Introdução e Objetivos: O sistema nervoso central (SNC) é o um sítio freqüente de recaída na criança com leucemia linfocítica aguda (LLA). Existe evidência de que a punção lombar traumática (PLT) pode representar um risco adicional de recaída no SNC quando ocorre inoculação de blastos no liqüido céfalorraquidiano (LCR). Este estudo tem por objetivo determinar se a ocorrência da PLT ao diagnóstico afeta o prognóstico de pacientes com essa patologia. Material e Métodos: Setenta e sete pacientes com diagnóstico de LLA, tratados entre 1992 a 2002, foram incluídos na análise. Quimioterapia intratecal (QIT) foi instilada imediatamente após a PL inicial (precoce), ou na segunda PL (tardia), realizada no período de 24 a 48 horas após a realização da PL inicial. Foi feita análise da influência da PLT e do momento (precoce x tardia) de administração da QIT em relação a recaída no SNC. Resultados: Entre os 19 pacientes que apresentaram PLT ao diagnóstico e receberam QIT tardia, seis tiveram recaída isolada no SNC e dois recaída combinada em SNC e medula óssea (MO). Entre os nove pacientes que tiveram PLT e receberam QIT precoce, somente um apresentou recaída combinada em SNC e MO (P=0,20); não houve, portanto, influência estatisticamente significativa da PLT na sobrevida livre de eventos (SLE) (55% para QIT precoce x 49% para QIT tardia) (P=0,37). Entretanto, em análise estratificada, de acordo com grupos de risco, observamos que para pacientes de baixo ou médio risco o OR foi de 0,8 quando recebiam QIT tardia (P=0,99) e 0,17 quando recebiam QIT precoce (P=0,47). Por outro lado, entre pacientes de alto risco o OR para recaída foi de 21,0 para aqueles que recebiam QIT tardia (P=0,09) e 1,5 para o grupo que recebia Q IT precoce (P=0,99). Conclusão: Os resultados do presente estudo são sugestivos de que a ocorrência da PLT tem uma influência adversa no prognóstico de pacientes com LLA de alto risco de recaída. Como estes resultados são decorrentes de um estudo retrospectivo, recomenda-se que sejam confirmados em estudos prospectivos randomizados. / Introduction and Objectives: The Central Nervous System (CNS) is a frequent site of relapse in childhood acute lymphoblastic leukemia (ALL). Traumatic lumbar puncture (TLP) is thought to increase the risk of relapse in the CNS. This study sought to determine if TLP at the time of diagnosis affected the outcome of patients. Matherial and Methods: Seventy-seven newly diagnosed patients treated from 1992 to 2002 were included in the analysis. Intrathecal therapy (IT) was instilled either immediately after the diagnostic LP (early) or at a second LP (delayed) 24 to 48 hours following the diagnostic LP procedure. The authors carried out an analysis of the influence of TLP and the timing (early versus late) of administration of IT therapy on CNS relapse. Results: Among the 19 patients who had a TLP at diagnosis and received late IT therapy, six had isolated CNS relapse and two had combined CNS and bone marrow (BM) relapse. Among the nine patients who had TLP and received early IT therapy, only one had a combined CNS and BM relapse (P=0.20); the influence of TLP was not statistically significant on the event-free survival (EFS) (55% for early IT versus 49% for delayed IT) ( P =0.37). However, when we carried out a stratified analysis according to risk categories we found that for low and standard risk patients the odds ratio (OR) for relapse was 0.8 for delayed IT therapy (P=0.99) and 0.17 for early IT (P=0.47). On the other hand, among high risk (HR) patients the OR for relapse was 21.0 for delayed IT therapy (P=0.09) and 1.5 for early IT (P=0.99). Conclusion: The occurrence of TLP impacts adversely on prognosis of HR ALL patients. As these results are based in a retrospective study with a low number of patients, the authors recommend future trials using prospective randomized studies to confirm these findings.

