Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 5 uppsatser.

ABSTRACT Patients with respiratory failure secondary to acute asthma exacerbation (AAE) frequently present at emergency units. Some patients may develop respiratory muscle fatigue. Current guidelines for the treatment of an AAE center on pharmacological treatment and invasive mechanical ventilation. Noninvasive positive pressure ventilation (NPPV) has an established role in COPD exacerbations. The role it can play in an AAE remains unanswered although it is frequently used in the clinical setting. Aims: The present study proposed to investigate if the early use of NPPV in the forms of continuous positive airway pressure (CPAP) or bilevel positive pressure ventilation (BPPV) together with standard medical therapy in AAE can decrease time of response to therapy compared to standard medical therapy alone. We further tested the effect of BPPV against CPAP. Methods: Asthmatic patients who presented with a severe AAE (PEFR % predicted < 60 %) at the emergency unit were randomized to either standard medical therapy (ST), ST and CPAP or ST and BPPV. Thirty patients fulfilled the inclusion criteria for the study. Groups presented similar baseline characteristics. The mean age for the group was 42.1 ± 12.6 years. Mean baseline PEFR % predicted was 35.2 ± 10.7 % (ST), 30.5 ± 11.7 % (ST + CPAP) and 33.5 ±13.8 % (ST + BPPV). Results: Hourly improvement (Δ) in respiratory rate and sensation of breathlessness was significantly better in the BPPV intervention group. Improvement (Δ) from baseline to end of treatment in respiratory rate and sensation of breathlessness was significant for both CPAP and BPPV (p = 0.0463; p = 0.0132 respectively) compared to ST alone. Lung function was significantly improved in the CPAP intervention group hourly and from baseline to end of treatment (p = 0.0403 for PEFR and p = 0.0293 for PEFR % predicted) compared to ST + BPPV and ST alone. The mean shift (Δ) in PEFR from baseline to 3 hours of treatment was 67.4, 123.5 and 86.8 L/min (p = 0.0445) for ST, ST + CPAP and ST + BPPV respectively. This corresponded to a 38.1, 80.8 and 51.7 % improvement in lung function respectively. Discussion: The effect of BPPV on the reduction of respiratory rate and sensation of breathlessness could be related to the inspiratory assistance provided by BPPV. The significant improvement in lung function in the CPAP group could be related to its intrinsic effect on the airway smooth muscle and / or on the airway smooth muscle load. Conclusion: The present results suggest that adding NPPV to standard treatment for an AAE not only improves clinical signs faster but also improves lung function faster. CPAP seems to have an intrinsic effect on the airway smooth muscle so rendering it more effective in ameliorating lung function.

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.

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.

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.

