| 1. |
- Reinsfelt, Björn, et al.
(författare)
-
The effects of isoflurane-induced electroencephalographic burst suppression on cerebral blood flow velocity and cerebral oxygen extraction during cardiopulmonary bypass.
- 2003
-
Ingår i: Anesthesia and analgesia. - 0003-2999. ; 97:5, s. 1246-50
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated the effects of isoflurane-induced burst suppression, monitored with electroencephalography (EEG), on cerebral blood flow velocity (CBFV), cerebral oxygen extraction (COE), and autoregulation in 16 patients undergoing cardiac surgery. The experimental procedure was performed during nonpulsatile cardiopulmonary bypass (CPB) with mild hypothermia (32 degrees C) in fentanyl-anesthestized patients. Middle cerebral artery transcranial Doppler flow velocity, right jugular vein bulb oxygen saturation, and jugular venous pressure (JVP) were continuously measured. Autoregulation was tested during changes in mean arterial blood pressure (MAP) within a range of 40-80 mm Hg, induced by sodium nitroprusside and phenylephrine before (control) and during additional isoflurane administration to an EEG burst-suppression level of 6-9/min. Isoflurane induced a 27% decrease in CBFV (P < 0.05) and a 13% decrease in COE (P < 0.05) compared with control. The slope of the positive relationship between CBFV and cerebral perfusion pressure (CPP = MAP - JVP) was steeper with isoflurane (P < 0.05) compared with control, as was the slope of the negative relationship between CPP and COE (P < 0.05). We conclude that burst-suppression doses of isoflurane decrease CBFV and impair autoregulation of cerebral blood flow during mildly hypothermic CPB. Furthermore, during isoflurane administration, blood flow was in excess relative to oxygen demand, indicating a loss of metabolic autoregulation of flow.
|
|
| 2. |
- Sand Bown, Lena, et al.
(författare)
-
Vasopressin-induced changes in splanchnic blood flow and hepatic and portal venous pressures in liver resection.
- 2016
-
Ingår i: Acta anaesthesiologica Scandinavica. - : Wiley. - 1399-6576 .- 0001-5172. ; 60:5, s. 607-615
-
Tidskriftsartikel (refereegranskat)abstract
- To minimize blood loss during hepatic surgery, various methods are used to reduce pressure and flow within the hepato-splanchnic circulation. In this study, the effect of low- to moderate doses of vasopressin, a potent splanchnic vasoconstrictor, on changes in portal and hepatic venous pressures and splanchnic and hepato-splanchnic blood flows were assessed in elective liver resection surgery.
|
|
| 3. |
- Aljassim, Obaid, et al.
(författare)
-
Doppler-catheter discrepancies in patients with bileaflet mechanical prostheses or bioprostheses in the aortic valve position.
- 2008
-
Ingår i: The American journal of cardiology. - : Elsevier BV. - 1879-1913 .- 0002-9149. ; 102:10, s. 1383-9
-
Tidskriftsartikel (refereegranskat)abstract
- The aims of the present study were to investigate in vivo Doppler-catheter discrepancies in aortic bileaflet mechanical and stented biologic valves and evaluate whether these can be predicted using Doppler echocardiography. Results of in vitro studies of bileaflet mechanical valves suggested overestimation using Doppler gradients. Findings in stented biologic valves were conflicting. Patients who underwent valve replacement with a St. Jude Medical mechanical (n = 14, size 19 to 29) or a St. Jude Medical Biocor (Biocor, n = 13, size 21 to 25) valve were included. Simultaneous continuous Doppler recordings (transesophageal transducer) and left ventricular and aortic pressure measurements were performed using high-fidelity catheters. Gradients after pressure recovery were predicted from Doppler using a validated equation. Doppler overestimated catheter gradients in both the mechanical and Biocor. Mean Doppler catheter differences for the mechanical/Biocor were for mean gradients of 4 +/- 3 (SD; p = 0.002)/6 +/- 4 mm Hg (p = 0.002). There was a strong relation between catheter and Doppler gradients (r = 0.85 to 0.92). Doppler catheter discrepancy as a percentage of the Doppler mean gradient for the mechanical was median 41% (range -30% to 76%) and for the Biocor was median 35% (range -7% to 75%). The catheter-Doppler discrepancy was not significant using the predicted net gradient from Doppler. In conclusion, this was the first in vivo investigation of prosthetic valves using simultaneous Doppler and high-fidelity catheters. Doppler overestimated catheter gradients in both mechanical and stented biologic valves. However, the discrepancy can be predicted considering pressure recovery in the aorta.
