Effect of Liposomal Bupivacaine and Bupivacaine Hydrochloride for Superior Trunk Block of the Interscalene Brachial Plexus on Postoperative Diaphragmatic Function and Analgesia

Observe diaphragmatic movement through the hepatic or splenic acoustic window and measure the amplitude of diaphragmatic excursion on the anesthetized side using M-mode (average of 3 waveforms). Diaphragmatic Function Evaluation[4,5]: A decrease in diaphragmatic excursion amplitude during deep breathing of <25% compared to pre-block is defined as normal diaphragmatic movement. A decrease of 25%-75% is defined as partial diaphragmatic paralysis. A decrease of >75% is defined as complete diaphragmatic paralysis.

Observe diaphragmatic movement through the hepatic or splenic acoustic window and measure the amplitude of diaphragmatic excursion on the anesthetized side using M-mode (average of 3 waveforms). Diaphragmatic Function Evaluation[4,5]: A decrease in diaphragmatic excursion amplitude during deep breathing of <25% compared to pre-block is defined as normal diaphragmatic movement. A decrease of 25%-75% is defined as partial diaphragmatic paralysis. A decrease of >75% is defined as complete diaphragmatic paralysis.

Pain intensity at the surgical site will be assessed using the 11-point Numeric Rating Scale (NRS), where 0 represents "no pain" and 10 represents "the worst pain imaginable." Patients will self-report their pain intensity at rest (Resting NRS) and during active movement (Dynamic NRS)

The Pain Intensity-Area Under the Curve (PI-AUC) will be calculated as a summary measure of overall pain burden over time. The AUC for each patient will be computed for three consecutive postoperative periods based on the serial NRS scores (both resting and dynamic) collected during those intervals. A smaller AUC indicates better overall analgesic control during the specified period.

Patient-reported recovery quality will be assessed using the 15-item Quality of Recovery (QoR-15) questionnaire. This validated tool evaluates physical comfort, physical independence, psychological support, emotional state, and pain. Scores range from 0 (extremely poor recovery) to 150 (excellent recovery). The upward trend of the QoR-15 score signifies a progressive and comprehensive improvement in a patient's postoperative recovery experience across physical, emotional, and functional domains.

Patient satisfaction with analgesia and its associated side effects will be evaluated using the Overall Benefit of Analgesia Score (OBAS). The OBAS is a composite score (range 0-28, lower is better) incorporating assessments of pain intensity, nausea/vomiting, dizziness, sedation, itching, and patient satisfaction. The downward trend of the OBAS score indicates a progressively more favorable balance between analgesic efficacy and the burden of treatment-related side effects, representing an increasing net benefit of the analgesia regimen.

The total consumption of all opioid analgesics administered to the patient (including patient-controlled analgesia and rescue doses). All opioid doses will be converted to intravenous morphine milligram equivalents (MME) using standard conversion ratios for summation and comparison. A lower morphine equivalent consumption indicates better analgesic efficacy and a longer duration of action for liposomal bupivacaine.

This refers specifically to the summed dose of supplemental (rescue) opioid analgesics administered upon patient request for breakthrough pain. The cumulative dose for each period will be calculated and expressed in intravenous morphine milligram equivalents (MME). A lower morphine equivalent consumption indicates better analgesic efficacy and a longer duration of action for liposomal bupivacaine.

Vascular injury: Evidence of hematoma or vascular puncture during needle placement.

Hoarseness: Patient-reported or clinician-identified voice change suggestive of recurrent laryngeal nerve involvement.

Horner's syndrome: Presence of ptosis, miosis, and/or anhidrosis on the blocked side.

Diaphragmatic paralysis: defined by a reduction in diaphragmatic excursion amplitude >25% from baseline on ultrasound assessment performed post-block.

SpO2 <90% on room air after PACU discharge: Oxygen saturation falling below 90% while breathing room air, occurring after the patient has been discharged from the PACU, and not related to other obvious causes.

Dyspnea: Subjective sensation of shortness of breath or labored breathing. Finger numbness: Persistent numbness or loss of sensation in the fingers of the blocked upper limb.

Motor difficulty: Persistent weakness or inability to perform specific voluntary movements in the blocked upper limb.

Patients will be contacted by telephone at 3 months after surgery. They will be asked to self-report their current average pain intensity over the past 24 hours at the surgical site using the 11-point Numeric Rating Scale (NRS, 0-10), where 0 represents "no pain" and 10 represents "the worst pain imaginable." This assesses the potential long-term impact of the analgesic intervention on persistent postoperative pain.