Introduction: Acute respiratory distress syndrome (ARDS), seen in critically ill patients, is a disease process that affects the lungs and directly impacts a patient’s oxygenation. Despite treatment, patients often die of ARDS secondary to systemic complications. Prone positioning has been introduced as a treatment to improve the outcomes of ARDS patients. This thesis summarized and critiqued recent literature on the outcomes of prone positioning in ARDS patients. Methodology: An initial literature search was conducted using CINAHL Plus with Text, Medline, Cochrane Database of Systematic Reviews, and US National Library of Medicine National Institutes of Health. Multiple search terms were used. Inclusion criteria consisted of peer reviewed research articles, academic journal articles, and evidence-based research or practices published within the last ten years. All studies included adult subjects and were published in the English language. Studies that did not address patient outcomes such as mortality, length of stay, or hemodynamic oxygenation were excluded from the review. Results: The review of literature contains one meta-analysis and two studies. Data indicated that prone positioning was statistically significant in reducing mortality when performed in sessions of 12 hours or longer (p=0.05). Hemodynamic oxygenation improved significantly after at least 48 hours of implementing prone positioning. There was no trend in the length of stay or duration in mechanical ventilation whether supine or prone positioning was used. Complications such as endotracheal tube dislodgement, incidence of ventilator-associated pneumonia, and pressure ulcers were reported in both supine and prone position with an increased risk of pressure ulcers and endotracheal tube obstruction in the prone position groups. Conclusions: Findings support a benefit in patient outcomes in patients placed in prone position with ARDS. Mortality was reduced when prone sessions lasted longer than 12 hours possibly due to the improvement in patient oxygenation 48 hours after initiation of prone positioning intervention. Further research is needed to solidify these findings and establish guidelines and optimal procedural methods to maximize patient outcomes and lower the incidence of patient complications.

No description available.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / Airborne instrumentation used during flight tests is being installed and maintained in a unique way by operational bomber testers from the Air Force’s 53d Wing. The ability of the flight test community to test on operational aircraft has always been somewhat curtailed by the need for advanced forms of instrumentation. Operational fighter flight test squadrons have aircraft assigned to them, which they modify on as needed basis, much the same as developmental testers. However, bomber operational test units must use operational aircraft to accomplish their mission as there are no bombers in the Air Force’s Air Combat Command (ACC) specifically set aside for operational tests. During test missions, these units borrow aircraft from operational bomb wings, and then return them to service with the bomb wing after testing is complete. Yet, the requirement for instrumentation on these test missions is not much different than that of developmental testers. The weapon system engineer’s typically require Mil-Std-1553, video, telemetry, and Global Positioning System (GPS) Time-Space-Position-Information airborne receiver recordings. In addition, this data must be synchronized with an IRIG-B time code source, and recorded with the same precision as the data gathered during development test and evaluation (DT&E). As a result, several techniques have been developed, and instrumentation systems designed for these operational test units to incorporate instrumentation on operational aircraft. Several factors hamper the usual modification process in place at bases such as Edwards AFB and Eglin AFB. Primary among these is the requirement to maintain the aircraft in an operational configuration, and still meet all of the modification design safety criteria placed on the design team by the aircraft’s single manager. Secondary to the list of restrictions is modification time. Aircraft resources are stretched quite thin when one considers all of the bomb wing’s operational commitments. When they must release an aircraft for test missions, the testers must insure that schedule impacts are minimal. Therefore, these systems must install and de-install within one to two days and be completely portable. Placing holes in existing structures or adding new permanent structure is unacceptable. In addition, these aircraft must be capable of returning to combat ready status at any time. This paper centers on the B-52 bomber, and the active aircraft temporary modifications under control of the 49th Test Squadron (49 TESTS) at Barksdale AFB in Louisiana. The B-52 presents unique design challenges all its own, in addition to the general restrictions already mentioned. This paper will present the options that the 49 TESTS has successfully used to overcome the aforementioned restrictions, and provide an appropriate level of specialized instrumentation for its data collection requirements.