Tesis sobre el tema "Non invasive positive pressure ventilation"

The use of noninvasive positive pressure ventilation (NPPV) in acute care settings has drastically increased within the past 20 years. Research has indicated that NPPV is equally as effective as traditional mechanical ventilation(MV) in treating acute exacerbations of chronic pulmonary obstructive disease (COPD) and cardiogenic pulmonary edema. Furthermore, the risk of complication from NPPV is much lower than MV, in terms of ventilator-associated pneumonia and sepsis. It is imperative for the nurse to understand the various indications, interfaces, and potential complications associated with NPPV use. In addition to treating acute exacerbations of COPD and cardiogenic pulmonary edema, NPPV has been used for prevention of reintubation, palliative care, and status asthmaticus. Furthermore, NPPV could be delivered through various interfaces, such as nasal, facial, and helmet. Each of these interfaces could eventually cause complications for the patient, such as skin ulceration and sepsis. However, there is limited amount of research available discussing the role of the nurse in caring for the patient with NPPV. There are no standardized guidelines established to assist the nurse in this care, in terms of interface selection, prevention of complications, and staffing patterns. Several recommendations are presented at the end of this thesis to guide future nursing research, education, and clinical practice, such as exploring the role of oral care and education for NPPV patients.
B.S.N.
Bachelors
Nursing
Nursing

Résumé : Introduction : La ventilation nasale, de plus en plus utilisée chez le nourrisson, peut insuffler de l’air dans l’estomac et causer des reflux gastro-œsophagiens (RGO). Parmi les modes de ventilation nasale, l’aide inspiratoire (AIn) devrait entrainer un plus grand nombre de RGO que le neuro-asservissement de la ventilation assistée (NAVAn), où l’insufflation d’air est plus «physiologique». L’objectif principal de l’étude est de comparer le nombre de RGO en NAVAn et en AIn dans notre modèle ovin d’étude du RGO néonatal et de ventilation nasale. Méthodes : Une polysomnographie avec pH-impédancemétrie œsophagienne de 6 h a été effectuée chez 10 agneaux nouveau-nés. L’enregistrement a été répété trois jours consécutifs (une condition par jour) en respiration spontanée, AIn (15/4 cmH[indice inférieur 2]O) et NAVAn (15/4 cmH[indice inférieur 2]O) dans un ordre randomisé. Résultats : Comparé à la respiration spontanée [13 (23)], le nombre de RGO en 6 h a diminué fortement et de façon similaire en AIn [1 (3)] et en NAVAn [2 (2)] (p < 0,05), même pour des RGO faiblement acides et proximaux. De plus, le nombre d’insufflations d’air n’était pas différent entre l’AIn et la NAVAn. Conclusion : L’AIn et la NAVAn inhibent de façon équivalente les RGO chez l’agneau, incluant les RGO faiblement acides et proximaux, si la pression inspiratoire n’est pas trop élevée et malgré le fait que de l’air soit insufflé dans l’œsophage. Ce résultat est identique à celui obtenu avec l’application d’une pression positive continue nasale (6 cmH[indice inférieur 2]O). Il est possible que la pression positive appliquée lors de la ventilation diminue les relaxations transitoires du sphincter inférieur de l’œsophage, mais des études en manométrie œsophagienne sont nécessaires pour comprendre les mécanismes en jeu. // Abstract : Introduction: Nasal ventilation, increasingly used in infants, can blow air in the stomach and cause gastroesophageal reflux (GER). Among the nasal ventilation modes, pressure support ventilation (nPSV) should lead to a greater number of GER than neurally-adjusted ventilatory assist (nNAVA), where the air delivery is more "physiological". The main objective of the study is to compare the number of GER in nNAVA and nPSV in our unique sheep model of neonatal GER and nasal ventilation. Methods: A 6h polysomnographic recording with esophageal pH-impedance was performed in 10 newborn lambs. The recording was repeated for three consecutive days (one condition per day) for spontaneous breathing, nPSV (15/4 cmH[subscript 2]O) and nNAVA (15/4 cm H[subscript 2]O) in a randomized order. Results: Compared with spontaneous breathing [13 (23)], the number of GER in 6h strongly and similarly decreased in nPSV [1 (3)] and nNAVA [2 (2)] (p < 0.05), even proximal and weakly acidic GER. In addition, the number of air insufflations was not different between nPSV and nNAVA. Conclusion: nPSV and nNAVA both inhibit GER in lambs, including weakly acidic and proximal GER, if the inspiratory pressure is not too high and despite the fact that air is blown into the esophagus. This result is identical to the one obtained with the application of a nasal continuous positive airway pressure (6 cmH[subscript 2]O). It is posssible that the applied positive pressure decreases transient relaxations of the lower esophageal sphincter, but esophageal manometry studies are needed to understand the mechanisms involved.

