[Predictors factors for the extubation failure in two or more times among preterm newborn]. / Factores predictores para falla en la extubación en dos o más ocasiones en el recién nacido de pretérmino.

INTRODUCTION: With the ventilatory mechanical attendance has been prolonged the life of the preterm newborn (PTNB) critically sick and during that lapse many occasions it is necessary reintubation to PTNB in two or more times with the subsequent damage that makes enter to the patient to a vicious circle with more damage during the same reintubated. The objective of this study was to determine the factors that predict the extubation failure among PTNB from 28 to 36 weeks of gestational age in two or more times. MATERIAL AND METHODS: It was considered extubation failure when in the first 72 hours of being had extubated the patient; there was reintubation necessity, independent of the cause that originated it. For the second extubation or more took the same approach. During the period of September to December of the 2004 were included in retrospective study to all PTNB that were interned in one hospital of third level that fulfilled the inclusion approaches (one study published where we take account the first extubation failure) and in retrolective study to the patients of the same hospital of January to October of the 2006. They were formed two groups, group A of cases (who failed in extubation two or more times) and the B of controls (who failed in extubation for the first time). The descriptive statistic and the inferential through of Student t test or Mann-Whitney U or rank sum test Wilcoxon, in suitable case; Chi-square or Fisher's exact test was used. Odds ratio (OR) and multivariate analysis for to study predictors factors for the extubation failure was employed. Statistical significance was considered at p < 0.05. RESULTS: The group A it was conformed by 21 patients and the group B for 20 patients. In the multivariate analysis it was association like predictive factor for fail of the second extubation to the presence of postextubation atelectasis with an OR 19.2 with IC to 95% of 3.1-117 (P = 0.001) and preextubation oxygenation index (IO2) >2, OR 5.3, IC to 95% of 1.3-21.4 (P = 0.02). In the bronchoscopy study they were some anatomical alterations that they explained the extubation failure in the second time. CONCLUSIONS: We conclude that it is important to plan an extubation in the PTNB, when there has already been a previous failure, and to avoid the well-known predictors factors for extubation failure as much as possible in the extubation in the PTNB, and that according to that found in this study non to extubate with an IO2 >2, and to manage the atelectasis postextubation intensively. Later to the pursuit of those limits and after a second extubation failure, be probably necessary to pass to bronchoscopy if the patient's conditions allow it.

[Risk factors associated to complications of the mechanical ventilatory assistance in the premature newborn]. / Factores de riesgo asociados a complicaciones de la asistencia mecánica ventilatoria en el recién nacido prematuro.

OBJECTIVE: To determine risk factors associated with the presence of complications with mechanical ventilatory support (MVS) in the preterm infants (PI). METHODS: One hundred thirty medical records of PI that had been discharged by amelioration or death were reviewed retrospectively. They were divided in two groups: group A, PI that had presented complications during MVS (cases) and B, PI with MVS, but that had not presented complications due to the procedure (controls). Statistical significance was considered at p < 0.05. RESULTS: The significative risk factors in the multivariate analysis reached significance for the associated of complications: gestational age (32 weeks or less), orotracheal reintubations three o more times, cycles of 60 per minute or more at the third day of being had initiate the MVS, and the symptomatic patent ductus arteriosus (PDA), all with p < 0.05. CONCLUSIONS: It will be necessary to impact more on the cycles level to diminish him below 60 per minute to the third day when it is feasible, to make the smallest reintubations number, to correct quickly the PDA when it is symptomatic, to avoid this way as much as possible, the complications of the MVS.

[Predictor factors for the production of bronchopulmonary dysplasia in the preterm newborn]. / Factores predictores para la producción de displasia broncopulmonar en el recién nacido de pretérmino.

