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| 2. |
- Andersson-Wenckert, Ingrid, et al.
(författare)
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Anevac-D, a new system for close scavenging of anesthetic gases in dental practice
- 1989
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Ingår i: Scandinavian Journal of Dental Research. - 0029-845X. ; 97:5, s. 456-64
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Tidskriftsartikel (refereegranskat)abstract
- Anevac-D, a new system for close scavenging of anesthetic gases in dental practice is described. It consists of a rubber nose mask surrounded by an outer rigid shell and a chin scavenger. A vacuum in the slot between the nose masks provides scavenging of gases escaping from the inner mask. Gases escaping from the mouth are evacuated mainly by the skin scavenger. The efficiency of this system was assessed in healthy volunteers using argon as a tracer gas. Mass spectrometry was used for measurement of inspired, expired, and scavenged gas concentrations. The scavenging efficiency of the complete system was around 80% and was not affected by poor patient cooperation. It decreased to about 65% when the chin scavenger was removed. The dentist's exposure was measured by sampling of argon in the breathing zone by a Saran system. The average 4-min exposure varied between 90 and 250 ppm depending on system configuration and patient cooperation. Patient acceptance and clinical applicability were judged good. It is concluded that the Anevac-D system provides excellent scavenging properties and exposure levels well within the official recommendations by the Swedish Board of Occupational Safety and Health.
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| 3. |
- Axelsson, Birger, 1957-, et al.
(författare)
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Effects of Combined Milrinone and Levosimendan Treatment on Systolic and Diastolic Function During Postischemic Myocardial Dysfunction in a Porcine Model
- 2016
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Ingår i: Journal of Cardiovascular Pharmacology and Therapeutics. - Thousand Oaks, USA : Sage Publications. - 1074-2484 .- 1940-4034. ; 21:5, s. 495-503
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Tidskriftsartikel (refereegranskat)abstract
- It is not known whether there are positive or negative interactions on ventricular function when a calcium-sensitizing inotrope is added to a phosphodiesterase inhibitor in the clinical setting of acute left ventricular (LV) dysfunction. We hypothesized that when levosimendan is added to milrinone treatment, there will be synergetic inotropic and lusitropic effects. This was tested in an anesthetized porcine postischemic global LV injury model, where ventricular pressures and volumes (conductance volumetry) were measured. A global ischemic injury was induced by repetitive left main stem coronary artery occlusions. Load-independent indices of LV function were assessed before and after ventricular injury, after milrinone treatment, and finally after addition of levosimendan to the milrinone treatment. Nonparametric, within-group comparisons were made. The protocol was completed in 12 pigs, 7 of which received the inotrope treatment and 5 of which served as controls. Milrinone led to positive lusitropic effects seen by improvement in tau after myocardial stunning. The addition of levosimendan to milrinone further increased lusitropic state. The latter effect could however not be attributed solely to levosimendan, since lusitropic state also improved spontaneously in time-matched controls at the same rate during the corresponding period. When levosimendan was added to milrinone infusion, there was no increase in systolic function (preload recruitable stroke work) compared to milrinone treatment alone. We conclude that in this model of postischemic LV dysfunction, there appears to be no clear improvement in systolic or diastolic function after addition of levosimendan to established milrinone treatment but also no negative effects of levosimendan in this context.
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| 4. |
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| 5. |
- Broome, M., et al.
(författare)
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Acute effects of angiotensin II on myocardial performance
- 2001
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 45:9, s. 1147-54
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Specific angiotensin II (Ang II) receptors exist in many organs including peripheral blood vessels, cardiac myocytes and the central nervous system. This suggests multiple sites of actions for Ang II throughout the cardiovascular system. Cardiac effects of Ang II are not completely understood, though its prominent vasoconstrictor actions are well described. This study was designed to assess left ventricular function during administration of Ang II using relatively load-independent methods in a whole-animal model. METHODS: Ang II was infused in incremental doses (0-200 microg x h(-1)) in anaesthetised instrumented pigs (n=10). Cardiac systolic and diastolic function were evaluated by analysis of the left ventricular pressure-volume relationship. RESULTS: Heart rate (HR), mean arterial pressure (MAP) and systemic vascular resistance (SVR) increased dose-dependently with Ang II, while cardiac output (CO) remained unchanged. Systolic function indices, end-systolic elastance (Ees) and preload recruitable stroke work (PRSW), demonstrated dose-dependent increases. The diastolic function parameter tau (tau) did not change with increasing Ang II dose. CONCLUSION: Ang II infusion caused increases in contractility indices in anaesthetised pigs in the doses used in this study. The mechanisms for these systolic function effects may be a direct myocardial effect or modulated through changes in autonomic nervous system activity.
