| 1. |
- Aljassim, Obaid, et al.
(author)
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Doppler-catheter discrepancies in patients with bileaflet mechanical prostheses or bioprostheses in the aortic valve position.
- 2008
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In: The American journal of cardiology. - : Elsevier BV. - 1879-1913 .- 0002-9149. ; 102:10, s. 1383-9
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Journal article (peer-reviewed)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.
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| 2. |
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| 3. |
- Jörgensen, Kirsten, 1959, et al.
(author)
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Effects of levosimendan on left ventricular relaxation and early filling at maintained preload and afterload conditions after aortic valve replacement for aortic stenosis.
- 2008
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In: Circulation. - 1524-4539. ; 117:8, s. 1075-81
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Journal article (peer-reviewed)abstract
- BACKGROUND: We determined the effects of levosimendan, a calcium sensitizer, on left ventricular (LV) diastolic function in patients with LV hypertrophy. METHODS AND RESULTS: In this prospective, randomized, blinded study, 23 patients received either levosimendan (0.1 and 0.2 microg x kg(-1) x min(-1); n=12) or placebo (n=11) after aortic valve replacement for aortic stenosis. The effects on LV performance, dimensions, filling patterns, and isovolumic relaxation time, as well as systemic hemodynamics, were assessed by pulmonary artery thermodilution catheterization and transesophageal 2-dimensional Doppler echocardiography. To circumvent the confounding effects of the levosimendan-induced hemodynamic changes on Doppler echocardiographic indexes of LV early relaxation, heart rate and mean arterial and central venous pressures were kept constant during levosimendan/placebo infusion by atrial pacing, vasopressor, and colloid infusions. In the levosimendan group, dose-dependent increases in cardiac output (28%; P<0.001) and stroke volume (26%; P<0.001) and a decrease in systemic vascular resistance (-22%; P<0.001) were observed. There was a trend for an increase in LV ejection fraction (12%; P=0.058) with levosimendan. There were no significant differences in systolic, diastolic arterial, or LV filling pressures or LV end-diastolic area between the 2 groups. Isovolumic relaxation time decreased (-23%; P<0.001), as did the deceleration slope of early diastolic filling (-45%; P<0.01), whereas peak early diastolic filling velocity (16%, P<0.01) and peak late diastolic filling velocity (15%; P<0.001) increased after levosimendan compared with placebo. CONCLUSIONS: Levosimendan, in addition to its inotropic effects, exerts a direct positive lusitropic effect in patients with LV hypertrophy as it shortens isovolumic relaxation time and improves LV filling.
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| 4. |
- Jörgensen, Kirsten, 1959, et al.
(author)
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Left ventricular performance and dimensions in patients with severe emphysema.
- 2007
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In: Anesthesia and analgesia. - : Ovid Technologies (Wolters Kluwer Health). - 1526-7598 .- 0003-2999. ; 104:4, s. 887-92
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Journal article (peer-reviewed)abstract
- BACKGROUND: Concomitant heart dysfunction during the course of chronic obstructive pulmonary disease is well recognized. The prevailing view is that mainly the right side of the heart is involved. We evaluated left ventricular (LV) function and dimensions in patients with severe emphysema. METHODS: Patients with severe emphysema undergoing lung volume reduction surgery were studied after anesthesia induction (n = 10). Non-emphysematous patients scheduled for lobectomy served as controls (n = 10). LV dimensions were measured with patients in the supine position by transesophageal two-dimensional echocardiography and systemic hemodynamics by a pulmonary artery thermodilution catheter, before and during central blood volume expansion by passive leg elevation. RESULTS: Baseline cardiac index (-25%), stroke volume index (SVI, -32%) stroke work index (-34%) and LV end-diastolic area index (EDAI, -33%) were significantly (P < 0.001) lower in the emphysema group. Passive leg elevation increased SVI and LV area ejection fraction more in the emphysema group than in controls (P < 0.05). The DeltaSVI/Delta pulmonary capillary wedge pressure and the DeltaSVI/DeltaEDAI relationships were significantly (P < 0.05) higher in the emphysema group compared to controls (2.2 +/- 0.71 vs 0.6 +/- 0.2 mL/mm Hg x m2 and 5.8 +/- 0.89 vs 2.8 +/- 0.8 mL/cm2 x m2, respectively). Preload-recruitable stroke work (Deltastroke work index/DeltaEDAI), a load-independent index of systolic LV function, did not differ between the two groups. CONCLUSION: The LV in patients with severe emphysema is hypovolemic, and operates on a steeper portion of the LV function curve, while indices of systolic function are not significantly impaired compared to non-emphysematous controls.
