Sheep bronchoscopy

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BACKGROUND: The development of bronchoscopic therapies for emphysema has renewed interest in collateral ventilation. The success or failure of bronchoscopically placed valves or biologic glues may be determined by collateral ventilation, which is exaggerated in emphysema. Furthermore, the validity of various animal models of emphysema for testing such techniques must be understood in the context of their species-specific collateral ventilation. OBJECTIVES: To quantify collateral ventilation in a sheep model of emphysema using a simple in vivo bronchoscopic method...

BACKGROUND: Biological lung volume reduction (BLVR) using biological reagents to remodel and shrink damaged regions of lung has previously been accomplished in sheep with experimental pulmonary emphysema. This report summarizes the initial clinical experience including a 3-month follow-up using this technique in humans. METHODS: An open-label phase 1 trial designed to evaluate the safety of BLVR in patients with advanced heterogeneous emphysema enrolled six patients...

The aim of the current study was to assess the safety of bronchoscopy-guided radiofrequency ablation (RFA) and compare the effectiveness between new internal cooled-RFA and standard noncooled-RFA. Normal lungs from sheep were used (n=6). Internal cooled-RFA and standard noncooled-RFA were set to assess the most suitable RFA conditions, such as power output, flow rate and ablation time. Internal cooled-RFA was then applied under the most optimal conditions of power output and flow rate for 15, 30, 60 and 120 s, and two water temperatures either room temperature (RT) water or cold water...

OBJECTIVE: To evaluate the effectiveness of bronchoscopic lung volume reduction (BLVR) using one way flap device in sheep model of heterogeneous emphysema. METHODS: Six 6-month sheep (weight: 20-30 kg) were treated with localized papain instillations to generate heterogeneous emphysema, subsequently underwent BLVR using one way-flap device at subsegment. Lung functional residual capacity (FRC) was analyzed before and 8 weeks after operation. Animals were euthanized at the 8-week time point...

The necessity of a cervical tracheal replacement arises with thyroid carcinoma, which occasionally infiltrates the trachea extensively, the rare primary tracheal tumors and, sporadically, benign stenoses. In the present study, we used an uncoated porous polypropylene prosthesis as cervical tracheal replacement in sheep. Specifically, we implanted a tracheal prosthesis of polypropylene mesh as a cervical tracheal replacement in five sheep, protecting the airways with self-expanding stents. Healing-in of the prostheses was checked bronchoscopically...

UNLABELLED: We evaluated an endobronchial valve device in the treatment of surgically created air leak or pneumothorax by eliminating antegrade flow. METHODS: Six sheep underwent general anesthesia with positive pressure ventilation and left thoracotomy. After division of the mediastinal pleura, the contralateral cranial lobe was identified and a 2.5 cmx1.5 cm laceration created with resultant air leak. Using bronchoscopy, we deployed a valve device in the bronchus of the injured segment...

BACKGROUND: Bronchoscopic methods for achieving lung volume reduction (BLVR) are presently undergoing clinical trials, and will soon be clinically available. Understanding the differential effects of surgical volume reduction therapy (LVRS) and BLVR on lung and chest wall physiology will assist physicians in selecting an optimal approach for patients. OBJECTIVES: Determine whether LVRS adversely affects lung or chest wall physiology at 3-month follow-up relative to BLVR in an experimental model of sheep emphysema...

STUDY OBJECTIVES: Significant morbidity and mortality offset the benefits of lung volume reduction surgery (LVRS) for emphysema. By contributing to distal lung collapse, bronchoscopic placement of valved prostheses has the potential to noninvasively replicate the beneficial effects of LVRS. The purpose of this study was to investigate the safety and feasibility of placing valves in segmental airways of patients with emphysema. DESIGN: Case series. SETTING: Tertiary hospital, severe airways disease clinic...

We investigated a new method of pulmonary ventilation that included a minitracheostomy, a reverse thrust catheter to deliver continuous flow of gas to the carina, and a threshold valve to avoid lung overinflation. In six lightly sedated healthy sheep, at a continuous flow of 5, 10, or 15 L/min and a threshold valve of 5, 10, 15, or 20 cm H(2)O, we observed a novel respiratory pattern that was characterized either by active lung inflation followed by passive and prolonged inspiratory hold (mixed pattern) or by an absence of all active inspiratory effort and only passive inflation of the lungs (passive pattern)...

