Gonzalo Díaz

Effects of Prone Positioning on Lung Protection in Patients with Acute Respiratory Distress Syndrome

RATIONALE Positive end-expiratory pressure (PEEP) and prone positioning may induce lung recruitment and affect alveolar dynamics in acute respiratory distress syndrome (ARDS). Whether there is interdependence between the effects of PEEP and prone positioning on these variables is unknown. OBJECTIVES To determine the effects of high PEEP and prone positioning on lung recruitment, cyclic recruitment/derecruitment, and tidal hyperinflation and how these effects are influenced by lung recruitability. METHODS Mechanically ventilated patients (Vt 6 ml/kg ideal body weight) underwent whole-lung computed tomography (CT) during breath-holding sessions at airway pressures of 5, 15, and 45 cm H2O and Cine-CTs on a fixed thoracic transverse slice at PEEP 5 and 15 cm H2O. CT images were repeated in supine and prone positioning. A recruitment maneuver at 45 cm H2O was performed before each PEEP change. Lung recruitability was defined as the difference in percentage of nonaerated tissue between 5 and 45 cm H2O. Cyclic recruitment/de-recruitment and tidal hyperinflation were determined as tidal changes in percentage of nonaerated and hyperinflated tissue, respectively. MEASUREMENTS AND MAIN RESULTS Twenty-four patients with ARDS were included. Increasing PEEP from 5 to 15 cm H2O decreased nonaerated tissue (501 ± 201 to 322 ± 132 grams; P < 0.001) and increased tidal-hyperinflation (0.41 ± 0.26 to 0.57 ± 0.30%; P = 0.004) in supine. Prone positioning further decreased nonaerated tissue (322 ± 132 to 290 ± 141 grams; P = 0.028) and reduced tidal hyperinflation observed at PEEP 15 in supine patients (0.57 ± 0.30 to 0.41 ± 0.22%). Cyclic recruitment/de-recruitment only decreased when high PEEP and prone positioning were applied together (4.1 ± 1.9 to 2.9 ± 0.9%; P = 0.003), particularly in patients with high lung recruitability. CONCLUSIONS Prone positioning enhances lung recruitment and decreases alveolar instability and hyperinflation observed at high PEEP in patients with ARDS.

Comparison of the Clinical Efficacy of Two Different Immunosuppressive Regimens in Patients with Chronic Vogt-Koyanagi-Harada Disease

Purpose: To prospectively compare 2 immunosupressive regimens in patients with active Vogt-Koyanagi-Harada disease in spite of systemic glucocorticoid treatment. Methods: Forty-four patients were diagnosed between 1998 and 2005. Twenty-one developed chronic intraocular inflammation in spite of glucocorticoid treatment and were randomized to receive either prednisone and azathioprine (AZA) (n = 12) or prednisone and cyclosporine (CyA) (n = 9). Results: In the AZA group Tyndall score decreased from 1.21 ± 1.10 to 0.29 ± 0.62 (p < .01), and visual acuity (LogMAR) improved from 0.32 ± 0.35 to 0.09 ± 0.16 (p < .001). In the CyA group Tyndall score decreased from 1.67 ± 1.08 to 0.16 ± 0.51 (p < .001), and visual acuity improved from 0.41 ± 0.40 to 0.25 ± 0.42 (p < .001). Patients in the AZA group needed a significantly higher average prednisone dose and total cumulative dose than those in the CyA group, p < .01 for each comparison. Conclusions: Both regimens showed a good clinical efficacy, but CyA seems to be a better glucocorticoid-sparing agent than AZA.

Eficacia del infliximab en pacientes con síndrome de Behçet portadores de úveo-retinitis grave

The efficacy and safety of repeated administration of infliximabwas evaluated in five patients (two men, three women) with Behcet syndrome accompanied bysevere uveoretinitis. Ocular and extra ocular inflammation was suppressed in all patientsduring the observation period without any serious adverse reactions. The results in thesepatients suggests that TNF-

Enfermedad de Behçet en Chile: Análisis clínico de 44 casos

12 years. According to BDCJ criteria, 13 patients had complete BD, 24 hadincomplete BD and 7 had a suspected BD. Thirty two patients fulfilled the ISG criteria. Forty twopatients (95%) had oral ulcers, 33 (75%) had genital ulcers and 29 (66%) hadophthalmological involvement. Eleven and three patients had symptoms of central andperipheral nervous system involvement, respectively. No gender differences were detected.

