| 1. |
- Andersson, Lars-Göran, et al.
(author)
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Thallium-201 Myocardial Imaging at Rest in Male Orienteers and Other Endurance Athletes
- 2001
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In: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 106:1, s. 59-66
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Journal article (peer-reviewed)abstract
- During the period 1979 to 1992, 16 sudden unexpected cardiac deaths were known to have occurred in young Swedish orienteers. Autopsy indicated myocarditis to be the most frequent finding, most often combined with extensive myocardial fibrosis. The aim of the present investigation was to explore whether young male orienteers show a higher frequency than other young elite endurance athletes (controls) in the occurrence of Thallium-201 myocardial perfusion defects at rest, suggestive of fibrosis evoked by myocarditis. Thallium-201 perfusion abnormalities at rest were more frequently found in the controls than in the orienteers (26% vs. 12%, p=0.03). Uneven Tl-201 perfusion was associated with left ventricular mass (r=0.32, r=0.24, p<0.01, p=0.02) and body weight (r=0.30, r=0.31, p<0.01, p=0.03) in orienteers and controls, respectively. Echocardiographic left ventricular wall motion abnormalities were found in 11 athletes (9 orienteers and 2 controls) but only two displayed an abnormal Thallium-201 perfusion scan at rest. Perfusion abnormalities at rest did not occur more frequently in the orienteers but were commonly found in both groups of apparently healthy athletes making it futile to discern abnormals from normals. Thallium-201 perfusion aberrations were not associated with left ventricular wall motion abnormalities obtained by echocardiography.
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| 2. |
- Damm, S., et al.
(author)
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Wall motion abnormalities in male elite orienteers are aggravated by exercise
- 1999
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In: Clinical Physiology. - : Wiley. - 0144-5979 .- 1365-2281. ; 19:2, s. 121-126
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Journal article (peer-reviewed)abstract
- During the period 1979-92, 16 (15 men and one woman) sudden unexpected cardiac deaths occurred among young Swedish orienteers. This finding indicated a sharp increase in the death rate of orienteers, and necropsy demonstrated that myocarditis was a common histopathological finding. Therefore, an extensive non-invasive cardiac investigation was performed. A total of 59 male élite orienteers (mean age 23 years) and 36 cross-country skiers and middle-distance runners (mean age 22 years), serving as controls, were examined by both echocardiography at rest and radionuclide ventriculography at rest and during exercise. Wall motion abnormalities were found in eight orienteers using echocardiography. The purpose of this study was to examine whether the group of orienteers with wall motion abnormalities found using echocardiography had a smaller increase in ejection fraction from rest to exercise using radionuclide ventriculography than the rest of the orienteers and the controls, indicating an aggravation of the wall motion abnormalities during exercise. There were no significant differences in the ejection fraction at rest between the groups. In the orienteers with wall motion abnormalities (group 1), 62% (five out of eight) had less than a 0.05 unit increase in left ventricular ejection fraction compared with 27% (14 out of 51) of the remaining orienteers (group 2) and 19% (7 out of 36) of the controls (group 3). A comparison of athletes in group 1 with those in groups 2 and 3 combined revealed a statistically significant difference (P < 0.05). The divergent response in left ventricular ejection fraction during exercise suggests an aggravation of the wall motion abnormalities with exercise. Both the echocardiographic and the radionuclide ventriculographic findings indicate that the orienteers in group 1 had concealed left ventricular damage.
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| 3. |
- Hedenstierna, Göran, 1941-, et al.
(author)
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Nitric oxide dosed in short bursts at high concentrations may protect against Covid 19.
- 2020
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In: Nitric oxide. - : Elsevier. - 1089-8603 .- 1089-8611. ; 103, s. 1-3
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Journal article (peer-reviewed)abstract
- It has long been suggested that NO may inhibit an early stage in viral replication. Furthermore, in vitro tests have shown that NO inhibits the replication cycle of severe acute respiratory syndrome coronavirus. Despite smoking being listed as a risk factor to contract Covid-19, only a low proportion of the smokers suffered from SARS-corona infection in China 2003, and from Covid-19 in China, Europe and the US. We hypothesize, that the intermittent bursts of high NO concentration in cigarette smoke may be a mechanism in protecting against the virus. Mainstream smoke from cigarettes contains NO at peak concentrations of between about 250 ppm and 1350 ppm in each puff as compared to medicinal use of no more than 80 to a maximum of 160 ppm. The diffusion of NO through the cell wall to reach the virus should be significantly more effective at the very high NO concentration in the smoke, according to classic laws of physics. The only oxide of nitrogen in the mainstream smoke is NO, and the NO2 concentration that is inhaled is very low or undetectable, and methemoglobin levels are lower in smokers than non-smokers, reasonably explained by the breaths of air in between the puffs that wash out the NO. Specialized iNO machines can now be developed to provide the drug intermittently in short bursts at high concentration dose, which would then provide both a preventative drug for those at high risk, as well as an effective treatment, without the health hazards associated with smoking.