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Le syndrome de détresse respiratoire aiguë (SDRA) se développe suite à une atteinte pulmonaire lésionnelle, induisant un œdème et une inflammation excessive, généralement suivis d’une réparation atypique menant à la fibrose. Malgré de signifiants progrès dans les traitements, la mortalité reste élevée : ~ 40 %. Mon hypothèse de travail est que l’atténuation de l’œdème ou de la réponse inflammatoire pourrait freiner le développement ou la sévérité de la phase exsudative. Nous avons évalué cette hypothèse à l’aide d’un modèle de phase exsudative du SDRA, i.e. instillation intra-trachéale de bléomycine, chez les souris.  La modulation des fluides alvéolaires est étudiée avec des souris transgénique (Tg) pour le canal ENaC, qui sont sensibles à la formation d’un œdème. Cependant, ces souris Tg ne sont pas plus sensibles au développement de la phase exsudative en condition lésionnelle (bléomycine). Nous avons déterminé par une étude électrophysiologique des cellules épithéliales alvéolaires de type II (AT II) que ce n’est pas lié à une inhibition par la bléomycine de la fonction du canal ENaC.  Le traitement de la réponse inflammatoire associée au SDRA par des glucocorticoïdes est une thérapie potentielle mais controversée. Les glucocorticoïdes dans notre modèle murin ne réduisent pas la sévérité des lésions. Nous avons pu déterminé lors d’expériences in vitro que ce serait dû à une réduction de la capacité de réparation des AT II. En résumé :  La modulation du canal ENaC ne modifie pas le développement de la phase exsudative, suggérant que la régulation de l’œdème n’est pas suffisante pour modifier l’évolution du SDRA.  La modulation de l’inflammation par les glucocorticoïdes est ineffective, possiblement à cause d’une altération de la réparation. Mon étude suggère que le traitement de la phase exsudative du SDRA est complexe. En effet, la régulation de l’œdème ou de l’inflammation de façon isolée ne peut pas modifier l’évolution du SDRA. L'hétérogénéité des sources du SDRA et la redondance des mécanismes cellulaires impliqués dans l’évolution des lésions pulmonaires suggèrent que le traitement nécessitera une approche visant plusieurs cibles mécanistiques afin d’en accélérer la résolution. / Although much has been learned about the mechanisms leading to acute respiratory distress syndrome (ARDS), mortality remains high: ~ 40%. This syndrome is associated with lung injury where alveolar edema and excessive inflammatory response can progress to abnormal epithelial repair and fibrosis. The hypothesis of the work presented in this thesis is that attenuation of edema or of the inflammatory response in the initial stage of the acute lung injury would decrease the severity of injury. I evaluated this hypothesis in an ARDS acute phase, modeled by an intratracheal instillation of bleomycin in mice, using two distinct experimental strategies.  The importance of edema clearance was studied in a transgenic (Tg) ENaC mouse, a mouse known to be sensitive to the formation of edema. However, our results show that these Tg mice were not more susceptible to the development of the ARDS acute phase induced by bleomycin. Furthermore, we have been able to show that bleomycin itself did not interfere with the ENaC channel function of alveolar epithelial cells type II (AT II).  The treatment of the inflammatory response associated with ARDS by glucocorticoid therapy is subject to controversy. In our mouse model, glucocorticoids decrease the level of cytokine in the alveolar milieu but did not decrease the severity of lung injury. Using in vitro experiments, we show that this lack of response could be secondary to the impact of the treatment on the epithelial repair capacity of AT II. In summary:  The ENaC channel expression did not have an impact on the development of the exudative phase, suggesting that the regulation of edema is not sufficient to alter the course of ARDS.  The modulation of inflammation by glucocorticoids was ineffective, possibly because of impaired repair of the epithelium. These results suggest that the control of edema or inflammation separately does not modify the evolution of lung injury. The heterogeneity of the ARDS origins and the redundancy of cellular mechanisms involved in lung injury will require therapy aimed at multiple pathophysiological targets to permit the resolution of lung injury.

