A Better Standard to Assess the Performance of Portable Suction Devices: Time-Averaged Air Flow Rate

Portable suction devices are important tools in airway management, yet evaluating their performance and adherence to standards presents challenges. This study explores the inadequacies of ISO 10079-1 and proposes a shift from instantaneous maximum air flow rate metric to time-averaged air flow rate metric for more accurate assessment. The focus is on the importance of effective suction in prehospital care, especially in scenarios like combat and civilian emergencies.

Four portable suction devices (AMBU RES-QUE, LAERDAL VVAC, LAERDAL LCSU4, and SSCOR QUICKDRAW) were tested for air flow rate, liquid flow rate, and vacuum pressure. The study introduced the concept of time-averaged air flow rate as a more relevant metric than instantaneous maximum air flow rate. Statistical analyses, including Pearson correlation and regression methods, were employed to evaluate the relationship between instantaneous maximum and time-averaged air flow rates and their impact on liquid flow rate.

The AMBU RES-QUE showed 15.7 ± 0.4 L/min instantaneous and 2.3 ± 0.1 L/min time-averaged air flow rate; VVAC had 29.1 ± 5.4 L/min instantaneous and 6.0 ± 1.1 L/min time averaged; LCSU4, 21.8 ± 0.2 L/min instantaneous and 19.8 ± 0.4 L/min time averaged; and SSCOR QUICKDRAW, 11.3 ± 0.1 L/min instantaneous and 10.3 ± 0.1 L/min time-averaged. Water liquid flow rates (L/min) were 2.1 ± 0.1 (AMBU), 2.9 ± 0.2 (VVAC), 7.0 ± 0.1 (LCSU4), and 5.4 ± 0.0 (SSCOR); with ISO vomit simulant, they were 2.0 ± 0.3, 2.1 ± 0.4, 3.1 ± 0.4, and 2.2 ± 0.0, respectively. Time-averaged air flow rate correlated strongly with liquid flow rate (r = 0.97, R² = 0.93), whereas instantaneous maximum air flow rate correlated poorly (r =  - 0.15, R² = 0.02).

The findings challenge the common reliance on instantaneous maximum air flow rate as a performance indicator. Instantaneous maximum air flow rate may mislead users about a device's effectiveness, especially in long-term applications. Time-averaged air flow rate shows improved prediction of liquid flow rate. The study also identifies backflow issues in a manual suction device, emphasizing potential risks and the need for further exploration.

The study advocates for a shift in standards, proposing the inclusion of time-averaged air flow rate in ISO requirements. This change aligns with the patient-centric focus, providing a more accurate representation of a device's performance in real-world scenarios. Additionally, the identification of backflow in manual devices raises concerns, urging further investigation into its clinical significance and potential risks.