A STUDY ON THE RISK FACTORS CONTRIBUTING TO PROLONGED INTENSIVE CARE UNIT STAYS IN PATIENTS FOLLOWING CARDIAC SURGERY INVOLVING CARDIOPULMONARY BYPASS

CHAPTER ONE INTRODUCTION 1.1 Background of the Study Over the past few decades, cardiac surgery—particularly procedures involving cardiopulmonary bypass (CPB)—has seen significant advancements, leading to better survival rates and overall outcomes for patients suffering from various cardiovascular diseases (Loponen et al., 2020). Despite these improvements, such surgeries still require intensive postoperative care, with many patients experiencing extended stays in the intensive care unit (ICU) due to complications arising either from the surgery itself or pre-existing health conditions. The length of time a patient spends in the ICU following cardiac surgery is a critical indicator of their recovery progress and also serves as a major determinant of healthcare costs and resource allocation (Brown et al., 2018). Among the most commonly performed cardiac procedures using CPB are heart transplants, coronary artery bypass grafting (CABG), and valve surgeries (Ailawadi & Zacour, 2019). While innovations have made CPB procedures safer and more adaptable, various complications still occur. These may include respiratory dysfunction, atrial fibrillation, cognitive impairments, acute kidney injury, systemic inflammation, and coagulation abnormalities (Almashrafi, Elmontsri & Aylin, 2016). As a result, close monitoring in the ICU is essential after surgery to detect changes in patient condition early and manage any arising issues promptly. For some patients, ICU stays after CPB are longer than expected. Although the standard timeframe for defining a prolonged ICU stay typically ranges from three to seven days (Almashrafi et al., 2016), a more specific benchmark of over 72 hours is often used to identify high-risk cases more accurately. These extended stays are linked to higher rates of complications, increased mortality, and a substantial rise in healthcare costs (Chin-Yee et al., 2017). Therefore, identifying the risk factors associated with prolonged ICU admission after cardiac surgery with CPB is vital. Several variables have been shown to contribute to longer ICU stays, including patient age, oxygenation index (PaO2/FiO2 ratios), presence of atrial fibrillation, the type and duration of the surgery, pulmonary hypertension, extended mechanical ventilation, intubation time, the volume of blood transfusions, and the duration of inotropic support in the ICU. These extended stays can negatively impact patient recovery and the healthcare system, underscoring the importance of understanding and managing associated risk factors. Previous studies (Almashrafi, Elmontsri & Aylin, 2016) have mainly focused on preoperative and intraoperative risk factors that influence prolonged ICU stays. However, less attention has been paid to early postoperative variables. In parts of Europe and the United States, scoring systems like EuroSCORE and Parsonnet are commonly used to predict ICU length of stay in cardiac surgery patients (Meadows, Gibbens, Gerrard & Vuylstek, 2018). Yet, these models often fall short when applied in different countries due to varying levels of medical resources and institutional discharge protocols. For this reason, this study seeks to evaluate the specific risk factors that contribute to prolonged ICU stays among patients undergoing cardiac surgery with CPB. 1.2 Statement of the Problem Cardiac surgeries involving cardiopulmonary bypass (CPB) are complex procedures frequently associated with significant postoperative challenges, often resulting in prolonged ICU stays. These extended admissions are not only financially burdensome but also increase the risk of developing secondary complications such as infections, respiratory difficulties, and prolonged mechanical ventilation (Doenst et al., 2019). Identifying the key risk factors contributing to these extended ICU admissions is essential for improving patient outcomes and ensuring more efficient use of healthcare resources. Prior research has recognized various contributing factors, including advanced patient age, underlying health conditions like diabetes and chronic obstructive pulmonary disease, as well as perioperative factors such as the length of CPB use, volume of blood transfusions, and occurrence of surgical complications (Ahlsson et al., 2017; Benedetto et al., 2016). Nevertheless, there remains a lack of consensus on the relative importance of these variables, especially across different healthcare settings and patient populations. Additionally, the variability in patient response to surgical intervention and intensive care makes it difficult to predict the length of ICU stay with accuracy. Therefore, this study is focused on examining the risk factors associated with prolonged ICU stays in patients who have undergone cardiac surgery using CPB. 1.3 Objective of the Study The general aim of this research is to investigate the risk factors associated with extended ICU stays in patients who have undergone cardiac surgery using cardiopulmonary bypass (CPB). The specific objectives are: i. To identify patient-specific factors that contribute to prolonged ICU stays following cardiac surgery with CPB. ii. To examine how postoperative complications influence the length of ICU stays in such patients. iii. To propose clinical practice recommendations aimed at minimizing ICU stay duration and enhancing postoperative recovery for patients undergoing cardiac surgery with CPB. 1.4 Research Questions This study will be guided by the following research questions: i. What patient-specific factors are linked to prolonged ICU stays after cardiac surgery with CPB? ii. How do postoperative complications affect the duration of ICU stays following cardiac surgery with CPB? iii. What clinical recommendations can help reduce ICU stay duration and improve recovery outcomes for patients who have undergone cardiac surgery with CPB? 1.5 Significance of the Study The outcomes of this study hold potential significance for healthcare policymakers, particularly in shaping ICU management strategies and postoperative cardiac care. The findings may help in formulating standardized care protocols, reducing ICU overcrowding, and improving the efficiency of intensive care services. This can ultimately lead to the development of evidence-based guidelines for managing patients after cardiac surgery with CPB. Additionally, the study will be valuable to the academic community. It will enrich the existing body of literature, enhance academic libraries, and serve as a reference for future researchers interested in cardiac surgery, intensive care management, and postoperative outcomes. 1.6 Scope of the Study This study is specifically focused on the risk factors associated with prolonged ICU stays following cardiac surgery using cardiopulmonary bypass. Empirically, it seeks to identify patient-related factors, analyze the influence of postoperative complications on ICU stay duration, and recommend clinical strategies for improving outcomes and reducing ICU occupancy times. Geographically, the study is limited to the Lagos State University Teaching Hospital (LASUTH). 1.7 Limitations of the Study As with many academic endeavors, this study encountered some limitations. One of the primary constraints was time. The researcher had to juggle the demands of this research with other academic responsibilities, including attending lectures and completing assignments. Another limitation was financial constraint, as the research involved costs for printing, data collection, sourcing literature, and general logistics. Lastly, the availability of materials presented a challenge. Due to the specificity of the topic, it was difficult to access sufficient existing literature and relevant scholarly resources. 1.8 Definition of Terms Cardiac Surgery: A medical procedure performed on the heart or nearby blood vessels to address various cardiovascular problems, including blocked arteries, faulty valves, or congenital heart issues. Cardiopulmonary Bypass (CPB): A surgical technique in which a machine temporarily performs the functions of the heart and lungs during certain types of cardiac surgery, allowing the surgeon to work on a motionless and bloodless heart. Intensive Care Unit (ICU): A highly specialized hospital unit where critically ill patients are closely monitored and provided with advanced life-support care, particularly after major surgeries. Length of Stay (LOS): The number of days a patient remains in the ICU from admission to discharge. Prolonged ICU Stay: A lengthier-than-normal stay in the ICU, often defined as exceeding 48 to 72 hours, though the threshold can vary depending on the clinical context. Preoperative Risk Factors: Patient characteristics or medical conditions present before surgery that may increase the likelihood of complications or the need for a longer ICU stay—such as old age, obesity, or chronic diseases like hypertension or diabetes.