A isquemia/reperfusão intestinal (I/R-i) se associa ao desenvolvimento de inflamação pulmonar aguda, que pode ser modulada por mediadores inflamatórios presentes na linfa. Avaliamos os efeitos da I/R-i sob a inflamação pulmonar e a participação do sistema linfático. Wistar machos foram submetidos a 45 min de isquemia intestinal e 24, 72 ou 120 h de reperfusão. Outro grupo teve o ducto linfático bloqueado antes da isquemia. Os resultados revelaram maior inflamação pulmonar nos animais reperfundidos por 120 h em relação aos outros períodos de reperfusão estudados. Os animais apresentaram aumento de MPO e permeabilidade. Aumento de VEGF e de IL-1<font face=\"Symbol\">&#946 e diminuição de IL-10 no explante pulmonar. Diminuição de vWf e aumento de integrina <font face=\"Symbol\">&#9461, PECAM-1 e colágeno I e IV no endotélio pulmonar. Os dados indicam que mecanismos temporais modulam a resposta inflamatória decorrente da I/R-i. Mediadores na linfa e na circulação participam do desencadeamento/manutenção da inflamação pulmonar alterando a integridade do endotélio e ativando o pulmão que libera mediadores adicionais. / Intestinal ischemia/reperfusion (i-I/R) is associated with the development of acute lung inflammation, which can be modulated by inflammatory mediators present in the lymph. We evaluated the effects of i-I/R in lung inflammation and the involvement of the lymphatic system. Wistar rats were subjected to 45 min of intestinal ischemia and 24, 72 or 120 h of reperfusion. Another group had the lymphatic duct blocked before ischemia. The results revealed greater lung inflammation in animals reperfused for 120 h in comparison to other periods studied. These animals showed increased MPO and permeability. Increased VEGF and IL-1<font face=\"Symbol\">&#946 and decreased IL-10 in lung explants. Decreased vWf and increased <font face=\"Symbol\">&#9461 integrin, PECAM-1 and collagen I and IV in the pulmonary endothelium. These data indicate that temporal mechanisms modulate the inflammatory response due to i-I/R. Mediators in the lymph and circulation participate in the initiation / maintenance of lung inflammation by altering the integrity of the endothelium and activating the lung which release additional mediators.

No description available.

No description available.

Introduction: The use of high frequency oscillatory ventilation is increasing in treatment ofacute respiratory distress syndrome over the past decade. The technique of HFOV of ventilatingthe lungs at volumes less than the anatomical dead space calms the clinical concerns surroundingventilating stiff ARDS lungs with high pressures and volumes. This largely reduces theprobability of barotraumas and/or atelectrauma. Purpose: The study was on an in vitro bench model that answered the following researchquestions: 1. The effect of three inline closed suction adapters on delivered tidal volume duringHFOV with varying lung compliance 2. The effect of varying compliance on the amplitudedelivered by HFOV; and 3. The effect of compliance on tidal volume delivered by HFOV. Method: An in vitro bench model using high fidelity breathing simulator (ASL 5000, IngMarMedical) simulating an adult patient with ARDS was set up with 3100B SensorMedic highfrequency ventilator. The simulation included varying the compliance for each lung at 50, 40, 30and 20cmH2O while maintaining fixed resistance of 15 cmH2O/L/sec. The ventilator was set tothe following parameters: power of 6, frequency (f) of 5, inspiratory time (Ti) of 33%, bias flow(BF) of 30 LPM and oxygen concentration of 50%. The breathing simulator was connected withthe high frequency ventilator using a standard HFOV circuit and a size 8.0mm of endotrachealtube. Fourteen French Kimberly Clark suction catheters (with T and Elbow adapters) and Air-Life suction catheters (Y adapter) were placed in-line with the circuit successively to carry outthe study. Each run lasted for 1 minute after achieving stable state conditions. Thisapproximated to 300 breaths. The data was collected from the stimulator and stored by the hostcomputer. Data Analysis: The data was analyzed using SPSS v.11 to determine the statistical significance.A probability value (P value) of ≤ 0.001 was considered to be statistically significant. Results: The data analysis showed that Air-Life Y-adapter suction catheters caused the least lostin tidal volume when placed in line with HFOV and