Effect of exercise intensity and apnea on splenic contraction and hemoglobin increase in well-trained cross-country skiers.

The human spleen acts as a reservoir for red blood cells, which is mobilized into the systemic circulation during various conditions such as hypoxia and physical exertion. Cross-country (XC) skiers, renowned for their exceptional aerobic capacity, are regularly exposed to high-intensity exercise and local oxygen deficits. We investigated a putative dose-dependent relationship between splenic contraction and concomitant hemoglobin concentration ([Hb]) elevation across four exercise intensities in well-trained XC skiers. Fourteen male XC skiers voluntarily participated in a 2-day protocol, encompassing a serial apnea test and a [Formula: see text]O2max test (day 1), followed by three submaximal exercise intensities on a roller skiing treadmill corresponding to 55, 70, and 85% of [Formula: see text]O2max (day 2). Spleen volume was measured via ultrasonic imaging, and venous blood samples were used to determine [Hb] levels. Baseline spleen volume was similar (266(35) mL) for all conditions (NS). Notably, all conditions induced significant splenic contractions and transient [Hb] elevations. The [Formula: see text]O2max test exhibited the most pronounced splenic contraction (35.8%, p < 0.001) and a [Hb] increase of 8.1%, while the 85% exercise intensity led to 27.1% contraction and the greatest [Hb] increase (8.3%, < 0.001) compared to baseline. The apnea test induced relatively smaller responses (splenic contraction: 20.4%, [Hb] = 3.3%, p < 0.001), akin to the response observed at the 70% exercise intensity (splenic contraction = 23%, [Hb] = 6.4%, p < 0,001) and 55% (splenic contraction = 20.0%, [Hb] = 4.8%, p < 0.001). This study shows a discernible dose-dependent relationship between splenic contraction and [Hb] increase with levels of exercise, effectively distinguishing between submaximal and maximal exercise intensity.

Effects of hyperventilation on oxygenation, apnea breaking points, diving response, and spleen contraction during serial static apneas.

PURPOSE: Hyperventilation is considered a major risk factor for hypoxic blackout during breath-hold diving, as it delays the apnea breaking point. However, little is known about how it affects oxygenation, the diving response, and spleen contraction during serial breath-holding. METHODS: 18 volunteers with little or no experience in freediving performed two series of 5 apneas with cold facial immersion to maximal duration at 2-min intervals. In one series, apnea was preceded by normal breathing and in the other by 15 s of hyperventilation. End-tidal oxygen and end-tidal carbon dioxide were measured before and after every apnea, and peripheral oxygen saturation, heart rate, breathing movements, and skin blood flow were measured continuously. Spleen dimensions were measured every 15 s. RESULTS: Apnea duration was longer after hyperventilation (133 vs 111 s). Hyperventilation reduced pre-apnea end-tidal CO2 (17.4 vs 29.0 mmHg) and post-apnea end-tidal CO2 (38.5 vs 40.3 mmHg), and delayed onset of involuntary breathing movements (112 vs 89 s). End-tidal O2 after apnea was lower in the hyperventilation trial (83.4 vs 89.4 mmHg) and so was the peripheral oxygen saturation nadir after apnea (90.6 vs 93.6%). During hyperventilation, the nadir peripheral oxygen saturation was lower in the last apnea than in the first (94.0% vs 86.7%). There were no differences in diving response or spleen volume reduction between conditions or across series. CONCLUSIONS: Serial apneas  revealed a previously undescribed aspect of hyperventilation; a progressively increased desaturation across the series, not observed after normal breathing and could heighten the risk of a blackout.

Case Studies in Physiology: Is blackout in breath-hold diving related to cardiac arrhythmias?