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| 5. |
- Jörgensen, Kirsten, 1959, et al.
(author)
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Reduced intrathoracic blood volume and left and right ventricular dimensions in patients with severe emphysema: an MRI study.
- 2007
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In: Chest. - : Elsevier BV. - 0012-3692. ; 131:4, s. 1050-7
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Journal article (peer-reviewed)abstract
- BACKGROUND: Left ventricular (LV) filling is impaired in patients with severe emphysema manifesting in small end-diastolic dimensions. We hypothesized that the hyperinflated lungs of these patients with high intrinsic positive end-expiratory pressure will decrease intrathoracic blood volume (ITBV) and ventricular preload. We therefore measured ITBV, and LV and right ventricular (RV) dimensions and function using MRI techniques in patients with severe emphysema. METHODS: Patients with severe emphysema (n = 13) and matched healthy volunteers (n = 11) were included. The magnetic resonance (MR) examination consisted of three parts: (1) evaluation of RV and LV dimensions and function and interventricular septum curvature using cine MRI; (2) quantification of aortic flow using MR phase velocity mapping; and (3) calculation of the cardiopulmonary peak transit time (PTT) from the pulmonary artery to the ascending aorta using contrast-enhanced, time-resolved, two-dimensional MR angiography. RESULTS: There were no differences between the groups regarding age, height, or weight. In the emphysema patients, ITBV index (- 35%), LV end-diastolic volume index (LVEDVI) [- 21%], RV end-diastolic volume index (- 20%), cardiac index (- 22%), and stroke volume index (SVI) [- 40%] were lower compared to control subjects. LV and RV end-systolic volumes, LV wall mass, septal curvature, and PTT did not differ between the groups. LVEDVI (r = 0.83) as well as SVI (r = 0.82) correlated closely to ITBV index. SVI correlated closely to LVEDVI (r = 0.84). CONCLUSIONS: LV and RV performance is impaired in patients with severe emphysema because of small end-diastolic dimensions. One possible explanation for the decreased biventricular preload in these patients is intrathoracic hypovolemia caused by hyperinflated lungs.
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| 6. |
- Nygren, Andreas, 1967, et al.
(author)
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Autoregulation of human jejunal mucosal perfusion during cardiopulmonary bypass.
- 2006
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In: Anesthesia and analgesia. - 1526-7598. ; 102:6, s. 1617-22
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Journal article (peer-reviewed)abstract
- Animal studies have suggested that autoregulation of intestinal blood flow is severely impaired during cardiopulmonary bypass (CPB). We investigated the jejunal mucosal capacity to autoregulate perfusion during nonpulsatile CPB (34 degrees C) in 10 patients undergoing elective cardiac surgery. Changes in mean arterial blood pressure (MAP) were induced by altering the CPB flow rate randomly for periods of 3 min from 2.4 L/min/m2 to either 1.8 or 3.0 L/min/m2. Jejunal mucosal perfusion (JMP) was continuously recorded by laser Doppler flowmetry. A typical pattern of flow motion (vasomotion) was recorded in all patients during CPB. Variations in CPB flow rates caused no significant changes in mean JMP, jejunal mucosal hematocrit, or red blood cell velocity within a range of MAP from 50 +/- 15 to 74 +/- 16 mm Hg. The vasomotion frequency and amplitude was positively correlated with CPB flow rate. IV injections of prostacyclin (10 microg, Flolan) blunted vasomotion and increased JMP from 192 +/- 53 to 277 +/- 70 (P < 0.05) perfusion units despite a reduction in MAP from 59 +/- 12 to 45 +/- 10 mm Hg (P < 0.05). Prostacyclin-induced vasodilation resulted in loss of mucosal autoregulation (pressure-dependent perfusion). We conclude that autoregulation of intestinal mucosal perfusion is maintained during CPB in humans.
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| 7. |
- Olegård, Cecilia, 1967, et al.
(author)
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Estimation of functional residual capacity at the bedside using standard monitoring equipment: a modified nitrogen washout/washin technique requiring a small change of the inspired oxygen fraction.