INTRODUÇÃO: A insuficiência respiratória pós-extubação é um evento comum após a descontinuação da ventilação mecânica, sendo a reintubação necessária em cerca de 10% (4-24%) dos casos. A ventilação não invasiva (VNI) tem sido considerada como uma terapia promissora para evitar a reintubação, sendo aplicada como um adjunto para extubação precoce, de forma preventiva ou em pacientes que desenvolveram insuficiência respiratória pós extubação. OBJETIVO: Comparar as características clínicas e os desfechos da população de estudo, de acordo com as três formas de aplicação da VNI no período pós extubação. MÉTODOS: Estudo observacional prospectivo em 11 Unidades de Terapia Intensiva por um período de nove meses, onde todos os pacientes adultos submetidos à VNI dentro de 48h após a extubação foram avaliados. RESULTADOS: Um total de 174 pacientes foi incluído no estudo. A média(DP) de idade foi de 56 (18) anos e 55% eram do sexo masculino. A média (DP) do SAPS II foi de 42(14). As formas de aplicação da VNI foram: Insuficiência respiratória pós-extubação (G-IRpA) (26%), como adjunto no desmame precoce (G-PRECOCE) (10%) e como VNI preventiva (G-PREVENT) (64%). O tempo mediano de tempo de ventilação mecânica foi similar nos três grupos (66h), o tempo mediano entre a extubação e o inicio da VNI foi de 0h (0-16h), e o tempo mediano entre a extubação e a reintubação foi de 2 dias (0,7-4d). Apenas 3% dos pacientes tinham DPOC. A taxa de sucesso da VNI foi de 67% no G-IRpA, 70% no G-PRECOCE e 64% no G-PREVENT, com taxa de reintubação de 34%. A taxa de mortalidade na UTI foi de 27%. Pacientes com hipercapnia tiveram uma taxa de sucesso maior (81%), já os pacientes que necessitaram de aspiração de secreção e que passaram mais tempo na VNI foram mais susceptíveis a serem reintubados. CONCLUSÃO: A VNI pode reduzir as taxas de reintubação em pacientes que apresentaram insuficiência respiratória pós extubação, apresentar um sucesso moderado em pacientes heterogêneos que a utilizaram no desmame precoce e quando utilizada em uma população não seleta de forma preventiva, não reduz, significativamente, as taxas de mortalidade e de reintubação / BACKGROUND: Respiratory failure after extubation is a common event and reintubation occurs in 10% (4-24%) of patients. Studies suggests that noninvasive ventilation (NIV) may be successfully used to avoid reintubation, being applied as an adjunct to an early extubation, to prevent postextubation respiratory failure or in patients who developed postextubation respiratory failure. OBJECTIVE: Observe the outcomes from daily routine standard use of NIV in postextubation in its three different forms of application. METHODS: A prospective observational study in 11 Intensive Care Units (ICU), was conducted over a 9 months period, it was evaluated all adult patients submitted to NIV within 48hs after extubation. RESULTS: A total of 174 patients were included in this study. The mean (SD) age was 56 (18) years, and 55% were male. The mean (SD) SAPS II was 42 (14). NIV forms of application were: (G-IRpA) posextubation respiratory failure (26%), (G-PRECOCE) as an adjunct to an early extubation (10%) and (G-PREVENT) NIV preventive (64%). The median time of mechanical ventilation was similar in the 3 groups (66 h), the median time between extubation and beginning of NIV was 0h (0-16h), and the median time between extubation and need of reintubation was 2 days (0,7-4d). There were only 2,8% COPD patients. NIV success rate was 67% in G1, 70% in G2 and 64% in G3, with reintubation rate of 34%. Mortality rate in ICU was 27%. Patients with hypercapnia had a higher success rate (80,6%), yet patients that needed secretion aspiration and that spent more time in NIV were more susceptible to be reintubated. CONCLUSION: NIV may reduce the reintubation rate in patients with respiratory failure after extubation, present a moderate success in heterogeneous patients who used in early weaning and when used in a non selected population in a preventive way does not reduce mortality and reintubation rates