INTRODUCTION: The bronchopulmonary dysplasia (BPD) is a lung illness chronicle that is developed in preterm newborn (PTNB) mainly, secondary to multiple factors of risk which have not been studied completely. OBJECTIVE: To determine the predictors factors (of risk factors) for the production of BPD in the PTNB of 28 at 36 weeks of gestational age. MATERIAL AND METHODS: Eighty medical records from January 2004 to May 2006 of PTNB that there was received mechanical attendance to the ventilation (MAV) at least 24 hrs were reviewed retrospectively. They were divided in two groups: group A, PTNB that had BPD, composed of 40 patients (cases) and group B, PTNB with MAV but that had not developed BPD due to the procedure of 40 patients too (controls). It was used descriptive and inferential statistic. Odds ratio (OR) and multivariate analysis were used to study predictors factors. Statistical significance was considered with P < 0.05. RESULTS: There was significant difference of the supply of the intravenous (i.v.) fluids the days 2, 3, 4 and 7 of extrauterine life (EUL), of the oxygen inspired fraction (FiO2) of in the day 7 of being had initiate the MAV, of the peak inspiratory pressure (PIP) in the day 1 and 3 of being had initiate the MAV everything to favor of the cases, with P < 0.05. In the multivariate analysis was significative in the intake of i.v. fluids > or = 140 mL x kg of weight x day to the fourth day of EUL, the oxygen arterial pressure (PaO2) > 70 mm Hg for > 4 days, reintubations number (two or more times) and the symptomatic patent ductus arteriosus (PDA), all with P < 0.05. CONCLUSIONS: We concluded that, in critically sick PTNB, they exist one series of well-known risk factors but more specified in this study that they should avoid as much as possible; the handling of the liquids i.v. should be cautious, not to spend of 139 mL x kg x day to the 4th day of EUL, not to be so permissive with the PaO2 maintaining it in values < or = 70 mm of Hg after four days, to avoid as much as possible the reintubations and to treat the but quick the symptomatic PDA still without that it is significant, to diminish this way, the risk of BPD.

[Comparison of oxygen saturation among newborns with bronchopulmonary dysplasia during and after feeding]. / Comparación de la saturación de oxígeno en lactantes con displasia broncopulmonar antes, durante y después de la alimentación.

BACKGROUND: Bronchopulmonary dysplasia (BPD) is associated with frequent events of hypoxemia specially during feeding. OBJECTIVE: Determine peripheral oxygen saturation (SpO2) among infants with BPD before, during and after feeding. METHODS: Patients with diagnosis of BPD were prospectively studied between July-September, 2005. SpO2 was measured with a manual digital pulsioxymeter 5 times during feeding. Alpha levels were set at p<0.05. RESULTS: 67 events were studied in 18 patients. For each participant, oxygen saturation was measured five times yielding a total of 335 recordings. Frequent desaturation episodes were recorded during feeding, (SpO2<88%) in 16 of the 18 cases. SpO2 reached 80% for some recordings among 67% of participants (n=12), with p<0.001. CONCLUSION: Among BDP patients, SpO2 decreases during feeding, reaching severe desaturations (SpO2<80%) among in two thirds of the cases. Oxygen concentration must be sufficiently increased during feeding in order to rise the level of SpO2 to a minimum of 88%.

Comparación de la saturación de oxígeno en lactantes con displasia broncopulmonar antes, durante y después de la alimentación / Comparison of oxygen saturation among newborns with bronchopulmonary dysplasia during and after feeding

Antecedentes: La displasia broncopulmonar se relaciona con eventos frecuentes de hipoxemia, en especial durante la alimentación. El objetivo de este estudio fue determinar la saturación periférica de oxígeno (SpO2) en lactantes con displasia broncopulmonar, antes, durante y después de la alimentación. Métodos: Prospectivamente se estudiaron pacientes con displasia broncopulmonar del 1 de julio al 30 de septiembre de 2005, realizando mediciones de SpO2 a través de un pulsioxímetro digital de mano en cinco ocasiones con relación a la alimentación. Se consideró zona de significancia con p<0.05. Resultados: En 18 pacientes se estudiaron 67 eventos, midiendo en cada uno la SpO2 en cinco ocasiones, para un total de 335 mediciones; hubo momentos de desaturación frecuentes (SpO2 menor de 88%) en 16 pacientes de los 18, y SpO2 por debajo de 80% en alguna medición, en 67% de ellos (n=12), con p<0.001. Conclusiones: La SpO2 en pacientes con displasia broncopulmonar disminuye durante la alimentación llegando a niveles severos (menos de 80%) en las dos terceras partes de los casos, por lo que se sugiere que durante la misma se incremente la concentración de oxígeno lo suficiente como para llevarlos a una saturación de 88%, por lo menos.

