Systematic literature review on early detection of postoperative delirium in adult patients after cardiac surgery

Abstract

Background

Postoperative delirium (POD) is a cognitive decline and attention deficit that can occur in patients after cardiac surgery. Despite extensive research identifying the risk factors, POD often remains undiagnosed and untreated in medical settings. Therefore, this systematic literature review (SLR) aimed to summarize the available studies on early POD identification in patients following cardiovascular surgery.

Method

Data were obtained from Scopus, PubMed, and the Cochrane International database. The search strategy was designed to identify articles published between January 2000 and January 2024. The keywords and medical subject heading (MeSH) terms used in the search included "postoperative delirium," "cardiac surgery," "early detection," and "risk factors." Studies were included if they met the following criteria: (1) focused on adult patients undergoing cardiac surgery; (2) examined methods for the early identification or prediction of POD; and (3) provided statistical analyses or clinical outcomes related to POD. The exclusion criteria were: studies on non-cardiac surgeries, pediatric populations, or those without clear methodological details.

Results

Seven of the examined studies highlighted high-risk variables (individual characteristics, underlying diseases, and treatment methods) and typical symptoms as crucial components for early POD diagnosis. However, the diagnostic criteria and evaluation methodologies needed to be more consistent, and there was no consensus regarding the most efficient early detection approaches.

Conclusion

These findings underscore the need for standardized diagnostic criteria and evaluation methods for the early detection of POD in patients undergoing cardiovascular surgery. Evidence-based recommendations are necessary to enhance early diagnosis and treatment of POD in this population.

Introduction

Postoperative delirium (POD) is a common mental disorder observed in patients who have undergone cardiovascular surgery, with an incidence of 4.1–54.9% [1, 2]. However, this entity is also dominant in 12–52% of specimens [2]. Rising delirium is associated with enhanced death rates, cognitive weakness, longer hospital stay, and debilitated capacity in patients who undergo cardiac operations and those who are hospitalized in critical care units [3, 4]. Several studies have identified risk factors for POD in patients after cardiovascular surgery and linked these factors to early analysis of POD in these patients [5,6,7]. In real-world scenarios, POD will be combined with other similar diseases that are being misdiagnosed and, therefore, do not have proper treatment with the identified risk factors for such diseases. Established detection methods for early delirium in the case of cardiovascular disease are subject to distortions because of their low accuracy in discriminating delirium from the remaining issues, which detracts from the credibility of the illness and complexity of delirium symptoms [8, 9]. According to a study by Glumac et al., the surgery-induced inflammatory response plays a pivotal role in the mutual and interdependent mechanisms underlying the pathogenesis of both POD and postoperative cognitive dysfunction POCD. The systemic inflammation triggered by cardiac surgery has been shown to contribute to neuroinflammation, which in turn disrupts normal brain function, leading to the cognitive impairments observed in both conditions [10]. There are some commonly used scales to determine delirium, one of which is the confusion assessment method (CAM), which is widely used and enables rapid evaluation of mental state. The Delirium Observation Screening Scale (DOSS) and Delirium Rating Scale-98 are other frequently used scales. The two aforementioned methods of realizing cardiac rehabilitation are limited in implementation for patients who have undergone cardiac surgery because of certain situations, such as pharmacological anesthesia and breathing through intubation, which also includes the integration of implanted cardiac tools. One of the objectives of this systematic literature review (SLR) is to review and synthesize recent research investigations that were concerned with POD diagnosis before the patients undergo cardiovascular surgery. Thus this study aimed to detect early indicators of POD, which would enable earlier diagnosis and treatment of this condition in the pre-acute stage of cardiac disease.

Materials and methods

Search strategy

The Prescribed Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria have been followed in this SLR performed to evaluate early detection of POD among individuals who had undergone cardiovascular surgery. A systematic search strategy was developed based on professional medical advice. Our objective was to collate a fully pertinent assemblage from the current literature. To gather evidence, the international electronic databases Scopus, PubMed, and the Cochrane Library were searched. The search strategy was designed to identify articles published between January 2000 and January 2024. We use a complete set of most relevant keywords and phrases such as "delirium," "postoperative delirium," "risk factor or POD risk factors," "cardiovascular disease OR cardiovascular surgery," "early detection OR early identification," "cognitive OR cognitive disorder," " screening OR delirium screening," "symptom assessment," and relevant synonyms throughout the search (Table 1).

