Retrospective review of anesthesia techniques and postoperative complications in patients with uremia undergoing colorectal cancer surgery

Abstract

BACKGROUND

Patients with uremia undergoing colorectal cancer surgery face an increased risk of postoperative complications due to impaired renal function, challenges in fluid balance, and the complexities of anesthetic management. Effective anesthesia and fluid strategies are critical to reducing complications and improving outcomes. Total intravenous anesthesia (TIVA) and goal-directed fluid therapy (GDT) have been suggested to enhance perioperative stability compared with inhalational anesthesia and standard fluid therapy. However, evidence supporting their efficacy in patients with uremia remains limited.

AIM

To evaluate the effects of different anesthetic techniques on postoperative complications in patients with uremia undergoing colorectal cancer surgery.

METHODS

This retrospective cohort study included 120 patients with stage 3-5 uremia who underwent elective colorectal cancer surgery between January 2022 and December 2024. Patients received either inhalational anesthesia or TIVA, combined with either standard fluid therapy or GDT. The primary outcome measure was the incidence of postoperative complications. Secondary outcomes included length of hospital stay, major complications, and 30-day mortality.

RESULTS

Postoperative complications occurred in 23.3% (28/120) of patients. TIVA was associated with a lower complication rate than that of inhalational anesthesia (20.0% vs 26.7%, P = 0.045). GDT resulted in significantly reduced fluid administration (2400 mL vs 3100 mL, P < 0.001) and lower complication rates (19.5% vs 28.2%, P = 0.030) compared with those of standard management. Independent risk factors for complications included age over 75 years (OR: 2.40, 95%CI: 1.60-3.60), stage 5 uremia (OR: 1.85, 95%CI: 1.20-2.85), and cumulative fluid balance exceeding 2000 mL (OR: 1.70, 95%CI: 1.10-2.65). Patients with complications had longer hospital stays (median, 15 days vs 11 days; P < 0.001) and higher rates of major complications (27.8% vs 13.5%; P = 0.003).

CONCLUSION

In patients with uremia undergoing colorectal cancer surgery, TIVA and GDT are associated with a lower incidence of postoperative complications compared with that of inhalational anesthesia and standard fluid management. Optimizing anesthetic techniques and fluid management may improve postoperative outcomes in this high-risk population.

Key Words: Patients with uremia; Postoperative complications; Total intravenous anesthesia; Goal-directed fluid therapy; Colorectal cancer surgery

Core Tip: This study evaluated the effects of anesthetic techniques and fluid management on postoperative complications in patients with uremia undergoing colorectal cancer surgery. These findings suggest that total intravenous anesthesia and goal-directed fluid therapy significantly reduce complication rates compared with those of inhalational anesthesia and standard fluid therapy. Advanced age, severe uremia, and excessive fluid balance were identified as key risk factors for complications. Optimizing anesthesia and fluid strategies may improve postoperative outcomes and reduce hospital stays in this high-risk population.

INTRODUCTION

Patients with uremia undergoing major colorectal cancer surgery constitute a particularly vulnerable population and present unique perioperative challenges[1]. These patients are at an increased risk of adverse outcomes, including higher mortality rates, prolonged hospital stays, and elevated postoperative complication rates, compared to individuals with normal renal function[2,3]. Notably, the risk of postoperative complications can affect up to 50% of patients with uremia following major abdominal surgeries, leading to poor outcomes[4].

The complex pathophysiology of uremia poses significant challenges to intraoperative management, particularly regarding the selection of anesthetic agents and fluid administration[5]. Altered drug metabolism and fluid homeostasis in patients with uremia can influence the pharmacokinetics and pharmacodynamics of anesthetics, potentially increasing the risk of postoperative cognitive dysfunction and other complications[6]. The choice of anesthetic agents and fluid management strategies may significantly impact the incidence of postoperative complications in this population[7,8].

Traditional intraoperative fluid management in patients with uremia has largely followed empirical guidelines. However, emerging evidence indicates that individualized goal-directed fluid therapy (GDT) may improve outcomes[9]. Additionally, the selection of anesthetic agents requires careful consideration of their metabolic pathways and potential interactions with compromised renal function[10]. Certain anesthetic protocols may offer better protection against postoperative cognitive complications[11,12].

The interplay among uremia, major colorectal cancer surgery, and postoperative complications is a critical area warranting further investigation, as current evidence remains limited and sometimes contradictory[13]. However, the relation between intraoperative management strategies and postoperative outcomes in this specific patient population has not been fully elucidated[14]. Therefore, this study aimed to assess the effect of different anesthesia and fluid management strategies on surgical outcomes, particularly postoperative complications, in patients with uremia undergoing colorectal cancer surgery.