BACKGROUND: Bronchopulmonary dysplasia (BPD) is associated with frequent events of hypoxemia specially during feeding. OBJECTIVE: Determine peripheral oxygen saturation (SpO2) among infants with BPD before, during and after feeding. METHODS: Patients with diagnosis of BPD were prospectively studied between July-September, 2005. SpO2 was measured with a manual digital pulsioxymeter 5 times during feeding. Alpha levels were set at p<0.05. RESULTS: 67 events were studied in 18 patients. For each participant, oxygen saturation was measured five times yielding a total of 335 recordings. Frequent desaturation episodes were recorded during feeding, (SpO2<88%) in 16 of the 18 cases. SpO2 reached 80% for some recordings among 67% of participants (n=12), with p<0.001. CONCLUSION: Among BDP patients, SpO2 decreases during feeding, reaching severe desaturations (SpO2<80%) among in two thirds of the cases. Oxygen concentration must be sufficiently increased during feeding in order to rise the level of SpO2 to a minimum of 88%.

[Predictive factors of failure extubation among preterm infants]. / Factores predictores de falla en la extubación en recién nacidos de pretérmino.

OBJECTIVE: To determine the factors that lead to extubation failure among preterm newborns (PTN). MATERIAL AND METHODS: Failure was determined when patients had to be reintubated during the first 72 hours. Critically-ill preterm newborns needing mechanical assisted ventilation at least during 24 hours were studied prospectively. Two groups were included: Group A, who failed in extubation for the first time and Group B, a control group who did not fail. Significance was set a p <0.05. RESULTS: Gestational age and birth weight showed significant differences in Group B (control group). Significant factors in the multivariate analysis were gestational age < 32 weeks, caloric intake < or = 100 calories/kg/day and mean airway pressure (MAP) > or = [corrected] 4.5 cm H2O. CONCLUSIONS: According to our results, an extubation should be planned whenever a patient is a PTN, has a gestational age of <32 weeks, a caloric intake >100 cal/kg/day, and its ventilator MAP is <4.5 cm H2O.

Factores predictores de falla en la extubación en recién nacidos de pretérmino / Predictive factors of failure extubation among preterm infants

Objetivo: Determinar los factores que originan la falla en la extubación en recién nacidos de pretérmino (RNPT). Material y métodos: Se consideró falla en la extubación cuando hubo necesidad de reintubar al paciente en las primeras 72 horas. Se estudiaron en forma prospectiva a los RNPT críticamente enfermos que habían estado con asistencia mecánica ventilatoria durante por lo menos 24 horas. Se integraron 2 grupos: un grupo A (casos) con RNPT que tuvieron fallas en la primera extubación y un grupo B (control) con RNPT que no tuvieron fallas en la extubación. Se consideró zona de significancia con p menor a 0.05. Resultados: La edad gestacional y el peso al nacer mostraron diferencias significativas a favor del grupo B (control). Los factores que mostraron significancia en el análisis multivariado, fueron la edad gestacional (< 32 semanas), el aporte calórico (≤ 100 cal/Kg/ día) y la presión media de vías aéreas (PMVA) (≥ 4.5 cm H2O). Conclusiones: De acuerdo con lo encontrado en este estudio, antes de realizar la extubación habrá que considerar si el RNPT tiene menos de 32 semanas de edad gestacional, por lo menos un aporte calórico superior a 100 cal/Kg/día y una PMVA en el ventilador menor a 4.5 cm H2O.

OBJECTIVE: To determine the factors that lead to extubation failure among preterm newborns (PTN). MATERIAL AND METHODS: Failure was determined when patients had to be reintubated during the first 72 hours. Critically-ill preterm newborns needing mechanical assisted ventilation at least during 24 hours were studied prospectively. Two groups were included: Group A, who failed in extubation for the first time and Group B, a control group who did not fail. Significance was set a p <0.05. RESULTS: Gestational age and birth weight showed significant differences in Group B (control group). Significant factors in the multivariate analysis were gestational age < 32 weeks, caloric intake < or = 100 calories/kg/day and mean airway pressure (MAP) > or = [corrected] 4.5 cm H2O. CONCLUSIONS: According to our results, an extubation should be planned whenever a patient is a PTN, has a gestational age of <32 weeks, a caloric intake >100 cal/kg/day, and its ventilator MAP is <4.5 cm H2O.

[Predisposing risk factors that participate in neonatal sepsis mortality rate]. / Posibles factores de riesgo que influyen en la mortalidad por sepsis neonatal.