Introdução e Objetivos: O sistema nervoso central (SNC) é o um sítio freqüente de recaída na criança com leucemia linfocítica aguda (LLA). Existe evidência de que a punção lombar traumática (PLT) pode representar um risco adicional de recaída no SNC quando ocorre inoculação de blastos no liqüido céfalorraquidiano (LCR). Este estudo tem por objetivo determinar se a ocorrência da PLT ao diagnóstico afeta o prognóstico de pacientes com essa patologia. Material e Métodos: Setenta e sete pacientes com diagnóstico de LLA, tratados entre 1992 a 2002, foram incluídos na análise. Quimioterapia intratecal (QIT) foi instilada imediatamente após a PL inicial (precoce), ou na segunda PL (tardia), realizada no período de 24 a 48 horas após a realização da PL inicial. Foi feita análise da influência da PLT e do momento (precoce x tardia) de administração da QIT em relação a recaída no SNC. Resultados: Entre os 19 pacientes que apresentaram PLT ao diagnóstico e receberam QIT tardia, seis tiveram recaída isolada no SNC e dois recaída combinada em SNC e medula óssea (MO). Entre os nove pacientes que tiveram PLT e receberam QIT precoce, somente um apresentou recaída combinada em SNC e MO (P=0,20); não houve, portanto, influência estatisticamente significativa da PLT na sobrevida livre de eventos (SLE) (55% para QIT precoce x 49% para QIT tardia) (P=0,37). Entretanto, em análise estratificada, de acordo com grupos de risco, observamos que para pacientes de baixo ou médio risco o OR foi de 0,8 quando recebiam QIT tardia (P=0,99) e 0,17 quando recebiam QIT precoce (P=0,47). Por outro lado, entre pacientes de alto risco o OR para recaída foi de 21,0 para aqueles que recebiam QIT tardia (P=0,09) e 1,5 para o grupo que recebia Q IT precoce (P=0,99). Conclusão: Os resultados do presente estudo são sugestivos de que a ocorrência da PLT tem uma influência adversa no prognóstico de pacientes com LLA de alto risco de recaída. Como estes resultados são decorrentes de um estudo retrospectivo, recomenda-se que sejam confirmados em estudos prospectivos randomizados. / Introduction and Objectives: The Central Nervous System (CNS) is a frequent site of relapse in childhood acute lymphoblastic leukemia (ALL). Traumatic lumbar puncture (TLP) is thought to increase the risk of relapse in the CNS. This study sought to determine if TLP at the time of diagnosis affected the outcome of patients. Matherial and Methods: Seventy-seven newly diagnosed patients treated from 1992 to 2002 were included in the analysis. Intrathecal therapy (IT) was instilled either immediately after the diagnostic LP (early) or at a second LP (delayed) 24 to 48 hours following the diagnostic LP procedure. The authors carried out an analysis of the influence of TLP and the timing (early versus late) of administration of IT therapy on CNS relapse. Results: Among the 19 patients who had a TLP at diagnosis and received late IT therapy, six had isolated CNS relapse and two had combined CNS and bone marrow (BM) relapse. Among the nine patients who had TLP and received early IT therapy, only one had a combined CNS and BM relapse (P=0.20); the influence of TLP was not statistically significant on the event-free survival (EFS) (55% for early IT versus 49% for delayed IT) ( P =0.37). However, when we carried out a stratified analysis according to risk categories we found that for low and standard risk patients the odds ratio (OR) for relapse was 0.8 for delayed IT therapy (P=0.99) and 0.17 for early IT (P=0.47). On the other hand, among high risk (HR) patients the OR for relapse was 21.0 for delayed IT therapy (P=0.09) and 1.5 for early IT (P=0.99). Conclusion: The occurrence of TLP impacts adversely on prognosis of HR ALL patients. As these results are based in a retrospective study with a low number of patients, the authors recommend future trials using prospective randomized studies to confirm these findings.