Doctor of Philosphy (PhD)
This thesis describes the work carried out during four treks, each over 10-11 days, from 1400m to 5000m in the Nepal Himalaya and further work performed during several two-night sojourns at the Barcroft Laboratory at 3800m on White Mountain in California, USA. Nineteen volunteers were studied during the treks in Nepal and seven volunteers were studied at White Mountain. All subjects were normal, healthy individuals who had not travelled to altitudes higher than 1000m in the previous twelve months. The aims of this research were to examine the effects on sleep, and the ventilatory patterns during sleep, of incremental increases in altitude by employing portable polysomnography to measure and record physiological signals. A further aim of this research was to examine the relationship between the ventilatory responses to hypoxia and hypercapnia, measured at sea level, and the development of periodic breathing during sleep at high altitude. In the final part of this thesis the possibility of preventing and treating Acute Mountain Sickness with non-invasive positive pressure ventilation while sleeping at high altitude was tested. Chapter 1 describes the background information on sleep, and breathing during sleep, at high altitudes. Most of these studies were performed in hypobaric chambers to simulate various high altitudes. One study measured sleep at high altitude after trekking, but there are no studies which systematically measure sleep and breathing throughout the whole trek. Breathing during sleep at high altitude and the physiological elements of the control of breathing (under normal/sea level conditions and under the hypobaric, hypoxic conditions present at high altitude) are described in this Chapter. The occurrence of Acute Mountain Sickness (AMS) in subjects who travel form near sea level to altitudes above 3000m is common but its pathophysiology not well understood. The background research into AMS and its treatment and prevention are also covered in Chapter 1. Chapter 2 describes the equipment and methods used in this research, including the polysomnographic equipment used to record sleep and breathing at sea level and the high altitude locations, the portable blood gas analyser used in Nepal and the equipment and methodology used to measure each individual’s ventilatory response to hypoxia and hypercapnia at sea level before ascent to the high altitude locations. Chapter 3 reports the findings on the changes to sleep at high altitude, with particular focus on changes in the amounts of total sleep, the duration of each sleep stage and its percentage of total sleep, and the number and causes of arousals from sleep that occurred during sleep at increasing altitudes. The lightest stage of sleep, Stage 1 non-rapid eye movement (NREM) sleep, was increased, as expected with increases in altitude, while the deeper stages of sleep (Stages 3 and 4 NREM sleep, also called slow wave sleep), were decreased. The increase in Stage 1 NREM in this research is in agreement with all previous findings. However, slow wave sleep, although decreased, was present in most of our subjects at all altitudes in Nepal; this finding is in contrast to most previous work, which has found a very marked reduction, even absence, of slow wave sleep at high altitude. Surprisingly, unlike experimental animal studies of chronic hypoxia, REM sleep was well maintained at all altitudes. Stage 2 NREM and REM sleep, total sleep time, sleep efficiency and spontaneous arousals were maintained at near sea level values. The total arousal index was increased with increasing altitude and this was due to the increasing severity of periodic breathing as altitude increased. An interesting finding of this research was that fewer than half the periodic breathing apneas and hypopneas resulted in arousal from sleep. There was a minor degree of upper airway obstruction in some subjects at sea level but this was almost resolved by 3500m. Chapter 4 reports the findings on the effects on breathing during sleep of the progressive increase of altitude, in particular the occurrence of periodic breathing. This Chapter also reports the results of changes to arterial blood gases as subjects ascended to higher altitudes. As expected, arterial blood gases were markedly altered at even the lowest altitude in Nepal (1400m) and this change became more pronounced at each new, higher altitude. Most subjects developed periodic breathing at high altitude but there was a wide variability between subjects as well as variability in the degree of periodic breathing that individual subjects developed at different altitudes. Some subjects developed periodic breathing at even the lowest altitude and this increased with increasing altitude; other subjects developed periodic breathing at one or two altitudes, while four subjects did not develop periodic breathing at any altitude. Ventilatory responses to hypoxia and hypercapnia, measured at sea level before departure to high altitude, was not significantly related to the development of periodic breathing when the group was analysed as a whole. However, when the subjects were grouped according to the steepness of their ventilatory response slopes, there was a pattern of higher amounts of periodic breathing in subjects with steeper ventilatory responses. Chapter 5 reports the findings of an experimental study carried out in the University of California, San Diego, Barcroft Laboratory on White Mountain in California. Seven subjects drove from sea level to 3800m in one day and stayed at this altitude for two nights. On one of the nights the subjects slept using a non-invasive positive pressure device via a face mask and this was found to significantly improve the sleeping oxyhemoglobin saturation. The use of the device was also found to eliminate the symptoms of Acute Mountain Sickness, as measured by the Lake Louise scoring system. This finding appears to confirm the hypothesis that lower oxygen saturation, particularly during sleep, is strongly correlated to the development of Acute Mountain Sickness and may represent a new treatment and prevention strategy for this very common high altitude disorder.

L’insuffisance respiratoire chronique est un syndrome défini par une défaillance monoviscéralerespiratoire. Sa principale origine est aujourd’hui le syndrome obésité-hypoventilation qui concerne 4 à 5% des patients obèses. L’IRC est aussi le stade évolutif terminal de la bronchopneumopathie chronique obstructive qui touche 6 à 8% de la population adulte. L’incidence de ces pathologies et donc de l’insuffisance respiratoire est en augmentation constante. Dans cette thèse, nous avons évalué les nouvelles modalités diagnostiques et thérapeutiques qui pourraient améliorer la prise en charge des patients atteints d’insuffisance respiratoire chronique.Concernant la prise en charge diagnostique, nous avons montré que les données fournies par l’électromyographie de surface des muscles intercostaux, outil qui évalue le travail respiratoire, constituent un marqueur pronostique indépendant chez les patients atteints de bronchopneumopathie chronique obstructive. Nous avons également montré leur pertinence pour prédire l’efficacité clinique et l’observance à la ventilation non-invasive à domicile.Concernant la prise en charge thérapeutique, nous avons montré que l’utilisation d’un mode semi-automatisé de ventilation non-invasive a la même efficacité que celle de modes classiques en permettant une mise en place plus rapide du traitement. Nous avons également rapporté l’intérêt de l’oxygénothérapie à haut débit au domicile alors que ce traitement était utilisé jusque-là dans le seul cadre des soins intensifs. Enfin, nous avons rapporté les bénéfices de la pression positive continue au cours de l’effort chez les patients ayant une trachéobronchomalacie. Concernant le suivi des patients, nous avons montré que les données des logiciels de ventilation non invasive permettent de prédire la survenue d’une exacerbation sévère de BPCO mais que l’utilisation de la télémédecine chez les patients insuffisants respiratoires chroniques ne peut être encore pleinement intégrée dans la pratique clinique. Au cours de cette thèse, nous avons identifié de nouveaux outils physiologiques, de nouvelles modalités d’administration des traitements et de nouveaux outils de suivi à domicile, à même d’améliorer la prise en charge des patients insuffisants respiratoires chroniques
Single-organ respiratory failure defines chronic respiratory failure. Obesity hypoventilation syndrome is the main cause of chronic respiratory failure and occurs in 4 to 5% of obese patients. Chronic respiratory failure is also the end-stage evolution of chronic obstructive pulmonary disease that has a prevalence of 6 to 8% in the adult population. The incidence of these diseases increases so does the incidence of chronic respiratory failure. In this thesis, we will evaluate novel diagnostic and therapeutic modalities that could improve the care of patients with chronic respiratory failure. Regarding diagnostic modalities, we have seen that evaluating the work of breathing with surface parasternal electromyography was an independent prognostic marker in patients with chronic obstructive pulmonary disease. We have also seen that it was a relevant tool to predict the clinicalefficacy and compliance to home non-invasive ventilation. Regarding therapeutic modalities, we have shown that the use of a semi-automatic mode of non-invasive ventilation had the same efficacy of a standard mode with a shorter length of stay for its setup. We have shown the relevance and feasibility of the use of high-flow oxygen therapy in the home setting whilst it was only used in intensive care units. Finally, we have shown the benefits of continuous positive airway pressure during exertion in patients with tracheobronchomalacia. Regarding patients’ follow-up, we have shown that the use of data from built-in software could predict the onset of a severe exacerbation of chronic obstructive pulmonary disease. However, we also show that the implementation of tele-medicine in patients with chronic respiratory failure cannot be included in daily clinical practice yet. In this thesis, we have identified novel physiological tools, novel ways to administer treatments and novel follow-up tools that can improve the management of patients with chronic respiratory failure

