European Journal of Cardiovascular Medicine

Major open abdominal surgeries are among the most physiologically demanding procedures, often accompanied by considerable surgical stress and a high incidence of postoperative complications. These complications may include wound infections, anastomotic leaks, sepsis, and delayed recovery, all of which contribute to extended hospital stays, increased healthcare costs, and heightened mortality risk (1,2). As such, the ability to accurately predict postoperative complications is critical to enhancing perioperative care and improving patient outcomes.

Serum albumin, a hepatic-synthesized plasma protein with a half-life of approximately 21 days, is traditionally regarded as a nutritional marker. It also plays a critical role in maintaining oncotic pressure, transporting various molecules, and modulating immune responses (3,4). More recently, its role as a marker of systemic inflammation has been increasingly recognized, particularly in critically ill and surgical patients (5,6). While the prognostic value of preoperative serum albumin levels in predicting surgical morbidity has been well-documented, the relevance of postoperative changes in albumin remains insufficiently studied, especially in the context of major open abdominal procedures (7).

Postoperative hypoalbuminemia can result from several factors, including inflammatory cytokine release, increased vascular permeability, fluid shifts, and dilutional effects due to intravenous resuscitation. This phenomenon, sometimes referred to as “dilutional hypoalbuminemia,” may serve as a reflection of the body's systemic response to surgical trauma (8). Several studies have reported associations between early postoperative declines in serum albumin and the development of complications in general surgical cohorts; however, data specific to open abdominal surgeries remain sparse (9,10).

Furthermore, while transient drops in albumin may be expected as part of the physiological response to surgery, sustained or significant reductions may indicate heightened inflammatory burden or impending complications such as sepsis or wound dehiscence. The precise timing, extent, and prognostic value of such albumin changes require further exploration. Additionally, integrating albumin kinetics with scoring systems such as the Modified Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (MPASS) could offer a more refined approach to risk stratification (11).

This study was thus designed to assess the correlation between postoperative serum albumin levels and postoperative complications in patients undergoing elective major open abdominal surgeries. It aims to determine whether a postoperative drop in albumin, particularly ≥1 g/dL within the first 24 hours, can serve as an early, accessible, and cost-effective predictor of adverse outcomes, thereby guiding timely clinical interventions.

Study Design and Duration
This was a prospective, randomized observational study conducted over a period of two years, from February 2023 to January 2025.

Study Setting
The study was carried out in the Department of General Surgery at Kalinga Institute of Medical Sciences (KIMS), Bhubaneswar.

Study Population
Patients scheduled for elective major open abdominal surgeries were enrolled after fulfilling the inclusion criteria.

Inclusion Criteria

• Patients aged >18 years
• Undergoing elective major open abdominal surgeries with a duration exceeding 2 hours

Exclusion Criteria

• Age <18 years
• Emergency surgical procedures
• Preoperative sepsis or gastrointestinal perforation
• Patients on immunosuppressants or preoperative antibiotic therapy

Sample Size Calculation
Based on the findings of Labgaa et al. (2017), taking the correlation coefficient (r = 0.383) between postoperative albumin change (ΔAlb) and the Comprehensive Complication Index (CCI), with 95% confidence level and 95% statistical power, the required sample size was calculated as 84 patients.

Ethical Approval and Consent
Ethical clearance was obtained from the Institutional Ethics Committee prior to commencement of the study. Written informed consent was secured from all participants after explanation of the study objectives and procedures.

Data Collection and Variables

• Demographic data: Age, gender, BMI, comorbidities (hypertension, diabetes, COPD, CKD, etc.)
• Surgical details: Type and duration of surgery, intraoperative blood loss
• Biochemical investigations:
• Serum albumin measured preoperatively, at 6 hours post-surgery, on Postoperative Day 1 (POD1), and Day 3
• A decrease in serum albumin ≥1 g/dL by POD1 was considered significant
• Outcome assessment: Postoperative complications including surgical site infection (SSI), sepsis, and anastomotic leak were recorded during inpatient stay and follow-up.

Scoring System
The Modified Physiological and Operative Severity Score for the enumeration of Mortality and Morbidity (MPASS) was used to assess surgical stress.

Statistical Analysis
Data were entered in Microsoft Excel and analyzed using SPSS software (version X.X).

• Continuous variables were expressed as mean ± standard deviation (SD) and analyzed using the unpaired t-test.
• Categorical variables were analyzed using Chi-square test.
• Diagnostic parameters including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy (DA) were calculated.
• ANOVA was used where applicable for comparisons across more than two groups.
• A p-value <0.05 was considered statistically significant.

A total of 84 patients who underwent major open abdominal surgeries were included in this study. The mean age of the study population was 61.50 ± 14.36 years, with a male predominance (66.7% male, 33.3% female). The majority of patients had a body mass index (BMI) > 25 (n=48, 57.1%) and existing comorbidities such as diabetes or hypertension (n=52, 61.9%).

