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- Almgren, Birgitta, et al.
(författare)
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Post-suction recruitment manoeuvre restores lung function in healthy, anaesthetized pigs
- 2004
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Ingår i: Anaesthesia and Intensive Care. - 0310-057X .- 1448-0271. ; 32:3, s. 339-345:32, s. 339-345
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Tidskriftsartikel (refereegranskat)abstract
- Endotracheal suction can cause partial lung collapse and hypoxia and alter lung mechanics. We investigated the effects of adding a recruitment manoeuvre directly after endotracheal suction to restore lung volume in volume-controlled ventilation and pressure-controlled ventilation modes. Five anaesthetized pigs were investigated. The effects of endotracheal suction with or without a recruitment manoeuvre were compared in random order. In volume-controlled ventilation, compliance decreased after suction from 33 +/- 5 to 26 +/- 6 ml x cmH2O(-1) (P<0.05), and 30 minutes later it remained decreased at 25 +/- 6 ml x cmH2O(-1). Venous admixture increased after suction from 5 +/- 2 to 8 +/- 4% (P<0.05), but had recovered at 30 minutes. In pressure-controlled ventilation, compliance decreased after suction from 34 +/- 3 to 25 +/- 7 ml x cmH2O(-1) (P<0.05), and 30 minutes later it remained decreased at 25 +/- 7 ml x cmH2O(-1). Venous admixture increased after suction from 5 +/- 2 to 13 +/- 7% (P<0.05), and had not recovered after 30 minutes, 10 +/- 4%. When a recruitment manoeuvre was applied directly after suction, no negative side-effects were registered in volume-controlled ventilation or pressure-controlled ventilation. We conclude that the impairment of lung mechanics and gas exchange induced by endotracheal suction can be prevented by a simple post-suction recruitment manoeuvre. Further studies are needed to identify a suitable suction recruitment manoeuvre in patients with diseased lungs.
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| 2. |
- Almgren, Birgitta, et al.
(författare)
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Side effects of endotracheal suction in pressure and volume controlled ventilation
- 2004
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Ingår i: Chest. - : Elsevier BV. - 0012-3692 .- 1931-3543. ; 125:3, s. 1077-1080
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Tidskriftsartikel (refereegranskat)abstract
- STUDY OBJECTIVES:To investigate the effects of endotracheal suction in volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) with an open suction system (OSS) or a closed suction system (CSS).DESIGN:Randomized comparison.SETTING:Animal research laboratory.PATIENTS:Twelve healthy anesthetized pigs.INTERVENTIONS:The effects of endotracheal suction during VCV and PCV with tidal volume (VT) of 14 mL/kg were compared. A 60-mm inner-diameter endotracheal tube was used. Ten-second suction was performed using OSS and CSS with 12F and 14F catheters connected to - 14 kPa vacuum.MEASUREMENTS AND RESULTS:Thirty minutes after suction in PCV, VT was still decreased by 27% (p < 0.001), compliance (Crs) by 28% (p < 0.001), and PaO(2) by 26% (p < 0.001); PaCO(2) was increased by 42% (p < 0.0001) and venous admixture by 158% (p = 0.003). Suction in VCV affected only Crs (decreased by 23%, p < 0.001) and plateau pressure (increased by 24%, p < 0.001). The initial impairment of gas exchange following suction in VCV was no longer statistically significant after 30 min.CONCLUSIONS:In conclusion, endotracheal suction causes lung collapse leading to impaired gas exchange, an effect that is more severe and persistent in PCV than in VCV.
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| 3. |
- Heinonen, Erkki, et al.
