An observational study in Obesity (BMI>30), sponsored by Ankara City Hospital Bilkent. Not yet recruiting. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-13.
Sponsored by Ankara City Hospital Bilkent · Observational
This study aims to investigate whether body mass index (BMI) is associated with differences in the time needed to perform an ultrasound-guided infraclavicular nerve block and how well the block works. This type of regional anesthesia involves injecting a local anesthetic near the nerves below the collarbone to numb the arm for surgery.
The study will include 100 adults undergoing planned hand, wrist, or forearm surgery at Ankara Bilkent City Hospital. Researchers will compare 50 participants with a BMI below 30 kg/m² and 50 participants with a BMI of 30 kg/m² or higher.
The study will assess the time needed to perform the block, block success, the time until sensation and movement are blocked, and patient satisfaction. Researchers will also examine whether arm circumference and muscle measurements are associated with block outcomes.
This is an observational study. Participants will receive routine anesthesia and surgical care, and their treatment will not be assigned or changed for research purposes.
This single-center, prospective, observational cohort study will be conducted in the Department of Anesthesiology and Reanimation at Ankara Bilkent City Hospital. It will evaluate the association between body mass index and the performance and clinical outcomes of ultrasound-guided infraclavicular brachial plexus block in adults undergoing elective hand, wrist, or forearm surgery.
Eligible patients who provide written informed consent will be enrolled consecutively. Two cohorts will be defined according to body mass index: a non-obese cohort with BMI \<30 kg/m² and an obese cohort with BMI ≥30 kg/m², with 50 participants planned in each cohort. Cohort membership will be determined by the participants' measured BMI, without randomization or research-directed treatment allocation.
Preoperative assessments will include demographic and clinical characteristics, height, weight, BMI, arm circumference, and ultrasound-measured deltoid muscle thickness. Additional assessments will include the SARC-F questionnaire and the body composition indices specified in the study protocol.
Ultrasound-guided infraclavicular brachial plexus block will be performed as part of routine clinical care. Preparation time, block performance time, sensory block onset time, motor block onset time, and analgesia onset time will be recorded. Participants will be monitored for 30 minutes after local anesthetic injection to assess block development and readiness for surgery. Failure to achieve a sensory block sufficient for surgery within this period will be recorded as an inadequate block, and further anesthetic management will follow the clinical protocol.
Block-related comfort, needle insertion pain, ultrasound image quality, sensory and motor block adequacy, and patient and surgeon satisfaction will be assessed using the rating scales specified in the protocol. Motor function will also be assessed through wrist extension, finger flexion, and elbow flexion. Vascular puncture, paresthesia, local anesthetic systemic toxicity, hematoma, inadequate block, and other complications will be recorded.
Comparisons between BMI cohorts will use Student's t-test or the Mann-Whitney U test for continuous variables, according to their distributions, and the chi-square test for categorical variables. The relationships between anthropometric measurements and block outcomes will also be explored. No additional invasive procedures will be performed for research purposes.
6,570 studies on the registry are indexed under Obesity; 1,718 are open to participants now.
This study's planned enrollment of 100 is below the median of 132 across 1,338 observational studies indexed under Obesity.
Browse Obesity studies →Ankara City Hospital Bilkent is the lead sponsor of 437 studies on the registry; 109 are open to participants now.
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Adults aged 18 years or older with American Society of Anesthesiologists (ASA) physical status I-III who are scheduled for elective hand, wrist, or forearm surgery under ultrasound-guided infraclavicular brachial plexus block at Ankara Bilkent City Hospital, Türkiye. Eligible patients who provide written informed consent will be enrolled consecutively into two cohorts according to body mass index (BMI): BMI \<30 kg/m² and BMI ≥30 kg/m². A total of 100 participants are planned, with 50 participants in each cohort.
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Exclusion Criteria:
Adults aged 18 years or older with BMI \<30 kg/m² and ASA physical status I-III, undergoing elective hand, wrist, or forearm surgery under ultrasound-guided infraclavicular brachial plexus block as part of routine clinical care. Planned enrollment: 50 participants.
Procedure: Ultrasound-guided infraclavicular brachial plexus block
Adults aged 18 years or older with BMI ≥30 kg/m² and ASA physical status I-III, undergoing elective hand, wrist, or forearm surgery under ultrasound-guided infraclavicular brachial plexus block as part of routine clinical care. Planned enrollment: 50 participants.
