, and ICP waveform are emerging as important differentiating factors. In particular, young patients with absent perimesencephalic cisterns and a tight brain on CT scan who manifest intracranial hypertension may comprise a group more suitable for treatment with hyperventilation and hypnotics than with osmotic agents. Although this is yet to be firmly established, currently it should be considered when such a patient responds poorly early in the course of conventional therapy for raised ICP. Treatment of intracranial hypertension remains rooted in the conventional therapeutic maneuvers. Maintenance of the basic homeostatic state of the patient is to be supplemented with head elevation, sedation, pharmacologic paralysis, hyperventilation, CSF drainage, and osmotic therapy as indicated. Outside of the special considerations discussed earlier, barbiturates should only be considered in patients with refractory intracranial hypertension without preexisting cardiovascular contraindications. Although several other agents have shown promise, currently the most exciting agent appears to be etomidate, which may prove quite useful. As ICP is better defined and understood, many significant and experimentally approachable questions are recognized. The basic mechanisms of raised ICP are slowly becoming elucidated. Clinical clues with which to subdivide patients with intracranial hypertension are being defined. New agents with efficacy in lowering raised ICP are appearing, and determination of their mechanisms of action may provide insight into the underlying disorder.

Brain Edema↗
PubMed2000

Experimental evaluation of the Spiegelberg intracranial pressure and intracranial compliance monitor. Technical note.

The goal of this study was to compare the Spiegelberg intraventricular intracranial pressure (ICP)/intracranial compliance monitoring device, which features an air-pouch balloon catheter, with existing gold-standard methods of measuring ICP and intracranial compliance. A Spiegelberg intraventricular catheter, a standard intraventricular catheter, and a Codman intraparenchymal ICP microsensor were placed in five sheep, which previously had been given anesthetic and paralytic agents, to allow comparative measurement of ICP at incremental levels (range 5-50 mm Hg). Intracranial pressure measured using the Spiegelberg intraventricular air-pouch balloon catheter displayed a linear correlation with ICP measured using the standard intraventricular fluid-filled catheter (r2 = 0.9846, p < 0.001; average bias -0.74 mm Hg), as well as with ICP measured using the Codman intraparenchymal strain-gauge sensor (r2 = 0.9778, p < 0.001; average bias 0.01 mm Hg). Automated measurements of intraventricular compliance obtained using the Spiegelberg compliance device were compared with compliance measurements that were made using the gold-standard manual cerebrospinal fluid bolus injection technique at ICPs ranging from 5 to 50 mm Hg, and a linear correlation was demonstrated between the two methods (r2 = 0.7752, p < 0.001; average bias -0.019 ml/mm Hg). The Spiegelberg air-pouch ICP/compliance monitor provides ICP and compliance data that are very similar to those obtained using both gold-standard methods and an intraparenchymal ICP monitor over a range of pathophysiological ICPs. The automated closed Spiegelberg system offers practical advantages for the measurement of intraventricular compliance. Assessment of the clinical utility and robustness of the Spiegelberg system, together with the development of an intraparenchymal device, would enhance the clinical utility of automated compliance measurement and expand the range of its applications.

Animals↗
PubMed1996

[Prevention of increase of blood pressure and intracranial pressure during endotracheal intubation in neurosurgery: esmolol versus lidocaine].

OBJECTIVES: To compare the preventive effects of esmolol and lidocaine on the increase in mean arterial pressure (MAP) and intracranial pressure (ICP) during endotracheal intubation in neurosurgery. STUDY DESIGN: Comparative, randomised, double-blind study. PATIENTS: Twenty-two patients, physical status ASA I or II, undergoing neurosurgery, and randomised into two groups (esmolol group and lidocaine group). METHODS: After induction of anaesthesia with thiopentone, vecuronium, fentanyl and isoflurane, one group received iv esmolol 1.5 mg.kg-1 and the other iv lidocaine 1.5 mg.kg-1, 130 sec before endotracheal intubation. The MAP measured with a radial catheter, the ICP obtained with a lumbar subarachnoid catheter and the cerebral perfusion pressure (CPP, calculated from MAP and ICP) were assessed before induction of anaesthesia, before esmolol or lidocaine injection, and before intubation, during the maximal change in MAP, as well as 2 and 5 minutes after intubation. RESULTS: The time course of MAP, ICP and CCP were similar throughout the study in the two groups, with a significant decrease (P < 0.05) of the CPP from 92 +/- 12 to 62 +/- 8 mmHg after esmolol, and from 96 +/- 12 to 68 +/- 15 mmHg after lidocaine. Following intubation, CPP increased significantly (P < 0.05) to 99 +/- 23 mmHg after esmolol and to 99 +/- 17 mmHg after lidocaine. The ICP increased also significantly (P < 0.05) after intubation from 11 +/- 6 to 17 +/- 10 mmHg in the esmolol group, and from 10 +/- 6 to 16 +/- 9 mmHg in the lidocaine group. CONCLUSIONS: Esmolol or lidocaine as an iv bolus of 1.5 mg.kg-1 before laryngoscopy and intubation do not completely prevent the increase in MAP and ICP.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

[The effect of anti-orthostatic action on the resorption of cerebrospinal fluid and various hemodynamic indicators in increased intracranial pressure].

Intracranial, systemic, arterial, and venous pressure as well as pressure in the sagittal sinus increased when dogs were given an antiorthostatic position. Changes of hemodynamic parameters in response to additional increase of intracranial pressure were more marked in an antiorthostatic than in a horizontal position. Hemodynamic shifts in an antiorthostatic position were attended by diminished rate of cerebrospinal fluid resorption and its increased production.