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| 6. |
- Broome, M., et al.
(författare)
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Angiotensin II mesenteric and renal vasoregulation : dissimilar modulatory effects with nitroprusside
- 2000
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 44:10, s. 1238-45
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The role of systemic arterial pressure for the vascular effects of angiotensin II (Ang II) and the interactions between Ang II and perfusion pressure-dependent local vascular control mechanisms are not well understood. This study addresses these aspects of exogenous Ang II in the mesenteric and renal regional circulations. METHODS: Ang II was infused in incremental doses (0-200 microg/h) in anesthetized instrumented pigs (n=10). Renal and portal blood flows were measured by perivascular ultrasound. In the second part of the study, sodium nitroprusside (SNP) was infused at doses titrated to keep mean arterial pressure constant, in spite of concurrent Ang II administration. RESULTS: Powerful dose-dependent vasoconstrictions by Ang II were found in renal and mesenteric vascular beds (at highest Ang II doses vascular resistances increased by 109% and 88% respectively). Ang II-induced vasoconstriction was fully inhibited in the mesenteric, but not in the renal circulation, during conditions of constant mean arterial pressures achieved by SNP infusion. CONCLUSIONS: Mesenteric, but not renal, vasoconstriction by Ang II was inhibited by pharmacological maintenance of perfusion pressure. This could reflect differences between these vascular beds as regards the importance of co-acting myogenic pressure-dependent vasoconstriction. Alternatively, as the drug chosen for pressure control, sodium nitroprusside, serves as a nitric oxide donor, the relative balance between nitric oxide-mediated vasodilation and Ang II-induced vasoconstriction could have regional differences.
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| 7. |
- Broomé, Michael, et al.
(författare)
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Pressure-independent cardiac effects of angiotensin II in pigs.
- 2004
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Ingår i: Acta Anaesthesiol Scand. - 0001-6772 .- 1365-201X. ; 182:2, s. 111-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Angiotensin II (Ang II) is a potent vasoconstrictor with an important role in the development of cardiovascular disease. Earlier results have shown a positive acute inotropic effect of Ang II in anaesthetized pigs together with significant vasoconstriction. This investigation was designed to study cardiac effects of Ang II, when blood pressure was maintained constant by experimental means. METHODS: Ang II (200 microg h(-1)) was infused in anaesthetized pigs (n = 10) at two different arterial blood pressures, the first determined by the effects of Ang II alone, and the second maintained at baseline blood pressure with nitroprusside. Cardiac systolic and diastolic function was evaluated by analysis of left ventricular pressure-volume relationships. RESULTS: Heart rate, end-systolic elastance (Ees) and pre-load adjusted maximal power (PWRmax EDV(-2)) increased at both blood pressure levels, although less when blood pressure was kept constant with nitroprusside. The time constant for isovolumetric relaxation (tau(1/2)) was prolonged with Ang II alone and shortened with Ang II infused together with nitroprusside. CONCLUSION: Ang II infusion in the pig has inotropic and chronotropic properties independent of arterial blood pressure levels, although the effects seem to be blunted by pharmacological actions of the nitric oxide donor nitroprusside.
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| 8. |
- Broome, M., et al.
