Preoperative anxiety is common among patients undergoing surgery and may influence perioperative physiological responses, anesthetic requirements, and postoperative recovery. Recent evidence suggests that greater preoperative anxiety may be associated with increased anesthetic requirements, although its relationship with postoperative pain remains less consistent [1]. Several clinical studies have demonstrated an association between preoperative anxiety and anesthetic consumption. Higher anxiety levels have been associated with increased propofol requirements during general anesthesia, while anxiety and pain sensitivity may independently influence anesthetic requirements and postoperative recovery [2,3]. Earlier work also demonstrated that preoperative anxiety can affect intraoperative anesthetic requirements, supporting its importance as a patient-related factor during anesthetic management [4]. Preoperative anxiety may additionally influence postoperative pain perception and analgesic requirements. Prospective evidence has reported an association between greater preoperative anxiety and increased postoperative pain following elective surgery [5]. However, the available evidence is not entirely consistent, and recent systematic evidence suggests that the relationship between anxiety and acute postoperative pain may be weaker than its relationship with anesthetic requirements [1]. Accurate assessment of anxiety is therefore important when evaluating its perioperative effects. Standardized instruments, including the Amsterdam Preoperative Anxiety and Information Scale and the State-Trait Anxiety Inventory (STAI), have been used to quantify anxiety in surgical patients [6]. Preoperative anxiety has also been associated with hemodynamic changes during induction of anesthesia, suggesting that anxiety may have measurable physiological consequences in the peri-induction period [7]. The STAI has been used in different preoperative settings to assess state anxiety and facilitate standardized evaluation of patients undergoing surgical procedures [8,9]. Despite increasing evidence regarding the influence of preoperative anxiety on anesthetic management, the relationship between anxiety level, intraoperative anesthetic requirement, and postoperative pain remains incompletely established. Therefore, the present study was undertaken to assess the effect of preoperative anxiety on intraoperative anesthetic requirements and postoperative pain scores in patients undergoing elective surgery under general anesthesia.

Study Design and Setting This prospective observational study was conducted in the Department of Anaesthesiology at a tertiary-care hospital to assess the association between preoperative anxiety, intraoperative anesthetic requirements, and postoperative pain. Institutional Ethics Committee approval was obtained, and written informed consent was taken from all participants. Participants A total of 100 adult patients aged 18–65 years, classified as American Society of Anesthesiologists (ASA) physical status I or II and scheduled for elective surgery under general anesthesia, were included. Patients with diagnosed psychiatric illness, regular anxiolytic or antidepressant use, chronic pain or opioid use, cognitive impairment preventing questionnaire completion, significant systemic disease, emergency surgery, or inability to provide informed consent were excluded. Assessment of Preoperative Anxiety Preoperative anxiety was assessed before induction using the State-Trait Anxiety Inventory-State (STAI-S). Higher scores indicated greater preoperative anxiety. The STAI-S score was primarily analyzed as a continuous variable. Anesthetic Management Standard monitoring, including electrocardiography, noninvasive blood pressure, and pulse oximetry, was performed. General anesthesia was induced using intravenous propofol, with the dose titrated according to clinical response. The total propofol requirement was recorded as the primary measure of intraoperative anesthetic requirement. Intraoperative opioid consumption and peri-induction hemodynamic parameters were also documented. Postoperative Pain Assessment Postoperative pain was assessed using an 11-point Numerical Rating Scale (NRS; 0 = no pain, 10 = worst imaginable pain) at 1, 2, 6, 12, and 24 hours after surgery. The requirement and total dose of rescue analgesia during the first 24 hours were recorded. Outcome Measures The primary outcomes were the associations between the preoperative STAI-S score and the intraoperative propofol requirement and the postoperative pain scores. Secondary outcomes included intraoperative opioid consumption, rescue analgesic requirement, peri-induction hemodynamic changes, and postoperative adverse events. Statistical Analysis Continuous variables were expressed as mean ± standard deviation or median with interquartile range, as appropriate, and categorical variables as frequencies and percentages. Pearson or Spearman correlation was used to assess associations between anxiety scores and perioperative outcomes. Multivariable linear regression was performed to determine whether preoperative anxiety independently predicted anesthetic requirement and postoperative pain after adjustment for relevant demographic and clinical variables. A p-value <0.05 was considered statistically significant.

