Right ventricular end-systolic pressure-volume relation during propofol infusion

Arrhythmias in Patients with Pulmonary Hypertension and Right Ventricular Failure: Importance of Rhythm Control Strategies

Arrhythmias frequently complicate the course of advanced pulmonary hypertension, often leading to hemodynamic compromise, functional impairment, and mortality. Given the importance of right atrial function in this physiology, the restoration and maintenance of sinus rhythm are of critical importance. In this review, we outline the pathophysiology of arrhythmias and their impact on right heart performance; describe considerations for antiarrhythmic drug selection, anesthetic and periprocedural management; and discuss the results of catheter ablation techniques in this complex and challenging patient population.

Effect of Anesthesia Induction on Cardiac Hemodynamics in Patients Undergoing Durable Left Ventricular Assist Device Implantation: The EACH-LVAD Study

Right ventricular (RV) dysfunction is common after left ventricular assist device (LVAD) implantation leading to clinical right heart failure (RHF) associated with worsened survival and quality of life. It is likely that intraoperative events such as anesthesia induction play a role in the development or unmasking of RV dysfunction in addition to known effects from hemodynamic changes that occur after LVAD implantation. The EACH-LVAD Study is a prospective, single-center, single-arm, observational cohort study of adult patients with advanced heart failure undergoing durable LVAD implantation with standard anesthesia induction. Intraoperative RV hemodynamics via central venous pressure, mean pulmonary artery pressure, pulmonary artery pulsatility index, and vasoactive-inotropic score (a simple weighted summation of standardized drug doses) and echocardiographic parameters (RV fractional area change, RV area in diastole, RV basal diameter, septum position, RV function, tricuspid regurgitation) were measured and compared at prespecified timepoints, including postinduction. Postoperative clinical RHF was determined based on published definitions. Forty-two patients receiving a first-time LVAD were included between September 2017 and March 2019. Propofol-based induction was used in 31 patients and etomidate-based induction in eight patients. A significant increase in central venous pressure (CVP; p < 0.001), mean pulmonary artery pressure (mPAP; p < 0.001), and vasoactive inotropic score (VIS; p < 0.001) with associated decrease in pulmonary artery pulsatility index (PAPi; p < 0.001) was observed. Right ventricular function worsened throughout. Right heart failure occurred in 70% of patients. Propofol-based induction was not associated with a higher risk of RHF (relative risk [RR], 1.01 [95% confidence interval {CI}, 0.64-1.61]). The EACH-LVAD study demonstrates an effect of anesthesia induction on worsened RV hemodynamics and echocardiographic changes which may have an effect on the development of RHF.

The effects of anesthesia induction and positive pressure ventilation on right-ventricular function: an echocardiography-based prospective observational study

Background

General anesthesia induction with the initiation of positive pressure ventilation creates a vulnerable phase for patients. The impact of positive intrathoracic pressure on cardiac performance has been studied but remains controversial. 3D echocardiography is a valid and MRI-validated bed-side tool to evaluate the right ventricle (RV). The aim of this study was to assess the impact of anesthesia induction (using midazolam, sufentanil and rocuronium, followed by sevoflurane) with positive pressure ventilation (PEEP 5, tidal volume 6–8 ml/kg) on 2D and 3D echocardiography derived parameters of RV function.

Methods

A prospective observational study on fifty-three patients undergoing elective cardiac surgery in a tertiary care university hospital was designed. Transthoracic echocardiography exams were performed before and immediately after anesthesia induction and were recorded together with hemodynamic parameters and ventilator settings.

Results

After anesthesia induction TAPSE (mean difference − 1.6 mm (95% CI − 2.6 mm to − 0.7 mm; p = 0.0013) as well as the Tissue Doppler derived tricuspid annulus peak velocity (TDITVs’) were significantly reduced (mean difference − 1.9% (95% CI: − 2.6 to − 1.2; p < 0.0001), but global right ventricular ejection fraction (RVEF; p = 0.1607) and right ventricular stroke volume (RVSV; p = 0.1838) did not change.

Conclusions

This data shows a preserved right ventricular ejection fraction and right ventricular stroke volume after anesthesia induction and initiation of positive pressure ventilation. However, the baso-apical right ventricular function is significantly reduced. Larger studies are needed in order to determine the clinical impact of these findings especially in patients presenting with impaired right ventricular function before anesthesia induction.

Trial registration

Retrospecitvely registered, 6th June 2016, ClinicalTrials.gov Identifier NCT02820727.