Animals↗
PubMed2001

Influence of positive end-expiratory pressure on intracranial pressure and cerebral perfusion pressure in patients with acute stroke.

BACKGROUND AND PURPOSE: We undertook this study to evaluate the influence of positive end-expiratory pressure (PEEP) on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in patients with acute stroke. METHODS: A total of 20 ventilated patients of a neurological intensive care unit were examined under a protocol entailing variation of PEEP to 4, 8, 12, and 4 mm Hg; mean arterial blood pressure (MAP), ICP, heart rate, and mean velocity of the middle cerebral arteries (V(m) MCA) were recorded. RESULTS: CPP significantly changed depending on the various PEEP levels. No significant differences in remaining parameters were evident. Three distinct reaction patterns of the parameters monitored were observed: (1) All parameters remained stable through the various PEEP levels (15 patients, 40 examinations). (2) Increase in PEEP resulted in a significant decrease of MAP, while V(m) MCA remained unchanged, indicating an intact cerebral autoregulation. A slight (statistically insignificant) increase in ICP, which was significantly related to the MAP changes, was evident (7 patients, 16 examinations). (3) Increase in PEEP resulted in a decrease of MAP and V(m) MCA; ICP remained unchanged or demonstrated a slight decline (3 patients, 6 examinations). CONCLUSIONS: PEEP increase up to 12 mm Hg does not significantly influence ICP. The observed marked changes in CPP are mediated through the MAP. Thus, PEEP application should be safe, provided that MAP is maintained.

Adult↗
PubMed1999

Circadian rhythm of cerebral perfusion pressure and intracranial pressure in head injury.

The aim of the study was to determine if Cerebral Perfusion Pressure (CPP) and Intracranial Pressure (ICP), in patients with head injury, has a circadian rhythm. CPP and ICP data of 13 patients were analysed using the Regressive and Iterative Cosinor methods. The Regressive Cosinor method did not detect a strong 24-hour rhythm. Therefore, the Iterative Cosinor method was used to seek rhythms with period not necessarily equal to 24 hours. Studying consecutive patient days by the Iterative cosinor method showed that rhythm is present but the rhythm period was often not 24 hours. A significant rhythm in the range of 20-30 hours was detected in eight patients for CPP (62%) and in six patients for ICP (46%). To validate the results real and surrogate time series were compared. The clinical implications of rhythmic data analysis are discussed.

Adult↗
PubMed1998

Cerebral perfusion pressure and intracranial pressure in relation to neuropsychological outcome.

OBJECTIVE: The study attempted to examine the relationship between neuropsychological functioning and reduced cerebral perfusion pressure (CPP), raised intracranial pressure (ICP), and reduced mean arterial pressure (MAP), monitored during intensive care treatment. DESIGN: This prospective follow-up study included consecutive patients and evaluated outcome at 6 months postinjury by the administration of a neuropsychological test battery. SETTING: The study was conducted at the University Hospital of Gent, Belgium. PATIENTS AND PARTICIPANTS: Over a 30-month period, 43 patients were included. Inclusion criteria were the following: hospital admission following closed head injury. ICP monitoring, no medical history of central nervous system disease or mental retardation, survival for at least 6 months, and informed consent for participation. INTERVENTIONS: All patients received the hospital's standard treatment for head injury, which remained unchanged during the study period. MEASUREMENTS AND RESULTS: Reduced CPP was analyzed using the number of observed values below 70 mmhg, raised ICP using the number of values above 20 mmHg, and MAP using the number of values below 80 mmHg. The neuropsychological test battery included 11 measures of attention, information processing, motor reaction time, memory, learning, visuoconstruction, verbal fluency, and mental flexibility. No linear relationships were found between overall neuropsychological impairment and episodes of reduced CPP, raised ICP, or reduced MAP. CONCLUSIONS: Although reduced CPP and raised ICP are frequent, often fatal, complications of head injury, in survivors they do not seem to be related to later neuropsychological functioning.

Adult↗
PubMed1988

[The behavior of intracranial pressure and intracranial compliance in nifedipine-induced hypotension].

The influence of nifedipine induced hypotension on intracranial pressure (ICP) and intracranial compliance (ICC) was investigated in dogs without (group I, n = 8) and with (group II, n = 8) intracranial hypertension. ICP in group II was raised by gradual inflation of an epidurally placed balloon catheter. A volume-pressure-response curve (VPR) was established before and during the administration of nifedipine. In group II dogs angiotensin was infused before and during infusion of nifedipine in a dose sufficient to raise mean arterial pressure (MAP) by 30-40 mm Hg. An infusion of nifedipine (2 micrograms X kg-1 X min-1) subsequent to a bolus injection of nifedipine (10 micrograms X kg-1) resulted in a significant and sustained decrease in MAP (p less than 0.05) by 25% and 35% resp. due to a significant reduction in total peripheral resistance (p less than 0.05). ICP increased from 8.7 +/- 3.0 mm Hg to a maximum of 12.5 +/- 5.2 mm Hg in group I animals (p less than 0.05) and from 19.8 +/- 2.6 mm Hg to 24.8 +/- 7.2 mm Hg not significantly in group II dogs. The pressure-volume-index revealed a slight reduction of ICC in group I and a slight increase of ICC in group II resp. during nifedipine as compared to before nifedipine. When angiotensin was being administered in group II dogs before nifedipine was given, MAP increased by 40 +/- 5.8 mm Hg while ICP did not change significantly (+2 +/- 2.4 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