BACKGROUND: Neonatal sepsis is a frequent diagnosis in neonatal intensive care units and has been associated with a high mortality rate. OBJECTIVE: To determine the possible association between various risk factors and neonatal sepsis mortality rate. DESIGN: Cohort case control. MATERIAL AND METHODS: Two hundred medical records of newborns discharged from a neonatology unit, from January 1998 to June 2002, with a neonatal sepsis diagnosis were reviewed. RESULTS: There was significance in birth weight of 1000 g or less, vein dissection for insertion of central venous catheter, gestational age of 30 weeks or less, and presence of mechanical ventilatory assistance (p < 0.01). Total parenteral nutrition also reached significance but as protective factor (OR: 0.15, CI 95% 0.07 - 0.31) (p < 0.001). The multivariate analysis displayed similar results, except birth weight (p < 0.01). CONCLUSIONS: The above mentioned risk factors should be prevented in as much as possible. A factor to prevent mortality is total parenteral nutrition which should be always employed in cases where this is feasible.

Adaptación psicosocial y psicopatología de niños con enuresis y sus hermanos: Un estudio comparativo / Psychosocial adaptation and psychopathology of children with enuresis and their siblings: A comparative study

Introducción. En los niños con enuresis no debida a enfermedad médica es común la presencia de síntomas psicológicos. El objetivo de este estudio fue explorar si existen diferencias en adaptación psicosocial y grado de psicopatología de niños con enuresis en comparación con sus hermanos sin enuresis. Material y métodos. Estudio transversal, comparativo, observacional y abierto de 30 niños enuréticos de 9 a 14 años de edad, referidos al psiquiatra por sus médicos familiares, y sus hermanos no enuréticos. Ellos y sus progenitores respondieron la Escala de Columbia (CIS) que mide adaptación psicosocial y la Escala de Comportamiento de Niños y Adolescentes (CBCL), que mide grado de psicopatología. Los datos fueron analizados mediante coeficiente de correlación de Spearman y x2. Resultados. El tipo de enuresis más frecuente fue el nocturno (25). Los progenitores empleaban medidas punitivas en su corrección, además de dar a sus hijos infusiones y ungüentos. Más de la mitad de los niños enuréticos y ninguno de sus hermanos sanos presentaron psicopatología en grado clínico. Casi todos los niños enuréticos (29) y sólo 2 de los no enuréticos manifestaron mala adaptación psicosocial. Las diferencias fueron significativas. Conclusiones. Los niños con enuresis mostraron más psicopatología, y sobre todo más mala adaptación psicosocial, que sus hermanos no enuréticos, lo cual puede deberse a comorbilidad asociada o resultar del hecho de mojar la cama. Las medidas correctivas empleadas por los progenitores eran inútiles o francamente punitivas. Es necesario que pediatras y médicos familiares ejerzan acciones psicoeducativas para corregir las ideas distorsionadas que, con fuerte influencia cultural, mantienen los progenitores sobre las causas y el tratamiento de la enuresis.

Introduction. Behavioral disorders in children and adolescents with enuresis not due to general medical conditions are common. The objective of this study was to demonstrate differences in psychosocial adaptation between children with enuresis and their nonenuretic siblings. Material and methods. This was a cross sectional, comparative, observational and open study of 30 children 9 to 14 years of age with enuresis, referred to the psychiatrist by their family physicians, and their healthy siblings. Both groups of children and their parents responded the Columbia Impairment Scale, which assesses functional impairment and the parents responded the Child Behavior Checklist to assess their children's psychopathology. Data were analyzed with Spearman's correlation and x2. Results. Primary enuresis was the most common type (25). Parents used to employ punitive measures in an attempt to correct the symptom, besides ointments and herbal infusions. More than half of children with enuresis and none of their healthy siblings had clinical psychopathology scores in CBCL. Almost all children with enuresis (29) and only 2 of their siblings had functional impairment in CIS. Differences between both groups were significant. Conclusions. Children with enuresis showed more psychopathology and functional impairment than their healthy siblings. This may be due either to associated comorbidity or to bed-wetting itself. Corrective measures practiced by parents were useless or even aggressive. It is necessary for pediatricians and family physicians to give psychoeducation to parents of children with enuresis in order to correct culturally influenced distorted ideas on the causes and treatment of enuresis.

[Risk factors for presence of complications of the mechanical ventilatory assistance in the newborn]. / Factores de riesgo para la presencia de complicaciones de la asistencia mecánica ventilatoria en el recién nacido.