(författare)
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The cardiac effects of intracoronary angiotensin II infusion
- 2002
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Ingår i: Anesthesia and Analgesia. - : Ovid Technologies (Wolters Kluwer Health). - 0003-2999 .- 1526-7598. ; 94:4, s. 787-93, table of contents
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Tidskriftsartikel (refereegranskat)abstract
- Angiotensin II (Ang II) is a potent vasoconstrictor, which recently has been shown to also have significant inotropic effects. Previous results regarding the mechanisms of the acute inotropic effects of Ang II are not conclusive. We designed this study to investigate the local cardiac effects of intracoronary Ang II infusion in doses not affecting systemic circulation. Ang II (2.5-40 microg/h) was infused in the left coronary artery of Yorkshire pigs (n = 9) reaching calculated intracoronary Ang II concentrations of 842 +/- 310, 3342 +/- 1238, and 12448 +/- 4393 pg/mL, respectively. Cardiac systolic and diastolic function was evaluated by analysis of the left ventricular pressure-volume relationship. Coronary flow was measured by using a coronary sinus catheter and the retrograde thermodilution technique. No significant changes were seen in the systolic and diastolic function variables of heart rate, end-systolic elastance, preload recruitable stroke work, the time constant for isovolumetric relaxation, or in coronary vascular resistance and flow. The positive inotropic and chronotropic effects of Ang II seen in previous studies seem thus to be mediated via extracardiac actions of Ang II. Coronary vascular tone is not affected by local Ang II infusion in anesthetized pigs. IMPLICATIONS: The positive inotropic and chronotropic effects of angiotension II (Ang II) seen in previous studies seem to be mediated via extracardiac actions of Ang II. Coronary vascular tone is not affected by local Ang II infusion in anesthetized pigs.
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| 9. |
- Haney, Michael, et al.
(författare)
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Analysis of left ventricular systolic function during elevated external cardiac pressures : an examination of measured transmural left ventricular pressure during pressure-volume analysis
- 2001
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Ingår i: Acta Anaesthesiol Scand. ; 45:7, s. 868-74
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Variations or disturbances in intrathoracic and extracardiac pressures (ECP) occur in critically ill and anaesthetised patients. There are uncertainties concerning the analysis of left ventricular pressure-volume relationship (LVPVR) and the calculation of systolic function parameters when conducted without reference to transmural left ventricular pressure (LVPtm) in the setting of elevated ECP. METHODS: In 7 anaesthetised adult pigs, we measured LVPVR using conductance volumetry and tip manometry along with measurement of pericardial and other intrathoracic pressures. Experimental pericardial infusion and pleural insufflation were performed. Transient controlled preload reductions were accomplished using balloon occlusion of the inferior vena cava. Preload recruitable stroke work (PRSW) was calculated using both intracavitary left ventricular pressure (LVPic) and LVPtm, and differences were tested for using a paired t-test. RESULTS: The pericardial and pleural interventions produced significant elevations in ECP. No difference in PRSW calculated using LVPic and LVPtm was detected. CONCLUSION: These results suggest that LVPtm need not be measured and included in LVPVR analysis of systolic function when there is significant external cardiac pressure. To be able to employ LVPVR analysis of systolic function without reference to LVPtm is important for simplified application in the clinical setting, particularly when elevated extracardiac pressures are suspected, or have been therapeutically induced, as with continuous positive pressure ventilation.
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| 10. |
- Haney, Michael F, et al.
(författare)
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Myocardial systolic function increases during positive pressure lung inflation.
- 2005
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Ingår i: Anesth Analg. - 0003-2999. ; 101:5, s. 1269-74
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Tidskriftsartikel (refereegranskat)abstract
- Lung inflation with positive airway pressure may have rapid and dynamic effects on myocardial contractile function. We designed this study to assess the magnitude and time to onset of myocardial function changes during the initiation of single positive pressure lung inflation at clinically relevant inflation pressures. In 8 anesthetized 40-kg pigs, left ventricular pressures and volumes were measured directly (conductance volumetry). A 15 cm H2O airway pressure plateau with lung inflation (PPLI-15) was performed, and 2 single beats from that sequence, one from resting apnea at zero airway pressure and the second from the point when the lungs were first maximally inflated, were selected for analysis. Systolic function variables for zero airway pressure and PPLI-15 were analyzed. Systolic elastance, derived from bilinear time-varying elastance curves, increased approximately 15% during PPLI-15 from zero airway pressure. This agreed with other systolic function variables that identified an increase in left ventricular contractile function for the lung inflation beat. Serial measurements of myocardial function should be conducted with constant airway pressure and lung inflation conditions.
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