Table 1 PICO Framework and Search Strategy

Eligibility criteria

(a) Study Design.

• Original Studies:

  • o Observational studies (e.g., cohort, case–control, and cross-sectional studies)

  • o Randomized Controlled Trials (RCTs)

  • o Non-Randomized Controlled Trials (Non-RCTs)

• Review Articles:

  • o Systematic Reviews

  • o Meta-Analyses

  • o Narrative Reviews

(b) Language:

• Only studies published in English will be included.

(c) Population:

• Studies involving adult patients (aged 18 years and above) who have undergone cardiovascular surgery.

(d) Focus:

• Studies that focus on the early identification of POD in patients undergoing cardiovascular surgery.

(e) Relevance:

• Studies that provide insights into the risk factors, predictive models, screening methods, and early detection strategies for POD.

Exclusion Criteria:

• Studies that do not focus on early identification of POD.

• Studies involving pediatric populations.

• Studies on patients undergoing non-cardiac surgeries.

• Studies without clear methodological details.

Data extraction and statistical inspection

Three senior reviewers examined the papers that met the inclusion criteria. The titles and abstracts were thoroughly examined to determine whether the inclusion and exclusion criteria were satisfied. Data were collected through data extraction using a standardized form to obtain details on the primary author, publication year, country, study design, patient characteristics, surgical type, frequency of delirium detection assessment, and outcomes. Three reviewers (Saleh Othman, Mohammed Aziz, and Chanyanud Sriwayyapram) independently evaluated the chosen research by analyzing the titles and abstracts, and then examined the complete texts of papers that were likely relevant.

We did not use quantitative analysis (meta-analysis) in our research because of the diverse nature of the accurate assessments, outcomes, presentation methods, findings, and the limited number of individual evaluations and studies. Instead, we emphasized qualitative assessment as the primary evaluation approach.

Risk of bias

The Newcastle–Ottawa Scale (NOS) was utilized to assess the quality and potential for bias in non-randomized studies. Specifically, observational studies such as cohort and case–control studies, which are instruments to evaluate the status of nonrandomized research, were implemented to evaluate the potential for bias in the scientific quality of the studies that were presented via the evaluation process [11]. The results, comparisons, and preferences are the three important elements that constitute the NOS standards. All the studies that qualified for review were considered, and five stars were awarded to each research study.

Results

Study selection

Following the first database search, which used a predetermined set of relevant keywords and phrases, 1434 matches were identified. The initial dataset contained 942 duplicates, which were eliminated when additional analyses revealed their existence. To facilitate additional reviews and analyses, this approach ensured that the dataset was accurate and enhanced. Following this step, 492 items were considered suitable for additional examination and were subjected to the identification processes shown in Fig. 1. During the screening process, 810 studies were excluded for a variety of reasons: they were not full-text or original studies published in English; they were review letters, editorials, or systematic reviews; they were related to brain surgery or pediatric populations and other specific types of surgery; they were conference proceedings papers; or they were non-clinical studies. In total, 132 original studies met the eligibility requirements after completing the screening procedure. Among the 124 studies, four did not have their entire texts accessible, twenty-four were post hoc analyses, thirty-six did not provide quantitative data on the early identification of POD, thirty-two did not employ a validated POD scale, and twenty-eight did not prioritize the early identification of POD as a priority or secondary aim. The diagnostic approach that used a validated POD scale to detect POD in early identification was only present in eight of the retrieved studies, which represents 4.9% of the studies conducted between 2000 and 2024.

Fig. 1

Flow chart depicting systematic literature review (SLR) using the PRISMA guidelines

Characteristics of selected studies

On reviewing the seven studies that investigated the evaluation of POD, one did not use the POD diagnostic scale (Table 2). Of the selected studies, four used the CAM-ICU POD diagnosis scale and one used the Nursing Delirium Screening Scale. The remaining two studies used a mixed methodology combining the Confusion Assessment Method (CAM-ICU) with tools such as the Richmond Agitation Sedation Scale (RASS score), Montreal Cognitive Assessment and Trail Making Test Part B and Mini International Neuropsychiatric Interview. This SLR included eight distinct types of studies: seven prospective observational studies and one retrospective study (Table 1). Assessments were performed to determine the influence of a particular intervention on patient outcomes. While some studies placed greater emphasis on surgical procedures, others emphasized pharmacological therapy. The treatments varied depending on the research, with some studies placing more emphasis on surgical procedures. Furthermore, the demographic characteristics of the patient populations varied among studies over the course of the research; this was incorporated into the analysis throughout the whole process. Patients over the age of 50 years comprised the majority of participants in the study, and the average age ranged from 45 to 65 years. Patients were asked to participate in the majority of studies. In each study, approximately fifty percent of the participants were male and fifty percent were female. This indicated that sex distribution was reasonably balanced.