INTRODUÇÃO: A síndrome da imunodeficiência adquirida (AIDS) é atualmente uma pandemia, e as doenças pulmonares são a principal causa de morbidade e mortalidade dos pacientes com AIDS. Nesse sentido, as infecções respiratórias são frequente causa de hipoxemia e morte. Os pacientes com AIDS e insuficiência respiratória hipoxêmica frequentemente necessitam de ventilação mecânica invasiva, a qual é independentemente associada com mortalidade. A ventilação não invasiva com pressão positiva refere-se à oferta de assistência ventilatória mecânica sem a necessidade de invasão artificial das vias aéreas, sendo reconhecida por melhorar a oxigenação e a dispneia dos pacientes com insuficiência respiratória hipoxêmica, principalmente se aplicada de forma sequencial e progressiva, e esta pode reduzir a necessidade de ventilação mecânica invasiva nestes pacientes. Tendo em vista as incertezas quanto à resposta da oxigenação a PEEP nos pacientes com AIDS com insuficiência respiratória aguda hipoxêmica e usando o racional da pressurização progressiva das vias aéreas e seu potencial benefício na oxigenação sanguínea, nós fizemos a hipótese de que o incremento sequencial dos níveis de PEEP até 15 cmH2O pode melhorar a oxigenação sanguínea sem afetar o conforto e a hemodinâmica do paciente. O objetivo principal deste estudo foi investigar os efeitos de diferentes sequências de níveis de PEEP aplicado de forma não invasiva sobre as trocas gasosas, a sensação de dispneia e os padrões hemodinâmicos em pacientes com AIDS e insuficiência respiratória aguda hipoxêmica. O objetivo secundário foi avaliar o tempo livre de ventilação mecânica invasiva em 28 dias e a mortalidade hospitalar em 60 dias. MÉTODOS: Foram estudados 30 pacientes adultos com HIV/AIDS e insuficiência respiratória aguda hipoxêmica. Todos os pacientes receberam uma sequência randomizada de PEEP não invasivo (os valores usados foram 5, 10 ou 15 cmH2O) por vinte minutos. A PEEP foi fornecida através de máscara facial com pressão suporte (PSV) de 5 cmH2O e uma FiO2 = 1. Um período de washout de 20 minutos com respiração espontânea foi permitido entre cada PEEP. Variáveis clínicas e uma gasometria arterial foram registradas após cada etapa de PEEP. RESULTADOS: Analisando os 30 pacientes, a oxigenação melhorou linearmente com a elevação da PEEP, contudo, estudando os pacientes conforme a PEEP inicial randomizada, a oxigenação foi similar independentemente da primeira PEEP randomizada (5, 10 ou 15 cmH2O), e somente o subgrupo com PEEP inicial = 5 cmH2O melhorou mais a oxigenação quando PEEPs maiores foram usadas. A PaCO2 também aumentou junto com a elevação da PEEP, especialmente com uma PEEP = 15 cmH2O. O uso de PSV = 5 cmH2O foi associado com significante e consistente melhora da sensação subjetiva de dispnéia e da frequência respiratória com PEEP de 0 a 15 cmH2O. CONCLUSÕES: Os pacientes com SIDA e insuficiência respiratória hipoxêmica melhoram a oxigenação com a elevação progressiva e sequencial da PEEP até 15 cmH2O, contudo a elevação da PaCO2 limita a PEEP até 10 cmH2O. Uma PSV = 5 cmH2O promove uma melhora da sensação subjetiva da dispnéia independentemente do uso de PEEP
INTRODUTION: The acquired immunodeficiency syndrome (AIDS) is a pandemic, and lung diseases are the leading cause of morbidity and mortality and are often associated with respiratory infections, hypoxemia and death. The noninvasive ventilation with positive pressure refers to the provision of mechanical ventilatory assistance without the need for artificial airway invasion, being recognized for improving oxygenation and dyspnea in patients with hipoxemic respiratory failure. Patients with AIDS and hypoxemic respiratory failure often require invasive mechanical ventilation, which is independently associated with mortality. Given the uncertainties about response in oxygenation with PEEP in patients with AIDS with acute hypoxemic respiratory failure and using the rational for progressive pressurization of the airway and its potential benefits on blood oxygenation, we made the hypothesis that increased levels of sequential PEEP up to 15 cmH2O may improve blood oxygenation without affecting the comfort and hemodynamics of the patient. The main objective of this study was to investigate the effects of different sequences of PEEP levels on gas exchange, the sensation of dyspnea and hemodynamics in patients with AIDS and acute hypoxemic respiratory failure. The secondary objective was to assess the time free of invasive mechanical ventilation in 28 days and hospital mortality within 60 days. METHODS: We studied 30 adults patients with HIV/AIDS and acute hypoxemic respiratory failure. All patients received a randomized sequence of noninvasive PEEP (the values used were 5,10 or 15 cmH2O) for twenty minutes. PEEP was delivered via face mask with pressure support (PSV) of 5 cmH2O and FiO2 = 1. A washout period of 20 minutes with spontaneous breathing was allowed between each PEEP trial. Clinical variables and arterial blood gases were recorded after each PEEP step. RESULTS: Analyzing the 30 patients, oxygenation improved linearly with increasing PEEP, however studying the patients randomized according to the initial PEEP, oxygenation was similar regardless of the first randomized PEEP (5,10 or 15 cmH2O), and only the subgroup with initial PEEP = 5 cmH2O further improve the oxygenation when high PEEP were used. The PaCO2 also rose beside the PEEP elevation, especially with a PEEP = 15 cmH2O. The use of PSV = 5 cmH2O was associated with significant and consistent improvement of subjective sensation of dyspnea and respiratory rate with a PEEP from 0 to 15 cmH2O. CONCLUSION: AIDS-patients with hypoxemic respiratory failure improve oxygenation with a progressive sequential elevation of PEEP up to 15 cmH2O, however the elevation of PaCO2 limit the PEEP up to 10 cmH2O. A PSV = 5 cmH2O promotes an improvement of subjective sensation of dyspnea independently from the use of PEEP