Introdução e Objetivos: O sistema nervoso central (SNC) é o um sítio freqüente de recaída na criança com leucemia linfocítica aguda (LLA). Existe evidência de que a punção lombar traumática (PLT) pode representar um risco adicional de recaída no SNC quando ocorre inoculação de blastos no liqüido céfalorraquidiano (LCR). Este estudo tem por objetivo determinar se a ocorrência da PLT ao diagnóstico afeta o prognóstico de pacientes com essa patologia. Material e Métodos: Setenta e sete pacientes com diagnóstico de LLA, tratados entre 1992 a 2002, foram incluídos na análise. Quimioterapia intratecal (QIT) foi instilada imediatamente após a PL inicial (precoce), ou na segunda PL (tardia), realizada no período de 24 a 48 horas após a realização da PL inicial. Foi feita análise da influência da PLT e do momento (precoce x tardia) de administração da QIT em relação a recaída no SNC. Resultados: Entre os 19 pacientes que apresentaram PLT ao diagnóstico e receberam QIT tardia, seis tiveram recaída isolada no SNC e dois recaída combinada em SNC e medula óssea (MO). Entre os nove pacientes que tiveram PLT e receberam QIT precoce, somente um apresentou recaída combinada em SNC e MO (P=0,20); não houve, portanto, influência estatisticamente significativa da PLT na sobrevida livre de eventos (SLE) (55% para QIT precoce x 49% para QIT tardia) (P=0,37). Entretanto, em análise estratificada, de acordo com grupos de risco, observamos que para pacientes de baixo ou médio risco o OR foi de 0,8 quando recebiam QIT tardia (P=0,99) e 0,17 quando recebiam QIT precoce (P=0,47). Por outro lado, entre pacientes de alto risco o OR para recaída foi de 21,0 para aqueles que recebiam QIT tardia (P=0,09) e 1,5 para o grupo que recebia Q IT precoce (P=0,99). Conclusão: Os resultados do presente estudo são sugestivos de que a ocorrência da PLT tem uma influência adversa no prognóstico de pacientes com LLA de alto risco de recaída. Como estes resultados são decorrentes de um estudo retrospectivo, recomenda-se que sejam confirmados em estudos prospectivos randomizados. / Introduction and Objectives: The Central Nervous System (CNS) is a frequent site of relapse in childhood acute lymphoblastic leukemia (ALL). Traumatic lumbar puncture (TLP) is thought to increase the risk of relapse in the CNS. This study sought to determine if TLP at the time of diagnosis affected the outcome of patients. Matherial and Methods: Seventy-seven newly diagnosed patients treated from 1992 to 2002 were included in the analysis. Intrathecal therapy (IT) was instilled either immediately after the diagnostic LP (early) or at a second LP (delayed) 24 to 48 hours following the diagnostic LP procedure. The authors carried out an analysis of the influence of TLP and the timing (early versus late) of administration of IT therapy on CNS relapse. Results: Among the 19 patients who had a TLP at diagnosis and received late IT therapy, six had isolated CNS relapse and two had combined CNS and bone marrow (BM) relapse. Among the nine patients who had TLP and received early IT therapy, only one had a combined CNS and BM relapse (P=0.20); the influence of TLP was not statistically significant on the event-free survival (EFS) (55% for early IT versus 49% for delayed IT) ( P =0.37). However, when we carried out a stratified analysis according to risk categories we found that for low and standard risk patients the odds ratio (OR) for relapse was 0.8 for delayed IT therapy (P=0.99) and 0.17 for early IT (P=0.47). On the other hand, among high risk (HR) patients the OR for relapse was 21.0 for delayed IT therapy (P=0.09) and 1.5 for early IT (P=0.99). Conclusion: The occurrence of TLP impacts adversely on prognosis of HR ALL patients. As these results are based in a retrospective study with a low number of patients, the authors recommend future trials using prospective randomized studies to confirm these findings.