BACKGROUND: The mechanical ventilatory assistance (MVA) is a procedure that is used very often in the neonatal intensive care units but its use its linked to a lot of complications. The objective of this study was to determine the risk factors for the presence of complications of the MVA in the newborns infants. MATERIAL AND METHODS: One hundred thirty five medical records from January 98 to June 2000 of newborns that had been discharged by amelioration or death were reviewed retrospectively. All of them had been received MVA; twenty medical record were excluded. They were divided in two groups: group A, neonates that had presented complications during MVA, composed of 40 patients (cases) and B, neonates with MVA, but that had not presented complications due to the procedure of 75 patients (controls). In group A there were 39 preterm neonates and in B, 58 preterm neonates, the rest were term neonates. It was used descriptive and inferential statistics. Odds ratio (OR) and multivariate analysis were used to study risk factors with confidence interval (CI) of 95%. Statistical significance was considered at p < 0.05. RESULTS: There was significative difference in birth weight. Gestational age and Apgar score between the two groups in favor of group B. There was significative difference too in inspiratory oxygen fraction (IOF), the peak inspiratory pressure (PIP) and cycles in favor of group A (before complications occur). The significative risk factors in the bivariate analysis for the presence complications were: birth weight of 1,500 g or less, 36 weeks of gestational age or less, total time of ventilation of seven days or more , IOF of 1 (100%), cycles of 60 per minute or more and peak inspiratory pressure (PIP) of 30 cm of water or more in the first days of life (all with p < 0.05). The combination of prematurity plus respiratory distress syndrome (RDS) as admission diagnosis reached significance for the presence of complications with an OR of 7.34 and CI of 95% from 1.91 to 23.05, p = 0.001 and the multivariate analysis reached significance for the presence of complications: low birth weight, total time of ventilation of seven days or more, IOF of 1 (100%), cycles of 60 per minute or more, and the combination of prematurity plus RDS as admission diagnosis all with p < 0.05. The mortality was associated significatively to the complications with p < 0.009. The more frequent complications were pneumonia, pulmonary interstitial emphysema and bronchopulmonary dysplasia. CONCLUSIONS: We concluded that newborn patients critically ill, with low birth weight, low gestational age, with RDS, who need more ventilatory support will be more liable to have complications and, as consequence, the mortality will be increased. For this reason it is essential a close monitoring of this group of patients for not over supporting them in IOF, PIP and cycles, thus avoiding as far as possible, the complications of the MVA.

Toll-like receptors: dysregulation in vivo in patients with acute respiratory distress syndrome.

OBJECTIVE: To determine the time course of the expression of five toll-like receptors (TLRs 1-5) in mixed blood mononuclear cells and their relationship to pro-inflammatory and anti-inflammatory cytokines during acute respiratory distress syndrome (ARDS). MATERIAL AND METHODS: In a prospective, a longitudinal study was done at an intensive-care unit of a university-affiliated hospital. Seven consecutive patients with ARDS were studied. We followed the onset and progression of ARDS, and subsequent patient recovery or death, and compared patient data with data from a group of healthy volunteers. We separated mixed blood mononuclear cells using Ficoll-Hypaque to detect the transcripts of human TLRs 1-5. TLR mRNAs were isolated by semiquantitative reverse-transcription PCR (RT-PCR). Each signal was expressed as the ratio of TLR mRNA to beta-actin. Cytokines, including tumor necrosis factor alpha, interferon gamma, and interleukins 4, 6, 8, 10, and 12, were assayed using commercial ELISA kits. RESULTS: Dysregulation in the transcription of TLRs gene, principally in ARDS surviving patients, was observed. Down-regulated expressions of TLR1, TLR4, and TLR5 mRNAs were observed in the first 24 h in patients who survived, and probably played a key role in the survival of patients with ARDS caused by sepsis. Serum levels of cytokines such as IL-6, 8 and 10 were significantly increased in patients with ARDS as compared with levels in the healthy volunteers. However, serum levels of IL-12 were lower in patients with ARDS than in the healthy volunteers. There was difference in serum cytokines concentration between survivors and non-survivors patients with ARDS (except for interleukin-10). CONCLUSIONS: Thus, TLRs gene dysregulation and cytokine profiles are probably important prognostic factors for patient outcome and survival after ARDS.

