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J. Vassilouthis

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Maria A. Poca, Juan Sahuquillo, Anna Vilalta and Angel Garnacho

Object

Ischemic lesions are highly prevalent in patients with traumatic brain injuries (TBIs) and are the single most important cause of secondary brain damage. The prevention and early treatment of these lesions is the primary aim in the modern treatment of these patients. One of the most widely used monitoring techniques at the bedside is quantification of brain extracellular level of lactate by using arteriojugular venous differences of lactate (AVDL). The purpose of this study was to determine the sensitivity, specificity, and predictive value of AVDL as an indicator of increases in brain lactate production in patients with TBIs.

Methods

Arteriojugular venous differences of lactate were calculated every 6 hours using samples obtained though a catheter placed in the jugular bulb in 45 patients with diffuse head injuries (57.8%) or evacuated brain lesions (42.2%). Cerebral lactate concentration obtained with a 20-kD microdialysis catheter implanted in undamaged tissue was used as the de facto gold standard.

Six hundred seventy-three AVDL determinations and cerebral microdialysis samples were obtained simultaneously; 543 microdialysis samples (81%) showed lactate values greater than 2 mmol/L, but only 21 AVDL determinations (3.1%) showed an increase in brain lactate. No correlation was found between AVDL and cerebral lactate concentration (ρ = 0.014, p = 0.719). Arteriojugular venous differences of lactate had a sensitivity and specificity of 3.3 and 97.7%, respectively, with a false-negative rate of 96.7% and a false-positive rate of 2.3%.

Conclusions

Arteriojugular venous differences of lactate do not reliably reflect increased cerebral lactate production and consequently are not reliable in ruling out brain ischemia in patients with TBIs. The clinical use of this monitoring method in neurocritical care should be reconsidered.

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Maria A. Poca, Maria Mataró, Maria Del Mar Matarín, Fuat Arikan, Carmen Junqué and Juan Sahuquillo

Object. Data from many studies have demonstrated that shunt insertion in patients with idiopathic normal-pressure hydrocephalus (NPH) is associated with high morbidity and a lack of significant improvement; however, the use of strict diagnostic and treatment protocols can improve the results of surgery in these patients. The primary aim in this prospective study was to analyze the results of shunt placement in 43 patients with idiopathic NPH. A secondary aim was to determine the relationship between several clinical and neuroimaging factors, and patient outcome after surgery.

Methods. Thirty men and 13 women with a mean age of 71.1 ± 6.9 years participated in this study. All patients underwent clinical, neuropsychological, and radiological assessment before and 6 months after surgery. In all patients continuous monitoring of intracranial pressure was performed using a fiberoptic extradural sensor. In 31 patients cerebrospinal fluid dynamics were also determined. Eighty-six percent of patients showed clinical improvement after shunt insertion, 11.6% showed no change, and 2.3% exhibited some worsening. Gait improved in 81.4% of the patients, sphincter control in 69.8%, and cognitive dysfunction in 39.5%. There was no treatment-related death. Early or late postsurgical complications occurred in six patients (14%), although all of these complications were minor or were satisfactorily resolved. The complete clinical triad, cortical sulci size, and periventricular lucencies were related to outcome, whereas patient age, symptom duration, ventricular dilation, and the degree of presurgical dementia were unrelated to outcome.

Conclusions. Given the correct diagnosis, shunt insertion can produce marked improvement in patients with idiopathic NPH syndrome, causing few deaths and few clinically relevant complications.

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Maria A. Poca, Juan Sahuquillo, Maria A. Barba, Jose D. Añez and Fuat Arikan

Object

Continuous intracranial pressure (ICP) monitoring is performed in selected patients with hydrocephalus to determine whether shunt placement is required. The mean ICP is usually calculated from end-hour readings manually recorded by nurses. The aim of this study was to evaluate the accuracy of manual recordings by comparing nurses' end-hour ICP readings with those of an online computerized ICP monitoring system that records one ICP value per second.

Methods

Continuous ICP monitoring was performed using a fiberoptic extradural sensor in 115 patients with hydrocephalus of different origins. A notebook computer was connected to an ICP monitor and was programmed to register one ICP value per second. In all patients, mean ICP values were calculated from data recorded manually by nurses at the end of every hour and from data recorded by the computer within the preselected time period. The two methods were compared using correlation analysis and the Bland and Altman method.