hence proved to be the most efficient. Thestudy also showed a direct relationship between amplitude and lung compliance i.e. an increasein lung compliance caused an associated increase in amplitude (power setting remainingunaltered). Lastly, the study did not show a statistically significant change in tidal volume withchanges in lung compliance. Future studies may be required to further evaluate the clinicalsignificance of the same. Conclusion:1. Many factors affect delivery of tidal volume during high frequency ventilation and thus it isnot constant. Choice of in-line suction system to be placed in line is one of the determinants ofthe same.2. Lung compliance changes lead to associated changes in amplitude delivery by HFOV. Thisshould be adjusted as patient condition improves by altering the power settings to ensure optimalventilation and to avoid trauma to the lungs.

Background: Our innate immunesystem protects us from infections but, since its methods is not all specific for microorganisms, may also induce collateral damage. Severe physical injury often proved deadly throughout evolution. Such injuries may induce massive collateral damage. Nowadays we can initiate advanced critical care for affected patients and save them from imminent trauma-related death. We are therefore faced with the fact that the collateral damage from the immune system may pose a major threat to the patient, the pathophysiology of which is not amenable to direct medical treatment and which leaves us with only passive supportive measures. In this thesis we investigated the role of leucocytes under such circumstances. Our main aim was to understand better the role of leucocytes in the development of increased vascular permeability after burns and trauma. More specifically we investigated the impact of an injury on the function of leucocytes such as the dynamic change of certain cell-surface receptors on the leucocytes and in their numbers and immature forms. We wanted to find out if the increased pulmonary vascular permeability after a burn could be mediated through heparin binding protein (HBP) released from granuloctes, and whether HBP could be used as a biomarker for respiratory failure after trauma. We also wanted to confirm the possible role of histamine as a mediator of the systemic increase in vascular permeability after burns. Methods: The dynamic change of cell-surface receptors was measured by flow-acquired cytometer scanning (FACS) on blood samples taken after burns. The concentrations of HBP after a burn and mechanical trauma were analysed in plasma. Pulmonary vascular permeability after a burn was assessed using transpulmonary thermodilution. The histamine turnover after a burn was assessed with high performance liquid chromatography (HPLC) for concentrations of histamine and methylhistamine in urine. Results: We confirmed earlier investigations showing altered expression of receptors on leucocytes after a burn, receptors intimately associated with leucocyte functions (study I). In a pilot study of 10 patients we measured plasma concentrations of HBP and found them to be increased soon after a burn (study II). This finding was not confirmed in a larger, more extensive and specific study of 20 patients. We did, however, find an association between alterations in the number of leucocytes soon after a burn and pulmonary vascular permeability, indicating that they had a role in this process (study III). In another study of trauma (non burn) we found an association between the concentration of HBP in early plasma-samples after injury and the development of ARDS, indicating that granulocytes and HBP have a role in its aetiology (study IV). We found a small increase in urinary histamine and normal urinary methylhistamine concentrations but had anticipated a distinct increase followed by a decrease after reading the current papers on the subject. This indicates that the role of histamine as a mediator of increased vascular permeability after burns may have been exaggerated (study V). Conclusions: We conclude that leucocytes are affected by burns and trauma, and it is likely that they contribute to the development of respiratory failure and acute respiratory distress syndrome (ARDS). HBP is a candidate biomarker for the early detection of ARDS after trauma, and the white blood count (WBC) is a useful biomarker for the detection of decreased oxygenation soon after a burn.