Evaluation of chest seal performance in a swine model. Comparison of Asherman vs. Bolin seal

Introduction: Chest seals are externally applied devices used to treat an open pneumothorax. There is concern that chest seals used for treatment of an open pneumothorax can fail due to coagulation or malfunction of the external vent and poor skin adherence. Chest seal failure may lead to respiratory compromise or the development of a tension pneumothorax. The objective of this project was to compare the efficacy and adhesive capacity of two chest seals: Asherman and Bolin. Methods: An open pneumothorax model in the swine (30 kg) was developed to test the performance of Asherman (n = 8) and Bolin (n = 8) seals based on haemodynamic and ultrasonographic changes following intrathoracic air and blood infusion. Seal adherence measured on a scale from 0 (poor) to 3 (good) was tested on dry skin and skin soiled with blood. Results: After standardised perforation of the chest cavity and aperture blocking, an air infusion of 372 (S.D. 214 ml) was sufficient to reduce mean arterial pressure (MAP) by 20%. Both chest seals prevented a significant fall in MAP after infusion of 1500 ml air into the chest cavity, and had similar adherence scores (2.6 (S.D. 0.8) and 2.8 (S.D. 0.6)) on dry skin. However, on blood soiled skin the Bolin seal had a higher score (2.7 (S.D. 0.6) vs. 0.4 (S.D. 0.7); p < 0.01). Ultrasound did not yield interpretable results to differentiate between Asherman and Bolin seals. Conclusions: The Bolin and Asherman chest seals were equivalent in preventing the development of a tension pneumothorax in this open pneumothorax model. However, the Bolin chest seal demonstrated stronger adherence in blood soiled conditions.