|
|
| 4. |
- Bech-Hanssen, Odd, 1956, et al.
(författare)
-
The relative contribution of prosthetic gradients, systemic arterial pressure, and pulse pressure to the left ventricular pressure in patients with aortic prosthetic valves.
- 2011
-
Ingår i: European journal of echocardiography. - : Oxford University Press (OUP). - 1532-2114 .- 1525-2167. ; 12:1, s. 37-45
-
Tidskriftsartikel (refereegranskat)abstract
- AIMS: Aortic valve replacement (AVR) in patients with aortic stenosis reduces the left ventricular (LV) pressure and the LV mass. However, residual LV hypertrophy at follow-up is a common finding with negative prognostic impact. In the present study, we investigate the contribution of the prosthesis (size, type, and gradients) and the load opposed by the arterial system to the mean LV pressure (MLVP). METHODS AND RESULTS: Twenty-five patients with a bileaflet mechanical (n = 12, size 19-27) or stented biological (size 21-25) valve were included. After weaning from bypass, continuous Doppler recordings (transoesophageal transducer) and simultaneous LV and aortic pressure measurements were performed (high-fidelity catheters). The mean prosthesis gradients with catheter or Doppler were moderately correlated to MLVP (R(2) = 0.40 and 0.34, P = 0.002 and <0.0001). In a multiple regression model, the relationship between MLVP and prosthesis gradient, mean blood pressure, and pulse pressure was strong for both mechanical and biological valves. Using catheter prosthesis gradients, we could explain 97% of the variability in MLVP and when using Doppler gradients 91%. CONCLUSION: In the present study of patients with aortic prosthetic valves, we demonstrate the importance of the load opposed by the arterial system for the LV pressure. Our findings suggest that the MLVP can be estimated from easily obtainable Doppler data and blood pressure measurements. In analysing predictors of LV mass regression, morbidity, and mortality following AVR, the equations might be of interest.
|
|
| 5. |
- Fredholm, Martin, 1972, et al.
(författare)
-
Inotropic and lusitropic effects of levosimendan and milrinone assessed by strain echocardiography: A randomised trial
- 2018
-
Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172. ; 62:9, s. 1246-1254
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundWe compared the direct inotropic and lusitropic effects of two inodilators, milrinone and levosimendan in patients after aortic valve replacement for aortic stenosis. MethodsIn this randomised, blinded study, 31 patients with normal LV function, were randomised to either levosimendan (0.1 and 0.2g/kg/min, n=15) or milrinone (0.4 and 0.8g/kg/min, n=16) after aortic valve replacement. The effects on LV performance, LV strain, systolic (SR-S) and early diastolic (SR-E) strain rate were assessed by a pulmonary artery catheter and transoesophageal two-dimensional speckle tracking echocardiography of the LV inferior wall. To circumvent the inodilator-induced hemodynamic changes on LV systolic and diastolic deformation, central venous pressure (CVP), systolic artery pressure (SAP), and heart rate were maintained constant by colloid infusion, phenylephrine-induced vasoconstriction and atrial pacing, respectively, during drug infusion. ResultsBoth inotropic agents induced a dose-dependent increase in cardiac index and stroke volume index by approximately 20% at the highest infusion rates with no differences between groups (P=.139 and .249, respectively). CVP, pulmonary capillary wedge pressure, SAP and heart rate were maintained constant in both groups. LV strain and SR-S increased with both agents, dose-dependently, by 17%-18% and 25%-30%, respectively, at the highest infusion rates, with no difference between groups (P=.434 and .284, respectively). Both agents improved early LV relaxation with no differences between groups (P=.637). At the higher doses, both agents increased SR-E by 30%. ConclusionsAt clinically relevant infusion rates and a certain increase in LV performance the direct inotropic and lusitropic of milrinone and levosimendan were comparable.
|
|
| 6. |
- Fredholm, Martin, 1972, et al.