Syncope or "blackout" (BO) in breath-hold diving (freediving) is generally considered to be caused by hypoxia. However, it has been suggested that cardiac arrhythmias affecting the pumping effectivity could contribute to BO. BO is fairly common in competitive freediving, where athletes aim for maximal performance. We recorded heart rate (HR) during a static apnea (STA) competition, to reveal if arrhythmias occur. Four male freedivers with STA personal best (PB) of 349 ± 43 s, volunteered during national championships, where they performed STA floating face down in a shallow indoor pool. A non-coded Polar T31 chest strap recorded R-R intervals and a water- and pressure-proof pulse oximeter arterial oxygen saturation. Three divers produced STA near their PB without problems, whereas one diver ended with BO at 5 min 17s, which was 12 s beyond his PB. He was immediately brought up by safety divers and resumed breathing within 10 s. All divers attained similar lowest diving HR (47 ± 4 beats/min), but HR recordings displayed a different pattern for the diver ending with BO. After a short tachycardia, the three successful divers developed bradycardia, which became more pronounced during the second half of the apnea. The fourth diver developed pronounced bradycardia earlier, and at 2.5 min into the apnea, HR started alternating between approximately 50 and 140 beats/min, until the diver lost consciousness. At resumed breathing, HR returned to baseline. Nadir oxygen saturation was similar for all divers. We speculate that arrhythmia could have contributed to BO, by lowering stroke volume leading to a systolic blood pressure drop, affecting brain perfusion.NEW & NOTEWORTHY Heart rate during prolonged breath-holding until the point of loss of consciousness has not previously been published. The recordings show that blackout was preceded by a period of persistent alterations in R-R intervals, whereby an ectopic beat followed every normal heartbeat. Explanations for this deviating heart rate pattern could be either premature atrial contractions or premature ventricular contractions following every atrial beat, i.e., bigeminy, which could have compromised cardiac pumping function and caused/contributed to blackout.

Test-retest reliability of splenic volume assessment by ultrasonography.

While MRI and CT are the gold standards for assessments of splenic size in clinical settings, ultrasonography is particularly suited due to its portability, cost efficiency and easy utilization. However, ultrasonography is associated with subjective assessment, potentially resulting in increased variation. We used a test-retest design aiming to determine the reliability of splenic measurements assessed by ultrasonography during apnea. In addition, we compared reliability between different equations for volume calculations: Koga, Prolate ellipsoid and Pilström. Twelve healthy participants (6 women) performed two tests separated by 15 min, comprising a maximal voluntary apnea in a seated position. Splenic dimensions were measured via ultrasonography for 5 min before and immediately following apnea. Resting splenic volume displayed high test-retest reliability between tests (Pilström: 157 ± 39 mL vs 156 ± 34 mL, p = .651, ICC = .970, p < .001, CV = 2.98 ± 0.1%; Prolate ellipsoid: 154 ± 37 mL vs 144 ± 43 mL, p = .122, ICC = .942, p < .001, CV = 5.47 ± 0.3%; Koga: 142 ± 37 mL vs 140 ± 59 mL, p = .845, ICC = .859, p < .001, CV = 9.72 ± 1.4%). Apnea-induced volumes displayed similar reliability (127 ± 29 mL vs 129 ± 28 mL, p = .359, ICC = .967, p < .001, CV = 3.14 ± 3.1%). Reliability was also high between equations (Pilström vs Prolate ellipsoid: ICC = .818, p < .001, CV = 7.33 ± 0.3%, bias = - 3.1 mL, LoA = - 46.9 to 40.7 mL; Pilström vs Koga: ICC = .618, p < .01, CV = 11.83 ± 1.1%, bias = - 14.8 mL, LoA = - 76.9 to 47.3 mL). We conclude that splenic ultrasonographic measurements have practical applications during laboratory and field-based research as a reliable method detecting splenic volume change consistently between repeated tests. The Pilström equation displayed similar reliability compared to the prolate ellipsoid formula and slightly higher compared to the Koga formula and may be particularly useful to account for individual differences in splenic dimensions.

Spleen Contraction During Sudden Eupneic Hypoxia Elevates Hemoglobin Concentration.

The spleen contracts progressively during moderate normobaric hypoxia exposure of 20 min, which elevates hemoglobin concentration (Hb). However, acute hypoxia exposure could be shorter and more severe when oxygen systems fail during, e.g., high-altitude sky diving, aircraft cabin pressure drop, balloon flights, extreme altitude climbing, and in some maladies. We aimed to evaluate the speed and magnitude of spleen contraction during short exposure to extreme eupneic hypoxia and its subsequent recovery on oxygen. Eight female and seven male volunteers were exposed to normobaric hypoxia (10% oxygen) for 10 min during sitting rest, followed by 10 min on 100% oxygen. Heart rate (HR), arterial oxygen saturation (SpO2), and mean arterial blood pressure (MAP) were measured continuously. The spleen was measured via ultrasonic imaging every minute for volume calculations, and venous blood samples were drawn before and after exposure for hemoglobin concentration (Hb). Mean (SD) spleen volume was 279 (115) mL before exposure, 219 (75) mL (21% reduction; P = 0.005) at 3 min of exposure, and 201 (93) mL after 10 min exposure to hypoxia (28% reduction; P < 0.001). Hb was 138.8 (7.6) g·L-1 before and 142.9 (8.1) g·L-1 after 10 min of exposure (2.9% increase; P < 0.001). SpO2 was 96.4 (1.7)% before exposure and 74.7 (8.4)% during the last minute of exposure (22.5% reduction; P < 0.001). HR increased from 80 (14) to 90 (17) bpm during exposure (12% increase, P < 0.05). MAP remained unchanged. After 10 min recovery on oxygen, values had been restored for spleen volume and Hb, while SpO2 was higher and HR lower compared with before hypoxia exposure. We concluded that acute normobaric hypoxia of only 10 min caused significant spleen volume contraction with Hb increase. This rapid spleen response, evident already after 3 min of exposure, could have a protective effect during sudden exposure to severe hypoxia.