INTRODUÇÃO: A insuficiência respiratória pós-extubação é um evento comum após a descontinuação da ventilação mecânica, sendo a reintubação necessária em cerca de 10% (4-24%) dos casos. A ventilação não invasiva (VNI) tem sido considerada como uma terapia promissora para evitar a reintubação, sendo aplicada como um adjunto para extubação precoce, de forma preventiva ou em pacientes que desenvolveram insuficiência respiratória pós extubação. OBJETIVO: Comparar as características clínicas e os desfechos da população de estudo, de acordo com as três formas de aplicação da VNI no período pós extubação. MÉTODOS: Estudo observacional prospectivo em 11 Unidades de Terapia Intensiva por um período de nove meses, onde todos os pacientes adultos submetidos à VNI dentro de 48h após a extubação foram avaliados. RESULTADOS: Um total de 174 pacientes foi incluído no estudo. A média(DP) de idade foi de 56 (18) anos e 55% eram do sexo masculino. A média (DP) do SAPS II foi de 42(14). As formas de aplicação da VNI foram: Insuficiência respiratória pós-extubação (G-IRpA) (26%), como adjunto no desmame precoce (G-PRECOCE) (10%) e como VNI preventiva (G-PREVENT) (64%). O tempo mediano de tempo de ventilação mecânica foi similar nos três grupos (66h), o tempo mediano entre a extubação e o inicio da VNI foi de 0h (0-16h), e o tempo mediano entre a extubação e a reintubação foi de 2 dias (0,7-4d). Apenas 3% dos pacientes tinham DPOC. A taxa de sucesso da VNI foi de 67% no G-IRpA, 70% no G-PRECOCE e 64% no G-PREVENT, com taxa de reintubação de 34%. A taxa de mortalidade na UTI foi de 27%. Pacientes com hipercapnia tiveram uma taxa de sucesso maior (81%), já os pacientes que necessitaram de aspiração de secreção e que passaram mais tempo na VNI foram mais susceptíveis a serem reintubados. CONCLUSÃO: A VNI pode reduzir as taxas de reintubação em pacientes que apresentaram insuficiência respiratória pós extubação, apresentar um sucesso moderado em pacientes heterogêneos que a utilizaram no desmame precoce e quando utilizada em uma população não seleta de forma preventiva, não reduz, significativamente, as taxas de mortalidade e de reintubação / BACKGROUND: Respiratory failure after extubation is a common event and reintubation occurs in 10% (4-24%) of patients. Studies suggests that noninvasive ventilation (NIV) may be successfully used to avoid reintubation, being applied as an adjunct to an early extubation, to prevent postextubation respiratory failure or in patients who developed postextubation respiratory failure. OBJECTIVE: Observe the outcomes from daily routine standard use of NIV in postextubation in its three different forms of application. METHODS: A prospective observational study in 11 Intensive Care Units (ICU), was conducted over a 9 months period, it was evaluated all adult patients submitted to NIV within 48hs after extubation. RESULTS: A total of 174 patients were included in this study. The mean (SD) age was 56 (18) years, and 55% were male. The mean (SD) SAPS II was 42 (14). NIV forms of application were: (G-IRpA) posextubation respiratory failure (26%), (G-PRECOCE) as an adjunct to an early extubation (10%) and (G-PREVENT) NIV preventive (64%). The median time of mechanical ventilation was similar in the 3 groups (66 h), the median time between extubation and beginning of NIV was 0h (0-16h), and the median time between extubation and need of reintubation was 2 days (0,7-4d). There were only 2,8% COPD patients. NIV success rate was 67% in G1, 70% in G2 and 64% in G3, with reintubation rate of 34%. Mortality rate in ICU was 27%. Patients with hypercapnia had a higher success rate (80,6%), yet patients that needed secretion aspiration and that spent more time in NIV were more susceptible to be reintubated. CONCLUSION: NIV may reduce the reintubation rate in patients with respiratory failure after extubation, present a moderate success in heterogeneous patients who used in early weaning and when used in a non selected population in a preventive way does not reduce mortality and reintubation rates

<p>Patienter med morbid obesitas har en ökad risk för atelektasbildning och postoperativarespiratoriska komplikationer efter generell anestesi på grund av sänkt vitalkapacitet (VC),funktionel residualkapacitet (FRC) och total lungkapacitet (TLC). Tidigare forskning har visat attPostoperativ Bi-level Positiv Airway Pressure (BIPAP) ventilations behandling minskar denna risk.Denna studie avsåg att utvärdera om postoperativ BIPAP-behandling förbättrar patienternas SpO2,paO2 , paCO2 och pH i arteriellt blod efter genomgången elektiv gastric bypass kirurgi jämfört medtraditionell postoperativ behandling. Insamlat material från 18 patienter huvudsakligen bestående avarteriella blodgaser och bakgrundsdata analyserades med analytisk statistisk. För att kunna beskrivahur patienterna upplevde BIPAP-behandlingen ställdes två öppna frågor ställdes till patienterna,.Resultatet visar att postoperativ behandling med BIPAP under 3 timmar ger högre SpO2 och lägrepaCO2 än traditionell postoperativ behandling efter elektiv gastric bypass kirurgi. Vid bådabehandlingarna sjunker paO2 och pH är oförändrat. Flera av patienterna upplevde besvär av BIPAPbehandlingen.</p> / <p>Obese patients have a higher risk for respiratory complications after general anesthesia related toreduced vital capacity (VC), functional residual capacity (FRC) and total lung capacity (TLC).Earlier studies have shown that postoperative treatment with Bi-level Positive Airway Pressureimproved forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1.0) andsaturation (SpO2) after elective gastric bypass surgery. Present study evaluates whether or not thesame postoperative treatment also shows differences in arterial blood gases, if compared with usualpostoperative treatment with nasal administered oxygen. A second aim was to describe how patientsexperienced the BIPAP treatment. Arterial blood gases from 18 patients were analyzed withanalytical statistics. The study showed that postoperative treatment whit BIPAP during 3 hoursresults in higher SpO2 and lower paCO2 than traditional postoperative treatment after electivegastric bypass surgery. Both treatments results in lower paO2 and unchanged pH. Several patientsexperienced discomfort during the BIPAP treatment.</p>

