LITHUANIAN UNIVERSITY OF HEALTH SCIENCES
MEDICAL ACADEMYFACULTY OF NURSING
DEPARTMENT OF NURSING AND CARE
FELICIA MAMLE PARTEY
THE INFLUENCE OF POSTOPERATIVE DELIRIUM ON
POST-OPERATIVE OUTCOMES AFTER CARDIAC SURGERY AND ITS
RELATION WITH SOCIODEMOGRAPHIC FACTORS
The graduate thesis of the master‘s degree study programme “Advance Nursing Practice“
(State Code 6211GX008)
Tutor of the graduate thesis PhD, MD JUDITA ANDREJAITIENE
TABLE OF CONTENTS
1. ABSTRACT ________________________________________________________________ 3 2. ABBREVIATIONS ___________________________________________________________ 4 3. INTRODUCTION ____________________________________________________________ 5 4. LITERATURE REVIEW ______________________________________________________ 8 4.1 Definition and description of postoperative delirium ________________________________ 8 4.2. Prevention postoperative delirium ______________________________________________ 9 4.3. Risk Factors of Postoperative Delirium following cardiac surgery ___________________ 11 4.3.1. Modifiable Risk Factors _______________________________________________ 11 4.3.2. Non modifiable Risk factors _______________________________________________ 12 4.3.3. Preoperative risks factors ______________________________________________ 12 4.3.4. Intraoperative risks factors _____________________________________________ 13 4.3.5. Postoperative factors _________________________________________________ 13 4.4. Incidences of postoperative delirium after cardiac surgery ________________________ 14 4.5. Outcomes related to POD following cardiac surgery ____________________________ 15 4.6. The relation between sociodemographic factors postoperative delirium after cardiac surgery.
15
1. ABSTRACT
Felicia Mamle Partey. The influence of postoperative delirium on post-operative outcomes after cardiac surgery and its relation with sociodemographic factors
The tutor – MD, PhD Judita Andrejaitienė. Lithuanian University of Health Sciences, Faculty of Medicine, Department of Cardiothoracic and Vascular Surgery, Lithuania.
Introduction: Patients who undergo cardiac surgery have an increased risk of delirium, which is associated with many negative consequences.
Aim of the study: to determine the incidence of postoperative delirium after cardiac surgery, to find its relation with sociodemographic factors and influence on post-operative outcomes.
Methods: Study was conducted between 2nd of December 2020 and 28th of January 2021 at Hospital of Lithuanian University of Health Sciences Kaunas Clinics. The study was approved by the Ethics Committee (ongoing research „Predisponuojančių veiksnių išaiškinimas kognityvinių funkcijų sutrikimo atsiradimui pacientams, kuriems atliekamos operacijos naudojant dirbtinę kraujo apytaką“ BE-2-3 2017.04.12 Lietuvos sveikatos mokslų universitetinė ligoninė Kauno klinikos; Širdies, krūtinės ir kraujagyslių chirurgijos klinika). Data on 90 patients after elective cardiac surgery on cardiopulmonary bypass (CPB) was analysed retrospectively. Subjects were divided into two groups, with postoperative delirium (I group) and non-delirious patients (II group). POD was evaluated using The Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) delirium assessment tool. The data are presented as the mean and the standard deviation (M(SD). Differences were considered as statistically significant at p<0,05.
2. ABBREVIATIONS
3D-CAM - 3-Minute Diagnostic Interview for Confusion Assessment Method CABG - Coronary Artery Bypass Graft
CAM - Confusion Assessment Method CPB - Cardiac Pulmonary Bypass
DSM-5 - Diagnostic and Statistical Manual of Mental Disorders V ICDSC - Intensive Care Delirium Screening Checklist
ICU - Intensive Care Unit POD - Post-Operative Delirium
RASS - Richmond Agitation and Sedation Scale VAS - Visual Analogue Scale
3. INTRODUCTION
Cardiac conditions have become prevalent among older populations worldwide [1]. This has resulted in increased number of cardiac surgeries performed annually. Studies show, that most older populations that undergo cardiac surgery experience postoperative delirium (POD) which is now a major epidemiologic and clinical problem [2]. In addition, POD after cardiac surgery has become one of the major challenges to medicine as a result of demographic changes [2]. Older patients who go through cardiac surgery have high risk of developing delirium POD is a type of delirium that occurs in patients following surgical procedures and anesthesia [3]. POD is a common mental disorder among hospitalized patients’ especially elderly patients who have undergone cardiac surgery for the first time. POD after cardiac surgery is related to increased morbidity and mortality as well as lengthened stay in both the intensive care unit and the hospital which leads to poor outcomes and increased health care costs [4]. Delirium after cardiac surgery is a common complication in cardiovascular intensive care units.
Historically, the first person to be diagnosed of POD as a complication following cardiac surgery was Gilman in the year 1965 [5]. There are different types of POD which varies in every patient. Patients may exhibit hyperactive, hypoactive, or mixed hyper-hypoactive cognitive and motor states. Clinical manifestations may also depend on the type of POD. Hyperactive patients may present psychomotor activity, such as rapid speech, irritability, and restlessness and are often disruptive, time-consuming, and harmful to staff [6]. They are, therefore, more readily identified and treated. Hypoactive patients, by contrast, typically show a calm appearance combined with inattention, decreased mobility, and have difficulty answering simple questions about orientation [6]. Hypoactive delirium may be misdiagnosed as depression or fatigue and may be due to acute terminal illness [6].