[The epidemiology of Cancer among adolescents]. / Epidemiología del cáncer en adolescentes.

OBJECTIVE: To review the international literature on adolescent cancer epidemiology. MATERIAL AND METHODS: The Medline database was searched to obtain all papers on adolescent cancer epidemiology published during a period of 15 years (1985-1999). Time, place, and person variables were analyzed, as well as their relationships. RESULTS: Few papers on adolescent cancer epidemiology were found, likely due to the difficulty in registering cancer cases in the 12 to 18 year-old group. Either the 10-14 or the 15-19 year-old group has been analyzed in different studies; but the latter is more representative of teenagers. A higher incidence rate was found in this group (117.3 and 202.2 x 10(6) respectively). The main malignancies in the 15-19 year-old group were central nervous system tumors (CNST), leukemias, lymphomas, bone tumors, germ-cell tumors, and carcinomas. Incidence rates were higher in males and whites; an increasing trend was observed. Cancer mortality in this group is decreasing in the United States (2.0 or 3.2% per year). Survival is increasing in all groups of neoplasms. No data were available on cancer incidence in the 15-19 year-old group in Mexico: data were available only for the 10-14 year-old group. The main neoplasms are leukemias, lymphomas, bone tumors, and CNST (rates were 41.9, 29.9, 12.0, and 10.0 x 10(6), respectively). The mortality rate for the 1990-1994 period was 64.1 and the main neoplasms were leukemias, CNST, and lymphomas. CONCLUSIONS: More studies are needed to address the descriptive epidemiology of cancer in teenagers.

Epidemiología del cáncer en adolescentes / The epidemiology of cancer in adolescents

OBJETIVO: Revisar los artículos publicados sobre la epidemiología del cáncer en adolescentes en el ámbito mundial. MATERIAL Y MÉTODOS: Se revisó la literatura médica (Medline) nacional e internacional para un periodo de 15 años (1985-1999). Se calcularon frecuencias. RESULTADOS: En general se conoce poco de la epidemiología del cáncer en adolescentes porque es difícil el registro de los casos que se presentan en el grupo de 12 a 18 años. Como adolescentes se ha tomado al grupo de 10 a 14 o el de 15 a 19 años de edad, en donde este último incluye mejor los casos que se presentan en esta edad. La incidencia es mayor para el segundo grupo (117.3 y 202.2 [tasas x 10(6)] respectivamente). Las principales neoplasias para el grupo de 15 a 19 años de edad fueron los tumores del sistema nervioso central (TSNC), las leucemias, los linfomas, los tumores óseos, los de células germinales y carcinomas. La incidencia es mayor en el sexo masculino y la raza blanca. Existe una tendencia al incremento. La mortalidad en adolescentes ha disminuido (2.0 a 3.2 por ciento por año en Estados Unidos de América [EUA]). La sobrevida se ha incrementado en todos los tipos de neoplasias. En México no se cuenta con datos de incidencia para el grupo de 15 a 19 años de edad; sólo se tiene para el de 10 a 14 años; las principales neoplasias son leucemias, linfomas, tumores óseos y los TSNC, con tasas por 10(6) de 41.9, 29.9, 12.0 y 10.0 respectivamente. La tasa de mortalidad por cáncer para el periodo de 1990 a 1994 fue de 64.1, y las principales causas de muerte fueron las leucemias, los TSNC y los linfomas. CONCLUSIONES: Es recomendable, en general, y en particular, en nuestro país, el desarrollo de proyectos dirigidos a conocer y difundir la epidemiología descriptiva del cáncer en adolescentes

Edad pulmonar por espirometría y su correlación con la edad cronológica de pacientes con asma / Pulmonary age by spirometric and its correlation with the chronological age of patients with asthma

Antecedentes: la edad pulmonar, como índice espirométrico de regresión lineal, expresa la función ventilatoria pulmonar. Objetivo: conocer las diferencias en los valores del índice de edad pulmonar y edad cronológica en pacientes con asma y voluntarios sanos. Material y método: se estudió a 111 sujetos, 31 sanos y 80 con asma, a todos se les hizo espirometría. Resultados: los sanos tuvieron una edad cronológica promedio de 35 años, con edad pulmonar de 26 años. Los asmáticos, una edad promedio de 38 años, con edad pulmonar de 59 años. Conclusión: el tiempo de evolución de la enfermedad y la severidad del asma incrementan la edad pulmonar.

