Fatigue is among the most prevalent symptoms in postoperative patients, severely impacting patients’ postoperative rehabilitation and quality of life. Early prediction of POF as well as taking intervention measures is critical. Our finding showed five modifiable factors (intraoperative anxiety, average dosage of propofol by weight, change rates of HR, fatigue 30 min after endoscopy, and intraoperative hypotension) and nine non-modifiable factors (age, gender, drinker, numbers of comorbidities, degree of education, married, Buddhist, endoscopic treatment, and intraoperative tracheal intubation) were independently associated with severity of fatigue 24h after digestive endoscopy with anesthesia assistance. Taking these factors into account, we constructed and validated a nomogram to enable early prediction of 24h-POF in patients undergoing digestive endoscopy, allowing clinical staff to implement effective strategies for prevention, nursing and intervention before patients leave the hospital.
Fatigue, a multifaceted subjective sensation, which is manifested as a depletion of energy, stamina, and vitality in everyday life. POF in endoscopic patients is different to general fatigue, as it is directly induced by surgery and volatile[32]. In endoscopy patients, POF is described as “an unbelievable and unrecoverable loss of vitality that is beyond one’s own control”, and is reported as one of the most challenging symptom to manage[11]. This study found that 24h-POF in patients underwent endoscopic operation with anesthesia assistance was 40.43%, which is close to previous finding[13].
This nomogram comprises 14 variables, which have been demonstrated as independent predictors of 24-hour POF in patients undergoing endoscopy through univariate and multiple linear regression analyses, and these variables can be readily obtained in clinical practice. In terms of modifiable factors, the APAIS score was demonstrated to be a strong predictor of POF in this study. A similar study reported that preoperative negative emotions, including anxiety, depression, and anger, were positively associated with the severity of POF in inpatients after surgery[33-35]. Previous studies have indicated preoperative anxiety can increase the release of proinflammatory factors and stimulate hypothalamus-pituitary-adrenalin (HPA) axis by enhancing the endocrine and immune responses induced by surgery, while dysfunction of HPA axis often exacerbates patients' POF through various signaling pathways[36, 37]. This may offer an explanation for our findings. Next, hypotension deduces blood supply and diminishes oxygen content to the brain, thereby exacerbating postoperative dizziness symptoms[38]. Then, high change rates of HR, drinker, and large dosage of propofol were related to higher POF level. A greater heart rate variability signifies a heightened stress response, leading to enhanced catabolism within the body [39]. From the perspective of central fatigue mechanism, increased catabolism results in elevated tryptophan levels both the peripheral circulation system and brain[40]. As a precursor of 5-hydroxytryptamine(5-HT), tryptophan converts into more 5-HT, causing central fatigue. Furthermore, the rise in tryptophan levels can stimulate the N-Methyl-D-aspartic acid (NMDA) receptor to produce neurotoxicity, leading to nerve cell destruction and dysfunction [41]. Prior studies have indicated that sedation is less effective in heavy drinkers due to abnormal enhancement of the microsomal ethanol oxidizing system (MEOS), accelerating the degradation of drugs [42, 43]. Therefore, drinkers often require a larger dose of propofol to achieve sedation[44]. A high dosage of propofol not only induces cardiovascular depression but also over-sedation, inevitably leading to POF [45]. Does this imply that a lower average dosage of propofol is better? Clearly not. Researchers have revealed that single administration of propofol at 0.1mg/kg, could promote POF improvement by enhancing gluconeogenesis though CREB/PGC-1a signaling and accelerating FFA β-oxidation in 70% hepatectomy rats, to be emphasized, the dosage of propofol used here was at least 1000 times lower than that of conventional anesthetics[46]. It is suggested that future research should explore threshold for propofol-induced POF and develop a program foe rational use of propofol, ensuring the patients’ sedation level and maintain the stability of BP and HR during digestive endoscopy. Finally, it was found that 30 min fatigue after endoscopy was an independent predictor of 24h-POF. Studies have reported that aromatherapy, which is easy to implement in clinical settings, can effectively reduce POF of patients[47].
The older was linked to higher 24h-POF, POF score assessed by ChrFS increases by 0.196 for each year of age in this study, we suppose the normal physiological activities of endocrine-metabolic system in the elderly recover slowly because of the decline of physical function[9]. But this result was contrary from a Chinese study, the discrepancy may be due to the different sample sizes [15, 48]. Buddhism has lower POF level than non-believers, positive religious coping styles in Buddhists’ life signified an internalized secure spiritual relationship and well-integrated copying resources on which they could rely across a variety of stress situations [49]. Previous study have shown Buddhist beliefs could treat bone pain caused by cancer in a study conducted in Hong Kong, we infer that the Buddhists may also turn to their faith for coping using private prayer, meditation, or Chanting when facing uncontrollable fatigue related to endoscopy [50].
The performance of nomogram to predict 24h-POF in patients undergoing endoscopy was evaluated from discrimination, accuracy and clinal utility. The AUC of both training and validation cohorts were greater than 0.8, the AUC of 1000 bootstrapped samples in training cohorts was greater than 0.8 as well, it showed the predicted model has excellent discrimination in ascertain 24h-POF in endoscopic patients. Additionally, the calibration plot and H-L test (P > 0.05) demonstrated high degree of fit between the actual accuracy and predicted accuracy which indicating the predicted accuracy of the model predictions. DCA plot demonstrated the model’s high clinical utility. Hence, the nomogram could assist medical staff in conducting dynamic assessments, identifying groups with high level of POF, and implementing early measures and interventions, thus improving patients’ quality of postoperative rehabilitation and quality of life.
Although our study conducted a model to predict and validate the 24h-POF in patients undergoing endoscopic treatment under anesthesia, several limitations still need to be considered. Firstly, our research carried out for seven months rather than a whole year, the fatigue feelings may be differed from diverse season or periods. Secondly, Christensen Fatigue Scale is a single-dimensional numeric rating scale that can’t distinguish potential different aspects of POF. Thirdly, our study lacks external validation, so we plan to conduct larger prospective studies to validate and optimize our predicted model.