An observational study in Residual Neuromuscular Blockade, Diaphragm Dysfunction and Postoperative Pulmonary Complications, sponsored by Mustafa Duran. Not yet recruiting. Open to participants aged 18 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-11-03.
Sponsored by Mustafa Duran · Observational
The goal of this prospective observational study is to learn whether diaphragm ultrasound and quantitative neuromuscular monitoring can predict early respiratory events after extubation in adults having elective surgery under general anesthesia.
The main questions it aims to answer are:
Participants will receive their usual anesthesia care. Diaphragm ultrasound will be performed at four time points: before induction of anesthesia, 5 minutes after induction, before extubation, and 30 minutes after extubation in the post-anesthesia care unit (PACU). The TOF ratio will be recorded with routine quantitative neuromuscular monitoring. Respiratory events will be recorded from extubation until discharge from the PACU.
Safe extubation after general anesthesia depends on adequate recovery of respiratory muscle function. In routine practice, extubation decisions are based on clinical criteria and, when available, a TOF ratio of 0.9 or higher. However, a normal TOF ratio measured at the adductor pollicis does not always reflect full functional recovery of the diaphragm. Diaphragm ultrasonography is a non-invasive bedside method that allows direct assessment of diaphragm thickness, diaphragm thickening fraction (DTF) and diaphragm excursion. Most studies evaluating diaphragm ultrasound for extubation have been performed in intensive care unit patients; data in patients extubated in the operating room after elective surgery are limited.
This single-center, prospective observational cohort study will be conducted at Marmara University Pendik Training and Research Hospital, Department of Anesthesiology and Reanimation. Adult patients (18-75 years, ASA I-III) undergoing elective surgery in the supine position under general anesthesia with neuromuscular blockade will be included after written informed consent.
Ultrasound protocol: The right hemidiaphragm will be assessed in the supine position. Diaphragm thickness at end-inspiration (Tinsp) and end-expiration (Texp) will be measured with a linear probe at the zone of apposition, and DTF will be calculated as (Tinsp - Texp) / Texp x 100. Diaphragm excursion will be measured with M-mode ultrasound. Measurements will be obtained at four time points: before induction (T0), 5 minutes after induction under controlled ventilation (T1), before extubation during spontaneous breathing with the patient cooperative (T2), and 30 minutes after extubation in the PACU (T3). Each parameter will be measured three times and the mean value will be used.
Neuromuscular monitoring: The neuromuscular blocking agent, total dose (mg and mg/kg), time from last dose to extubation, reversal agent and dose, and the TOF ratio at extubation will be recorded.
The extubation decision will be made by the attending anesthesiologist according to routine clinical assessment, independent of the study measurements. Patients will be observed in the PACU for at least 30 minutes after extubation.
Statistical analysis: Patients with and without early respiratory events will be compared using the t-test or Mann-Whitney U test for continuous variables and the chi-square or Fisher exact test for categorical variables. Changes in diaphragm parameters across time points will be analyzed with repeated-measures ANOVA or the Friedman test. Correlation between diaphragm parameters and the TOF ratio will be assessed with Pearson or Spearman correlation. Independent predictors of early respiratory events will be identified with logistic regression, and the predictive performance of diaphragm parameters will be evaluated with ROC analysis (AUC, sensitivity, specificity, optimal cut-off). A sample size of 90 patients was calculated (two-tailed, effect size d = 0.60, alpha = 0.05, power = 0.80); 100 patients will be enrolled to account for possible data loss.
98 studies on the registry are indexed under Delayed Emergence from Anesthesia; 17 are open to participants now.
This study's planned enrollment of 100 is close to the median of 100 across 39 observational studies indexed under Delayed Emergence from Anesthesia.
Browse Delayed Emergence from Anesthesia studies →This is the only study on the registry with Mustafa Duran as lead sponsor.
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Consecutive adult patients (18-75 years, ASA I-III) scheduled for elective surgery in the supine position under general anesthesia with neuromuscular blockade at Marmara University Pendik Training and Research Hospital, Istanbul, Türkiye.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adult patients (18-75 years, ASA I-III) undergoing elective surgery in the supine position under general anesthesia with neuromuscular blockade and planned extubation at the end of surgery.
Diagnostic Test: Diaphragm ultrasonography4
Right hemidiaphragm ultrasonography in the supine position. Diaphragm thickness at end-inspiration and end-expiration is measured with a linear probe at the zone of apposition, and diaphragm thickening fraction is calculated. Diaphragm excursion is measured with M-mode. Each parameter is measured three times at four time points: before induction, 5 minutes after induction, before extubation, and 30 minutes after extubation in the PACU.
Incidence of early postoperative respiratory events
Composite of any of the following: SpO₂ \< 92% lasting at least 30 seconds; airway obstruction requiring jaw thrust; need for mask ventilation; laryngospasm; apnea (at least 15 seconds) or hypoventilation (respiratory rate \< 8/min for at least 1 minute); need for non-invasive ventilation; reintubation.
Time frame: From tracheal extubation until discharge from the post-anesthesia care unit (PACU), assessed up to 2 hours
Predictive accuracy of diaphragm thickening fraction
Area under the ROC curve, sensitivity, specificity and optimal cut-off of DTF measured before extubation for predicting early respiratory events.
Time frame: Diaphragm measured immediately before tracheal extubation (T2); respiratory events assessed from extubation until PACU discharge, up to 2 hours
Predictive accuracy of diaphragm excursion
Area under the ROC curve, sensitivity, specificity and optimal cut-off of diaphragm excursion (cm) measured before extubation for predicting early respiratory events.
Time frame: Diaphragm measured immediately before tracheal extubation (T2); respiratory events assessed from extubation until PACU discharge, up to 2 hours
Change in diaphragm thickening fraction from baseline
Percentage change in DTF before extubation compared with the pre-induction value.
Time frame: Before induction (T0) and before extubation (T2)
Diaphragm parameters across time points
Diaphragm thickness, DTF (%) and excursion (cm) at four time points.
Time frame: Before induction (T0), 5 minutes after induction (T1), before extubation (T2), 30 minutes after extubation (T3)
Correlation between TOF ratio and diaphragm parameters
Correlation coefficient between the TOF ratio at extubation and DTF and diaphragm excursion before extubation.
Time frame: Immediately before tracheal extubation
Incidence of individual respiratory events
Incidence of each component of the primary composite outcome.
Time frame: From tracheal extubation until discharge from the post-anesthesia care unit (PACU), assessed up to 2 hours
No study locations are listed for this record.
Plan to share: No — Individual participant data will not be shared publicly; de-identified data may be made available by the principal investigator upon reasonable request.
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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