POD affects nearly 30% of cardiac surgery patients, despite the fact that the reported incidences are inconsistent [9]. In one study, POD after cardiac surgery was diagnosed in 26%–52% of patients, while other studies found 70% according to their respective methodologies [9]. In patients older than 60 years, the reported incidence is similar – between 30% and 52%. Factors identified as main risks factors of POD after cardiac surgery include: older age, pre-operative cognitive decline, atrial fibrillation, previous delirium and also some neurological disease conditions and co-morbidities [9].
After surgery, examining and identifying delirium remains variable, because of inconsistent cause and high frequency of hypoactive indications [9, 10]. Postoperative confusion states are less likely to be detected in major neurological complications. Furthermore, differences in symptoms overlapping with dementia and natural changes of aging brain makes it more difficult to identify this complication in an advanced age population [11].
It was reported that, the cost of delirium is over $164 billion (2011) per year in the United States and over $182 billion (2011) per year in European countries as a whole [12]. Also studies have shown that the incidence of POD in patients undergoing cardiac surgery ranges from 20 to 50%, with patients with advanced age having the greatest risk [12]. Detection of delirium and its risk factors can be reduced through targeted interventions and risk factors reduction [13].
In Lithuania, research on POD is advancing. A recent study conducted in Kaunas hospital involving older surgical patients associated decline in cognitive activity in the first year of discharge to postoperative delirium [13]. Other studies have reported similar outcomes citing a higher likelihood of risks associated with postoperative complications, long stay in hospital intensive care units, elevated number of readmissions, poorer cognitive and functional outcomes, and higher death rates [14, 15].
THE AIM
Aim of this study - to determine the potential risks factors, incidence and evaluating the clinical outcomes of postoperative delirium in older adults following cardiac surgery.
OBJECTIVES OF STUDY
Specific objectives of the study included:
1. To determine the potential risks factors of postoperative delirium in older adults; 2. To identify incidence of postoperative delirium in older adults;
4. LITERATURE REVIEW
This section reviews relevant scholarly literature in postoperative delirium following cardiac surgery in older adults. The aim is to understand the risk factors, incidence and outcome associated with postoperative delirium. Based on the interest of the study, the search criterion was based on articles that are mostly centered on the risks factors, incidence and outcome of postoperative delirium. A combination of keywords such as “postoperative delirium”; “postoperative delirium” AND “cardiac surgery; “AND “postoperative delirium” AND “postoperative outcome” AND postoperative delirium “AND” “sociodemographic factors” etc. was used to search for relevant articles from Scopus, Google Scholar and PubMed. The search was narrowed to original research or review articles published within the past 10 years. Literature were filtered by reading abstracts and grouping according to their relevance to understanding postoperative delirium in older adults following cardiac surgery and the risks factors, incidence and outcomes associated with the medical condition.
4.1 Definition and description of postoperative delirium
Delirium is a neuropsychiatric syndrome indicated in changes in cognitive functions [17]. According to the Diagnostic and Statistical Manual of Mental Disorders V, postoperative delirium is defined as an acute onset fluctuating change in mental status characterized by a reduced awareness of the environment and disturbance of attention [17].
The key features of delirium according to the Diagnostic and Statistical Manual of Mental Disorders V are represented by disturbance in attention (that is reduced ability to direct, focus, sustain, and shift attention) and awareness [18]. In addition, changes in cognition (examples: memory deficit, disorientation, language disturbance, perceptual disturbance) that is not better accounted for by a preexisting, established, or evolving dementia may occur. A previous study associated postoperative delirium in older patients undergoing cardiac surgery with declining postoperative cerebral oxygen saturation [18]. The disturbances associated with postoperative delirium begin over a short period (usually hours to days) and tends to fluctuate during the course of the day [19].
[19]. Postoperative delirium after a CABG Surgery affects individuals who are older, more frequently male, and have preexisting cerebral disease, particularly dementia [19].
Postoperative delirium can therefore be described as a usual and severe complication after cardiac surgery. Several studies have discovered that between 10% to 60% patients has an elevated risk of developing post delirium following cardiac surgery that is related with poor outcomes [20]. The type of postoperative delirium varies and patients may exhibit hyperactive, hypoactive, or mixed hyper-hypoactive cognitive and motor states [20]. Hyperactive patients present psychomotor activity, such as rapid speech, irritability, and restlessness and are often disruptive, time-consuming, and harmful to staff. They are, therefore, more readily identified and treated. Hypoactive patients, by contrast, typically show a calm appearance combined with inattention, decreased mobility, and have difficulty answering simple questions about orientation [21]. Hypoactive delirium may be misdiagnosed as depression or fatigue and may be due to acute terminal illness [21].
4.2. Prevention postoperative delirium
On the prevention of postoperative delirium, only limited studies have attempted this. However, like most medical conditions a pervious study conducted, asserts that early detection of postoperative delirium is very significant as a means to improving the safety of patients and providing important leads in the understanding of the factors and causes of delirious behavior [22]. A recent systematic review with meta-analysis and trial sequential analysis of randomized clinical trials suggested sleep and circadian health may be a useful way to prevent the development of this medical condition [22].
