European Journal of Cardiovascular Medicine

Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory lung condition characterized by persistent airflow limitation and a chronic inflammatory response in the airways and lung parenchyma. Patients with COPD are particularly vulnerable to perioperative complications, most notably postoperative respiratory failure, due to compromised pulmonary reserves and impaired gas exchange mechanisms. This elevated risk frequently necessitates extended periods of ventilatory support postoperatively, as compared to individuals without underlying pulmonary pathology [1,2]. Prolonged mechanical ventilation, however, is not without consequences; it has been associated with ventilator-induced lung injury (VILI), barotrauma, and an increased incidence of ventilator-associated pneumonia (VAP), all of which contribute to worsening patient outcomes [3].

These complications not only prolong the duration of intensive care unit (ICU) and hospital stays but also significantly elevate the overall cost of treatment. The need for meticulous perioperative planning and postoperative care in this population underscores the importance of multidisciplinary coordination between anesthesiologists and surgeons [4]. Early identification of high-risk COPD patients through comprehensive preoperative evaluation is therefore essential to optimize outcomes.

COPD severity is typically classified using spirometric criteria, particularly the forced expiratory volume in the first second (FEV1), which remains the cornerstone for staging the disease. According to established guidelines, COPD is stratified into four stages: mild, moderate, severe, and very severe, based on the percentage of predicted FEV1 values. This stratification not only aids in guiding long-term management but also serves as a valuable tool for perioperative risk assessment [5].

Despite the clinical significance of this association, there remains a paucity of evidence exploring the impact of COPD severity on postoperative pulmonary complications in specific surgical populations, such as those undergoing spinal procedures. Given this background, the present study was designed to investigate the correlation between the degree of COPD severity, as defined by spirometric parameters, and the incidence of postoperative respiratory failure in patients undergoing spinal surgery. By elucidating this relationship, the study aims to contribute to the growing body of evidence supporting individualized perioperative management strategies in patients with compromised pulmonary function.

This observational study was carried out at a tertiary care center, involving a total of 40 patients previously diagnosed with COPD who subsequently underwent spinal surgery. The selection of study participants was based on retrospective data retrieved from the hospital's medical records department. The extracted information included demographic profiles, results from pulmonary function tests (spirometry), arterial blood gas (ABG) analysis, pre-existing comorbid conditions, postoperative outcomes, and other relevant clinical variables.

Patients were excluded from the study if they underwent emergency surgical procedures, did not have documented pulmonary function test results, or presented with additional severe systemic illnesses that could confound respiratory outcomes.

The diagnosis of COPD was established in accordance with established clinical criteria, wherein the post-bronchodilator ratio of forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) was calculated. A ratio of less than 0.70 after bronchodilator administration was indicative of airflow obstruction consistent with COPD [6]. Furthermore, the severity of the disease was categorized based on the post-bronchodilator FEV1 percentage of the predicted value, as outlined in standard clinical guidelines. Accordingly, patients were stratified into four distinct categories: mild, moderate, severe, and very severe COPD [6].

The principal outcome evaluated in this study was the incidence of postoperative respiratory failure occurring within the first seven days following the surgical procedure [6]. This was defined based on clinical and laboratory parameters consistent with accepted diagnostic standards for respiratory insufficiency.

Data were entered and analyzed using the Statistical Package for the Social Sciences (SPSS), version 23.0. Categorical variables were summarized and expressed as frequencies and percentages to describe the distribution of patient characteristics and outcomes.

A total of 67 COPD patients undergoing surgery under general anesthesia were included in the study. The majority of participants were male, and most were aged between 51 and 70 years. Hypertension was the most common comorbidity, followed by diabetes and history of stroke. A small proportion of patients were active smokers. The detailed demographic and clinical characteristics of the study population are presented in Table 1.

Table 1: Demographic and clinical profile of COPD patients

Regarding surgical parameters, cervical spine surgeries were more frequent than lumbar procedures. The average duration of anesthesia across the cohort was approximately three hours. These details are outlined in Table 2.

Table 2: Surgical details of COPD patients

When stratified according to the severity of postoperative respiratory failure, no statistically significant associations were observed between gender, type of surgery, or comorbidities such as hypertension and diabetes (Table 3). Although smoking history appeared exclusively in the very severe group, the association did not reach statistical significance. Additionally, the mean duration of anesthesia tended to be longer in the mild group and progressively declined with increasing severity, but this trend was not statistically significant.

Table 3: Association of severity of respiratory failure with various parameters

The frequency of complications varied across severity groups. Pulmonary infection and respiratory muscle failure occurred across all categories but showed no consistent trend with increasing severity. Notably, the requirement for postoperative endotracheal intubation was more frequent in the very severe group. Furthermore, both length of hospital stay and extubation time increased progressively with the severity of respiratory failure, as shown in Table 4.

Table 4: Risk factors for Respiratory failure in COPD patients under GA

Pulmonary infections were observed across all categories of respiratory failure severity among COPD patients undergoing spinal surgery, with relatively comparable distribution in mild to severe cases. However, a lower occurrence was noted in the very severe group (Table 4). This pattern reinforces the well-documented susceptibility of COPD patients to postoperative lower respiratory tract infections, likely due to impaired mucociliary clearance, chronic airway inflammation, and weakened host defense mechanisms. These risks may be further amplified in the setting of spinal surgery due to postoperative immobility, diminished respiratory effort, and the common use of endotracheal intubation or mechanical ventilation, which may promote colonization by pathogenic organisms [7].