Incidence of Postoperative Complications
Out of 84 patients, 45 (53.6%) developed one or more postoperative complications, including surgical site infection (n=18), sepsis (n=12), pneumonia (n=7), and anastomotic leakage (n=8) (Table 1).

Postoperative Albumin Trends
The mean preoperative serum albumin level was 3.94 ± 0.31 g/dL, which declined significantly to 2.81 ± 0.42 g/dL on Postoperative Day 1 (POD1) (p<0.001) and further to 2.63 ± 0.50 g/dL by POD3. A drop of ≥1 g/dL in serum albumin was observed in 32 (71.1%) patients with complications and in 1 (2.6%) of those without complications, showing a statistically significant association (p<0.001) (Table 2).

Correlation with Clinical Variables

• Age >60 years, male gender, BMI >25, presence of comorbidities, surgery duration >3 hours, and intraoperative blood loss >200 mL were all significantly associated with higher complication rates (p<0.05 for all) (Table 3).
• A significant albumin drop was more frequent in patients with longer operative times and higher blood loss (Table 4).

Diagnostic Performance of Albumin Drop ≥1 g/dL
This threshold demonstrated:

• Sensitivity: 71.1%
• Specificity: 97.4%
• Positive Predictive Value (PPV): 97%
• Negative Predictive Value (NPV): 74.5%
• Diagnostic Accuracy: 83.3% (Table 5)

Correlation with MPASS
Higher MPASS scores were significantly associated with greater reductions in serum albumin and increased risk of complications (p<0.001), suggesting strong correlation between surgical stress and biochemical changes (Table 6).

Table 1: Frequency and Types of Postoperative Complications (n=84)

Table 2: Association Between Albumin Drop (≥1 g/dL) and Postoperative Complications

Chi-square test, p < 0.001

Table 3: Association of Clinical Variables with Postoperative Complications

Table 4: Operative Factors and Serum Albumin Drop

Table 5: Diagnostic Performance of Albumin Drop ≥1 g/dL for Predicting Complications

Table 6: Correlation Between MPASS Score and Albumin Levels

ANOVA test, p < 0.001

This study highlights the clinical significance of early postoperative serum albumin decline as a predictor of complications following major open abdominal surgeries. The findings demonstrate that a drop of ≥1 g/dL in serum albumin within 24 hours postoperatively is strongly associated with an increased risk of adverse outcomes, particularly wound infections, sepsis, pneumonia, and anastomotic leaks.

Serum albumin, though traditionally regarded as a nutritional marker, is now increasingly recognized as a sensitive marker of systemic inflammation and surgical stress response (1,2). A rapid postoperative decrease in albumin is often attributed to acute-phase responses, hemodilution, increased capillary permeability, and protein redistribution rather than malnutrition alone (3,4). The significant albumin drop observed in the majority of patients with complications in this study supports this hypothesis.

The predictive value of serum albumin is well established in various surgical and critical care contexts. Labgaa et al. reported that a decline in albumin within 24 hours post-surgery was a strong independent predictor of complications in abdominal surgery patients (5). Similarly, Gibbs et al. found preoperative hypoalbuminemia to be an independent predictor of postoperative morbidity and mortality (6). However, postoperative changes, particularly early drops in serum albumin, may offer better predictive value since they reflect acute responses to intraoperative insults and early pathophysiologic changes (7,8).

In this study, the diagnostic performance of a ≥1 g/dL albumin drop showed high specificity (97.4%) and positive predictive value (97%), aligning with prior findings that emphasize its usefulness as a screening tool for early risk stratification (9). The high specificity suggests that patients without this decline are less likely to develop complications, thereby aiding in postoperative surveillance and potentially reducing unnecessary interventions (10).

The correlation between albumin drop and prolonged operative time and increased blood loss also indicates that intraoperative physiological stress plays a critical role in postoperative outcomes (11). This reinforces the concept that albumin kinetics could serve as a surrogate marker for surgical trauma intensity and systemic inflammatory burden (12). Additionally, the significant correlation between higher MPASS scores and greater albumin drops in our study further validates the use of albumin as a dynamic marker for surgical severity (13).

Age, BMI, gender, and comorbidities also significantly influenced the risk of complications, consistent with existing literature (14,15). However, serum albumin decline provided a quantifiable and objective marker that surpassed the predictive capabilities of demographic parameters alone.

While our findings are promising, this study is limited by its single-center design and relatively small sample size. Future multicentric studies with larger populations could further validate the utility of serum albumin drop as an early prognostic indicator. Moreover, integrating serum albumin monitoring with other inflammatory biomarkers like C-reactive protein or procalcitonin may enhance predictive accuracy.

In conclusion, this study supports the early postoperative serum albumin decline as a reliable, cost-effective, and non-invasive biomarker for predicting complications following major abdominal surgeries. Routine monitoring of albumin may facilitate timely clinical decision-making and improve patient outcomes.

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