Características del estudiante de medicina asociadas al éxito ulterior como médico / Characteristic of the medical student associated to posterior success as a physician

Objetivo. Identificar los factores presentes en el estudiante médico durante la carrera que se asocian a alcanzar el éxito en la práctica de la medicina. Diseño. Casos y controles prolectivo de casos prevalentes. Sitio del estudio. Area metropolitana de la ciudad de México. Unidades de estudio. Se estudiaron 120 médicos considerados como de éxito y 245 médicos que no alcanzaron los criterios establecidos en esta investigación para considerarlo un médico exitoso. Mediciones principales. Se construyó un índice de éxito a partir de la opinión de 134 médicos de las diferentes instituciones de salud, tanto públicas como privadas, compuesto de nueve criterios que incluyeron la incorporación a asociaciones académicas de prestigio, la práctica de actividades de atención médica en instituciones públicas y privadas de tercer nivel de atención, la realización de estudios de posgrado, desempeño como docente e investigador, funciones en puestos directivos, e ingresos económicos altos. Resultados. Los principales factores asociados al éxito fueron el antecedente de realización de actividades culturales en forma frecuente por la familia de la cual provenía el entrevistado (RM = 5.2, IC 95 por ciento = 3.15 - 8.60, p = 0.00000001), el promedio mayor a 8.5 durante la carrera (RM = 4.43, IC 95 por ciento = 2.64 - 7.49, p = 0.00000001) y la obtención de premios, becas o distinciones durante los estudios (RM = 4.3, IC 95 por ciento = 2.64 - 7.03, p = 0.00000001). Un modelo de regresión logística seleccionó el antecedente de actividades culturales en la familia, el promedio obtenido durante la carrera, y la obtención de premios, becas o distinciones, como las variables asociadas en forma independiente al éxito (p = 0.00001). Conclusiones. Los antecedentes de actividades culturales familiares del estudiante de medicina y sus antecedentes académicos, fueron los factores durante la carrera de medicina que se asociaron al éxito en su ejercicio profesional ulterior

El tamaño de muestra: un enfoque práctico en la investigación clínica pediátrica / Sample size: a practical viewpoint in pediatric clinical research

El obejtivo del presente artículo es proporcionar al médico las bases conceptuales y prácticas que le permitan calcular el tamaño de muestra en estudios clínicos. Se presentan las definiciones de los diferentes diseños clínicos, incidencia, prevalencia, error tipo I y II, riesgo relativo y razón de momios. Se desarrolla la respuesta a 4 preguntas: 1) ¿Cuando es necesario calcular un tamaño de muestra?, 2) ¿Qué significa la representatividad de una muestra?. 3) ¿Cuál es el tamaño de muestra mínimo que se necesita para probar una determinada hipótesis?, y 4) ¿Cómo saber si el tamaño de muestra que ya se obtuvo era suficiente para el propósito del estudio? Se presentan también las fórmulas para el cálculo del tamaño de la muestra para los ensayos clínicos aleatorizados, estudios de cohortes, casos y controles y transversales. Finalmente se muestra la utilidad de calcular el poder de la muestra cuando se ha terminado un estudio y no se encontró una asociación estadísticamente significativa

Eficacia diagnóstica del método de Capurro "A" y del método radiológico de longitud de columna en la valoración de la edad gestacional / Diagnostic validity between Capurro \"A\" method and the thoracic spinal column weight-height radiological method in the measurement of gestational age