The observed increase in postoperative endotracheal intubation rates and prolonged extubation times in patients with more severe respiratory compromise (Table 4) highlights the clinical impact of underlying pulmonary dysfunction on recovery trajectories. Moreover, the progressive increase in hospital stay duration with worsening respiratory severity underscores the burden these complications place on healthcare resources and patient outcomes.

Although the study did not incorporate preoperative spirometric values, the role of pulmonary function testing (PFT), particularly spirometry, remains crucial in perioperative risk stratification. Spirometric indices such as FEV₁ and FEV₁/FVC are essential for assessing airflow limitation and predicting postoperative respiratory outcomes [8,9]. Identifying patients at increased risk for respiratory failure enables preemptive optimization and individualized anesthetic planning.

It is important to acknowledge that the clinical utility of spirometry depends on several interrelated factors, including operator proficiency, equipment calibration, and patient cooperation. Inadequate technique or effort can lead to underestimation of disease severity, thereby impairing the precision of risk prediction and perioperative management [10].

While prior studies have advocated for the integration of arterial blood gas (ABG) analysis—especially the assessment of PaO₂—to enhance perioperative evaluation, this parameter could not be assessed in the present study due to limitations in clinical documentation and the retrospective design [11–13].

Several limitations should be considered. The retrospective nature of data collection may have introduced information bias or missing data, particularly with regard to perioperative monitoring parameters. Additionally, the single-center setting limits the generalizability of findings, as institutional protocols, surgical expertise, and perioperative care practices may vary across healthcare systems. Future multicentric studies with prospective designs and inclusion of PFT and ABG parameters are warranted to further delineate the interplay between COPD severity and postoperative pulmonary outcomes.

Although the present study did not establish a statistically significant association between COPD severity and the incidence of postoperative respiratory failure, the observed trends underscore the complexity of perioperative respiratory outcomes in this high-risk group. Future research should involve prospective multicentric studies employing a standardized set of diagnostic and prognostic parameters, including arterial blood gas analysis and dynamic lung function indices. This will facilitate a more comprehensive understanding of the pathophysiological interplay between COPD and postoperative complications, ultimately guiding the development of more effective and individualized perioperative care strategies.

1. Licker MJ, Widikker I, Robert J, Frey JG, Spiliopoulos A, Ellenberger C, et al. Operative mortality and respiratory complications after lung resection for cancer: impact of chronic obstructive pulmonary disease and time trends. Ann Thorac Surg. 2006;81:1830–7. doi:10.1016/j.athoracsur.2005.11.048.
2. Nafiu OO, Ramachandran SK, Ackwerh R, Tremper KK, Campbell DA, Stanley JC. Factors associated with and consequences of unplanned post-operative intubation in elderly vascular and general surgery patients. Eur J Anaesthesiol. 2011;28:220–4.
3. Gattinoni L, Tonetti T, Cressoni M, Cadringher P, Herrmann P, Moerer O, et al. Ventilator-related causes of lung injury: the mechanical power. Intensive Care Med. 2016;42:1567–75.
4. Halbert RJ, Natoli JL, Gano A, Badamgarav E, Buist AS, Mannino DM. Global burden of COPD: systematic review and meta-analysis. Eur Respir J. 2006;28:523–32.
5. Mirza AW, Kaur D, Chhetty YK. General anaesthesia for patients with chronic obstructive pulmonary disease undergoing spinal surgery and postoperative respiratory failure: an observational study. Eur J Cardiovasc Med. 2022;12(4):232–4.
6. Vogelmeier CF, Criner GJ, Martinez FJ, Anzueto A, Barnes PJ, Bourbeau J, et al. Global strategy for the diagnosis, management, and prevention of chronic obstructive lung disease: 2017 report. GOLD executive summary. Am J Respir Crit Care Med. 2017;195:557–82.
7. Wang JS. Pulmonary function tests in preoperative pulmonary evaluation. Respir Med. 2004;98:598–605.
8. Yang CK, Teng A, Lee DY, Rose K. Pulmonary complications after major abdominal surgery: National Surgical Quality Improvement Program analysis. J Surg Res. 2015;198(2):441–9.
9. Xiao F, Yang J, Fan R. Effects of COPD on in‐hospital outcomes of transcatheter aortic valve implantation: results from the National Inpatient Sample database. Clin Cardiol. 2020;43:1524–33.
10. Sabaté S, Mazo V, Canet J. Predicting postoperative pulmonary complications. Curr Opin Anaesthesiol. 2014;27(2):201–9.
11. Vogelmeier CF, Criner GJ, Martinez FJ, Anzueto A, Barnes PJ, Bourbeau J, et al. Global strategy for the diagnosis, management and prevention of chronic obstructive lung disease: 2017 report. GOLD executive summary. Am J Respir Crit Care Med. 2017;195:557–82.
12. Upchurch GR, Proctor MC, Henke PK, Zajkowski P, Riles EM, Ascher MS, et al. Predictors of severe morbidity and death after elective abdominal aortic aneurysmectomy in patients with chronic obstructive pulmonary disease. J Vasc Surg. 2003;37:594–9.
13. Attaallah AF, Vallejo MC, Elzamzamy OM, Mueller MG, Eller WS. Perioperative risk factors for postoperative respiratory failure. J Perioper Pract. 2019;29:49–53.