Background: Interscalene brachial plexus block (ISB) provides excellent analgesia for arthroscopic shoulder surgeries but is associated with adverse effects including hemidiaphragmatic paresis. We aimed to compare the respiratory effects, forced vital capacity (FVC), and forced expiratory volume in 1 second (FEV1) between suprascapular nerve block (SSB) and ISB. Methods: Sixty patients were recruited and randomized into ISB, anterior SSB, and posterior SSB groups. FVC, FEV1, and diaphragmatic excursion were evaluated at baseline and 30 minutes after intervention. Blocks were performed under ultrasound guidance with 15 ml of 0.5% ropivacaine. Pain scores were assessed at 6, 12, and 24 hours postoperatively. Results: The ISB group showed a reduced FVC of 31.2% ± 17.5% (mean ± SD), while the anterior and posterior SSB groups had less reduction of 3.6% ± 18.6% and 6.8% ± 6.5%, respectively (P < 0.001). The ISB group showed more reduction in diaphragmatic excursion than the anterior and posterior SSB groups (median [IQR]): −85.7% (−95.3% to −63.3%) vs. −1.8% (−13.1% to 2.3%) and −1.2% (−8.8% to 16.8%), respectively (P < 0.001). The median pain scores (IQR) in the ISB and anterior SSB groups were lower than those in the posterior SSB group at 6 hours on movement: 0 (0–2), 1.8 (0–4.5) vs. 5 (2.5–8), respectively (P = 0.002). There was no significant difference in oxycodone consumption postoperatively. Conclusions Anterior SSB preserves lung function and has a comparable analgesic effect as ISB. Thus, it is recommended for arthroscopic shoulder surgeries, especially in patients who have reduced lung function.

INTRODUCTIONComplications occur in over 15% of central venous cannulations, often a result of anatomical variations. This study aimed to determine the anatomical variations of the internal jugular vein (IJV), demonstrate the likely success of cannulation and assess the risk of carotid artery (CA) injury when catheterising the IJV using the external landmarks technique at various degrees of head rotation in the local population.

METHODS100 elective cardiac surgical patients were prospectively enrolled. Simulated catheterisations were performed with patients placed in the Trendelenburg position. The standard landmark technique was used to identify anatomy. Simulations were done at six different degrees of rotation of the head: 0°, 30° and 60° for both right and left IJVs. Difficult catheterisation was defined as an IJV diameter < 7 mm.

RESULTSThere was no thrombosed or absent IJV in any patient. Catheterisation was potentially difficult in 15% of patients at 30° head rotation and more difficult for the left IJV than the right (20% vs. 10%; p < 0.05). The simulated needle hit the IJV in 82% of the attempts, but the needle was in the middle 80% of the vein only 70% of the time. Neck rotation increased the degree of overlap of the CA relative to the IJV from 20%-30% to 50%.

CONCLUSIONAnatomical variations play a significant role in determining the success of IJV catheterisation as well as the incidence of catheterisation-associated complications. This study emphasises the importance of using ultrasonography to guide IJV catheterisation, even in patients with seemingly normal neck anatomy.

Adult ; Aged ; Aged, 80 and over ; Carotid Artery Injuries ; epidemiology ; etiology ; prevention & control ; Catheterization, Central Venous ; adverse effects ; methods ; Female ; Follow-Up Studies ; Humans ; Jugular Veins ; anatomy & histology ; Male ; Middle Aged ; Posture ; Prospective Studies ; Risk Factors ; Young Adult