Table 2 The characteristics of the studies that were included

A total of 1254 patients from seven different studies were included in our analysis. Table 1 presents the outcomes of the studies conducted in China, Sweden, Poland, Greece, and the United States of America. China and the United States of America each had two studies, making them the nations with the highest number of studies.

These studies included patients who underwent various types of cardiac surgery. Five of the studies focused primarily on cardiac surgery. One study concentrated on open heart surgery, whereas another studied coronary artery bypass graft (CABG) surgery using cardiopulmonary bypass. These studies included data on the results of various cardiac surgeries and patient experiences.

Early identification of POD in patients with cardiovascular disease

Early detection of POD in patients following cardiac surgery is related to risk factors, and researchers have made efforts to uncover the risk factors associated with POD (Table 3) [20]. According to the findings of this SLR, the primary elements that contribute to the early identification of POD in patients who have undergone cardiac surgery are high-risk factors that are related to individual characteristics, underlying disorders, and treatment modalities, as well as typical symptoms that are present in the following order:

Table 3 Predictors of postoperative delirium (POD)

High-Risk factors

Individual characteristics:

The prevalence of POD is closely linked to individual characteristics. According to the guidelines set by the European Society of Anesthesiology (ESA) [3], which are grounded in evidence-based medicine and expert consensus, patients aged 65 and older are more likely to experience POD. The likelihood of developing POD-related variables increases with age. Mu et al.[17] found that age, cognitive impairment, and multiple medical conditions were independent risk factors for POD. This suggests that older patients with cognitive impairment and multiple medical conditions are more likely to develop POD. To detect and treat POD in patients with cardiovascular disease, it is vital for medical professionals to have a comprehensive understanding of these risk factors. Additionally, medicines targeting these risk factors may assist in reducing the incidence of POD in individuals who have undergone surgery. A study by Kanova et al. [19] indicated that 39 percent of people who develop post-traumatic stress disorder have a history of alcoholism. The primary reason for this is that ethanol has a depressant effect on the central nervous system. Patients cease drinking while in the hospital, leading to withdrawal syndrome. It also revealed a substantial link between sex and the occurrence of delirium, which indicates that men have a higher likelihood of experiencing POD than women, and that there is a direct correlation between the amount of education and the occurrence of POD. Signs of POD may be observed in severe instances [18].

Underlying medical conditions: Within the realm of surgical procedures, the term "underlying medical conditions" is used to describe the elements that have the potential to affect the final result of the operation. The amount of time required to complete the surgery and the particular therapies that are administered are two of these criteria. Other related variables, such as surgical method and duration, were also included in this group [12, 21]. Those attending to the concerned meticulously must consider these features in light of the threats associated with surgery and its aftereffects. Mu et al. [17] This association became much clearer when the researchers found that the number of surgical operations performed during the one hour service time period was inversely proportional to the incidence of POD. The conclusion seems to be that the number of cases of medical emergencies increases correspondingly with operation duration.

An analysis of surgery conducted by Hughs et al. [22] established that surgical revascularization procedures had significantly lower rates of POD occurrence than other large vascular operations such as thoracotomy. Surgical operations for aortic dissection, coronary artery bypass grafting, heart transplantation, abdominal incision, and major vascular surgery would have a higher incidence of POD than other surgical procedures. Besides, the statisticians broke down the surgical POD rate as a function of the conditions under which they were applied. However, Kazmierski et al. pointed out that the proportion of patients who developed POD was as high as 36.3% among those undergoing coronary bypass surgery, 32.5% among those with aortic dissection, 25.7% in cases of heart transplantation, and 16.3% among those receiving thoracotomy [13].

