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Biomedical subjects

C Tommasino

Publications and source records attributed to C Tommasino.

At least 19 recordsLinked to original sources
PubMed1997

7.5% hypertonic saline versus 20% mannitol during elective neurosurgical supratentorial procedures.

This prospective randomized clinical study was designed to compare the effects of equal volumes of 7.5% hypertonic saline solution (HS) or 20% mannitol (M) on brain bulk and lumbar cerebrospinal fluid pressure (CSFP) during elective neurosurgical procedures (aneurysm, arteriovenous malformation, or tumor). After informed consent, 50 American Society of Anesthesiologists physical Status I (ASA I) patients were randomly assigned to M (n = 25) or HS (n = 25) groups. Anesthesia protocol was identical for both, and variables monitored included mean arterial blood pressure (MAP), heart rate (HR), central venous pressure (CVP), CSF pressure (CSFP), arterial blood gases (PaCO2 30-35 mm Hg), serum sodium, potassium, and osmolality, and diuresis. The study period started before hypertonic solution administration (T0) and ended at the opening of the dura mater or 60 min after T0. Data were assessed with repeated measures analysis of variance and Student t test with Bonferroni correction (p < or = 0.05). MAP and CVP were the same in the two groups. After treatment, osmolality increased, and the increase at T15 was higher in HS-treated patients [316.6 +/- 9.3 vs. 304.0 +/- 12.0 (SD) mOsmol/kg; p < 0.001]. Sodium decreased after M and increased after HS. During the study, brain bulk was always considered satisfactory. CSFP was not different between M and HS groups and significantly decreased overtime (p = 0.0056) with no difference between treatments. The results of the present study demonstrate that hypertonic saline is as effective as mannitol in reducing the brain bulk and the CSFP during elective neurosurgical procedures under general anesthesia.

Blood Pressure↗
PubMed1997

[Interaction of soda lime and halogenated anesthetics].

The increased use of soda lime for low flow anaesthesia leads to some problems related to the interaction with halogenated agents. These agents may be absorbed by soda lime or degradated according to their water content. Halothane and enflurane, in contact with soda lime, produce some metabolites, but their concentration is low when compared to their own lethal concentration. Sevoflurane degradates to four compounds. Compound A may reach a value between 13.3-42.1 ppm in the inspired fraction: these values are 50-100 times lower than the toxic concentrations. Isoflurane and desflurane are degradable at very low extent. Some case reports of unexpected high carboxyhemoglobin levels during anaesthesia indicate the possibility of CO production from soda lime and baralyme when halogenated agents are used. This reaction occurs only with anaesthetics containing CHF2-moiety (isoflurane, enflurane and desflurane) and when some specific factors make soda lime or baralyme completely dry. Low flow anaesthesia preserves the moisture content of the soda lime and protects from carbon monoxide production, by increasing water content in the circle.

Absorption↗
PubMed1996

Peri-operative prophylaxis with phenytoin: dosage and therapeutic plasma levels.

Early postoperative epilepsy is a frequent complication of supratentorial intracranial surgery. The lack of consensus on prophylaxis of early postoperative seizures with phenytoin (PHT) may be due to the different dosages used in several studies, owing to inadequate therapeutic plasma level. The aim of this study was to evaluate which dosage of PHT can maintain the therapeutic range in the early postoperative period. Twenty patients operated on for supratentorial neoplasms were randomly allocated to receive, during the last hour of the surgical procedure, loading doses of either 10 mg/kg (group A, n = 10) or 15 mg/kg (group B, n = 10) of PHT. PHT infusion rate never exceeded 30 mg/min. Six hours after the loading dose, PHT maintenance treatment (250 mg, i.v., every 8 hours) was started in all patients. PHT plasma levels were evaluated from the end of the intra-operative loading infusion up to 24 h. During the first six hours after the loading dose, phenytoin plasma levels fell below the therapeutic range (10-20 mg/l) in 7 out of the 10 patients receiving 10 mg/kg, while in the patients treated with 15 mg/kg, PHT plasma levels were always in the therapeutic range (P < or = 0.0001). PHT maintenance dose was sufficient to keep plasma levels within the therapeutic range in 8 patients in group A, and in all the patients in group B. It is concluded that a loading dose of 15 mg/kg, followed by postoperative treatment, is necessary to guarantee therapeutic plasma levels of phenytoin in the immediate postoperative period, when seizure risk is very high.