MATERIALS AND METHODS

Study design and population

This retrospective cohort study was conducted at Lanxi Traditional Chinese Medicine Hospital from January 2022 to December 2024. The study protocol was approved by the Institutional Review Board (IRB number: IEC-2023-157). Written informed consent was obtained from all patients, and all procedures adhered to the Declaration of Helsinki and relevant institutional guidelines.

Grouping criteria: Patients were allocated to the inhalation or total intravenous anesthesia (TIVA) group based on the primary anesthetic technique selected at induction and to the GDT or standard fluid group depending on whether advanced hemodynamic monitoring was employed, in accordance with institutional protocols published in 2022.

Patient selection

The medical records of adult patients (≥ 18 years) with uremia (stages 3-5) who underwent elective colorectal cancer surgery under general anesthesia were reviewed. Uremia was defined according to the Kidney Disease: Improving Global Outcomes criteria based on the estimated glomerular filtration rate (eGFR) calculated using the CKD-EPI equation. The eGFR was determined using the most recent serum creatinine value obtained within 30 days prior to surgery. Uremia staging was defined as follows: Stage 3: eGFR 30-59 mL/min/1.73 m²; stage 4: eGFR 15-29 mL/min/1.73 m²; stage 5: eGFR < 15 mL/min/1.73 m².

Exclusion criteria included acute kidney injury at the time of surgery (defined as an increase in serum creatinine by ≥ 0.3 mg/dL within 48 hours or ≥ 1.5 times baseline within 7 days), emergency surgery, missing perioperative data, preexisting cognitive impairment or neurological disorders affecting complication assessment, severe hepatic dysfunction (Child-Pugh class C), uncontrolled diabetes mellitus (HbA1c > 9%), and New York Heart Association class IV heart failure, to minimize confounding factors.

Preoperative assessment and preparation

Stroke volume variation (SVV) was maintained below 13%, cardiac index between 2.5 and 4.0 L/min/m², and mean arterial pressure between 65 and 90 mmHg.

All patients underwent comprehensive preoperative evaluations, including detailed medical histories, physical examinations, laboratory tests, and relevant imaging studies. Standard preoperative laboratory tests included a complete blood count, comprehensive metabolic panel, coagulation profile, and arterial blood gas analysis. Cardiac evaluation included electrocardiography and echocardiography when clinically indicated. Patients were instructed to continue routine medications, except for angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, which were discontinued 24 hours before surgery.

Anesthesia management

Standardized preoperative fasting guidelines were followed (6 hours for solids and 2 hours for clear liquids). Upon arrival in the operating room, standard ASA monitoring was initiated, including electrocardiography, noninvasive blood pressure measurement, pulse oximetry, and capnography. Arterial catheterization was performed for continuous blood pressure monitoring and blood sampling. Central venous catheterization was performed based on surgical complexity and patient condition.

General anesthesia was induced with propofol (1.5-2.5 mg/kg), fentanyl (1-2 μg/kg), and rocuronium (0.6-0.9 mg/kg), with dosages adjusted according to individual patient characteristics and uremia stage. In patients with stage 5 uremia, the doses of propofol and fentanyl were reduced by 25%. Endotracheal intubation was performed using video laryngoscopy to minimize airway trauma.

Anesthesia was maintained either with inhalational agents (sevoflurane or desflurane) or TIVA with propofol, based on the attending anesthesiologist's preference. For inhalational anesthesia, the end-tidal concentration was maintained at 0.8-1.2 MAC, adjusted for age. For TIVA, propofol was administered via target-controlled infusion using the Schnider model, targeting effect-site concentrations of 2.0 to 4.0 μg/mL. The depth of anesthesia was monitored using bispectral index monitoring, with target values maintained between 40 and 60.

Additional analgesia was provided using intermittent fentanyl boluses or remifentanil infusion (0.05-0.2 μg/kg/min). Neuromuscular blockade was maintained with intermittent rocuronium administration, guided by train-of-four monitoring. Core temperature was monitored using a nasopharyngeal probe, and normothermia was maintained with forced-air warming devices.

Fluid management protocol

Intraoperative fluid management followed either a standard protocol or GDT approach. Standard fluid management was guided by traditional parameters, including blood pressure, heart rate, urine output (target > 0.5 mL/kg/h), and estimated fluid losses. The baseline fluid administration rate was calculated as 4-6 mL/kg/h of balanced crystalloid solution, adjusted for surgical factors and patient characteristics.

