European Journal of Cardiovascular Medicine

Chronic Obstructive Pulmonary Disease (COPD) affects over 300 million people globally and represents a major cause of morbidity and mortality worldwide. ^[1] It is characterized by persistent airflow limitation and an enhanced chronic inflammatory response in the airways and lungs. ^[2] Surgical interventions in patients with COPD pose unique challenges due to compromised pulmonary function and increased susceptibility to postoperative pulmonary complications (PPCs). ^[3]

PPCs, including pneumonia, atelectasis, bronchospasm, respiratory failure, and prolonged mechanical ventilation, contribute significantly to postoperative morbidity, longer hospital stays, and higher healthcare costs. ^[4] The incidence of PPCs in the general population undergoing non-cardiac surgery ranges from 5% to 10%, but this increases substantially in patients with underlying pulmonary diseases, particularly COPD. ^[5] A systematic review reported an approximate 30% risk of PPCs in patients with moderate-to-severe COPD undergoing upper abdominal or thoracic surgeries. ^[6]

Numerous risk factors influence the development of PPCs. These include advanced age, reduced preoperative forced expiratory volume in one second (FEV1), poor functional status, smoking, emergency surgery, duration and type of anesthesia, and the nature of the surgical procedure. ^[7,8] General anesthesia, especially with endotracheal intubation, may impair mucociliary clearance and increase the risk of bronchospasm and infection. ^[9] In contrast, regional anesthesia techniques such as epidural or spinal blocks have been associated with better postoperative outcomes in select patient populations. ^[10]

Despite advances in perioperative care, the burden of PPCs remains high in COPD patients. There is a critical need for studies that quantify this risk and evaluate modifiable factors that can reduce postoperative morbidity. Prospective observational studies offer the advantage of systematically capturing perioperative variables and outcomes in a real-world clinical setting.

This study was designed to evaluate the incidence of PPCs in COPD patients undergoing elective non-cardiac surgery and to identify key risk factors associated with poor outcomes. By focusing on a prospective patient cohort and assessing intraoperative and postoperative variables, this study aims to provide clinical insights that may guide anesthetic and surgical decision-making in patients with compromised pulmonary reserve.

In addition, this research investigates whether the use of regional anesthesia and optimization of pulmonary function preoperatively can reduce the incidence of PPCs in this high-risk population. These findings may contribute to developing standardized protocols for preoperative risk stratification and postoperative management in COPD patients.

Aim: To evaluate the incidence, risk factors, and outcomes of postoperative pulmonary complications (PPCs) in patients with Chronic Obstructive Pulmonary Disease (COPD) undergoing surgery. Objectives: To determine the incidence of postoperative pulmonary complications in COPD patients following various surgical procedures,

This prospective observational study was conducted in the Department of Respiratory Medicine, and Anaesthesiology, Sapthagiri Institute of Medical Sciences and Research Centre from April 2024 to March 2025.

Study Population

The study included patients aged 40–75 years with a confirmed diagnosis of Chronic Obstructive Pulmonary Disease (COPD), as per the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. All participants were scheduled to undergo elective non-cardiac surgeries under general or regional anesthesia.

Inclusion Criteria

• Diagnosed cases of COPD confirmed by spirometry (FEV₁/FVC ratio < 0.70 after bronchodilator).
• Age between 40 and 75 years.
• American Society of Anesthesiologists (ASA) physical status II or III.
• Elective non-cardiac surgical procedures (including abdominal, orthopedic, urologic, and gynecologic surgeries).
• Patients providing written informed consent.

Exclusion Criteria

• Emergency surgical cases.
• Patients with concurrent restrictive lung disease or bronchiectasis.
• Known diagnosis of pulmonary tuberculosis or active lung infection.
• ASA physical status IV or higher.
• History of recent myocardial infarction (<6 months).
• Hemodynamically unstable patients.
• Patients requiring postoperative mechanical ventilation due to surgical indication.

