title: An in vitro study to evaluate the utility of the "air test" to infer perineural catheter tip location.
abstract: Injection of air under ultrasound guidance via a perineural catheter after insertion ("air test") has been described as a means to infer placement accuracy, yet this test has never been rigorously evaluated. We tested the hypothesis that the air test predicts accurate catheter location greater than chance and determined the test's sensitivity, specificity, and positive and negative predictive values using a porcine-bovine model and blinded expert in ultrasound-guided regional anesthesia. The air test improved the expert clinician's assessment of catheter tip position compared to chance, but there was no difference when compared to direct visualization of the catheter without air injection.
authors: Department of Anesthesia, VA Palo Alto Health Care System, Palo Alto, CA 94304 USA.
authors: Jack M
authors: JM
authors: Kan
authors: T Kyle
authors: TK
authors: Harrison
authors: T Edward
authors: TE
authors: Kim
authors: Steven K
authors: SK
authors: Howard
authors: Alex
authors: A
authors: Kou
authors: Edward R
authors: ER
authors: Mariano
mesh_terms: D000388:Air / Q000032:analysis*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D002406:Catheterization, Peripheral / Q000379:methods*; D002417:Cattle; D066298:In Vitro Techniques; D007263:Infusions, Parenteral / Q000379:methods; D009407:Nerve Block / Q000379:methods*; D010525:Peripheral Nerves / Q000000981:diagnostic imaging* / Q000187:drug effects; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D018084:Ultrasonography, Interventional / Q000379:methods*
chemical_list: D000779:Anesthetics, Local