Treatment procedures: Admission into the intensive care unit, immobilization (to use protective restraints), postsurgical pain, sleep disturbances, endotracheal intubation, blood transfusions, decrease in blood oxygen levels (hypoxemia), and the application of vasoactive drugs are risk factors for the onset of POD [13, 24]. Lower use of vasoactive drugs, better pain management, or other means of decreasing the number of patients with POD who have undergone cardiac surgery may help achieve the target. Nurses and doctors can improve the prediction and management of delirium by increasing their understanding of the early factors that could be the starting point for such a disease. Arenson et al. [21] found that 14.7% of 1010 patients who underwent cardiac surgery presented difficulty in breathing after surgery, which they termed POD. The potential for the development of particular disorders, such as receiving large amounts of blood products in the transfusion and the use of intubation exceeding twenty-four hours are factors that may affect the condition [14], stroke, renal failure, prolonged cross-clamp time [16], or transient ischemic attack [18]. While this is not entirely so, the problem may arise from undertreated patients after the operation or incorrect use of certain drugs such as anticholinergics, opioid narcotic analgesics, and benzodiazepine sedatives [15].

Typical symptoms

Attentional disturbances, cognitive difficulties, fluctuating consciousness, sleeplessness, wide unusual perceptions, and hallucinations are a few of the possible clinical signs of POD. POD can trigger dysfunctional emotional reactions in victims manifesting as anxiety, impatience, and fading emotions. POD affects people in different ways; however, it usually does not involve motor skills that may include hyperactivity, hypoactivity, or even pendulum-like fluctuations between these two types. Acute delirium agitation manifests as a rebound of mental activity and body motility. These symptoms may vary and include obvious ones such as trouble calming down, emotional instability, restlessness, and irritation. Among the possible signs exhibited are hallucinations, deluded thoughts, and violent behavior [13]. This type of delirium presents a higher risk to patients and is clearly recognizable but may also be susceptible to misdiagnosis. Hyperactive delirium in critical care settings is sometimes misidentified as regular agitation, resulting in incorrect use of sedatives, which might worsen the situation. Patients with hypoactive delirium have an elevated risk of death and require specific therapies.

Mixed delirium is characterized by the fact that it displays symptoms of both hyperactive and hypoactive delirium. This is a characteristic feature of mixed delirium, characterized by intervals of thinking and activity levels that typically function; however, these periods are intermittent and occur regularly. Mixed delirium is difficult to diagnose and treat. Besides, it manifests itself in a variety of symptoms. It is of the utmost importance to identify and treat a specific type of delirium in individuals to improve the results for patients and reduce the severity of the repercussions.

Several studies have highlighted the necessity of recognizing the typical symptoms of POD to facilitate early identification and immediate initiation of treatment. Arenson et al. [21] that 14.7% of patients who underwent cardiac surgery, which is an indication for POD. Identifying POD at an early stage is challenging because of pain, pharmacological side effects, or metabolic abnormalities. Therefore, it is critical to identify the typical symptoms and forms of delirium in patients after cardiac surgery to diagnose delirium early and provide appropriate care. Practitioners in the medical field need to be vigilant when assessing patients for delirium symptoms, because prompt intervention may improve patient outcomes and reduce the likelihood of unfavorable events.

Risk of bias

Table 4 illustrates that there was a comparable risk of bias across all different areas evaluated, which is clear when looking at the data of all eight studies taken together. Specifically, A certain amount of robustness in the procedures employed for participant selection was indicated by a reasonably low risk of bias within the parameters of the selection domains. However, in our study, a higher risk of bias was recorded within the comparability elements among the selected studies, which is highly suggestive of potential limitations in the ability to compare study among different studies. Interestingly, the risk of bias in result confirmation was constant across all eight studies. This finding suggests a consistent degree of trustworthiness in the measurement and reporting of outcomes across various studies.