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| 4. |
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| 5. |
- Rothen, Hans Ulrich, et al.
(author)
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Influence of gas composition on recurrence of atelectasis after a reexpansion maneuver during general anaesthesia
- 1995
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In: Anesthesiology. - 0003-3022 .- 1528-1175. ; 82:4, s. 832-842
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Journal article (peer-reviewed)abstract
- BACKGROUND:Atelectasis, an important cause of impaired gas exchange during general anesthesia, may be eliminated by a vital capacity maneuver. However, it is not clear whether such a maneuver will have a sustained effect. The aim of this study was to determine the impact of gas composition on reappearance of atelectasis and impairment of gas exchange after a vital capacity maneuver.METHODS:A consecutive sample of 12 adults with healthy lungs who were scheduled for elective surgery were studied. Thirty minutes after induction of anesthesia with fentanyl and propofol, the lungs were hyperinflated manually up to an airway pressure of 40 cmH2O. FIO2 was either kept at 0.4 (group 1, n = 6) or changed to 1.0 (group 2, n = 6) during the recruitment maneuver. Atelectasis was assessed by computed tomography. The amount of dense areas was measured at end-expiration in a transverse plane at the base of the lungs. The ventilation-perfusion distributions (VA/Q) were estimated with the multiple inert gas elimination technique. The static compliance of the total respiratory system (Crs) was measured with the flow interruption technique.RESULTS:In group 1 (FIO2 = 0.4), the recruitment maneuver virtually eliminated atelectasis for at least 40 min, reduced shunt (VA/Q < 0.005), and increased at the same time the relative perfusion to poorly ventilated lung units (0.005 < VA/Q < 0.1; mean values are given). The arterial oxygen tension (PaO2) increased from 137 mmHg (18.3 kPa) to 163 mmHg (21.7 kPa; before and 40 min after recruitment, respectively; P = 0.028). In contrast to these findings, atelectasis recurred within 5 min after recruitment in group 2 (FIO2 = 1.0). Comparing the values before and 40 min after recruitment, all parameters of VA/Q were unchanged. In both groups, Crs increased from 57.1/55.0 ml.cmH2O-1 (group 1/group 2) before to 70.1/67.4 ml.cmH2O-1 after the recruitment maneuver. Crs showed a slow decrease thereafter (40 min after recruitment: 61.4/60.0 ml.cmH2O-1), with no difference between the two groups.CONCLUSIONS:The composition of inspiratory gas plays an important role in the recurrence of collapse of previously reexpanded atelectatic lung tissue during general anesthesia in patients with healthy lungs. The reason for the instability of these lung units remains to be established. The change in the amount of atelectasis and shunt appears to be independent of the change in the compliance of the respiratory system.
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| 6. |
- Ahlgren, Sara, 1979-
(author)
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Molecular Radionuclide Imaging Using Site-specifically Labelled Recombinant Affibody Molecules : Preparation and Preclinical Evaluation
- 2010
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Doctoral thesis (other academic/artistic)abstract
- Radionuclide molecular imaging is an emerging multidisciplinary technique that is used in modern medicine to visualise diseases at cellular and molecular levels. This thesis is based on five papers (I-V) and focuses on the development of site-specific radiolabelled recombinant anti-HER2 Affibody molecules and preclinical evaluations in vitro and in vivo of the labelled conjugates. This work is part of a preclinical development of an Affibody molecule-based tracer for molecular imaging of HER2 expressing tumours. Papers I and II report the evaluation of the Affibody molecule ZHER2:2395-C, site-specifically labelled with the radiometals 111In (for SPECT) and 57Co (as a surrogate for 55Co, suitable for PET applications) using a thiol reactive DOTA derivative as a chelator. Both conjugates demonstrated very suitable biodistribution properties, enabling high contrast imaging just a few hours after injection. Papers III and IV report the development and optimization of a technique for site-specific labelling of ZHER2:2395-C with 99mTc using an N3S chelating peptide sequence. 99mTc-ZHER2:2395-C demonstrated high and specific tumour uptake and rapid clearance of non-bound tracer from the blood, resulting in high tumour-to-non-tumour ratios shortly after injection, enabling high contrast imaging. In addition, in the study described in paper IV, freeze-dried kits previously developed for 99mTc-labelling were optimised, resulting in the development of a kit in which all the reagents and protein needed for labelling of ZHER2:2395-C with 99mTc were contained in a single vial. Paper V reports the evaluation of an anti-HER2 Affibody molecule, ABY-025, with a fundamentally re-engineered scaffold. Despite the profound re-engineering, the biodistribution pattern of 111In-ABY-025 was very similar to that of two variants of the parental molecule. It seems reasonable to believe that these results will also be applicable to Affibody molecules towards other targets. Hopefully, this work will also be helpful in the development of other small proteinaceous tracers.
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| 7. |
- Akaberi, Dario, 1989-, et al.
