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N Stocchetti

Publications and source records attributed to N Stocchetti.

At least 55 records · Page 3Linked to original sources
PubMed1998

Estimation of the main factors affecting ICP dynamics by mathematical analysis of PVI tests.

A simplified model of intracranial dynamics is used to reproduce the intracranial pressure (ICP) time pattern in 20 patients with severe brain damage during PVI tests. A comparison of model responses and clinical tracings was achieved by minimizing a least square criterion function and adjusting just 5 parameters. These are: the CSF outflow resistance, the intracranial elastance coefficient, the autoregulation gain and time constant, and the basal values of arteriolar compliance. Based on the value of the autoregulation gain, the patients were classified into two groups: those with damaged autoregulation (8 out of 12) and those with preserved autoregulation (12 out of 20). Finally, analysis of the correlation between parameter estimates provided suggestions on the combination of a parameter changes which may have the greater impact on ICP in the individual cases. Once these parameters have been identified, they may become possible targets for therapeutic interventions.

Blood Flow Velocity↗
PubMed1998

[Monitoring and protection of the central nervous system in subarachnoid hemorrhage during intensive care].

Subarachnoid hemorrhage has cerebral and systemic consequences as well. The main purpose of admitting a patient in the Intensive Care setting is to provide protection, mainly by stabilizing fundamental physiological parameters. There are both systemic parameters and cerebral parameters to be controlled continuously, and cerebral parameters may consider the brain as a whole (global cerebral parameters as intracranial pressure) or may provide information on specific areas. Cerebral protection may be achieved only when multiparametric monitoring is instituted, since only the combination of many physiologic parameters provides information capable of identifying, and hopefully of treating, deleterious derangements.

Central Nervous System↗
PubMed1997

EBIC-guidelines for management of severe head injury in adults. European Brain Injury Consortium.

Guidelines for the management of severe head injury in adults as evolved by the European Brain Injury Consortium are presented and discussed. The importance of preventing and treating secondary insults is emphasized and the principles on which treatment is based are reviewed. Guidelines presented are of a pragmatic nature, based on consensus and expert opinion, covering the treatment from accident site to intensive care unit. Specific aspects pertaining to the conduct of clinical trials in head injury are highlighted. The adopted approach is further discussed in relation to other approaches to the development of guidelines, such as evidence based analysis.

Adult↗
PubMed1997

Intracranial pressure dynamics in patients with acute brain damage.

The time pattern of intracranial pressure (ICP) during pressure-volume index (PVI) tests was analyzed in 20 patients with severe acute brain damage by means of a simple mathematical model. In most cases, a satisfactory fitting between model response and patient data was achieved by adjusting only four parameters: the cerebrospinal fluid (CSF) outflow resistance, the intracranial elastance coefficient, and the gain and time constant of cerebral autoregulation. The correlation between the parameter estimates was also analyzed to elucidate the main mechanisms responsible for ICP changes in each patient. Starting from information on the estimated parameter values and their correlation, the patients were classified into two main classes: those with weak autoregulation (8 of 20 patients) and those with strong autoregulation (12 of 20 patients). In the first group of patients, ICP mainly reflects CSF circulation and passive cerebral blood volume changes. In the second group, ICP exhibits paradoxical responses attributable to active changes in cerebral blood volume. Moreover, in two patients of the second group, the time constant of autoregulation is significantly increased (>40 s). The correlation between the parameter estimates was significantly different in the two groups of patients, suggesting the existence of different mechanisms responsible for ICP changes. Moreover, analysis of the correlation between the parameter estimates might give information on the directions of parameter changes that have a greater impact on ICP.

Acute Disease↗
PubMed1996

Hypoxemia and arterial hypotension at the accident scene in head injury.