Table 4 A assessment performed by the NOS to determine the likelihood of bias

Discussion

Overall findings

Early identification of POD in patients after heart surgery is imperative to prevent negative consequences. Researchers have been involved in identifying the major risk factors for POD from an early stage to achieve early diagnosis of this disease. Based on the results of this SLR, high-risk indicators will be essential components of early alerts on POD for patients after undergoing heart surgery. These factors are essentially personal features, psychological conditions, and treatment approaches. Personal features such as age, sex, education level, and medical history influence susceptibility to delirium. Elderly individuals are particularly vulnerable to age-related brain changes. Sex differences and higher education levels may also play a role. Additionally, pre-existing medical conditions, such as cardiovascular disease and alcoholism, can increase the risk. Psychological conditions, such as anxiety, depression, and post-traumatic stress disorder (PTSD), contribute to delirium risk by exacerbating stress responses and neuroinflammation. Patients with trauma or PTSD are particularly susceptible. Treatment methods such as surgical procedures and anesthesia affect the risk of delirium. Cardiac surgery involving bypass and prolonged anesthesia can trigger neuroinflammatory responses. The choice of anesthetic and postoperative care also affect susceptibility. Delirium, as a rule, is caused by age among the different individual factors that predispose an individual to delirium. According to research, the chance of people over the age of 65 years having delirium after the operation was higher. Intellectual disability, particularly as an independent risk factor for POD, is recognized as a marker of mental state. Another risk factor that increases the likelihood of POD is the presence of other medical conditions. Sex and educational ranking are crucial factors related to the likelihood that men and affected group of alcoholics are the most vulnerable. The role of POD is accentuated by considering the patient's medical history and other conditions, along with the length of the procedure and the techniques used by the surgeon [24, 33]. Specific surgical approaches such as CABG have been found to be related to a disproportionate rate of postoperative amnesia. The duration of surgery has been demonstrated to be not only the decisive factor in postoperative complications but also significantly contributes to the overall safety of surgical procedures [21, 25]. Finally, the evolution of POD is probably influenced by postoperative interventions after heart surgeries. The services offered by the hospital frequently include continuous hospitalization in the intensive care unit, strict immobilization of the affected limb, and pain control throughout the postoperative period. Pain medications, which can be considered vasoactive medicines that induce inadequate pain control, have been shown to play a significant role in the onset of delirious conditions after surgery. Moreover, pharmacological deficits in actions or common signs of POD include cognitive dysfunction that involves the patient's awareness, direction, and attention, and can be in the form of hyperactive, hypoactive, or mixed delirium. Hyperactive delirium is enriched with an amped cognitive processes and marked agitation, whereas in the hypoactive state, mental activity is diminished and delayed responses to speech or body movements are sometimes displayed. To illustrate this, one must point out mixed delirium, in which the patient goes back and forth between the hyperactive and hypoactive phases [26].

Healthcare personnel must act quickly to identify early stage POD symptoms and risk factors observed in patients after ECS to avoid the progression of delirium. If factors that lead to the development of surgery-related delirium and poor outcomes are identified and dealt with by healthcare providers, they are empowered to enhance the quality of care they already offer to such patients.

Recommendations

Preventive approaches without medications

POD prevention in patients undergoing cardiac surgery is of prime importance because advances made in various studies indicate that different strategies reduce POD occurrence. Employing a multifaceted treatment in early mobilization together with proper pain management, reduction in sedatives, proper hydration and food intake, and treatment of concurrent disorders such as dementia, depression, and sleeping problems has been proven to decrease the chances of POD in patients who undergo surgery [27]. Adopting alternative strategies that do not correlate with medications, such as cognitive stimulation methods, patient communication techniques, and family participation, may prevent POD. Research conducted by Oh et al. [28] found that the use of multicomponent treatments, including distractions such as picture testimonies, pictures, and pictures taken during table visits, could be of high significance in the prevention of POD in elderly surgical patients. As mentioned above, solutions tend to adopt a strategy that is usually a mix of various methods, such as universal screening for the most probable delirium risk, early mobility, and improved communication among various health professionals involved in the treatment process. One cause of the increase in the POD rate might be the pharmacotherapy of patients in risk groups with antipsychotic drugs, such as dexmedetomidine, melatonin, and other antipsychotic medications. [29]. However, weighing the benefits of these medications or, conversely, the potential dangers they carry is of prime importance in order to adjust the treatment plan to the patient’s individual risk factors and needs [30, 31]. Young et al.[32] stated that it might be helpful to adopt broad preventive measures operating at the presurgical stages that could reduce POD incidence in patients after cardiac surgery. Thus, it is necessary to employ a multifaceted and proactive approach to avoid POD in surgical cases to obtain desirable outcomes, lower healthcare costs, and greater quality of care for these patients. Evidence-based treatments and tailored treatment plans adopted by medical professionals will decrease the risk of POD; hence, the expected outcomes of POD will improve.