Adult↗
PubMed1996

Cerebral ischemia after venous air embolism in the absence of intracardiac defects.

Cerebral air embolism occurred in a patient undergoing posterior fossa surgery performed in the sitting position for acoustic neuroma removal. The patient experienced two episodes of venous air embolism, as evidenced by precordial Doppler, end-tidal carbon dioxide reduction, and oxygen desaturation. In both cases, air was aspirated from the central venous catheter; during the second episode there was arterial hypotension and electrocardiogram changes, and air bubbles were visualized in the cerebellar arteries. The patient did not regain consciousness after surgery and developed early tonic-clonic convulsions and electroencephalogram status epilepticus, which was treated with barbiturate coma. Intracardiac septal defects were not detected by transesophageal echocardiography, and computerized tomography of the brain demonstrated multifocal discrete ischemic areas in the cerebral hemispheres. The patient died 6 days after surgery without having regained consciousness. This case appears to represent the occurrence of transpulmonary passage of venous air embolism.

Brain Ischemia↗
PubMed1996

Propofol anaesthesia in spontaneously breathing paediatric patients during magnetic resonance imaging.

BACKGROUND: The aim of this study was to evaluate the use of propofol to induce and maintain anaesthesia in spontaneously breathing paediatric patients (age 2 weeks-11 years) during Magnetic Resonance Imaging (MRI) of the CNS. METHODS: All patients were spontaneously breathing, without intubation, and received supplemental O2. Pulse rate, blood pressure (BP), electrocardiogram and EtCO2 were recorded in all patients, and in 38 subjects SpO2 was also monitored. Patients were divided in 2 groups according to their body weights: Group A (n = 34, bwt < or = 10 kg), and Group B (n = 48, bwt > 10 kg). RESULTS: Dosage of propofol during the time of induction (from insertion of the i.v. cannula to positioning on the MRI table) was significantly higher in smaller children (Group A; 5.4 +/- 2.2 (SD) mg/kg) as compared to children with bwt above 10 kg (Group B; 3.7 +/- 1.6 mg/kg). Propofol dosage for maintenance of anaesthesia was significantly higher in smaller children (Group A: 10.1 +/- 5.7 vs Group B: 7.1 +/- 3.0 mgkg-1 h-1, P = 0.003). During the time of induction, transient episodes of reduced BP (< or = 20%) occurred in 6 patients in Group A and 2 patients in Group B. During anaesthesia in Group B there was 1 episode of oxygen desaturation (95%), and 3 episodes of short and mild increases of EtCO2(< or = 52 mmHg). No other side effects occurred in any patient. MRI studies were successfully completed, only 3 sequences (Group A) had to be restarted. CONCLUSION: Propofol can be safely used for total intravenous anaesthesia in children undergoing MRI.

Anesthesia Recovery Period↗
PubMed1996

Coagulation activation and fibrinolytic imbalance in subjects with idiopathic antiphospholipid antibodies--a crucial role for acquired free protein S deficiency.

