Assisted Ventilation: Physiologic Implications and Complications

Greenspan, Jay S.; Shaffer, Thomas H.; Fox, William W.; Spitzer, Alan R.

doi:10.1016/b978-0-7216-9654-6.50099-0

Cited by 9 publications

(9 citation statements)

References 126 publications

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“…The resultant pressure profiles associated with the step volume increments were recorded and injected volume units were normalized to resting segment volume. Bulk modulus (K) was calculated from pressure-volume data using the formula in Equation (1). In this equation, Dp is the change in pressure, DV is the infused volume, and V is the resting volume.…”

Section: Static Pressure-volume Relationships and Bulk Modulusmentioning

confidence: 99%

“…A great emphasis in neonatology is placed on the chronic lung disease that results from mechanical ventilation (MV), but typically, ventilated infants also suffer from chronic disease of the conducting airways. 1 As with lung disease, the chronic phases of airway disease are likely subsequent to acute trauma and the disruption of mechanical properties of the tissue/organ. During the fetal and neonatal periods, there are developmental changes in the structure and functional properties of the airways, [2][3][4][5] which are in opposition to that of the lung with respect to compliance.…”

Section: Introductionmentioning

confidence: 99%

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Sequential alterations of tracheal mechanical properties in the neonatal lamb: Effect of mechanical ventilation

Miller

Zhu

Altman

et al. 2006

Pediatric Pulmonology

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Section: Static Pressure-volume Relationships and Bulk Modulusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Sequential alterations of tracheal mechanical properties in the neonatal lamb: Effect of mechanical ventilation

Miller

Zhu

Altman

et al. 2006

Pediatric Pulmonology

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“…To reproduce these conditions, a few adaptations in scripted parameters were needed: 1) matching to reported timeline; 2) representation of artificial ventilation with a positive average intrathoracic pressure of ϩ2 mm Hg (instead of Ϫ3 mm Hg). Intrathoracic pressure is positive throughout inspiration and remains slightly positive, whenever positive end-expiratory pressure is applied (15,37); and 3) delayed rise in DA resistance, corresponding to the initiation of ventilation with 100% oxygen. In these conditions, simulation results match the target data.…”

Section: Discussionmentioning

confidence: 99%

“…At birth, the fluid in the bronchoalveolar tract is replaced by air. In spontaneously breathing newborns, the diaphragm contracts during inspiration, thereby lowering the intrathoracic pressure toward negative values of approximately Ϫ3 mm Hg (14,15).…”

Section: Methodsmentioning

confidence: 99%

A Model for Educational Simulation of Hemodynamic Transitions at Birth

et al. 2010

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Birth is characterized by swift and complex transitions in hemodynamic and respiratory variables. Unrecognized pathologies or incidents may quickly become fatal or cause permanent damage. This article introduces an essential component of an acute perinatal care simulator, namely a model for educational simulation of normal hemodynamic transitions seen during and shortly after birth. We explicitly formulate educational objectives and adapt a preexisting model for the simulation of neonatal cardiovascular physiology to include essential aspects of fetal hemodynamics. From the scientific literature, we obtain model parameters that characterize these aspects quantitatively. The fetal model is controlled by a time-and event-based script of changes occurring at birth, such as onset of breathing and cord clamping, and the transitory phase up to 24 h after birth. Comparison of simulation results with published target data confirms that realistic simulated hemodynamic vital signs are achieved. (Pediatr Res 67: 158-165, 2010) P erinatal acute care is associated with specific clinical demands and challenges. The relatively small number of acute care cases occurring in many institutions, together with the presence of senior staff assuming the responsibility for their management, may hinder the establishment of adequate training for less experienced individuals. In other areas of acute care medicine, realistic simulators contribute to training of healthcare professionals and to patient safety.Clinically relevant learning objectives for medical staff in Neonatology include the recognition of cardiovascular signs and symptoms occurring in pathologies that manifest shortly after birth, such as persistent pulmonary hypertension, left ventricular overload by a patent ductus arteriosus (DA), myocardial depression, and hemorrhage.This article introduces a fundamental component of a perinatal acute care simulator, namely a simulation engine, for normal hemodynamic transitions from the fetal to the early neonatal period. A simulation engine can contribute to a life-like training environment by providing real-time, automatic evolution of clinical signs and monitored signals and of their response to therapeutic interventions. To be able to simulate normal physiology and provide a platform for future simulation of the above-mentioned incidents and pathologies, it is necessary that the engine reflect essential aspects of fetal hemodynamics and its subsequent transition to the neonate. Among others, structures such as lungs, placenta, heart, systemic arterial circulation, and the various fetal shunts need to be included. The simulation engine should be able to simulate realistic blood pressures and flow rates in these structures during fetal, transitional, and neonatal periods. METHODSThe proposed simulation engine for normal hemodynamic transitions from the fetal to the early neonatal period consists of a fetal hemodynamic model controlled by a time-and event-based script (1). The script triggers events occurring at birth such ...