General anesthesia and positive pressure ventilation suppress left and right ventricular myocardial shortening in patients without myocardial disease - a strain echocardiography study

BACKGROUND

Myocardial deformation imaging using speckle-tracking echocardiography to assess global longitudinal strain (GLS) is today considered a more sensitive measure of left ventricular (LV) systolic function than ejection fraction. General anesthesia and positive pressure ventilation (PPV) are known to change the right ventricular (RV) and LV loading conditions. However, little is known about the effects of anesthesia and PPV on RV free wall and LV GLS. We studied the influence of general anesthesia and PPV on RV and LV longitudinal strain in patients without myocardial disease.

METHODS

Twenty-one patients scheduled for non-cardiac surgery were included. The baseline examination was performed on the un-premedicated patients within 60 min of anesthesia. The second examination was performed 10-15 min after induction of anesthesia (propofol, remifentanil), intubation and start of PPV. The examinations included apical four-, two- and three-chamber projections, mitral and aortic Doppler flow velocities and tissue Doppler velocities of tricuspid and mitral annulus. LV end-systolic elastance (Ees) and aortic elastance were determined (Ea).

RESULTS

General anesthesia and PPV reduced the mean arterial blood pressure (- 29%, p <  0.0019), stroke volume index (- 13%, p <  0.001) and cardiac index (- 23%, p <  0.001). RV end-diastolic area index and LV end-diastolic volume index decreased significantly, while systemic vascular resistance was not significantly affected. Ees decreased significantly with the induction of anaesthesia (- 23%, p = 0.002), while there was a trend for a decrease in Ea (p = 0.053). The ventriculo-arterial coupling, Ea/Ees, was not significantly affected by the anesthetics and PPV. The LV GLS decreased from - 19.1 ± 2.3% to - 17.3 ± 2.9% (p <  0.001) and RV free wall strain decreased from - 26.5 ± 3.9% to - 24.1 ± 4.2% (p = 0.001). One patient (5%) had at baseline a LV GLS > - 16% compared with 6 patients (28%) during general anesthesia and PPV. Three patients (14%) had a RV free wall strain > - 24% compared to 8 patients (38%) during general anesthesia and PPV.

CONCLUSIONS

General anesthesia and PPV reduces systolic LV and RV function to levels considered indicating dysfunction in a substantial proportion of patients without myocardial disease.

Prevalence and risk factors for intraoperative hypotension during craniotomy for traumatic brain injury

BACKGROUND

Hypotension after traumatic brain injury (TBI) is associated with poor outcomes. However, data on intraoperative hypotension (IH) are scarce and the effect of anesthetic agents on IH is unknown. We examined the prevalence and risk factors for IH, including the effect of anesthetic agents during emergent craniotomy for isolated TBI.

METHODS

This is a retrospective cohort study of patients 18 years and above, who underwent emergent craniotomy for TBI at Harborview Medical Center (level 1 trauma center) between October 2007 and January 2010. Demographic, clinical, and radiographic characteristics and hemodynamic and anesthetic data were abstracted from medical and electronic anesthesia records. Hypotension was defined as systolic blood pressure <90 mm Hg. Univariate analyses were performed to compare the clinical characteristics of patients with and without IH, and multiple logistic regression analysis was used to determine independent risk factors for IH.

RESULTS

Data abstracted from 113 eligible patients aged 48±19 years were analyzed. IH was common (n=73, 65%) but not affected by the choice of anesthetic agent. Independent risk factors for IH were multiple computed tomographic (CT) lesions [adjusted odds ratios (AOR) 19.1; 95% confidence interval (CI), 2.08-175.99; P=0.009], subdural hematoma (AOR 17.9; 95% CI, 2.97-108.10; P=0.002), maximum CT lesion thickness (AOR 1.1; 95% CI, 1.01-1.13; P=0.016), and anesthesia duration (AOR 1.1; 95% CI, 1.01-1.30; P=0.009).

CONCLUSIONS

IH was common in adult patients with isolated TBI undergoing emergent craniotomy. The presence of multiple CT lesions, subdural hematoma, maximum thickness of CT lesion, and longer duration of anesthesia increase the risk for IH.