(author)
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Mitigation of the replication of SARS-CoV-2 by nitric oxide in vitro
- 2020
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In: Redox Biology. - : Elsevier. - 2213-2317. ; 37
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Journal article (peer-reviewed)abstract
- The ongoing SARS-CoV-2 pandemic is a global public health emergency posing a high burden on nations' health care systems and economies. Despite the great effort put in the development of vaccines and specific treatments, no prophylaxis or effective therapeutics are currently available. Nitric oxide (NO) is a broad-spectrum antimicrobial and a potent vasodilator that has proved to be effective in reducing SARS-CoV replication and hypoxia in patients with severe acute respiratory syndrome. Given the potential of NO as treatment for SARS-CoV-2 infection, we have evaluated the in vitro antiviral effect of NO on SARS-CoV-2 replication. The NO-donor S-nitroso-N-acetylpenicillamine (SNAP) had a dose dependent inhibitory effect on SARS-CoV-2 replication, while the non S-nitrosated NAP was not active, as expected. Although the viral replication was not completely abolished (at 200 μM and 400 μM), SNAP delayed or completely prevented the development of viral cytopathic effect in treated cells, and the observed protective effect correlated with the level of inhibition of the viral replication. The capacity of the NO released from SNAP to covalently bind and inhibit SARS-CoV-2 3CL recombinant protease in vitro was also tested. The observed reduction in SARS-CoV-2 protease activity was consistent with S-nitrosation of the enzyme active site cysteine.
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| 8. |
- Akca, Ozan, et al.
(author)
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WHO Needs High FIO2?
- 2017
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In: TURKISH JOURNAL OF ANAESTHESIOLOGY AND REANIMATION. - : AVES. - 2149-0937. ; 45:4, s. 181-192
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Journal article (peer-reviewed)abstract
- World Health Organization and the United States Center for Disease Control have recently recommended the use of 0.8 FIO2 in all adult surgical patients undergoing general anaesthesia, to prevent surgical site infections. This recommendation has arisen several discussions: As a matter of fact, there are numerous studies with different results about the effect of FIO2 on surgical site infection. Moreover, the clinical effects of FIO2 are not limited to infection control. We asked some prominent authors about their comments regarding the recent recommendations
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| 9. |
- Aliverti, A., et al.
(author)
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Effects of propofol anaesthesia on thoraco-abdominal volume variations during spontaneous breathing and mechanical ventilation
- 2011
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In: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 55:5, s. 588-596
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Journal article (peer-reviewed)abstract
- Background Anaesthesia based on inhalational agents has profound effects on chest wall configuration and breathing pattern. The effects of propofol are less well characterised. The aim of the current study was to evaluate the effects of propofol anaesthesia on chest wall motion during spontaneous breathing and positive pressure ventilation. Methods We studied 16 subjects undergoing elective surgery requiring general anaesthesia. Chest wall volumes were continuously monitored by opto-electronic plethysmography during quiet breathing (QB) in the conscious state, induction of anaesthesia, spontaneous breathing during anaesthesia (SB), pressure support ventilation (PSV) and pressure control ventilation (PCV) after muscle paralysis. Results The total chest wall volume decreased by 0.41 +/- 0.08 l immediately after induction by equal reductions in the rib cage and abdominal volumes. An increase in the rib cage volume was then seen, resulting in total chest wall volumes 0.26 +/- 0.09, 0.24 +/- 0.10, 0.22 +/- 0.10 l lower than baseline, during SB, PSV and PCV, respectively. During QB, rib cage volume displacement corresponded to 34.2 +/- 5.3% of the tidal volume. During SB, PSV and PCV, this increased to 42.2 +/- 4.9%, 48.2 +/- 3.6% and 46.3 +/- 3.2%, respectively, with a corresponding decrease in the abdominal contribution. Breathing was initiated by the rib cage muscles during SB. Conclusion Propofol anaesthesia decreases end-expiratory chest wall volume, with a more pronounced effect on the diaphragm than on the rib cage muscles, which initiate breathing after apnoea.
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| 10. |
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| 11. |
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| 12. |
- Andren, Bertil, et al.
