In this randomized, double-blind study, we compared the anesthetic characteristics and pulmonary function changes of 0.33% bupivacaine and 0.33% ropivacaine used for interscalene brachial plexus (IBP) anesthesia in patients with chronic renal failure. Forty-two patients undergoing IBP anesthesia for creation of arteriovenous fistulas were randomly allocated to receive either 30 mL of 0.33% bupivacaine (Group B) or 0.33% ropivacaine (Group R). Block onset time, diaphragmatic excursion (ultrasonographic evaluation), and free plasma concentrations of bupivacaine and ropivacaine were evaluated. Negative motion or immobility of the ipsilateral hemidiaphragm and a decrease of >10 mm in positive motion were defined as diaphragmatic paresis. The pulmonary function variables were measured by bedside spirometry equipment. Seven patients needed supplemental local anesthetic, one with total spinal block; these patients were excluded from the study. The success rate was 80.9%. Block quality was similar in the two groups. Ipsilateral hemidiaphragmatic excursion was decreased in both groups compared with baseline values (P < 0.05). Diaphragmatic paresis was identified in 10 of 16 patients and 8 of 18 patients in Groups B and R, respectively (P > 0.05). Pulmonary function significantly decreased from baseline in both groups (forced vital capacity (FVC) 30%, forced expiratory volume at 1 second (FEV1) 32%, and peak expiratory flow (PEF) 31% in Group B and FVC 17%, FEV1 17%, and PEF 5% in Group R) (P < 0.001). The decreases in Group B were larger than those in Group R (P < 0.05). Three patients in Group B and one in Group R had mild respiratory problems (P > 0.05). Concentrations of bupivacaine and ropivacaine were below toxic levels rather than “normal range.” We conclude that pulmonary function decreased more after IBP with 0.33% bupivacaine than with 0.33% ropivacaine.
IMPLICATIONS: This study was performed to compare the anesthetic characteristics and pulmonary function changes of 0.33% bupivacaine and 0.33% ropivacaine for interscalene brachial plexus block in patients with chronic renal failure. The overall success rate was 80.9%. Block quality was similar in both groups. The decreases in pulmonary function variables were less in patients given ropivacaine 0.33%.
Departments of *Anesthesiology, †Radiology, ‡Thoracic Surgery, and §Pediatrics, Metabolism Division Laboratory, Istanbul University Cerrahpasa Medical School, Istanbul, Turkey
Presented at the 22nd Annual European Society of Regional Anaesthesia Congress 2003, Malta, and published as a scientific abstract in Regional Anesthesia and Pain Medicine [2003;28(Suppl 1):43].
Accepted for publication September 3, 2004.
Address correspondence and reprint requests to Fatis Altintas, MD, Nispetiye Cad Prof Sitesi A-2 Blok D 9, Etiler, Istanbul, Turkey. Address e-mail to firstname.lastname@example.org.