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Universidade Federal de Sao Carlos
The changes on the heart rate sympathetic-vagal balance caused to chronic obstructive pulmonary disease or chronic heart failure, as well as, the hemodynamics change induced by the non-invasive ventilation were unclear. In this context, we proposed to develop two studies. The first study was titled by The heart rate autonomic control in chronic obstructive pulmonary disease and chronic heart failure patients on the rest and during the respiratory sinusal arrhythmia maneuver . The purpose of this study was to evaluate the heart rate (HR) autonomic modulation in chronic obstructive pulmonary disease (COPD) patients as well as chronic heart failure (CHF) patients on the rest as well as during the respiratory sinus arrhythmia maneuver (M-RSA); and to correlation the HR autonomic modulation and seriousness levels of both pathologies. Twenty-seven male volunteers were subdivided in three groups: ten presented COPD (69±9 years); seven presented CHF (62±8 years) and; ten were healthy with 64±5 year-old (control). When resting, the three groups electrocardiography signal was obtained in three conditions: 1) lying position for 15 min; 2) lying position during the M-RSA for 4 min; and 3) sitting position for 15 min. The data was analyzed by the time (RMSSD and SDNN indexes) and the frequency domain, in total power, low frequency, high frequency absolute (ab) and normalized (nu) units and LF/HF ratio. Regarding the M-RSA indexes, the expiratory/inspiratory ratio (E/I) and the inspiratory/expiratory difference (∆IE) were calculated. The main results showed that the CHF and the COPD patients presented lower E/I ratio values (0,03±0,01 vs 0,09±0,04 e 0,04±0,02 vs 0,09±0,04) and ∆I/E values (0,67±0,13 vs 1,09±0,13 e 0,81±0,20 vs 1,09±0,13), when compared to control group. Strong correlations were observed between the forced expiratory volume in the first second (FEV1) and the RMSSD (r=-0,73) and between the FEV1 and the BF absolute (r=-0,71) in the COPD patients. At same, strong correlations were observed between the ejecting fraction and the RMSSD (r=0,83) in CHF patients. Concluding, the results of this study suggest that both, the COPD and the CHF patients, presented parasympathetic activity reduction and there is a relation between the seriousness levels of both pathologies and the HR autonomic activity. The second study was titled to The acute effects of the continuous positive airway pressure (CPAP) in the heart rate autonomic control of chronic obstructive pulmonary disease and chronic heart failure patients . The purpose of this study was to evaluate the acute continuous positive pressure airway over the heart rate (HR) autonomic control and the respiratory variables behavior in COPD as well as CHF patients. Twenty-eight male volunteers were sub-divided in three groups: ten presented COPD (69±9 years); eight presented CHF (62±8 years) and; ten were healthy with 64±5 year-old (control). The electrocardiography signal was obtained for 10 min in the sitting position with spontaneous breath (SB) and following randomly conditions: CPAP Sham, CPAP 5, and CPAP 10 cmH2O. Additionally, the breath rate, the endtidal of carbon dioxide, and the peripheral oxygen saturation were obtained. The HR and it variability data were analyzed by the time and the frequency domain, in according with previous describe. The main results showed that the ETCO2 reduced in all groups during the CPAP application. COPD group were significantly lower values of the RMSSD index in the Sham (1.06), CPAP 5 (1.08), and CPAP 10 (1,01) than SB (1,22). In addition, they presented increased in the LFnu (1.60 vs 1.82) and decreased in the HFab (1.90 vs 1.55) from the SB to CPAP 10. The CHF group RMSSD index and TP increased to SB (1.31 and 2.62) to CPAP 5 (1.44 and 2.87) and the CPAP 10 (1.48 and 2.97), respectively. Concluding, the CPAP caused modification in the HR autonomic control and improvement in the alveolar ventilation of COPD, CHF patients and healthy individuals.
As modificações do balanço simpato-vagal da freqüência cardíaca (FC) provocadas com o curso da doença pulmonar obstrutiva crônica (DPOC) e da insuficiência cardíaca crônica (ICC), bem como, as que ocorrem em função dos ajustes hemodinâmicos induzidos pela aplicação da ventilação não invasiva são bastante contraditórias. Neste contexto, propusemos o desenvolvimento de dois estudos que poderiam contribuir com novas informações. O primeiro intitulado por Controle autonômico da freqüência cardíaca de pacientes com doença pulmonar obstrutiva crônica ou insuficiência cardíaca crônica em repouso e durante a manobra de acentuação arritmia sinusal respiratória teve por objetivos avaliar o controle autonômico da FC de pacientes com DPOC ou ICC em repouso e durante uma manobra de acentuação da arritmia sinusal respiratória (M-ASR), bem como, relacionar a atividade autonômica da FC com a gravidade das patologias. Vinte e sete voluntários do sexo masculino foram subdivididos em três grupos: 10 com DPOC (GD) e 69±9 anos; 7 com ICC (GI) e 62±8 anos; e 10 saudáveis (GC) com 64±5 anos. Em repouso, o sinal eletrocardiográfico foi obtido em três situações: 1) 15 min na posição supina; 2) 4 min durante M-ASR na posição supina; e 3) 15 min na posição sentada. Os dados foram analisados no domínio do tempo (índices RMSSD e SDNN) e da freqüência, pela densidade espectral total (DET), bandas de baixa (BF) e alta freqüências (AF) - absolutas (ab) e normalizadas (un), e a razão BF/AF. Durante M-ASR foram calculadas a razão expiração/inspiração (E/I) e a diferença inspiração/expiração (∆IE). Os principais resultados em logaritmos decimais (média±desvio-padrão) mostraram que os pacientes com ICC e DPOC apresentaram menor razão E/I (0,03±0,01 vs 0,09±0,04 e 0,04±0,02 vs 0,09±0,04) e ∆IE (0,67±0,13 vs 1,09±0,13 e 0,81±0,20 vs 1,09±0,13), respectivamente, comparados ao GC durante a M-ASR. Correlações fortes foram observadas entre volume expiratório forçado no primeiro segundo com o RMSSD (r=-0,73) e com a BF absoluta (r=-0,71) nos pacientes com DPOC; e entre fração de ejeção e o RMSSD (r=0,83) nos pacientes com ICC. Em conclusão, os resultados sugerem que tanto a DPOC como a ICC levam a redução da atividade parassimpática e que a gravidade de ambas está relacionada com o controle autonômico da FC. O segundo estudo com o titulo: Efeitos da aplicação aguda da pressão positiva continua nas vias aéreas sobre o controle autonômico da freqüência cardíaca de pacientes com doença pulmonar obstrutiva crônica ou insuficiência cardíaca crônica , objetivou avaliar o efeito agudo da pressão positiva continua nas vias aéreas (CPAP) sobre o controle autonômico da freqüência cardíaca (FC) e o comportamento de variáveis respiratórias de pacientes com DPOC ou ICC. 28 homens foram subdivididos em três grupos: 10 com DPOC (GD) e 69±9 anos; 8 com ICC (GI) e 62±8 anos; e 10 saudáveis (GC) com 64±5 anos. O sinal eletrocardiográfico foi obtido por 10 min na posição sentada com respiração espontânea (RE) e randomicamente nas condições: CPAP sham, CPAP 5 e CPAP 10 cmH2O. Adicionalmente, foram obtidos os valores da freqüência respiratória, o volume de dióxido de carbono no final da expiração (ETCO2) e a saturação periférica de oxigênio. A FC e sua variabilidade foram analisadas no domínio do tempo e da freqüência, conforme descrito anteriormente. Os principais resultados mostraram que o ETCO2 reduziu em todos os grupos durante a aplicação da CPAP. O GD apresentou menores valores do RMSSD durante a CPAP sham (1,06), 5 (1,08) e 10 (1,01) em comparação a RE (1,22), bem como, aumento da BFun (1,60 vs 1,82) e redução da AFab (1,90 vs 1,55) da RE para a CPAP 10. No GI, o SDNN e a DET aumentaram da condição de RE (1,31 e 2,62) para CPAP 5 (1,44 e 2,87) e 10 (1.48 e 2,97), respectivamente. Os resultados sugerem que a CPAP melhorou a ventilação alveolar e provocou atenuação da atividade simpática sobre a FC de pacientes com ICC, bem como redução do tônus vagal de pacientes com DPOC.