A total of 100 patients undergoing elective surgery under general anesthesia were included in the study. The demographic and clinical characteristics of the study population are presented in Table 1. The mean age of the participants was 42.3 ± 11.6 years, and the majority were ASA physical status I. Baseline characteristics were comparable across the predefined anxiety categories. Table 1. Baseline Characteristics of Study Participants Variable Overall (N=100) Age (years), mean ± SD 42.3 ± 11.6 Male, n (%) 56 (56.0) Female, n (%) 44 (44.0) Weight (kg), mean ± SD 64.8 ± 9.2 ASA I, n (%) 61 (61.0) ASA II, n (%) 39 (39.0) Duration of surgery (min), mean ± SD 86.4 ± 24.7 Values are expressed as mean ± SD or frequency (percentage). ASA: American Society of Anesthesiologists. Preoperative anxiety was assessed using the STAI-State scale. The mean preoperative STAI-S score was 44.8 ± 9.6. Patients were categorized according to their anxiety level for descriptive analysis. Patients with higher anxiety scores demonstrated greater propofol requirements during induction (Table 2). Table 2. Preoperative Anxiety and Anesthetic Requirement Anxiety category n STAI-S score, mean ± SD Propofol requirement (mg), mean ± SD p-value Low anxiety 31 34.6 ± 3.8 137.2 ± 17.5 Moderate anxiety 43 44.1 ± 3.6 151.8 ± 19.2 High anxiety 26 57.2 ± 5.1 168.5 ± 21.4 <0.001* STAI-S: State-Trait Anxiety Inventory-State. p < 0.05 was considered statistically significant. A significant positive correlation was observed between preoperative STAI-S score and total propofol requirement (r = 0.52, p < 0.001). Intraoperative opioid consumption also demonstrated a positive association with preoperative anxiety score. After adjustment for age, sex, ASA status, weight, and duration of surgery, preoperative anxiety remained independently associated with higher propofol requirement (Table 3). Table 3. Association Between Preoperative Anxiety and Intraoperative Anesthetic Requirement Outcome Correlation with STAI-S p-value Adjusted β (95% CI) Adjusted p-value Total propofol requirement 0.52 <0.001* 0.48 (0.31–0.65) <0.001* Intraoperative opioid consumption 0.31 0.002* 0.27 (0.09–0.45) 0.004* STAI-S: State-Trait Anxiety Inventory-State; CI: confidence interval. Multivariable analysis was adjusted for age, sex, weight, ASA status, and duration of surgery. p < 0.05 was considered statistically significant. Postoperative pain scores were higher among patients with greater preoperative anxiety, particularly during the early postoperative period. The mean NRS pain score at 1 hour was 4.2 ± 1.5, increasing with increasing anxiety category. Patients with higher anxiety also required greater amounts of rescue analgesia during the first 24 postoperative hours (Table 4). Table 4. Preoperative Anxiety and Postoperative Pain Outcomes Outcome Low anxiety (n=31) Moderate anxiety (n=43) High anxiety (n=26) p-value NRS at 1 hour 3.3 ± 1.2 4.2 ± 1.3 5.1 ± 1.4 <0.001* NRS at 2 hours 3.0 ± 1.2 3.8 ± 1.3 4.7 ± 1.5 <0.001* NRS at 6 hours 2.6 ± 1.1 3.3 ± 1.2 4.0 ± 1.4 0.001* NRS at 12 hours 2.3 ± 1.0 2.9 ± 1.1 3.5 ± 1.3 0.002* NRS at 24 hours 2.0 ± 0.9 2.5 ± 1.0 3.1 ± 1.2 0.001* Time to first rescue analgesia (min) 374.2 ± 82.5 329.6 ± 76.8 285.7 ± 71.4 <0.001* 24-hour rescue analgesic consumption (mg) 72.4 ± 24.6 89.7 ± 27.8 108.6 ± 31.5 <0.001* NRS: Numerical Rating Scale. p < 0.05 was considered statistically significant. Overall, higher preoperative anxiety was associated with greater intraoperative propofol requirements and higher postoperative pain scores. The association remained significant after adjustment for relevant demographic and clinical factors, suggesting that preoperative anxiety may be an independent predictor of perioperative anesthetic and analgesic requirements.