Introdução: Procedimentos dolorosos de curta duração como o aspirado/biópsia de medula óssea e a punção lombar, com ou sem quimioterapia intratecal, são realizados com freqüência durante o tratamento de crianças com câncer. Estudos examinando diversos métodos de sedação para crianças submetidas aos procedimentos dolorosos têm mostrado diferentes resultados. Enquanto alguns investigadores sugerem que benzodiazepínicos e outras drogas intravenosas são eficazes, outros recomendam anestesia geral breve como sendo superior a todos outros modos de sedação O objetivo desde estudo é descrever a freqüência e a severidade das complicações da AMO/BMO e da PL sob anestesia geral. Pacientes e métodos: Um estudo observacional prospectivo foi realizado de Novembro de 2003 a Agosto de 2005. Pacientes com câncer e idade menor ou igual a 21 anos, em tratamento no Serviço de Oncologia Pediátrica do Hospital de Clínicas de Porto Alegre, submetidos a procedimentos de curta duração, diagnósticos e/ou terapêuticos, sob anestesia geral, no Centro Cirúrgico Ambulatorial. Resultados: Cento e trinta e sete pacientes foram submetidos a 423 procedimentos sob anestesia geral. Eram do sexo masculino 61%, com média de idade de 7,5 anos (0,2 a 21) e ASA II 98%. Oitenta e sete por cento dos procedimentos foram realizados em pacientes com leucemia ou linfoma. A maioria dos procedimentos não determinou eventos adversos durante os períodos intra-operatório e pós-operatório. Nenhum procedimento foi suspenso após iniciado. Um paciente teve dor lombar após o procedimento e foi internado com suspeita de hematoma subdural, o que foi descartado. Nenhum paciente necessitou reanimação cardiopulmonar ou tratamento em unidade de terapia intensiva. CONCLUSÃO: A anestesia geral para procedimentos dolorosos de curta duração, em crianças que realizam tratamento para neoplasias malignas, é segura quando realizada em centro cirúrgico ambulatorial por profissionais treinados. / Introduction: Painful short duration procedures like bone marrow aspiration/biopsy and the lumbar puncture with or without intrathecal chemotherapy are frequently performed during the treatment of children with cancer. Studies examining different methods of sedation for children undergoing painful procedures have shown different results. While some investigators suggest that benzodiapines and other intravenous drugs are efficacious, others recommend brief general anesthesia as being superior to all other modes of sedation. The objective of this study is to evaluate the frequency and severity of complications of BMA/BMB and LP under general anesthesia. Patients and methods: Prospective observational study performed from November 2003 to August 2005. Patients with cancer younger than 21 years old, receiving treatment at the Pediatric Oncology Unity of Hospital de Clínicas de Porto Alegre, undergoing diagnostic and/or therapeutic short duration procedures carried out under general anesthesia in the outpatient surgical unit. Results: One hundred and thirty seven patients were submitted to 423 procedures under general anesthesia. There were 61% boys, mean age of 7.5 years (0.2-21) and ASA II 98%. Eighty seven percent of the procedures were carried out in patients with leukemia or lymphoma. The majority of the procedures had no adverse events during intraoperative and postoperative periods. No procedure had to be suspended after it had begun. One patient had lumbar pain after procedure and was admitted to the ward with suspected subdural bleeding, but this was not confirmed. No patient needed cardiopulmonary reanimation or treatment in the intensive care unit. CONCLUSION: General anesthesia for short duration painful procedures in children undergoing treatment for malignancies is safe when carried out by trained professionals in outpatient surgical unit.

Introdução: Procedimentos dolorosos de curta duração como o aspirado/biópsia de medula óssea e a punção lombar, com ou sem quimioterapia intratecal, são realizados com freqüência durante o tratamento de crianças com câncer. Estudos examinando diversos métodos de sedação para crianças submetidas aos procedimentos dolorosos têm mostrado diferentes resultados. Enquanto alguns investigadores sugerem que benzodiazepínicos e outras drogas intravenosas são eficazes, outros recomendam anestesia geral breve como sendo superior a todos outros modos de sedação O objetivo desde estudo é descrever a freqüência e a severidade das complicações da AMO/BMO e da PL sob anestesia geral. Pacientes e métodos: Um estudo observacional prospectivo foi realizado de Novembro de 2003 a Agosto de 2005. Pacientes com câncer e idade menor ou igual a 21 anos, em tratamento no Serviço de Oncologia Pediátrica do Hospital de Clínicas de Porto Alegre, submetidos a procedimentos de curta duração, diagnósticos e/ou terapêuticos, sob anestesia geral, no Centro Cirúrgico Ambulatorial. Resultados: Cento e trinta e sete pacientes foram submetidos a 423 procedimentos sob anestesia geral. Eram do sexo masculino 61%, com média de idade de 7,5 anos (0,2 a 21) e ASA II 98%. Oitenta e sete por cento dos procedimentos foram realizados em pacientes com leucemia ou linfoma. A maioria dos procedimentos não determinou eventos adversos durante os períodos intra-operatório e pós-operatório. Nenhum procedimento foi suspenso após iniciado. Um paciente teve dor lombar após o procedimento e foi internado com suspeita de hematoma subdural, o que foi descartado. Nenhum paciente necessitou reanimação cardiopulmonar ou tratamento em unidade de terapia intensiva. CONCLUSÃO: A anestesia geral para procedimentos dolorosos de curta duração, em crianças que realizam tratamento para neoplasias malignas, é segura quando realizada em centro cirúrgico