Bakgrund: Patienter med kronisk obstruktiv sjukdom (KOL) som behandlas med Non-invasiv ventilation (NIV) har risk för trycksår och malnutrition. Observation och övervakning av patienterna är viktigt för att kunna följa behandlingsförloppet och tidigt upptäcka en eventuell försämring samt förebygga komplikationer. Dokumentation av given omvårdnad måste kunna följas för att utvärdera och säkerställa kraven på en god och säker vård. Syfte: Syftet med studien var att granska omvårdnadsdokumentationen för patienter med KOL som behandlats med NIV på en medicinsk akutvårdsavdelning. Metod: Studien genomfördes som en retrospektiv systematisk journalgranskning i 75 journaler med en granskningsmall. Resultat: Omvårdnadsprocessens steg fanns inte dokumenterad i sin fullständighet för trycksår eller nutrition i någon journal. Dokumentationen av omvårdnadsprocessen för trycksår var oberoende av antal vårddygn, kön och ålder men beroende av antal dygn med NIV.  För nutrition var dokumentationen av omvårdnadsprocessen beroende av antal NIV- och vårddygn men oberoende av kön och ålder. Dokumentationen för omvårdnad och behandling med NIV var utspridd i journalen under olika rubriker. Slutsats: Studiens resultat visade att det fanns brister i omvårdnadsdokumentationen.

Nasal continuous positive airway pressure (CPAP) is reportedly superior to mechanical ventilation in the neonatal population by reducing bronchopulmonary dysplasia (BPD). The neonate is vulnerable to injury secondary to immature physiological systems and skin structures and the current CPAP devices place constant pressure on nares, nasal septum and forehead, increasing injury risk. Through the framework of comparative effectiveness research an examination of nasal interfaces currently used during neonatal CPAP was conducted in an effort to provide scientifically supported recommendations and improve clinical outcomes. The primary aim of this study was to determine differences in the frequency, severity and specific types of nasal injuries described when comparing different nasal CPAP interfaces (prongs/mask/rotation) used in the treatment of neonatal respiratory distress syndrome (RDS). A secondary aim of the study was to identify risk factors that may be associated with skin breakdown during nasal CPAP administration. A three group prospective randomized experimental design was used to study78 neonates <1500 grams receiving nasal CPAP using the same delivery system. The subjects were randomized into three groups: 1) continuous nasal prong group, 2) continuous nasal mask group, or 3) alternating mask/prongs group. Serial data collection included: demographic, biophysical measures and the Neonatal Skin Condition Scale (NSCS). This study demonstrated a significant difference in the frequency and severity of skin injury when utilizing a method of rotating mask and prong nasal interfaces during neonatal CPAP therapy; a useful clinical recommendation. Specific nursing care implications related to study findings include; choosing a device for best fit for infant (face shape and infant size); positioning of the CPAP device; developmental position of the infant; and focused skin assessment with rapid intervention. Standardized care including skin barriers, clinical expertise of nursing and respiratory therapy, and skin care management are strategies that warrant additional research.

Au cours du traitement du syndrome d’apnées obstructives du sommeil (SAOS) par pression positive continue (PPC), les fuites non-intentionnelles sont un des effets indésirables les plus fréquents mais leur étiologie est mal comprise. Les objectifs de cette thèse étaient d’identifier les facteurs déterminants des fuites non-intentionnelles au cours du traitement du SAOS par PPC et de proposer des stratégies pour le choix du masque et la gestion des fuites.Dans notre revue de la littérature, nous avons arbitrairement classifié les déterminants potentiels à l’origine de fuites non-intentionnelles en deux catégories. 1) les déterminants non évolutifs au cours de la nuit : l’obstruction nasale, l’âge, un indice de masse corporel élevé, une distribution centrale des masses adipeuses et le genre masculin étaient des déterminants potentiels des fuites non-intentionnelles. Le masque naso-buccal était également associé à des fuites non-intentionnelles plus élevées que le masque nasal ; et 2) les déterminants évolutifs au cours du sommeil tels que les stades de sommeil, la position, l’ouverture buccale. Nous avons étudié ces déterminants évolutifs dans une population de 74 patients SAOS traités par PPC auto-pilotée : l’ouverture buccale, le niveau de pression de la PPC, la position du sujet et le sommeil paradoxal contribuaient au risque de fuite non-intentionnelle. Nous avons également mis en évidence que le masque naso-buccal réduisait le risque de fuite non-intentionnelle en cas d’ouverture buccale et au cours du sommeil paradoxal. Puisque le niveau de pression est un déterminant des fuites non-intentionnelles, nous avons évalué par une analyse ancillaire d’un essai randomisé contrôlé, si le mode de PPC (fixe versus autopiloté) pouvait contribuer aux fuites : nous n’avons pas montré d’association entre le mode et le niveau de fuites après 4 mois de traitement. Le mode PPC n’influençait pas le type de masque utilisé par les patients. Enfin, au cours d’une étude prospective incluant de 214 patients, nous avons évalué l’intérêt du questionnaire Nasal Obstruction Syndrom Evaluation (NOSE) comme outil pour guider le choix du masque. Un score NOSE > 50/100 à l’initiation de la PPC était indépendamment associé à l’utilisation d’un masque naso-buccal après 4 mois de traitement. Ce score est un outil simple pour évaluer objectivement les symptômes d’obstruction nasale et faciliter le choix de l’interface la plus appropriée. En conclusion, au cours de cette thèse nous avons développé une méthode innovante d’analyse des déterminants des fuites non-intentionnelles dont l’application clinique pourrait permettre la mise en place des stratégies de corrections individualisées des fuites. Cela devra faire l’objet d’une évaluation prospective, tout comme l’intérêt clinique de l’utilisation en routine du score NOSE pour guide le choix du masque.Mots clés : syndrome d’apnées obstructives du sommeil, pression positive continue, fuites, masque, interface, obstruction nasale, sommeil
Continuous Positive Airway Pressure (CPAP) is the first-line treatment for moderate to severe Obstructive Sleep Apnea (OSA) syndrome. Unintentional leakage and its annoying consequences are the most frequently reported adverse effects. However, the causes of unintentional leaks are poorly understood. This thesis aimed at identifying the determining factors of unintentional leaks during CPAP treatment in OSA and developping innovative strategies for the selection of masks and leaks management.In our systematic review we have arbitrarily split the potential determining factors of leaks into two categories: 1) the non evolving factors overnight: nasal obstruction, age, high body mass index, central fat distribution and male sex were potential contributing factors associated with unintentional leakage. The oronasal mask was associated with higher unintentional leaks than the nasal mask; and 2) the evolving factors overnight such as sleep stages, body position, mouth opening and CPAP level. We studied these evolving factors in 74 OSA patients treated with auto-adjusting CPAP: mouth opening, CPAP level, body position and REM sleep were independently associated with an increased risk of unintentional leakage. We also highlighted that oronasal masks reduced the risk of unintentional leaks in cases of mouth opening and REM sleep. Since the CPAP level is a determining factor of leakage we evaluated through an ancillary analysis of a randomised controlled trial whether the type of CPAP (fixed versus auto-adjusting) could contribute to leakage. In this study, there was no effect of type of CPAP on leaks or the type of interface used after 4 month of treatment. Finally, in 214 patients, we prospectively evaluated the relevance of the Nasal Obstruction Syndrom Evaluation (NOSE) score as a simple decision-making tool to guide the choice of mask during CPAP initiation. A NOSE score > 50/100 at the initiation was independently associated with the use of an oronasal mask at 4 month. This score could be a simple tool for the objective assessment of nasal obstruction related to symptoms, facilitating the choice of an appropriate interface. As a conclusion, during this thesis we have developed a novel methodology to characterise and analyse the overnight determinants of unintentional leakage. Its clinical application could lead to individualised corrective measures of leaks. Further studies are needed to prospectively validate this model, as well as the clinical relevance of the NOSE score to guide the choice of mask in daily practice