The median number of ICP values noted manually by the nurses in each patient was 17 (interquartile range 15–18 readings), and that recorded by the software was 61,200 (interquartile range 54,000–64,800 readings). The correlation coefficient of the mean ICP values recorded by both methods was r = 0.99 (p < 0.001). The Bland and Altman analysis revealed a mean difference of 0.3 ± 1.26 mm Hg between the two methods and that they were equally valid with all mean ICP values.

Conclusions

The recording of end-hour ICP values by nurses is an accurate method of calculating the mean ICP after prolonged ICP monitoring in patients with hydrocephalus.

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Maria A. Poca, Francisco Martínez-Ricarte, Juan Sahuquillo, Roberto Lastra, Ramón Torné and Maria S. Armengol

Object

Continuous intracranial pressure (ICP) monitoring using an epidural sensor is a common technique used in selected neurosurgical patients. The aim of this study was to assess the safety and accuracy of the Neurodur-P epidural sensor in the clinical setting.

Methods

The zero drift, as well as the medical and technical complications, of using the Neurodur-P sensor placed in the epidural space was evaluated in 106 patients with hydrocephalus of varying causes or with suspected intracranial hypertension.

Results

The median duration of ICP monitoring was 8 days (interquartile range [IQR] 6–12 days). In 78 (73.6%) of the 106 patients the pressure reading was recorded at sensor removal. No zero drift was observed in 28 sensors. The median drift was 0 mm Hg with an IQR of −1 to 1 mm Hg. No significant differences were found between patients monitored for ≤ 5 days and those monitored for > 5 days (t = 535, p = 0.100). No correlation was found between zero drift and monitoring time (r = 0.153, p = 0.181). Of the 83 patients with a follow-up computed tomography scan, 3 showed a < 1 ml collection of blood at the catheter tip. No clinical infections could be attributed to the devices. Only 1 sensor malfunctioned.

Conclusions

Continuous ICP monitoring using the Neurodur-P sensor is safe, reliable, and easy to perform. At present, using this device is the authors' standard method for the long-term monitoring of patients with alterations in complex cerebrospinal fluid dynamics or with implanted shunts.

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Maria A. Poca, Maria Mataró, Mar Matarín, Fuat Arikan, Carme Junqué and Juan Sahuquillo

Object

The authors set out to describe the outcome in a subgroup of patients with normal-pressure hydrocephalus (NPH) in whom prognostic factors were poor. This subgroup of patients who had received shunts was selected according to strict criteria.

Methods

From a cohort of 56 patients with NPH in whom shunts were placed, the authors selected a subgroup with four of the factors traditionally considered to indicate poor prognosis: idiopathic type, cortical atrophy, longstanding symptoms, and presence of dementia in addition to old age. Twelve patients met the inclusion criteria.

After receiving shunts, 92% of the patients showed clinical improvement on the NPH scale; gait improved in 100% of patients, sphincter control in 90%, and dementia in 33%. Improvement was significant for gait and sphincter control, general NPH score, and most daily life activity scales. No significant differences regarding clinical, cognitive, or functional changes following surgery were found in comparison with the rest of patients (the good prognosis subgroup).

Conclusions

The clinical condition of patients with NPH who present with traditionally accepted markers of poor prognosis can improve after surgery, especially as regards gait and sphincter control. The authors assert that the presence of these markers should not be considered to be an absolute criterion for ruling out shunt surgery in cases of NPH syndrome.

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F. Contratti, M. F. Fraioli and G. Cacciotti

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Dulce Moncho, Maria A. Poca, Teresa Minoves, Alejandro Ferré, Victoria Cañas and Juan Sahuquillo

OBJECTIVE

In this study, the authors describe the brainstem auditory evoked potential (BAEP) and somatosensory evoked potential (SSEP) alterations found in a large cohort of patients with Chiari malformation Type 1 (CM-1), the relationship between the BAEPs/SSEPs and the clinical findings, the abnormalities in patients with associated syringomyelia, and the clinical and neuroradiological risk factors that are associated with abnormal evoked potentials (EPs).