A recent paper published in the Journal of Clinical Anesthesia also provided meta-analytic evidence that dexmedetomidine could be the most viable and effective sedative agent or perioperative anesthetics to reduce postoperative delirium [23]. This was also confirmed by a recent study when they systematically reviewed trials focusing on prevention and treatment of delirium after cardiac surgery [24]. According recent literature reviewed, pharmacological prevention of delirium is not recommended because its effectiveness is not proven. However, the study approves identifying and modifying risk factors of postoperative delirium [25].
nursing care, delirium can be prevented in 30%-40% of patients at risk especially in older adults. Nurses play a vital role in preventing delirium in older adults and with the provision of effective nursing care, incidence, severity, and duration of postoperative delirium can be reduced and also these interventions are have been evidenced as cost effective.(27)
In a recent study finding, it was revealed that nurses can implement a multicomponent nursing intervention guidelines were basically made for identifying risk factors of delirium [28]. According to the author, the guidelines were grouped into four. These guidelines are firstly orientation and activity intervention guidelines. This states that the nurse should be called by their names, board with names of the care-team members and day’s schedule, placement of familiar items, effective communication. Secondly the author encouraged early mobilization intervention after surgery thus the nurse should ensure active range-of-motion exercises, avoidance of immobilizing equipment (bladder catheters, physical restraints). Thirdly, Visual aids and hearing intervention guidelines: here the nurse should provide patient with their Visual aids (glasses, lenses), hearing aids, adaptive equipment (large-print books, fluorescent tape on call bell), portable amplifying devices when they regain consciousness and lastly, Sleep enhancement intervention thus the nurse should use unit-wide noise-reduction strategies, provide light reduction, avoid medical procedures at night and also provide relaxation tape or music for patients. Also nurses should correct hypoxia, hypotension, hypertension, and anemia, ensure adequate enteral hydration and nutrition, suspend unnecessary drugs, regulation of bowel and bladder function, treatment of pain, and minimize the use of invasive tools [29].
Another literature reviewed also stated that preventing of delirium in an older adults, nurses should assessing all patients who are at risks of delirium such as older adults eg.65 years and above, patients who have history of dementia, patients who has undergone major surgeries and have been in the ICU up to 48 hours postoperatively [29]. Nurse should screen and examine all patients using the Standard Assessment Tool on admission and on every shift for change in cognition or level of consciousness.
4.3. Risk Factors of Postoperative Delirium following cardiac surgery
A number of risk factors have been identified from numerous studies that can increase an individual’s risk of developing delirium after cardiac surgery. The scholarship on postoperative delirium reveals that about 20% to 25% cardiac surgery patients develop the condition [30]. The literature also reveals that the risk of postoperative delirium after cardiac surgery is comparatively higher in patients who have valve replacement than in patients who have bypass surgery [30, 31]. Although the mechanism of delirium has not been interpreted, there has been important interpretation of related patient risk factors [31]. Some of these may be considered as existing vulnerabilities or predisposing factors, and others precipitating factors [31, 32]. Some of the predisposing factors are age, male gender, visual and hearing impairment, cognitive impairment, dehydration, drugs and alcoholism, existence of another or multiple conditions such as dementia and post stroke patients or surgeries [32].
Few studies have reported prevalence rates of predisposing and precipitating factors of delirium in community-dwelling old patients [32]. Results from the studies are not homogeneous. In one study, infections, metabolic disturbances and adverse drug effects were the most frequent triggers of delirium [33], while in another study metabolic disturbances and acute cardiovascular diseases were identified as the triggers of delirium [33].
In another study, the following were identified as the precipitating factors of postoperative delirium: surgery or multiple (diagnostic) procedures; admission to ICU; drugs such as sedative hypnotics, benzodiazepines, opioids, anticholinergic drugs; treatment with multiple drugs, alcohol or drug withdrawal; intercurrent illness (examples: infections, iatrogenic complications, severe acute illness, metabolic, derangements, fever or hypothermia, shock, hypoxia, anemia, dehydration, low serum albumin and inadequate nutritional status); primary neurological disease (such as stroke, intracranial hemorrhage, meningitis and encephalitis) pain, use of physical restraints, use of urinary catheters, emotional stress, prolonged sleep deprivation etc. [33, 34].
Causes of post-operative delirium after cardiac surgery can offend are traced to one or more contributing factors from the period of admission to the postoperative period. These periods are grouped into preoperative, intraoperative, postoperative risk factors. These factors can be classified as modifiable and non-modifiable factors [35].
4.3.1. Modifiable Risk Factors
• fluid fasting time >6 hours, blood biochemistry abnormalities (such as sodium, potassium, glycaemia, urea nitrogen, and serum albumin),
• medications (such as opioids, analgesics, anticholinergics drugs, narcotic), • Delayed ambulation, insufficient nutritional status [36],
• Acute neurological conditions such as( acute stroke, intracranial hemorrhage, meningitis and encephalitis),
• type of surgery,
• Intercurrent illness (examples infections, iatrogenic complications, severe acute illness, metabolic, derangements, fever or hypothermia, shock, hypoxia, anemia, dehydration, low serum albumin and inadequate nutritional status),
• environment( for example admission to an intensive care unit) [37]
4.3.2. Non modifiable Risk factors
Non-modifiable risk factors of postoperative delirium include: blood loss, advanced age >70 years, type of surgery (cardiac aortic aneurysm, orthopedic, hip replacement, intra-abdominal and intra thoracic,), genetic profile (example: phenotype), multiple comorbidities, psychiatric and neurological disorders (example: presence of dementia), illicit drug abuse, alcoholism, Dementia or cognitive impairment, History of delirium, stroke, neurological disease, falls or gait disorder, multiple comorbidities, Chronic renal or hepatic disease [38].
4.3.3. Preoperative risks factors
From a study, preoperative laboratory findings were associated with a higher incidence of postoperative delirium. The findings showed that low preoperative albumin levels as a result of malnutrition and electrolyte disturbances due to dehydration result in an increased preoperative risk factor [39]. It was also revealed that preoperative anemia aside that patients on preoperative anticholinergic, antihistaminic, and antipsychotic medications highly at risks of postoperative delirium, excessive alcohol intake was identified as an individual risk factor, frequent sedatives intake during preoperative period. Another risk factor is a preexisting impaired cognitive status or condition such as dementia [40].
