Early rise in central venous pressure during a spontaneous breathing trial: A promising test to identify patients at high risk of weaning failure?

BACKGROUND: The spontaneous breathing trial (SBT) assesses the risk of weaning failure by evaluating some physiological responses to the massive venous return increase imposed by discontinuing positive pressure ventilation. This trial can be very demanding for some critically ill patients, inducing excessive physical and cardiovascular stress, including muscle fatigue, heart ischemia and eventually cardiac dysfunction. Extubation failure with emergency reintubation is a serious adverse consequence of a failed weaning process. Some data suggest that as many as 50% of patients that fail weaning do so because of cardiac dysfunction. Unfortunately, monitoring cardiovascular function at the time of the SBT is complex. The aim of our study was to explore if central venous pressure (CVP) changes were related to weaning failure after starting an SBT. We hypothesized that an early rise on CVP could signal a cardiac failure when handling a massive increase on venous return following a discontinuation of positive pressure ventilation. This CVP rise could identify a subset of patients at high risk for extubation failure. METHODS: Two-hundred and four mechanically ventilated patients in whom an SBT was decided were subjected to a monitoring protocol that included blinded assessment of CVP at baseline, and at 2 minutes after starting the trial (CVP-test). Weaning failure was defined as reintubation within 48-hours following extubation. Comparisons between two parametric or non-parametric variables were performed with student T test or Mann Whitney U test, respectively. A logistic multivariate regression was performed to determine the predictive value on extubation failure of usual clinical variables and CVP at 2-min after starting the SBT. RESULTS: One-hundred and sixty-five patients were extubated after the SBT, 11 of whom were reintubated within 48h. Absolute CVP values at 2-minutes, and the change from baseline (dCVP) were significantly higher in patients with extubation failure as compared to those successfully weaned. dCVP was an early predictor for reintubation (OR: 1.70 [1.31,2.19], p<0.001). CONCLUSIONS: An early rise in CVP after starting an SBT was associated with an increased risk of extubation failure. This might represent a warning signal not captured by usual SBT monitoring and could have relevant clinical implications.

Teoría Bifásica del Movimiento Dentario Aplicada Mediante Micro-Osteo-Perforaciones / Teeth Movement Bifasic Theory Applied by Micro-Osteo-Perforations

RESUMEN: Un desafío común en la ortodoncia es la realización de cierres de espacio en brechas largas con pérdida ósea significativa producto de extracciones tempranas, sitio de extracciones traumáticas o expansiones en adultos con tabla vestibular delgada. El propósito de este artículo es difundir una teoría del movimiento dental desarrollada a partir de una serie de investigaciones que intentan probarla en animales como seres humanos. Las dos fases de remodelación de hueso son la "activación - reabsorción" (proceso catabólico) y "activación-formación" (proceso anabólico) de las superficies del hueso, resultando en los cambios de tamaño, forma y posición del hueso. La inflamación es necesaria para el movimiento dentario. Se puede estimular ambas fases mediante pequeñas perforaciones del hueso que pueden ser realizadas de forma segura en la superficie vestibular o lingual de las tablas corticales pudiendo ser superficiales o profundas. Se muestran ejemplos clínicos de pacientes tratados con el enfoque de la Teoría bifásica mediante estimulación ósea transgingival. Se concluye que esta teoría bifásica permite explicar la favorable respuesta que se observa en situaciones clínicas complejas cuando se estimula el movimiento con micro-osteoperforaciones.

ABSTRACT: A common challenge in orthodontics is the task of space closures in long gaps with significant bone loss due to early extractions, site of traumatic extractions or expansions in adults with thin vestibular table. The purpose of this article is to disseminate a theory of dental movement developed from a series of investigations that try to test it in animals as human beings. The two phases of bone remodeling are the "activation - resorption" (catabolic process) and "activation-formation" (anabolic process) of bone surfaces, resulting in changes in bone size, shape and position. Inflammation is necessary for tooth movement. Both phases can be stimulated by small perforations of the bone that can be performed safely on the vestibular or lingual surface of the cortical boards, which may be superficial or deep. Clinical examples of patients treated with the biphasic theory approach by transgingival bone stimulation are shown. It is concluded that this biphasic theory allows to explain the favorable response observed in complex clinical situations when the movement is stimulated with micro-osteoperforations.

Condylar hyperplasia, diagnosis and clinical management: a clinical case report / Hiperplasia condilar, diagnóstico y manejo clínico: a propósito de un caso clínico

ABSTRACT Condylar hyperplasia is a disorder characterized by excessive and progressive growth affecting the condyle, neck, body, and mandibular ramus. Under this condition, mandibular growth occurs in all three planes of space, but more predominantly in one of them. Its etiology is controversial in its own. Some of its suggested causes include: trauma, hypervascularity, infections, and hereditary/intrauterine factors. Treatment protocols are varied, but one of the best treatment choices is high condylectomy. Following is the case of a 16-year-old female patient with this anomaly. The physical exam showed free facial asymmetry with mandibular deviation. Treatment consisted of TMJ surgery and high condylectomy plus a second orthodontic stage. The clinical outcomes at two-year follow-up suggest that a second intervention won′t be necessary. Patient was very satisfied with the results.

RESUMEN La hiperplasia condilar es una alteración caracterizada por crecimiento excesivo y progresivo, que afecta el cóndilo, el cuello, el cuerpo y la rama mandibular. Bajo esta condición, el crecimiento mandibular ocurre en los tres planos del espacio, pero con predominio por alguno de ellos. La etiología de la misma es motivo de controversia. Se sugieren como sus causas: traumatismos, hipervascularidad, infecciones y factores hereditarios e intrauterinos. Los protocolos de tratamiento son variados, pero una de las mejores opciones de tratamiento es la condilectomía alta. Se presenta el caso de una paciente de género femenino de 16 años de edad, portadora de esta anomalía. Al examen físico, se observa una franca asimetría facial con desviación mandibular. El tratamiento consistió en una cirugía de articulación temporomandibular con condilectomía alta y luego una segunda etapa ortodóntica. Los resultados clínicos a dos años de seguimiento sugieren que no será necesario hacer una segunda intervención. La paciente mostró alto grado de satisfacción con los resultados obtenidos.

Caracterización de los alambres termoactivados para uso ortodóncico: reporte de caso / Characterization of NitiCu wires for orthodontic use: a case report

Las aleaciones de cobre-níquel-titanio (NitiCu) se caracterizan por ser superelásticos con memoria de forma transformándose de un estado austenítico a uno martensítico a distintos grados de temperatura, a lo que se le denomina alambres termoactivados, ésta propiedad está siendo ampliamente utilizada en la ortodoncia. A continuación se realizará una revisión bibliográfica de estos alambres a propósito de un caso clínico.

The copper-nickel-titanium (NitiCu) are characterized by shape memory superelastic transforming from an austeNitic state to martensitic to a different temperature, to which heat activated wires is called, this property is widely used in orthodontics. Will be followed by a literature review of these wires on the subject of a clinical case.