ambulatorial por profissionais treinados. / Introduction: Painful short duration procedures like bone marrow aspiration/biopsy and the lumbar puncture with or without intrathecal chemotherapy are frequently performed during the treatment of children with cancer. Studies examining different methods of sedation for children undergoing painful procedures have shown different results. While some investigators suggest that benzodiapines and other intravenous drugs are efficacious, others recommend brief general anesthesia as being superior to all other modes of sedation. The objective of this study is to evaluate the frequency and severity of complications of BMA/BMB and LP under general anesthesia. Patients and methods: Prospective observational study performed from November 2003 to August 2005. Patients with cancer younger than 21 years old, receiving treatment at the Pediatric Oncology Unity of Hospital de Clínicas de Porto Alegre, undergoing diagnostic and/or therapeutic short duration procedures carried out under general anesthesia in the outpatient surgical unit. Results: One hundred and thirty seven patients were submitted to 423 procedures under general anesthesia. There were 61% boys, mean age of 7.5 years (0.2-21) and ASA II 98%. Eighty seven percent of the procedures were carried out in patients with leukemia or lymphoma. The majority of the procedures had no adverse events during intraoperative and postoperative periods. No procedure had to be suspended after it had begun. One patient had lumbar pain after procedure and was admitted to the ward with suspected subdural bleeding, but this was not confirmed. No patient needed cardiopulmonary reanimation or treatment in the intensive care unit. CONCLUSION: General anesthesia for short duration painful procedures in children undergoing treatment for malignancies is safe when carried out by trained professionals in outpatient surgical unit.

Introdução: Procedimentos dolorosos de curta duração como o aspirado/biópsia de medula óssea e a punção lombar, com ou sem quimioterapia intratecal, são realizados com freqüência durante o tratamento de crianças com câncer. Estudos examinando diversos métodos de sedação para crianças submetidas aos procedimentos dolorosos têm mostrado diferentes resultados. Enquanto alguns investigadores sugerem que benzodiazepínicos e outras drogas intravenosas são eficazes, outros recomendam anestesia geral breve como sendo superior a todos outros modos de sedação O objetivo desde estudo é descrever a freqüência e a severidade das complicações da AMO/BMO e da PL sob anestesia geral. Pacientes e métodos: Um estudo observacional prospectivo foi realizado de Novembro de 2003 a Agosto de 2005. Pacientes com câncer e idade menor ou igual a 21 anos, em tratamento no Serviço de Oncologia Pediátrica do Hospital de Clínicas de Porto Alegre, submetidos a procedimentos de curta duração, diagnósticos e/ou terapêuticos, sob anestesia geral, no Centro Cirúrgico Ambulatorial. Resultados: Cento e trinta e sete pacientes foram submetidos a 423 procedimentos sob anestesia geral. Eram do sexo masculino 61%, com média de idade de 7,5 anos (0,2 a 21) e ASA II 98%. Oitenta e sete por cento dos procedimentos foram realizados em pacientes com leucemia ou linfoma. A maioria dos procedimentos não determinou eventos adversos durante os períodos intra-operatório e pós-operatório. Nenhum procedimento foi suspenso após iniciado. Um paciente teve dor lombar após o procedimento e foi internado com suspeita de hematoma subdural, o que foi descartado. Nenhum paciente necessitou reanimação cardiopulmonar ou tratamento em unidade de terapia intensiva. CONCLUSÃO: A anestesia geral para procedimentos dolorosos de curta duração, em crianças que realizam tratamento para neoplasias malignas, é segura quando realizada em centro cirúrgico ambulatorial por profissionais treinados. / Introduction: Painful short duration procedures like bone marrow aspiration/biopsy and the lumbar puncture with or without intrathecal chemotherapy are frequently performed during the treatment of children with cancer. Studies examining different methods of sedation for children undergoing painful procedures have shown different results. While some investigators suggest that benzodiapines and other intravenous drugs are efficacious, others recommend brief general anesthesia as being superior to all other modes of sedation. The objective of this study is to evaluate the frequency and severity of complications of BMA/BMB and LP under general anesthesia. Patients and methods: Prospective observational study performed from November 2003 to August 2005. Patients with cancer younger than 21 years old, receiving treatment at the Pediatric Oncology Unity of Hospital de Clínicas de Porto Alegre, undergoing diagnostic and/or therapeutic short duration procedures carried out under general anesthesia in the outpatient surgical unit. Results: One hundred and thirty seven patients were submitted to 423 procedures under general anesthesia. There were 61% boys, mean age of 7.5 years (0.2-21) and ASA II 98%. Eighty seven percent of the procedures were carried out in patients with leukemia or lymphoma. The majority of the procedures had no adverse events during intraoperative and postoperative periods. No procedure had to be suspended after it had begun. One patient had lumbar pain after procedure and was admitted to the ward with suspected subdural bleeding, but this was not confirmed. No patient needed cardiopulmonary reanimation or treatment in the intensive care unit. CONCLUSION: General anesthesia for short duration painful procedures in children undergoing treatment for malignancies is safe when carried out by trained professionals in outpatient surgical unit.

