Perioperative right ventricular dysfunction. Curr Opin Anaesthesiol. 2013;26:71-81. [PMID: 23235519 DOI: 10.1097/aco.0b013e32835b8be2]

Intratracheal Milrinone Bolus Administration During Acute Right Ventricular Dysfunction After Cardiopulmonary Bypass

OBJECTIVE

To evaluate intratracheal milrinone (tMil) administration for rapid treatment of right ventricular (RV) dysfunction as a novel route after cardiopulmonary bypass.

DESIGN

Retrospective analysis.

SETTING

Single-center study.

PARTICIPANTS

The study comprised 7 patients undergoing cardiac surgery who exhibited acute RV dysfunction after cardiopulmonary bypass.

INTERVENTIONS

After difficult weaning caused by cardiopulmonary bypass-induced acute RV dysfunction, milrinone was administered as a 5-mg bolus inside the endotracheal tube.

MEASUREMENTS AND MAIN RESULTS

RV function improvement, as indicated by decreasing pulmonary artery pressure and changes of RV waveforms, was observed in all 7 patients. Adverse effects of tMil included dynamic RV outflow tract obstruction (2 patients) and a decrease in systemic mean arterial pressure (1 patient).

CONCLUSIONS

tMil may be an effective, rapid, and easily applicable therapeutic alternative to inhaled milrinone for the treatment of acute RV failure during cardiac surgery. However, sufficiently powered clinical trials are needed to confirm these findings.

A novel semiquantitative assessment of right ventricular systolic function with a modified subcostal echocardiographic view

OBJECTIVES

The tricuspid annular plane systolic excursion (TAPSE) is a validated measure of right ventricular function; however, the apical echocardiographic window varies and has limitations in intensive care unit (ICU) patients receiving mechanical ventilation or those with underlying disease and air entrapment. We aimed to evaluate the subcostal echocardiographic assessment of tricuspid annular kick (SEATAK) as an alternative to TAPSE in critically ill patients.

METHODS

To measure SEATAK, we obtained the subcostal inferior vena cava view and used M-mode to measure excursion of the tricuspid annulus (kick). Analysis was performed with JMP for Bland-Altman and Spearman correlations.

RESULTS

We evaluated 45 patients, 26 (57.8%) of whom were women, with a mean age of 60.8 years. We were not able to obtain the apical view to measure TAPSE in 8.9% of the patients. In contrast, SEATAK was measured in all patients. The mean SEATAK and TAPSE were 1.62 cm and 1.93 cm, respectively, with a mean pairwise difference of -0.26 cm (95% CI: -0.19 to -0.35), with the SEATAK value being lower than TAPSE. The overall correlation was strong and significant (ρ = .86, P=.03). The graphical correlation was maintained between TAPSE and SEATAK and the degree of RVF.

CONCLUSION

In patients presenting with RVF in the ICU (or in situations where the apical echocardiographic view is suboptimal for tricuspid annular assessment), SEATAK can be an alternative to TAPSE. Further research is needed to validate and determine the sensitivity and specificity of SEATAK for RVF prognostication.

Right Ventricular Longitudinal Strain Is Depressed in a Bovine Model of Pulmonary Hypertension

BACKGROUND

Pulmonary hypertension and resulting right ventricular (RV) dysfunction are associated with significant perioperative morbidity and mortality. Although echocardiography permits real-time, noninvasive assessment of RV function, objective and comparative measures are underdeveloped, and appropriate animal models to study their utility are lacking. Longitudinal strain analysis is a novel echocardiographic method to quantify RV performance. Herein, we hypothesized that peak RV longitudinal strain would worsen in a bovine model of pulmonary hypertension compared with control animals.

METHODS

Newborn Holstein calves were randomly chosen for induction of pulmonary hypertension versus control conditions. Pulmonary hypertension was induced by exposing animals to 14 days of hypoxia (equivalent to 4570 m above sea level or 430 mm Hg barometric pressure). Control animals were kept at ambient pressure/normoxia. At the end of the intervention, transthoracic echocardiography was performed in awake calves. Longitudinal wall strain was analyzed from modified apical 4-chamber views focused on the RV. Comparisons between measurements in hypoxic versus nonhypoxic conditions were performed using Student t test for independent samples and unequal variances.

RESULTS

After 14 days at normoxic versus hypoxic conditions, 15 calves were examined with echocardiography. Pulmonary hypertension was confirmed by right heart catheterization and associated with reduced RV systolic function. Mean systolic strain measurements were compared in normoxia-exposed animals (n = 8) and hypoxia-exposed animals (n = 7). Peak global systolic longitudinal RV strain after hypoxia worsened compared to normoxia (-10.5% vs -16.1%, P = 0.0031). Peak RV free wall strain also worsened after hypoxia compared to normoxia (-9.6% vs -17.3%, P = 0.0031). Findings from strain analysis were confirmed by measurement of tricuspid annular peak systolic excursion.