To explore the coagulation/fibrinolytic balance and its relation with free protein S (f-PS) in subjects with antiphospholipid antibodies (aPLs) outside the setting of autoimmune inflammatory disorders, we carried out a cross-sectional study on 18 thrombotic patients with primary antiphospholipid syndrome and 18 apparently healthy subjects with persistence of idiopathic aPLs. Prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin complex (TAT) and D-Dimer (D-D) were taken as markers of thrombin generation and fibrin turnover. Mean F1 + 2 levels were higher in thrombotic (p = 0.006) and non-thrombotic subjects (p = 0.0001) than in controls as were those of D-D (p < 0.0001 and p = 0.003 respectively). TAT levels did not differ. Lower mean levels of f-PS were found in thrombotic (p = 0.0006) and non-thrombotic subjects (p = 0.002) than in controls. Within both groups, mean F1 + 2 levels were higher in subjects who had low f-PS levels compared to those with normal f-PS levels (p = 0.01). Gender analysed data revealed blunted tPA release (venous occlusion test) in thrombotic females (from 16.80 +/- 0.79 to 21.3 +/- 3.9 ng/nl, NS) but not in thrombotic males (from 18.2 +/- 2.0 to 33.7 +/- 4.9 ng/ml, p=0.01) nor in asymptomatic subjects of either sex. Also, in both patient groups females had higher mean PAI than males (p < 0.0002) and than control females (p < 0.02). Low free protein S was found in 100% of non-thrombotic and in 90% of thrombotic patients with defective fibrinolysis. These data are consistent with increased thrombin generation, accelerated fibrin turnover and fibrinolysis abnormalities also in asymptomatic carriers of aPLs and highlight a central role for acquired f-PS deficiency in the thrombotic tendency of the antiphospholipid syndrome.

Adult↗
PubMed1995

Regional cerebral metabolism of glucose in comatose and vegetative state patients.

Regional cerebral metabolism of glucose (rCMRglu) was evaluated in patients who were in a coma and vegetative state to determine the level of brain function during these conditions. rCMRglu was measured in 17 discrete brain regions with (/-) [18F] -fluoro-2-deoxy-D-glucose (FDG) and positrn emission tomography (PET) in 15 patients with ;brain pathology subsequent to cardiorespiratory arrest (CA), head trauma (HT), or brain ischemia (BI) resulting from cerebrovascular accident or brain surgery. Five comatose patients (Coma group, n = 5), and 10 vegetative state patients (VS, patients awake but not aware) were studied. The VA patients were subdivided, according to the length of their VS condition, into a VS group (n = 6, < 3 months if CA or BI patients, or < 12 months if HT patients) and a persistent vegetative state group (PVS, n = 4, > 3 months if CA or BI patients of > 12 months if HT patients.) Ten normal age-matched subjects served as control. Global CMRglu was 6.72 +/- 0.93 (+/-SD) mg/100 g/min in control subjects. It was significantly (p < - 0.001) reduced to 3.70 +/- 61 in coma, to 3.45 +/- in VS, and to 2.33 +/- 0.34 mg/100 g/min in PVS patients. rCMRglu was significantly reduced (p < - 01001) from control values in all the 17 structures surveyed in every patient. In the Coma and VS groups, there was an overlapping of rCMRglu in the majority of the brain structures. (ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Oncotic pressure and hemodilution].

The appropriate fluid therapy in neurosurgical patients remains an area of disagreement between neurosurgeons and anaesthesiologists. Fluid restriction has long been practiced in patients with brain pathology, in order to reduce or prevent the formation of cerebral oedema. This grows from a fear that rapid administration of fluids, particularly noncolloidal fluids, can enhance cerebral oedema, although there is a lack of experimental evidence to substantiate this belief. On the other hand, fluid restriction can lead to relative hypovolaemia, causing haemodynamic instability during anaesthesia and influence defavourably cerebral perfusion. The appropriate fluid management of patients with brain pathology requires a careful review of the Starling's law and a clear understanding of osmolality, oncotic pressure (OP) and the nature of the blood-brain barrier (BBB). The Starling equation of ultrafiltration states that the net movement of fluid between the intra- and extravascular compartments is the result of the summated influences of the pressure gradients (hydrostatic pressure, OP, and osmotic pressure) between those compartments and the properties of the barriers (capillary endothelium) that separate them. In most peripheral tissues this barrier is freely permeable to small molecules and ions and net fluid movement depends on intravascular hydrostatic pressure and OP. Under normal circumstances, intraluminal hydrostatic pressure is higher than interstitial pressure, favouring water egress. By contrast, intraluminal OP is higher than interstitial OP, favouring water retention. These forces do not balance exactly, and fluid accumulation is prevented by the lymphatics. If this net movement exceeds the capacity of the lymphatic clearance mechanisms, fluid accumulates, which is the definition of oedema.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1994

[Treatment of hypovolemia in brain injured patients].