(författare)
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Pulsed delivery of nitric oxide counteracts hypoxaemia in the anaesthetized horse
- 2001
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Ingår i: Veterinary Anaesthesia and Analgesia. - : Elsevier BV. - 1467-2987 .- 1467-2995. ; 28:1, s. 3-11
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Tidskriftsartikel (refereegranskat)abstract
- Objective To study the effect of the pulsed delivery of nitric oxide (NO) on pulmonary gas exchange in the anaesthetized horses.Design Prospective, controlled randomized.Animals Five healthy Standardbred trotters, three geldings and two mares.Methods The horses were anaesthetized with thiopentone and isoflurane and positioned in dorsal recumbency. Nitric oxide was added as a pulse to the inspired gas during the first half of each inspiration. In three horses the effect of NO on the ventilation–perfusion distribution was also investigated using the multiple inert gas elimination technique. Data were analysed with repeated measures ANOVA.Results During spontaneous breathing, arterial oxygen tension (PaO2) increased with NO inhalation, from 14 ± 2 to 29 ± 3 kPa (105 ± 15 to 218 ± 23 mm Hg) (p < 0.001). Arterial oxygen tension also increased, from 17 ± 3 to 31 ± 5 kPa (128 ± 23 to 233 ± 38 mm Hg) (p < 0.05) during intermittent positive pressure ventilation. The increase in PaO2 was mainly due to a reduced right to left vascular shunt, but ventilation and perfusion matching also improved. The beneficial effect of NO inhalation was lost within 5 minutes of its discontinuation.Conclusion Delivery of NO as a pulse during inspiration is an effective method for counteracting impaired gas exchange caused by anaesthesia in horses. Pulsation has to be continuous because of the transience of NO's therapeutic effect.Clinical relevance Horses with impaired pulmonary gas exchange during anaesthesia can be treated with pulsed NO inhalation.
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| 8. |
- Perchiazzi, G, et al.
(författare)
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Assessment of respiratory system mechanics by artificial neural networks: an exploratory study.
- 2001
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Ingår i: Journal of applied physiology (Bethesda, Md. : 1985). - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 90:5, s. 1817-24
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Tidskriftsartikel (refereegranskat)abstract
- We evaluated 1) the performance of an artificial neural network (ANN)-based technology in assessing the respiratory system resistance (Rrs) and compliance (Crs) in a porcine model of acute lung injury and 2) the possibility of using, for ANN training, signals coming from an electrical analog (EA) of the lung. Two differently experienced ANNs were compared. One ANN (ANN(BIO)) was trained on tracings recorded at different time points after the administration of oleic acid in 10 anesthetized and paralyzed pigs during constant-flow mechanical ventilation. A second ANN (ANN(MOD)) was trained on EA simulations. Both ANNs were evaluated prospectively on data coming from four different pigs. Linear regression between ANN output and manually computed mechanics showed a regression coefficient (R) of 0.98 for both ANNs in assessing Crs. On Rrs, ANN(BIO) showed a performance expressed by R = 0.40 and ANN(MOD) by R = 0.61. These results suggest that ANNs can learn to assess the respiratory system mechanics during mechanical ventilation but that the assessment of resistance and compliance by ANNs may require different approaches.
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| 9. |
- Rylander, Christian, 1960, et al.
(författare)
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Functional residual capacity and respiratory mechanics as indicators of aeration and collapse in experimental lung injury.
- 2004
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Ingår i: Anesthesia and analgesia. - 0003-2999. ; 98:3
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Tidskriftsartikel (refereegranskat)abstract
- Increased functional residual capacity (FRC) and compliance are two desirable, but seldom measured, effects of positive end-expiratory pressure (PEEP) in mechanically ventilated patients. To assess how these variables reflect the morphological lung perturbations during the evolution of acute lung injury and the morphological changes from altered PEEP, we correlated measurements of FRC and respiratory system mechanics to the degree of lung aeration and consolidation on computed tomography (CT). We used a porcine oleic acid model with FRC determinations by sulfur hexafluoride washin-washout and respiratory system mechanics measured during an inspiratory hold maneuver. Within the first hour, during constant volume-controlled ventilation with PEEP 5 cm H(2)O, FRC decreased by 45% +/- 15% (P = 0.005) and compliance decreased by 35% +/- 12% (P = 0.005). Resistance increased by 60% +/- 62% (P = 0.005). Only the FRC changes correlated significantly to the decreased aeration (R(2) = 0.56; P = 0.01) and the increased consolidation (R(2) = 0.43; P = 0.04) on CT. When the PEEP was changed to either 10 or 0 cm H(2)O, there were larger changes in FRC than in compliance. We conclude that, in our model, FRC was a more sensitive indicator of PEEP-induced aeration and recruitment of lung tissue and that FRC may be a useful adjunct to PaO(2) monitoring. IMPLICATIONS: Lung injury was quantified on computed tomography and related to monitored values of functional residual capacity and mechanical properties of the respiratory system. We found the functional residual capacity to be a more sensitive marker of the lung perturbations than the compliance. It might be of value to include functional residual capacity in the monitoring of acute lung injury.
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