Monitoring of infusion therapy in patients with reduced cardiac reserve during abdominal operations

Abstract

Background. In the pathogenesis of many intra- and postoperative complications, the composition, volume and rate of infusion therapy (IT) play a significant role. This problem is especially relevant for patients with concomitant chronic pathology of the cardiovascular, respiratory systems and kidneys. Informative indicators for assessing the correctness of IT and early diagnosis of intraoperative complications associated with errors in its implementation are complex monitoring of functional indicators of the cardiovascular and respiratory systems. Purpose – of the study is to investigate changes in biochemical markers of heart failure and ultrasound signs of venous stasis in two modes of infusion therapy (restrictive and liberal), on the basis of a comparative study, to determine the optimal mode of perioperative IT in patients undergoing elective surgery for diseases of the abdominal cavity and have comorbid pathology in the form of coronary heart disease (CHD) and heart failure (HF). Materials and Methods. 86 patients were included in a single-center, prospective, randomized study. All patients were randomly divided into two groups depending on the mode of intraoperative IT: in the first group (n = 44) – a restrictive mode of 5–8 ml/kg/hour was applied, in the second (n = 42) – a liberal mode. Echocardiography was performed at the stages of the study. Heart contractility, central hemodynamics, and ejection fraction were evaluated. An ultrasound scan of the inferior vena cava (IVC) was performed during breathing as a non-invasive method of assessing the intravascular blood volume. The diameter of the vein during inhalation and exhalation was evaluated. Based on the respiratory change in the diameter of the IVC, the caval index is calculated, which is expressed as a percentage. An index approaching 100% indicates near-complete collapse and probable volume depletion, while an index close to 0% indicates minimal collapse and intravascular overflow. Ultrasound of the lungs was performed according to the BLUE protocol with a convex sensor in 8 zones along the front chest wall. The severity of pulmonary congestion was assessed based on the sum of B-lines: 5 and less – no congestion, 6 to 15 – slight congestion, 15 to 29 – moderate, 30 and more – significant. Results. The conducted study shows the advantage of the restrictive regimen of IT in patients with concomitant coronary artery disease and minimal signs of congestive heart failure during abdominal surgical operations. The regime with restriction of intravenous fluid administration was better, as it reduces venous congestion, reduces the amount of fluid in the interstitial space of the lungs, causes a smaller compensatory reaction of the cardiovascular system to infusion with normal values of NT-proBNP. The task of the anesthesiologist in this case is careful control of daily and cumulative water balance, adequate monitoring of indicators of the cardiovascular system, use of modern ultrasound technologies and protocols for controlling volemic status, assessment of the dynamics of biomarkers of heart failure, which will allow complex abdominal operations to be safely performed in patients with reduced cardiac reserve. Conclusions. As a result of the conducted research, it was established that: the use of a liberal regimen of infusion therapy in the perioperative period in patients with coronary heart disease and HF I, I-II FC compared to a restrictive regimen leads to a statistically significant increase in biomarkers of heart failure and ultrasound signs of volemic overload. The restrictive regimen of IT in a dose of 5–8 ml/kg/hour, in comparison with a liberal one in a dose of 12–15 ml/kg/hour, can be recognized as optimal and safe in patients with coronary heart disease and HF I, I-II FC during surgery on the organs of the abdominal cavity. The use and widespread implementation in practice of complex determination of the level of the amino-terminal prohormone of brain natriuretic peptide (NT-proBNP) NT-proBNP, non-invasive methods of ultrasound of the heart – echocardiography, ultrasound of the lungs and central vessels – assessment of the dynamic filling of the inferior vena cava (IVC) allows significantly supplement clinical information on volemic status, venous stasis, contractility of the heart and fluid retention in the interstitial space of the lungs and may be key in the prevention of cardiac complications in this category of patients.