The appropriate administration of intravenous fluids in neurosurgical patients remains an area of disagreement between neurosurgeons and anaesthetists. Fluid restriction has long been advocated by the former and is widely believed to reduce or prevent the formation of cerebral oedema. However, such restriction can lead to hypovolaemia which in turn can result in haemodynamic instability. Thus, brain homeostasis should be aimed for through adequate fluid administration and normal or slightly elevated mean arterial pressure. The properties of the endothelium differ between the brain and the remainder of the body. In most non CNS tissues the size of the junctions between endothelial cells averages 65 A. Proteins do not cross these gaps while sodium does. In the brain, the junction size is only 7 A, which is too small to allow crossing by sodium. Investigations with changes in osmotic and oncotic pressure have demonstrated that: 1) reducing osmolality results in oedema formation in all tissues including normal brain; 2) a decrease in oncotic pressure is only associated with peripheral oedema but not in the brain; 3) in case of brain injury, a decrease in osmolality elicits oedema in the part of brain which remained normal; 4) similarly, a decrease in oncotic pressure does not cause an increase in brain oedema in the injured part of the brain. Thus, a major reduction in oncotic pressure is unimportant for the brain, whereas changes in total osmolality are the dominant driving force at this level. To conclude, in a hypovolaemic patient with severe head injury, the crystalloid of choice is NaCl 0.9% and the colloid of choice is hydroxyethylstarch, both with an osmolality > 300 mosm.kg-1. Ringer-lactate is hypoosmotic (255 mosm.kg-1) and may cause or increase cerebral oedema. Mean arterial pressure should be maintained above 80 mmHg.

Blood Pressure↗
PubMed1993

[Acute stage of spinal injury (physiopathology). "Ischemic damage to the spinal cord"].

Several pathophysiological events follow spinal cord trauma. Vascular abnormality and changes in spinal cord blood perfusion occur immediately after injury primarily within the gray matter. Progressive biochemical and histological alterations take place both in gray and white matter subsequently. The significant metabolic and ionic alterations, all of which are interdependent (reduction in energy substrate, enzymes and neurotransmitters release alterations, ionic fluxes changes) result either in loss of functional activity or structural integrity in the injured spinal cord and remains a matter of speculation.

Humans↗
PubMed1992

[Transcranial Doppler for the monitoring of gas embolism in neurosurgical operations in the sitting position].

The risk of venous air embolism is significant in neurosurgical procedures performed in the sitting position. Monitoring for venous air embolism, therefore, is crucial and can be approached from several aspects. The most sensitive generally applicable clinical method for the detection of intracardiac gas is based on an application of the Doppler principle. The Authors describe the technique used to adapt a transcranial Doppler (TC 2-64 B, EME, Germany), and a probe designed to record the Doppler signal from intracranial arteries (Transcran FP 2, EME, Germany), as precordial Doppler in order to monitor venous air embolism in neurosurgical procedures performed in the sitting position.

Brain↗
PubMed1992

[Complications during preoperative embolization in intracranial meningioma].

We report a rare case of meningioma of the parieto-occipital convexity accompanied by hemorrhage in the tumor and in the subdural space that occurred while pre-operative embolization was being applied. The patient, a 48 year old woman, presented sudden headache and, in a few minutes, comatose status and decerebrate rigidity. A quick diagnosis with CT-scan of acute intratumoral and subdural hemorrhage and a rapid intervention on the patient led to complete recovery. The possible reason for the hemorrhage is the sudden change in blood pressure of pathologic small vessels triggered by embolization.

Brain Neoplasms↗