Il n'existe pas de méthode non invasive validée pour déterminer la valeur absolue de la pression intracrânienne (PIC). Le liquide céphalorachidien (LCS) et le liquide cochléaire sont reliés par l'aqueduc cochléaire. Le but de ce projet est d'utiliser l'absorbance de l'oreille, optimale lorsque les structures vibrantes sont en position de repos, de sorte que les étriers lorsque la pression à l'extérieur de l'oreille (dans le conduit auditif externe -P_cae ) contrarie la PIC par les osselets de l'oreille moyenne. Les sujets ont été testés dans différentes positions d'inclinaison du corps, ce qui augmente la PIC, à l'aide d'un tympanomètre à large bande. 78 oreilles (sujets témoins entre 20 et 30 ans) ont montré que l'absorbance est maximale à toutes les fréquences à P_cae = 0 mmH2O en position début, elle diminue de façon complexe à P_cae zéro, mais à nouveau identique l'absorbance maximale à P_cae = 13 mm H2O ± 7 en position allongée, et 23 mm H2O ± 14 en position Trendelenburg (-30°), en 68 oreilles sur 78. Les 10 oreilles restantes présentaient un dysfonctionnement anatomique. Un modèle physique a été établi à partir d'un modèle d'oreille électromécanique classique, qui reproduit le comportement observé en attribuant à la PIC la cause des changements d'absorbance et en prédisant la capacité du P_cae pour compenser les changements d'absorbance dus à la PIC. De plus, 3 patients traités par un test de perfusion ont été testés, ainsi que 2 patients traités par ponction lombaire. Ces patients ont montré l'effet de la pression positive et négative dans les courbes d'absorbance. La littérature permet d'établir une corrélation entre la PIC absolue (dans chaque position du corps) et l'absorbance, nous pouvons conclure qu'en raison de la géométrie de l'oreille moyenne, la relation d'équilibre entre les valeurs absolues est PIC = 15 x P_cae , où 15 est le rapport des surfaces entre la MT et la platine de l’étrier. Des sujets suivis par une mesure invasive de la PIC seront nécessaires pour la continuation de cette étude. / There is no validated non-invasive method for determining the absolute value of intracranial pressure (ICP). Ear connect cerebrospinal fluid (CSF) and cochlear fluid via cochlear aqueduct. The goal of this project is to use ear absorbance, optimal when the vibrating structures are in resting position, so the stapes when the pressure outside the ear (in the external ear canal -Peec) counteracts the ICP through the middle ear ossicles. Subjects are testing in different tilt body position, which increase ICP, using a tympanometer Wideband. 78 ears of control subjects between 20 and 30 years have shown that the absorbance is maximum at all frequencies at Peec = 0 mmH2O in standing posture, decreases in a complex way at zero Peec, but again identical to the maximum absorbance at Peec = 13 mm H2O ± 7 in supine, and 23 mm H2O ± 14 in Trendelenburg posture (-30 °), this in 68 ears out of 78. The remaining 10 ears had an anatomical dysfunction. A physical model was established from a classical electromechanical ear model, which reproduces the observed behavior by attributing to the ICP the cause of changes in absorbance and predicting the ability for Peec to offset the absorbance changes due to ICP. Furthermore, 3 patients treated with a perfusion test were tested as well as 2 patients treated by a lumbar puncture. These patients showed the effect of positives and negatives pressure in absorbance curves. Literature make possible a correlation between absolute ICP (in every tilt body position) and absorbance, we can conclude that due to the geometry of the middle ear, the equilibrium relationship between absolute values is ICP = 15 x Peec, where 15 is the ratio of the areas between the tympanic membrane and the stape plate. Subjects tested by invasive measurement of ICP will be required for the continuation of this study.