Previous publications have describe a large number of risk factors such as advanced age, dementia, hearing and visual impairment, diabetes mellitus, impaired left ventricular ejection fraction, electrolyte derangement, history of hypertension, alcoholism, smoking, severity of illness, pre-existing pulmonary disease, history of cerebrovascular disease, longer operation time, time on cardiopulmonary bypass (CPB), high perioperative transfusion requirement, postoperative hypertension, atrial fibrillation, postoperative tachycardia, high blood urea level, and pneumonia
4.3.4. Intraoperative risks factors
The duration and type of the surgeries can be associated with the occurrence of delirium. This is because the duration of the surgery is mostly based on the complexity of the procedure. As the complexity of the surgical procedure increases, the risks for postoperative delirium also increased during complex procedures such as mitral and aortic valve replacement, there is a high release of microemboli which causes neurological injuries to the patient [42].
Intraoperative medications have been identified as a risk factor of delirium [42]. These medications include both fentanyl and ketamine. However, diazepam has inconclusive results [38]. The use of high-dose steroids to prevent the systematic inflammatory response during bypass has also been shown in two recent major trials not to have any impact on the incidence or duration of delirium after cardiac surgery [43].
Also, several studies has have evidenced that case of postoperative delirium commonly reported in surgical procedures that required replacement of both mitral and aortic valves. Procedures without cardiopulmonary bypass can decrease the incidence of psychiatric and neurological complications post operatively.
4.3.5. Postoperative factors
According to a study, postoperative risk factors is related with in-hospital delirium after cardiac surgery which include postoperative stroke or transient ischemic attack, long duration on ventilator, age 65 years or older, concomitant coronary artery bypass grafting and valve surgery, postoperative blood product transfusion, and postoperative renal insufficiency were identified as risk factors [44]. Postoperative medications can also contribute to delirium in the cardiac surgical ICU. Age-related changes in absorption, distribution, and renal excretion all affects drug
It has been revealed that patients who demonstrate a low cardiac output during the first several postoperative days experienced hallucinations. However, these symptoms happen when there is a rapid rise in cardiac output and also the use of an intra-aortic balloon pump (IABP) correspond with an increased risk of delirium. This is likely to associate with the increased use of neuroleptics and narcotics to sedate patients with an IABP [45].
4.4. Incidences of postoperative delirium after cardiac surgery
The incidence of postoperative delirium has been reported in many literatures and it varies from 3.3% to 77%, depending on the patient population [46]. According to pervious data, the incidence of postoperative delirium in elderly patients undergoing major surgeries are quite variable, ranging from 5-15% in patients undergoing general anesthesia to as high as 62% in hip fracture patients and 73% in elderly cardiac surgery patients. In surgeries requiring postoperative intensive care, the incidence of postoperative delirium was found to be 44% [46].
The incidence of POD according to DSM-IV criteria was 16.3% (95% confidence interval: 13.5–19.6). Multivariate stepwise logistic regression analysis disclosed that advanced age, preoperative cognitive impairment, an ongoing episode of major depression, anemia, atrial fibrillation, prolonged intubation and postoperative hypoxia were independently related with delirium after cardiac surgery [47].
According to past data, the incidence of delirium after major surgery such as cardiovascular surgery is 30 % to 73 %. Older age, history of psychiatric disorder and excessive blood loss volume are mostly reported risk factors for POD [47]. Furthermore, another study also identified that the type of surgery is also associated with the influence of the incidence of delirium [48]. Valve surgery is related to a 70% increase rate in delirium as compared to coronary artery bypass surgery (CABG). Studies have shown that delirium rates up to 90% can be expected in the replacement of both the mitral and aortic valves [47, 48].
However numerous studies have suggested that avoiding cardiopulmonary bypass (CPB) altogether decreases the incidence of psychiatric and neurological complications postoperatively; no difference has been found between on-pump and off-pump CABG [48]. According to a study,
According to the study, overall, 30% to 60% of all cases of delirium are thought to remain undiagnosed [49].
4.5. Outcomes related to POD following cardiac surgery
A number of scholarships on POD after cardiac surgery establish linkages to adverse outcomes. In Lithuania, a study involving older surgical patients associated decline in cognitive activity in the first year of discharge to POD after cardiac surgery [49]. Other studies have reported similar outcomes citing a higher likelihood of risks associated with postoperative complications, long stay in hospital intensive care units, elevated number of readmission, poorer cognitive and functional outcomes, and higher death rates [49, 50].
In a single-center, prospective cohort study involving 197 patients undergoing coronary artery bypass grafting or valve replacement, no significant differences where observed in the cognitive functioning of patients with and without POD. However, the authors reported that cardiac surgical patients with condition of postoperative delirium were more likely to experience self-reported problems in affective (depression and anxiety) functioning (odds ratio, 4.41; 95% confidence interval, 1.51-12.92; P<0.01) [36].
A paper published in the American Journal of Critical Care, the authors also showed that in comparison with surgical patients without POD, the 25% patients who experienced this medical condition had statistically significant longer stays in hospital, experienced greater occurrences of falls [50]. In addition, the authors observed that physical therapy and home nursing care may be continued for such patients even when discharged home [50].
4.6. The relation between sociodemographic factors postoperative delirium
after cardiac surgery.
According to numerous literatures reviewed, older age was which ranges from 60 years and above was statistically significant sociodemographic factor for the development of POD following cardiac surgery. In a recent study, the prevalence of POD after cardiac surgery shown between 1% in patients with 55 years of age and 14% in patients older than 85 years [51].