CONCLUSIONS

Peak longitudinal RV strain detected worsened RV function in animals with hypoxia-induced pulmonary hypertension compared with control animals. This relationship was demonstrated in the transthoracic echocardiographic 4-chamber view independently for the RV free wall and for the combination of the free and septal walls. This innovative model of bovine pulmonary hypertension may prove useful to compare different monitoring technologies for the assessment of early events of RV dysfunction. Further studies linking novel RV imaging applications with mechanistic and therapeutic approaches are needed.

Right Ventricular Depression After Cardiopulmonary Bypass for Valvular Surgery

OBJECTIVE

To assess if right ventricular (RV) dysfunction is associated with increased mortality after cardiac surgery.

DESIGN

Post-hoc analysis of a single-center double-blind randomized controlled trial.

SETTING

University hospital.

PARTICIPANTS

A total of 120 patients undergoing simple or complex valvular surgery.

INTERVENTIONS

Patients were randomized to receive intravenous amiodarone or placebo intraoperatively. As secondary analysis, patients were divided into those requiring or not requiring postoperative inotropic agents.

MEASUREMENTS AND MAIN RESULTS

After cardiopulmonary bypass (CPB), there were significant increases in heart rate, cardiac index, systolic and mean arterial pressures, central venous pressure and pulmonary capillary wedge pressure with reduction in systemic vascular resistance (p<0.05). Right ventricular end-systolic area became larger in those without inotropes and tricuspid annular plane systolic excursion was reduced in all patients; mitral annular systolic velocities were higher in patients receiving inotropes. Both right- and left-sided Doppler signals were altered significantly after CPB, which may be attributed to increased filling pressure. Inotropic agents were required in 56 patients after CPB (47%). The use of inotropic agents was associated with increased left and right atrial velocities (p<0.05). There were no differences in postoperative complications between groups; however, the number of deaths at 6 years was increased in patients who received inotropes after CPB (p = 0.0247).

CONCLUSIONS

The increases in right-sided dimensions after CPB are associated with reduction in RV function and increased biventricular filling pressure, suggesting worsening biventricular function and interventricular dependence. Inotropic medications were associated with unaltered RV dimensions and increased biatrial activity.

Innovative approaches in the perioperative care of the cardiac surgical patient in the operating room and intensive care unit

Perioperative care for cardiac surgery is undergoing rapid evolution. Many of the changes involve the application of novel technologies to tackle common challenges in optimizing perioperative management. Herein, we illustrate recent advances in perioperative management by focusing on a number of novel components that we judge to be particularly important. These include: the introduction of brain and somatic oximetry; transesophageal echocardiographic hemodynamic monitoring and bedside focused ultrasound; ultrasound-guided vascular access; point-of-care coagulation surveillance; right ventricular pressure monitoring; novel inhaled treatment for right ventricular failure; new approaches for postoperative pain management; novel approaches in specialized care procedures to ensure quality control; and specific approaches to optimize the management for postoperative cardiac arrest. Herein, we discuss the reasons that each of these components are particularly important in improving perioperative care, describe how they can be addressed, and their impact in the care of patients who undergo cardiac surgery.

Bedside clinical and ultrasound-based approaches to the management of hemodynamic instability--part I: focus on the clinical approach: continuing professional development

Shock is defined as a situation where oxygen transport is inadequate to meet the body's oxygen demand. An understanding of the mechanism(s) of reduced cardiac output, a determinant of oxygen transport, is crucial in order to initiate appropriate therapy to manage shock. Combining the concept of venous return with the ventricular pressure-volume relationship is a useful method to appreciate the complex circulatory physiology of shock. Clues from the patient's history, physical examination, and key laboratory tests, along with the careful inspection of hemodynamic, electrocardiographic and respiratory waveforms can help with the identification of the etiology and mechanism(s) of shock. Following verification of the arterial pressure, general resuscitation can begin, and more specific treatment can be undertaken to manage shock. If the patient is unresponsive to these measures, bedside ultrasound can then be performed to ascertain more detail regarding the mechanism(s) and etiology of shock.

PURPOSE

To develop an approach to the management of the hemodynamically unstable patient.

PRINCIPAL FINDING

Not applicable.

CONCLUSION

Not applicable.

Practical diastology

Left ventricular (LV) diastolic dysfunction is being recognized as an important part in the pre-operative evaluation. Pre-operative LV diastolic dysfunction has been associated with increased risk of post-operative complications. Furthermore guidelines have been published on the assessment of LV diastolic function. However LV diastolic function is significantly influenced by loading conditions which are typically altered during cardiac and non-cardiac surgery. In addition, waveform analysis from the pulmonary artery catheter tend to correlate with diastolic function and loading conditions. The advantage of hemodynamic monitoring being that they are continuously displayed as opposed to intermittent diastolic parameters. Finally if the importance of diastolic function assessment is to estimate filling pressure, the presence of B lines with the use of lung ultrasound is a simpler method in detecting pulmonary edema. Another indirect evidence of either LV systolic or diastolic dysfunction is an abnormal near-infrared spectroscopy value. Finally it might be more important to evaluate right ventricular (RV) diastolic dysfunction as RV dysfunction is significantly associated with pulmonary hypertension and consequently mortality. Such assessment of RV diastolic dysfunction can be obtained continuously with the use of RV pressure waveform monitoring.