(author)
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The influence of body composition on left ventricular mass and other echocardiographic and Doppler measurements in 70-year-old males
- 1995
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In: Clinical Physiology. - 0144-5979 .- 1365-2281. ; 15:5, s. 425-433
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Journal article (peer-reviewed)abstract
- Heart morphology and function are often related to body size. The most common way to standardize for body composition is to divide these measures by body surface area (BSA). It has, however, been suggested that left ventricular mass (LV mass) ought to be indexed for height and that cardiac output is influenced by the body fat distribution.As part of a health screening programme of 70-year-old males in Uppsala, Sweden, 100 consecutive men were investigated with echocardiography and Doppler with regard to cardiac morphology and function. These measures were related to an evaluation of body composition using an X-ray method (dual energy X-ray absorptiometry).Lean body mass was strongly related to BSA and body weight (r=0.90 and 0.89, respectively; P<0.001), and to a lesser degree to height (r=0.70, P<0.0001). In the healthy part of the population (n=39), relationships between LV mass on the one hand and lean body mass, BSA and height on the other were seen (r=0.51, 0.51 and 0.50, respectively; P<0.01). Stroke volume calculated according to Teichholtz (but not when calculated with Doppler) showed a significant correlation to lean body mass (r=0.38, P<0.05). Also, left ventricular diameter and the thickness of the free wall were related to lean body mass (r=0.40 and 0.39, respectively; P<0.05). All of the evaluated relationships were generally weaker and in most cases no longer significant when evaluated in the part of the population with diseases known to affect the heart.No significant correlations were seen between the size of the left atrium, septal thickness or indices of diastolic function (E/A-ratio, isovolumic relaxation time, deceleration time) and the indices of body composition. No measures of cardiac morphology and function were significantly related to the amount of body fat or body bone.LV mass, stroke volume and left ventricular diameter were found to be correlated with lean body mass, but not with the amount of fat, in healthy 70-year-old males.
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| 30. |
- Antonelli, Massimo, et al.
(author)
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Year in review in Intensive Care Medicine 2012. II : Pneumonia and infection, sepsis, coagulation, hemodynamics, cardiovascular and microcirculation, critical care organization, imaging, ethics and legal issues
- 2013
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In: Intensive Care Medicine. - : Springer Science and Business Media LLC. - 0342-4642 .- 1432-1238. ; 39:3, s. 345-364
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Journal article (peer-reviewed)
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| 31. |
- Appelberg, Jonas, 1964-, et al.
(author)
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Lung aeration during sleep
- 2007
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In: Chest. - : Elsevier BV. - 0012-3692 .- 1931-3543. ; 131:1, s. 122-129
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Journal article (peer-reviewed)abstract
- Background: During sleep, ventilation and functional residual capacity (FRC) decrease slightly. This study addresses regional lung aeration during wakefulness and sleep. Methods: Ten healthy subjects underwent spirometry awake and with polysomnography, including pulse oximetry, and also CT when awake and during sleep. Lung aeration in different lung regions was analyzed. Another three subjects were studied awake to develop a protocol for dynamic CT scanning during breathing. Results: Aeration in the dorsal, dependent lung region decreased from a mean of 1.14 ± 0.34 mL (± SD) of gas per gram of lung tissue during wakefulness to 1.04 ± 0.29 mL/g during non-rapid eye movement (NREM) sleep (- 9%) [p = 0.034]. In contrast, aeration increased in the most ventral, nondependent lung region, from 3.52 ± 0.77 to 3.73 ± 0.83 mL/g (+ 6%) [p = 0.007]. In one subject studied during rapid eye movement (REM) sleep, aeration decreased from 0.84 to 0.65 mL/g (- 23%). The fall in dorsal lung aeration during sleep correlated to awake FRC (R2 = 0.60; p = 0.008). Airway closure, measured awake, occurred near and sometimes above the FRC level. Ventilation tended to be larger in dependent, dorsal lung regions, both awake and during sleep (upper region vs lower region, 3.8% vs 4.9% awake, p = 0.16, and 4.5% vs 5.5% asleep, p = 0.09, respectively). Conclusions: Aeration is reduced in dependent lung regions and increased in ventral regions during NREM and REM sleep. Ventilation was more uniformly distributed between upper and lower lung regions than has previously been reported in awake, upright subjects. Reduced respiratory muscle tone and airway closure are likely causative factors.
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| 32. |
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| 33. |
- Appelberg, Jonas, 1964-, et al.
(author)
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Lung aeration during sleep in patients with obstructive sleep apnoea
- 2010
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In: Clinical Physiology and Functional Imaging. - Oxford : Blackwell Publishing. - 1475-0961 .- 1475-097X. ; 30:4, s. 301-307
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Journal article (peer-reviewed)abstract
- P>Background: Previous studies have indicated that patients with obstructive sleep apnoea (OSA) have altered ventilation and lung volumes awake and the results suggest that this may be a determinant of severity of desaturations during sleep. However, little is known about regional lung aeration during sleep in patients with OSA. Methods: Twelve patients with OSA were included in the study. Computed tomography was used to study regional lung aeration during wakefulness and sleep. Lung aeration was calculated in ml gas/g lung tissue in four different regions of interest (ROI1-4), along the border of the lung from ventral to dorsal. Results: Lung aeration in the dorsal (dependent) lung region (ROI4) was lower during sleep compared to wakefulness 0 center dot 78 +/- 0 center dot 19 versus 0 center dot 88 +/- 0 center dot 19 (mean +/- SD) ml gas/g lung tissue (P = 0 center dot 005). Associations were found between awake expiratory reserve volume and change in lung aeration from wakefulness to sleep in ROI4 (r = -0 center dot 69; P = 0 center dot 012). In addition, the change in lung aeration in the dorsal region correlated to sleep time (r = 0 center dot 69; P = 0 center dot 014) but not to time in supine position. The difference in lung aeration between inspiration and expiration (i.e. ventilation), was larger in the ventral lung region when expressed as ml gas per g lung tissue. In two patients it was noted that, during on-going obstructive apnoea, lung aeration tended to be increased rather than decreased. Conclusions: Aeration in the dorsal lung region is reduced during sleep in patients with OSA. The decrease is related to lung volume awake and to sleep time.