A previous study indicated that education has negative impact on severity of delirium, according to the author, high level of educational, decreases the severity of delirium (z-value= −1.868 p= 0.062) [53]. Meanwhile according to recent study, it was showed that there was no evidence that gender or education contributes to the development of POD [54]. Furthermore numerous literature reviewed have showed that gender, race or marital status was not statistically significant factor for the pathogenesis of POD after cardiac surgery.
4.7. Diagnosing POD
Even though DSM-5 criteria is standard references for the diagnosis of delirium, several methods have been made for proper assessment and confirmation of manifestations of delirium in ICU patients according to the DSM-5 criteria. These methods are the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC) [55]. These scales are used to assess confusions in ICU patients and have been widely used in worldwide [55, 56].
In a prospective diagnostic study conducted in Berlin, Germany, the authors confirmed 3D-CAM was effective for detecting POD during recovery [57]. The authors mentioned this method as user friendly requiring low training [58]. A recent literature has shown that despite the fact that the original CAM is mostly used in observing and monitoring delirium, mechanically ventilated patients have been ruled out from CAM investigations to date [59].
Using the diagnostic criteria according to ICD-10 requires the presence of these five clinical features: impaired consciousness and attention, global disturbance of cognition as well as psychomotor, sleep and emotional disturbances [60].
Furthermore a study has stated that delirium can be diagnosed by the following cognitive manifestation
• orientation (impaired awareness of oneself and one’s surroundings in terms of time, place and person);
• memory (impaired ability to learn new information or to recall previously learned information);
• language and thought (disturbance in the comprehension and/or expression of speech as well as abnormalities in the flow and connectivity of thought);
5. ORGANISATION AND METHODOLOGY OF A RESEARCH
Patients and methods
A retrospective study was conducted on 2nd of December 2020 until 28th of January 2021 at Lithuanian University of Health Sciences Hospital in Kaunas Clinics. The study was approved by the Ethics Committee (ongoing research „Predisponuojančių veiksnių išaiškinimas kognityvinių funkcijų sutrikimo atsiradimui pacientams, kuriems atliekamos operacijos naudojant dirbtinę kraujo apytaką“ BE-2-3 2017.04.12 Lietuvos sveikatos mokslų universitetinė ligoninė Kauno klinikos; Širdies, krūtinės ir kraujagyslių chirurgijos klinika).
The patients included in the study were any patients who have undergone elective cardiac surgery on cardiopulmonary bypass (CPB). Ninety patients were enrolled in the study. Patients were divided into two groups, which are patients with postoperative delirium (I group) and non-delirious patients (II group).
Data collection and delirium screening
Patients were screened for postoperative delirium by using the delirium assessment tool of Confusion Assessment Method for ICU (CAM-ICU). A questionnaire of sociodemographic and clinical characteristics of patients were used for collection of data. Patients’ folders were also used for the survey, in order to get more detailed information of their medical condition during the study period. Patients were assessed and monitored before surgery.
Delirium assessment started on the first postoperative day. The assessment was done in every shift, in order to record patients’ mental state changes. POD was evaluated using The Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) delirium assessment tool.
Delirium Screening
Diagnosis of delirium was made using Intensive Care Delirium Screening Checklist (ICDSC). The evaluation is based on 8 fields (1 point each): altered level of consciousness, inattention, disorientation, hallucination-delusion-psychosis, inappropriate speech or mood, psychomotor agitation/retardation, sleep-wake cycle disturbance, and fluctuating course of aforementioned items. An ICDSC score of 4 or greater indicates delirium. Delirium screening was started 12 hours after surgery and repeated every 8 hours during the patients’ ICU stay. This study was designated for investigating early onset of delirium following cardiac surgery; therefore screening period was limited to 5 days.
Delirium Assessment
Patient evaluations were performed using the Richmond Agitation - Sedation Scale (RASS) [51] (as shown in figure 1). POD was evaluated using The Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) [51] (as shown in Figure 2) delirium assessment tool, once daily for a maximum of 5 days or until CVICU discharge, whichever occurred first.
The assessments were all performed by the research team following rounds each day. That is, these data were not derived from routine bedside nurses’ CAM-ICU assessments, but rather they were obtained from RASS and CAM-ICU data conducted explicitly for this investigation by our trained research staff. Patients with a RASS score of −5 (unresponsive to physical and verbal stimulus) and −4 (responsive only to physical stimulus) are considered comatose, and thus ineligible for delirium evaluation; these patients were classified as “unable to assess.”
We used the RASS scale in concert with the CAM-ICU as a pragmatic approach to define motoric subtypes of delirium. Patients with positive RASS scores (+1 to +4) with every CAM-ICU positive evaluation were considered to have hyperactive delirium; delirium in these patients was manifested with positive symptoms of restlessness, agitation, combativeness and pulling of devices. Those with RASS scores of 0 to −3 with every CAM-ICU positive evaluation were considered as having hypoactive delirium manifesting negative symptoms such as lethargy, somnolence and inattention. Patients who during their ICU course were found to be delirious on at least one occasion manifesting positive symptoms (hyperactive or “loud” delirium) while on at least one other occasion manifesting negative symptoms (hypoactive, “quiet” or invisible delirium) were considered to have mixed delirium.
Assessment of Risk Factors
Variables expected to be associated with development of postoperative delirium were divided into 3 categories: preoperative, intraoperative, and postoperative. Information on risk factors was obtained from preoperative interview with the patient and using chart records. The intensity of pain was evaluated using Visual Analogue Scale (VAS).
Patients were assessed and monitored preoperatively, during surgery and in the early postoperative period, Patients were followed up for 5 consecutive days post-operatively, POD incidence and duration was documented using the confusion assessment method for the ICU checklist by 2 steps.
