European Journal of Cardiovascular Medicine

Postoperative respiratory complications (PRCs) are among the most common and preventable causes of postoperative morbidity and mortality [1]. These complications range from mild hypoxia to life-threatening pneumonia and respiratory failure requiring re-intubation and mechanical ventilation [2].

Patients undergoing general anesthesia are at particular risk due to airway manipulation, residual neuromuscular blockade, and the systemic effects of anesthetic agents on respiratory drive [3]. Although numerous risk factors have been postulated, including age, obesity, smoking, comorbidities, and surgical type, a clear understanding of modifiable vs. non-modifiable risks remains crucial for risk stratification and perioperative planning [4,5].

This study aims to identify key preoperative and intraoperative predictors of PRCs in adult patients undergoing elective procedures under general anesthesia in a tertiary care center.

2.1 Study Design

A prospective, observational cohort study was conducted at [Institution Name] between [Start Date] and [End Date] after obtaining Institutional Ethics Committee approval (Ref: IEC/2023/112).

2.2 Participants

Inclusion Criteria:

• Adults (≥18 years) undergoing elective surgery under general anesthesia
• ASA Physical Status I–IV

Exclusion Criteria:

• Emergency surgery
• Preoperative mechanical ventilation
• Surgery under regional anesthesia only

2.3 Data Collection

Variables recorded:

• Demographic: age, gender, BMI, smoking status
• Clinical: ASA class, comorbidities (COPD, asthma, diabetes, cardiac disease), Mallampati score
• Surgical/Anesthetic: type and duration of surgery, use of opioids, muscle relaxants, intraoperative ventilation parameters, neuromuscular monitoring, and reversal agents

2.4 Outcome Definition

PRCs were defined as one or more of the following within 72 hours of surgery:

• Oxygen desaturation (SpO₂ <90%)
• Bronchospasm
• Pneumonia (clinical + radiologic + leukocytosis)
• Re-intubation or need for mechanical ventilation

2.5 Statistical Analysis

Statistical analysis was performed using SPSS v27. Categorical variables were analyzed using Chi-square/Fisher’s test. Continuous variables were compared using t-test or Mann–Whitney U test. Logistic regression identified independent risk factors (p < 0.05 considered significant).

3.1 Demographics and Incidence

Out of 300 patients, 48 (16%) developed PRCs. Table 1 compares characteristics of patients with and without PRCs.

Table 1. Baseline Characteristics

3.2 Types of Respiratory Complications

Figure 1 shows the distribution of PRC types among affected patients.

Figure 1. Frequency of Respiratory Complications
(Bar chart: Hypoxia 58%, Pneumonia 21%, Bronchospasm 13%, Re-intubation 8%)

3.3 Multivariate Analysis

Table 2 shows independent predictors of PRC after logistic regression.

Table 2. Independent Predictors of Postoperative Respiratory Complications

Our findings highlight that PRCs occurred in 16% of patients undergoing elective surgery under general anesthesia, which is consistent with previous reports estimating an incidence between 5%–20% depending on population and definitions used [6,7].

Age over 65 years emerged as a significant non-modifiable risk factor, likely due to reduced respiratory reserve, impaired mucociliary clearance, and decreased cough reflex in older adults [8]. ASA class III/IV and chronic respiratory disease (COPD or asthma) also independently increased the risk of PRCs, reinforcing the importance of thorough preoperative respiratory assessment in these populations [9,10].

Smoking was another strong predictor, likely contributing to impaired gas exchange, reactive airway changes, and increased sputum production [11]. Several studies suggest smoking cessation at least 4–8 weeks before surgery may reduce complications, a recommendation that should be reinforced during pre-anesthetic evaluation [12].

Intraoperative factors like surgery duration >3 hours and inadequate neuromuscular blockade reversal significantly increased PRC risk. Residual neuromuscular blockade is associated with upper airway obstruction, hypoventilation, and aspiration risk in the immediate postoperative period [13,14]. Neuromuscular monitoring and the use of reversal agents such as sugammadex (where available) should be considered to mitigate this risk.

Interestingly, obesity (BMI ≥30) was not significantly associated with PRC in our cohort, although other studies have suggested a modest risk elevation [15]. This may be due to selection bias or effective perioperative respiratory care protocols in our center.

The study is limited by its single-center design and exclusion of emergency surgeries. Also, long-term respiratory outcomes and ICU admissions beyond 72 hours were not assessed.

Postoperative respiratory complications are common and multifactorial in patients undergoing general anesthesia. Risk stratification should include age, ASA grade, preexisting pulmonary disease, smoking, surgery duration, and attention to neuromuscular recovery. Targeted interventions addressing modifiable factors may significantly reduce respiratory morbidity.

Acknowledgements

We thank the Department of Anesthesiology and Surgery at for their cooperation. Special thanks to Dr.Sankalp Verma for statistical support.

Conflicts of Interest

None declared.

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