OBJECTIVE: To quantify the occurrence of arterial hypotension and arterial oxygen desaturation in a series of patients with head trauma rescued by helicopter. DESIGN: Prospective, observational study. MATERIALS AND METHODS: Arterial HbO2 was measured before tracheal intubation at the accident scene in 49 consecutive patients with head injuries. Arterial pressure was measured using a sphygmomanometer. MAIN RESULTS: Mean arterial saturation was 81% (SD 24.24); mean arterial systolic pressure was 112 mm Hg (SD 37.25). Airway obstruction was detected in 22 cases. Twenty-seven patients showed an arterial saturation lower than 90% on the scene, and 12 had a systolic arterial pressure of less than 100 mm Hg. The outcome was significantly worse in cases of hypotension, desaturation, or both. CONCLUSIONS: Hypoxemia and shock are frequent findings on patients at the accident scene. Hypoxemia is more frequently detected and promptly corrected, white arterial hypotension is more difficult to control. Both insults may have a significant impact on outcome.

Adolescent↗
PubMed1995

Intracranial pressure dynamics in patients with acute brain damage: a critical analysis with the aid of a mathematical model.

The time pattern of intracranial pressure (ICP) in response to typical clinical tests (i.e., bolus injection and bolus withdrawal of 1 to 4 mL of saline in the craniospinal space) was studied in 18 patients with acute brain damage by means of a mathematical model. The model includes the main biomechanical factors assumed to affect intracranial pressure, particularly cerebrospinal fluid (CSF) dynamics, intracranial compliance, and cerebral hemodynamics. Best fitting between model simulation curves and clinical tracings was achieved using the Powell minimization algorithm and a least-square criterion function. The simulation results demonstrate that, in most patients, the ICP time pattern cannot be explained merely on the basis of CSF dynamics but also requires consideration of the contribution of cerebral hemodynamics and blood volume alterations. In particular, only in a few patients (about 40% of total) the ICP monotonically returns toward baseline following the clinical maneuver. In most of the examined cases (about 60%), ICP exhibits an anomalous response to the same maneuver, characterized by a delayed increase after bolus injection and a delayed decrease after withdrawal. The model is able to explain these responses, imputing them to active intracranial blood volume changes induced by mechanisms controlling cerebral blood flow. Finally, the role of the main intracranial biomechanical parameters in the genesis of the ICP time pattern is discussed and a comparison with previous theoretical studies performed.

Acute Disease↗
PubMed1994

[Subarachnoid hemorrhage: cerebral damage, fluid balance, intracranial pressure and pressure-volume relation].

Changes in osmolality and electrolyte concentrations are observed frequently in patients with subarachnoid haemorrhage (SAH). Intracranial pressure (ICP) plays a determinant role in the development of secondary brain damage following SAH and may be caused by haemorrhage itself, oedema formation and disturbance of cerebrospinal fluid (CSF) dynamics. The relationships among these factors are the aim of this investigation. In 17 comatose SAH patients, ICP was monitored through a ventricular catheter; serial of pressure-volume index (PVI) and CSF formation and reabsorption were performed. Arterio-jugular differences for oxygen and lactate were measured. The average ICP recorded for each 12 hour interval was 18.9 mmHg (SD = 5.9); mean cerebral perfusion pressure (CPP) was 75 mmHg (SD = 13); the lowest CPP value was 30 mmHg. Mean PVI was 22.7 mL (SD = 7.4), ranging from 5 to 36. Eleven patients however, showed a PVI less than 15 mL at some point during testing. Values of CSF dynamics indicated disturbances of CSF reabsorption in 11 cases. When the cause of ICP rise was identified in CSF disturbances, treatment was successful, even in case of reduced PVI. Mean C(a-v)O2, corrected for a PaCO2 of 40 mmHg, was 3.7 mL.dL-1 (SD = 1.1) ranging from the extremely low value of 0.2 to 6.8 mL.L-1. Three patients with extremely low C(a-v)O2 values showed a cerebral production of lactate and developed areas of ischaemia on the CT scan. Hyponatraemia, considered as a sodium plasma concentration of less than 135 mmol.L-1, was detected in seven patients. Hyponatraemia was treated by infusion of hypertonic sodium solutions. Mannitol (1 g.kg-1.d-1 in four doses) was infused if the sodium plasma concentration was not corrected by the former treatment or if ICP exceeded 20 mmHg. Treatment was aimed at preserving cerebral perfusion by providing adequate pre-load, low viscosity (Ht 30%) and sustained arterial pressure. Correction of hyponatraemia was therefore achieved more through hypertonic fluids infusion than by using diuretics.