The statistical analysis was performed using IBM SPSS Statistics software (v. 23.0). (SPSS Inc., Chicago,IL, USA). The data are presented as the mean and the standard deviation (M(SD). Categorical data are presented as counts and percentages in brackets. One-sample Kolmogorov-Smirnov test was used for determination of quantitative data distribution. Normally, the Kolmogorov-Smirnov Z is computed from the largest difference (in absolute value) between the observed and theoretical cumulative distribution functions. This test tests whether the observations could reasonably have come from the specified distribution. Continuous scale data were compared using parametric ANOVA and non-parametric Kruskal-Wallis tests.
for comparison of discrete variables. Statistical tests were two‐sided, with p <0.05 considered significant.
FIGURE 1: Richmond Agitation and sedation scale
FIGURE 2: Confusion Assessment Method for ICU
•Ely EW. Confusion Assessment Method for the ICU (CAM-ICU). The Complete Training Manual. 2014. Available from: http://www.icudelirium.org/docs/CAM_ICU_training. •www.icudelirium.org •www.icudelirium.co.uk6. RESULTS
The incidence of POD after cardiac surgery with CPB was 28%. Average age of delirious patients was significantly higher than non-delirious patients 69.84(±10.01) vs 65.83(±10.61) yrs., p=0.003. The patients in I gr. had higher preoperative risk score: the body mass index was 28.8 (±4.4) (kg/min2), the majority were male (72.2%), ejection fraction was 46.1(±11.9)%. The analysis of perioperative period showed that average duration of CPB were longer 111.29(±41.05) vs 100.8(±36.87) min, p=0.003.
Table 1 shows the demographic and postoperative characteristics of patients who has undergone cardiac surgery on CPB according to postoperative delirium statues.
Table 1: Baseline Demographic, clinical, and perioperative patients’ characteristics
Variables Patient with Delirium (N=16) Patients without Delirium (N=74) P- Value Age(years) 69.84(±10.01) 65.83(±10.61) p=0.003 Male Gender (%) 72.2 27.8 Average duration of CPB 111.29(±41.05) min 100.8(±36.87) min p=0.003.
Duration in ICU Stay (days)
5.8(±2.89) vs 3.86(±1.91) p<0.001
Stay In Hospital After ICU (Days)
14.51(±11.67) 11.10(±9.07) p=0.016
Body mass index 28.8 (±4.4) (kg/min2)
Abbreviations: ICU- Intensive Care Unit, CPB- Cardio-pulmonary Bypass
Figure 3: Patients outcome
Preoperative risk factor analyses are presented in Table 2. In our final multivariable model, age, Left Ventricular ejection fraction and lent of stay in the hospital >6 days were associated with postoperative delirium. Increasing age > 70 was associated with higher risk of postoperative delirium.
Table 2: Pre-operative risk factors
Variables OR 95% Cl P value
Age >70 years 2.227 1.325-3.742 0.003 LVEF < 42% 2.398 1.325-3.742 0.002 Length of stay in the
hospital before surgery >6 days
1.840 1.064-3.180 0.029
Looking into patients’ perioperative risks factors in Table 3, we noticed the following findings: Patients who were on CPB for more than 86 minutes was associated with increased delirium risk. CPB > 86 min (OR: 2.068; 95% CI 1.182-3.618, p=0.009). Also we find that most patients who underwent combined surgical procedure had POD.
Table 3: Patients’ perioperative risks factors
Variable OR Cl P value Combined surgical Procedure 2.083 1.153-3.761 0.015 Duration of CPB>86min 2.068 1.182-3618 0.009
Abbreviations: OR- Odd Ratio, Cl- Confidential Interval, P value- Probability Value, CPB- Cardiopulmonary bypass.
From our finding, table 4 shows that postoperative arterial fibrillation associated with a 2.244(95% CI: 1.158, 4.347; p=0.007) absolute increased risk of postoperative delirium.
Table: 4 Postoperative risk factors
Variable OR Cl P value
Postoperative AF 2.244 1.158-4.347 0.007
Abbreviations: AF- arterial fibrillation, OR- Odd Ratio, Cl- Confidential Interval, P value- Probability Value.
longer period more than 10 day, and this was statistically significant (OR: 2.060; CI 1.226-3.460, p=0.006).
Prolong stay after ICU was found to be statistically significant; patients with delirium were hospitalized for a longer days 14.51(±11.67) than patients without delirium 11.10(±9.07). (p=0.016)
We also find prolong stay in the ICU statistically significant; patients who had delirium stayed in the ICU for longer days 5.8(±2.89) than patients without delirium 3.86(±1.91) (p<0.001).
Table 5: Clinical Outcome (1)
Variables OR Cl P value
Patients with POD required re-intubation more frequent
13.169, 1.456-119.087 p=0.022
POD prolonged the length of the postoperative hospital stay >10 days
2.060 1.226-3.460, p=0.006
Table: 6 Clinical Outcomes (2)
Variables Patients without Patients with
delirium
P value
POD prolonged the length of the ICU stay (days)
5.8(±2.89) 3.86(±1.91), p<0.001
POD prolonged the length of stay in the hospital after ICU (days)
14.51(±11.67) 11.10(±9.07) p=0.016
7. DISCUSSION OF THE RESULTS
Cardiac conditions have become prevalent among older populations worldwide. This has resulted in increased number of cardiac surgeries performed annually. Studies show, that most older populations that undergo cardiac surgery experience postoperative delirium (POD) which is now a major epidemiologic and clinical problem. Hence our study also showed incidence of delirium postoperatively.