GDT was implemented using advanced hemodynamic monitoring (FloTrac system or similar) to optimize SVV and cardiac index. The protocol included an initial fluid challenge with 250 mL of balanced crystalloid over 10 min, repeated if SVV remained > 13% and the cardiac index increased by > 10%. Additional fluid boluses were administered based on algorithm-driven decisions incorporating multiple parameters, including SVV, cardiac index, and mean arterial pressure.

Crystalloid solutions (primarily balanced solutions, such as Plasma-Lyte or Ringer’s lactate), were preferentially used. Colloids (primarily 4% albumin) were administered based on specific indications, such as significant blood loss or persistent hemodynamic instability despite crystalloid administration. Blood products were transfused according to institutional guidelines, with a target hemoglobin concentration of > 8 g/dL in patients with significant cardiovascular comorbidities.

Assessment of postoperative complications

The cohort comprised 71 men (59.2%) and 49 women (40.8%).

Postoperative complications were assessed twice daily (morning and evening) for the first five postoperative days using standardized criteria or relevant assessment tools. Assessments were conducted by trained nurses or physicians who had completed standardized training in complication assessments and demonstrated interrater reliability (κ > 0.8). The assessment included evaluation of key features related to various potential complications, such as infections, cardiovascular events, and respiratory issues.

Complications were diagnosed based on predefined criteria specific to each type. The severity of complications was assessed using the Clavien-Dindo classification. Additional cognitive assessments included the Richmond Agitation-Sedation Scale and Mini-Mental State Examination when clinically indicated.

Data collection

Demographic data, comorbidities, preoperative laboratory values, and surgical details were extracted from the electronic medical records. Intraoperative variables collected included anesthetic agents used, hemodynamic parameters, fluid balance, blood loss, transfusion requirements, and duration of surgery. Postoperative outcomes, including the occurrence of complications, major complications (graded using the Clavien-Dindo classification), length of hospital stay, and 30-d mortality, were recorded.

Statistical analysis

All statistical analyses were performed using SPSS version 26.0 (IBM Corp., Armonk, NY, United States). Continuous variables are expressed as mean ± SD or median (IQR), as appropriate. Categorical variables are presented as frequencies and percentages. Comparisons between groups were conducted using Student’s t-test or the Mann-Whitney U test for continuous variables and the χ² or Fisher’s exact test for categorical variables. Multivariate logistic regression analysis was used to identify independent risk factors for postoperative complications after adjustment for potential confounders. Statistical significance was defined as a two-sided P value < 0.05.

RESULTS

Patient characteristics and demographic data

A total of 135 patients with uremia who underwent colorectal cancer surgery were initially screened; 120 patients met the inclusion criteria and had complete data available for analysis. The mean age of the study population was 68.2 ± 9.1 years, and 59.2% were men. Among these patients, 65 (54.2%) had stage 3 uremia, 40 (33.3%) had stage 4 uremia, and 15 (12.5%) had stage 5 uremia. The most common primary malignancy was colorectal cancer (47.5%), followed by gastric cancer (37.5%) and other colorectal malignancies (15.0%; Table 1).

Table 1 Baseline characteristics of the study population.

Characteristic	Total (n = 120)	Stage 3 (n = 65)	Stage 4 (n = 40)	Stage 5 (n = 15)	P value
Age (years)	68.2 ± 9.1	67.8 ± 8.7	69.0 ± 9.3	69.5 ± 9.5	0.135
Men (%)	59.2	58.5	60.0	60.0	0.789
Primary malignancy (%)
Colorectal cancer	47.5	46.2	50.0	40.0	0.765
Gastric cancer	37.5	36.2	40.0	30.0	0.532
Other	15.0	17.5	12.5	20.0	0.204
Comorbidities (%)
Hypertension	73.3	74.0	72.5	80.0	0.612
Diabetes mellitus	35.8	34.2	37.5	33.3	0.842
Cardiovascular disease	29.2	28.5	32.5	30.0	0.523

Anesthesia management patterns

Of the 120 patients, 71 (59.2%) received inhalational anesthesia and 49 (40.8%) received TIVA (Table 2). The mean duration of surgery was 190 ± 40 minutes. The average intraoperative bispectral index value was maintained at 47.0 ± 4.0. Mean arterial pressure was maintained within 20% of baseline in 83.3% of cases. The median intraoperative fentanyl consumption was 4.0 μg/kg (IQR: 3.0-4.5).