Association Between Arterial Oxygen Saturation and Lung Ultrasound B-Lines After Competitive Deep Breath-Hold Diving.

Breath-hold diving (freediving) is an underwater sport that is associated with elevated hydrostatic pressure, which has a compressive effect on the lungs that can lead to the development of pulmonary edema. Pulmonary edema reduces oxygen uptake and thereby the recovery from the hypoxia developed during freediving, and increases the risk of hypoxic syncope. We aimed to examine the efficacy of SpO2, via pulse-oximetry, as a tool to detect pulmonary edema by comparing it to lung ultrasound B-line measurements after deep diving. SpO2 and B-lines were collected in 40 freedivers participating in an international deep freediving competition. SpO2 was measured within 17 ± 6 min and lung B-lines using ultrasound within 44 ± 15 min after surfacing. A specific symptoms questionnaire was used during SpO2 measurements. We found a negative correlation between B-line score and minimum SpO2 (r s = -0.491; p = 0.002) and mean SpO2 (r s = -0.335; p = 0.046). B-line scores were positively correlated with depth (r s = 0.408; p = 0.013), confirming that extra-vascular lung water is increased with deeper dives. Compared to dives that were asymptomatic, symptomatic dives had a 27% greater B-line score, and both a lower mean and minimum SpO2 (all p < 0.05). Indeed, a minimum SpO2 ≤ 95% after a deep dive has a positive predictive value of 29% and a negative predictive value of 100% regarding symptoms. We concluded that elevated B-line scores are associated with reduced SpO2 after dives, suggesting that SpO2 via pulse oximetry could be a useful screening tool to detect increased extra-vascular lung water. The practical application is not to diagnose pulmonary edema based on SpO2 - as pulse oximetry is inexact - rather, to utilize it as a tool to determine which divers require further evaluation before returning to deep freediving.

Application of a Diagnostic Methodology of Cardiac Systems Based on the Proportions of Entropy in Normal Patients and with Different Pathologies.

INTRODUCTION: Dynamical systems theory, probability, and entropy were the substrate for the development of the diagnostic and predictive methodology of adult heart dynamics. OBJECTIVE: To apply a previously developed methodology from dynamical systems, probability, and entropy in both normal and pathological subjects. METHODS: Electrocardiographic records were selected from 30 healthy subjects and 200 with different pathologies, with a length of least 18 h. Numerical attractors from dynamical attractors and the probability of occurrence of ordered pairs of consecutive heart rates were built. A calculation of entropy and its proportions was performed and statistical analysis was conducted. RESULTS: The normal patients' heart dynamics were evaluated according to the methodology of entropy proportions, highlighting that there are differences in normal patients with different pathologies. There was maximal level of sensitivity, specificity, and diagnostic agreement. CONCLUSION: Proportional entropy constitutes a diagnostic and predictive method of heart systems, and may be useful as a tool to objectively diagnose and perform the follow-up of normal and pathological cases.

When the human brain goes diving: using near-infrared spectroscopy to measure cerebral and systemic cardiovascular responses to deep, breath-hold diving in elite freedivers.