The medication prevention measures

Due to the absence of substantial clinical trial data indicating that pharmaceuticals or combined non-drug preventive strategies may reduce the occurrence and duration of Parkinson disease in cardiovascular diseases, it is not recommended to consistently use medications to prevent the onset of Parkinson disease. It is because of the fact that there is a certain amount of disagreement around the subject that this is the case [5, 6]. However, there are circumstances in which one can be rooted. The administration of benzodiazepines is necessary because of the severity of the condition. For instance, patients who had excessive worry or anxiety before surgery, as well as those who had been using benzodiazepines for a considerable amount of time prior to surgery, should use them with caution [13].

In general, future research should focus on the following points. First, to examine the possibility that patients with cardiovascular illness may not report POD as much as they might be due to differences in diagnostic criteria or evaluation techniques across a number of different studies. Second, to investigate the differences in defining and diagnosing delirium as well as the influence of these differences on the reported prevalence rates. Third, to examine the degree of variation in outcomes observed after surgical delirium in individuals with cardiovascular conditions. It is also important to investigate both the short- and long-term impacts and implications on cognitive function, mortality, functional recovery, and healthcare usage.

Strengths and limitations

Our systematic review had several strengths that bolstered its credibility and reliability. By encompassing a broad range of databases including Scopus, PubMed, and the Cochrane Library, we ensured a thorough and replicable search strategy. The inclusion criteria were meticulously set, focusing on studies published in English that included adult patients who underwent cardiovascular surgeries. This study enhanced the relevance of our findings to this specific population. Additionally, our data extraction process was rigorous and involved three senior reviewers to maintain objectivity and consistency. The inclusion of a qualitative assessment allowed us to delve deeper into the varied nature of the literature, and the use of the Newcastle–Ottawa Scale provided a robust tool for evaluating the risk of bias across the included studies.

However, despite these strengths, our review has some limitations. One notable constraint is language restrictions, as we only included studies published in English. This limitation introduces a potential publication bias, as relevant studies published in other languages may have been excluded, thereby narrowing the scope of our review.

The heterogeneity of the reviewed studies also presented a challenge. Variations in the study design, population characteristics, diagnostic criteria, and outcome measures have made it difficult to draw direct comparisons across studies. This diversity not only complicated our analysis, but also prevented us from conducting a meta-analysis, which could have provided a more quantitative synthesis of the findings. The absence of a meta-analysis means that our conclusions are based on a qualitative synthesis, which, while comprehensive, lacks the statistical precision that a meta-analysis can offer.

Our review included all types of cardiac surgeries that introduced heterogeneity into the patient population. Different types of cardiac surgery, such as CABG and valve surgery, carry varying levels of risk for the development of POD.

Another limitation lies in the tools used to assess the study quality. Although the Newcastle–Ottawa Scale is a widely recognized instrument for evaluating the risk of bias in observational studies, it has limitations. The scale may not fully capture the complexities of different study designs, and the subjective nature of some criteria may introduce variability into the scoring process.

Although extensive, the scope of the reviewed literature may still have gaps. Despite our thorough search strategy, there is always the possibility that some relevant studies were not identified, either because of database limitations or inherent challenges in creating a comprehensive search strategy. Furthermore, by focusing exclusively on adult patients undergoing cardiovascular surgery, we may have excluded findings applicable to other patient groups or broader contexts.

Finally, the temporal and geographical diversity of the studies included in our review adds another layer of complexity. These studies spanned several years and came from various regions, each with its own healthcare practices, infrastructure, and cultural considerations. These factors could influence the applicability of the findings and introduce variability, which must be carefully considered when interpreting the results.

Conclusions

According to the majority of patients who have had cardiovascular surgery, extended sedation and intubation are necessary in order to satisfy the criteria of the condition and the treatment. This characteristic is typically observed in patients who undergo cardiovascular surgery.

In this systematic literature review, the early and primary factors that contribute to the early identification of postoperative complications (POD) in patients who have undergone cardiac surgery were identified as high-risk factors. These factors are related to (individual characteristics, underlying disorders, and treatment modalities), and are associated with typical symptoms. Several relevant strategies have been proposed for this purpose. This research also demonstrates that the training of medical professionals in understanding delirium should be enhanced, as well as the accurate application of delirium evaluation tools to improve the accuracy of POD monitoring in patients. Increase the effectiveness of therapy for POD in patients and implement effective measures for the prevention of POD in patients who have cardiovascular disease.

Future research should focus on exploring discrepancies in POD reporting among cardiovascular patients; investigating variations in defining and diagnosing delirium; and assessing outcomes after surgical delirium on cognitive function, mortality, functional recovery, and healthcare usage from both short- and long-term perspectives.