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| 34. |
- Appelberg, Jonas, 1964-
(author)
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Ventilation and Lung Volume During Sleep and in Obstructive Sleep Apnea
- 2003
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Doctoral thesis (other academic/artistic)abstract
- Obstructive sleep apnea (OSA) appears to affect up to 5% of the population. The extent to what pulmonary function awake and during sleep relates to obstructive breathing and hypoxemia during sleep in these patients is unclear. The aim of this study was to investigate respiratory function in patients with varying degree of snoring and OSA and to analyse regional lung aeration during sleep.In all, 35 healthy subjects and 90 patients with snoring and OSA were studied. The ventilatory response to CO2 (VRCO2) was measured. Lung function tests were performed. A technique based on computed tomography was developed to study lung aeration during sleep.Patients with OSA displayed a higher VRCO2 in comparison to healthy subjects and snorers (p<0.01). Increased closing volume and reduced expiratory reserve volume (ERV) were found in patients with OSA (p<0.001). In a multiple regression analysis, ERV was an independent predictor of nocturnal apnea (R2=0.13; p=0.001) and desaturation frequency (R2=0.11; p<0.01). In both healthy subjects and OSA patients, lung aeration was reduced during sleep by 0.10 ml gas/g tissue in the dorsal lung region (p<0.05 and p<0.01). OSA patients had a significantly lower gas/tissue ratio in comparison to healthy subjects both awake (-23%; p<0.04) and during sleep (-25%; p<0.04). In a univariate analysis, functional residual capacity (FRC) correlated with the change in lung aeration from wakefulness to sleep (r=-0.78; p<0.001). In patients with OSA, ERV (r=-0.69; p<0.05) and sleep time (r=0.69; p<0.05) correlated with the fall in lung aeration. In conclusion, patients with OSA display an increased ventilatory response to CO2, reduced ERV and increased closing volume. ERV predicts nocturnal apnea and desaturation frequency to a similar extent as obesity. Lung aeration is reduced in the dorsal region during sleep and patients with OSA display a lower amount of gas in comparison to healthy subjects. Decrease in lung volumes, promoting airway closure, and loss of muscle tone contributed to the altered lung function during sleep.
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| 35. |
- Auckburally, Adam, et al.
(author)
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Effects of pulsed inhaled nitric oxide delivery on the distribution of pulmonary perfusion in spontaneously breathing and mechanically ventilated anesthetized ponies
- 2022
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In: American Journal of Veterinary Research. - : American Veterinary Medical Association (AVMA). - 0002-9645 .- 1943-5681. ; 83, s. 171-179
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Journal article (peer-reviewed)abstract
- OBJECTIVETo measure changes in pulmonary perfusion during pulsed inhaled nitric oxide (PiNO) delivery in anesthetized, spontaneously breathing and mechanically ventilated ponies positioned in dorsal recumbency.ANIMALS6 adult ponies.PROCEDURESPonies were anesthetized, positioned in dorsal recumbency in a CT gantry, and allowed to breathe spontaneously. Pulmonary artery, right atrial, and facial artery catheters were placed. Analysis time points were baseline, after 30 minutes of PiNO, and 30 minutes after discontinuation of PiNO. At each time point, iodinated contrast medium was injected, and CT angiography was used to measure pulmonary perfusion. Thermodilution was used to measure cardiac output, and arterial and mixed venous blood samples were collected simultaneously and analyzed. Analyses were repeated while ponies were mechanically ventilated.RESULTSDuring PiNO delivery, perfusion to aerated lung regions increased, perfusion to atelectatic lung regions decreased, arterial partial pressure of oxygen increased, and venous admixture and the alveolar-arterial difference in partial pressure of oxygen decreased. Changes in regional perfusion during PiNO delivery were more pronounced when ponies were spontaneously breathing than when they were mechanically ventilated.CLINICAL RELEVANCEIn anesthetized, dorsally recumbent ponies, PiNO delivery resulted in redistribution of pulmonary perfusion from dependent, atelectatic lung regions to nondependent aerated lung regions, leading to improvements in oxygenation. PiNO may offer a treatment option for impaired oxygenation induced by recumbency.
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| 41. |
- Baumgardner, James E., et al.