The present study assessed the association between preoperative anxiety, intraoperative anesthetic requirements, and postoperative pain in patients undergoing elective surgery under general anesthesia. Patients with higher preoperative anxiety scores required greater amounts of propofol and experienced higher postoperative pain scores. Preoperative anxiety remained independently associated with propofol requirement after adjustment for relevant clinical variables. The observed association between preoperative anxiety and anesthetic requirement is consistent with previous studies. Inal et al. reported that preoperative anxiety was associated with increased propofol consumption and also influenced postoperative recovery and pain. [2] Similarly, Kil et al. identified preoperative anxiety and pain sensitivity as independent predictors of propofol and sevoflurane requirements during general anesthesia. [3] These findings suggest that psychological factors may contribute to the substantial interindividual variability in anesthetic requirements observed during clinical practice. Our findings are also consistent with the earlier study by Maranets and Kain, which demonstrated that preoperative anxiety influenced intraoperative anesthetic requirements. [4] Increased anxiety may potentially alter arousal and sympathetic activity and consequently influence the amount of anesthetic required to achieve an adequate depth of anesthesia. However, the present study did not directly evaluate sympathetic activity or anesthetic depth using objective monitoring; therefore, these mechanisms remain possible explanations rather than established causal pathways. A higher level of preoperative anxiety was also associated with greater postoperative pain in the present study. Patients with higher anxiety scores demonstrated higher NRS pain scores during the postoperative period and required greater amounts of rescue analgesia. This finding is supported by the prospective study of Tadesse et al., which reported an association between preoperative anxiety and postoperative pain following elective surgery. [5] Psychological distress may influence pain perception and postoperative coping, potentially contributing to increased analgesic requirements. Nevertheless, the relationship between preoperative anxiety and postoperative pain is not entirely consistent across the literature. The recent systematic review and meta-analysis by Shebl et al. found stronger evidence for an association between preoperative anxiety and anesthetic requirements, whereas the evidence for an association with acute postoperative pain was less conclusive. [1] Furthermore, Bakker-Bons et al. reported an association between preoperative anxiety and chronic postsurgical pain but emphasized considerable heterogeneity among the available studies. [10] Therefore, the higher postoperative pain observed in our study should be interpreted as an association rather than evidence that anxiety directly causes increased postoperative pain. The use of a standardized anxiety assessment is important when investigating these relationships. The State-Trait Anxiety Inventory has been used extensively to quantify preoperative anxiety, allowing anxiety to be assessed systematically rather than relying on subjective clinical judgment. [8,9] The Amsterdam Preoperative Anxiety and Information Scale is another validated instrument used in surgical populations and provides an alternative approach to assessing preoperative anxiety. [6] Differences in the instruments used across studies may contribute to variation in reported associations. Preoperative anxiety may also have measurable physiological consequences during induction of anesthesia. Kim et al. demonstrated an association between preoperative anxiety and hemodynamic changes during induction, suggesting that anxiety may influence the peri-induction physiological response. [7] This is relevant because increased sympathetic activation associated with anxiety could potentially contribute to altered cardiovascular responses and anesthetic requirements. However, anxiety-related physiological changes were not the primary focus of the present study, and the observed associations should not be interpreted as evidence of a specific physiological mechanism. The clinical implications of these findings are relevant to perioperative anesthetic planning. Identification of patients with substantial preoperative anxiety may allow the anesthesiologist to anticipate potentially greater anesthetic requirements and increased postoperative analgesic needs. However, anxiety should be considered alongside other factors, including age, sex, type and duration of surgery, baseline pain sensitivity, and anesthetic technique. It should not be assumed that all patients with higher anxiety will necessarily require greater doses of anesthetic or analgesic medication. The present study has several limitations. First, its observational design permits identification of associations but does not establish causality. Second, the sample size was relatively small and the study was conducted at a single center, which may limit generalizability. Third, anxiety was assessed at a single preoperative time point and may have changed during the perioperative period. Postoperative pain is also multifactorial and may be influenced by surgical characteristics, individual pain sensitivity, and postoperative analgesic management. Finally, the study did not incorporate objective measures of anesthetic depth or physiological markers of anxiety. Despite these limitations, the study provides clinically relevant evidence that preoperative anxiety is associated with both anesthetic requirements and postoperative pain. The findings are consistent with previous evidence linking anxiety with propofol consumption and anesthetic requirements [1-4] and with prospective and systematic evidence examining its relationship with postoperative pain [5,10]. Future multicenter studies with larger samples, repeated anxiety assessments, standardized anesthetic protocols, and objective measures of anesthetic depth and pain processing may further clarify the magnitude and mechanisms of these associations.

Higher preoperative anxiety was associated with greater intraoperative propofol requirements and higher postoperative pain scores in patients undergoing elective surgery under general anesthesia. These findings suggest that preoperative anxiety may be an important patient-related factor influencing perioperative anesthetic and analgesic requirements. Routine assessment of anxiety before surgery may help identify patients who could require closer perioperative monitoring and individualized anesthetic and analgesic management. However, given the observational design and relatively small sample size, these findings should be interpreted as associations, and larger prospective studies are required to establish their clinical significance.

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