Effects of Phaeomoniella chlamydospora ana Phaeoacremonium aleophilum on grapevine rootstocks

G. A. Diaz, M. Esterio, and J. Auger. 2009. Effects of Phaeomoniella chlamydospora and Phaeoacremonium aleophilum on grapevine rootstocks. Cien. Inv. Agr. 36(3):381-390. Cuttings of fi ve grapevine (Vitis vinifera) rootstocks were wounded and immediately inoculated with suspensions (approximately 5x10 3 conidia·mL -1 ) of either Phaeomoniella chlamydospora, Phaeoacremonium aleophilum or a mixture of both species. The presence of these endophyte fungi affected the quality of each of the fi ve rootstocks. Among the roostocks investigated in this study, 1103P and 101-14 MG were less susceptible to the infection caused by Pa. chlamydospora and Pm. aleophillum.

High-volume hemofiltration and prone ventilation in subarachnoid hemorrhage complicated by severe acute respiratory distress syndrome and refractory septic shock

Como Cornejo et al. observaram, essas duas tecnicas sao desafiadoras e necessitam de um ava-liacao caso a caso para tomada de decisao. Devem ser considerados os possiveis efeitos adversos dessas tecnicas. Uma metanalise mostra que “nao ha um efeito benefico global claro” quando se compara a hemofiltracao de alto volume com a hemofiltracao com volume padrao.We would like to discuss the publication “High-volume hemofiltration and prone ventilation”.(1) Cornejo et al. reported the use of the combination of these two novel approaches for the management of subarachnoid hemorrhage that is complicated by severe acute respiratory distress syndrome.(1) As Cornejo et al. noted, these two techniques are very challenging and require case by case decision making. There must be consideration of the possible adverse effects of these techniques. A meta-analysis shows that there is “no clear overall beneficial effect” when high-volume hemofiltration is compared to standard volume hemofiltration.(2) Some reports mention the adjustment of cytokine biological processes as the possible responsible factor, whereas other reports do not agree with that hypothesis.(2) In the present case report by Cornejo et al., the reason for the occurrence of septic shock remains unclear. Based on the patient’s available history, it seems that there is no laboratory confirmation of sepsis. Additionally, there is no evidence of cytokine biological process adjustment reported in the present article. In general, due to the uncertainties about the exact biological effect of high-volume hemofiltration, the beneficial effects of this procedure remain unconfirmed in septic shock.(3) Regarding prone positioning, the complication and side effect of the procedure can still be observed.(4) Cardiac arrest immediately after prone positioning is also reported.(5) In the present case report, the use of prone positioning might be valid, and the success of cardiac monitoring is established. Interestingly, 72 hours of prone positioning were required for adjustment of the pressure. This long period might be sufficient for self-adjustment of the patient’s intracranial pressure, due to the neurological improvement after manipulation or other additional procedures for the management of pressure, without the need of a special positioning procedure. The improvement of the patient might be due to the successful control of the neurological problem and might not be related to the use of high-volume hemofiltration plus prone positioning.

Eficacia de la azatioprina en la enfermedad ocular inflamatoria no infecciosa resistente a tratamiento esteroidal sistémico