Continuous measurements of haemodynamic and oxygenation changes in free living animals remain elusive. However, developments in biomedical technologies may help to fill this knowledge gap. One such technology is continuous-wave near-infrared spectroscopy (CW-NIRS)-a wearable and non-invasive optical technology. Here, we develop a marinized CW-NIRS system and deploy it on elite competition freedivers to test its capacity to function during deep freediving to 107 m depth. We use the oxyhaemoglobin and deoxyhaemoglobin concentration changes measured with CW-NIRS to monitor cerebral haemodynamic changes and oxygenation, arterial saturation and heart rate. Furthermore, using concentration changes in oxyhaemoglobin engendered by cardiac pulsation, we demonstrate the ability to conduct additional feature exploration of cardiac-dependent haemodynamic changes. Freedivers showed cerebral haemodynamic changes characteristic of apnoeic diving, while some divers also showed considerable elevations in venous blood volumes close to the end of diving. Some freedivers also showed pronounced arterial deoxygenation, the most extreme of which resulted in an arterial saturation of 25%. Freedivers also displayed heart rate changes that were comparable to diving mammals both in magnitude and patterns of change. Finally, changes in cardiac waveform associated with heart rates less than 40 bpm were associated with changes indicative of a reduction in vascular compliance. The success here of CW-NIRS to non-invasively measure a suite of physiological phenomenon in a deep-diving mammal highlights its efficacy as a future physiological monitoring tool for human freedivers as well as free living animals. This article is part of the theme issue 'Measuring physiology in free-living animals (Part II)'.

Aplicación de la ley de Zipf-Mandelbrot al diagnóstico de la dinámica cardíaca normal y aguda / Application of the law of Zipf-Mandelbrot to the diagnosis of normal and acute cardiac dynamics

Introducción: Es conocida la capacidad de los fractales estadísticos en la evaluación de la complejidad de diferentes sistemas cuya dinámica pueda ser evaluada a partir de las frecuencias de una variable; para esto, se utiliza la medida de la dimensión fractal estadística, la cual puede ser calculada con la ley de Zipf-Mandelbrot. Esta ley matemática ha sido aplicada en cardiología para evaluar el grado de complejidad de la dinámica cardíaca. En el presente trabajo se aplicó la ley de Zipf-Mandelbrot junto con la metodología diagnóstica desarrollada previamente para evaluar dinámicas cardíacas normales y con enfermedad aguda. Materiales y métodos: Se tomaron 15 registros Holter; 10 con diagnóstico normal y 5 con patologías agudas de pacientes de la Unidad de Cuidados Intensivos. Se organizaron jerárquicamente las frecuencias de aparición de las frecuencias cardíacas de cada dinámica en rangos de a 15 lat/min, en busca del comportamiento hiperbólico necesario para la aplicación de la ley de Zipf-Mandelbrot. Posteriormente se realizó una linealización y se obtuvo la dimensión fractal estadística para cada dinámica. Resultados: Los valores de la dimensión fractal estadística para una dinámica cardíaca aguda variaron entre 0.4925 y 0.6061, mientras que para una dinámica normal variaron entre 0.7134 y 0.9749, evidenciando la diferenciación entre ambos grupos. Conclusiones: El comportamiento fractal estadístico de la dinámica cardíaca fue corroborado, de igual forma la pérdida de complejidad para las dinámicas agudas respecto a las dinámicas normales

Background: The capacity of statistical fractals in the evaluation of the complexity of different systems whose dynamics can be evaluated from the frequencies of a variable is known. This is why the measure of the statistical fractal dimension is used, which can be calculated with the Zipf-Mandelbrot law, this mathematical law has been applied in cardiology evaluating the degree of complexity of cardiac dynamics. In the present work, the Zipf-Mandelbrot law was applied together with the diagnostic methodology previously developed to evaluate normal cardiac dynamics and acute disease. Material and methods: 15 Holter records were taken; 10 with normal diagnosis and 5 with acute pathologies of patients of the Intensive Care Unit. The frequencies of occurrence of the heart frequencies of each dynamics were organized hierarchically in ranges of 15 lat/min, in search of the hyperbolic behavior required for the application of the law of Zipf-Mandelbrot. Subsequently, a linearization was performed and the statistical fractal dimension was obtained for each dynamics. Results: The values of the statistical fractal dimension for acute cardiac dynamics varied between 0.4925 and 0.6061, whereas for normal dynamics they varied between 0.7134 and 0.9749, evidencing the differentiation between both groups. Conclusions: The statistical fractal behavior of the cardiac dynamics was corroborated, as well as the loss of complexity for the acute dynamics with respect to the normal dynamics

Sistemas dinámicos aplicados a la dinámica cardiaca en 18 horas mediante una ley matemática exponencial / Dynamical systems applied to cardiac dynamics in 18 hours by an exponential mathematical law