METHODS

A prospectively collected database containing 545 patients with CM-1 was queried to search for patients satisfying the following criteria: 1) an age of at least 14 years, 2) neuroradiological criteria of CM-1, 3) no prior Chiari-related surgeries, and 4) preoperative EP studies conducted at the authors' institution. The 200 patients included in this cohort were classified into CM-0, CM-1, and CM-1.5 subtypes. Linear, planimetric, and angular measurements of the posterior fossa were conducted, as well as syringomyelia measurements. Two separate multiple logistic regression models were used, one to predict the covariates associated with abnormal BAEPs, and a second model to explore the variables associated with an abnormal SSEP. In these models, the BAEPs and SSEPs were dichotomized as being normal or abnormal.

RESULTS

Headaches were the main symptom in 70.5% of the patients, and Valsalva-induced headaches were most frequent in patients with CM-1 and CM-1.5 compared with patients with CM-0 (p = 0.031). BAEPs were abnormal in 38.5% of patients, and abnormal SSEPs were found in 43.5% of the entire cohort. Syringomyelia was most frequent in patients with CM-0 (64.3%) and CM-1 (51.1%) compared with those with CM-1.5 (34.7%; p = 0.03). Age (OR 1.03, 95% CI 1.00–1.06), the degree of tonsillar herniation (OR 1.08, 95% CI 1.01–1.16), and lower cranial nerve dysfunction (OR 3.99, 95% CI 1.29–14.01) had a statistically significant correlation with abnormal BAEPs. Only age (OR 1.07, 95% CI 1.04–1.10) and the degree of tonsillar herniation (OR 1.11, 95% CI 1.04–1.19) had a statistically significant correlation with abnormal SSEPs.

CONCLUSIONS

A high percentage of patients with CM-1 exhibited EP alterations regardless of their clinical or radiological findings. These findings suggest that EPs do not add any clinically relevant information nor are they helpful in establishing which symptomatic patients with CM should undergo surgical treatment. However, BAEP and SSEP studies clearly play an important role in incidentally detected patients with CM and may help to establish objective evidence of subclinical dysfunctions. In addition, neurophysiological studies may help to define subgroups of patients who require further testing and follow-up to personalize strategies for the management of incidental and oligosymptomatic patients.

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Aintzane Urbizu, Alex Ferré, Maria-Antonia Poca, Alex Rovira, Juan Sahuquillo, Bryn A. Martin and Alfons Macaya

OBJECTIVE

Traditionally, Chiari malformation Type I has been related to downward herniation of the cerebellar tonsils as a consequence of an underdeveloped posterior cranial fossa. Although the common symptoms of Chiari malformation Type I are occipital headaches, cervical pain, dizziness, paresthesia, and sensory loss, patients often report symptoms related to pharyngeal dysfunction such as choking, regurgitation, dysphagia, aspiration, chronic cough, and sleep disorders. In addition, tracheal intubation is often difficult in these patients. The purpose of this study was to analyze the morphological features of the oropharynx and oral cavity in patients with Chiari malformation Type I to help identify underlying anatomical anomalies leading to these debilitating symptoms.

METHODS

Seventy-six adult patients with symptomatic Chiari malformation Type I with cerebellar tonsillar descent greater than 5 mm below the foramen magnum and a small posterior cranial fossa and 49 sex-matched controls were selected to perform a retrospective case-control MRI-based morphometric study in a tertiary hospital. Eleven linear and areal parameters of the oropharyngeal cavity on midsagittal T1-weighted MRI were measured and the average values between patients and control cohorts were compared. Correlations between variables showing or approaching statistical significance in these structures and posterior cranial fossa measurements related with the occipital bone were sought.

RESULTS

Significant differences were detected for several oropharynx and oral cavity measures in the patient cohort, primarily involving the length and thickness of the soft palate (p = 9.5E-05 and p = 3.0E-03, respectively). A statistically significant (p < 0.01) moderate correlation between some of these variables and posterior cranial fossa parameters was observed.

CONCLUSIONS

The existence of structural oropharyngeal and oral cavity anomalies in patients with Chiari malformation Type I was confirmed, which may contribute to the frequent occurrence of respiratory and deglutitory complications and sleep disorders in this syndrome.