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Respiratory Compliance (respiratory + compliance)
Selected AbstractsMeasurements of functional residual capacity during intensive care treatment: the technical aspects and its possible clinical applicationsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2009H. HEINZE Direct measurement of lung volume, i.e. functional residual capacity (FRC) has been recommended for monitoring during mechanical ventilation. Mostly due to technical reasons, FRC measurements have not become a routine monitoring tool, but promising techniques have been presented. We performed a literature search of studies with the key words ,functional residual capacity' or ,end expiratory lung volume' and summarize the physiology and patho-physiology of FRC measurements in ventilated patients, describe the existing techniques for bedside measurement, and provide an overview of the clinical questions that can be addressed using an FRC assessment. The wash-in or wash-out of a tracer gas in a multiple breath maneuver seems to be best applicable at bedside, and promising techniques for nitrogen or oxygen wash-in/wash-out with reasonable accuracy and repeatability have been presented. Studies in ventilated patients demonstrate that FRC can easily be measured at bedside during various clinical settings, including positive end-expiratory pressure optimization, endotracheal suctioning, prone position, and the weaning from mechanical ventilation. Alveolar derecruitment can easily be monitored and improvements of FRC without changes of the ventilatory setting could indicate alveolar recruitment. FRC seems to be insensitive to over-inflation of already inflated alveoli. Growing evidence suggests that FRC measurements, in combination with other parameters such as arterial oxygenation and respiratory compliance, could provide important information on the pulmonary situation in critically ill patients. Further studies are needed to define the exact role of FRC in monitoring and perhaps guiding mechanical ventilation. [source] Postbypass pulmonary artery pressure influences respiratory system compliance after ventricular septal defect closurePEDIATRIC ANESTHESIA, Issue 4 2000Muneyuki Takeuchi MD It is reported that surgical correction of left-to-right shunt improves respiratory function in paediatric cardiac patients. However, such correction sometimes does not result in an improvement of respiratory compliance. The purpose of this study was to look for factors determining changes in respiratory system compliance (Crs) in patients who underwent closure of ventricular septal defect (VSD closure). In a prospective study, 17 children (< 10 kg) who underwent VSD closure were enrolled. They were divided into two groups, according to postbypass mean pulmonary artery pressure (mPAP). The patients were allocated to Group C if mPAP was , 18 mmHg (n=12) and to Group PH if > 18 mmHg (n=5). We compared the ratio of postoperative Crs to preoperative Crs (Cpost/Cpre) between the groups. A multiple occlusion technique was used to measure Crs. The Cpost/Cpre in group C was larger than that in group PH (1.11 ± 0.17 vs. 0.81 ± 0.12, P < 0.01). There was a correlation between postbypass mPAP and Cpost/Cpre (rs=0.49, P < 0.05), but no correlation was noted between preoperative mPAP, Qp/Qs or Rp/Rs and Cpost/Cpre. We concluded that high postbypass mPAP was associated with a perioperative decrease in Crs after VSD closure. [source] Lung function tests in neonates and infants with chronic lung disease: Lung and chest-wall mechanicsPEDIATRIC PULMONOLOGY, Issue 4 2006Monika Gappa MD This is the fifth paper in a review series that summarizes available data and critically discusses the potential role of lung function testing in infants and young children with acute neonatal respiratory disorders and chronic lung disease of infancy (CLDI). This review focuses on respiratory mechanics, including chest-wall and tissue mechanics, obtained in the intensive care setting and in infants during unassisted breathing. Following orientation of the reader to the subject area, we focused comments on areas of enquiry proposed in the introductory paper to this series. The quality of the published literature is reviewed critically with respect to relevant methods, equipment and study design, limitations and strengths of different techniques, and availability and appropriateness of reference data. Recommendations to guide future investigations in this field are provided. Numerous different methods have been used to assess respiratory mechanics with the aims of describing pulmonary status in preterm infants and assessing the effect of therapeutic interventions such as surfactant treatment, antenatal or postnatal steroids, or bronchodilator treatment. Interpretation of many of these studies is limited because lung volume was not measured simultaneously. In addition, populations are not comparable, and the number of infants studied has generally been small. Nevertheless, results appear to support the pathophysiological concept that immaturity of the lung leads to impaired lung function, which may improve with growth and development, irrespective of the diagnosis of chronic lung disease. To fully understand the impact of immaturity on the developing lung, it is unlikely that a single parameter such as respiratory compliance or resistance will accurately describe underlying changes. Assessment of respiratory mechanics will have to be supplemented by assessment of lung volume and airway function. New methods such as the low-frequency forced oscillation technique, which differentiate the tissue and airway components of respiratory mechanics, are likely to require further development before they can be of clinical significance. Pediatr Pulmonol. © 2006 Wiley-Liss, Inc. [source] Lung Function Tests in Neonates and Infants with Chronic Lung Disease of Infancy: Functional Residual CapacityPEDIATRIC PULMONOLOGY, Issue 1 2006Georg Hülskamp MD Abstract This is the second paper in a review series that will summarize available data and discuss the potential role of lung function testing in infants and young children with acute neonatal respiratory disorders and chronic lung disease of infancy. The current paper addresses the expansive subject of measurements of lung volume using plethysmography and gas dilution/washout techniques. Following orientation of the reader to the subject area, we focus our comments on areas of inquiry proposed in the introductory paper to this series. The quality of the published literature is reviewed critically, and recommendations are provided to guide future investigation in this field. Measurements of lung volume are important both for assessing growth and development of lungs in health and disease, and for interpreting volume-dependent lung function parameters such as respiratory compliance, resistance, forced expiratory flows, and indices of gas-mixing efficiency. Acute neonatal lung disease is characterized by severely reduced functional residual capacity (FRC), with treatments aimed at securing optimal lung recruitment. While FRC may remain reduced in established chronic lung disease of infancy, more commonly it becomes normalized or even elevated due to hyperinflation, with or without gas-trapping, secondary to airway obstruction. Ideally, accurate and reliable bedside measurements of FRC would be feasible from birth, throughout all phases of postnatal care (including assisted ventilation), and during subsequent long-term follow-up. Although lung volume measurements in extremely preterm infants were described in a research environment, resolution of several issues is required before such investigations can be translated into routine clinical monitoring. Pediatr Pulmonol. © 2005 Wiley-Liss, Inc. [source] Feedback withdrawal and changing compliance during manual hyperinflationPHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 2 2002Julie Hila Abstract Background and Purpose The performance of manual hyperinflation by physiotherapists can be improved by the availability of a pressure manometer. The present study aimed to test whether these benefits could be maintained when the manometer is withdrawn and whether the availability of a manometer affects the pressures delivered under changing respiratory compliances. Method Manual hyperinflation breaths were delivered to a test lung by student physiotherapists, with a target peak airway pressure of 30 cm H2O under control, feedback and feedback-withdrawal conditions. The breaths were delivered for three trials under each testing condition at each of three respiratory compliance settings. Results The availability of augmented feedback increased the accuracy and reduced the variability of performance; however, these improvements were not maintained when feedback was withdrawn. Changing respiratory compliance significantly affected the accuracy and variability during the control and withdrawal conditions, but the availability of a manometer negated these differences. Conclusions The availability of a pressure manometer negates the influence of respiratory compliance on the achievement of target peak airway pressures during manual hyperinflation in the laboratory environment, however these benefits are not retained when feedback is withdrawn. Therefore, it is recommended that a pressure manometer should be routinely available during manual hyperinflation in clinical practice to optimize treatment safety and effectiveness. Copyright © 2002 Whurr Publishers Ltd. [source] | ||||||||||