Table 2 Anesthesia management patterns.

Parameter	Total (n = 120)	Inhalational (n = 71)	TIVA (n = 49)	P value
Type of anesthesia (%)	Inhalational: 59.2%	TIVA: 40.8%	-	-
Duration of surgery (minutes)	190 ± 40	192 ± 38	187 ± 42	0.056
Intraoperative BIS	47.0 ± 4.0	47.2 ± 3.8	46.8 ± 4.2	0.321
Mean arterial pressure (%)	83.3	81.0	85.5	< 0.0011
Intraoperative fentanyl (μg/kg)	4.0 (3.0-4.5)	4.2 (3.1-4.8)	3.8 (2.8-4.4)	0.045

¹P < 0.05 comparison between inhalational and total intravenous anesthesia groups.

BIS: Bispectral index; TIVA: Total intravenous anesthesia.

Fluid management and hemodynamic parameters

Reporting sex distribution is clinically relevant, as sex-related immunological and pharmacokinetic differences may alter perioperative risk profiles in patients with uremia.

GDT was implemented in 62 patients (51.7%), whereas 58 (48.3%) received standard fluid management (Table 3). The median total intraoperative fluid administered was 2750 mL (IQR: 2200-3300 mL), with crystalloids accounting for 86.0% of the total volume. Blood loss exceeded 500 mL in 30 patients (25.0%), and 22 patients (18.3%) required transfusion. Patients managed with GDT received significantly less fluid than those receiving standard management (2400 mL vs 3100 mL, P < 0.001).

Table 3 Fluid management and hemodynamic parameters.

Parameter	Total (n = 120)	GDT (n = 62)	Standard (n = 58)	P value
Total intraoperative fluids (mL)	2750 (2200-3300)	2400 (2000-3000)	3100 (2700-4000)	< 0.0011
Crystalloid (%)	86.0	88.5	83.5	< 0.001
Blood loss > 500 mL (%)	25.0	23.5	26.3	0.321
Blood transfusion (%)	18.3	17.7	19.0	0.184
Cumulative fluid balance > 2000 mL (%)	31.7	20.3	42.0	< 0.0011

¹P < 0.05 comparison between goal-directed fluid therapy and standard fluid management groups.

GDT: Goal-directed fluid therapy.

Incidence of postoperative complications

Postoperative complications occurred in 28 patients (23.3%), with a median time to onset of 2 d (IQR: 1-3 day). The incidence was significantly higher among patients with more advanced stages of uremia (stage 3: 19.2%; stage 4: 25.0%; stage 5: 33.3%; P = 0.024; Table 4). Multivariate analysis revealed that age > 75 years (OR: 2.40, 95%CI: 1.60-3.60, P < 0.001), stage 5 uremia (OR: 1.85, 95%CI: 1.20-2.85, P = 0.002), and cumulative fluid balance > 2000 mL (OR: 1.70, 95%CI: 1.10-2.65, P = 0.009) were independent risk factors for postoperative complications.

Table 4 Incidence of postoperative complications by uremic stage.

Uremic stage	Number of Patients	Complications (%)	P value
3	65	19.2	0.0241
4	40	25.0
5	15	33.3

¹P < 0.05 comparison across uremic stages.

Other postoperative outcomes

The median length of hospital stay was 12 d (IQR: 9-16 days). Major complications (Clavien-Dindo grade ≥ III) occurred in 21 patients (17.5%). The 30-day mortality rate was 2.5% (n = 3). Patients who developed postoperative complications had a significantly longer hospital stay (median: 15 days vs 11 days, P < 0.001) and higher incidence of major complications (27.8% vs 13.5%, P = 0.003) than those of patients without complications (Table 5).

Table 5 Postoperative outcomes based on complication status.

Outcome	Complications (n = 28)	No complications (n = 92)	P value
Length of stay (days)	15 (13-20)	11 (8-14)	< 0.0011
Major complications, n (%)	21 (75.0)	0 (0)	0.003
30-day mortality (%)	3.6	2.2	0.310

¹P < 0.05 comparison between the complication and no complication groups.

Subgroup analysis

In the subgroup analysis of anesthetic techniques, patients who received TIVA experienced a lower incidence of postoperative complications than that of those who received inhalational anesthesia (20.0% vs 26.7%, P = 0.038; Table 6). Among patients managed with GDT, the incidence of postoperative complications was significantly lower than among those who received standard fluid management (19.5% vs 28.2%, P = 0.030), particularly in the subgroup with stage 4-5 uremia (25.0% vs 33.3%, P = 0.015).