(author)
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Effect of Global Ventilation to Perfusion Ratio, for Normal Lungs, on Desflurane and Sevoflurane Elimination Kinetics
- 2021
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In: Anesthesiology. - : Lippincott Williams & Wilkins. - 0003-3022 .- 1528-1175. ; 135:6, s. 1042-1054
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Journal article (peer-reviewed)abstract
- Background: Kinetics of the uptake of inhaled anesthetics have been well studied, but the kinetics of elimination might be of more practical importance. The objective of the authors' study was to assess the effect of the overall ventilation/perfusion ratio (V-A/Q), for normal lungs, on elimination kinetics of desflurane and sevoflurane.Methods: The authors developed a mathematical model of inhaled anesthetic elimination that explicitly relates the terminal washout time constant to the global lung V-A/Q ratio. Assumptions and results of the model were tested with experimental data from a recent study, where desflurane and sevoflurane elimination were observed for three different V-A/Q conditions: normal, low, and high.Results: The mathematical model predicts that the global V-A/Q ratio, for normal lungs, modifies the time constant for tissue anesthetic washout throughout the entire elimination. For all three V-A/Q conditions, the ratio of arterial to mixed venous anesthetic partial pressure P-art/P-mv reached a constant value after 5 min of elimination, as predicted by the retention equation. The time constant corrected for incomplete lung clearance was a better predictor of late-stage kinetics than the intrinsic tissue time constant.Conclusions: In addition to the well-known role of the lungs in the early phases of inhaled anesthetic washout, the lungs play a long-overlooked role in modulating the kinetics of tissue washout during the later stages of inhaled anesthetic elimination. The V-A/Q ratio influences the kinetics of desflurane and sevoflurane elimination throughout the entire elimination, with more pronounced slowing of tissue washout at lower V-A/Q ratios.
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| 42. |
- Baumgardner, James E., et al.
(author)
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Ventilation/perfusion distributions revisited
- 2016
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In: Current Opinion in Anaesthesiology. - 0952-7907 .- 1473-6500. ; 29:1, s. 2-7
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Research review (peer-reviewed)abstract
- Purpose of reviewA major cause of hypoxemia in anesthesia is ventilation-perfusion (V-A/Q) mismatch. With more advanced surgery and an aging population, monitoring of V-A/Q is of increasing importance.Recent findingsThe classic multiple inert gas elimination technique has been simplified with a new approach based on mass spectrometry. V-A/Q distributions can also be measured, at the bedside, by varying inspired oxygen concentration. MRI, 3-dimensional single photon emission computed tomography, positron emission tomography, and electrical impedance tomography enable imaging of perfusion and ventilation, and in some of the techniques also the distribution of inflammation. One-lung ventilation with thoracoscopy and capnothorax require careful monitoring of V-A/Q, made possible bedside by electrical impedance tomography. Carbon dioxide, but not air, for pneumoperitoneum enhances shift of perfusion to ventilated regions. Ventilatory support during cardiopulmonary resuscitation causes less V-A/Q mismatch when inspired oxygen concentrations are lower. Mechanisms of redistribution of lung blood flow by inhaled nitric oxide include endothelin-mediated vasoconstriction in collapsed lung regions.SummaryMethods are continuously developing to simplify measurement of V-A/Q and also to relate V-A/Q to inflammation. The recording of V-A/Q has helped to explain important aspects of gas exchange in thoracic anesthesiology and in intensive care medicine.
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| 43. |
- Bense, Laszlo, et al.
(author)
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Right main bronchus perforation detected by 3D-image
- 2011
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In: BMJ Case Reports. - : BMJ. - 1757-790X.
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Journal article (peer-reviewed)abstract
- A male metal worker, who has never smoked, contracted debilitating dyspnoea in 2003 which then deteriorated until 2007. Spirometry and chest x-rays provided no diagnosis. A 3D-image of the airways was reconstructed from a high-resolution CT (HRCT) in 2007, showing peribronchial air on the right side, mostly along the presegmental airways. After digital subtraction of the image of the peribronchial air, a hole on the cranial side of the right main bronchus was detected. The perforation could be identified at the re-examination of HRCTs in 2007 and 2009, but not in 2010 when it had possibly healed. The occupational exposure of the patient to evaporating chemicals might have contributed to the perforation and hampered its healing. A 3D HRCT reconstruction should be considered to detect bronchial anomalies, including wall-perforation, when unexplained dyspnoea or other chest symptoms call for extended investigation.
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| 44. |
- Bergmann, Astrid, et al.
(author)
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Data on the effects of remote ischemic preconditioning in the lungs after one-lung ventilation
- 2018
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In: Data in Brief. - : Elsevier BV. - 2352-3409. ; 21, s. 441-448
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Journal article (peer-reviewed)abstract
- This article contains data on experimental endpoints of a randomized controlled animal trial. Fourteen healthy piglets underwent mechanical ventilation including injurious one-lung ventilation (OLV), seven of them experienced four cycles of remote ischemic preconditioning (RIP) on one hind limb immediately before OLV, seven of them did not receive RIP and served as controls, in a randomized manner. The two major endpoints were (1) pulmonary damage assessed with the diffuse alveolar damage (DAD) score and (2) the inflammatory response assessed by cytokine concentrations in serum and in bronchoalveolar lavage fluids (BAL). The cytokine levels in the homogenized lung tissue samples are presented in the original article. Further interpretation and discussion of these data can be found in Bergmann et al. (in press).