Objetivo: confirmar la capacidad diagnostica de una ley exponencial de ayuda diagnostica, desarrollada para 21 horas con base en la teoría de sistemas dinámicos junto con la geometría fractal, en evaluaciones realizadas en 18 horas, mediante un estudio de concordancia diagnóstica con respecto al Gold estándar. Materiales y métodos:se realizó un estudio de 60 dinámicas cardiacas evaluadas en Holter y registros electrocardiográficos continuos, de los cuales 15 provienen de sujetos normales y 45 de pacientes con diferentes tipos de patologías cardiacas. Se desarrollaron simulaciones teóricas de la secuencia de las frecuencias cardiacas durante 18 horas, y se construyeron atractores. Se calculó la dimensión fractal de cada atractor y su ocupación espacial en el espacio generalizado de Box-Counting. Se determinó el diagnóstico matemático a partir de la ley y se calculó sensibilidad, especificidad y coeficiente Kappa. Resultados: se encontraron valores para normalidad entre 219 y 373 en la rejilla Kp y entre 49 y 70 para enfermedad aguda, evidenciando que el método permite diferenciar normalidad de enfermedad aguda mediante la ocupación espacial de los atractores valorados desde la ley matemática en 18 horas. Se encontraron valores de sensibilidad y especificidad del 100% y un coeficiente Kappa de 1 al comparar el diagnóstico físico-matemático con el Gold estándar. Conclusión: la ley exponencial de los sistemas dinámicos cardiacos aplicada en 18 horas es útil como herramientade ayuda diagnóstica, permitiendo cuantificar casos normales, en evolución hacia la enfermedad y en estados agudos...(AU)

Objective: to confirm the diagnostic capacity of an exponential diagnostic aid law, developed for 21 hours, based on the theory of dynamic systems along with the fractal geometry, in evaluations carried out in 18 hours, through a diagnostic concordance study with respect to the gold standard. Materials and methods: a study of 60 cardiac dynamics evaluated in Holter and continuous electrocardiographic recordings was performed, of which 15 come from normal subjects and 45 from patients with different types of heart diseases. Theoretical simulations of the sequence of heart rates were developed for 18 hours, and were built attractors. The fractal dimension of each attractor and its spatial occupation in the generalized Box-Counting space was calculated.Mathematical diagnosis is determined from the law and sensitivity, specificity and Kappa coefficient was calculated. Results: values normally found between 219 and 373 in the Kp grid and between 49 and 70 for acute disease, showing that the method can differentiate normal acute disease by spatial occupation of attractors assessed from the mathematical law in 18 hours. Sensitivity and specificity of 100% and a Kappa coefficient of 1 were found by comparing the physical-mathematical diagnosis with the Gold standard. Conclusion: the exponential mathematical law of cardiac dynamic systems applied in 18 hours is useful as a diagnostic aid tool, allowing quantifying normal cases, evolving towards disease and acute conditions...(AU)

Concordancia de lectura de test de ejercicio cardiopulmonar integrado utilizando un protocolo estándar en una población con antecedente de trauma de guerra / Concordance of integrated cardiopulmonary exercise testing interpretations using a standard protocol in a population with a background of war trauma

El test de ejercicio cardiopulmonar evalúa la tolerancia al ejercicio y provee una evaluación integral del sistema respiratorio, cardiovascular y muscular siendo útil en el diagnóstico diferencial de alteraciones cardiopulmonares específicas con desórdenes psicológicos o simulaciones, sin embargo, pueden existir diferencias en su interp Objetivo: evaluar el grado de concordancia interobservador para la interpretación del test de ejercicio cardiopulmonar utilizando el algoritmo diagnóstico de K. Wasserman en una población de pacientes jóvenes con heridas en combate. Materiales y métodos: estudio de concordancia en la interpretación de 33 test de ejercicio cardiopulmonar por tres observadores y dos porgramas computalizados. El análisis se realizó primero entre los resultados de cada una de las observaciones con el diagnóstico final dado por consenso de los observadores y luego se realizó un análisis interobservador con los diferentes diagnósticos a los cual se puede llegar mediante el test utilizando el coeficiente kappa, considerándose estadísticamente significativo una p<0,05. Resultados: las mejores concordancia entre observadores y el diagnóstico final fueron observadas bajo las categorías de normal y anormal, kappa con fuerza de concordancia de débil a buena (0,2725 - 06959 con p<0,05). Cuando los diagnósticos son más específicos los valores kappa disminuyeron. La mejor concordancia entre los observadores se encontró cuando se comparan entre diagnósticos específicos, con coeficientes kappa mas altos para el diagnostico de enfermedades pulmonares. Conclusión: el algoritmo diagnóstico utilizado para la interpretación de los test de ejercicio cardiopulmonar tiene bajos coeficientes de concordancia en general en esta población requiriendo para la misma un adecuado enfoque con historia clínica con algoritmos diagnósticos validados que pueden ser complementados con programas de computador específicos.