Preoperative Evaluation

All enrolled patients underwent thorough preoperative evaluation including medical history, physical examination, chest radiograph, ECG, and baseline laboratory investigations. Pulmonary function tests (PFTs) were conducted in all cases to assess FEV₁, FVC, and FEV₁/FVC ratio. Arterial blood gases were also obtained when clinically indicated.

Optimization measures for COPD patients included smoking cessation at least two weeks prior, bronchodilator therapy, corticosteroids (in patients with frequent exacerbations), chest physiotherapy, and antibiotic therapy when signs of infection were present.

Sample Size Calculation:

The sample size was calculated based on the expected incidence of postoperative pulmonary complications (PPCs) in patients with COPD undergoing surgery. Assuming an estimated incidence of PPCs of 30%, with a power of 80% and an alpha error of 5%, a minimum sample size of 100 patients was determined to detect a clinically significant difference in postoperative outcomes between patients with and without PPCs. Accordingly, 100 COPD patients undergoing surgery were enrolled, of whom 38 (38%) developed PPCs and 62 (62%) did not.

Intraoperative Management

Patients were grouped based on the type of anesthesia received: general anesthesia (GA) or regional anesthesia (RA). Standard monitoring included ECG, pulse oximetry, capnography, and non-invasive blood pressure. In GA cases, drugs used for induction, ventilation strategy, and airway management were recorded. In RA cases, the level and duration of block and intraoperative sedation were documented.

All intraoperative and immediate postoperative parameters including blood loss, duration of surgery, fluid balance, and hemodynamic stability were recorded.

Postoperative Monitoring

Patients were observed in the Post-Anesthesia Care Unit (PACU) and then shifted to surgical wards or Intensive Care Unit (ICU) as per clinical condition. All patients were followed for seven days postoperatively for the development of pulmonary complications such as:

• Atelectasis
• Pneumonia
• Bronchospasm
• Respiratory failure requiring mechanical ventilation
• Hypoxemia (SpO₂ < 90% on room air)

Chest auscultation, respiratory rate, oxygen saturation, chest X-ray, arterial blood gas analysis and sputum culture (if applicable) were used to confirm the diagnosis of complications.

Statistical Analysis

Data were entered and analyzed using SPSS software version 22. Continuous variables were expressed as mean ± standard deviation and categorical variables as frequency and percentage. Chi-square test and unpaired t-tests were used to compare qualitative and quantitative variables respectively. A p-value <0.05 was considered statistically significant.

Table 1: Patient Factors Associated with PPCs

In Table 1, Patients who developed PPCs were significantly older (mean age 66.1 ± 6.3 years vs. 61.2 ± 7.1 years; p = 0.013) with a male-to-female ratio of approximately 3:1. There was also a higher prevalence of comorbidities such as diabetes and hypertension among those with PPCs. patients with FEV₁ < 50% predicted had a significantly higher incidence of PPCs (p < 0.01). Mean FEV₁ in patients with complications was 47.6% compared to 62.3% in those without.

Table 2: Anesthesia Type and PPC Risk

In Table 2, Regional anesthesia was associated with a lower PPC rate (22%) compared to general anesthesia (46%) with a statistically significant difference (p = 0.021).

Table 3: Surgery-Related Risk Factors

In table 3, Upper abdominal and thoracic procedures had the highest incidence of PPCs (above 50%), while lower abdominal and peripheral surgeries had fewer complications.

Table 4: Intraoperative Factors

In table 4, Longer surgical duration (>3 hours) and higher estimated blood loss (>500 mL) were independently associated with higher PPCs.

Table 5: Outcomes

In Table 5, displays postoperative variables. Patients who developed PPCs had longer hospital stays (mean 9.4 ± 2.3 days) compared to those without (5.6 ± 1.8 days), with a significant p value < 0.001.