Efficient and accurate sensing of various parameters is needed for numerous applications. In this regard, different categories of sensors play a significant role and different applications require diverse sensing mechanisms owing to the operating conditions and field constraints. Among the several sensor methodologies available, optical fiber sensors have found significant attention, because of their advantages such as negligible foot print, small mass, immunity to Electromagnetic Interference, etc. In the category of optical fiber sensors, Fiber Bragg Grating (FBG) sensors have found importance in many fields such as health monitoring of civil structures, environmental monitoring involving gas & humidity sensing, monitoring parameters like pressure, tilt, displacement, etc. In the recent times, FBGs have found applications in biomedical, biomechanical and biosensing fields. A FBG is a periodic change of the refractive index of the core of a single mode optical fiber along its longitudinal axis. The periodic modulation in the index of refraction is obtained by exposing a photosensitive germanium-doped silica fiber to an intense UV laser beam. FBGs, in the basic form, can sense strain and temperature. However, in recent years, several newer sensing applications of FBGs have been demonstrated. Some of the main features of the FBG sensor which qualify them for diverse sensing applications are high sensitivity, large operational bandwidth, multiplexing & multi modal sensing capability, etc. In this thesis work, FBG sensor based devices have been developed for newer applications in bio-medical fields for the measurement of force, flow and temperature. Particularly, novel transduction methodologies have been proposed, in order to convert the measurand parameter into a secondary parameter that can be sensed by the FBG sensor. The evaluation of the force required for a spinal needle to penetrate various tissue layers from skin to the epidural space is vital. In this work, a novel technique for dynamic monitoring of force experienced by a spinal needle during lumbar puncture using Fiber Bragg Grating (FBG) sensor has been developed. The Fiber Bragg Grating Force Device (FBGFD) developed, measures the force on the spinal needle due to varied resistance offered by different tissue layers during its traversal. The effect of gauge of the spinal needle used for the lumbar puncture procedure affects the force required for its insertion into the tissue. The FBGFD developed, has been further utilized for a comparative study of the force required for lumbar puncture of various tissue layers with spinal needle of different gauges. The results obtained may serve as a guideline for selection of suitable gauge spinal needle during lumbar puncture minimizing post puncture side effects on patients. The pulmonary function test carried out using a spirometer, provides vital information about the functional status of the respiratory system of the subject. A Fiber Bragg Grating Spirometer (FBGS) has been developed which has the ability to convert the rate of air flow into a shift in wavelength that can be acquired by the FBG sensor. The FBGS can dynamically acquire the complete breathing sequence comprising of the inhalation phase, pause phase and exhalation phase in terms of the air flow rate along with the time duration of each phase. Methods are adopted to analyse and determine important pulmonary parameters using FBGS and compare these parameters with those obtained with a commercially available hospital grade pneumotachograph spirometer. Thermal imaging is one of the emerging non-invasive neuro-imaging techniques which can potentially indicate the boundaries of a brain tumor. The variation in tissue surface temperature is indicative of a tumor existence. In this work a FBG temperature sensor (FBGTS) has been developed for thermography of a simulated tissue using Agar material. The temperature of the embedded heater which mimics a brain tumor along with the surface temperature of the tissue model, is acquired using FBGTSs simultaneously. Further, the surface temperatures are studied for varying heater temperatures as well as varying positions of the heater in the simulated tissue model. To conclude, FBG based devices have been developed in this work, for applications in biomedical domain, with appropriate transduction methodologies for sensing different parameters such as force, flow and temperature.