Evaluation of the Safety and Efficiency of a New Suction Catheter Design

Abstract

We compared the safety in vivo and the secretion-removal efficiency in vitro of four suction catheters, all size 14F: the Aero-Flo, Regu-Vac, and Tri-Flo—all available commercially—and the Aspir-Safe, a prototype with an atraumatic tip configuration based on principles of the Aero-Flo design but with elimination of the Aero-Flo's flared ring, which can impede nasal insertion. Method: Our in-vivo study was conducted in 10 conscious adult female sheep. The catheter to be tested was attached to a fiberoptic bronchoscope, and each test was recorded by a color video camera attached to the eyepiece of the bronchoscope. Taking care to avoid touching the airways with the bronchoscope tip, we performed an 8-minute cycle of catheter advancement, rotation, and retraction, with and without suction of 120 torr, to simulate a worst-case clinical situation. The videotape of the test was then analyzed and scored by two observers who were not aware which catheter had been used. In our in-vitro study of secretion-removal efficiency—for which we used a glass trachea model, synthetic mucus with viscosities of 30, 60, and 90 poise, and vacuum levels of 40, 80, and 120 torr—we weighed the amounts of synthetic mucus suctioned by the test catheter while a mechanical arm relocated the catheter continuously to simulate all possible in-vivo positions. To analyze the airway trauma scores, we used the Kruskal-Wallis one-way analysis of variance and a post-hoc test for determination of pair-wise differences; to analyze the suctioning efficiency results, we used the three-way analysis of variance and post-hoc comparisons by Newman-Keuls test. Results: In vivo: The scoring of airway damage by the two observers did not differ significantly. Trauma scores of the prototype Aspir-Safe and the Aero-Flo did not differ significantly, and both were judged by the observers to be significantly less traumatic than the Regu-Vac and Tri-Flo (P < 0.05). In vitro: The Aspir-Safe and Tri-Flo had similar secretion-removal efficiency, and in most instances both were significantly more efficient than the Regu-Vac or the Aero-Flo (P < 0.05). Conclusion: We concluded that when both safety and efficiency are considered, the new Aspir-Safe is superior to the other three suction catheters.