Prediction of Difficult Airway in Cesarean Section Using Preoperative Airway Assessment Tests (OB-DIFF-AIRWAY)

Evaluation of the Reliability of Preoperative Airway Assessment Tests in Predicting Difficult Airway Management in Obstetric Patients Undergoing Cesarean Section

This observational study (OB-DIFF-AIRWAY: Obstetric Difficult Airway Study) aimed to evaluate the accuracy of commonly used preoperative airway assessment tests in predicting difficult airway management in obstetric patients undergoing cesarean section. Difficult airway remained a significant cause of anesthesia-related complications, particularly in pregnant patients due to physiological and anatomical changes.

Adult pregnant women scheduled for elective or urgent cesarean section underwent standard preoperative airway assessment, including Mallampati classification, thyromental distance, interincisor distance, neck circumference, and other routine clinical evaluations. Airway management during anesthesia was performed according to standard clinical practice. No additional intervention was applied for the purpose of the study.

The relationship between preoperative airway assessment findings and actual airway management difficulty was analyzed. The results of this study may help improve preoperative airway evaluation strategies and enhance patient safety in obstetric anesthesia.

Study Overview

• Status: Completed
• Conditions: Airway Management; Difficult Airway; Obstetric Anesthesia
• Intervention / Treatment: Other: No intervention (observational study)

Detailed Description

Difficult airway management is one of the most critical challenges in anesthetic practice and is associated with increased morbidity and mortality. Obstetric patients represent a particularly high-risk population due to pregnancy-related physiological changes such as airway edema, weight gain, reduced functional residual capacity, and increased oxygen consumption. Despite routine use of various preoperative airway assessment tests, their predictive value in obstetric patients remains controversial.

This prospective observational study was conducted to evaluate the reliability of commonly used preoperative airway assessment tests in predicting difficult airway management in patients undergoing cesarean section. The study was performed at Akdeniz University Hospital between August 23, 2023, and August 23, 2024.

Adult obstetric patients scheduled for elective or urgent cesarean section under anesthesia were included. Patients with known airway pathology, prior difficult airway history requiring advanced airway techniques, or incomplete airway assessment data were excluded according to predefined criteria.

Preoperative airway assessment was performed as part of routine anesthetic evaluation and included Mallampati classification, thyromental distance, interincisor distance, neck circumference, and other standard clinical parameters. No additional procedures or interventions were introduced for research purposes. Anesthetic management and airway techniques were determined by the attending anesthesiologist in accordance with institutional standards.

Airway management difficulty was recorded intraoperatively based on predefined clinical criteria, including difficulty with mask ventilation, laryngoscopy, or tracheal intubation. The association between preoperative airway assessment findings and observed airway difficulty was analyzed using appropriate statistical methods. Difficult airway management was defined as the presence of at least one of the following predefined intraoperative criteria:

difficult mask ventilation (Han classification ≥ 3), difficult laryngoscopy (Cormack-Lehane grade III-IV), or failure of tracheal intubation on the first attempt.

Patients were enrolled using a consecutive non-probability sampling approach, including all eligible obstetric patients undergoing cesarean delivery during the study period.

The sample size was determined by the consecutive inclusion of all eligible patients undergoing cesarean delivery at the study center during the predefined study period.

The primary objective of the study was to assess the predictive value of individual and combined airway assessment tests for difficult airway management in obstetric patients. Secondary objectives included identifying potential risk factors associated with airway difficulty and evaluating the overall incidence of difficult airway in the study population.

The findings of this study are expected to contribute to improved preoperative airway evaluation and risk stratification in obstetric anesthesia, thereby enhancing patient safety and clinical outcomes.

• Study Type: Observational
• Enrollment (Actual): 546

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Türkiye
    • Antalya, Türkiye, Turkey (Türkiye), 07000
      • Akdeniz University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adult pregnant women aged 18 years and older who underwent elective or urgent cesarean section at a tertiary university hospital. All participants received standard preoperative airway assessment as part of routine anesthetic care.

Description

Inclusion Criteria:

• Adult obstetric patients aged 18 years or older
• Scheduled for elective or urgent cesarean section
• Undergoing routine preoperative airway assessment
• Provided written informed consent

Exclusion Criteria:

• Known congenital or acquired airway pathology
• History of difficult airway requiring advanced airway techniques
• Emergency situations requiring immediate airway management without standard preoperative assessment
• Incomplete or missing airway assessment data

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Obstetric Patients Undergoing Cesarean Section; Adult obstetric patients undergoing elective or urgent cesarean section who received standard preoperative airway assessment as part of routine anesthetic care. Airway management was performed according to institutional clinical practice without any study-related intervention.	Other: No intervention (observational study); This is an observational study. No experimental intervention was assigned. All assessments and airway management procedures were performed as part of routine clinical practice.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prediction of Difficult Airway Using Preoperative Airway Assessment Tests	The primary outcome is the ability of preoperative airway assessment tests to predict difficult airway management during cesarean delivery. Predictive performance was evaluated using sensitivity, specificity, positive and negative predictive values, and the area under the receiver operating characteristic (ROC) curve (AUC). Difficult airway was defined based on predefined intraoperative criteria such as difficulty in mask ventilation, difficult laryngoscopy, or difficult tracheal intubation as assessed by the attending anesthesiologist.	During anesthesia induction

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Difficult Airway in Obstetric Patients	The incidence of difficult airway management among obstetric patients undergoing cesarean section was evaluated based on predefined clinical criteria.	During anesthesia induction
Association Between Individual Airway Assessment Tests and Difficult Airway	The association between individual preoperative airway assessment tests and the occurrence of difficult airway management was analyzed to identify potential risk factors.	During anesthesia induction

Collaborators and Investigators

• Sponsor: Akdeniz University Hospital
• Investigators: Principal Investigator: ALİ DEMİRTAŞ, Akdeniz University Hospital

Publications and helpful links

General Publications

• Mushambi MC, Jaladi S. Airway management and training in obstetric anaesthesia. Curr Opin Anaesthesiol. 2016 Jun;29(3):261-7. doi: 10.1097/ACO.0000000000000309.
• Freedman RL, Lucas DN. MBRRACE-UK: saving lives, improving mothers' care - implications for anaesthetists. Int J Obstet Anesth. 2015 May;24(2):161-73. doi: 10.1016/j.ijoa.2015.03.004. Epub 2015 Mar 14.
• McKeen DM, George RB, O'Connell CM, Allen VM, Yazer M, Wilson M, Phu TC. Difficult and failed intubation: Incident rates and maternal, obstetrical, and anesthetic predictors. Can J Anaesth. 2011 Jun;58(6):514-24. doi: 10.1007/s12630-011-9491-9. Epub 2011 Apr 7.

Study record dates

Study Major Dates

• Study Start (Actual): August 23, 2023
• Primary Completion (Actual): August 23, 2024
• Study Completion (Actual): August 23, 2024

Study Registration Dates

• First Submitted: January 6, 2026
• First Submitted That Met QC Criteria: January 6, 2026
• First Posted (Actual): January 14, 2026

Study Record Updates

• Last Update Posted (Actual): January 14, 2026
• Last Update Submitted That Met QC Criteria: January 6, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Difficult Intubation; Mallampati Score; Preoperative Airway Assessment; Obstetric Patients
• Additional Relevant MeSH Terms: Investigative Techniques; Methods; Observation
• Other Study ID Numbers: Difficult Airway in Cesarean

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No