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Non-invasive positive pressure ventilation (NPPV) provides respiratory support to patients without the need for invasive intubation. Although it has been used for several years in critical care, NPPV has come to prominence as a management option for certain patients with respiratory complications of coronavirus disease 2019 (COVID-19). This has led to increased care provision by nurses with little or no experience and expertise in critical care and NPPV. This article provides an overview of the principles of NPPV and its use in type 1 and type 2 respiratory failure. It explains the pathophysiology of several conditions that often lead to respiratory failure and how NPPV can mitigate respiratory failure and improve gas exchange. An individualised assessment of the patient’s suitability for NPPV and an evaluation of the effectiveness of the therapy are crucial to ensure its safe and effective use. Nurses also have an important role in providing explanations and support to patients.

碩士
中臺科技大學
健康產業管理研究所
99
Abstract Background: Patients of respiratory failure with endo trachea intubation emerged in an endless stream in the hospital. According to the literatures, re-intubation resulting from extubation failure would increase death risk, length of stay, medical expense, and nosocomial. Therefore, extubation success rate has become an important issue in quality of care. Objectives: This study aimed to identify the association between the successful-weaning of non-invasive positive pressure ventilation after extubation and related-quality indicators by analyzing the correlation of patient characteristics before extubation, weaning parameters and two different methods for respiratory care after extubation. The results would provide the direct that prompted quality of care and set up the standard process. Method: A retrospective study collected medical records data of patients who were respiratory failure after extubation in a regional teaching hospital in Taichung from January, 2009 to December, 2010. The study group was patients who used non-invasive positive pressure ventilation after extubation , those who used oxygen after extubation were defined in control group. 157 cases were qualified in this study finally. Statistical methods included descriptive statistics, Chi-square test, independent samples t-test, logistic regression, and multiple regression analysis. Results: Patients in study group were older, longer days of intubation and poor score of consciousness than the control group. There was no significant difference between two groups in the success of extubation, death, re-intubation, and pneumonia after controlling the patient characteristics and weaning parameters. However, the study group had longer length of stay in ICU after extubation and total length of stay after extubation than the control group. Conclusion: To reduce complications occurred in poor condition patient, those who are older, longer days of intubation and poor score of consciousness have more necessity to use the non-invasive positive pressure ventilation after extubation. Non-invasive positive pressure ventilation can be used for preventive purpose after extubation immediately. Keywords: respiratory failure, weaning index, non-invasive positive pressure ventilation, re-intubation

碩士
長榮大學
醫務管理學系碩士班
107
Background Noninvasive positive pressure ventilation has been widely used for the care of patients with acute respiratory failure in intensive care units as an alternative to endotracheal intubation. However, past studies that examined the predictors of successful use of this treatment had mostly used laboratory test results as predictors. Few studies have investigated whether some important ventilator parameters, such as respiratory rate, tidal volume, rapid shallow breathing index, lung compliance, and airway resistance, predict successful use of noninvasive positive pressure ventilation. This study will be one of the first in Taiwan to explore the predictors of successful use of noninvasive positive pressure ventilation within seventy-two hours after its use. Method 148 patients with acute respiratory failure treated in a regional hospital in southern Taiwan were included in this retrospective analysis. We collected data on the respiratory rate, tidal volume, rapid shallow breathing index, lung compliance, airway resistance, fraction of inspired oxygen (FiO2), and the Glasgow coma scale(GCS) at 0, 2, 4, 6, 12, 24, 48 hours after the start of noninvasive positive pressure ventilation. For each of the seven time-dependent covariates, we defined five time-varying covariates. Cox’s proportional hazards models were used for analysis. Result 75 patients (50.67%) successfully weaned from noninvasive positive pressure ventilation within 72 hours. Among the thirty-five time-dependent covariates, the following conditions significantly predict the success of the treatment: the slope of the airway resistance change was between -1.30 and 0.04 (HR=25.34), the change in FiO2 used was<10% (HR=12.03), mean value of lung compliance before the successful detachment was greater than 86.58 ml/cm H2O (HR=4.91), the average respiratory rate was between 26.86 ~ 40.66 breaths/min (HR=3.23), the value of lung compliance closest to successful detachment was between 40.38 and 105.77 ml/cm H2O (HR=3.04), the initial respirator-set oxygen concentration<38% (HR=2.34), the initial rapid shallow breathing index ranged from 81.57 to 146.61 breaths/min/L (HR=2.27), scores for the coma scale closest to the successful detachment was greater than 12.18 (HR=3.68). On the other hand, those with higher initial respiratory rate (HR=0.9) and those with higher respiratory rate closest to successful detachment (HR=0.8) were more likely to fail. Conclusions Noninvasive positive pressure ventilation is increasingly used in intensive care unit for the care of acute respiratory failure patients. In this study, we explored factors that can predict success of this treatment in a timely and non-invasive fashion, that is, using respiratory parameters to predict whether a patient will successfully wean from noninvasive positive pressure ventilation within 72 hours. This study provides several simple and objective indicators to help clinicians identify high-risk cases to avoid delaying intubation.