Adolescent↗
PubMed1994

Cerebral venous oxygen saturation studied with bilateral samples in the internal jugular veins.

The current literature reports many measurements (arteriovenous oxygen content difference and cerebral metabolic rate of oxygen, etc.) with samples from the internal jugular veins (IJs), obtained from either side of the neck, based on the assumption that a reliable sample of mixed venous blood can be drawn. We compared oxygen saturation in both IJs in 32 patients with head injuries to establish the similarities or discrepancies in the two veins. Both IJs were cannulated with 20-G catheters; in five patients, a fiberoptic catheter was used to obtain a continuous recording of the hemoglobin saturation. Blood samples were taken simultaneously from the two IJs and immediately processed; the total number of samples processed was 342, with an average of 5.34 paired samples from each patient. The mean and the standard deviation of the differences between the saturation of the two IJs were, respectively, 5.32 and 5.15. Fifteen patients showed differences greater than 15% in hemoglobin saturation; three more patients showed differences greater than 10% at some point during the investigation. Ultimately, only eight patients had differences of less than 5%. No relationship was found among the computed tomographic scan data and the pattern of hemoglobin saturation detected. Therefore, we were not able to identify the side more appropriate for monitoring in patients with bilateral, predominantly monolateral, cortical, or deeply located lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Trauma care in Italy: evidence of in-hospital preventable deaths.

The quality of a trauma system can be assessed by the rate of preventable deaths. A random selected sample of 110 trauma patients was examined using both clinical and autopsy data. The assessors were asked the following question: If this patient had sustained the accident in front of the hospital in a normal working day, might death have been prevented? Death was found to be unavoidable in 61 cases, in 25 cases death was classified potentially preventable; 11 cases were classified as clearly preventable death. The main failures of treatment were identified as errors and delays during the first phases of in-hospital assessment and care. An improvement in the pre-hospital phase will be almost useless if the quality of the definitive in-hospital management is not addressed.

Adolescent↗
PubMed1992

[Increasing the pressure of cerebral perfusion to control intracranial pressure].

ICP control can be achieved removing the surgical masses and manipulating the intracranial compartments; in the intensive care setting that can be attempted using CSF withdrawal or changing the cerebrovascular resistances, the intracranial blood content and the cerebral water content. The reduction of the ICP and the maintenance of a good cerebral perfusion pressure are the main aims of the therapy; when any standard treatment fails to control ICP a further attempt to preserve cerebral perfusion should be done by increasing the mean arterial pressure. In 10 patients with severe brain damage (GCS on admission ranging from 3 to 7, mean 5) from subarachnoid hemorrhage (3 cases) or trauma an infusion of dopamine (25-150 mg/h) and noradrenaline (0.4-2.4 mg/h) was started in case of intractable ICP. The ICP was defined intractable when the pressure was more than 40 mmHg for more than 5 m' after maximum therapy, as evaluated using the Therapy Intensity Level score. The infusion obtained a raise of the MAP of approximately 25% and a variable response on ICP. In 9 cases ICP dropped, in one case, instead, the ICP increased together with the arterial pressure. The reduction of ICP was 20-30%, with a good improvement of the CPP. The patients with a good response survived, the only patient without control of the ICP died. The physiopathologic mechanisms of this treatment are discussed; the most suitable explanation is indicated in an autoregulatory process. The infusion of cathecolamines can be harmful, and the patients eligible for this treatment must be carefully chosen. Notwithstanding this approach deserves further studies for the cases of intractable ICP.

Adult↗
PubMed1991

[Arterio-jugular difference of oxygen and intracranial pressure in comatose, head injured patients. I. Technical aspects and complications].

