Intraoperative Hemodynamic Instability During and After Separation From Cardiopulmonary Bypass

Abstract

Every year, more than 1 million patients worldwide undergo cardiac surgery. Because of the aging of the population, cardiac surgery will increasingly be offered to patients at a higher risk of complications. The consequence is a reduced physiological reserve and hence an increased risk of mortality. These issues will have a significant impact on future health care costs because the population undergoing cardiac surgery will be older and more likely to develop postoperative complications. One of the most dreaded complications in cardiac surgery is difficult separation from cardiopulmonary bypass (CPB). When separation from CPB is associated with right-ventricular failure, the mortality rate will range from 44% to 86%. Therefore, the diagnosis and the preoperative prediction of difficult separation from CPB will be crucial to improve the selection and care of patients and to prevent complications for this high-risk patient population.

Reduced Right Ventricular Function Predicts Long-Term Cardiac Re-Hospitalization after Cardiac Surgery

“…The RV is affected by changes in afterload, preload, and contractility [ 12 , 13 ]. In surgical patients, some consideration of RV function is warranted as many surgically relevant disease states may potentially alter such determinants of RV function [ 14 , 15 ].…”

Hepatic and renal effects of cardiopulmonary bypass

“…Congestive hepatopathy, also known as "nutmeg liver" [17], is a liver dysfunction usually associated to right heart failure [18]. Venous congestion couples with high CVP, fluid retention and blood stasis, and it is related to the deoxygenation of hepatocytes surrounding the central venule of the liver.…”

Bedside clinical and ultrasound-based approaches to the management of hemodynamic instability - Part I: focus on the clinical approach: Continuing Professional Development

“…In order to help identify the mechanism of shock, we combine three complementary elements: A) the concept of venous return (VR); B) the ventricular pressure-volume relationship; and C) the use of bedside ultrasound. 13 Hemodynamic assessment of shock often begins with the determination of CO, heart rate and rhythm, preload, afterload, and contractility. The CO represents the blood pumped from the heart, which in a closed cardiovascular system must equal the VR to the heart.…”

“…Dans le cas d'une obstruction de la chambre de chasse du LV ou du RV, le volume du LV ou du RV est réduit mais la pression intraventriculaire est augmentée (5I) et la courbe de VR est déplacée vers la droite (5L). (D'après 13 ) peak P waves in acute pulmonary embolism, elevated T waves in brain-heart syndrome, Osborn waves in hypothermia, and microvoltage in tamponade (Fig. 7).…”

“…Pour aider à identifier le mécanisme du choc, nous combinons trois éléments complémentaires: A) le concept de retour veineux; B) la relation pression-volume ventriculaire; et C) l'utilisation de l'échographie au chevet du patient. 13 L'évaluation hémodynamique du choc commence souvent par la détermination des paramètres suivants: débit cardiaque, fréquence et rythme cardiaque, précharge, postcharge et contractilité. Le débit cardiaque représente le sang pompé par le coeur, ce qui, dans un système cardiovasculaire fermé, doit être égal au retour veineux vers le coeur.…”