Anaesthesia and right ventricular failure

Acute right ventricular (RV) failure has until recently received relatively little attention in the cardiology, critical care or anaesthesia literature. However, it is frequently encountered in cardiac surgical cases and is a significant cause of mortality in patients with severe pulmonary hypertension who undergo non-cardiac surgery. RV dysfunction may be primarily due to impaired RV contractility, or volume or pressure overload. In these patients, an increased pulmonary vascular resistance (PVR) or a decreased aortic root pressure may lead to RV ischaemia, resulting in a rapid, downward haemodynamic spiral. The key aspects of 'RV protection' in patients who are at risk of perioperative decompensation are prevention, detection and treatment aimed at reversing the underlying pathophysiology. Minimising PVR and maintaining systemic blood pressure are of central importance in the prevention of RV decompensation, which is characterised by a rising central venous pressure and a falling cardiac output. Although there are no outcome data to support any therapeutic strategy for RV failure when PVR is elevated, the combination of inhaled iloprost or intravenous milrinone with oral sildenafil produces a synergistic reduction in PVR, while sparing systemic vascular resistance. Levosimendan is a promising new inotrope for the treatment of RV failure, although its role in comparison to older agents such as dobutamine, adrenaline and milrinone has yet to be determined. This is also the case for the use of vasopressin as an alternative pressor to noradrenaline. If all else has failed, mechanical support of the RV should be considered in selected cases.

Xenon alters right ventricular function

BACKGROUND

In contrast to other volatile anesthetics, xenon produces less cardiovascular depression with fewer fluctuations of various hemodynamic parameters, but reduces cardiac output (CO) in vivo. Besides an increase in left ventricular afterload and reduction of heart rate, an impairment of the right ventricular function might be an additional pathophysiological mechanism for the reduction of CO. Therefore, we used an animal model to study the effects of xenon as a supplemental anesthetic on right ventricular function, especially right ventricular afterload.

METHODS

Right ventricular function was monitored with a volumetric pulmonary artery catheter in 11 pigs during general anesthesia with thiopental. Six animals received additional 70% (volume) xenon (equivalent to 0.55 MAC minimum alveolar concentration). Parameters for systolic function, afterload, and preload were calculated at baseline and during 50 min of xenon application, and in a corresponding control group. Significant differences were detected by multivariate analyses of variance for repeated measures.

RESULTS

Xenon reduced CO on average by 30% and increased pulmonary arterial elastance by 60%, which led to a reduction of the right ventricular ejection fraction by 25%. Whereas right ventricular preload remained stable, maximal slope of pulmonary artery pressure and the right ventricular elastance increased. No effect on the ratio of stroke work and end-diastolic volume was found.

CONCLUSION

The reduction in CO during xenon anesthesia was partly due to an impairment of the right ventricular function, mainly caused by an increased afterload, without an impairment of systolic ventricular function.

Left ventricular systolic and diastolic function is unaltered during propofol infusion in newborn swine

Propofol is a cardiac depressant with minimal diastolic effects in the adult myocardium. Cardiac effects of propofol in the newborn are unknown. We examined hemodynamic variables and systolic and diastolic left ventricular function in 12 newborn pigs exposed to propofol at three different infusion rates (7.5, 15, and 30 mg x kg(-1) x h(-1)) in random order with a background of fentanyl (100 microg x kg(-1) x h(-1)). Left ventricular (LV) pressure (Plv) and LV anterior-posterior dimension, determined by sonomicrometry, were continuously monitored. Mean arterial pressure (MAP), heart rate (HR), and LV end-diastolic pressure (LVEDP) were determined at every infusion. Systolic function was assessed by the maximal pressure-time derivative (dP/dt(max)), the slope of the end-systolic pressure-dimension relationship (ESP-D), and by the preload recruitable stroke work index (PRSWI). Diastolic function was assessed by relaxation indices, the minimal pressure-time derivative (dP/dt(min)) and the relaxation time constant (tau), and by a stiffness index, the slope of the EDP-D relationship. MAP decreased approximately 25%, from 75.9 +/- 15.6 to 56.3 +/- 14.8 mm Hg (P < 0.05) with propofol, with no dose effect. HR and LVEDP were unchanged from control. Both dP/dt(max) and dP/dt(min) decreased with propofol infusion, but load-independent indices of systolic function (ESP-D slope and PRSWI) and tau were unchanged. Diastolic stiffness was not affected with either 7.5- or 30-mg x kg(-1) x h(-1) infusions but decreased significantly from 0.27 +/- 0.18 mm Hg/mm at control to 0.18 +/- 0.18 mm Hg/mm (P < 0.05) with propofol 15 mg x kg(-1) x h(-1). With this profile, propofol may be useful for the newborn requiring anesthesia.

IMPLICATIONS

Most anesthetics depress heart function in the newborn. We examined both heart contraction and relaxation during anesthesia with propofol in newborn pigs. Propofol had minimal influence on heart function in this model at the doses studied. This may therefore be a useful anesthetic to test in the newborn human.