Comparison of Different Approaches for Supraclavicular Block and Their Effects on Diaphragm Muscle Function

In this prospective randomized double-blind study, patients will be divided into 3 groups using a computer program.

Standard monitoring (ECG, pulse oximetry, noninvasive blood pressure) will be applied to the patients who will then be taken to the block application room . After the peripheral vascular access is established on the hand that will not be operated on, premedication will be provided with 2 mg iv midazolam.

The blocks will be performed by an experienced anesthesiologist with the USG guidance. Block evaluation and measurements will be made by a different experienced anesthesiologist. After the antisepsis of the area to be blocked, a 22G 50 mm stimulator needle will be used for the block. Intermittent negative aspiration will be performed during all procedures to detect possible vascular puncture. The local anesthetic mixture we routinely use in our clinic will be used. 20 ml of bupivacaine(Buvicaine HCl %0.5) and prilocaine(Priloc HCl %2) 1:1 mixture will be prepared in a way that there will be 5mcg adrenaline per ml.(9ml bupivacaine, 9ml prilocaine and 2ml saline with 50 mcg adrenaline per ml) The ultrasound probe will be placed on the clavicle, the supraclavicular block will be applied in the coronal oblique plane using the in-plane technique.

3 different approaches of supraclavicular block will be compared. Approaches share the same probe position and needle entry point but differ in where the local anesthetic is given.

Group 1: Local anesthetic mixture will be given to the corner pocket - where the artery and the first rib intersect in the sonoanatomical image.

Group 2: 10 ml of the local anesthetic mixture will be given to the described corner pack and the remaining 10 ml into the largest nerve cluster (Intracluster injection).

Group 3: Local anesthetic mixture will be administered by multi injection method between the nerve groups seen in the sonoanatomical image.

The diaphragm thickening fraction and evaluations will be made by another experienced anesthesiologist, double-blindness will be achieved by being blind to the patient's group.

Effects of phrenic nerve block on diaphraghma muscle will be evaluated by diaphraghma thickining fraction.All patients will be evaluated with USG in a head-up position facing the side to be operated before and 30 minutes after the block is performed.The probe will be placed perpendicular to the chest wall, in the eighth or ninth intercostal space, between the anterior axillary and midaxillary lines, 0.5 to 2 cm below the costophrenic sinus.

The diaphragm will be viewed as a structure with three distinct layers, including two parallel echoic lines (Diaphragmatic pleura and peritoneum) and a hypoechoic line between them (Diaphragm muscle) . The patient will be instructed to breathe up to total lung capacity (TLC) and then exhale to residual volume (RV).

Several diaphragm images will be taken, at least three at the point of maximum thickening in TLC and at least three at minimum thickness in RV.

On each B-mode image, diaphragm thickness will be measured from the middle of the pleural line to the middle of the peritoneal line. Then DTI will be calculated as a percentage from the following formula:

(Max thickness at the end of inspiration - Max thickness at the end of the expiration) / Max thickness at the end of the expiration.

With this formula, we can determine the involvement of phrenic nerve by looking at the rate of diaphragm thickening before and after supraclavicular block in different groups.

As a first line rescue anesthesia, patients will receive sedoanalgesia with remifentanil infusion. Laryngeal mask and general anesthesia will be commenced if needed. The postoperative analgesic regimen will routinely contain 1000 mg IV acetaminophen (3x1) and, if necessary, 1 mg opioid (Tramadol) per kg will be given.

Inclusion criteria

• Patients who are scheduled scheduled for hand, wrist, forearm, arm surgery
• Patients who has informed consent for study
• Patients with American Society of Anesthesiologists Physical Status Classification(ASA) I,II and III

Exclusion criteria

• Patient's refusal to participate
• Patients under 18 years of age
• Patients with known local anesthetic allergy
• Patients with Body mass index> 35
• Patients diagnosed sepsis and bacteriemia,
• Skin infection at the injection site,
• History of coagulopathy or anticoagulant therapy
• Patients with uncontrolled diabetes,
• Uncoordinated patients,
• Psychological and emotional lability,
• Patients with anatomical disorders at application points
• Pregnant patients