Procedure: Ultrasound-guided infraclavicular brachial plexus block
Ultrasound-guided infraclavicular brachial plexus block will be performed as part of routine anesthetic care for elective hand, wrist, or forearm surgery. Local anesthetic will be injected posterior to the axillary artery under ultrasound guidance, with intermittent aspiration. Sensory and motor block development will be assessed for 30 minutes after injection. The same block technique will be used in both BMI cohorts.
Infraclavicular Block Performance Time
Time elapsed from the first insertion of the block needle through the skin to completion of the local anesthetic injection, measured in minutes. Preparation and ultrasound imaging before needle insertion are excluded. Block performance time will be compared between participants with BMI \<30 kg/m² and those with BMI ≥30 kg/m².
Time frame: During the preoperative block procedure on the day of surgery, from first block needle insertion to completion of local anesthetic injection.
Sensory Block Success at 30 Minutes
The percentage of participants achieving a sensory block sufficient to permit surgery within 30 minutes after completion of the local anesthetic injection. Failure to achieve adequate sensory blockade within this period will be classified as an inadequate block. Success rates will be compared between the BMI \<30 kg/m² and BMI ≥30 kg/m² cohorts.
Time frame: Within 30 minutes after completion of the local anesthetic injection, before surgery.
Number of Needle Skin Punctures
Total number of skin punctures made with the block needle during the infraclavicular block procedure. The initial puncture and each subsequent reinsertion after complete withdrawal of the needle from the skin will be counted. Needle redirections without complete withdrawal from the skin will not be counted as additional skin punctures.
Time frame: During the preoperative infraclavicular block procedure on the day of surgery.
Number of Needle Redirections
Total number of needle redirections during the infraclavicular block procedure. A redirection is defined as withdrawal and subsequent advancement of the needle along a different trajectory without complete removal from the skin. Initial needle advancement and reinsertion following complete withdrawal from the skin will not be counted as redirections.
Time frame: During the preoperative infraclavicular block procedure on the day of surgery.
Patient Satisfaction With Regional Anesthesia
Patient satisfaction with regional anesthesia will be assessed using a 5-point Likert scale: 1 = very dissatisfied, 2 = dissatisfied, 3 = neither satisfied nor dissatisfied, 4 = satisfied, and 5 = very satisfied. Higher scores indicate greater satisfaction.
Time frame: Once during the immediate postoperative recovery period on the day of surgery, when the participant is alert and able to respond.
Surgeon Satisfaction With Anesthetic Conditions
Surgeon satisfaction with the operating conditions provided by the regional anesthesia will be assessed using a 5-point Likert scale: 1 = very dissatisfied, 2 = dissatisfied, 3 = neither satisfied nor dissatisfied, 4 = satisfied, and 5 = very satisfied. Higher scores indicate greater satisfaction.
Time frame: Immediately after completion of surgery.
Time to Complete Motor Block
Time from completion of the local anesthetic injection to the first assessment showing complete motor blockade in all four tested nerve distributions. Elbow flexion, wrist extension, thumb opposition, and little finger abduction will assess the musculocutaneous, radial, median, and ulnar nerves, respectively. Each movement will be scored as 0 = normal strength, 1 = reduced strength with movement present, or 2 = no movement. Complete motor block is defined as a total score of 8 out of 8. Baseline motor function will be assessed before the block. Participants not reaching this endpoint within 30 minutes will be recorded as not achieving complete motor block within the observation period.
Time frame: Every 5 minutes after completion of the local anesthetic injection, up to 30 minutes.
Time to Complete Sensory Block
Time from completion of the local anesthetic injection to the first assessment showing absence of pinprick pain in all four tested nerve distributions: the lateral forearm for the musculocutaneous nerve, the palmar surface of the index finger for the median nerve, the dorsal first web space for the radial nerve, and the palmar surface of the little finger for the ulnar nerve. Sensation will be assessed before the block to establish baseline responses. Participants not reaching this endpoint within 30 minutes will be recorded as not achieving complete sensory block within the observation period.
Time frame: Every 5 minutes after completion of the local anesthetic injection, up to 30 minutes.
No study locations are listed for this record.
Plan to share: No
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