- 2005
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In: Anesthesia and analgesia. - 0003-2999. ; 101:1
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Journal article (peer-reviewed)abstract
- We developed a modified nitrogen washin/washout technique based on standard monitors using inspiratory and end-tidal gas concentration values for functional residual capacity (FRC) measurements in patients with acute respiratory failure (ARF). For validation we used an oxygen-consuming lung model ventilated with an inspiratory oxygen fraction (Fio(2)) between 0.3 and 1.0. The respiratory quotient of the lung model was varied between 0.7 and 1.0. Measurements were performed changing Fio(2) with fractions of 0.1, 0.2, and 0.3. In 28 patients with ARF, duplicate measurements were performed. In the lung model, an Fio(2) change of 0.1 resulted in a value of 103 +/- 5% of the reference FRC value of the lung model, and the precision was equally good up to an Fio(2) of 1.0 with a value of 103 +/- 7%. In the patients, duplicate measurements showed a bias of -5 mL with a 95% confidence interval [-38; 29 mL ]. A comparison of a change in Fio(2) of 0.1 with 0.3 showed a bias of -9 mL and limits of agreement of [-365; 347 mL]. This study shows good precision of FRC measurements with standard monitors using a change in Fio(2) of only 0.1. Measurements can be performed with equal precision up to an Fio(2) of 1.0.
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| 8. |
- Thorén, Anders, 1955, et al.
(author)
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Cardiopulmonary bypass in humans--jejunal mucosal perfusion increases in parallel with well-maintained microvascular hematocrit.
- 2005
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In: Acta anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 49:4, s. 502-9
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Journal article (peer-reviewed)abstract
- BACKGROUND: An imbalance between splanchnic oxygen supply and demand occurs during cardiopulmonary bypass (CPB) in man, which might disrupt the intestinal mucosal barrier function. The aim of the present study was to evaluate the effects of mild hypothermic CPB on intestinal mucosal perfusion in man undergoing cardiac surgery. Additionally we aimed to identify variables, which independently could predict changes of intestinal mucosal microcirculatory variables during CPB. METHODS: Jejunal mucosal perfusion (JMP), jejunal mucosal hematocrit (JMHt), red blood cell (RBC) velocity and arteriolar vasomotion using endoluminal jejunal laser Doppler flow metry were studied in eight cardiac surgical patients before and during CPB at a temperature of 34 degrees C. RESULTS: Cardiopulmonary bypass and the accompanied hemodilution (25-30%) induced a 44% increase in JMP (P < 0.05) and a 42% increase in RBC velocity (P < 0.01), with no change in JMHt. The oscillation amplitude of JMP, at a fundamental frequency of 2.8 cycles min(-1), increased with 175% (P < 0.05) during CPB. Splanchnic oxygen extraction increased by 64% during CPB (P < 0.05). Stepwise multiple regression analysis identified systemic hematocrit, arterial O2 and CO2 tension and splanchnic oxygen extraction as independent predictors of RBC velocity during CPB (R2=0.63, P < 0.001). The oscillation amplitude of JMP was predicted by RBC velocity and splanchnic oxygen extraction (R2= 0.68, P <0.0001). CONCLUSIONS: The increase in RBC velocity and enhanced arteriolar vasomotion, as well as maintained jejunal mucosal hematocrit, are microcirculatory, compensatory mechanisms for the splanchic oxygen supply/demand mismatch seen during cardiopulmonary bypass in humans.
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| 9. |
- Hyllner, Monica, 1964, et al.
(author)
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Recombinant activated factor VII in the management of life-threatening bleeding in cardiac surgery
- 2005
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In: Eur J Cardiothorac Surg. - : Oxford University Press (OUP). - 1010-7940. ; 28:2, s. 254-8
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Massive perioperative bleeding is a potential complication of cardiac surgery, and may persist despite conventional interventions. RFVIIa is being increasingly used as additional therapy, and the aim of the present study was to describe our experience with rFVIIa in the management of life-threatening bleeding in adult cardiac surgery. METHODS: Retrospective chart review of 24 patients undergoing a variety of cardiac procedures was performed at Sahlgrenska University Hospital between January and August 2004. The patients developed life-threatening bleeding during or after surgery despite conventional medical therapy and transfusion of blood products, and received rFVIIa as additional therapy. RESULTS: RFVIIa was administered as a median bolus dose of 60 microg/kg. Nineteen patients received one dose of rFVIIa; the bleeding stopped or decreased in 18 of them. Five patients received repeated doses of rFVIIa. Fifteen patients were reexplored due to massive postoperative bleeding or cardiac tamponade and a surgical source of bleeding was identified in six of these patients. A statistically significant reduction in chest drain losses after administration of rFVIIa was demonstrated. No adverse reactions were noted. CONCLUSIONS: RFVIIa was successfully used as an additional therapy both during and after cardiac surgery, when bleeding was refractory to conventional methods. Bleeding stopped eventually in all patients and none of the patients exsanguinated.
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