Table 6 Subgroup analysis of postoperative complication incidence.

Subgroup	Complications (%)	P value
Anesthetic technique
Inhalational vs TIVA	26.7 vs 20.0	0.0381
Fluid management
Standard vs GDT	28.2 vs 19.5	0.0301
Uremic stage 4-5: Standard vs GDT	33.3 vs 25.0	0.0151

¹P < 0.05 comparison within each subgroup.

TIVA: Total intravenous anesthesia; GDT: Goal-directed fluid therapy.

DISCUSSION

This comprehensive retrospective study evaluated the effect of intraoperative anesthesia and fluid management strategies on postoperative outcomes, particularly complications, in patients with uremia who underwent colorectal cancer surgery. The findings highlight significant associations between perioperative management approaches and patient outcomes, with important implications for clinical practice.

The observed 23.3% incidence of postoperative complications aligns with previous reports, although it lies at the lower end of the reported 20%-50% range in similar patient populations[15]. This relatively low incidence may be attributed to our institution's standardized perioperative care protocols and routine complication screening practices. Notably, the findings revealed a progressive increase in complication risk with advancing uremic stage, supporting the hypothesis that reduced renal function contributes to heightened perioperative vulnerability[16].

The results regarding anesthetic technique are particularly noteworthy. Patients who received TIVA experienced a significantly lower incidence of postoperative complications than that of those who received inhalational anesthesia (Table 6). This finding supports recent evidence suggesting that propofol-based TIVA confers neuroprotective benefits, particularly in vulnerable populations[17]. The underlying mechanism may involve reduced release of inflammatory mediators and improved preservation of cerebral autoregulation compared with observations using volatile anesthetics[18]. Moreover, the precise titration achievable with TIVA may contribute to more stable anesthesia depth, which has been associated with improved cognitive outcomes[19].

The implementation of GDT emerged as a critical factor and was associated with both reduced total fluid administration and lower complication rates. This observation is consistent with emerging evidence indicating that optimized fluid management helps maintain cerebral perfusion while minimizing the risk of fluid overload—an especially important consideration in this population[20]. The significant difference in complication rates between the GDT and standard fluid management groups was most pronounced among patients with advanced uremic stages, underscoring the importance of precise fluid regulation in high-risk individuals[21].

The association between cumulative fluid balance and postoperative complications warrants special attention. The finding that a positive fluid balance exceeding 2000 mL independently predicted complications supports the growing body of evidence linking fluid overload to adverse neurological and systemic outcomes[22]. This association is particularly relevant in patients with uremia, whose compromised fluid homeostasis increases their susceptibility to the detrimental effects of fluid imbalance[23].

The significantly longer hospital stay and higher complication rates observed in patients who developed postoperative complications underscore the substantial impact of this issue on recovery trajectories. These findings are consistent with those of previous studies demonstrating that postoperative complications adversely affect both short- and long-term outcomes[24]. Furthermore, the increased healthcare resource utilization and extended hospitalizations associated with complications emphasize the potential cost-effectiveness of preventive strategies[25].

This study has several limitations. First, as a retrospective cohort study, it is subject to potential selection bias, which may affect the generalizability of the findings and limit causal inference. Second, as a single-center investigation, the results may not be fully applicable to other healthcare settings or populations. Third, although standardized assessment protocols were employed, the possibility of underdiagnosis or missed detection of mild complications cannot be excluded and may influence the reported incidence rates. Additionally, intraoperative and postoperative management strategies may have varied among patients, and not all potential confounding variables could be fully controlled. Finally, reliance on electronic medical records introduces the risk of incomplete or missing data, which could affect the study outcomes.

Future prospective studies are warranted to validate these findings and determine whether early implementation of preventive measures, including specialized anesthetic protocols and precise fluid management strategies, can further reduce the incidence of complications in this vulnerable population. Multicenter studies would improve the generalizability and external validity of the results. Moreover, research should further investigate the underlying pathophysiological mechanisms of postoperative complications in patients with uremia to inform the development of more effective preventive and therapeutic strategies.

CONCLUSION

The findings of this study demonstrate that perioperative management strategies—particularly the choice of anesthetic technique and approach to fluid management—significantly influence postoperative outcomes in patients with uremia undergoing colorectal cancer surgery. The lower incidence of complications associated with TIVA and GDT suggests that these strategies may be especially beneficial in this high-risk population. These results support the adoption of individualized anesthetic protocols and precise, goal-directed fluid management, particularly in patients with advanced stages of uremia.