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Background: Pulmonary hypertension is a significant risk factor in patients undergoing surgery. The combined effects of general anaesthesia and positive pressure ventilation can aggravate this condition and cause increased pulmonary blood pressures, reduced systemic blood pressures and ventricular contractility. Although perioperative use of inotropic support or vasopressors is almost mandatory for these patients, preference is disputed. In this study, we investigated the effects of norepinephrine and dobutamine and their ability to improve the arterio-ventricular relationship and haemodynamics in pigs suffering from chronic pulmonary hypertension., Method: Pulmonary hypertension was induced in five pigs by banding the pulmonary artery at 2-3 weeks of age. Six pigs served as controls. After 16 weeks of pulmonary artery banding, the animals were re-examined under general anaesthesia using biventricular conductance catheters and a pulmonary artery catheter. After baseline measurements, the animals were exposed to both norepinephrine and dobutamine infusions in incremental doses, with a stabilising period in between the infusions. The hypothesis of differences between norepinephrine and dobutamine with incremental doses was tested using repeated two-way ANOVA and Bonferroni multiple comparisons post-test., Results: At baseline, pulmonary artery-banded animals had increased right ventricular pressure (+ 39%, p = 0.04), lower cardiac index (- 23% p = 0.04), lower systolic blood pressure (- 13%, p = 0.02) and reduced left ventricular end-diastolic volume (- 33%, p = 0.02). When incremental doses of norepinephrine and dobutamine were administered, the right ventricular arterio-ventricular coupling was improved only by dobutamine (p < 0.05). Norepinephrine increased both left ventricular end-diastolic volume and left ventricular contractility to a greater extent (p < 0.05) in pulmonary artery-banded animals. While the cardiac index was improved equally by norepinephrine and dobutamine treatments in pulmonary artery-banded animals, norepinephrine had a significantly greater effect on mean arterial pressure (p < 0.05) and diastolic arterial pressure (p < 0.05)., Conclusion: While norepinephrine and dobutamine improved cardiac index equally, it was obtained in different manners. Dobutamine significantly improved the right ventricular function and the arterio-ventricular coupling. Norepinephrine increased systemic resistance, thereby improving arterial pressures and left ventricular systolic function by maintaining left ventricular end-diastolic volume.

Background and Aim: This study aimed to assess right ventricular (RV) function during cardiogenic shock due to acute left ventricular (LV) failure, including during LV unloading with Impella CP and an added moderate dose of norepinephrine., Methods: Cardiogenic shock was induced by injecting microspheres in the left main coronary artery in 18 adult Danish Landrace pigs. Conductance catheters were placed in both ventricles and pressure-volume loops were recorded simultaneously., Results: Cardiogenic shock due to LV failure also impaired RV performance, which was partially restored during haemodynamic support with Impella CP, as demonstrated by changes in the ventriculo-arterial coupling (Ea/Ees ratio) (baseline (median [Q1;Q3]) 1.2 [1.1;1.6]), cardiogenic shock (3.0 [2.4;4.5]), Impella CP (2.1 [1.3;2.7]) (p Baseline vs CS < 0.0001, p CS vs Impella = 0.001)). Impella CP support also improved RV stroke work (SW) (cardiogenic shock 333 [263;530] vs Impella CP (830 [717;1121]) (p < 0.001). Moderate norepinephrine infusion concomitant with Impella CP further improved RV SW (Impella CP (818 [751;1065]) vs Impella CP+moderate norepinephrine (1231 [1142;1335]) (p = 0.01)) but at the expense of an increase in LV SW (Impella CP (858 [555;1392]) vs Impella CP+moderate norepinephrine (2101 [1024;2613]) (p = 0.04))., Conclusions: The Impella CP provided efficient LV unloading, improved RV function, and end-organ perfusion. Moderate doses of norepinephrine during Impella support further improved RV function, but at the expense of an increase in SW of the failing LV.

Background: Pleural effusion (PLE) may lead to low blood pressure and reduced cardiac output. Low blood pressure and reduced cardiac output are often treated with fluid loading and vasopressors. This study aimed to determine the impact of fluid loading and norepinephrine infusion on physiologic determinants of cardiac function obtained by ultrasonography during PLE., Methods: In this randomised, blinded, controlled laboratory study, 30 piglets (21.9 ± 1.3 kg) had bilateral PLE (75 mL/kg) induced. Subsequently, the piglets were randomised to intervention as follows: fluid loading (80 mL/kg/h for 1.5 h, n = 12), norepinephrine infusion (0.01, 0.03, 0.05, 0.1, 0.2 and 0.3 μg/kg/min (15 min each, n = 12)) or control (n = 6). Main outcome was left ventricular preload measured as left ventricular end-diastolic area. Secondary endpoints included contractility and afterload as well as global measures of circulation. All endpoints were assessed with echocardiography and invasive pressure-flow measurements., Results: PLE decreased left ventricular end-diastolic area, mean arterial pressure and cardiac output (p values < 0.001), but fluid loading (20 mL/kg) and norepinephrine infusion (0.05 μg/kg/min) restored these values (p values > 0.05) to baseline. Left ventricular contractility increased with norepinephrine infusion (p = 0.002), but was not affected by fluid loading (p = 0.903). Afterload increased in both active groups (p values > 0.001). Overall, inferior vena cava distensibility remained unchanged during intervention (p values ≥ 0.085). Evacuation of PLE caused numerical increases in left ventricular end-diastolic area, but only significantly so in controls (p = 0.006)., Conclusions: PLE significantly reduced left ventricular preload. Both fluid and norepinephrine treatment reverted this effect and normalised global haemodynamic parameters. Inferior vena cava distensibility remained unchanged. The haemodynamic significance of PLE may be underestimated during fluid or norepinephrine administration, potentially masking the presence of PLE.