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NCT Number: NCT06982911

Comparison of Postoperative Pulmonary Complications Between Smokers and Nonsmokers

This is a prospective observational study designed to evaluate the effect of smoking on early postoperative respiratory symptoms such as cough, airway secretions, and wheezing in adult patients undergoing elective abdominal surgery. Participants will be divided into two groups based on smoking history. The study aims to assess the incidence of minor pulmonary complications-such as increased secretions requiring suctioning, oxygen need, and early respiratory discomfort-within the first 24 hours after surgery. Data will be collected on parameters including secretion volume, oxygen saturation, aspiration frequency, and presence of cough or wheezing. The results will help determine whether active smoking is associated with a higher frequency of early postoperative pulmonary events.

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Key information

Conditions

Coughing Behavior Cough Pathologic Processes Pathological Conditions, Signs and Symptoms Post Operative Complications Postoperative Complications Respiration Disorders Respiratory Sounds Respiratory Tract Diseases Signs and Symptoms Signs and Symptoms, Respiratory Smoking Smoking, Tobacco Tobacco Smoking Tobacco Use Wheezing

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Gazi Yaşargil Training and Research Hospital

Diyarbakır, 21070, Turkey (Türkiye)

About this study

Cigarette smoking is a well-established risk factor for adverse postoperative outcomes, including respiratory complications. However, many studies have primarily focused on major complications such as pneumonia, reintubation, or prolonged mechanical ventilation, often underestimating early and subtle pulmonary effects of smoking. This study aims to fill that gap by evaluating early minor postoperative pulmonary events-specifically cough, airway secretions, and wheezing-within the first 24 hours after extubation in adult patients undergoing elective abdominal surgery.

The study is designed as a prospective observational cohort conducted in a single tertiary-care hospital. Adult patients (aged 18-65) undergoing elective abdominal surgery under general anesthesia will be included. Participants will be classified into two groups based on smoking history: current smokers and non-smokers. The primary outcome is the occurrence of early minor pulmonary complications, including secretion burden requiring aspiration, Peripheral Oxygen Saturation(SpO₂ ) desaturation (SpO₂ <90%), presence of audible wheezing, and persistent postoperative cough. These events will be documented by trained clinical staff using standardized clinical criteria and data collection forms.

The hypothesis of this study is that active smokers are more likely to develop early minor pulmonary complications within the first 24 hours after surgery compared to non-smokers. The findings will contribute to a better understanding of early perioperative respiratory risk among smoking patients and may support the refinement of risk assessment and preoperative counseling.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age between 18 and 65 years
  • Undergoing elective abdominal surgery under general anesthesia
  • ASA physical status I-II-III
  • Able to provide informed consent
  • Classified as either active smoker (≥10 pack-years) or nonsmoker (never smoked or quit >1 year ago)

Exclusion criteria

  • Diagnosed chronic pulmonary disease (e.g., Obstructive Sleep Apnea, asthma, Chronic Obstructive Pulmonary Disease)
  • Acute respiratory tract infection within the past 30 days
  • Morbid obesity (Body Mass Index >35 kg/m²)
  • Emergency surgery
  • Pregnancy or breastfeeding
  • Refusal to participate

Treatment and study plan

Primary outcomes

  1. Incidence of Early Postoperative Pulmonary Complications Within 24 Hours After Surgery

    Time frame: Within the first 24 hours after extubation

    The primary outcome is defined as the presence of at least one of the following respiratory findings within 24 hours after extubation: (1) increased airway secretions requiring aspiration, (2) persistent cough, (3) audible wheezing, or (4) oxygen desaturation below 90% on room air. These events will be documented by trained clinical staff using a standardized data collection form. Each patient will be assessed continuously for the first 6 hours and again at the 24th postoperative hour. The incidence of these pulmonary complications will be compared between smoking and nonsmoking patients.

Secondary outcomes

  1. Number of Suctions Required for Airway Secretion Clearance Within 6 Hours After Extubation

    Time frame: Within the first 1 hours after extubation

    This outcome measures the total number of suctioning procedures required to clear airway secretions during the first 6 hours after extubation. Suctioning is performed only when visible or audible secretions are present and is recorded by trained clinical staff using a standardized protocol.

  2. Oxygen Desaturation Events Below 90% Within the First 24 Hours After Surgery

    Time frame: Within the first 24 hours after extubation

    This outcome tracks the number and duration of oxygen desaturation episodes defined as saturation(SpO₂) falling below 90% on room air within the first 24 hours after extubation. Each event is recorded by trained clinical personnel using pulse oximetry. Desaturation episodes that are corrected by airway maneuvers or supplemental oxygen are noted.

  3. Association Between Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) Risk Score and Postoperative Pulmonary Complications

    Time frame: Within the first 24 hours after surgery

    The Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score will be calculated preoperatively for all included patients using seven validated clinical parameters (age, preoperative saturation (SpO2), respiratory infection in the last month, preoperative anemia, surgical incision type, duration of surgery, and emergency status). This score will be evaluated as a secondary outcome to assess its correlation with the incidence of early postoperative pulmonary complications (PPCs). The score will also be included in multivariate analysis models and ROC curve analysis to determine predictive value and optimal cutoff thresholds.

Sponsors and collaborators

Lead sponsor

mehmet özkılıç

Other

Registry information

Official study title

Comparison of Postoperative Pulmonary Complications Between Smokers and Nonsmokers: A Prospective Cohort Study

Acronym: MINOPPC

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
May 21, 2025
Registry last updated
Aug 3, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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