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“…As the only passage for the air to flow in and out, tracheal collapse behavior is very important for estimating the bio-function of the whole respiratory system, on which many clinical parameters are dependent, such as compliance and stress. Changes in biomechanical properties and composition of tracheal cartilage may contribute to altered lung function in respiratory diseases, such as chronic obstructive pulmonary disease (COPD) in which weakening of the wall structures of large airways has been found, and tracheobronchomalacia (TBM) where altered cartilage geometry and elasticity appear to play a role [1][2][3]. An understanding of that physiological pressure could induce a prominent interaction between the structure and the flow for the bio-function of the whole respiratory system [4].…”

Section: Introductionmentioning

confidence: 98%

An ultrasound imaging method for in vivo measurement of tracheal elasticity

Chen

Chu

et al. 2008

2008 IEEE Ultrasonics Symposium

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The mechanical properties of trachea can reflect the bio-function and may represent the changes of compliances and stifinesses of airway. Therefore, the difference of airway mechanical properties between the normal people and the patients with airway disease can be observed in clinic. The objective of this paper is to determine the trachea elasticity of normal people by non-invasive ultrasound imaging method in statistic pressure. The measurement was involved 9 normal subjects (age from 23 to 40, 4 males and 5 females) and 2 patients (age from 23 to 40, 2 males). A Threshold Positive Expiratory Pressure device (Threshold PEP, New Jersey, USA) was used to provide positive expiratory pressure therapy. All subjects were asked to breathe through a mouthpiece. Then, 5 different loads of PEP were applied to the range from 0 cmH 2 O to 20 cmH 2 O and in a scale of 5 cmH 2 0. A clinical ultrasound system ( Terason 2000 Burlington, MA ,USA) with a 7 MHz transducer for measuring the mean diameter of trachea anteroposterior and transverse from thyroid cartilage and suprosternal notch. Finally, the ultrasound imaging was captured and analyzed by calculating the elasticity, Young's Modulus, which was taking the ratio of stress over strain. The Intra-class correlation coefficients were employed to verify the reliablity for the experiment. Our result shows that the elasticity of normal subject tracheal were in the range of 145~981kPa, the abnormal subject were in the range of 69~108kPa, and the Intra-class correlation coefficients were in the range 0.8~0.99. In this study, we demonstrate the use of ultrasound imaging for measuring airway mechanical property and we also observed significant difference of the stress to strain experiments between normal subject and abnormal subject. This paper provides a new approach to measure the elasticity of human tracheal in real time, patient-friendly way.

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Assisted Ventilation: Physiologic Implications and Complications

Cited by 9 publications

References 126 publications

Sequential alterations of tracheal mechanical properties in the neonatal lamb: Effect of mechanical ventilation

Sequential alterations of tracheal mechanical properties in the neonatal lamb: Effect of mechanical ventilation

A Model for Educational Simulation of Hemodynamic Transitions at Birth

An ultrasound imaging method for in vivo measurement of tracheal elasticity

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