Introduction: La ventilation non invasive (VNI) est un outil utilisé en soins intensifs pédiatriques (SIP) pour soutenir la détresse respiratoire aigüe. Un échec survient dans près de 25% des cas et une mauvaise synchronisation patient-ventilateur est un des facteurs impliqués. Le mode de ventilation NAVA (neurally adjusted ventilatory assist) est asservi à la demande ventilatoire du patient. L’objectif de cette étude est d’évaluer la faisabilité et la tolérance des enfants à la VNI NAVA et l’impact de son usage sur la synchronie et la demande respiratoire. Méthode: Étude prospective, physiologique, croisée incluant 13 patients nécessitant une VNI dans les SIP de l’hôpital Ste-Justine entre octobre 2011 et mai 2013. Les patients ont été ventilés successivement en VNI conventionnelle (30 minutes), en VNI NAVA (60 minutes) et en VNI conventionnelle (30 minutes). L’activité électrique du diaphragme (AEdi) et la pression des voies aériennes supérieures ont été enregistrées pour évaluer la synchronie. Résultats: La VNI NAVA est faisable et bien tolérée chez tous les enfants. Un adolescent a demandé l’arrêt précoce de l’étude en raison d’anxiété reliée au masque sans fuite. Les délais inspiratoires et expiratoires étaient significativement plus courts en VNI NAVA comparativement aux périodes de VNI conventionnelle (p< 0.05). Les efforts inefficaces étaient moindres en VNI NAVA (résultats présentés en médiane et interquartiles) : 0% (0 - 0) en VNI NAVA vs 12% (4 - 20) en VNI conventionnelle initiale et 6% (2 - 22) en VNI conventionnelle finale (p< 0.01). Globalement, le temps passé en asynchronie a été réduit à 8% (6 - 10) en VNI NAVA, versus 27% (19 - 56) et 32% (21 - 38) en périodes de VNI conventionnelle initiale et finale, respectivement (p= 0.05). Aucune différence en termes de demande respiratoire n’a été observée. Conclusion: La VNI NAVA est faisable et bien tolérée chez les enfants avec détresse respiratoire aigüe et permet une meilleure synchronisation patient-ventilateur. De plus larges études sont nécessaires pour évaluer l’impact clinique de ces résultats.
Introduction: The need for intubation after noninvasive ventilation (NIV) failure is frequent in the pediatric intensive care unit (PICU). One reason is patient-ventilator asynchrony during NIV. Neurally adjusted ventilatory assist (NAVA) is a mode of ventilation controlled by the patient’s neural respiratory drive. The aim of this study was to assess the feasibility and tolerance of NIV-NAVA in children and to evaluate its impact on synchrony and respiratory effort. Methods: This prospective, physiologic, crossover study included 13 patients requiring NIV in the PICU of Sainte-Justine’s Hospital from October 2011 to May 2013. Patients were successively ventilated in conventional NIV as prescribed by the physician in charge (30 minutes), in NIV-NAVA (60 minutes), and again in conventional NIV (30 minutes). Electrical activity of the diaphragm (EAdi) and airway pressure were simultaneously recorded to assess patient-ventilator synchrony. Results: NIV-NAVA was feasible and well tolerated in all patients. One patient asked to stop the study early because of anxiety related to the leak-free facial mask. Inspiratory trigger dys-synchrony and cycling-off dys-synchrony were significantly shorter in NIV-NAVA versus initial and final conventional NIV periods (both p< 0.05). Wasted efforts were also decreased in NIV-NAVA (all values expressed as median and interquartile values): 0 (0 - 0) in NIV-NAVA versus 12% (4 - 20) and 6% (2 - 22) in initial and final conventional NIV, respectively (p< 0.01). As a whole, total time spent in asynchrony was reduced to 8% (6 - 10) in NIV-NAVA, versus 27% (19 - 56) and 32% (21 - 38) in initial and final conventional NIV, respectively (p= 0.05). No difference in term of respiratory effort was noted. Conclusion: NIV-NAVA is feasible and well tolerated in PICU patients and allows improved patient-ventilator synchronization. Larger controlled studies are warranted to evaluate the clinical impact of these findings.

碩士
高雄醫學大學
運動醫學系碩士在職專班
106
Background and Purpose: Pulmonary rehabilitation is a comprehensive intervention that helps with sputum clearance, promotes lung expansion, and improves muscular endurance and muscular strength, and it proves effective in relieving symptoms, manage anxiety, and improving quality of life. Despite the fact that pulmonary rehabilitation has been clinically applied to patients after surgery, postoperative pain can prevent deep breathing and coughing and result in sputum retention and atelectasis, thereby causing pneumonia, delaying the removal of the chest tube, and prolonging hospitalization. In recent years, clinical medical practitioners have actively used non-invasive positive pressure ventilation (NIPPV) on patients undergoing thoracic surgery with the aim of speeding postoperative recovery of lung function, reducing the number of days a chest tube is inserted, and shortening the length of stay in hospital. Research Methods: This study is a retrospective study looking into the medical records of patients who underwent thoracic surgery at the Kaohsiung Medical University Chung-Ho Memorial Hospital in 2015-2017. The International Classification of Diseases was adopted to collect the electronic medical records of (1) patients receiving pulmonary rehabilitation (the PR group) (January 2015-July 2016) and (2) patients receiving both pulmonary rehabilitation and non-invasive positive pressure ventilation (the PR+NIPPV group) (September 2016-April 2017). Results: V When using an incentive spirometer (Triflo), both groups reached a flow rate of 900-1,200ml one day before discharge, showing no significant difference (P=.86). A statistically significant difference was observed in the number of patients experiencing sputum clearance by bronchoscopy: seven in the PR group and one in the PR+NIPPV group (P=.03). As for the number of days a chest tube was inserted due to thoracic diseases (including those related to the lungs and esophagus), there was no statistical difference between the two groups (P=.11): 6.64±4.46 days for the PR group and 5.74±2.75 days for the PR+NIPPV group. In addition, the comparison of the number of readmission occurrences within six months of discharge due to lung collapse or pneumonia between the two groups also showed no statistical difference (0.03±0.18 for the PR group and 0.02±0.15 for the PR+NIPPV group; P=.71), indicating that both PR and PR+NIPPV had beneficial effects on postoperative complications. When the data analysis focused only on pulmonary diseases (excluding esophagus-related diseases), the average number of days a chest tube was inserted was 5.43±2.30 for the PR+NIPPV group, one day less than that of the PR group (6.62±4.58 days), and there was a significant difference between the two groups (P=.03). This study also made a statistical analysis of the number of days of hospitalization, finding no statistical different between the PR group (10.11±6.32 days on average) and the PR+NIPPV group (8.60±4.58 days on average) (P=.07). When esophagus-related diseases were excluded from the analysis of the number of days of hospital stay (i.e. focusing only on pulmonary diseases), a statistically significant difference was observed in the VI PR+NIPPV group (7.75±3.36 days on average), two days less than that of the PR group (9.86±6.48 days on average) (P=.01). Conclusion: Previous studies showed that pulmonary rehabilitation provides significant benefits to patients after surgery. This study further found that the combination of pulmonary rehabilitation and non-invasive positive pressure ventilation did help (1) reduce the number of days a chest tube was inserted after pulmonary surgery by one, (2) shorten the hospital days of patients undergoing pulmonary surgery by two, and (3) decrease the use of bronchoscopy to remove sputum. Future research can collect more cases to enhance its credibility by increasing the sample size. Requesting patients to complete a survey questionnaire is another potential tool for an objective assessment of their pain intensity and comfort level after non-invasive positive pressure ventilation. Our research findings suggest that, in addition to pulmonary rehabilitation, non-invasive positive pressure ventilation is highly recommended to patients undergoing all kinds of surgery to aid their recovery.

