Prevalence and Implications of Abnormal Respiratory Patterns in Cardiac Surgery: A Prospective Cohort Study.

OBJECTIVE: To investigate the prevalence and impact of abnormal respiratory patterns in cardiac surgery patients. DESIGN: Prospective cohort study. SETTING: Tertiary hospital. PARTICIPANTS: Patients scheduled for elective coronary artery bypass graft surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Pulmonary function tests were performed in 454 patients before surgery. Abnormal respiratory patterns were defined as follows: obstructive (forced expiratory volume in 1 s [FEV1]/forced vital capacity [FVC]<0.70), restrictive (FEV1/FVC≥0.70 and FVC<80% of predicted), and mixed (FEV1/FVC<0.70 and both FEV1 and FVC<80% of predicted). Of the 31 patients with a history of chronic obstructive pulmonary disease, no abnormal respiratory pattern was confirmed in 5. Of the 423 patients without a history of lung disease, the authors newly identified 57 obstructive, 46 restrictive, and 4 mixed patterns. Therefore, lung disease was reclassified in 24.7% of cases. Independent predictors of obstructive pattern were age, male sex, history of smoking, and chronic obstructive pulmonary disease. Obstructive lung disease was associated with 16 hours or longer ventilation. A reduced FEV1 was associated with a likelihood of atrial fibrillation (1-L decrement, odds ratio: 1.38, 95% confidence interval: 1.01-to-1.90, p = 0.04) and hospitalization time (regression coefficient: 1.23, 95% confidence interval: 0.54-to-1.91, p<0.001). CONCLUSIONS: Abnormal respiratory patterns are common and often underdiagnosed in the cardiac surgery setting. Pulmonary function tests help reveal patients at risk of complications and may provide an opportunity for intervention.

Seismocardiography: past, present and future.

This paper presents an overview of seismocardiography (SCG) as a noninvasive cardiology method. The paper represents a brief historical background to the SCG, an assessment of the technology at present, and an evaluation of the challenges we must address. These challenges include the development and clarification of definitions, standards, and annotations.

Endothelial function testing.

It has been shown that the presence of well-preserved brachial artery vasoreactivity predicts the absence of coronary artery disease. The recent findings that coronary endothelial dysfunction is associated with an increased risk of stroke or transient ischemic attack in middle-aged patients without coronary artery disease support the concept that endothelial dysfunction is a systemic and prognostically relevant disorder and assessment of endothelial function may play a role as an additional strategy to identify patients who would benefit from aggressive preventive measures. It remains unknown whether an improvement in endothelial function directly translates into improved outcome.

Monitoring body fat in the elderly: application of air-displacement plethysmography.

PURPOSE OF REVIEW: This review will focus chiefly on recently published studies utilizing air-displacement plethysmography (i.e. BOD POD) in geriatric populations. This innovative technology has been available commercially since 1995. As the test procedure is relatively easy to perform and quick, it may provide an improvement in body composition testing, especially in older individuals with poor ambulation and health. RECENT FINDINGS: This review will explain in a concise and detailed manner the underlying principles of air-displacement plethysmography specifically related to the BOD POD. Second, it will review the studies using this new technology in comparison with more commonly used techniques (hydrostatic weighing, dual energy X-ray absorptiometry, deuterium oxide, multi-compartmental models) for body composition analysis in geriatric populations. Third, it will provide a direction for future studies. SUMMARY: A review of the current body of literature in which air-displacement plethysmography was used is beginning to emerge with a clear picture. Although this technique is still new, it appears that air-displacement plethysmography is a valid and reliable alternative to more traditional body composition techniques, as indicated by small mean differences between techniques. This has special implications in a geriatric population because traditional techniques are difficult to perform in individuals with joint pain, ambulation issues, and overall poor health.

Validación de la pletismografía de impedancia como pruba diagnóstica de la trombosis venosa profunda proximal de miembros inferiores: estudio de concordancia entre venografía y pletismografía

Introducción: La trombosis venosa profunda proximal de miembros inferiores (TVPPMI) es una entidad potencialmente mortal; de la rapidez del diagnóstico y la intervención depende el curso y complicaciones de la enfermedad. El diagnóstico por pletismografía de impedancia facilita el seguimiento y la conducta terapéutica; sin embargo, su sensibilidad y especificidad ha sido cuestionada y se propone el reemplazo por otros métodos no invasivos (doppler venoso). Objetivos: Determinar la sensibilidad y especificidad de la pletismografía de impedancia de miembros inferiores en el diagnóstico de la TVPPMI en pacientes con clínica o con factores de riesgo para esta enfermedad en el Hospital Universitario San Ignacio. Diseño: estudio de concordancia entre la venografía (patrón de oro) y la pletismografía de impedancia (IPG). Pacientes y Métodos: Entre febrero de 1994 y marzo de 1995 ingresaron 62 pacientes con clínica de TVPPMI o con factores de riesgo para la enfermedad al servicio de Medicina Interna o al Departamento del Radiología del Hospital Universitario San Ignacio. Se diligenció una historia clínica haciendo énfasis en los factores de riesgo y en el diagnóstico; se les realizó pletismografía de impedancia de miembros inferiores y posteriormente una venografía. Resultados: Se incluyeron 62 sujetos, de los cuales ocho se excluyen y se analizan un total de 54 pacientes. El 11 por ciento presentaban historia clínica de trombosis venosa profunda y el grupo restante, factores de riesgo para adquirir la enfermedad. La sensibilidad de la IPG en el diagnóstico de TVPPMI del grupo en general fue del 100 por ciento con especificidad de 92 por ciento, con un valor predictivo positico del 33 por ciento. En pacientes con sospecha clínica la sensibilidad fue del 100 por ciento y la especificidad del 90 por ciento; en pacientes sin clínica pero con factores de riesgo no se pudo calcular la sensibilidad y la especificidad fue del 90 por ciento. Conclusión: En pacientes con sospecha clínica de TVPPMI, la IPG tiene alta sensibilidad como método diagnóstico; su valor predictivo positivo en este estudio es bajo por el tamaño de la muestra. Se debe continuar el estudio incluyendo más pacientes con clínica o con alto riesgo de tener TVPPMI.

Plethysmography. A treatise on its evolution, differential methodology and clinical utilization. 1973.

Plethysmography is the observation and use of volume changes in physiologic entities. The most influential short-term effect is caused by the pulsatile flow of blood. Attempts to convert these pulsatile volume changes into minimum required blood flow per unit of time have been successful clinically. Plethysmography can be accomplished by encapsulating digits, limbs and entire bodies. Volume changes in the member cause volume changes in the fixed chamber which then influences an observational medium. Plethysmography can also be accomplished with a strain gauge, direct application of electricity to flesh, changing opacity effects on tissue, ultrasound (the Doppler effect) or the piezoelectric method. The piezoelectric plethysmograph was successfully tested on 55 patients.

Plethysmography: history and recent advances.

A short historical note on plethysmography is given and the development of the modern computerized pneumoplethysmograph is described. The computer-aided pneumoplethysmogram (CAP), with proper programming, makes possible numerous computations that give new, useful, and rapid information about the patient. New applications of the CAP will quickly develop and the data collected will be quickly analyzed and displayed.

Plethysmography: history and recent advances.

A short historical development of pneumoplethysmography and its clinical usefulness has been given and the older instruments have been compared with a modern computerized pneumoplethysmograph. The computer aided plethysmogram, with proper programming, makes possible numerous computations which give new and useful information about the circulation. New applications of the CAP will quickly develop and the data collected will be only limited by the imagination.