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| 45. |
- Bergmann, Astrid, et al.
(author)
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Early and late effects of remote ischemic preconditioning on spirometry and gas exchange in healthy volunteers
- 2020
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In: Respiratory Physiology & Neurobiology. - : Elsevier BV. - 1569-9048 .- 1878-1519. ; 271
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Journal article (peer-reviewed)abstract
- Purpose: Remote ischemic preconditioning (RIP) may protect remote organs from ischemia-reperfusion-injury (IRI) in surgical and non-surgical patients. There are few data available on RIP and lung function, especially not in healthy volunteers. The null-hypothesis was tested that RIP does not have an effect on pulmonary function when applied on healthy volunteers that were breathing spontaneously and did not experience any intervention. After approval of the Ethics Committee and informed consent of the study subjects, 28 healthy non-smoking volunteers were included and randomized in either the RIP group (n = 13) or the control group (n = 15). In the RIP group, lower limb ischemia was induced by inflation of a blood pressure cuff to a pressure 20 mmHg above the systolic blood pressure. After five minutes the blood pressure cuff was released for five minutes rest. The procedure was repeated three times resulting in 40 min ischemia and reperfusion. Capillary blood samples were taken, and lung function tests were performed at baseline (T1) and 60 min (T2) and 24 h (T3) after RIP. The control group was treated in the same fashion, but the RIP procedure was replaced by a sham protocol.Results: 60 min after RIP capillary pO(2) decreased significantly and returned to baseline level after 24 h in the RIP group. This did not occur in the control group. Capillary pCO(2), variables of lung function tests and pulmonary capillary blood volume remained unchanged throughout the experiment in both groups.Conclusion: Oxygenation is impaired early after RIP which is possibly induced by transient ventilation-perfusion inequality. No late effects of RIP were observed. The null hypothesis has to be rejected that RIP has no effect on respiratory variables in healthy volunteers.
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| 46. |
- Bergmann, Astrid, et al.
(author)
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Effect of remote ischemic preconditioning on exhaled nitric oxide concentration in piglets during and after one-lung ventilation
- 2020
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In: Respiratory Physiology & Neurobiology. - : Elsevier BV. - 1569-9048 .- 1878-1519. ; 276
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Journal article (peer-reviewed)abstract
- BACKGROUND: Remote ischemic preconditioning (RIP) may protect target organs from ischemia - reperfusion injury, however, little is known on pulmonary effects of RIP prior to, immediately after and several hours after one-lung ventilation (OLV). The present randomized, controlled, animal experiment was undertaken to analyze these issues.METHODS: After animal ethics committee approval, twelve piglets (26 ± 2 kg) were anesthetized and randomly assigned to a control (n = 6) or to a RIP group (n = 6). For RIP, arterial perfusion of a hind limb was suspended by an inflated blood pressure cuff (200 mmHg for 5 min) and deflated for another 5 min, this was repeated four times. After intubation, mechanical ventilation (MV) was kept constant with tidal volume 10 ml/kg, inspired oxygen fraction (FIO2) 0.40, and positive end-expiratory pressure (PEEP) 5cmH2O. FIO2 was increased to 1 after RIP in the RIP group and after the sham procedure in the control group, respectively, for the time of OLV. OLV was established by left-sided bronchial blockade. After OLV, TLV was re-established until the end of the protocol. Exhaled nitric oxide (NO) was measured by ozon chemiluminiscense and ventilatory and hemodynamic variables were assessed according to the protocol.RESULTS: Hemodynamic and respiratory data were similar in both groups. Arterial pO2 was higher in the RIP group after two hours of OLV. In the control group, exhaled NO decreased during OLV and remained at low levels for the rest of the protocol. In the RIP group, exhaled NO decreased as well during OLV but returned to baseline levels when TLV was re-established.CONCLUSIONS: RIP has no effects on hemodynamic and respiratory variables in juvenile, healthy piglets. RIP improves the oxygenation after OLV and prevents the decline of exhaled NO after OLV.
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| 47. |
- Bergmann, Astrid, et al.