(författare)
-
Levosimendan or milrinone for right ventricular inotropic treatment?-A secondary analysis of a randomized trial
- 2020
-
Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 64:2, s. 193-201
-
Tidskriftsartikel (refereegranskat)abstract
- Background The aim of the present study was to compare the effects of milrinone and levosimendan on right ventricular (RV) inotropy and lusitropy in patients after aortic valve replacement (AVR) for aortic stenosis, a procedure in which an abnormal postoperative RV function may be seen. Methods In a prospective, blinded trial, 31 patients were randomized to receive either milrinone (0.4 and 0.8 µg/kg/min, n = 16) or levosimendan (0.1 and 0.2 µg/kg/min, n = 15) after AVR for aortic stenosis. RV performance, afterload (pulmonary arterial elastance), RV strain, systolic (SR‐S) and early diastolic (SR‐E) strain rate were measured by pulmonary artery thermodilution catheterization and transoesophageal two‐dimensional speckle tracking echocardiography. To circumvent the indirect effects of inodilator‐induced hemodynamic changes on RV systolic and diastolic deformation, pulmonary arterial elastance, central venous pressure and heart rate were maintained constant by atrial pacing, plasma volume expansion with colloids and phenylephrine‐induced vasoconstriction during treatment with the inotropes. Results A dose‐dependent increase in stroke volume index and cardiac index by approximately 20% were seen with both agents at the highest doses, with no difference between groups (P = .792 and 0.744, respectively). In both groups, RV strain and SR‐S dose‐dependently increased by 20% and 15%‐19%, respectively, at the highest doses (P = .742 and 0.259, respectively) with no difference between groups. SR‐E improved by both agents 20%‐24% at the highest dose with no difference between groups (P = .714). Conclusions The direct RV inotropic and lusitropic effects of levosimendan and milrinone were comparable at clinically relevant infusion rates.
|
|
| 7. |
- Fredholm, Martin, 1972, et al.
(författare)
-
Load-dependence of myocardial deformation variables - a clinical strain-echocardiographic study
- 2017
-
Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172. ; 61:9, s. 1155-1165
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe effects of left ventricular (LV) loading on myocardial deformation variables are not well-studied in the clinical setting. In the present study, we evaluated the effects of isolated changes in preload, afterload and heart rate on LV longitudinal strain, systolic (SR-S) and early diastolic strain rate (SR-E) in post-cardiac surgery patients. MethodsTwenty-one patients were studied early after cardiac surgery. Longitudinal myocardial strain and SR were analysed off-line using 2-D speckle echocardiography. The experimental protocol consisted of three consecutive interventions: (1) preload was increased by passive leg elevation, (2) afterload was increased by an infusion of phenylephrine to increase arterial blood pressure by 10-15% and (3) heart rate was increased 10% and 20% by atrial pacing. During both the preload and afterload challenges heart rate was kept constant by atrial pacing. Central venous pressure was kept constant during pacing by infusion of hetastarch/albumin. ResultsThe increase in preload increased LV strain, SR-S and SR-E by 20%, 11% and 17%, respectively. The phenylephrine-induced increase in afterload, did not affect LV strain, SR-S or SR-E. LV strain was not affected while SR-S and SR-E increased by pacing-induced heart rate increase. ConclusionAfter cardiac surgery, systolic and early diastolic strain rate are dependent on both preload and heart rate, while neither of these variables was afterload-dependent. LV strain was preload-dependent but not affected by atrial pacing. When evaluating the direct effects of various pharmacological or other interventions on myocardial contractility and relaxation, preload and heart rate must be controlled.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
