Echography is mandatory for the initial management of critically ill patients: No

n/

Determinants of the cuff-leak test: a physiological study

INTRODUCTION: The cuff-leak test has been proposed as a simple method to predict the occurrence of post-extubation stridor. The test is performed by cuff deflation and measuring the expired tidal volume a few breaths later (V(T)). The leak is calculated as the difference between V(T )with and without a deflated cuff. However, because the cuff remains deflated throughout the respiratory cycle a volume of gas may also leak during inspiration and therefore this method (conventional) measures the total leak consisting of an inspiratory and expiratory component. The aims of this physiological study were, first, to examine the effects of various variables on total leak and, second, to compare the total leak with that obtained when the inspiratory component was eliminated, leaving only the expiratory leak. METHODS: In 15 critically ill patients mechanically ventilated on volume control mode, the cuff-leak volume was measured randomly either by the conventional method (Leak(conv)) or by deflating the cuff at the end of inspiration and measuring the V(T )of the following expiration (Leak(pause)). To investigate the effects of respiratory system mechanics and inspiratory flow, cuff-leak volume was studied by using a lung model, varying the cross-sectional area around the endotracheal tube and model mechanics. RESULTS: In patients Leak(conv )was significantly higher than Leak(pause), averaging 188 ± 159 ml (mean ± SD) and 61 ± 75 ml, respectively. In the model study Leak(conv )increased significantly with decreasing inspiratory flow and model compliance. Leak(pause )and Leak(conv )increased slightly with increasing model resistance, the difference being significant only for Leak(pause). The difference between Leak(conv )and Leak(pause )increased significantly with decreasing inspiratory flow (V'(I)) and model compliance and increasing cross-sectional area around the tube. CONCLUSION: We conclude that the cross-sectional area around the endotracheal tube is not the only determinant of the cuff-leak test. System compliance and inspiratory flow significantly affect the test, mainly through an effect on the inspiratory component of the total leak. The expiratory component is slightly influenced by respiratory system resistance

Comparative studies of RNFL thickness measured by OCT with global index of visual fields in patients with ocular hypertension and early open angle glaucoma

Sergios Taliantzis, Dimitris Papaconstantinou, Chrysanthi Koutsandrea, Michalis Moschos, Michalis Apostolopoulos, Gerasimos GeorgopoulosAthens University Medical School, Department of Ophthalmology, Athens, GreecePurpose: To compare the functional changes in visual fields with optical coherence tomography (OCT) findings in patients with ocular hypertension, open angle glaucoma, and suspected glaucoma. In addition, our purpose is to evaluate the correlation of global indices with the structural glaucomatous defect, to assess their statistical importance in all the groups of our study, and to estimate their validity to the clinical practice.Methods: One hundred sixty nine eyes (140 patients) were enrolled. The patients were classified in three groups. Group 1 consisted of 54 eyes with ocular hypertension, group 2 of 42 eyes with preperimetric glaucoma, and group 3 of 73 eyes with chronic open angle glaucoma. All of them underwent ophthalmic examination according to a prefixed protocol, OCT exam (Stratus 3000) for retinal nerve fiber layer (RNFL) thickness measurement with fast RNFL thickness protocol and visual fields (VF) examination with Octopus perimeter (G2 program, central 30–2 threshold strategy). Pearson correlation was calculated between RNFL thickness and global index of VF.Results: A moderate correlation between RNFL thickness and indices mean sensitivity (MS), mean defect (MD) and loss variance (LV) of VF (0.547, -0.582, -0.527, respectively; P < 0.001) was observed for all patients. Correlations of the ocular hypertension and preperimetric groups are weak. Correlation of RNFL thickness with global indices becomes stronger as the structural alterations become deeper in OCT exam. Correlation of RNFL thickness with the global index of VF, in respective segments around optic disk was also calculated and was found significant in the nasal, inferior, superior, and temporal segments.Conclusion: RNFL average thickness is not a reliable index for early diagnosis of glaucoma and for the follow-up of patients with ocular hypertension. Segmental RNFL thickness seems to be a more reliable index. Deep structural alterations with OCT examination constitute an important indication of early functional changes, even if they are not still detected with achromatic perimetry. The MD index of VF seems to be more sensitive for the follow-up of patients with ocular hypertension.Keywords: glaucoma, ocular hypertension, OCT, visual fields, RNFL thicknes

Human pericardium graft in the management of bleb's complication performed in childhood: a case report

<p>Abstract</p> <p>Background</p> <p>To report a case with hypotony due to late leakage of the filtering bleb performed during childhood and treated surgically using human pericardium graft.</p> <p>Case Presentation</p> <p>A man with hypotony related to bleb's leakage in his right eye was presented. During his childhood trabeculectomy was performed to manage ocular hypertension due to pediatric glaucoma. Biomicroscopy revealed choroidal tissue incarcerated in the sclerectomy under the conjunctiva. Bleb revision was performed. Human pericardium graft was used to cover the sclerectomy and a new bleb with controlled outflow was created. The intraocular pressure (IOP) and Seidel test represent the main outcomes. Intraoperative and postoperative complications were recorded. Fifteen days postoperatively the IOP was of 7 mmHg and the bleb seemed to filter properly. Five months later the IOP was 9 mmHg and no complications were noticed. During the follow up time, the Seidel test was negative.</p> <p>Conclusion</p> <p>We used human pericardium graft with no complications in a case of bleb leakage performed for pediatric glaucoma.</p