(author)
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Pulmonary effects of remote ischemic preconditioning in a porcine model of ventilation-induced lung injury
- 2019
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In: Respiratory Physiology & Neurobiology. - : Elsevier. - 1569-9048 .- 1878-1519. ; 259, s. 111-118
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Journal article (peer-reviewed)abstract
- BACKGROUND: One-lung ventilation (OLV) may result in lung injury due to increased mechanical stress and tidal recruitment. As a result, a pulmonary inflammatory response is induced. The present randomized, controlled, animal experiment was undertaken to assess the effects of remote ischemic preconditioning (RIP) on diffuse alveolar damage and immune response after OLV.METHODS: Fourteen piglets (26 ± 2 kg) were randomized to control (n = 7) and RIP group (n = 7). For RIP, a blood pressure cuff at hind limb was inflated up to 200 mmHg for 5 min and deflated for another 5 min, this being done four times before OLV. Mechanical ventilation settings were constant throughout the experiment: VT = 10 ml/kg, FIO2 = 0.40, PEEP = 5cmH2O. OLV was performed by left-sided bronchial blockade. Number of cells was counted from BAL fluid; cytokines were assessed by immunoassays in lung tissue and serum samples. Lung tissue samples were obtained for histological analysis and assessment of diffuse alveolar damage (DAD) score.RESULTS: Hemodynamic and respiratory data were similar in both groups. Likewise, no differences in pulmonary tissue TNF-α and protein content were found, but fewer leukocytes were counted in the ventilated lung after RIP. DAD scores were high without any differences between controls and RIP. On the other hand, alveolar edema and microhemorrhage were significantly increased after RIP.CONCLUSIONS: OLV results in alveolar injury, possibly enhanced by RIP. On the other hand, RIP attenuates the immunological response and decreased alveolar leukocyte recruitment in a porcine model of OLV.
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| 48. |
- Bergmann, Astrid, 1972-
(author)
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Remote Ischemic Preconditioning and its Effects on the Respiratory System
- 2020
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Doctoral thesis (other academic/artistic)abstract
- Mechanical ventilation in itself can lead to pulmonary damage, and one-lung ventilation (OLV), necessary for thoracic surgery, accentuates this injury. Remote ischemic preconditioning (RIP) is a potential tool to reduce lung injury after mechanical ventilation, including OLV. However, current data on pulmonary RIP-effects are contradictory. Therefore, the overall purpose of this Ph.D. project was to assess the effects of RIP on the respiratory system. In Study I, in healthy spontaneously breathing volunteers, oxygenation was impaired early after RIP, which was possibly induced by transient ventilation-perfusion inequality. Studies II, III, and IV were performed in a porcine OLV model. In Study II, we found that RIP possibly enhances alveolar injury, but attenuates the immune response. In Study III, we confirmed that an immune response to RIP takes place, which shows a different time pattern in each cytokine, depending on the site of measurement as well. In Study IV, we studied the porcine model for eight hours and found that RIP improved oxygenation after two hours of OLV and impeded the decline of exhaled nitric oxide (NO) during and after OLV. These findings indicate that RIP mitigates hypoxic pulmonary vasoconstriction (HPV).In summary, RIP has a complex effect on the respiratory system, which partly explains the previous contradictory findings.
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| 49. |
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| 50. |
- Bergquist, Maria, et al.
(author)
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Altered adrenal and gonadal steroids biosynthesis in patients with burn injury
- 2016
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In: Clinical Mass Spectrometry. - : Elsevier BV. - 2213-8005 .- 2376-9998. ; 1, s. 19-26
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Journal article (peer-reviewed)abstract
- Introduction: Burn injury inevitably leads to changes in the endogenous production of cytokines, as well as adrenal and gonadal steroids. Previous studies have reported gender-related differences in outcome following burn injury, which suggests that gonadal steroids may play a role. The aim of this study was to assess alterations in concentration of endogenous steroids in patients with burn injury.Methods: For this single-center, prospective descriptive study, high-sensitivity liquid chromatography tandem mass spectrometry (LC-MS/MS)-based steroid quantification was used to determine longitudinal profiles of the concentrations of endogenous steroids in plasma from sixteen adult male patients with burn injury (14.5-72% of total body surface area). Steroids were extracted from plasma samples and analyzed using multiple reaction monitoring acquisition, with electrospray ionization on a triple quadruple mass spectrometer. Total protein concentration was measured in the samples using spectrophotometry.Results: Steroid and total protein concentration distributions were compared to reference intervals characteristic of healthy adult men. Concentrations of the following steroids in plasma of burn injured patients were found to correlate positively to the area of the burn injury: cortisol (r = 0.84), corticosterone (r = 0.73), 11-deoxycortisol (r = 0.72), androstenedione (r = 0.72), 17OH-progesterone (r = 0.68), 17OH-pregnenolone (r = 0.64) and pregnenolone (r = 0.77). Concentrations of testosterone decreased during the acute phase and were up to ten-times lower than reference values for healthy adult men, while concentrations of estrone were elevated. By day 21 after injury, testosterone concentrations were increased in younger, but not older, patients. The highest concentrations of estrone were observed on day 3 after the injury and then declined by day 21 to concentrations comparable to those observed on the day of the injury.Conclusion: Burn injury alters endogenous steroid biosynthesis, with decreased testosterone concentrations and elevated estrone concentrations, during the first 21 days after the injury. Concentrations of glucocorticoids, progestagens and androgen precursors correlated positively with the area of burn injury. The finding of increased estrone following burn injury needs to be confirmed in a larger hypothesis driven study.
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