Consumo de oxígeno en militares amputados y sujetos sanos previo al ascenso a gran altitud / Oxygen consumption in military amputees and subjects healthy previous to ascent to high altitude

Resumen: el consumo de oxígeno (VO2) varía con la utilización de prótesis y con la altitud donde se obtiene, por lo que comparamos los resultados en cuanto al VO2 de un grupo de sujetos amputados y sanos obtenidos a la altura de Bogotá. Objetivo: comparar los valores VO2 en sujetos con amputación transtibial y en pacientes sanos obtenidos a una altura de 2.690 msnm previo al ascenso a gran altitud. Material y método: comparación de los valores de consumo de oxígeno pico y ajustado por kilogramo de sujetos con entrenamiento físico regular que desarrollaron ascensos exitosos a 5.400 msnm incluidos en series de casos donde se aplicó un test de ejercicio incremental a la altura de Bogotá. Los valores obtenidos fueron comparados a través de Mann Whitney Test. Resultados: se obtuvo información de dos series con un total de 13 personas, la primera de 3 sujetos con amputación transtibial y la otra con 10 sujetos sanos. Todos los amputados eran hombres entre los 27 y 48 años, en el grupo de sujetos sanos se encontraban 8 hombres y 2 mujeres entre los 18 y 46 años. El VO2 pico en amputados fue en promedio de 2.519 L/min con un rango de 2.147 ml/min a 2739 ml/min y en sujetos sanos un promedio de 3.084 con un rango de 2.056 a 4.700 ml/min. El VO2/kg en amputados fue en promedio de 34 con un rango de 26 a 40 ml/kg/min y en sanos de 45,9 con un rango de 31 a 68. La comparación por grupos independientes no mostró diferencia en el consumo pico pero si cuando se ajusta por kg. Conclusión: no hay diferencias entre los valores obtenidos a nivel de Bogotá en cuanto a VO2 pico entre sujetos sanos y amputados, sin embargo, cuando se ajusta por kilogramo, los amputados muestran un consumo menor con diferencia significativa.

Edema pulmonar inducido por las alturas / High altitude pulmonary edema

El edema pulmonar inducido por las alturas hace parte del grupo de enfermedades inducidas por la altitud. En la actualidad existen numerosas inquietudes en su fisiopatología, manifestaciones clínicas y tratamiento. En el presente artículo se revisa la literatura disponible hasta el momento de esta enfermedad, pretendiendo aclarar estos aspectos. Además, se hace referencia a los resultados de estudios realizados en Colombia, con el fin de orientar un manejo adecuado de estos pacientes en nuestro medio.

Correlacion entre los niveles de citoquinas en el lavado broncoalveolar en una cohorte de pacientes del Hospital Militar Central con esclerosis sistemica (SS), con y sin alveolitis / Cytokines in bronchoalveolar lavage in systemic sclerosis patient

Debido a la preocupación que produce la osteomielitis crónica y los problemas sociales y laborales que conlleva esta enfermedad, nos propusimos sacar adelante un protocolo de tratamiento médico-ortopédico que hemos implementando y desarrollado con la colaboración del Dr. Cesar Arango (Medico Infectólogo) en nuestros pacientes durante 20 años. Hemos utilizado esta metodología en 180 pacientes, 100 de sexo masculino y 80 de sexo femenino. Los segmentos anatómicos afectados fueron: tibia 56 por ciento, fémur 33 por ciento, antebrazo 6 por ciento, pie 4 por ciento y dedos de pie 1 por ciento. La base fundamental del tratamiento es el desbridamiento seriado de las lesiones con el paciente hospitalizado, la toma de cuatro cultivos en la primera intervención, la administración de antibióticos se lleva a cabo de acuerdo a determinación del medico infectólogo que se modifica según el resultado de los cultivos, y el cuidado postoperatorio domiciliario hasta obtener una granulación adecuada de las zonas desbridadas con cultivos negativos. Se rellena el espacio vado producido por los desbridamientos con injertos óseos extraídos de las espinas ilíacas provista la estabilización de la fractura. De estos 180 pacientes, el 97 por ciento se encuentra hasta el momento libre de recidivas, 5 pacientes no cumplieron con las expectativas del tratamiento y 1 paciente fue amputado. Consideramos que esta forma de tratamiento es adecuada para nuestro medio y mejora el pronóstico de los pacientes que sufren esta penosa enfermedad