Objetivos. 1) Identificar el grado de validez diagnóstica del método de Capurro "A" y del método radiológico de columna torácica-peso-talla para la medición de la edad gestacional y, 2) Determinar el nivel de corte ideal de anormalidad para ambos métodos en el diagnóstico de niños de pretermino y postmaduros. Diseño de la investigación. Encuesta comparativa. Sitio del estudio. Hospital de Gineco-obstetricia se segundo nivel de atención médica del Instituto Nacional Mexicano del Seguro Social. Unidades de estudio. Se evaluaron 305 recién nacidos, con edades comprendidas entre 29 y 42.4 semanas gestacionales estimadas por el método de Dubowitz. Mediciones principales. A todos los pacientes se les midieron dos índices clínicos para valorar la edad gestacional (métodos de Capurro "A" y de Dubowitz; este último fue considerado como el estándar de oro) y se les practicó una radiografía anteroposterior de tórax. Resultados. El rendimiento diagnóstico del método de Capurro "A" fue superior al método radiológico en la identificación de los niños de pretermino en forma global y específicamente para los niños de pretermino hipotróficos. Cuando se analizaron los niños de término, el método de Capurro fue consistentemente superior tanto para la identificación de los niños de término en general, como de los niños de término hipotróficos e hipertróficos. En este último caso, así como en el de los niños postmaduros ambos métodos mostraron ser ineficaces como métodos de diagnóstico. El punto de corte ideal identificado por medio de curvas ROC, establecido para separar a los niños de término de los de pretermino, varió entre 37 y 38 semanas de acuerdo al método diagnóstio y a la edad gestacional evaluada. Conclusiones. El método de Capurro "A" permite establecer correctamente el diagnóstico diferencial entre los niños de término y de pretérmino. No es un método útil para identificar entre niños de término y los niños postmaduros. Este método demostró ser superior al método radiológico de columna para la determinación de la edad gestacional

Frecuencia de satisfacción con la atención médica en familiares de pacientes pediátricos hospitalizados / Frequency of satisfaction among relatives with medical care of hospitalized pediatric patients

Objetivos. 1. Identificar la frecuencia de satisfacción global con la atención médica en familiares de pacientes pediátricos hospitalizados, 2. Identificar la frecuencia de satisfacción con cada uno de los grupos de personal que participan en la atención de los pacientes y 3. Identificar los aspectos específicos de la atención en los que se presenta la mayor frecuencia de satisfacción e insatisfacción. Diseño de la investigación. Se realizó una encuesta comparativa prolectiva en un hospital pediátrico de tercer nivel de atención que incluyó a 600 familiares. Mediciones principales. Se utilizó un cuestionario autoaplicable, con 51 preguntas con formato de respuestas cerradas, el cual exploraba la satisfacción de los familiares respecto a los médicos tratantes, a los auxiliares clínicos, personal de trabajo social, servicio de foráneos y personal de apoyo. La satisfacción global se identificó de dos formas. En la primera se preguntó a los familiares directamente acerca de su satisfacción y en la segunda, se construyó un índice en el cual se consideró como satisfacción, cuando el paciente manifestaba su conformidad con más del 75 por ciento de los aspectos evaluados. Resultados. La frecuencia de satisfacción global manifestada explícitamente por el familiar ocurrió en el 99 por ciento de los casos (IC 95 por ciento = 98.7 por ciento - 99.99 por ciento, n=589). De manera similar, la frecuencia de familiares satisfechos globalmente de acuerdo al índice fue de 92 por ciento (IC 95 por ciento = 90.1 por ciento - 94.4 por ciento n=553). La frecuencia de satisfacción de los familiares con el grupo médico ocurrió en 87 por ciento de los casos, con el personal de apoyo en 84 por ciento con el servicio de foráneos en 81 por ciento, con los auxiliares clínicos en 79 por ciento y con el personal de trabajo social en 67 por ciento (P=0.00000001). Los aspectos específicos de la atención en los que se identificó una mayor frecuencia de insatisfacción fueron: la no explicación de los procedimientos por parte del personal de laboratorio (41 por ciento), el no conocer a la dietista (37 por ciento). Conclusiones. La frecuencia de satisfacción global por parte de los familiares de pacientes pediátricos hospitalizados fue alta. El personal médico fue el grupo hacia el que se expresó una mayor frecuencia de satisfacción. Los aspectos específicos de la atención relacionados con los auxiliares clínicos, fueron en los que se identificó la mayor frecuencia de insatisfacción por parte de los familiares de los pacientes

Tau b de Kendall para datos agrupados: señalamiento de discrepancia / Kendall's tau b coefficient of correlation. Description of a discrepancy

Las técnicas estadísticas no paramétricas han tenido una creciente aplicación en las últimas dos décadas en el campo de la investigación clínica. El empleo de estos métodos debe estar sujeto a una revisión permanente de la descripción original de los mismos, debido a la posibilidad de que se generen errores que pudieran ser difundidos en forma amplia y por largo tiempo. En este trabajo se describe una discerepancia en las fórmulas comúnmente utilizadas para calcular el coeficiente de correlación tau b de kendall para datos agrupados y se revisa su posible repercusión sobre los resultados e interpretación de los datos