During our one month study interval, 90 patients who have undergone elective cardiac surgeries on CBP were admitted to the ICU; Of the 90 patients enrolled in this study, 72.2% were men. Patients were divided into two groups, which are patients with postoperative delirium (I group) and non-delirious patients (II group). In all 16 patients had postoperative delirium and 74 patients were without delirium. Patients were screened for postoperative delirium by using the delirium assessment tool of Confusion Assessment Method for ICU (CAM-ICU).
Delirium is a neuropsychiatric syndrome indicated in changes in cognitive functions. According to the Diagnostic and Statistical Manual of Mental Disorders V, postoperative delirium is defined as an acute onset fluctuating change in mental status characterized by a reduced awareness of the environment and disturbance of attention. The key features of delirium according to the Diagnostic and Statistical Manual of Mental Disorders V are represented by disturbance in attention (that is reduced ability to direct, focus, sustain, and shift attention) and awareness.
Postoperative delirium after cardiac surgery has become a major health issues that affect older population. Studies have shown that the incidence in older surgical patients can go as far as 73% [50] Whiles this may be linked to sociodemographic factors, although previous studies have researched on postoperative delirium much attentions have not been given to how sociodemographic factors relates to postoperative delirium.
This study shows the influence of postoperative delirium on post-operative outcomes after cardiac surgery and its relation with sociodemographic factors and its aim at determining the incidence of postoperative delirium after cardiac surgery, to find its relation with sociodemographic factors and influence on post-operative outcomes.
Previous literatures have describe a numerous risk factors such as advanced age, dementia, hearing and visual impairment, diabetes mellitus, impaired left ventricular ejection fraction, electrolyte derangement, history of hypertension, alcoholism, smoking, severity of illness, pre-existing pulmonary disease, history of cerebrovascular disease, longer operation time, time on cardiopulmonary bypass (CPB), high perioperative transfusion requirement, postoperative hypertension, atrial fibrillation, postoperative tachycardia, high blood urea level, and pneumonia as independent predictors associated with POD.
Our study findings agreed with previous literature findings that time on CPB, atrial fibrillations, impaired left ventricular ejection fraction and advanced age are independent predictors of POD which are statistically significant. According to a recent literature review, atrial fibrillation was independently related with delirium after cardiac surgery. In our study demonstrated on table 5 that atrial fibrillation is a postoperative risks factor associated with POD.
The incidence of postoperative delirium has been reported in many literatures and it varies from 3.3% to 77%, depending on the patient population. From our study the incidence of POD on CPB was only 28%.
Literature classified advanced age >70 years as non-modifiable risk factors of postoperative delirium from our finding advanced age was find as preoperative risk factors that is associated to postoperative delirium In this study, we identified, longer duration of CPB, less ejection fraction and age >70 years as independent risk factors for the occurrence of POD. Hence age is also one of the risk factor for the postoperative delirium.
A literature also reveals that the risk of postoperative delirium after cardiac surgery is comparatively higher in patients who have valve replacement than in patients who have bypass surgery. In our study, Patients who were on CPB for more than 86 minutes were associated with increased delirium risk. CPB > 86 min (OR: 2.068; 95% CI 1.182-3.618, p=0.009).Hence CPB greater than 86 minutes is associated with high incidence of postoperative delirium.
gender was significantly sociodemographic factor associated with POD. Hence male should be more keenly observed postoperatively for the signs of delirium after cardiac surgeries.
Our study demonstrate that on table 6 and 7 shows that prolong stay in the ICU was
statistically significant; patients who had delirium stayed in the ICU for longer days 5.8(±2.89) than patients without delirium 3.86(±1.91) (p<0.001).There are many researches which showed that people who have delirium after cardiac surgery needs to stay more in the ICU. Nearly 25% of the people having delirium stays longer in the intensive care units. Hence delirium after cardiac surgery directly affects the length of the stay in the ICU.
Furthermore, from our study findings POD prolonged the length of the postoperative hospital stay more than 10 days as compared to patients without postoperative delirium and it agreement with a literature reviewed that stated that Postoperative delirium after cardiac surgery is related with in well as lengthened stay in both the intensive care unit and the hospital. Hence, the delirium after cardiac surgery directly affects the length of stay both in the intensive care units and the hospital wards.
Body mass index also have correlations with delirium in this study. Body mass index was 28.8 (±4.4) (kg/min2),
It was evidenced from our study that Patients with delirium required more frequent intubation was statically significant (OR: 13.169, CI 1.456-119.087, p=0.022).
POD may affect the many reasons and a multifactorial risk model such as elderly age, gender, longer duration of CPB and less ejection fraction should be applied to identify patients at increased risk of developing POD.
From our study, multivariate analysis remained as an independent predictors for POD: age > 70 yr (OR: 2.227; 95% CI 1.325-3.742, p=0.003), ejection fraction < 42% (OR: 2.398; 95% CI 1.397-4.117, p=0.002), duration of CPB > 86 min (OR: 2.068; 95% CI 1.182-3.618, p=0.009)
8. CONCLUSION
1. Study data suggest that POD is a common complication: applying Confusion Assessment Method for ICU, we determined that the incidence of POD after cardiac surgery was 28%.
2. POD worsen patient outcome following cardiac surgery: early postoperative delirium significantly prolonged the length in stay at the ICU and hospital stay after surgery and it associated with sociodemographic factors.
9. PRACTICAL RECOMMENDATION
Postoperative delirium is a common complication in elderly patients in cardiac surgical intensive care unit (ICU). Postoperative delirium after cardiac surgery is related with increased morbidity and
mortality as well as lengthened stay in both the intensive care unit and the hospital. There is certain specific factors have been identified to for the recommendation of postoperative delirium patients. This
recommendation focuses on health care professionals mainly nurses and physicians.
1.