The monitoring of the comatose head injured patients is based on the recording of several data; the intracranial pressure measurements (ICP), associated with the arterial pressure recording, gives a good estimate of the cerebral perfusion pressure (CPP) but further information about the cerebral perfusion are needed. Based on the assumption that the cerebral metabolic rate is kept constant strong relationships exist between the cerebral blood flow (CBF) and the arterovenous difference of oxygen (AVDO2). In order to obtain samples of cerebral venous blood a catheter must be inserted in the internal jugular vein (IJ) with the tip of the cannula reaching the superior jugular bulb. In 224 patients we measured the ICP trough ventricular or subdural catheters; invasive measurement of the arterial pressure was also carried on in all the patients. In 45 patients we measured the AVDO2 and we tested the safety and the reliability of the jugular vein cannulation. During the insertion of the jugular catheters a slight increase of ICP, without any clinical significance, was recorded; in two cases (on a total of 45) accidental carotid puncture occurred. In 9 cases we tested the concordance of the oxygen content between the two IJs; looking at the mean values no statistical difference is detected between the two sides but in some cases relevant differences are recorded. In two cases we inserted the catheters more cranially, reaching a sinus of the cranial basis; the blood collected from these points carries less oxygen that the blood collected in the neck. The rate of infection in this series of ICP monitoring is very low (1.78%) and we had no bleeding at the moment of the insertion of the catheters. Since no significant complications related to the IJ cannulation were recorded we conclude that these techniques are safe and can be easily performed in the clinical setting. Further studies are required in order to investigate the clinical meaning of the differences in the IJs content of oxygen.

Adolescent↗
PubMed1991

[Arterio-jugular difference of oxygen and intracranial pressure in comatose, head injured patients. II. Clinical correlations].

The ICP monitoring is currently used in the treatment of the head injured patients in order to avoid dangerous increases of the pressure and critical reduction of cerebral perfusion pressure (CPP). The cerebral blood flow is dependent on the CPP and is kept constant, under normal circumstances, by autoregulation. When autoregulation is impaired or overwhelmed oxygen delivery becomes uncoupled to the metabolic needs of cerebral tissue: in such a condition the rate of oxygen extraction changes and the artero-jugular difference for O2 (AVDO2) reflects this change. The AVDO2 can be used as an estimate of the CBF and can detect a situation of hyperemia (low AVDO2) or ischemia (high AVDO2). In 224 comatose head injured patients the ICP was measured using ventricular or subarachnoid catheters: the CPP was continuously assessed and the outcome was evaluated six months after the trauma. In 45 patients the AVDO2 was studied and the data were corrected for a PaCO2 of 40 mmHg and investigated. The severity of the ICP is decisive for the prognosis and, accordingly, the number of times the CPP is below 60 mmHg plays a major role in the outcome. The mortality rate was 21% for the patients without ICP greater than 20 mmHg and 54% for the patients with severe increases in ICP. The mean values of AVDO2 were low, ranging around 4.6 vol%; only 4 patients showed some temporary evidence of ischemia, as assessed by an AVDO2 greater than 8 vol%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Clinical evaluation of atracurium besylate in patients at risk: major burns].

Atracurium besylate 0.5 mg/kg-1, an intermediate-duration non-depolarizing neuromuscular relaxant, was administered slowly (over 75 sec) in anesthesia induction of 61 patients with major thermal injury undergoing surgical excision and immediate skin-grafting procedures. Patients' mean +/- SD age was 40 +/- 9, body weight 64 +/- 2, burn size ranging from 20% to 90% of body surface area (BSA), postburn day of surgery 5th and more. Induction of anesthesia was carried out with sodium thiopental 2-5 mg/kg-1 plus fentanyl 2.8 micrograms/kg-1 e.v. and after few minutes atracurium 0.5 mg/kg-1 e.v. Anesthesia was maintained with N2O/O2 (70%/30%), isoflurane and small amounts of fentanyl. The mean arterial pressure and heart rate were recorded at I, II, III, IV, V min post atracurium administration. The endotracheal intubation conditions were assessed by a "IOT score". Results are expressed as mean value +/- standard deviation. The significance of the difference in mean values was analysed by t-test. Little haemodynamic changes occurred; intubating conditions showed a relative hyposensitivity of burn patients to atracurium, more severely burned patients (greater than 50-60%) exhibiting greater resistance.

Adolescent↗