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Bronchoscopic lung volume reduction (BLVR), a minimally invasive procedure based on tissue engineering principles, was performed in six sheep with papain-induced experimental emphysema (EMPH). Physiologic measurements, at baseline, after generation of EMPH, and at 3 and 9 weeks after BLVR, included lung volumes, diffusing capacity (DL(CO)), pressure-volume relationships for the lung and chest wall, pleural pressures generated during active respiratory muscle contraction, lung resistance and dynamic elastance...

Lung volume reduction surgery (LVRS), the removal of damaged, hyperexpanded lung, has been shown to improve respiratory function in many patients with end-stage emphysema. We report the results of an animal study using a new transbronchoscopic alternative to LVRS in which a washout solution and fibrin-based glue are used to collapse, seal, and scar target regions of abnormal lung. Twelve sheep had static and dynamic lung functions measured at baseline. Emphysema was produced by inhaled papain (7,000 U/wk x 4 wk), resulting in a significant increase of lung volumes, compliance, and airway resistance...

BACKGROUND: A variety of respiratory stents are currently available, but the ideal airway prosthesis seems far from being recognized. The objective of this study was to verify safety and long-term effect on the bronchial wall of three different types of airway stents. METHODS: Twelve healthy adult sheep were divided in three groups, scheduled to receive: (1) bare self-expandable metallic stents (Gianturco); (2) silicone stents (Dumon); and (3) covered self-expandable synthetic stents (Polyflex)...

Flow limitation during forced exhalation and gas trapping during high-frequency ventilation are affected by upstream viscous losses and by the relationship between transmural pressure (Ptm) and cross-sectional area (A(tr)) of the airways, i.e., tube law (TL). Our objective was to test the validity of a simple lumped-parameter model of expiratory flow limitation, including the measured TL, static pressure recovery, and upstream viscous losses. To accomplish this objective, we assessed the TLs of various excised animal tracheae in controlled conditions of quasi-static (no flow) and steady forced expiratory flow...

The purpose of this study was to evaluate a surfactant based on a recombinant surfactant protein-C (rSP-C) at three different doses (25, 100, and 200 mg lipid/kg) in the saline lavage adult sheep model of acute lung injury. All three doses resulted in significant improvements in gas exchange, although the 100 and 200 mg/kg doses were superior to the 25 mg/kg dose. There were no significant differences in effect of the 100 and 200 mg/kg doses. In addition, the physiologic efficacy and lobar surfactant distribution patterns were similar when two different surfactant delivery methods were compared...

OBJECTIVE: Bronchoscopy and lavage are used to confirm diagnosis and can be therapeutic in patients suffering inhalation injury. Lavage is traditionally performed using saline, which is unfortunately associated with profound transient hypoxemia. Perfluorocarbons, having a high gas solubility for oxygen and carbon dioxide, increase oxygenation when instilled into the airway. We hypothesized that the use of perfluorocarbons for bronchoscopic lavage would attenuate this transient hypoxemia...

The authors evaluated the relative importance of the following scanning parameters at computed tomographic bronchoscopy in an anesthetized adult sheep's thorax: section thickness (2, 4, 8 mm), pitch (1.0, 1.5, 2.0), milliampere setting (100, 175, 250 mA), and overlap of reconstructed sections (0%, 25%, 50%, 75%). Five blinded readers ranked the images twice in comparison with photographs of the mounted specimen. Differences in image quality were significant (P < .001) with section thickness of 2 mm and a pitch of 1...

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PURPOSE: Expandable metallic stents (Palmaz stents) have been used in the treatment of tracheobronchial obstruction in children and adults. The authors investigated their utility in the management of acute airway stenosis in a growing animal model. METHODS: A model for tracheal stenosis was developed in young lambs (mean age, 4 weeks; mean weight, 8.6 kg). Via an anterior tracheotomy, a circumferential mucosal injury to the trachea was produced with electrocautery in 31 lambs...