Patienter med morbid obesitas har en ökad risk för atelektasbildning och postoperativarespiratoriska komplikationer efter generell anestesi på grund av sänkt vitalkapacitet (VC),funktionel residualkapacitet (FRC) och total lungkapacitet (TLC). Tidigare forskning har visat attPostoperativ Bi-level Positiv Airway Pressure (BIPAP) ventilations behandling minskar denna risk.Denna studie avsåg att utvärdera om postoperativ BIPAP-behandling förbättrar patienternas SpO2,paO2 , paCO2 och pH i arteriellt blod efter genomgången elektiv gastric bypass kirurgi jämfört medtraditionell postoperativ behandling. Insamlat material från 18 patienter huvudsakligen bestående avarteriella blodgaser och bakgrundsdata analyserades med analytisk statistisk. För att kunna beskrivahur patienterna upplevde BIPAP-behandlingen ställdes två öppna frågor ställdes till patienterna,.Resultatet visar att postoperativ behandling med BIPAP under 3 timmar ger högre SpO2 och lägrepaCO2 än traditionell postoperativ behandling efter elektiv gastric bypass kirurgi. Vid bådabehandlingarna sjunker paO2 och pH är oförändrat. Flera av patienterna upplevde besvär av BIPAPbehandlingen. / Obese patients have a higher risk for respiratory complications after general anesthesia related toreduced vital capacity (VC), functional residual capacity (FRC) and total lung capacity (TLC).Earlier studies have shown that postoperative treatment with Bi-level Positive Airway Pressureimproved forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1.0) andsaturation (SpO2) after elective gastric bypass surgery. Present study evaluates whether or not thesame postoperative treatment also shows differences in arterial blood gases, if compared with usualpostoperative treatment with nasal administered oxygen. A second aim was to describe how patientsexperienced the BIPAP treatment. Arterial blood gases from 18 patients were analyzed withanalytical statistics. The study showed that postoperative treatment whit BIPAP during 3 hoursresults in higher SpO2 and lower paCO2 than traditional postoperative treatment after electivegastric bypass surgery. Both treatments results in lower paO2 and unchanged pH. Several patientsexperienced discomfort during the BIPAP treatment.

There are few recommendations on how best to apply certain modes of mechanical ventilation. The application of Airway Pressure Release Ventilation (APRV) includes strategic implementation of specific inspiratory times (I-times) and particular mean airway pressures (MAWP) neither of which is standardized. This study utilized a retrospective analysis of archived electronic health record data to evaluate the clinical outcomes of adult patients that had been placed on APRV for at least 8 hours. 68 adult subjects were evaluated as part of a convenient purposive sample. All outcomes of interest (surrogates) for short-term clinical outcomes to include the PaO2/FiO2 (P/F) ratio, Oxygen Index and Oxygen Saturation Index (OI; OSI), and Modified Sequential Organ Failure Assessment (MSOFA) scores showed improvement after at least 8 hours on APRV. Most notably, there was significant improvement in P/F ratio (p = .012) and OSI (p = .000). Results of regression analysis showed P low as a statistically significant negative predictor of pre-APRV P/F ratio with a higher initial P low coinciding with a lower P/F ratio. The regression analysis also showed MAWP as a significant positive predictor of post-APRV OSI and P high and P low as significant negative predictors of post-APRV MSOFA scores. In summary, it was found that settings for P high, Plow, and T low in addition to overall MAWP and Body Mass Index (BMI) had significant correlation to impact at least one of the short-term clinical outcomes measured.