Background: Topical and systemic steroids are the first line of treatment of non infectious inflammatory ocular disease. Immunosuppresants are reserved as a second line treatment. Aim: To evaluate the role of Azathioprine (AZA) as a coadyuvant immunosuppressive treatment for non infectious ocular inflammatory diseases (OIDs) resistant to systemic steroid therapy in a retrospective, noncomparative interventional case series. Patients and methods: Patients using oral Prednisone due to an active or recurrent OID, without clinical response, and not receiving any other immunosuppressive treatment were studied. A standard protocol of oral Prednisone (0.5 mg/kg/ day) and oral AZA (2-3 mg/kg/day) during one year was used. Ocular and systemic monthly evaluations were done including relapse rate, steroid dosage, inflammatory score and visual acuity. Results: Thirty patients (10 male) aged 18-75 years (mean 44 years) were studied. Three had bilateral anterior uveitis, one had pars planitis, four had diffuse uveitis, eight Vogt-Koyanahi-Harada syndrome, three Behcet’s disease, three necrotizing scleritis and eight had retinochoroidopathy. A complete initial response was observed in 26 patients (87%). The time of response was between 1 to 6 months (mean 2.65 months). Seventeen percent of these had a relapse 6 to 12 months after AZA was started. In 61%, visual acuity improved. The ocular inflammatory score decreased in 86.5%. Eleven patients had mild controlled side effects that did not require discontinuation of AZA. Conclusions: Combined systemic steroid and oral AZA therapy is safe and effective in controlling steroid resistant non infectious inflammatory ocular diseases (Rev Med Chile 2007; 135: 702-7). (Key words: Azathioprine; Prednisone; Uveitis; Vogt-Koyanagi-Harada Syndrome)

Hemofiltração de alto volume e ventilação em posição prona em hemorragia subaracnóidea complicada por grave síndrome do desconforto respiratório agudo e choque séptico refratário.

Relatamos o tratamento bem-suce- dido de dois pacientes com hemorragia subaracnoidea complicada com grave falencia respiratoria e choque septico refratario, utilizando, simultaneamente, ventilacao em posicao prona e hemofil - tracao de alto volume. Esses tratamentos de resgate permitiram que os pacientes superassem a grave situacao sem com- plicacoes associadas ou efeitos deleterios na pressao intracraniana e de perfusao cerebral. A ventilacao em posicao pro- na e, hoje, um tratamento aceito para sindrome de desconforto respiratorio agudo grave, e a hemofiltracao de alto volume e um suporte hemodinâmico nao convencional, que tem diversosWe report the successful treatment of two patients with aneurismal subarachnoid hemorrhage complicated by severe respiratory failure and refractory septic shock using simultaneous prone position ventilation and high-volume hemofiltration. These rescue therapies allowed the patients to overcome the critical situation without associated complications and with no detrimental effects on the intracranial and cerebral perfusion pressures. Prone position ventilation is now an accepted therapy for severe acute respiratory distress syndrome, and high-volume hemofiltration is a non-conventional hemodynamic support that has several potential mechanisms for improving septic shock. In this manuscript, we briefly review these therapies and the related evidence. When other conventional treatments are insufficient for providing safe limits of oxygenation and perfusion as part of basic neuroprotective care in subarachnoid hemorrhage patients, these rescue therapies should be considered on a case-by-case basis by an experienced critical care team.

Analysis and Classification of Natural Rock Textures based on New Transform-based Features

This work develops a mathematical method to extract relevant information about natural rock textures to address the problem of automatic classification. Classical methods of texture analysis cannot be directly applied in this context, since rock textures are typically characterized by both stationary patterns (a classic kind of texture) and geometric forms, which are not properly captured with conventional methods. Due to the presence of these two phenomena, a new classification approach is proposed in which each rock texture class is individually analyzed developing a specific low-dimensional discriminative feature. For this task, multi-scale transform domain representations are adopted, allowing the analysis of the images at several levels of scale and orientation. The proposed method is applied to a database of digital photographs acquired in a porphyry copper mining project, showing better performance than state-of-the-art techniques, and additionally presenting a low computational cost.

Estudio comparativo de variables clínicas y costo de la técnica quirúrgica de histerectomía por vía abdominal y laparoscópica

The purpose of the present study is to compare clinical and economic outcomes of abdominal versus laparoscopic hysterectomy. The study design was retrospective and observational, and it was conducted on 1.663 patients aged between 27 and 83 undergoing hysterectomy for benign gynecologic conditions between 1997-2005, at the Hospital Clinico of the University of Chile. Of the 1.663 surgeries, 11,36% were laparoscopic hysterectomies and 88,63% accounted for abdominal hysterectomies. The global complication rate was 42,8%for abdominal hysterectomy and 16,4% for laparoscopic hysterectomy. Laparoscopic hysterectomy offers advantages such as a fewer complications and a shorter hospital stay when compared to abdominal hysterectomy. However, its cost is significantly higher than that of the abdominal approach.