Table 6: Incidence of Postoperative Pulmonary Complications (PPCs)

Postoperative pulmonary complications were observed in 38 patients (38%). The most common complications included:

• Atelectasis (16%)
• Bronchospasm (12%)
• Pneumonia (10%)
• Hypoxemia (9%)
• Respiratory failure requiring re-intubation or non-invasive ventilation (5%)

Postoperative pulmonary complications (PPCs) remain a significant concern in patients with COPD undergoing non-cardiac surgeries. In this prospective observational study, we observed a 38% incidence of PPCs, which aligns with earlier findings reporting complication rates ranging from 30% to 50% in similar populations. ^{[11, 12]}

The high frequency of PPCs in our study underscores the vulnerability of COPD patients in the perioperative setting. One of the most notable findings was the association between reduced preoperative lung function and PPCs. Patients with FEV₁ < 50% predicted had nearly double the risk of complications, supporting evidence from Smetana et al., who identified impaired spirometry as a strong predictor of PPCs. ^[13]

Older age was another significant risk factor in our analysis. Patients over 65 were more likely to develop complications, echoing results from Lawrence and Page, ^[14] who found age to be an independent predictor due to age-related changes in lung compliance and respiratory muscle strength. Similarly, comorbid conditions like diabetes and hypertension increased the risk of PPCs, consistent with studies by Canet et al. ^[15] and Qaseem et al. ^[16] who emphasized the additive risk of systemic illness.

The type of surgery played a pivotal role, with upper abdominal and thoracic procedures resulting in the highest rates of PPCs. This is attributable to diaphragmatic splinting, reduced lung volumes, and impaired mucociliary clearance postoperatively. ^[17] Warner et al. ^[18] reported a 40% incidence of PPCs following upper abdominal surgeries, closely matching our findings.

An important observation from this study was the beneficial effect of regional anesthesia (RA) in reducing PPC incidence. Patients who underwent surgery under RA had significantly fewer complications compared to those who received general anesthesia (GA). This observation supports previous findings by McAlister et al.^9^ and Licker et al., ^[20] who reported that avoiding intubation and systemic sedatives can improve pulmonary outcomes in high-risk patients.

Prolonged surgery and higher blood loss were also linked to an increased incidence of complications. This mirrors the conclusions of Miskovic and Lumb, ^[21] who stated that extended operative times and fluid shifts can impair oxygenation and promote pulmonary edema, increasing susceptibility to infections.

Furthermore, patients with PPCs had significantly longer hospital stays. This economic and clinical burden has been documented by Mullen et al., ^[21] who highlighted the increased resource utilization in this group. Importantly, no postoperative deaths occurred in our cohort, but five patients required ventilatory support, stressing the need for early intervention and pulmonary optimization.

These findings suggest that effective preoperative assessment, including spirometry and risk stratification, should be mandatory for COPD patients. Strategies such as smoking cessation, bronchodilator therapy, and choosing RA when feasible can significantly reduce morbidity.

Although this study provides valuable insights, it has some limitations. The sample size was relatively modest, and outcomes were only followed for 7 days postoperatively. Longer follow-up might reveal late-onset complications. Nonetheless, the prospective design and standardized PPC criteria enhance the reliability of our findings.

The study identified key predictors of PPCs, including advanced age, reduced FEV₁ (<50%), general anesthesia, upper abdominal or thoracic surgeries, prolonged surgical duration, and coexisting comorbidities. Importantly, the use of regional anesthesia and preoperative pulmonary optimization were associated with lower complication rates, suggesting practical interventions that can be integrated into perioperative care. Early identification of high-risk patients through spirometry, comprehensive preoperative evaluation, and tailored anesthetic approaches are essential to reduce PPCs in this vulnerable population.

By emphasizing a multidisciplinary approach to perioperative management, including anesthesiologists, surgeons, and pulmonologists, patient outcomes can be improved while minimizing healthcare burdens. Future research with larger cohorts and longer follow-up will help further refine clinical pathways for managing COPD patients undergoing surgery.

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