Educate Health Care Professionals about postoperative Delirium
Healthcare systems and hospitals should organize seminars and educational programs for health care professional on identification of postoperative delirium as a postoperative complication to improve their understanding and knowledge on its causes, signs, epidemiology, assessment, prevention, and treatment. This will help in early identification of postoperative delirium and also prevent misdiagnosis.
2. Educate healthcare professional on how to use and evaluate delirium
using assessment tools.
Inadequate skill and knowledge on the use of delirium assessment tool will delay diagnosis which will or may further lead to poor prognosis or outcome of patients’ condition. Hence I recommend Hospitals to organize educational programs for their intensive care unit staffs on how to use assessment tool to evaluate delirium statues of patients postoperatively. To promote early detection, management and prevention
3. Nurse Role
Postoperative delirium is known to lead to high mortality rate, lengthy stay in the hospital, and cognitive disturbance in older adults. Because postoperative delirium negatively impacts the prognosis for hospitalized patients and complicates the provision of nursing care in any setting, prevention is very important. According to evidenced based, nurses have a greater chance in preventing postoperative delirium in older adults.
• Nurses should always educate patients and family about postoperative delirium that is the possibilities, causes, sign and symptoms, treatment and managements before surgery to allay patients and family off anxiety.
• Nurses should orient patients to the hospital and its annex and also introduce patients to the surgical team before surgery this will help patient get familiar to the hospital, its environment and the staffs in his departments.
• Nurses should recommend patients to visit psychologist for mental assessment before surgery especially those that have high risks of developing postoperative delirium example patients who are 65years and above. This will help nurses and other surgical team to know patients mental statues before surgery.
• Nurses should involve patients’ family in care. This will help promote patients recovery in case of postoperative delirium and also promote sense of wellbeing.
• Nurses should to provide same routines and continuity of care which will help the patient by getting familiar with the nurses which will help the nurses to easily identify any changes in patients.
• The nurse should use unit-wide noise-reduction strategies, provide light reduction, this will help improve patients sleep.
• Nurse should have proper communications and interpersonal relationship with patients. This helps patients to voice out his or her fears and also makes it easier for the nurse to identify any changes in patients.
4. Research
Nurses and health professionals are recommended to do more researches on postoperative delirium and its associate risk factors, signs and symptom, managements, treatments and preventions. This will help them to acquire more evidenced based skills and knowledge to take quality care of patients who undergo surgeries. Also authorities of hospitals should implement an award winning schemes in which awards will be given to health care professionals who write a research papers in order to promote quality of care. This will serve as a motivation for the staff and also promotes their knowledge and skills to provide quality of care to patients.
5. Pain management
cardiac surgery. It evidenced in a literature that proper pain management postoperatively reduce the occurrence of POD. Studies have shown that postoperative pain left unattended can lead to POD. The use of non-opioid pain medication to reduced postoperative pain has been highly recommended to prevent postoperative delirium in older adults. Furthermore, additional literature has reported the use of non-opioids such as paracetamol for postoperative pain can reduced the incidence of POD.
6. Avoid the use of inappropriate medications
Healthcare profession should avoid the used of medications that have been evidenced to be associated with causing POD such as anticholinergic drugs, meperidine and benzodiazepines. Rather used medications that have less chance in causing POD in patients. A recent literature published in the Journal of Clinical Anesthesia also provided meta-analytic evidence that dexmedetomidine could be the most viable and effective sedative agent or perioperative anesthetics to reduce postoperative delirium. This was also confirmed by a recent literature when they systematically reviewed trials focusing on prevention and treatment of delirium after cardiac surgery.
7. Comfortable environment
Environmental condition had played a vital role in both the genesis and management of delirium. Hence, it essential to provide good environment postoperatively.
Use of calm soothing music and fragrances at the patient side will be beneficial.
Patient’s room should have calendars as well as the big wall clocks. This will help them to remain oriented to time, place.
The patient bed side must have window from where he or she can witness the day light as well as night.
Clean environment should be maintained there with proper ventilation as well as noise free.
8. Postoperative observation
ulcers as well as risk of falls and fractures postoperatively. Patient’s safety should be priority in order to reduce any emergency situation.
10. LIST OF SCIENTIFIC REPORTS; PUBLICATION
In 2021, the abstract was selected for the oral presentation.
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12. ANNEXES
INDIVIDUAL PLAN OF PREPERATION OF THE GRADUTE MASTER’ S THESIS
Annex 3 by the Council of the Faculty of Nursing of LSMU
2018-09-13 protocol No SLF-9-5 LITHUANIAN UNIVERSITY OF HEALTH SCIENCES
MEDICAL ACADEMY FACULTY OF NURSING FELICIA MAMLE PARTEY
DECLARATION OF THE AUTHOR'S CONTRIBUTION AND ACADEMIC
HONESTY
The 04 th of 05 2021
Title of the graduate Master‘s thesis _The influence of postoperative delirium on post-operative outcomes after cardiac surgery and its relation with sociodemographic factors
(Title)
I have (please tick the right line with “x” and fill in as appropriate) (Full name of the post-graduate student, student ID No)
☐ independently formed and defined the topic of the graduate thesis, the scope of the research on the basis of personal observations: (please specify your previous research in this field, other sources and research that helped formulate the problem, objectives and tasks of the graduate thesis)
_______________________________________________________________ ☐ selected from those suggested by the tutor of the graduate thesis or other scientists,
lecturers: (please specify full name of the scientist or lecturer):
______________________________________________________________________ ______________________________________________________________________
I have been advised by researchers, lecturers and specialists during collection and assessment of material, and preparation of the graduate thesis, their contribution during preparation of the graduate thesis:
