| 1. |
- 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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| 2. |
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| 3. |
- Choncholas, Gary, et al.
(författare)
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Validation and clinical application of a first order step response equation for nitrogen clearance during FRC measurement.
- 2008
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Ingår i: Journal of clinical monitoring and computing. - : Springer Science and Business Media LLC. - 1387-1307 .- 1573-2614. ; 22:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To derive a difference equation based on mass conservation and on alveolar tidal volumes for the calculation of Functional Residual Capacity. Derive an equation for the FRC from the difference equation. Furthermore, to derive and validate a step response equation as a solution of the difference equation within the framework of digital signal processing where the FRC is known a priori. METHODS: A difference equation for the calculation of Functional Residual Capacity is derived and solved as step response of a first order system. The step response equation calculates endtidal fractions of nitrogen during multiple breath nitrogen clearance. The step response equation contains the eigenvalue defined as the ratio of FRC to the sum of FRC and alveolar tidal ventilation. Agreement of calculated nitrogen fractions with measured fractions is demonstrated with data from a metabolic lung model, measurements from patients in positive pressure ventilation and volunteers breathing spontaneously. Examples of eigenvalue are given and compared between diseased and healthy lungs and between ventilatory settings. RESULTS: Comparison of calculated and measured fractions of endtidal nitrogen demonstrates a high degree of agreement in terms of regression and bias and limits of agreement (precision) in Bland & Altman analysis. Examples illustrate the use of the eigenvalue as a possible discriminator between disease states. CONCLUSION: The first order step response equation reliably calculates endtidal fractions of nitrogen during washout based on a Functional Residual Capacity. The eigenvalue may be a clinically valuable index alone or in conjunction with other indices in the analysis of respiratory states and may aid in the setting of the ventilator.
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| 4. |
- Grubb, Tamara L, et al.
(författare)
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Physiologic responses and plasma endothelin-1 concentrations associated with abrupt cessation of nitric oxide inhalation in isoflurane-anesthetized horses
- 2008
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Ingår i: American Journal of Veterinary Research. - : American Veterinary Medical Association (AVMA). - 0002-9645 .- 1943-5681. ; 69:3, s. 423-430
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To assess physiologic responses and plasma endothelin (ET)-1 concentrations associated with abrupt cessation of nitric oxide (NO) inhalation in isoflurane-anesthetized horses. ANIMALS: 6 healthy adult Standardbreds. PROCEDURES: Horses were anesthetized with isoflurane in oxygen and placed in dorsal recumbency. Nitric oxide was pulsed into the respiratory tract for 2.5 hours, and then administration was abruptly discontinued. Just prior to commencement and at cessation of NO administration, and at intervals during a 30-minute period following cessation of NO inhalation, several variables including PaO(2), mean pulmonary artery pressure, venous admixture or pulmonary shunt fraction (Qs/Qt), and plasma ET-1 concentration were recorded or calculated. RESULTS: After cessation of NO inhalation, PaO(2) decreased slowly but significantly (172.7 +/- 29.8 mm Hg to 84.6 +/- 10.9 mm Hg) and Qs/Qt increased slowly but significantly (25 +/- 2% to 40 +/- 3%) over a 30-minute period. Mean pulmonary artery pressure increased slightly (14.0 +/- 1.3 mm Hg to 16.8 +/- 1 mm Hg) over the same time period. No change in serum ET-1 concentration was detected, and other variables did not change or underwent minor changes. CONCLUSIONS AND CLINICAL RELEVANCE: The improvement in arterial oxygenation during pulsed inhalation of NO to healthy isoflurane-anesthetized horses decreased only gradually during a 30-minute period following cessation of NO inhalation, and serum ET-1 concentration was not affected. Because a rapid rebound response did not develop, inhalation of NO might be clinically useful in the treatment of hypoxemia in healthy isoflurane-anesthetized horses.
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| 5. |
- 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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| 7. |
- Heinonen, Erkki, 1958-
(författare)
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Synchronized delivery of inspired nitric oxide : Effects on oxygenation and pulmonary tension during artificial ventilation
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nitric oxide (NO) is a mediator of vascular smooth muscle tension that metabolises rapidly in blood. NO delivered by inhalation can therefore be used as a selective pulmonary vasodilator to relieve pulmonary hypertension or to improve oxygenation with no systemic effects. In artificial ventilation nitric oxide has been administered in inspiration gas as a continuous gas flow or to form constant inspired concentration. Homogeneous inspired gas mixture has been regarded essential for successful therapy and the therapy has been characterized by the mixture NO concentration. The response in oxygenation on NO therapy has, however, been variable. Administration of NO as a short pulse synchronously with inspiration has been suggested to improve the response. In this study the NO administration was examined theoretically and experimentally with the aim to relieve pulmonary hypertension and improve oxygenation during artificial ventilation. For the experimental study a system for the synchronized administration was developed.The effect on oxygenation was studied during equine anaesthesia where hypoxemia develops regularly secondary to left-to-right shunt caused by atelectasis. By administering the NO as a short pulse in early inspiration to well ventilated lung areas the oxygenation could be effectively improved. Delayed administration to low ventilated lung areas was found possible for a negative contribution on oxygenation, which reduces the improvement gained in the well-ventilated lung areas. When NO is delivered into the whole inspiration, the net effect on oxygenation is the sum of these negative and positive contributions, whereas with pulsed delivery to the early inspiration the negative contribution can be avoided. This finding may be the main explanation for the varying response in oxygenation detected in patients as a response to NO inhalation.When the NO therapy aimed for the relief of induced pulmonary hypertension in pigs, no difference was observed between NO delivery as a short pulse or given to the whole inspiration. Maximum vasodilatation was observed with 105 nmol/min delivery rate. A larger delivery rate only contributed to an abrupt increase in pulmonary pressure at cessation of the delivery.The NO uptake from alveoli to tissue depends on the alveolar NO partial pressure. In a simulation this partial pressure was shown to be independent of the administration mode. Also the relationship between the NO uptake and delivery setting was not explicit. With pulsed delivery, expired NO can be reduced which was confirmed by the experimental results. This is important when the NO therapy is given in rebreathing circuit.
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| 8. |
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| 9. |
- Nyman, Görel, et al.
(författare)
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Pulsed delivery of inhaled nitric oxide counteracts hypoxaemia during 2.5 hours of inhalation anaesthesia in dorsally recumbent horses
- 2012
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Ingår i: Veterinary Anaesthesia and Analgesia. - : Elsevier BV. - 1467-2987 .- 1467-2995. ; 39:5, s. 480-487
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Tidskriftsartikel (refereegranskat)abstract
- Objective The study aimed to investigate the effect of varying pulse lengths of inhaled nitric oxide (iNO), and 2.5 hours of continuous pulse-delivered iNO on pulmonary gas exchange in anaesthetized horses.Study Design Experimental study. Animals Six Standardbred horses.Methods Horses received acepromazine, detomidine, guaifenesin, thiopentone and isoflurane in oxygen, were positioned in dorsal recumbency and were breathing spontaneously. iNO was on average pulsed during the first 20, 30, 43 or 73% of the inspiration in 15 minute steps. The pulse length that corresponded to the highest (peak) partial pressure of arterial oxygen (PaO2) in the individual horses was determined and delivered for a further 1.5 hours. Data measured or calculated included arterial and mixed venous partial pressures of O2 and CO2, heart rate, respiratory rate, expired minute ventilation, pulmonary and systemic arterial mean pressures, cardiac output and venous admixture. Data (mean +/- SD) was analysed using anova with p < 0.05 considered significant.Results Although the pulse length of iNO that corresponded to peak PaO2 varied between horses, administration of all pulse lengths of iNO increased PaO2 compared to baseline. The shortest pulse lengths that resulted in the peak PaO2 were 30 and 43% of the inspiration. Administration of iNO increased PaO2 (12.6 +/- 4.1 kPa [95 +/- 31 mmHg] at baseline to a range of 23.0 +/- 8.4 to 25.3 +/- 9.0 kPa [173 to 190 mmHg]) and PaCO2 (8.5 +/- 1.2 kPa [64 +/- 9 mmHg] to 9.8 +/- 1.5 kPa [73 +/- 11 mmHg]) and decreased venous admixture from 32 +/- 6% to 25 +/- 6%. The increase in PaO2 and decrease in venous admixture was sustained for the entire 2.5 hours of iNO delivery.Conclusions The improvement in arterial oxygenation during pulsed delivery of iNO was significant and sustained throughout 2.5 hours of anaesthesia.Clinical relevance Pulsed iNO potentially could be used clinically to counteract hypoxemia in anaesthetized horses.
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| 10. |
- Oddli, Hanne Weie, et al.
(författare)
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Learning Processes and Acquisition of Knowledge and Skills in Training and Supervision of Psychotherapy and Counselling : A Study Protocol for a Scoping Review
- 2021
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Ingår i: Frontiers in Psychology. - : Frontiers Media SA. - 1664-1078. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Increased awareness of the individual therapist’s vital contribution to treatment processes and outcome, and the potential role of training and supervision in this respect, warrants a close look at the empirical and theoretical literature on teaching and learning of therapists and counselors.Methods: A scoping review of the literature will be conducted based on an overarching research question: when authors have reported on learning processes and acquisition of knowledge and skills in psychotherapy/counseling and supervision/training literature over the past 30 years (since 1990), what evidence, concepts, theories, and models have they reported? A comprehensive search strategy is carried out to identify publications indexed in Scopus, PsycINFO, and Cochrane Central Register of Controlled Trials. Publications will be sorted according to four categories: (1) conceptual/theoretical; (2) empirical (quantitative, qualitative, mixed methods); (3) review, meta-synthesis or -analysis; (4) training program/model description. Procedures for the upcoming scoping review of conceptual/theoretical, empirical, and training program/model description publications will be outlined.Conclusion: Besides clarifying existing perspectives, practices, and evidence, and documenting the shifting trends of the field during the past three decades, this scoping review identifies knowledge gaps that point to vital future directions for research and theory development. Moreover, the comprehensive scoping lays the foundation for subsequent, more focused systematic reviews that address identified key research topics more specifically.
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