Einleitung: Bei PSV beendet der Respirator die Druckunterstützung, wenn der Inspirationsfluss auf einen prozentualen Anteil des Spitzenflusses, welcher als Umschaltkriterium be-zeichnet wird, absinkt. Bei obstruktiver Lungenerkrankung ist der Abfall des Inspirationsflusses verlangsamt, wodurch verspätetes Umschalten in die Exspiration begünstigt wird. Der verwendete Beatmungszugang, das etwaige Vorliegen von Leckage bei nicht-invasiver Beatmung, die Höhe der Druckunterstützung und die Atemfrequenz sind potentielle Faktoren, welche das Umschalten in die Exspiration beeinflussen können. Die synchrone Unterstützung der Patienteninspirationsbemühung ist entscheidend für den Erfolg der assistierten Beatmungstherapie. Methode: In einer Lungenmodellstudie wurde obstruktive Lungenmechanik simuliert und der Einfluss der Variation des Umschaltkriteriums auf die Patient-Respirator-Interaktion untersucht. Die Beatmungszugänge Endotrachealtubus, Nasen-Mund-Maske und Beatmungshelm wurden nacheinander in den Versuchsaufbau eingebracht. Bei nicht-invasiver Beatmung wurde mit und ohne Leckage gemessen. Bei Vorliegen von Leckage wurde zusätzlich in einem nicht-invasiven Beatmungsmodus beatmet. Die Höhe der Druckunterstützung (5 cmH2O, 15 cmH2O) und die Atemfrequenz (15/min, 30/min) wurden verändert. Die Patient-Respirator-Interaktion wurde bei Verwendung der Umschaltkriterien 10 %, 20 %, 30 %, 40 %, 50 %, 60 % und 70 % des Spitzenflusses analysiert. Aus aufgezeichneten Flusskurven wurden Parameter, welche die Synchronisation zwischen Patient und Respirator beschreiben (nicht-unterstützte Atemzüge, Doppeltrigger, inspiratorische und exspiratorische Triggerlatenz) sowie das Tidalvolumen bestimmt. Aus aufgezeichneten Druckkurven wurden der intrinsische PEEP und Druck-Zeit-Produkte bestimmt, welche in den verschiedenen Phasen des Atemzyklus die durch den Respirator geleistete Entlastung (PTPPEEP, PTPINSP) oder Belastung (PTPEXSP) der Atemmuskulatur beschreiben. Ergebnisse: Bei konventionell eingestelltem Umschaltkriterium (20 % - 30 %) wurde stets verspätetes Umschalten beobachtet. Die Erhöhung des Umschaltkriteriums resultierte in einer Reduktion der exspiratorischen Triggerlatenz, PTPEXSP und des intrinsischen PEEP. In der Folge wurden nicht-unterstützte Inspirationsbemühungen, die inspiratorischen Triggerlatenz sowie der zur Auslösung der Druckunterstützung erforderliche Kraftaufwand (PTPPEEP) reduziert. Bei übermäßiger Erhöhung des Umschaltkriteriums beendete der Respirator die Druckunterstützung vor dem Ende der simulierten Inspirationsbemühung. Vorzeitiges Umschalten ging mit einer Abnahme des Tidalvolumens und der effektive Druckunter-stützung (PTPINSP), sowie der Auslösung von Doppeltrigger, einher. Vorzeitiges Umschalten trat bei niedriger Atemfrequenz bei Verwendung der Umschaltkriterien 50 % bzw. 60 % bis 70 % auf. Bei Beatmung via Endotrachealtubus und Nasen-Mund-Maske wurden vergleichbare Ergebnisse beobachtet. Bei Beatmung via Beatmungshelm war die Interaktion zwischen Patient und Respirator wesentlich beeinträchtigt, wodurch vorzeitiges Umschalten begünstigt wurde. Bei Messungen mit Leckage war die exspiratorische Triggerlatenz verlängert. Bei Verwendung des NIV-Beatmungsmodus konnte die exspiratorische Triggerlatenz teilweise minimiert werden. Bei hoher Druckunterstützung war die exspiratorische Triggerlatenz, bei Beatmung via Endotrachealtubus und Nasen-Mund-Maske, verlängert. Konklusion: Die Variation des Umschaltkriteriums stellt eine effektive Möglichkeit dar, die Patient-Respirator-Interaktion zu optimieren. Bei obstruktiver Lungenerkrankung sollte das Umschaltkriterium, über das konventionell eingestellte Umschaltkriterium hinaus, erhöht werden. Das Umschaltkriterium ist maßvoll zu erhöhen, um eine vorzeitige Unterbrechung der Druckunterstützung zu verhindern. Das Risiko verfrühten Umschaltens ist bei Beatmung via Beatmungshelm, sowie bei niedriger Atemfrequenz, erhöht. Des Weiteren müssen das etwaige Vorliegen von Leckage, der bei nicht-invasiver Beatmung verwendete Beatmungsmodus, die Höhe der Druckunterstützung sowie die Atemfrequenz bei der Wahl des Umschaltkriteriums berücksichtigt werden.