Association of diaphragmatic ultrasound parameters with preoperative pulmonary function tests and postoperative respiratory complications in patients undergoing major abdominal surgeries: A prospective observational study

• Author Details:   
• Shreya Khatri
• Aarti Agarwal
• Sanjay Dhiraaj
• Hira Lal
• Rajneesh Kumar Singh
• Puneet Goyal ^*

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Background and Aims: Diaphragmatic dysfunction is an often-overlooked cause of respiratory compromise in postsurgical patients. Point-of-care ultrasonography (USG) is a valuable tool for real-time assessment of diaphragmatic excursion, thickness, and thickening fraction. This study aimed to evaluate the correlation between preoperative diaphragm ultrasound parameters and pulmonary function test (PFT) results, and their association with postoperative pulmonary complications (PPCs).

Methods: This prospective observational pilot study included 60 adult patients (aged 18–60 years, ASA I–III) undergoing elective major abdominal surgery. Preoperative PFTs were conducted one day prior to surgery, recording Breath Holding Time, Vital Capacity, Forced Vital Capacity, Peak Expiratory Flow Rate, and Maximum Inspiratory Capacity (MIC). Diaphragm ultrasound was performed to assess diaphragmatic excursion (left and right), thickness (at maximum inspiration and expiration), and thickening fraction. Postoperative pulmonary complications and the need for ventilatory support were recorded.

Results: There was a significant association (p < 0.05) between lower preoperative PFT and diaphragm ultrasound values and the requirement for postoperative ventilatory support. Among all measured parameters, MIC and left hemidiaphragm excursion demonstrated the highest diagnostic accuracy in predicting PPCs, with MIC <1.51 L showing >94% sensitivity and 100% specificity, and left diaphragmatic excursion <2.01 cm showing >88% sensitivity and >92% specificity.

Conclusion: Preoperative pulmonary function and diaphragm ultrasound parameters are significantly associated with the need for postoperative ventilatory support in patients undergoing major abdominal surgery. Diaphragm ultrasound correlates well with PFTs and can serve as a non-invasive predictive tool for identifying patients at risk of postoperative pulmonary complications.