Heated Humidifiers for Noninvasive Respiratory Support and the Risk of Burns in Neonates: A Bench Evaluation

User errors in managing heated humidifiers (HHs) have been suggested to be a source of nasal burns in newborns treated with nasal CPAP. This study evaluated the risk of burns by reproducing 3 typical errors concerning the use of HHs.

Six HHs were tested on a bench in a traditional nasal CPAP setup: PMH5000, Aircon (Wilamed); MR730, MR850, MR950 (Fisher & Paykel); and H900 (Hamilton). Temperature was measured at the end of the inspiratory tubing limb. Errors tested were (1) misconnection of the HH thermal probes (NoProbe), (2) absence of gas flow while the HH is on (NoFlow), and (3) unsuitable repeated acknowledgment of the HH alarm (NoAlarm). These errors were combined in 3 standardized scenarios: (1) NoProbe + NoFlow + NoAlarm; (2) NoProbe + NoAlarm, and (3) NoFlow + NoAlarm. The NoProbe + NoFlow + NoAlarm and NoProbe + NoAlarm scenarios were not tested in the H900 and MR950 because the proprietary circuits of these HHs are equipped with embedded probes.

For each HH, the highest inspiratory gas temperature (HIGT) and the rating on a self-designed risk-of-burn scale (ie, no risk, moderate risk, or severe risk) were reported. In the NoProbe + NoFlow + NoAlarm scenario, the risk was severe for the MR730, PMH5000, MR850, and Aircon, with HIGTs of > 65°C, 58°C, 56°C, and > 65°C, respectively. In the NoProbe + NoAlarm scenario, the risk was also severe for the same 4 HHs, with HIGTs of 56°C, 47°C, 56°C, and 48°C, respectively. In the NoFlow + NoAlarm scenario, the risk was severe for the PMH5000, Aircon, and H900, with HIGTs of 52°C, > 65°C, and 49°C, respectively, and moderate for the MR730, MR850, and MR950, with HIGTs of 45°C, 47°C, and 44°C, respectively).

In case of misuse, 5 of the 6 tested devices presented a severe risk of inducing skin burns, whereas the MR950 presented a moderate risk.